Observing and Understanding the Variability of Water in Weather and Climate


Preliminary Results and Observations Gauging the Performance of the LAPS Water Vapor Analysis During IHOP


Daniel L Birkenheuer, NOAA/ERL/FSL, Boulder, CO

The Local Analysis and Prediction System (LAPS) analyzes three-dimensional state variables each hour over a user-selected domain. This past spring, it was operated in conjunction with the International H2O Experiment (IHOP) centered near the ARM-CART site in central Kansas and Oklahoma. LAPS analyses routinely initialize local-scale high-resolution models such as NCAR's MM5 (mesoscale model, version 5). The LAPS system has been integrated into the AWIPS system as part of the National Weather Service modernization.

We are now studying the quality of the 4-km LAPS water vapor analyses with the detailed observations from IHOP. In particular we are interested in the ability of LAPS using operational datasets such as NESDIS/GOES special products of layer precipitable water and cloud-top pressure, GVAR sounder radiances, GPS, and Oklahoma Mesonet surface dewpoint observations, to render the water vapor environment. This assessment will be performed by validating against "special" IHOP data that include frequent and closely spaced dropsondes, aircraft measurements, and ground based lidar and cloud radar data gathered for IHOP and later quality controlled. Of particular interest is the degree to which a current analysis scheme with "operational" quality data can describe the moisture environment. Special emphasis will be placed on which new datasets offer the most potential for operational application, and which of the current "operational" datasets appear vital to water vapor diagnosis for local-scale analysis and forecast application. Modeled quantitative precipitation forecasts based on these analyses will also be used to gauge analysis utility.

Session 1, International H2O Project (IHOP)
Monday, 10 February 2003, 10:45 AM-2:30 PM

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