HR: 08:45h
AN: A21B-02    [Abstracts]
TI: Seasonal and Interannual Variations of Global Precipitation In the NCEP CDAS, CDAS2, GFS and CFS
AU: * Xie, P
EM: Pingping.Xie@noaa.gov
AF: Climate Prediction Center/NOAA/NWS, 5200 Auth Rd., Room# 605, Camp Springs, MD 20746 United States
AU: Janowiak, J E
EM: John.Janowiak@noaa.gov
AF: Climate Prediction Center/NOAA/NWS, 5200 Auth Rd., Room# 605, Camp Springs, MD 20746 United States
AU: Chen, M
EM: Mingyue.Chen@noaa.gov
AF: RSIS/Climate Prediction Center/NOAA/NWS, 5200 Auth Rd., Room#605, Camp Springs, MD 20746 United States
AU: Arkin, P A
AF: ESSIC, University of Maryland, University of Maryland, College Park, MD United States
AB: Seasonal and interannual variations of global large-scale precipitation generated by the NCEP CDAS, CDAS2, GFS AMIP runs and CFS free runs have been examined and compared with those in the CMAP data set. The mean annual cycle of monthly precipitation is defined for a 23-year period from 1979 to 2001 for the CDAS, CDAS2, GFS AMIP runs and the CMAP, and for the first 32 years of free run periods for the CFS. In general, the mean annual cycles of CDAS, CDAS2, GFS and CFS are consistent with the observations, especially over the Pacific Ocean. Certain consistent errors, however, are observed. The ITCZ is too weak in CDAS and too strong in the GFS. Over the Atlantic, the ITCZ in the CDAS, CDAS2 and CFS displaced southward during December - May, while that in the GFS AMIP runs located in the same places as in the observations but presents excessive rainfall especially over the western ocean. Interannual variability of precipitation associated with the ENSO, NAO, AO and PNA is then investigated for the data periods. ENSO composite anomalies are fairly realistic, although the GFS appears too intense. NAO/AO composite anomalies from CDAS/CDAS2/GFS/CFS are quite good in the North Atlantic, while they are less realistic near and south of the equator. To further understand the model performance, oceanic boundary condition and atmospheric circulation fields associated with the seasonal and interannual variations of precipitation are examined. Detailed results will be reported at the meeting.
DE: 3309 Climatology (1620)
DE: 3354 Precipitation (1854)
SC: Atmospheric Sciences [A]
MN: 2005 Joint Assembly