scholarly journals Air–sea interaction and formation of the Asian summer monsoon onset vortex over the Bay of Bengal

2011 ◽  
Vol 38 (1-2) ◽  
pp. 261-279 ◽  
Author(s):  
Guoxiong Wu ◽  
Yue Guan ◽  
Yimin Liu ◽  
Jinghui Yan ◽  
Jiangyu Mao
Keyword(s):  
Summer Monsoon ◽  
Bay Of Bengal ◽  
Asian Summer Monsoon ◽  
Monsoon Onset ◽  
Summer Monsoon Onset ◽  
Asian Summer ◽  
Monsoon Onset Vortex

Isotopic Signal of Earlier Summer Monsoon Onset in the Bay of Bengal

2012 ◽  
Vol 25 (7) ◽  
pp. 2509-2516 ◽  
Author(s):  
Xiaoxin Yang ◽  
Tandong Yao ◽  
Wulin Yang ◽  
Baiqing Xu ◽  
You He ◽  
...  
Keyword(s):  
Summer Monsoon ◽  
Bay Of Bengal ◽  
Asian Summer Monsoon ◽  
Monsoon Onset ◽  
Monsoon Circulation ◽  
Abrupt Decrease ◽  
Vapor Source ◽  
Summer Monsoon Onset ◽  
Asian Summer ◽  
Precipitation Δ18o

Abstract The onset of the Asian summer monsoon is noticeably controversial, spatially and temporally. The stable oxygen isotope δ18O in precipitation has long been used to trace water vapor source, particularly to capture the summer monsoon precipitation signal. The abrupt decrease of precipitation δ18O in the Asian summer monsoon region closely corresponds to the summer monsoon onset. Two stations have therefore been set up at Guangzhou and Lulang in the East Asian summer monsoon domain to clarify the summer monsoon onset dates. Event-based precipitation δ18O during 2007/08 is much lower at Lulang than at Guangzhou and is attributable mainly to the altitude effect offset by different isotopic compositions in marine moisture sources. The earlier appearance of low δ18Owt at Lulang than at Guangzhou confirms the earlier summer monsoon onset in the Bay of Bengal. Isotopically identified summer monsoon evolutions from precipitation δ18O at both stations are verifiable with NCEP–NCAR reanalysis data, indicating that precipitation δ18O offers an alternative approach to studying the summer monsoon circulation from precipitation δ18O.

A Moist Entropy Budget View of the South Asian Summer Monsoon Onset

2019 ◽  
Vol 46 (8) ◽  
pp. 4476-4484
Author(s):  
Ding Ma ◽  
Adam H. Sobel ◽  
Zhiming Kuang ◽  
Martin S. Singh ◽  
Ji Nie
Keyword(s):  
South Asian ◽  
Summer Monsoon ◽  
Asian Summer Monsoon ◽  
Monsoon Onset ◽  
South Asian Summer Monsoon ◽  
The South ◽  
Summer Monsoon Onset ◽  
Asian Summer ◽  
Entropy Budget

scholarly journals Genesis of the South Asian High and Its Impact on the Asian Summer Monsoon Onset

2013 ◽  
Vol 26 (9) ◽  
pp. 2976-2991 ◽  
Author(s):  
Boqi Liu ◽  
Guoxiong Wu ◽  
Jiangyu Mao ◽  
Jinhai He
Keyword(s):  
South Asian ◽  
Summer Monsoon ◽  
Asian Summer Monsoon ◽  
Lower Troposphere ◽  
Monsoon Onset ◽  
South Asian High ◽  
The South ◽  
Subtropical Anticyclone ◽  
Summer Monsoon Onset ◽  
Asian Summer

Abstract The formation of the South Asian high (SAH) in spring and its impacts on the Asian summer monsoon onset are studied using daily 40-yr ECMWF Re-Analysis (ERA-40) data together with a climate-mean composite technique and potential vorticity–diabatic heating (PV–Q) analysis. Results demonstrate that, about 2 weeks before the Asian summer monsoon onset, a burst of convection over the southern Philippines produces a negative vorticity source to its north. The SAH in the upper troposphere over the South China Sea is then generated as an atmospheric response to this negative vorticity forcing with the streamline field manifesting a Gill-type pattern. Afterward, the persistent rainfall over the northern Indochinese peninsula causes the SAH to move westward toward the peninsula. Consequently, a trumpet-shaped flow field is formed to its southwest, resulting in divergence pumping and atmospheric ascent just over the southeastern Bay of Bengal (BOB). Near the surface, as a surface anticyclone is formed over the northern BOB, an SST warm pool is generated in the central–eastern BOB. This, together with SAH pumping, triggers the formation of a monsoon onset vortex (MOV) with strong surface southwesterly developed over the BOB. Enhanced air–sea interaction promotes the further development and northward migration of the MOV. Consequently, the wintertime zonal-orientated subtropical anticyclone belt in the lower troposphere splits, abundant water vapor is transported directly from the BOB to the subtropical continent, and heavy rainfall ensues; the atmospheric circulation changes from winter to summer conditions over the BOB and Asian summer monsoon onset occurs.

scholarly journals Principal condition for the earliest Asian summer monsoon onset

2002 ◽  
Vol 29 (15) ◽  
pp. 36-1-36-4 ◽  
Author(s):  
Shinjiro Kanae ◽  
Taikan Oki ◽  
Katumi Musiake
Keyword(s):  
Summer Monsoon ◽  
Asian Summer Monsoon ◽  
Monsoon Onset ◽  
Summer Monsoon Onset ◽  
Asian Summer
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