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October 25, 2001
The experiment is in its second year. In the Fall of 2000, early in the field campaign several of our instruments failed and we never managed to bring them to working condition during the time frame of the experiment. During the Spring and Summer of 2001 we regrouped, fixed the equipment and got ready for the second attempt. We will continue through early December.
We deployed five disdrometers in an area that is the size of one pixel (about 1 km by 1.5 km) of the Davenport, Iowa WSR-88D (80 kilometers east of Iowa City). Two of the disdromters come from France, courtesy of Dr. Dominique Creutin and his French colleagues. These are optical devices that measure light shadowing by raindrops. They measure drop size and velocity. A POSS disdrometer was loaned to us by the McGill University Radar Observatory, courtesy of Dr. Isztar Zawadzki. The instruments works like a mini radar. It converts the Doppler spectrum into the drop size distribution. It works especially well when there is no significant wind. A Joss-Waldvogel impact disdrometer was loaned to us by Dr. Fred Ogden from the University of Connecticut. We had to replace the original unit with a refurbished one by the manufacturer. The fifth disdrometer is our own two-dimensional video device (2DVD).
At the end of September the X-POW radar arrived from Florida where it was used in NASA's CAMEX campaign. We deployed the radar some 10 km west of Iowa City. The radar is functioning very well, we collected data for several events. We are scanning mainly RHIs over the rain gauge cluster at the Iowa City Municipal Airport and the disdrometers. We also scan 180 degree sector for surveillance purposes.
Collocated with the 2DVD is the University of Iowa Mobile Rainfall Observatory that includes a vertically-pointing X-band Doppler radar (VPRDX). We managed to fix the radar about two weeks ago and collected data in concert with other instruments. We are making arrangements for the radar calibration. We will calibrate the VPRDX against the X-POW by flying an airplane above both.
Check other links in our website for maps, pictures, and plots of data collected thus far.
November 9, 2000
During the first week of the experiment we deployed all the instruments in the field. The NOA X-POL (which we also call X-POW) is setup 10 km west of the Iowa City Airport. The Iowa Mobile Rainfall Observatory (IMRO), which consists of the vertically pointing X-band Doppler radar (X-VPRD) and the two-dimensional video disdrometer (2DVD), is setup at the Iowa City Airport. Four dual-gauge platforms collect data using tipping bucket rain gauges. These are situated at west and east outskirts of Iowa City, near a small town of Hills, and near a small town Riverside southeast of Iowa City. These complement the 11 dual-gage platforms we operate at the Iowa City Airport. We provided electric power to X-POW and IMRO from external sources (so that we don't have to use the noisy power generators).
Readiness of the instruments is mixed. The X-POW seems to operate fine and we are learning small quirks of the software and the hardware systems. We try to eliminate these glitches as we go. Through an inadvertent mistake we seem to have damaged a control board on the 2DVD. We are waiting for a replacement part. The X-VPRD works intermittently and we have difficulty collecting data. We have contacted radar engineers and enlisted their help to resolve the situation soon. The gauges work fine.
We had two rainfall events during the first week. The first one, on November 1 was insignificant with total rain of less than 2 mm. The second one, on November 6, lasted almost 20 hours and we collected plenty of X-POW data. We are analyzing the data now and getting ready for the next event forecasted for November 12.
During the experiment the entire group meets every day at 9:00 for logistics and weather briefings. After division of tasks, the group members remain in frequent contact through cell phones, e-mail and personal interactions.
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Please send comments
to: webmaster@iihr.uiowa.edu Contact us at: iihr@uiowa.edu or call 319-335-5237 Copyright © The University of Iowa 2005. All rights reserved. Iowa City, IA 52242 This page was last updated on November 19, 2009 |