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Satellite Observations in Support of NAME Diagnostic Studies. Phil Arkin, ESSIC University of Maryland. Outline. Mean seasonal cycle in precipitation in the NAME region Seasonal and diurnal variability in precipitation in the NAME region during the 2003 monsoon season
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Satellite Observations in Support of NAME Diagnostic Studies Phil Arkin, ESSIC University of Maryland
Outline • Mean seasonal cycle in precipitation in the NAME region • Seasonal and diurnal variability in precipitation in the NAME region during the 2003 monsoon season • Issues for NAME Diagnostic Studies
Seasonal variability in precipitation in the NAME region from CMAP • CMAP is composite product using several satellite-derived estimates and gauge observations (Xie and Arkin, 1997) • Monthly, 2.5ºx 2.5º used here • Averaged over 1987 – 1997 (full dataset is 1979-2003)
CMAP Precipitation 1987 - 1997 April – June July - August Ratio – percentage increase from AMJ to JA
CMAP precipitation (1987-1997) for AMJ (top) and JA (bottom) Tip of Baja California goes from <0.2 to 2-3 mm/day; coastal point to the south goes from 1 to >6 mm/day
Ratio (JA/AMJ) Annual cycle of precipitation averaged over the two boxes
Details of the diurnal cycle during the 2003 monsoon season using CMORPH • CMORPH is composite product using all available passive microwave-derived estimates with interpolation by advection inferred from geostationary IR (Joyce et al., 2003, submitted) • Basic dataset is 30 minute/8 km – 3 hour totals for 0.25ºx 0.25º areas used here • Pingping Xie made the figures I will show here; thanks also to Robert Joyce, John Janowiak, Mingyue Chen and Yelena Yarosh
Conclusions: Part 4 • CMORPH allows us to visualize details of the influence of the terrain of the diurnal cycle of precipitation that probably have not been seen before • Precipitation dies away quickly to the west of the Sierra Madre Occidental; only a little rain makes it offshore • ITCZ south of Mexico has weak diurnal cycle with peak just after midnight; sharp demarcation right at coastline • Over the U.S., CMORPH exhibits clear eastward propagation from the Rockies, quite similar to Carbone et al. findings from several years of radar data
Issues for NAME Diagnostic Studies • Precipitation products that utilize satellite observations (such as, but not limited to, CMAP and CMORPH) will be very useful for NAME diagnostics studies: • However, the link to surface-based observations (gauges, radars) is still to be made for fine scales • The (likely) loss of TRMM and AMSR (on ADEOS-2) is a significant handicap