The Asian-Australian Monsoon
System: Recent Evolution,
Current Status and Prediction
Update prepared by
Climate Prediction Center / NCEP
April 19, 2010
For more information, visit:
http://www.cpc.ncep.noaa.gov/products/Global_Monsoons/Asian_Monsoons/Asian_Monsoons.shtml
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Outline
• Recent Evolution and Current Conditions
• Monsoon Prediction
• Summary
• Climatology
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Precip Patterns: Last 90 Days
During the past 90 days, precipitation over the Middle East, southern Asia, Southeast
Asia, northwestern Pacific, Madagascar, and southern-subtropical eastern Indian Ocean
was mainly below average. Above-average precipitation was observed over equatorial
eastern Indian Ocean, part of subtropical southern Indian Ocean, northeastern Australia,
and equatorial western Pacific Ocean.
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Precip Patterns: Last 30 Days
During the past 30 days, below-average precipitation was observed over the Middle
East, southern Asia, subtropical northwestern Pacific, Madagascar, and subtropical
southern Indian Ocean. Above-average precipitation was seen over Bangladesh, East
Asia, equatorial Southeast Asia, the tropical oceans especially eastern Indian Ocean
and western Pacific.
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Precip Patterns: Last 5 Days
In the past week, precipitation was mainly near normal over the Asian-Australian
region. Above-normal precipitation was observed over East Asia and below-
average precipitation was seen over the tropical-subtropical southern Indian
Ocean.
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Rainfall Time Series
over 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: In spite of the rainfalls since late March, the long-lasting
drought condition in southwestern China can still be seen clearly.
Middle panel: Dry condition has been founded over the Philippines
since the last winter.
Lower panel: Accumulated rainfall has been above average
continuously over western Indonesia during the past half year. 6
Atmospheric Circulation
The lower-tropospheric circulation over tropical Asian-Australian region
was mainly normal. Anomalously strong cross-equatorial flow was
observed over the Indian Ocean, and anomalous southwesterlies appeared
over the northern Indian Ocean and northern Bay of Bengal.
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NCEP/GFS Model Forecasts
Bias-Corrected Precip. Anom. for Weak 1 & Week 2
Week-1
Week-2
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Prediction 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). Positive (negative)
values indicate strong (weak) than normal
monsoon.
The NCEP Global Forecast System
predicts that, in the next two weeks,
the monsoon circulation over
Southeast Asia and northwestern
Pacific will be near normal.
Lower panel: Correlation between
rainfall and 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. Green (brown) shading
indicates increase (decrease) in rainfall
associated with strong monsoon. 9
Summary
• In the past week, precipitation was mainly near
normal over the Asian-Australian region. Above-
normal precipitation was observed over East
Asia and below-average precipitation was seen
over the tropical-subtropical southern Indian
Ocean.
• The NCEP Global Forecast System predicts that,
in the next two weeks, the monsoon circulation
over Southeast Asia and northwestern Pacific
will be near normal.
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Onset of the Asian Monsoon
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Climatology
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