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

Atmosphere ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 828
Author(s):  
Deli Meng ◽  
Qing Dong ◽  
Fanping Kong ◽  
Zi Yin ◽  
Yanyan Li ◽  
...  
Keyword(s):  
Water Vapor ◽  
Indian Ocean ◽  
Tibetan Plateau ◽  
River Basin ◽  
Large Scale ◽  
Warm Pool ◽  
The Tibetan Plateau ◽  
Southern Boundary ◽  
Pacific Warm Pool ◽  
Water Vapor Budget

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 (WVBt) 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 WVBt over the TP has experienced an increasing trend (3.81 × 106 kg s−1 decade−1), although the southern boundary budget (WVBs) contributed the most and is most closely related with the WVBt, while the eastern boundary budget (WVBe) experienced a decreasing trend (4.21 × 106 kg s−1 decade−1) which was almost equal to the interdecadal variations of the WVBt. (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 WVBt 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.

scholarly journals Climatology and physical mechanisms of the tropospheric warm cores over the Tibetan Plateau and its vicinity

2021 ◽  
Author(s):  
Ke Shang ◽  
Xiaodong Liu ◽  
Buwen Dong
Keyword(s):  
Tibetan Plateau ◽  
Active Region ◽  
Large Scale ◽  
Asian Summer Monsoon ◽  
Warm Pool ◽  
Formation Mechanisms ◽  
The Tibetan Plateau ◽  
Temperature Deviation ◽  
Physical Mechanisms ◽  
Pacific Warm Pool

AbstractThe frequently observed tropospheric warm cores over the Tibetan Plateau (TP) are unique climate phenomena and are crucial to the Asian summer monsoon development. However, their climatological structure and formation mechanisms remain elusive and inconsistent among previous studies. In this work, two vertically separated warm cores, the upper-level warm cores (ULWCs) and lower-level warm cores (LLWCs), are identified based on the zonal temperature deviation. The LLWCs are basically confined below 450 hPa, and the ULWCs are mostly observed at 200–400 hPa. The active region of the LLWCs is generally within the TP domain and characterized by regional patches with high frequency occurrences. In contrast, the active region of the ULWCs is featured by a zonally elongated band along the southern TP. The physical mechanisms for the formations of these two distinct types of warm cores are revealed: the LLWCs are mainly generated and maintained by the surface diabatic heating, while the ULWCs are dominated by the large-scale circulation associated with the convection over the Indo-Pacific warm pool. During March–June, the ULWCs within the TP domain occur most frequently and the intensities attain their maxima. In March–April, the ULWCs are mainly determined by the TP adiabatic subsidence induced by the convection over the Indo-Pacific warm pool. In May–June, the warm advection induced by westerlies generates the downstream ULWCs and enhances the ULWCs formed in previous months. Hence it might be inappropriate in traditional view to attribute the tropospheric warm cores around the TP solely to the direct thermal effect of the elevated topography.

scholarly journals The Variability of Summer Atmospheric Water Cycle over the Tibetan Plateau and Its Response to the Indo-Pacific Warm Pool

2021 ◽  
Vol 13 (22) ◽  
pp. 4676
Author(s):  
Deli Meng ◽  
Wanjiao Song ◽  
Qing Dong ◽  
Zi Yin ◽  
Wenbo Zhao
Keyword(s):  
Water Vapor ◽  
Tibetan Plateau ◽  
Water Cycle ◽  
Warm Pool ◽  
Vapor Transport ◽  
Water Vapor Transport ◽  
The Tibetan Plateau ◽  
Atmospheric Water ◽  
Maritime Continent ◽  
Pacific Warm Pool

The Tibetan Plateau (TP), atmosphere, and Indo-Pacific warm pool (IPWP) together constitute a regional land–atmosphere–ocean water vapor transport system. This study uses remote sensing data, reanalysis data, and observational data to explore the spatiotemporal variations of the summer atmospheric water cycle over the TP and its possible response to the air-sea interaction in the IPWP during the period 1958–2019. The results reveal that the atmospheric water cycle process over the TP presented an interannual and interdecadal strengthening trend. The climatic precipitation recycle ratio (PRR) over the TP was 18%, and the stronger the evapotranspiration, the higher the PRR. On the interdecadal scale, the change in evapotranspiration has a significant negative correlation with the Pacific Decadal Oscillation (PDO) index. The variability of the water vapor transport (WVT) over the TP was controlled by the dynamic and thermal conditions inside the plateau and the external air-sea interaction processes of the IPWP. When the summer monsoon over the TP was strong, there was an anomalous cyclonic WVT, which increased the water vapor budget (WVB) over the TP. The central and eastern tropical Pacific, the maritime continent and the western Indian Ocean together constituted the triple Sea Surface Temperature (SST) anomaly, which enhanced the convective activity over the IPWP and induced a significant easterly wind anomaly in the middle and lower troposphere, and then generated pronounced easterly WVT anomalies from the tropical Pacific to the maritime continent and the Bay of Bengal. Affected by the air-sea changes in the IPWP, the combined effects of the upstream strengthening and the downstream weakening in the water vapor transport process, directly and indirectly, increased the water vapor transport and budget of TP.

scholarly journals Atmospheric Water Vapor Budget and its Long-term Trend over the Tibetan Plateau

2020 ◽  
Author(s):  
Hongru Yan ◽  
Jianping Huang ◽  
Yongli He ◽  
Yuzhi Liu ◽  
Tianhe Wang ◽  
...  
Keyword(s):  
Water Vapor ◽  
Tibetan Plateau ◽  
Atmospheric Water Vapor ◽  
The Tibetan Plateau ◽  
Atmospheric Water ◽  
Term Trend ◽  
Long Term Trend ◽  
Water Vapor Budget

scholarly journals Interannual Variation of Summer Atmospheric Heat Source over the Tibetan Plateau and the Role of Convection around the Western Maritime Continent

2015 ◽  
Vol 29 (1) ◽  
pp. 121-138 ◽  
Author(s):  
Xingwen Jiang ◽  
Yueqing Li ◽  
Song Yang ◽  
Kun Yang ◽  
Junwen Chen
Keyword(s):  
Water Vapor ◽  
Tibetan Plateau ◽  
Heat Source ◽  
Interannual Variation ◽  
The Tibetan Plateau ◽  
The South ◽  
Maritime Continent ◽  
Southern Boundary ◽  
Atmospheric Heat Source ◽  
Atmospheric Heat

Abstract The impacts of summer atmospheric heat source over the Tibetan Plateau (TP) on regional climate variation have attracted extensive attention. However, few studies have focused on possible causes of the interannual variation of atmospheric heat source over the TP. Total heat (TH) is generally composed of three components: surface sensible heat, latent heat release of condensation (LH), and radiative convergence. In this study, it is found that interannual variation of summer TH is dominated by LH in the central and eastern TP. The atmospheric circulation patterns associated with the TH over the TP in June are different from those in July and August. Large TH is accompanied by a cyclone centered over the South China Sea in June, which is replaced by an anticyclone in July and August. The interannual variation of July–August TH over the central and eastern TP is significantly affected by convection around the western Maritime Continent (WMC) that modulates the LH over the southeastern TP. Enhanced WMC convection induces an anticyclone to the south of the TP, which favors water vapor transport to the southeastern TP and thus an increase in precipitation. Enhanced convection over the southeastern TP may exert a positive feedback on local precipitation through pumping more water vapor from the southern boundary. Both observations and model simulations indicate that the enhanced WMC convection can induce the anticyclone to the south of the TP and convection–circulation is important for maintenance of the anticyclone.

The different mechanisms of extreme snowfall in the eastern and southern Tibetan Plateau.

2021 ◽  
Author(s):  
Nan Yao ◽  
Lian Liu ◽  
Yaoming Ma
Keyword(s):  
Water Vapor ◽  
Tibetan Plateau ◽  
Large Scale ◽  
Snow Water Equivalent ◽  
Wrf Model ◽  
Eastern Region ◽  
The Tibetan Plateau ◽  
Local Circulation ◽  
China Meteorological Administration ◽  
Dynamic Conditions

<p>Snowfall is a key component of the hydrological system of the Tibetan Plateau (TP), and it is also a very sensitive factor to climate change. To understand the mechanism of extreme snowfall in different regions of the TP, we used the 50-year snow depth data from the China Meteorological Administration (CMA) ground observations and the ERA5 reanalysis datasets of European Centre for Medium-Range Weather Forecasts (ECMWF). Results show the threshold of extreme snow in the southern TP is four times greater than that in the eastern region. Sixteen numerical experiments using the weather research and forecasting (WRF) model were conducted to quantify the contribution of water vapor and dynamic conditions to snowfall events. Here are the preliminary results: (1) For the snowfall event caused by local circulation in the eastern TP, the contribution of dynamic conditions is greater than that of moisture conditions. An increase of 10% in the wind field (water vapor) will enhance the snow water equivalent (SWE) by more than 25% (10%). (2) For large-scale circulation, q has a greater effect. But the overall increase in snowfall is smaller than the local circulation. (3) The severe snowfall frequently takes place in the southern TP, where water vapor channel and topographic uplift are significant factors to snowfall. we think the southern simulation will produce interesting results. Our results will provide scientific reference in improving the snowstorm forecasting and disaster prevention and mitigation.</p>

scholarly journals Quantitative Analysis of Water Vapor Transport during Mei-Yu Front Rainstorm Period over the Tibetan Plateau and Yangtze-Huai River Basin

2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Hao Yang ◽  
Guan-yu Xu ◽  
Xiaofang Wang ◽  
Chunguang Cui ◽  
Jingyu Wang ◽  
...  
Keyword(s):  
Water Vapor ◽  
Indian Ocean ◽  
Tibetan Plateau ◽  
Heavy Rainfall ◽  
Initial Position ◽  
Vapor Transport ◽  
Water Vapor Transport ◽  
The Tibetan Plateau ◽  
Huai River ◽  
The Indian Ocean

There are continuous precipitation systems moving eastward from the Tibetan Plateau to the middle and lower reaches of the Yangtze-Huai River during the Mei-yu period. We selected 20 typical Mei-yu front precipitation cases from 2010 to 2015 based on observational and reanalysis data and studied the characteristics of their environmental fields. We quantitatively analyzed the transport and sources of water vapor in the rainstorms using the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT_4.9) model. All 20 Mei-yu front precipitation cases occurred in a wide region from the Tibetan Plateau to the Yangtze-Huai River. The South Asian high and upper level jet stream both had strong intensities during the Mei-yu front rainstorm periods. Heavy rainfall mainly occurred in the divergence zone to the right of the high-level jet and in the convergence zone of the low-level jet, where strong vertical upward flows provided the dynamic conditions required for heavy rainfall. The water vapor mainly originated from the Indian Ocean, Bay of Bengal, and South China Sea. 52% of the air masses over the western Tibetan Plateau originated from Central Asia, which were rich in water vapor. The water vapor contribution at the initial position was only 41.5% due to the dry, cold air mass over Eurasia, but increased to 47.6% at the final position. Over the eastern Tibetan Plateau to the Sichuan Basin region, 40% of the air parcels came from the Indian Ocean, which was the main channel for water vapor transport. For the middle and lower reaches of the Yangtze River, 37% of the air parcels originated from the warm and humid Indian Ocean. The water vapor contribution at the initial position was 38.6%, but increased to 40.2% after long-distance transportation.

scholarly journals Atmospheric Water Vapor Budget and Its Long‐Term Trend Over the Tibetan Plateau

2020 ◽  
Vol 125 (23) ◽  
Author(s):  
Hongru Yan ◽  
Jianping Huang ◽  
Yongli He ◽  
Yuzhi Liu ◽  
Tianhe Wang ◽  
...  
Keyword(s):  
Water Vapor ◽  
Tibetan Plateau ◽  
Atmospheric Water Vapor ◽  
The Tibetan Plateau ◽  
Atmospheric Water ◽  
Term Trend ◽  
Long Term Trend ◽  
Water Vapor Budget

scholarly journals Diagnostic analysis of a regional heavy snowfall event over the Tibetan Plateau using NCEP reanalysis data and WRF

2021 ◽  
Author(s):  
Lian Liu ◽  
Yaoming Ma ◽  
Nan Yao ◽  
Weiqiang Ma
Keyword(s):  
Water Vapor ◽  
Tibetan Plateau ◽  
Large Scale ◽  
Stable Stratification ◽  
Reanalysis Data ◽  
The Tibetan Plateau ◽  
Diagnostic Analysis ◽  
Heavy Snowfall ◽  
Low Level ◽  
Snowfall Event

AbstractSnowstorms frequently occur in spring over the heterogeneous underlying surface of the Tibetan Plateau, causing both economic and societal damage. What the intensity of factors triggering snowstorms remains poorly understood. This study quantitatively diagnoses water vapor, the thermodynamic and dynamic conditions of a large-scale heavy snowfall event over the Tibetan Plateau using reanalysis data. Here we show, a cold vortex, the Southern Branch Trough and a meridional shear line are favorable synoptic systems. The snowfall is characterized by low-layer (− 8.3 × 10−7 g s−1 hPa−1 cm−2) and whole-layer (− 4.5 × 10−4 g s−1 cm−2) moisture convergence, low-level atmospheric convergence and high-level divergence (± 3 × 10−4 s−1), low-level positive vorticity (4.8 × 10−4 s−1) and strong vertical velocity (− 4 Pa s−1). Although the convectively-stable stratification acted to suppress snowfall, the abundant water vapor and strong orographic uplift of Himalayas and the downhill wind speed convergence overcome this to trigger the heavy snowfall event witnessed in March 2017. These diagnostic results are well consistent with those from WRF simulation. Our study acknowledges the importance of WRF in diagnostic analysis, deepens the understanding of evolution mechanisms and provides theoretical references for accurate forecasting of such events over the Tibetan Plateau. It would aid the development of effective strategies for sustainable livestock, and the mitigation and prevention of snow disasters in this region.

scholarly journals Increased Chances of Drought in Southeastern Periphery of the Tibetan Plateau Induced by Anthropogenic Warming

2017 ◽  
Vol 30 (16) ◽  
pp. 6543-6560 ◽  
Author(s):  
Shuangmei Ma ◽  
Tianjun Zhou ◽  
Oliver Angélil ◽  
Hideo Shiogama
Keyword(s):  
Climate Change ◽  
Tibetan Plateau ◽  
Climate Models ◽  
Hadley Circulation ◽  
Warm Pool ◽  
Severe Drought ◽  
The Tibetan Plateau ◽  
Ensemble Simulations ◽  
Pacific Warm Pool ◽  
Drought Conditions

The southeastern periphery of the Tibetan Plateau (SEPTP) was hit by an extraordinarily severe drought in the autumn of 2009. Overall, the SEPTP has been gripped by a sustained drought for six consecutive years. To better understand the physical causes of these types of severe and frequent droughts and thus to improve their prediction and enhance the ability to adapt, many research efforts have been devoted to the disastrous droughts in the SEPTP. Nonetheless, whether the likelihood and strength of the severe droughts in the SEPTP, such as that in the autumn of 2009, have been affected by anthropogenic climate change remains unknown. This study first identifies the atmospheric circulation regime responsible for the SEPTP droughts and then explores how human-induced climate change has affected the severe droughts in the SEPTP. It is found that the drought conditions in the SEPTP have been driven by the Indian–Pacific warm pool (IPWP) sea surface temperature (SST) through strengthening of the local Hadley circulation and anomalously cyclonic motion over the South China Sea. Ensemble simulations of climate models demonstrate a robust increase in the dry and warm meteorological conditions seen during the 2009 SEPTP autumn drought due to anthropogenic global warming. Given that warming is expected to continue into the future, these results suggest that it is likely that drought conditions will become more common in the SEPTP.

scholarly journals Observations of water vapor mixing ratio profile and flux in the Tibetan Plateau based on the lidar technique

2016 ◽  
Vol 9 (3) ◽  
pp. 1399-1413 ◽  
Author(s):  
Songhua Wu ◽  
Guangyao Dai ◽  
Xiaoquan Song ◽  
Bingyi Liu ◽  
Liping Liu
Keyword(s):  
Boundary Layer ◽  
Water Vapor ◽  
Tibetan Plateau ◽  
Large Scale ◽  
Lower Troposphere ◽  
Water Vapor Transport ◽  
The Tibetan Plateau ◽  
Mixing Ratio ◽  
Wind Lidar ◽  
Water Vapor Mixing Ratio

Abstract. As a part of the third Tibetan Plateau Experiment of Atmospheric Sciences (TIPEX III) in China, a Raman water vapor, cloud and aerosol lidar and a coherent wind lidar were operated in Naqu (31.48° N, 92.06° E) with a mean elevation of more than 4500 m a.m.s.l. in summer of 2014. During the field campaign, the water vapor mixing ratio profiles were obtained and validated by radiosonde observations. The mean water vapor mixing ratio in Naqu in July and August was about 9.4 g kg−1 and the values vary from 6.0 to 11.7 g kg−1 near the ground according to the lidar measurements, from which a diurnal variation of water vapor mixing ratio in the planetary boundary layer was also illustrated in this high-elevation area. Furthermore, using concurrent measurements of vertical wind speed profiles from the coherent wind lidar, we calculated the vertical flux of water vapor that indicates the water vapor transport through updraft and downdraft. The fluxes were for a case at night with large-scale non-turbulent upward transport of moisture. It is the first application, to our knowledge, to operate continuously atmospheric observations by utilizing multi-disciplinary lidars at the altitude higher than 4000 m, which is significant for research on the hydrologic cycle in the atmospheric boundary layer and lower troposphere in the Tibetan Plateau.

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