Relations of Water Vapor Transport from Indian Monsoon with That over East Asia and the Summer Rainfall in China

2001 ◽  
Vol 18 (5) ◽  
pp. 1005-1017 ◽  
Author(s):  
Zhang Renhe
2021 ◽  
pp. 1-54

Abstract It has been suggested that summer rainfall over Central Asia (CA) is significantly correlated with the summer thermal distribution of the Tibetan Plateau (TP) and the Indian summer monsoon (ISM). However, relatively few studies have investigated their synergistic effects of different distribution. This study documents the significant correlations between precipitation in CA and the diabatic heating of TP and the ISM based on the results of statistical analysis and numerical simulation. Precipitation in CA is is dominated by two water vapor transport branches from the south which are related to the two primary modes of anomalous diabatic heating distribution related to the TP and ISM precipitation, that is, the “+-” dipole mode in the southeastern TP and the Indian subcontinent (IS), and the “+-+” tripole mode in the southeastern TP, the IS, and southern India. Both modes exhibit obvious mid-latitude Silk Road pattern (SRP) wave trains with cyclone anomalies over CA, but with different transient and stationary eddies over south Asia. The different locations of anomalous anticyclones over India govern two water vapor transport branches to CA, which are from the Arabian Sea and the Bay of Bengal. The water vapor flux climbs while being transported northward and can be transported to CA with the cooperation of cyclonic circulation. The convergent water vapor and ascending motion caused by cyclonic anomalies favor the precipitation in CA. Further analysis corroborates the negative South Indian Ocean Dipole (NSIOD) in February could affect the tripole mode distribution of TP heating and ISM via the atmospheric circulation, water vapor transport and an anomalous Hadley cell circulation. The results indicate a reliable prediction reference for precipitation in CA.


2019 ◽  
Vol 32 (21) ◽  
pp. 7575-7594 ◽  
Author(s):  
Bo Sun ◽  
Huijun Wang ◽  
Botao Zhou

Abstract This study examined the interdecadal variations in the relationship between the East Asian water vapor transport (WVT) and the central and eastern tropical Pacific (CETP) sea surface temperatures (SSTs) in January during 1951–2018, focusing on the meridional WVT over East Asia, which is critical for the East Asian winter precipitation. The results indicate that before the 1980s, an increased southerly WVT over East Asia was generally associated with warm SST anomalies in the CETP during January, whereas, after the mid-1980s, an increased southerly WVT over East Asia was mostly associated with cold SST anomalies in the central tropical Pacific during January. The underlying mechanisms are discussed based on a comparison on the climate anomalies associated with the East Asian meridional WVT between the periods of 1951–79 and 1986–2018. During 1951–79, the meridional WVT over East Asia was mainly modulated by the Pacific–East Asian (PEA) teleconnection, which would induce an anomalous southerly WVT over East Asia corresponding to warm SST anomalies in the CETP. Whereas, during 1986–2018, the connection between the PEA teleconnection and the East Asian meridional WVT was weakened. The connection among the CETP SSTs, the anomalous zonal circulation over the North Pacific, and the East Asian meridional WVT was enhanced. Additionally, the connection among the CETP SSTs, the circumglobal teleconnection in the Northern Hemisphere, and the East Asian meridional WVT was enhanced. The above two enhanced connections opposed the effect of the PEA teleconnection and would induce an anomalous southerly WVT over East Asia corresponding to cold SST anomalies in the central tropical Pacific.


2019 ◽  
Vol 32 (17) ◽  
pp. 5659-5676 ◽  
Author(s):  
Biao Chen ◽  
Huiling Qin ◽  
Guixing Chen ◽  
Huijie Xue

Abstract The sea surface salinity (SSS) varies largely as a result of the evaporation–precipitation difference, indicating the source or sink of regional/global water vapor. This study identifies a relationship between the spring SSS in the tropical northwest Pacific (TNWP) and the summer rainfall of the East Asian monsoon region (EAMR) during 1980–2017. Analysis suggests that the SSS–rainfall link involves the coupled ocean–atmosphere–land processes with a multifacet evolution. In spring, evaporation and water vapor flux divergence were enhanced in some years over the TNWP where an anomalous atmospheric anticyclone was established and a high SSS was well observed. As a result, the convergence of water vapor flux and soil moisture over the EAMR was strengthened. This ocean-to-land water vapor transport pattern was sustained from spring to summer and played a leading role in the EAMR rainfall. Moreover, the change in local spring soil moisture helped to amplify the summer rainfall by modifying surface thermal conditions and precipitation systems over the EAMR. As the multifacet evolution is closely related to the large-scale ocean-to-land water vapor transport, it can be well represented by the spring SSS in the TNWP. A random forest regression algorithm was used to further evaluate the relative importance of spring SSS in predicting summer rainfall compared to other climate indices. As the SSS is now monitored routinely by satellite and the global Argo float array, it can serve as a good metric for measuring the water cycle and as a precursor for predicting the EAMR rainfall.


2013 ◽  
Vol 118 (4) ◽  
pp. 1585-1600 ◽  
Author(s):  
Suxiang Yao ◽  
Qian Huang ◽  
Yaocun Zhang ◽  
Xu Zhou

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Haiwen Liu ◽  
Jiarui Miao ◽  
Kaijun Wu ◽  
Mengxing Du ◽  
Yuxiang Zhu ◽  
...  

Previous studies indicate that the summer (July-August) rainfall over North China has decreased since the mid-1970s due to the weakening of East Asian summer monsoon (EASM). However, this study firstly discovers the new evidences that the summer rainfall over North China had a significant increasing tendency during 1979–1996; since 1997, this increasing tendency has halted while more summer droughts occurred over North China. One important cause for the halted increasing tendency over North China is the interdecadal decrease of the westerly water vapor transport during 1997–2016 in addition to the weakened EASM. The decrease of the westerly water vapor transport during 1997–2016 was due to the interdecadal warming over Lake Baikal. The interdecadal warming in the upper troposphere at 200 hPa forced the weakening of the upper-level zonal winds since 1997, which resulted in the anomalous descending flow over the north side of North China and the halted precipitation trend in North China.


2013 ◽  
Vol 9 (4) ◽  
pp. 4263-4291
Author(s):  
S. Nan ◽  
M. Tan ◽  
P. Zhao

Abstract. Further verification about the circulation effect of stalagmite δ18O in East Asian monsoon region needs the quantitative description for the proportion of water vapor transport (WVT) from different source regions. WVT passageway intensities are defined as regionally averaged WVT flux modes in this paper. The ratio between two WVT passageways' intensities represents relative intensity of the two WVT passageways. Using the NCEP-NCAR reanalysis data for 1948–2011, the ratios of the intensities of three WVT passageways from low latitudes (the intensity of WVT from Bay of Bengal (IBOB), the intensity of WVT from South China Sea (ISCS) and the intensity of WVT from western North Pacific (IWNP) in summer are calculated. SB is for the ISCS-IBOB ratio, WB for the IWNP-IBOB ratio, and WS for the IWNP-ISCS ratio. The decadal increase occurs in the time series of WB and WS, with higher values in 1976–1995 and lower values in 1950–1975, probably resulting from the strengthening of WVT from WNP in the midterm of 1970s. East Asian atmospheric circulations, WVTs and previous SST characters corresponding to the ratios are analyzed. The result indicates that SB, WB and WS may properly reflect the relative intensities between ISCS and IBOB, between IWNP and IBOB, and between IWNP and ISCS, respectively. For high SB years, the Asian Low and the western Pacific subtropical high (WPSH) weaken. The southwesterly winds from BOB to the Yangtze River valley by the southeast of the Tibetan Plateau weaken and the WVT from BOB to East Asia weakens. The southwesterly winds from SCS to East Asia strengthen and the WVT from SCS to East Asia strengthens. In high WB years, the Asian Low weakens and the WPSH shifts westwards, enhances and enlarges. The WVT from WNP to East Asia increases because of the strengthening of the easterly winds on the south of the WPSH. The westerly winds from BOB to East Asia by Indo-China Peninsula decrease and the WVT from BOB to East Asia weakens. The atmospheric circulation and WVT associated with WS are similar with those associated with WB. There are close relationships between WB (and WS) and the WPSH area, position and intensity. In high WB (and WS) years, the WPSH shifts westwards, enlarges and enhances. There is no obvious anomalous previous SST signal in tropical Indian Ocean and equatorial central and eastern Pacific for anomalous SB years. WB and WS are closely related to previous SST signal. When the equatorial central and eastern Pacific is in El Niño phase, SST in the tropical Indian Ocean, BOB and SCS is high and SST at middle latitudes in North Pacific is low, WB and WS tend to be high. After the midterm of 1970s, the equatorial central and eastern Pacific is often in El Niño phase. It is in agreement with higher WB in 1976–1995 than that in 1950–1975. In light of circulation effect of stalagmite δ18O in East Asia, high WB implies high stalagmite δ18O. Therefore, the interdecadal increase of WB in 1976–1995 than in 1950–1975 provides the proof using the conception of circulation effect to explain the interdecadal change of stalagmite δ18O at most regions in East Asia.


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