Download
1 / 12
120 likes | 129 Views
This report provides an update on the recent evolution and current conditions of the Asian-Australian Monsoon System, as well as predictions for the upcoming weeks. It includes rainfall patterns over the past 90 days, 30 days, and 5 days, as well as atmospheric circulation patterns and NCEP/GFS model forecasts.
E N D
The Asian-Australian Monsoon System: Recent Evolution, Current Status and Prediction Update prepared by Climate Prediction Center / NCEP 20 April 2009 For more information, visit:http://www.cpc.ncep.noaa.gov/products/Global_Monsoons/Asian_Monsoons/Asian_Monsoons.shtml
Outline • Recent Evolution and Current Conditions • Monsoon Prediction • Summary • Climatology
Rainfall Patterns: Last 90 Days The CMAP dataset shows that, during the past 90 days, above-normal precipitation occurred over the tropical eastern Indian Ocean, southern South China Sea, the Philippine Sea, the Coral Sea, and much of the maritime continent. Precipitation was below normal over the Middle East, eastern India, southern China, Korea, Madagascar, Australia, and the subtropical central southern Indian Ocean.
Rainfall Patterns: Last 30 Days During the past 30 days, above-normal precipitation occurred over the tropical eastern Indian Ocean, northern maritime continent, the Coral Sea, and near Madagascar. Below-normal precipitation was observed over East Asia, Australia, Indonesia, New Guinea, tropical northwestern Pacific, and subtropical central-eastern southern Indian Ocean.
Rainfall Patterns: Last 5 Days During the past week, rainfall was above normal over the Bay of Bengal, tropical southern Indian Ocean (east of 65°E), and tropical far western Pacific (north of the Equator). It was below normal over New Guinea and Bangladesh.
Rainfall Time Seriesover 5x5 lat-lon boxes • *This unified land-only daily precipitation dataset is different from the CMAP dataset used in the previous three spatial maps. • Upper panel: Much of the Indo-China peninsula has experienced conditions of above-normal precipitation. • Middle and lower panels: Above-normal precipitation appeared over (northern) maritime continent when heavy monsoon rainfall shifted northward, leaving dry condition over northern Australia.
Atmospheric Circulation At the lower troposphere, anomalous cyclonic patterns were observed over the Bay of Bengal and northern South China Sea. Westerly flow was above normal over the tropical Indian Ocean and southern South China Sea. On the other hand, an anomalous anti-cyclonic pattern was observed to the east of the Philippines. These conditions favor an early onset of monsoon over Southeast Asia.
NCEP/GFS Model Forecasts Bias-Corrected Precip. Anom. for Week 1 & Week 2 Week-1 Week-2
Predictions of East Asia – NW Pacific Monsoon • Upper panel: East Asia – Western North Pacific (EAWNP) monsoon index (Wang et al. 2008) defined as U850 (5-15ºN, 40-80ºE) – U850 (20-30ºN, 70-90ºE). The NCEP Global Forecast System predicts that the EAWNP monsoon-type circulation will be stronger than normal in the next two weeks. • Lower panel: Correlation between precipitation and the East Asia – Western North Pacific monsoon index (Wang et al. 2008; shading) and regression of 850-mb winds on the monsoon index (vectors) for April.
Summary • During the past week, rainfall was above normal over the Bay of Bengal, tropical southern Indian Ocean (east of 65°E), and tropical far western Pacific (north of the Equator). It was below normal over New Guinea and Bangladesh. • The NCEP Global Forecast System predicts that the EAWNP monsoon-type circulation will be stronger than normal, with above-normal precipitation over the Indo-China peninsula and the Philippines, in the next two weeks. The model also predicts below-normal precipitation over southeastern China and western Indonesia.
