Iowa City Airport Piconet

Investigators

Witold Krajewski & Anton Kruger

Description

This high-density network of rain gauges has been established to collect information on small-scale rainfall variability. The main application of the collected data is in deriving the correlation structure of rainfall as a function of distance. This function is necessary to quantify errors of rainfall estimates obtained using weather radar. In the United States, radar-rainfall estimates obtained based on observations from the national network of the WSR-88D weather radars have resolution of about 4 km by 4 km. Accuracy of these estimates is typically based on comparisons with rain gauge data. As rain gauges have a much smaller sampling volume, for such comparisons to be meaningful, they have to take into account the natural variability of rainfall at the scale smaller than the radar product resolution (Ciach and Krajewski 1999). As the operational networks operated by the National Weather Service, the U.S. Corps of Engineers, and the Unites States Geological Survey have inter gauge distances much larger that the scale of the radar-rainfall products they do not provide the needed information. Thus, special purpose clusters of rain gauges are needed. Several such research clusters are being established around the country. These include Norman, Oklahoma and Guam in addition to the temporary experimental clusters deployed by NASA in Florida. To describe these small-scale clusters of rain gauges we coined the term "piconet" as the distances they cover are as small as 1-1000 m.

A unique element of our design is the duality of the sensors (see picture below). The two gauges are separated by about 1 m and this helps in early detection of many sensor malfunctioning problems. The Iowa City Airport cluster has 10 sites, each with two gauges. The collected data will be compared with rainfall estimates from the Davenport, Iowa WSR-88D located some 100 km due east. This project was supported with equipment grant from the Army Research Office. For other experimental research concerning rainfall keep exploring this web site or check Krajewski et al. (1999). For the rain gauge data from our piconet or copies of the above references please contact Witold Krajewski or Anton Kruger.

References

Ciach, J. G., and W. F. Krajewski, On the estimation of radar rainfall error variance, Advances in Water Resources, 22(6), 585-595, 1999.

Krajewski, W. F., A. Kruger, and V. Nešpor, Experimental and numerical studies of small-scale rainfall measurements and variability, Water Science and Technology, 37(11), 131–138, 1998.

Related Press

Article in Iowa City Press-Citizen, Monday, November 30, 1998 (news.pdf, 29K)