Spatio-Temporal Variations of Water Vapor Budget over the Tibetan Plateau in Summer and Its Relationship with the Indo-Pacific Warm Pool

Atmosphere

Yanyan Li¹  Qing Dong¹  Zi Yin¹  Deli Meng¹  Fanping Kong¹  Jingyi Liu¹ 

[1] Key Laboratory of Digital Earth Science, The Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100094, China;

关键词: water vapor budget;    Tibetan Plateau;    sea surface temperature;    Indo-Pacific warm pool;    surface latent heat flux;   

DOI  :  10.3390/atmos11080828

来源: DOAJ

【 摘 要 】

The water vapor budget (WVB) over the Tibetan Plateau (TP) is closely related to the large-scale atmospheric moisture transportation of the surrounding mainland and oceans, especially for the Indo-Pacific warm pool (IPWP). However, the procession linkage between the WVBs over the TP and its inner basins and IPWP has not been sufficiently elucidated. In this study, the relationship between the summer WVB over the TP and the IPWP was quantitatively investigated using reanalysis datasets and satellite-observed sea surface temperature (SST). The results show that: (1) the mean total summer vapor budget (WVB_t) over the TP in the period of 1979–2018 was 72.5 × 10⁶ kg s⁻¹. Additionally, for the 13 basins within the TP, the summer WVB has decreased from southeast to northwest; the Yarlung Zangbo River Basin had the highest WVB (33.7%), followed by the Upper Yangtze River Basin, Ganges River Basin and Qiangtang Plateau. (2) For the past several decades, the WVB_t over the TP has experienced an increasing trend (3.81 × 10⁶ kg s⁻¹ decade⁻¹), although the southern boundary budget (WVB_s) contributed the most and is most closely related with the WVB_t, while the eastern boundary budget (WVB_e) experienced a decreasing trend (4.21 × 10⁶ kg s⁻¹ decade⁻¹) which was almost equal to the interdecadal variations of the WVB_t. (3) For the IPWP, we defined a new warm pool index of surface latent heat flux (WPI-slhf), and found that an increasing WPI-slhf would cause an anticyclone anomaly in the equatorial western Indian Ocean (near 70° E), resulting in the increased advent of water vapor to the TP. (4) On the interdecadal scale, the correlation coefficients of the variation of the summer WVB_t over the TP with the WPI-slhf and Indian Ocean Dipole (IOD) signal were 0.86 and 0.85, respectively (significant at the 0.05% level). Therefore, the warming and the increasing slhf of the IPWP would significantly contribute to the increasing WVB of the TP in recent decades.

【 授权许可】

Unknown