HR: 15:20h
AN: U23A-05    [Abstracts]
TI: Impact of Soundings Over Mexico on Regional Analyses
AU: * Mo, K C
EM: Kingtse.Mo@noaa.gov
AF: Climate Prediction Center, 5200 Auth Rd., Camp Springs, Md 20746, United States
AB: Data impact experiments were carried out to quantify the impact of soundings over Mexico on regional analyses using the Regional Climate Data Assimilation System (RCDAS) for the 2004 NAME Enhanced Observation Period (EOP). The period was chosen because the extensive set of observations and value added products are available for verification. Two experiments were performed and both withheld all soundings over Mexico. The experiment RCDASwt(p) assimilates observed precipitation, and the second experiment RCDASwt(no P) does not assimilate observed precipitation. Results from these experiments are compared with the operational RCDAS during the NAME 2004 EOP. The soundings in general improve the analyses over the areas where the assimilation system has the largest uncertainties and errors. Overall, the biggest impact of soundings can be found over Mexico. While differences at upper levels are small, the differences at lower levels are substantial. The impacts are larger if no precipitation is assimilated. The surface temperature is warmer over the central Mexico without soundings. The difference can be as large as about 1.5 C. Without soundings, there are more vertically integrated moisture convergence anomalies over Mexico. Without P assimilation to correct P, there are large differences in P. Overall, soundings over Mexico improve the quality of analysis over Mexico.
DE: 3315 Data assimilation
DE: 9350 North America
SC: Union [U]
MN: 2007 Joint Assembly