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Recent IIHR Journal Publications

IIHR researchers and students produce hundreds of peer-reviewed journal articles every year.

IIHR researchers and students produce hundreds of peer-reviewed journal articles every year.

IIHR researchers publish hundreds of articles in professional journals each year, as well as a number of books through commercial publishers. This page highlights some of their most recent publications.

 

  • Jadidoleslam, N., R. Mantilla,W.F. Krajewski and M. Cosh, Data-driven stochastic model for basin and sub-grid variability of SMAP satellite soil moisture, Journal of Hydrology, 2019 (in press). Summary: A stochastic model was created to create high resolution surface soil moisture information.
  • Keem, M., B.-C. Seo, W.F. Krajewski, and K.R. Morris, Inter-comparison of reflectivity measurements between GPM DPR and NEXRAD Radars, Atmospheric Research, 2019 (in press). Summary: Reflectivity measurements are one example of a measurement that can be taken from GPM, DPR, and NEXRAD radars. This study demonstrates the potential use of the NASA’s Global Precipitation Measurement (GPM) Dual-frequency Precipitation Radar (DPR) to examine ground radar (GR) miscalibration and other uncertainty sources (e.g., partial beam blockage).
  • Seo, B.-C., M. Keem, R. Hammond, I. Demir, and W.F. Krajewski, A pilot infrastructure for searching rainfall metadata and generating rainfall product using the Big Data of NEXRAD, Environmental Modeling and Software, 117, 69–75, 2019. Summary: NEXRAD collects and stores rainfall data in a cloud, allowing the IFC to develop a program to retrieve the data and create a map. The map has the benefit of allowing researchers to choose a specific area of study.
  • Barth, N.A., G. Villarini, and K. White, Accounting for mixed populations in flood frequency analysis: A Bulletin 17C perspective, Journal of Hydrologic Engineering, 24(3), 1-12, 2019. Summary: This study provides a general statistical framework to perform a process-driven flood frequency analysis using a weighted mixed population approach. Furthermore, it allows for accounting for both sampling and mixing uncertainties.
  • Chen, B., W.F. Krajewski, M. Helmers, and Z. Zhang, Spatial variability and temporal persistence of event runoff coefficients over agricultural land, Water Resources Research, 55(2), 1583-1597, 2019. Summary: The analysis of unique rainfall-runoff data can offer more in-depth knowledge than the current internal spatial variability of small-scale runoff yield. Through the use of 12 unique hills, the authors intend to reduce the error of runoff data.
  • Ayers, J.R., G. Villarini, C.S. Jones, and K.E. Schilling, Changes in monthly baseflow across the U.S. Midwest, Hydrological Processes, 33(5), 748-758, 2019. Summary: Characterizing streamflow changes in the agricultural U.S. Midwest is critical for effective planning and management of water resources throughout the region. The objective of this study is to determine if and how baseflow has responded to land alteration and climate changes across the study area during the 50‐year study period by exploring hydrologic variations based on long‐term stream gage data.
  • Slater, L.J., G. Villarini, and A.A. Bradley, Evaluation of the skill of North-American Multi-Model Ensemble (NMME) global climate models in predicting average and extreme precipitation and temperature over the continental USA, doi:10.1007/s00382-016-3286-1, Climate Dynamics, 2019 (in press). Summary: This paper examines the forecasting skill of eight Global Climate Models from the North-American Multi-Model Ensemble project (CCSM3, CCSM4, CanCM3, CanCM4, GFDL2.1, FLORb01, GEOS5, and CFSv2) over seven major regions of the continental United States.
  • Slater, L.J., G. Villarini, A.A. Bradley, and G.A. Vecchi, A dynamical statistical framework for seasonal streamflow forecasting in an agricultural watershed, Climate Dynamics, 2019 (in press). Summary: The state of Iowa in the US Midwest is regularly affected by major floods and has seen a notable increase in agricultural land cover over the twentieth century. We present a novel statistical-dynamical approach for probabilistic seasonal streamflow forecasting using land cover and General Circulation Model (GCM) precipitation forecasts.
  • Neri, A., G. Villarini, K. Salvi, L.J. Slater, and F. Napolitano, On the decadal predictability of the frequency of flood events across the U.S. Midwest, s International Journal of Climatology, 2019 (in press). Summary: Skilful predictions of the frequency of flood events over long lead times (e.g., from 1 to 10 years ahead) are essential for governments and institutions making near‐term flood risk plans. However, little is known about current flood prediction capabilities over annual to decadal timescales. Here we address this knowledge gap at 286 U.S. Geological Survey gaging stations across the U.S. Midwest using precipitation and temperature decadal predictions from the Coupled Model Intercomparison Project (CMIP) phase 5 models.
  • ElSadaani, M., W.F. Krajewski, and D.L. Zimmerman, River network based characterization of errors in remotely sensed rainfall products in hydrological applications, Remote Sensing Letters, 9(8), 743–752, 2018. Summary: The authors propose a hydrologic evaluation framework for gridded rainfall products. The framework will aid in the compilation of rainfall data and lower the chance for errors with satellite rainfall products in hydrologic applications.
  • ElSadaani, M., W.F. Krajewski, R. Goska, and M. Smith, An investigation of errors in distributed models’ stream discharge prediction due to channel routing, Journal of the American Water Resources Association, 54(1), 1-10, 2018. Summary: The authors analyzed the results of the Land Surface Model and the Routing Application for Parallel Computation of Discharge. The authors took the results – which showed that enhancements were still possible for the programs – and investigated the source of the errors. Their research resulted in an improvement in model performance.
  • Villarini, G., and L.J. Slater, Examination of changes in annual maximum gauge height in the continental United States using quantile regression, Journal of Hydrologic Engineering, 23(3), 1-5, 2018. Summary: This study focuses on the detection of temporal changes in annual maximum gauge height (GH) across the continental United States and their relationship to changes in short- and long-term precipitation. Analyses are based on 1,805 U.S. Geological Survey records over the 1985–2015 period and are performed using quantile regression. Trends were significant only at a limited number of sites, with a higher number of detections at the tails of the distribution.
  • Nayak, M.A, and G. Villarini, Remote sensing-based characterization of rainfall during atmospheric rivers over the central United States, Journal of Hydrology, 556, 1038-1049, 2018. Summary: This study fills this major scientific gap by describing the rainfall during ARs over the central United States using five remote sensing-based precipitation products over a 12-year study period. The products we consider are: Stage IV, Tropical Rainfall Measuring Mission – Multi-satellite Precipitation Analysis (TMPA, both real-time and research version); Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks (PERSIANN); the CPC MORPHing Technique (CMORPH).
  • Dhanya, C.T., and G. Villarini, On the inherent predictability of precipitation across the United States, Theoretical and Applied Climatology, 133, 1035-1050, 2018. Summary: This study investigates the spatial distribution of predictability of daily precipitation across the USA. The emphasis is on determining the rate of increase in predictability with spatio-temporal averaging, by defining three predictability statistics (maximum predictability, predictive error, and predictive instability) based on the nonlinear finite-time Lyapunov exponent.
  • Slater, L.J., and G. Villarini, Enhancing the predictability of seasonal streamflow via a statistical-dynamical approach, Geophysical Research Letters, 45, 6504-6513, 2018. Summary: Here we conduct systematic forecasting of seasonal streamflow using eight GCMs from the North American Multi‐Model Ensemble, 0.5–9.5 months ahead, at 290 stream gauges in the U.S. Midwest. This paper paves the way for novel forecasting approaches using dynamical GCM predictions within statistical frameworks.
  • Giuntoli, I., G. Villarini, C. Prudhomme, and D.M. Hannah, Uncertainties in projected runoff over the conterminous United States, Climatic Change, 150(3), 149-162, 2018. Summary: Using a set of GIMs driven by GCMs under different representative concentration pathways (RCPs), this study aims to partition the uncertainty of future flows coming from GIMs, GCMs, RCPs, and internal variability over the CONterminous United States (CONUS).
  • Zhang, W., G. Villarini, G.A. Vecchi, and J.A. Smith, Urbanization exacerbated the rainfall and flooding caused by hurricane Harvey in Houston, Nature, 563, 384-388, 2018. Summary: Using the Weather Research and Forecast model—a numerical model for simulating weather and climate at regional scales—and statistical models, we quantify the contribution of urbanization to rainfall and flooding. Overall, we find that the probability of such extreme flood events across the studied basins increased on average by about 21 times in the period 25–30 August 2017 because of urbanization.
  • Demir, I., Yildirim, E., Sermet, Y., Sit, M., FLOODSS: Iowa Flood Information System as a Generalized Flood Cyberinfrastructure, International Journal of River Basin Management, 16:3, 393-400, 2018. Summary: This article presents the vision, implementation, and case studies of the Iowa Flood Information System (IFIS) towards the vision for next-generation decision support systems for flooding. The IFIS is an end-to-end web-based platform that incorporates various aspects of the decision-making process for flood risk management and mitigation for the State of Iowa. The IFIS provides real-time information on streams and weather conditions, incorporates advanced hydrological models for flood prediction and mapping, and several data analytics and visualization tools to support effective decision-making process.
  • Carson, A., Windsor, M., Hill, H., Haigh, T., Wall, N., Smith, J., Olsen, R., Bathke, D.,Demir, I., Muste, M., Serious Gaming Based Participatory Planning for Mitigation of Flood, Drought, and Water Quality, International Journal of River Basin Management, 16:3, 379-391, 2018. Summary: Collaborative, holistic, and proactive planning for basin-wide water management solutions addressing multiple water-related hazards is challenging. Shared vision planning (SVP) and decision support systems (DSSs) are two approaches that have been used to address the challenges described. SVP is a participatory planning process. DSSs can efficiently support the integration of multiple and vast amounts of information and interactively illustrate the trade-offs between alternative mitigation plans.
  • Sermet, Y., Demir, I., An Intelligent System on Knowledge Generation and Communication for Flooding, Environmental Modeling and Software, 108, 51-60, 2018. Summary: Communities are at risk from extreme events and natural disasters that can lead to dangerous situations for residents. Improving resilience by helping people learn how to better prepare for, recover from, and adapt to disasters is critical to reduce the impacts of these extreme events. This project presents an intelligent system, Flood AI, designed to improve societal preparedness for flooding by providing a knowledge engine that uses voice recognition, artificial intelligence, and natural language processing based on a generalized ontology for disasters with a primary focus on flooding.
  • Quintero, F., W.F. Krajewski, Conflating the Iowa Flood Center high-resolution river network with the National Water Center NHDPlus network, Journal of the American Water Resources Association, 54(1): 28-39, 2018. Summary: This study explores methods that identify the scale where networks obtained by different methods agree within some margin of error. The problem is relevant for comparing hydrologic models built around the two networks.
  • ElSadaani, M., W.F. Krajewski, R. Goska, and M. Smith, An investigation of errors in the NFIE-Hydro frameworks’ stream discharge prediction due to channel routing, Journal of the American Water Resources Association, 54(1), 1-10, 2018. Summary: The authors substitute RAPID which is based on the simplified linear Muskingum routing method by the nonlinear routing component the Iowa Flood Center have incorporated in their full hydrologic Hillslope‐Link Model. The results show improvement in model performance across scales due to incorporating new routing methodology.
  • ElSadaani, M., W.F. Krajewski, and D.L. Zimmerman, River network based characterization of errors in remotely sensed rainfall products in hydrological applications, Remote Sensing Letters, 9(8), 743–752, 2018. Summary: The results show that the magnitudes of the rainfall discrepancies tend to decrease as rainfall accumulates in the downstream direction. However, the covariance range between these discrepancies is much larger along flow-connected stream network segments than in flow-unconnected stream segments. This in turn could have an effect on the error correlation of the predicted discharges. In addition, the spatial linear models of rainfall errors improved significantly with SSN based models in comparison to pure Euclidean separation distance models.
  • Ghimire, G.R., W.F. Krajewski, and R. Mantilla, A power law model for river water velocity in U.S. Upper Midwestern basins, Journal of the American Water Resources Association, 54(3), 1-13, 2018. Summary: This study explores power law relationships to estimate water flow velocity as a function of discharge and drainage area across river networks. We test the model using empirical data from 214 United States (U.S.) Geological Survey gauging stations distributed over the state of Iowa in the U.S.
  • Seo, B.-C., F. Quintero, and W.F. Krajewski, High-resolution QPF uncertainty and its implications for flood prediction: A case study for the Eastern Iowa flood of 2016, Journal of Hydrometeorology, 19(8), 1289–1304, 2018. Summary: This study addresses the uncertainty of High-Resolution Rapid Refresh (HRRR) quantitative precipitation forecasts (QPFs), which were recently appended to the operational hydrologic forecasting framework. In this study, we examine the uncertainty features of HRRR QPFs for an Iowa flooding event that occurred in September 2016.
  • Quintero, F., R. Mantilla, C. Anderson, D. Claman, and W.F. Krajewski, Assessment of changes in flood frequency due to the effects of climate change: Implications for engineering design, Hydrology, 5, 19, 1-16, doi:10.3390/hydrology5010019, 2018. Summary: The authors explore the uncertainty implied in the estimation of changes in flood frequency due to climate change at the basins of the Cedar River and Skunk River in Iowa, United States. The study focuses on the influence of climate change on the 100-year flood, used broadly as a reference flow for civil engineering design.
  • Perez, G., R. Mantilla, and W.F. Krajewski, The influence of spatial variability of width functions on regional peak flow regressions. Water Resources Research, 54, 1-19. https://doi.org/10.1029/2018WR023509, 2018. Summary: The authors investigated the relation between the width function and the regional variability of peak flows. The authors explored 34 width function descriptors (WFDs), in addition to drainage area, as potential candidates for explaining the regional peak flow variability.
  • Seo, B.-C., W.F. Krajewski, F. Quintero, M. ElSaadani, R. Goska, L.K. Cunha, B. Dolan, D.B. Wolff, J.A. Smith, S.A. Rutledge, and W.A. Petersen, Comprehensive evaluation of the IFloodS radar-rainfall products for hydrologic applications, Journal of Hydrometeorology, 19(11), 1793–1813, 2018. Summary: This study describes the generation and testing of a reference rainfall product created from field campaign datasets collected during the NASA Global Precipitation Measurement (GPM) mission Ground Validation Iowa Flood Studies (IFloodS) experiment. The study evaluates ground-based radar rainfall (RR) products acquired during IFloodS in the context of building the reference rainfall product.
  • Perez, G., R. Mantilla, and W.F. Krajewski, Estimating annual and monthly scale-invariant flow duration curves for the State of Iowa, Journal of Hydrologic Engineering,23(12): 05018021, 2018. Summary: This paper presents a procedure to derive historical-annual and historical-monthly flow duration curves (FDC) that are monotonic and continuous for agricultural, unregulated, ungauged sites. The authors explore the performance and the regional dependence of four different regression models for the estimation of daily flow quantiles (QpQp), with probabilities of exceedance (pp) ranging from 0.01 to 0.99.
  • Varmaghani, A., Eichinger, W. E., & Prueger, J. H. (2018). Modification of FAO Penman-Monteith Equation for Minor Components of Energy. Hydrology Research, 50(2), In Press. doi: 10.2166/nh.2018.093. Summary: The findings in this study suggest a fundamental modification of FAO P-M formula by considering the inclusion of MECs in the energy term.
  • Ayalew, T.B., W.F. Krajewski, R. Mantilla, and D.L. Zimmerman, Can floods at large river basin be predicted from floods observed at small subbasins? Journal of Flood Risk Management, 1-8, DOI: 10.1111/jfr3.12327, 2017. Summary: In this article, we show that a log‐linear relationship between α(e) and θ(e) can be used to simplify the problem of predicting α(e) and θ(e) from the physical characteristics of the catchment and rainfall. In particular, we show that α(e) can be predicted from peak floods observed in the smallest gauged subcatchment in the basin and its log‐linear relationship with θ(e) can be used to predict peak flood at any location in the basin. We demonstrate this using observed peak floods from the Iowa River basin in the Upper Midwest part of United States.
  • Chen, B., W.F. Krajewski, R. Goska, and N. Young, Using LiDAR surveys to document floods: A case study of the 2008 Iowa flood, Journal of Hydrology, 553, 338-349, 2017. Summary: Can we use Light Detection and Ranging (LiDAR), an emergent remote sensing technology with wide applications, to document floods with high accuracy? To explore the feasibility of this application, we propose a method to extract distributed inundation depths from a LiDAR survey conducted during flooding.
  • Dhanya, C.T., and G. Villarini, An investigation of predictability dynamics of temperature and precipitation in reanalysis datasets over the continental United States, Atmospheric Research, 183, 341-350, 2017. Summary: Reanalysis datasets have been under critical scrutiny due to their widespread use in various climatic and hydrological modeling applications, in particular over many areas of the globe with limited or absent reliable observational data.
  • Nayak, M.A, and G. Villarini, A long-term perspective of the hydroclimatological impacts of atmospheric rivers over the central United States, Water Resources Research, 53, 1144-1166, 2017. Summary: The focus of this study is on the climatology of atmospheric rivers (ARs) over the central United States using six atmospheric reanalysis products. This climatology is used to understand the long‐term impacts of ARs on annual precipitation, precipitation extremes, and flooding over the central United States.
  • Zhang, W., and G. Villarini, On the unseasonal flooding over the central United States during December 2015 and January 2016, Atmospheric Research, 196, 23-28, 2017. Summary: The unseasonal winter heavy rainfall and flooding that occurred during December 2015–January 2016 had large socio-economic impacts for the central United States. Here we examine the climatic conditions that led to the observed extreme precipitation, and compare and contrast them with the 1982/1983 and 2011/2012 winters.
  • Mallakpour, I., G. VillariniM.P. Jones, and J.A. Smith, On the use of Cox regression to examine the temporal clustering of flooding and heavy precipitation across the central United States, Global and Planetary Change, 155, 98-108, 2017. Summary: The findings of this work highlight that variations in the climate system play a critical role in explaining the occurrence of flood and heavy precipitation events at the sub-seasonal scale over the central United States.
  • Zhang, W., G. Villarini, E. Scoccimarro, and G.A. Vecchi, Stronger influences of increased CO2 on sub-daily precipitation extremes than at the daily scale, Geophysical Research Letters, 44, 7464-7471, 2017. Summary: We find that the increased CO2 concentration substantially increases the odds of the occurrence of subdaily precipitation extremes compared to the daily scale in most areas of the world, with the exception of some regions in the subtropics, likely in relation to the subsidence of the Hadley Cell. These results point to the large role that atmospheric CO2 plays in extreme precipitation under an idealized framework.
  • Villarini, G., A. Khouakhi, and E. Cunningham, On the impacts of computing daily temperatures as the average of the daily minimum and maximum temperatures, Atmospheric Research, 198, 145-150, 2017. Summary: Daily temperature values are generally computed as the average of the daily minimum and maximum observations, which can lead to biases in the estimation of daily averaged values. This study examines the impacts of these biases on the calculation of climatology and trends in temperature extremes at 409 sites in North America with at least 25 years of complete hourly records. Our results show that the calculation of daily temperature based on the average of minimum and maximum daily readings leads to an overestimation of the daily values of ~ 10+ % when focusing on extremes and values above (below) high (low) thresholds.
  • Salvi, K., G. Villarini, and G.A. Vecchi, High resolution decadal precipitation predictions over the continental United States for impacts assessment, Journal of Hydrology, 553, 559-573, 2017. Summary: Here, we focus on nine GCMs and quantify the seasonally and regionally averaged skill in DPPs over the continental United States. We address the problems pertaining to the limited skill and resolution by applying linear and kernel regression-based statistical downscaling approaches.
  • Slater, L.J., and G. Villarini, Evaluating the drivers of seasonal streamflow in the U.S. Midwest, Water, 9(9), 1-22, 2017. Summary: Streamflows have increased notably across the U.S. Midwest over the past century, fueling a debate on the relative influences of changes in precipitation and land cover on the flow distribution. Here, we propose a simple modeling framework to evaluate the main drivers of streamflow rates.
  • Mallakpour, I., and G. Villarini, Analysis of changes in the magnitude, frequency, and seasonality of heavy precipitation over the contiguous United States, Theoretical and Applied Climatology, 130, 345-363, 2017. Summary: Gridded daily precipitation observations over the contiguous USA are used to investigate the past observed changes in the frequency and magnitude of heavy precipitation, and to examine its seasonality. Analyses are based on the Climate Prediction Center (CPC) daily precipitation data from 1948 to 2012.
  • Salvi, K., G. Villarini, G.A. Vecchi, and S. Ghosh, Decadal temperature predictions over the continental United States: Analysis and enhancement, Climate Dynamics, 49, 3587-3604, 2017. Summary: Here, we focus on 14 GCMs and evaluate seasonally and regionally averaged skills in DTPs over the continental United States. Moreover, we address the limitations in skill and spatial resolution in the GCM outputs using two data-driven approaches: (1) quantile-based bias correction and (2) linear regression-based statistical downscaling.
  • Zhang, W., and G. Villarini, Extreme precipitation is highly sensitive to the magnitude of future warming, Climatic Change, 145, 249-257, 2017. Summary: Here, we investigate the changes in heavy precipitation events with the Community Earth System Model (CESM) climate experiments using the scenarios consistent with the 1.5 and 2 °C temperature targets. We find that the frequency of annual heavy precipitation at a global scale increases in both 1.5 and 2 °C scenarios until around 2070, after which the magnitudes of the trend become much weaker or even negative.
  • Krajewski, W.F., Ceynar, D., Demir, I., Goska, R., Kruger, A., Langel, C., Mantilla, R., Niemeier, F., Quintero, F., Seo, B.C., Small, S., Weber, L., Young, N., Real-Time Flood Forecasting and Information System for the State of Iowa, Bulletin of the American Meteorological Society, 98, 539–554, 2017. Summary: The system complements the operational forecasting issued by the National Weather Service, is based on sound scientific principles of flood genesis and spatial organization, and includes many technological advances. At its core is a continuous rainfall–runoff model based on landscape decomposition into hillslopes and channel links.
  • Demir, I., Szczepanek, R., Optimization of River Network Representation Data Models for Web-based Systems, Earth and Space Science, Volume 4, Issue 6, 2017. Summary: This paper presents a detailed study of widely used methods for representing generic networks in relational databases and benchmarking common queries on river network data using these methods.
  • L. Weber, M. Muste, A. A. Bradley, A.A Amado, I. Demir, C. Drake, W. Krajewski, T. Loeser, M. Politano, B. Shea, N. Thomas. The Iowa Watersheds Project: Iowa’s prototype for engaging communities and professionals in watershed hazard mitigation. International Journal of River Basin Management. DOI: 10.1080/15715124.2017.1387127, 2017. Summary: After more than a century of intensive changes in the state’s agricultural watersheds, repeated record floods motivated Iowa to innovate in its flood recovery and disaster mitigation efforts following the 2008 floods. The state created the Iowa Flood Center (IFC) and authorized the creation of Watershed Management Authorities.
  • Jones, C.S.; Nielsen, J.K.; Schilling, K.E.; and Weber, L.J. 2018. “Iowa Stream Nitrate and the Gulf of Mexico,” PLoS ONE, 13, 4, e0195930, 2018. Summary: Mississippi, Missouri, and Iowa stream nitrate loads quantified, 1999–2016.
  • Drake, C.W.; Jones, C.S.; Schilling, K.E.; Arenas Amado, A.; and Weber, L.J. 2018. “Estimating Nitrate Retention in a Large Constructed Wetland Using High-Frequency, Continuous Monitoring and Hydrologic Modeling,” Ecological Engineering, 117, pp. 69–83, 2018. Summary: Nitrate reduction capacity quantified for constructed wetland using high-frequency in-situ sensor data and hydrological modeling.
  • Schilling, K.E.; Haines, B.J.; Jones, C.S.; and St. Clair, M. 2018. “Effectiveness of a Newly-Reconstructed Floodplain Oxbow to Reduce NO3-N Loads from a Spring Flood,” Journal of Environmental Management, 2015, pp. 385–393, 2018. Summary: Nitrate reduction capacity quantified for restored oxbow in Linn County (Iowa) park.
  • Jones C.S.; Kim S-W.; Wilton T.; Schilling K.E.; and Davis C.A. 2018. “Nitrate uptake in an agricultural stream estimated from high-frequency, in-situ sensors,” Environmental Monitoring and Assessment, 190 (4), April 2018. Summary: Real-time, continuous, in-situ water-quality sensors were deployed on a fourth-order Iowa (U.S.) stream draining an agricultural watershed to evaluate key in-stream processes affecting concentrations of nitrate during a 24-day late summer (Aug–Sep) period.
  • Jones, C.S., Davis, C.A., Drake, C.W., Schilling, K.E., Debionne, S.H., Gilles, D.W., Demir, I., and Weber, L.J. “Iowa Statewide Stream Nitrate Load Calculated Using In-Situ Sensor Network,” JAWRA Journal of the American Water Resources Association, 2018. Summary: High-frequency, in-situ nitrate sensors were strategically deployed across the agricultural state of Iowa to evaluate 2016 stream concentrations at 60 sites and loads at 35 sites.
  • Schilling, K.E.; Kim, S.-W.; Jones, C.S.; and Wolter, C.F. “Orthophosphorus Contributions to Total Phosphorus Concentrations and Loads in Iowa Agricultural Watersheds,” Journal of Environmental Quality, 46, 828–835, 2017. Summary: Portion of total phosphorus sourced to dissolved phosphorus quantified in Iowa streams.
  • Amado, A.A.; Schilling, K.E.; Jones, C.S.; Thomas, N.; and Weber, L.J. “Estimation of Tile Drainage Contribution to Streamflow and Nutrient Loads at the Watershed Scale Based on Continuously Monitored Data,” Environmental Monitoring and Assessment, 189, 426, 2017. Summary: The authors quantify the portion of stream nitrate originating from field drainage tiles.
  • Schilling, K.E.; Jones, C.S.; Wolter, C.F.; Zhang, Y.-K.; Liang, X.; Seeman, A.; Isenhart, T.; Schnoebelen, D.; and Skopec, M. “Variability of Nitrate-N Load Estimation Results Will Make Quantifying Load Reduction Strategies Difficult in Iowa,” Journal of Soil and Water Conservation, 72, pp. 315–323, 2017. Summary: Errors associated with nitrate estimation models indicate regular water monitoring is necessary to accurately characterize Iowa stream nitrate loads.
  • Schilling, K.E.; Kim, S-W.; and Jones, C.S. “Use of Water-Quality Surrogates to Estimate Total Phosphorus Concentrations in Iowa Rivers,” Journal of Hydrology, Regional Studies, 12, pp. 111–121, 2017. Summary: The relation of total phosphorous concentrations to the easy-to-monitor surrogates of turbidity, chloride, o-phosphorous, and discharge is derived.
  • Jones, C.S.; Wang, B.; Schilling, K.E.; and Chan, K-S. “Nitrate Transport and Supply Limitations Quantified Using High-frequency Stream Monitoring and Turning Point Analysis,” Journal of Hydrology, 549, pp. 581–591, 2017. Summary: High-frequency nitrate sensor data is used to quantify the relative importance of landscape nitrogen supply and discharge, and how each drives stream nitrate levels.
  • Hernandez, O.E.; Schnoebelen, D.J.; Papanicolaou, A.N.; and Abban, B. “Coupling Flow with Nutrient Dynamics via BioChemFOAM in the Mississippi River,” Journal of Applied Water Engineering and Research, 2017. Summary: The research introduce a new three-dimensional model called BioChemFOAM to study nutrient dynamics or species transport in aquatic ecosystems that can be adapted to different parameterizations and different hydrodynamic conditions from laminar to turbulent flow.
  • Jones, C.; Kim, S.W.; and Schilling, K. “Use of Continuous Monitoring to Assess Stream Nitrate Flux and Transformation Patterns,” Environmental Monitoring and Assessment, 2017 Jan 1, 189, 1:35. Summary: IIHR researchers use continuous nitrate sensors in the IWQIS network to assess how and why nitrate concentrations change within a stream.
  • Schilling, K.E.; Jones, C.S.; Wolter, C.F.; Zhang, Y-K.; Liang, X.; Seeman, A.; Isenhart, T.; Schnoebelen, D.; and Skopec, M. “Variability of Nitrate-N Load Estimation Results Will Make Quantifying Load Reduction Strategies Difficult in Iowa,” Journal of Soil and Water Conservation, accepted for publication, 2016. Summary: Researchers from several institutions assess nitrate load estimation methods and their practicality for measuring progress toward goals outlined by Iowa’s Nutrient Reduction Strategy.
  • Schilling, K.E.; Jacobson, P.J.; Streeter, M.T.; and Jones, C.S. 2016. “Groundwater Hydrology and Quality in Drained Wetlands of the Des Moines Lobe in Iowa,” Wetlands, 1-13. Summary: Groundwater hydrology and quality is assessed in eight drained wetlands in the prairie pothole region of Iowa.
  • Villarini, G.; Jones, C.S.; and Schilling, K.E. “Soybean Area and Baseflow Driving Nitrate in Iowa’s Raccoon River,” Journal of Environmental Quality, 45, 1949–1959, 2016. Summary: Development of statistical models to describe how nitrate concentrations change over time in the Raccoon River. Results show soybean area and baseflow (river discharge between storm events) to be important drivers of nitrate levels.
  • Villarini G.; Schilling K.E.; and Jones C.S. “Assessing the Relation of USDA Conservation Expenditures to Suspended Sediment Reductions in an Iowa Watershed,” Journal of Environmental Management, 180, 375-83, 2016. Summary: Long-term, high-frequency river sediment data is linked to USDA expenditures on conservation to evaluate how technical and financial assistance to farmers improves water quality.
  • Jones, C.S.; Seeman, A.; Kyveryga, P.; Schilling, K.E.; Kiel, A.; Chan, K-S.; and Wolter, C. “Crop Rotation and Raccoon River Nitrate,” Journal of Soil and Water Conservation, 71, 206-219, 2016. Summary: Long-term tributary dataset, along with farm management data, shows soybean area to be important driver of Raccoon River nitrate. Nitrate levels relatively stable or declining modestly from 1999–2014.
  • Jones, C.S. and Kult, K. “Use Alkalinity Monitoring to Optimize Bioreactor Performance,” Journal of Environmental Quality, 45, 855-865, 2016. Summary: Water monitoring strategies for assessing performance of de-nitrifying woodchip bioreactors, and important practice for the Iowa Nutrient Reduction Strategy.
  • Liang, X.; Schilling, K.; Zhang, Y.K.; and Jones, C. “Co-kriging Estimation of Nitrate-Nitrogen Loads in an Agricultural River,” Water Resources Management, 30, 1771–1784, 2016. Summary: Development of an effective mathematical method (Co-kriging) for estimating daily nitrate loads in a large Midwestern river.
  • Hansen, E.; Chan, K-S.; Jones, C.S.; and Schilling, K.E. “Assessing the Relative Importance of Nitrogen-retention Processes in a Large Reservoir Using Time-series Modeling,” Journal of Agricultural, Biological, and Environmental Statistics, 21, 152–169, 2016. Summary: Use of time-series modeling to estimate how much nitrate is retained and removed from the Des Moines River by Saylorville Reservoir.
  • Mishra, K.V.,  W.F. Krajewski, R. Goska, D. Ceynar, B.-C. Seo,  A. Kruger, J. Niemeier, M.B. Galvez, M. Thurai, V.N. Bringi, L. Tolstoy, P. Kucera, W. Petersen, J. Grazioli and A. Pazmany. “Deployment and Performance Analyses of High-resolution Iowa XPOL Radar System During the NASA IFloodS Campaign,” Journal of Hydrometeorology, 17, 2, 455–479, 2016. http://journals.ametsoc.org/doi/abs/10.1175/JHM-D-15-0029.1 Summary: This article presents the data collected and analyzed using the University of Iowa’s X-band weather radars that were part of the spring 2013 Iowa Flood Studies (IFloodS) field campaign, sponsored by the NASA’s Global Precipitation Measurement (GPM) satellite mission.
  • Renolds, K.N.; Loecke, T.D.; Burgin, A.J.; Davis, C.A.; Riveros-Iregui, D.; Thomas, S.A.; St. Clair, M.A.; and Ward, A.S. “Optimizing Sampling Strategies for Riverine Nitrate Using High-frequency Data in Agricultural Watersheds,” Environmental Science & Technology, May 18, 2016. Summary: Understanding linked hydrologic and biogeochemical processes such as nitrate loading to agricultural streams requires an understanding of the sampling bias and precision of monitoring strategies. Our results suggest that time-interval sampling most efficiently characterized all nitrate parameters, except at coarse frequencies for nitrate flux.
  • Streeter, M.T. and K.E. Schilling. “A Comparison of Soil Properties Observed in Farmed, Restored, and Natural Closed Depressions on the Des Moines Lobe of Iowa,” Catena, 129:39 015–45, 2015. Summary: This study quantified alterations of wetland soils due to artificial drainage by comparing soil properties at farmed, restored, and natural sites in the Des Moines Lobe region of Iowa.
  • Schilling, K.E.; P.J. Jacobson; and J. Vogelgesang. “Agricultural Conversion of Floodplain Ecosystems: Implications for Groundwater Quality,” Journal of Environmental Management, 153:74–83, 2015. Summary: In this study, groundwater hydrology and nutrient dynamics associated with three floodplain land cover types were assessed at the Cedar River floodplain in southeast Iowa.
  • Liang, X.; Y.K. Zhang; and E. Schilling. “Analytical Solutions for Two-dimensional Groundwater Flow with Subsurface Drainage Tiles,” Journal of Hydrology, 521:556–564, 2015. Summary: Analytical solutions for groundwater level and discharge were derived and used to compare hydrologic conditions in a system with and without tile (natural drainage).
  • Liang, X.; Y.K.Zhang; and E. Schilling. “Temporal Variation of Groundwater Level in Heterogeneous Bounded Aquifer,” Stochastic Environmental Research and Risk Assessment, 1–8, 2015, DOI 10.1007/s00477-014-0990-4. Summary: In this study, analytical solutions for the variance and covariance of groundwater level were derived with nonstationary spectral analyses and superposition principle.
  • Schilling, K.E.; R. Anderson; C. Alexander; D. Peate; and J. Dorale. “Mining Unique Soft and Old Water within the Manson Impact Structure,” Hydrogeology Journal, 23:95–103, 2015. Summary: This study reported on groundwater quality and age in bedrock wells located in and around the town of Manson, Iowa. The City of Manson lies near the center of the Manson Impact Structure, a 37-km diameter impact crater formed about 74 million years ago.
  • McLellan, E.; D. Robertson; K.E. Schilling; M. Tomer; J. Kostel; D. Smith; and K. King. “Reducing Nitrogen Export from the Corn Belt to the Gulf of Mexico: Agricultural Strategies for Remediating Hypoxia,” Journal of the American Water Resources Association, 51:263–289, 2015. Summary: Modeling results from SPARROW were used to evaluate nitrate load reduction practices to remediate hypoxia in the Gulf of Mexico.
  • Schilling, K.E. and P. Jacobson. “Field Observation of Diurnal Dissolved Oxygen Fluctuations in Shallow Groundwater,” Groundwater, 53:493–497, 2015. Summary: In this study, we used an optical DO probe to measure rapid changes in concentration due to plant-groundwater interaction at an alluvial aquifer field site in Iowa.
  • Schilling, K.E. and P. Jacobson. “Temporal Variations in Dissolved Oxygen Concentrations in a Shallow Floodplain,” River Research and Applications, 31:576–589, 2015. Summary: We examined daily DO concentrations in a shallow floodplain setting in Iowa to quantify fluctuations across two growing seasons and examine hydrologic controls on DO values.
  • Ikenberry, C.D.; M.L. Soupir; K.E. Schilling; C.S. Jones; and A. Seaman. “Nitrate-nitrogen Export: Magnitude and Pattern from Drainage Districts to Downstream River Basins,” Journal of Environmental Quality, 43:2024–2033, 2014. Summary: Hydrology and export of nitrate from three drainage districts over a five-year period were quantified and reported in this study.
  • Ettema, R. and Nakato, T. “John Fisher Kennedy — Student and Statesman of Hydraulic Engineering,” Journal of Hydraulic Research, 52, 6, pp. 731–743, October 2014. Summary: John Fisher Kennedy had a remarkably accomplished career in hydraulic engineering. Though alluvial river behavior was the hydraulics topic closest to his heart, Kennedy also made scholarly contributions in the areas of river thermal and ice processes, the design and operation of thermal- and hydro-power plants, and various hydraulic structures. We reflect upon Kennedy’s work and the qualities that made him a prominent engineer and educator.
  • Denniston, R.F.; Villarini, G.; Gonzales, A.N.; Wyrwoll, K.H.; Polyak, V.J.; Ummenhofer, C.C.; Lachniet, M.S.; Wannamaker, A.D.; Humphreys, W.F.; Woods, D.; and Cugley, J. “Extreme rainfall activity in the Australian tropics reflects changes in the El Niño/Southern Oscillation over the last two millennia,” Proceedings of the National Academy of Sciences of the United States of America, 2015 (in press). Summary: Researchers applied a novel technique to stalagmites from the Australian tropics to create a 2,200-year-long record of flood events that might also help predict future climate change.
  • Kim, D.; Muste, M.; and Merwade, V. “A GIS-based Relational Data Model for Multi-dimensional Representation of River Hydrodynamics and Morphodynamics,” Environmental Modelling & Software, 65, 2015, pp. 79–93. Summary: This paper describes a new river data model (Arc River) that can be populated with both measured and simulated river data to facilitate descriptions of river features and processes using hydraulic/hydrologic terminology. Arc River is built in close connection with the existing Arc Hydro data model developed for water-related features to ensure the connection of the river characteristics with their floodplains and watersheds.
  • Schilling, K.E.; Wolter, C.F.; and McLellan, E. “Agro-hydrologic Landscapes in the Upper Mississippi and Ohio River Basins,” Environmental Management, December 2014.
  • Villarini, G.Goska, R.; Smith, J.A.; and Vecchi, G.A. “North Atlantic Tropical Cyclones and U.S. Flooding,” Bulletin of the American Meteorological Society, 95(9), 1381–1388, 2014. Summary: This study examines the relationship between North Atlantic tropical cyclones and flooding over the continental United States.
  • Vecchi, G.A.; Delworth, T.; Gudgel, R.; Kapnick, S.; Rosati, A.; Wittenberg, A.; Zeng, F.; Anderson, W.; Balaji, V.; Dixon, K.; Jia, L.; Kim, H.-S.; Krishnamurthy, L.; Msadek, R.; Stern, W.F.; Underwood, S.D.; Villarini, G.; Yang, X.; and Zhang, S. “On the Seasonal Forecasting of Regional Tropical Cyclone Activity,” Journal of Climate, 27, 7994–8016, 2014. Summary: This study examines the capability of a newly developed high-resolution global climate model to skillfully forecast seasonal tropical cyclone activity on spatial scales finer than basinwide, months and seasons in advance of the tropical cyclone season.
  • Davis, C.A.; Ward, A.S.; Burgin, A.J.; Loecke, T.D.; Riveros-Iregui, D.A.; Schnoebelen, D.J.; Just, C.L.; Thomas, S.A.; Weber, L.J.; and St. Clair, M.A. “Antecedent Moisture Controls on Stream Nitrate Flux in an Agricultural Watershed,” Journal of Environmental Quality, 43:1494–1503, 2014. Summary: This research investigated the effect of flood/drought periods on in-stream nitrate dynamics in an agricultural watershed. Results show significant differences in nitrate concentration and load attributed to variations in dominant flow pathways and water sources during wet/dry cycles.
  • Chaney, N.W.; Sheffield, J.; Villarini, G.; and Wood, E.F. “Development of a High-resolution Gridded Daily Meteorological Data Set over Sub-Saharan Africa: Spatial Analysis of Trends in Climate Extremes,” Journal of Climate, 27(15), pp. 5815–5835, 2014. Summary: It examines changes in climate extremes (temperature and precipitation) over the Sub-Saharan Africa during the period 1979–2005.
  • Nayak, M.A.; Villarini, G.; and Lavers, D.A. “On the Skill of Numerical Weather Prediction Models to Forecast Atmospheric Rivers over the Central United States,” Geophysical Research Letters, 41, pp. 4354–4362, 2014. Summary: This study focuses on the verification of the skill of five numerical weather prediction models in forecasting atmospheric river (AR) activity over the central United States. We find that these models generally forecast AR occurrences well at short lead times, with location errors increasing from one to three decimal degrees as the lead time increases to about one week. The skill (both in terms of occurrence and location errors) decreases with increasing lead time. Overall, these models are not skillful in forecasting AR activity over the central United States beyond a lead time of about seven days.
  • Ferguson, C.R. and Villarini, G.An Evaluation of the Statistical Homogeneity of the 20th-Century Reanalysis,” Climate Dynamics, 42(11-12), pp. 2841-2866, 2014. Summary: This article focuses on the evaluation of the 20th-century reanalysis at the global scale.
  • Muste, M.; Hauet, A.; Fujita, I.; Legout, C.; and Ho, H.-C. “Capabilities of Large-Scale Particle Image Velocimetry to Characterize Shallow Free-Surface Flows,” Advances in Water Resources, 70(2014), pp. 160–171, 2014.
  • Villarini, G.; Lavers, D.A.; Scoccimarro, E.; Zhao, M.; Wehner, M.F.; Vecchi, G.A.; Knutson, T.R.; and Reed, K.A. “Sensitivity of tropical cyclone rainfall to idealized global scale forcings,” Journal of Climate, 27(12), pp. 4622–4641, 2014. Summary: This paper uses a set of idealized high-resolution atmospheric model experiments produced as part of the U.S. Climate Variability and Predictability (CLIVAR) Hurricane Working Group activity to examine the response of rainfall associated with tropical cyclones to idealized global-scale perturbations: the doubling of CO2, uniform 2-K increases in global, and their combined impact.
  • Scoccimarro, E.; Gualdi, S.; Villarini, G.; Vecchi, G.A.; Zhao, M.; Walsh, K.; and Navarra, A. “Intense precipitation events associated with landfalling tropical cyclones in response to a warmer climate and increase CO2,” Journal of Climate, 27(12), pp. 4642–4654, 2014. Summary: This paper investigates possible changes in the intensity of rainfall events associated with tropical cyclones under idealized forcing scenarios, including a uniformly warmer climate, with a special focus on landfalling storm.
  • Wright, D.B.; Smith, J.A.; Villarini, G.; and Baeck, M.L. “Long-term high-resolution radar rainfall fields for urban hydrology,” Journal of the American Water Resources Association, 50(3), pp. 713–34, 2014. Summary: Explores the development of a long-term (10-year) high-resolution (15-minute and 1-km) radar-based rainfall dataset for Charlotte, N.C.
  • Goodwin, R.A.; Politano, M.Garvin, J.W.; Nestler, J.M.; Hay, D.; Anderson, J.J.; Weber, L.J.; Dimperio, E.; Smith, D.L.; and Timko, M. “Fish navigation of large dams emerges from their modulation of flow field experience.” Summary: To understand fish movement through hydropower dam environments, we combine a computational fluid dynamics model of the flow field at a dam and a behavioral model in which simulated fish adjust swim orientation and speed to modulate their experience to water acceleration and pressure (depth).
  • Villarini, G. and Strong, A. Roles of climate and agricultural practices in discharge changes in an agricultural watershed in Iowa.” Agriculture, Ecosystems and Environment. 188, pp. 204-211, 2014.
  • Demir, I. and Krajewski, W.F. Towards an Integrated Flood Information System: Centralized data access, analysis, and visualization.” Environmental Modelling & Software, 50, pp. 77-84, 2013. Summary: This paper provides an overview of the design and capabilities of the Iowa Flood Information System (IFIS) which is developed as a platform to provide one-stop access to flood-related information.
  • Varmaghani, A. and Ghiassi, R. “Release Time Component of a Hydrograph.” Journal of Hydrologic Engineering, 19(2), pp. 444-447, 2014.
  • Varmaghani, A.An Analytical Formula for Potential Water Vapor in Atmosphere of Constant Lapse Rate.” Terrestrial, Atmospheric and Oceanic Sciences, 23(1), pp. 17-24, 2012.
  • Odgaard, A.J.; Lyons, T.C.; and Craig, A.J. “Baffle-Drop Structure Design Relationships.” Journal of Hydraulic Engineering, 139(9), pp. 995-1002, 2013. Summary: The study is part of an effort to optimize the design of drop structures for transfer of storm and wastewater to deep underground tunnels. Drop structures and tunnels are used in large metropolitan areas, where space is limited and surface runoff is nearly 100 percent. The tunnels provide temporary storage of the combined wastewater before it is pumped to treatment plants and released to waterways. Air entrainment and release is a major design variable.
  • Schilling, K.E. and Drobney, P. “Restoration of prairie hydrology at the watershed scale: two decades of progress at Neal Smith National Wildlife Refuge.” Land, 3, pp. 206-238, 2014. Summary: Understanding hydrologic processes at the watershed scale has been the focus of research at Neal Smith NWR for nearly two decades and the paper reports on the progress made on restoring key hydrologic components, including the water balance, stream network, hydrograph, groundwater levels and water quality.
  • Schilling, K.E. and Jacobson, P. “Effectiveness of perennial riparian buffers to reduce subsurface nutrient losses to incised streams in southern Iowa.” Catena, 114, pp. 140-148, 2014. Summary: Perennial vegetation lines many incised streams in Iowa and is assumed to provide a natural riparian buffer.  In this study we evaluated groundwater nutrient concentrations beneath four different riparian land covers and note that despite lower water tables and oxidizing conditions near the channel, the natural buffer vegetation reduces nutrient levels.
  • Palmer, J.A.; Schilling, K.E.; Isenhart, T.M.; and Schultz, R.C. “Streambank erosion rates and loads with a single watershed: bridging the gap between temporal and spatial scales.” Geomorphology, 209, pp. 66-78, 2014. Summary: The importance of streambank erosion is increasingly recognized and in this study we report on bank erosion patterns and rates monitored over a seven-year period in the Walnut Creek watershed.
  • Schilling, K.E.; McLellan, E.; and Bettis, E.A. “Letting wet spots be wet: restoring natural bioreactors in the dissected glacial landscape.” Environmental Management, 52, pp. 1440-1452, 2014. Summary: In this paper we argue that there is tremendous potential for nitrate-N reductions to occur throughout the dissected glaciated Midwest if we simply let naturally occurring wet spots on the landscape remain wet.
  • Schilling, K.E.; Jones, C.S.; and Seamon, A. “How paired is paired? Comparing nitrate concentrations in three Iowa drainage districts.” Journal of Environmental Quality, 42, pp. 1412-1421, 2013.
  • Li, D.; Chan, K.S.; and Schilling, K.E. Nitrate concentration trends in Iowa’s rivers, 1998 to 2012: What challenges await nutrient reduction initiatives?Journal of Environmental Quality, 42, pp. 1822-1828, 2013. Summary: In this study, we analyzed trends in nitrate-N concentrations in 60 ambient river sites in Iowa for the years 1998-2012 and found that while most (80%) did not show a significant trend, six sites in western Iowa show an increasing trend ranging from 0.15 to 0.33 mg/l per year.
  • Villarini, G., and Strong, A. “Roles of Climate and Agricultural Practices in Discharge Changes in an Agricultural Watershed in Iowa.” Agriculture, Ecosystems, and Environment, 2014. Summary: This article focuses on the Raccoon River at Van Meter, Iowa, and on the entire discharge distribution, from minimum to maximum discharge and everything in between. It uses statistical models to explain the changes in discharge in terms of changes in rainfall and agricultural practices since 1927.
  • Lavers, D.A. and Villarini, G. Were Global Numerical Weather Prediction Systems Capable of Forecasting the Extreme Colorado Rainfall of 9–16 September 2013?Geophysical Research Letters, 40(24), pp. 6405–6410, 2013.
  • Czajkowski, J.; Villarini, G.; Michel-Kerjan, E.; and Smith, J.A. “Determining Tropical Cyclone Inland Flooding Loss on a Large Scale through a New Flood Peak Ratio-Based Methodology.” Environmental Research Letters, 4, 2013. Summary: Modeling of insurance claims associated with flooding from Hurricane Ivan.
  • Hajimirzaie, S.M. and Buchholz, J.H.J. Flow Dynamics in the Wakes of Low-Aspect-Ratio Wall-Mounted Obstacles.” Experiments in Fluids, 54, p. 1616, 2013. Summary: In a previous paper, we documented the influence of shape and relative submergence (the ratio of flow depth to obstacle height) on the mean flow around low-aspect-ratio wall-mounted semi-ellipsoids, which was chosen as a broad representative of a freshwater mussel projecting from a river bed. We examined the shedding characteristics and dynamics of the wake. A model of the arch vortex dynamics was proposed and confirmed to explain the observed streamwise vorticity distributions in the ellipsoid wakes.
  • Lavers, D.A. and Villarini, G.Atmospheric Rivers and Flooding over the Central United States.” Journal of Climate, 26, pp. 7829–7836, 2013. Summary: This paper examines the relation between atmospheric rivers (ARs) and flooding over the central United States during the period 1979-2011. ARs are regions of enhanced atmospheric water vapor transport in the lower troposphere. They play a large role in the global water cycle, and are associated with a large number of flood events over the central United States.
  • Knutson, T.R.; Sirutis, J.J.; Vecchi, G.A.; Garner, S.; Zhao, M.; Kim, H.-S.; Bender, M.; Tuleya, R.E.; Held, I.M.; and Villarini, G. Dynamical Downscaling Projections of Late 21st-Century Atlantic Hurricane Activity: CMIP3 and CMIP5 Model-Based Scenarios.” Journal of Climate, 26(17), pp. 6575–6590, 2013. Summary: In this work, we examine the robustness of potential changes in North Atlantic hurricane activity using 21st-century projections of Atlantic climate.
  • Villarini, G. and Smith, J.A. “Flooding in Texas: Examination of Temporal Changes and Impacts of Tropical Cyclones.” Journal of the American Water Resources Association, 49(4), pp. 825–837, 2013. Summary: We examined annual maximum peak discharge time series from 62 stations in Texas with a record of at least 70 years. This work focuses on examination of changes in flood magnitude over the 20th and 21st centuries and on the role played by tropical cyclones as flood agent. The results of this research indicate that most of the changes in the flood peak records are associated with human modifications of the watersheds (e.g., river regulation) and that tropical cyclones are not associated with the largest flood events to the same degree that was found for the eastern United States.
  • Lavers, D.A. and Villarini, G.The Nexus Between Atmospheric Rivers and Extreme Precipitation across Europe.” Geophysical Research Letters, 40(12), pp. 3259–3264, 2013. Summary: Extreme precipitation and floods in Europe are a recurring natural hazard causing large socioeconomic damages. Here we investigate the connection between annual maxima (AM) daily precipitation at a pan-European scale and atmospheric rivers (ARs), narrow filaments that convey the majority of the poleward water vapor transport within extratropical cyclones. We show that ARs are responsible for many AM precipitation days in Western Europe. The relationship is especially strong along the western European seaboard, with some areas having eight of their top 10 AM related to ARs. The effects of ARs are also seen as far inland as Germany and Poland. Southern Europe was most affected by ARs under negative North Atlantic Oscillation (NAO) conditions, whereas northern Europe was more associated with a positive relationship between ARs and an NAO-type pattern. Our results suggest that ARs are critical in explaining the upper tail of the extreme precipitation distribution in Western Europe.
  • Villarini, G.; Scoccimarro, E.; and Gualdi, S. “Projections of Heavy Rainfall over the Central United States Based on CMIP5 Models.” Atmospheric Science Letters, 14(3), pp. 200–205, 2013. Summary: This study is about the examination of changes in extreme rainfall over the central United States. It is based on daily data obtained from 20 state-of-the-art coupled global climate models and one scenario. We examined the projected changes in the 90th and 99th percentiles of the daily rainfall distribution over the current century. The results point to an increase in extreme rainfall over large areas of the central United States.  Moreover, the comparison between the projected changes in the 90th and 99th percentiles points to stronger trend in the latter. This suggests that extreme rainfall is projected to become more extreme, consistent with the redistribution toward more intense rainfall observed in the observational record over the recent past.
  • Lavers, D.A.; Allan, R.P.; Villarini, G.; Lloyd-Huges, B.; Brayshaw, D.J.; and Wade, A.J. “Future Changes in Atmospheric Rivers and Their Implications for Winter Flooding in Britain.” Environmental Research Letters, 8(3), pp. 1–8, 2013.
  • Vecchi, G.A.; Msadek, R.; Anderson, W.; Chang, Y.-S.; Chang, T.; Delworth, T.; Dixon, K.; Gudgel, R.; Rosati, A.; Stern, W.; Villarini, G.; Wittenberg, A.; Yang, X.; Zeng, F.; Zhang, R.; and Zhang, S. “Multi-Year Predictions of North Atlantic Hurricane Frequency: Promise and Limitations.” Journal of Climate, 26(15), pp. 5337–5357, 2013. Summary: This paper is about multi-year predictability of North Atlantic hurricanes. While there is encouraging retrospective forecast skill, it highlights that care should be used in interpreting the results because of the short record, climate shifts, and changes in the observing system.
  • Peterson, T.C.; Heim, R.R.; Hirsch, R.; Kaiser, D.P.; Brooks, H.; Diffenbaugh, N.S.; Dole, R.M.; Giovannettone, J.P.; Guirguis, J.; Karl, T.R.; Katz, R.W.; Kunkel, K.; Lettenmaier, D.; McCabe, G.J.; Paciorek, C.J.; Ryberg, K.R.; Schubert, S.; Silva, V.B.S.; Stewart, B.C.; Vecchia, A.V.; Villarini, G.; Vose, R.S.; Walsh, J.; Wehner, M.; Wolock, D.; Wolter, K.; Woodhouse, C.A.; and Wuebbles, D. “Monitoring and Understanding Changes in Heat Waves, Cold Waves, Floods and Droughts in the United States: State of Knowledge.” Bulletin of the American Meteorological Society, 94(6), pp. 821-834, 2013. Summary: Provides a summary of the state of knowledge and understanding of long-term changes in heat and cold waves, floods, and droughts in the United States.
  • Smith, B.K.; Smith, J.A.; Baeck, M.L.; Villarini, G.; and Wright, D.B. “The Spectrum of Storm Event Hydrologic Response in Urban Watersheds.” Water Resources Research, 49(5), pp. 2649-2663, 2013. Summary: The study examines flood-producing rainfall properties and storm event hydrologic response for nine small watersheds in the Baltimore region including seven urbanized basins, a forested basin, and an agricultural basin. We find expected contrasts in flood peak distributions and storm event runoff production between the urban and nonurban watersheds, but we also find a spectrum of storm event hydrologic response among the urban watersheds.
  • Long, Y.; Villarini, G.; Smith, J.A.; Tian, F.; and Hu, H. “Changes in Seasonal Maximum Daily Precipitation in China over the Period 1961–2006.” International Journal of Climatology, 33(7), pp. 1646–1657, 2013. Summary: Daily rainfall data from 485 stations in China over the period 1961–2006 are used to examine changes in seasonal extreme rainfall. We focus on the temporal changes in their distribution, together with examination of the dependence of seasonal extreme rainfall on elevation.
  • Villarini, G. and Vecchi, G.A. “Multi-Season Lead Forecast of the North Atlantic Power Dissipation Index (PDI) and Accumulated Cyclone Energy (ACE).” Journal of Climate, 26, 11, pp. 3631–3643, 2013. Summary: This study focuses on the seasonally-integrated North Atlantic Power Dissipation Index (PDI) and the Accumulated Cyclone Energy (ACE). These are concise metrics routinely used to assess tropical storm activity by accounting for storm frequency, intensity, and duration. We have developed a hybrid statistical-dynamical seasonal forecasting system for North Atlantic PDI and ACE over the period 1982–2011, and we have shown that it is skillful in making forecasts from November of the previous year. That is, skillful predictions of the seasonally integrated North Atlantic tropical cyclone activity for the coming season could be made even while the current one is still underway.
  • Villarini, G. and Vecchi, G.A. “Projected Increases in North Atlantic Tropical Cyclone Intensity from CMIP5 Models.” Journal of Climate, 26(10), pp. 3231–3240, 2013. Summary: This study focuses on the projections in North Atlantic Power Dissipation Index (PDI), using output from 17 state-of-the-art global climate models and three radiative forcing scenarios. PDI is a metric accounting for intensity, frequency, and duration of tropical cyclones. Overall, we find that North Atlantic PDI is projected to increase with respect to the 1986–2005 period across all scenarios. The difference between the PDI projections and those of the number of North Atlantic tropical cyclones, which are not projected to increase significantly, indicates an intensification of North Atlantic tropical cyclones in response to both greenhouse gas increases and aerosol changes over the current century.
  • Ho, H-C.; Muste, M.; and Ettema, R. “Sediment Self-cleaning Multi-box Culverts.” Journal of Hydraulic Research, 51(1), pp. 92-101, 2013. Summary: Filed investigations of culvert sites and surveys of road maintenance personnel reveal that sedimentation is a widespread problem for multi-box culverts in Iowa and neighboring U.S. Midwest states. The study presents design considerations for mitigating the sedimentation at multi-box culverts using the sediment transport capacity of culvert-approach flow.
  • Rowe, S.T. and Villarini, G. Flooding associated with predecessor rain events over the Midwest United States.” Environmental Research Letters, 8, pp. 1-5, 2013. Summary: This article examines the severity and extent of flooding associated with six predecessor rain events (PREs) over the central United States. PREs are areas of heavy rainfall that occur about 1000 km ahead of landfalling tropical cyclones. We show that heavy rainfall and flooding associated with PREs occur well inland in non-tropical cyclone-prone locations. PREs can trigger annual maximum peak discharge at numerous stream gauge stations, causing flooding on the order of and in excess of the 10-year flood. Many large Midwestern cities (e.g., Chicago, Detroit) are especially susceptible to these events.
  • Wright, D.B.; Smith, J.A; Villarini, G.; and Baeck, M.L. “Estimating the Frequency of Extreme Rainfall Using Weather Radar and Stochastic Storm Transposition.” Journal of Hydrology, 488, pp. 150–165, 2013. Summary: This study presents an alternate framework to conventional design storms for rainfall frequency analysis. We demonstrate that extreme rainfall can vary substantially in time and in space, with potentially important flood risk implications that cannot be assessed using conventional techniques.
  • Villarini, G. and Smith, J.A. “Spatial and Temporal Variability of Cloud-to-Ground Lightning Over the Continental U.S. during the Period 1995–2010,” Atmospheric Research, 124, pp. 137–148, 2013. Summary: We examined the spatial and temporal variability of major lightning days over the continental United States from 1995–2010. The central United States exhibits statistically significant increasing trends, while we see a general tendency toward decreasing trends over the Rocky Mountains. These results raise the question of whether the observed changes in lightning activity during the recent years are related to natural or human-induced changes in the climate system, and/or to inhomogeneities in the observational network.
  • Stanier, C.O.; Singh, A.; Adamski, W.; Baeck, J.; Caughey, M.; Carmichael, G.R.; Edgerton, E.; Kenski, D.; Koerber, M.; Oleson, J.; Rohlf, T.; Lee, S.R.; Riemer, N.; Shaw, S.; Sousan, S.; and Spak, S.Overview of the LADCO Winter Nitrate Study: Hourly Ammonia, Nitric Acid, and PM2.5 Composition at an Urban and Rural Site Pair During PM2.5 Episodes in the U.S. Great Lakes Region,” Atmospheric Chemistry and Physics, 12, pp. 1–12, 2012.
  • Villarini, G.; Smith, J.A.; Vitolo, R.; and Stephenson, D.B. “On the Temporal Clustering of U.S. Floods and Its Relationship to Climate Teleconnection Patterns.” International Journal of Climatology, 33(3), pp. 629–640, 2013. Summary: This article examines whether the occurrence of flood events should be considered independently of each other, or clustered in time. If floods cluster, then the fact that one event has occurred changes the chances of another event to occur later. The authors analyzed data from 41 stream gauge stations in Iowa, with discharge records covering the period 1950–2009. The results point to clustering as an important element of the analysis of flood occurrence. The authors discuss the possible physical mechanisms responsible for the observed clustered behavior in terms of climate variability and land-surface processes.
  • Lyons, T.Craig, A.; and Weber, L.J. “Experimental Model Study for the Design of a Spillway Gate to Reduce TDG Production at a Hydropower Dam.” Hydrovision, 2013.
  • Villarini, G.; Smith, J.A.; Baeck, B.K.; and Sturdevant-Rees, P. “Hydrologic Analyses of the 17–18 July 1996 Flood in Chicago and the Role of Urbanization.” Journal of Hydrologic Engineering, 18(2), pp. 250–259, 2013. Summary: This study focuses on the July 17–18, 1996 event that caused record rainfall in northeastern Illinois. We examine the capability of the Davenport weather radar to estimate heavy rainfall at far range, and perform a series of hydrologic analyses to understand the role of land use/land cover and rainfall variability for such an extreme event. The results of this study indicate that urbanization played a major roles in the hydrologic response for the study watersheds.
  • Villarini, G. and Vecchi, G.A. “Multi-Season Lead Forecast of the North Atlantic Power Dissipation Index (PDI) and Accumulated Cyclone Energy (ACE).” Journal of Climate, 2012. Summary: Here we focus on the Power Dissipation Index (PDI) and the Accumulated Cyclone Energy (ACE). These are concise metrics routinely used to assess tropical storm activity by accounting for storm frequency, intensity and duration. We have developed a hybrid statistical-dynamical seasonal forecasting system for North Atlantic PDI and ACE over the period 1982–2011, and showed that it is skillful at making forecasts from November of the previous year. That is, skillful predictions of the seasonally integrated North Atlantic tropical cyclone activity for the coming season could be made even while the current season is still underway.
  • Villarini, G. and Vecchi, G.A. “Projected Increases in North Atlantic Tropical Cyclone Intensity from CMIP5 Models.” Journal of Climate, 2012. Summary: Here we focus on the projections in North Atlantic PDI using output from 17 state-of-the-art global climate models and three radiative forcing scenarios. Overall, we find that North Atlantic PDI is projected to increase with respect to the 1986–2005 period across all scenarios. The difference between the PDI projections and those of the number of North Atlantic tropical cyclones, which are not projected to increase significantly, indicates an intensification of North Atlantic tropical cyclones in response to both greenhouse gas increases and aerosol changes over the current century.
  • Zhai, G.Lehmler, H.-J.; and Schnoor, J.L. Sulfate Metabolites of 4-Monochlorobiphenyl in Whole Poplar Plants.” Environmental Science & Technology, 47, pp. 557−562, 2013.
  • Zhai, G.; Lehmler, H-J.; and Schnoor, J.L. “Inhibition of Cytochromes P450 and the Hydroxylation of 4-Monochlorobiphenyl in Whole Poplar.” Environmental Science & Technology, 2013.
  • Rim, Y.; McPherson, D.D.; Chandran, K.B.; and Kim, H. “The Effect of Patient-Specific Annular Motion on Dynamic Simulation of Mitral Valve Function.” Journal of Biomechanics, 2013.
  • Chandran, K.B. and Vigmostad, S. “Patient-Specific Bicuspid Valve Dynamics and Valvular and Ascending Aortic Pathology: An Overview of Methods and Challenges.” Journal of Biomechanics, 46, pp. 208–216, 2013.
  • Sugumaran, R. and Thomas, J. Semi-Analytical Model for the Multi-Temporal Prediction of Chlorophyll-a in an Iowa Lake Using Hyperion Data.” Photogrammetric Engineering and Remote Sensing, 78(12), pp. 1253–1260, 2012. Summary: The aim of this study was to use an analytical approach to monitor water quality in an Iowa lake using multi-temporal Hyperion satellite imagery.
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Posted on January 29th, 2013

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