scholarly journals Break of the Western North Pacific Summer Monsoon in Early August

2015 ◽  
Vol 28 (8) ◽  
pp. 3420-3434 ◽  
Author(s):  
Ke Xu ◽  
Riyu Lu
Keyword(s):  
Summer Monsoon ◽  
North Pacific ◽  
Western North Pacific ◽  
Asian Summer Monsoon ◽  
The Other ◽  
South Asian Summer Monsoon ◽  
Close Link ◽  
Rainfall Reduction ◽  
Asian Summer ◽  
Asian Monsoons

Abstract Although the monsoon break is a well-known phenomenon for the South Asian summer monsoon, it has not been well documented for the other monsoons, for instance, the western North Pacific (WNP) summer monsoon. This study identified a distinct monsoon break over the WNP by analyzing the subseasonal evolution of atmospheric convection and precipitation. This WNP monsoon break occurs climatologically in early August (3–8 August), but shows a strong variation, in either intensity or timing, from year to year. For about 30% of years, the rainfall amount reduces by more than 10 mm day−1 over the northeast WNP (10°–20°N, 140°–160°E) in early August, and is even less than that before the monsoon onset. However, for the other 30% of years, the subseasonal evolution of rainfall tends to be out of phase with the climatology, and rainfall reduction appears in mid-August. Furthermore, the 10–25-day oscillations, which originate at the equatorial western Pacific and propagate northwestward, are found to play a crucial role in forming the monsoon break. The 10–25-day oscillations exhibit a strong interannual variation, associated with the WNP monsoon trough during the period from late July to mid-August, and contribute greatly to the year-to-year variation in both the timing and intensity of the monsoon break. Considering the close link in subseasonal evolution between the WNP and East Asian monsoons, the present results indicate the necessity to investigate the possible role of the WNP monsoon break on the weather and climate over East Asia.

scholarly journals Global Extratropical Response to Diabatic Heating Variability of the Asian Summer Monsoon

2009 ◽  
Vol 66 (9) ◽  
pp. 2697-2713 ◽  
Author(s):  
Hai Lin
Keyword(s):  
Summer Monsoon ◽  
Indian Summer Monsoon ◽  
North Pacific ◽  
Western North Pacific ◽  
Large Scale ◽  
Asian Summer Monsoon ◽  
Convective Activity ◽  
Mean Flow ◽  
Asian Summer ◽  
Circulation Anomalies

Abstract Global teleconnections associated with the Asian summer monsoon convective activities are investigated based on monthly data of 29 Northern Hemisphere summers defined as June–September (JJAS). Two distinct teleconnection patterns are identified that are associated respectively with variabilities of the Indian summer monsoon and the western North Pacific summer monsoon. The Indian summer monsoon convective activity is associated with a global pattern that has a far-reaching connection in both hemispheres, whereas the western North Pacific summer monsoon convective activity is connected to a Southern Hemisphere wave train that influences the high-latitude South Pacific and South America. A global primitive equation model is utilized to assess the cause of the global circulation anomalies. The model responses to anomalous heatings of both monsoon systems match the general features of the observed circulation anomalies well, and they are mainly controlled by linear processes. The response patterns are largely determined by the summertime large-scale background mean flow and the location of the heating anomaly relative to the upper easterly jet in the monsoon region.

Spring Arctic Oscillation-East Asian summer monsoon connection through circulation changes over the western North Pacific

2011 ◽  
Vol 37 (11-12) ◽  
pp. 2199-2216 ◽  
Author(s):  
Dao-Yi Gong ◽  
Jing Yang ◽  
Seong-Joong Kim ◽  
Yongqi Gao ◽  
Dong Guo ◽  
...  
Keyword(s):  
Summer Monsoon ◽  
North Pacific ◽  
East Asian Summer Monsoon ◽  
Western North Pacific ◽  
Arctic Oscillation ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Asian Summer ◽  
Circulation Changes

scholarly journals Impact of the Southeast Asian summer monsoon strength on the outflow of aerosols from South Asia

2010 ◽  
Vol 28 (1) ◽  
pp. 277-287 ◽  
Author(s):  
L. Zhang ◽  
H. Liao ◽  
J. Li
Keyword(s):  
South Asia ◽  
Summer Monsoon ◽  
North Pacific ◽  
Western North Pacific ◽  
Southern China ◽  
Asian Summer Monsoon ◽  
Southeast Asian ◽  
The South ◽  
Asian Summer ◽  
Monsoon Strength

Abstract. We chose a relatively weak Southeast Asian summer monsoon (SEASM) year (1998) and a relatively strong year (2002) to examine the impact of the monsoon strength on the transport of organic carbon (OC) aerosol emitted from the South Asia (75°–105° E, 10°–25° N) by using the global 3-D chemical transport model GEOS-Chem driven by the assimilated meteorological fields. Simulated surface layer concentrations and column burdens of OC indicate that OC levels are much higher in the weak SEASM year 1998 than in the strong SEASM year 2002. The sensitivity experiments with global OC emissions turned off except those over the South Asia show that OC aerosol emitted from South Asia contributes to 50–70% of OC mass over southern China and 20–50% of OC over the western North Pacific between 850 hPa and 400 hPa in 1998. The outflow of OC from the South Asia is larger in 1998 than in 2002. Three factors contribute to the larger buildup of summer time OC in the weak SEASM year of 1998. The first is the weakened summer monsoon rainfall over the Southeast Asia that leads to less wet deposition and higher OC concentrations. The second is the enhancement of deep convection in the western Indian continent and the weakened upward lifting over the western North Pacific. The last and the most important factor is the abnormal circulation in the lower and middle troposphere that contributes to the long-range transport of OC from South Asia to Southern China and the western North Pacific.

Deficiencies and possibilities for long-lead coupled climate prediction of the Western North Pacific-East Asian summer monsoon

2010 ◽  
Vol 36 (5-6) ◽  
pp. 1173-1188 ◽  
Author(s):  
Sun-Seon Lee ◽  
June-Yi Lee ◽  
Kyung-Ja Ha ◽  
Bin Wang ◽  
Jae Kyung E. Schemm
Keyword(s):  
Summer Monsoon ◽  
North Pacific ◽  
East Asian Summer Monsoon ◽  
Western North Pacific ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Climate Prediction ◽  
Asian Summer

scholarly journals Role of tropical cyclones over the western North Pacific in the East Asian summer monsoon system

2019 ◽  
Vol 3 (2) ◽  
pp. 147-156 ◽  
Author(s):  
Xian Chen ◽  
◽  
Zhong Zhong ◽  
YiJia Hu ◽  
Shi Zhong ◽  
...  
Keyword(s):  
Tropical Cyclones ◽  
Summer Monsoon ◽  
North Pacific ◽  
East Asian Summer Monsoon ◽  
Western North Pacific ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Monsoon System ◽  
Asian Summer

Enhanced tropospheric biennial oscillation of the East Asian summer monsoon since the late-1970s

2021 ◽  
pp. 1-54
Author(s):  
Wen Chen ◽  
Kaiming Hu ◽  
Shangfeng Chen
Keyword(s):  
Summer Monsoon ◽  
North Pacific ◽  
East Asian Summer Monsoon ◽  
Western North Pacific ◽  
El Nino ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Tropospheric Biennial Oscillation ◽  
Asian Summer ◽  
Biennial Oscillation

Abstract The tropospheric biennial oscillation (TBO) of East Asian summer monsoon (EASM) has major impacts on East Asian climate. Here it is shown that, since the late-1970s, the TBO signal of EASM has strengthened significantly. The EASM TBO in wind anomalies undergoes a transition from a cyclone over the western North Pacific (WNPC) in preceding summer to an anticyclone over the western North Pacific (WNPAC) in following summer, with the anomalies strengthening remarkably after the late-1970s. Correspondingly, the biennial component of precipitation anomalies in eastern China show different distributions. Both observational and numerical simulation analyses demonstrate that these changes are caused by the westward shift of El Niño warming and enhanced Indo-Pacific and Atlantic-Pacific coupling. The positive sea surface temperature (SST) anomalies associated with the TBO of EASM shift toward the central Pacific after the late-1970s, which favor the strengthening of the WNPC and cause a weakened EASM. In following summer, both the north Indian Ocean and tropical north Atlantic SST warming are closely coupled with El Niño since the late-1970s, which favor the strengthening of WNPAC and cause an intensified EASM. Together, these changes provide more favorable background state for the transition of circulation anomalies over the western North Pacific, giving rise to enhanced biennial variability in EASM in the late-1970s.

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