scholarly journals Weakening anomalies of East Asian Summer Precipitation Influenced by the Tibetan Plateau Warming Amplification

2019 ◽  
Author(s):  
Mei Liang ◽  
Jianjun Xu ◽  
Liguang Wu ◽  
Xiangde Xu
Keyword(s):  
Tibetan Plateau ◽  
Temperature Change ◽  
East Asian ◽  
Summer Precipitation ◽  
Warming Trend ◽  
Northwestern Pacific ◽  
The Tibetan Plateau ◽  
Southeastern Part ◽  
Northern Asia ◽  
Surrounding Areas

Abstract. The present study documents the on East Asian precipitation in summer influenced by elevation-dependent temperature change over the Tibetan Plateau (TP). The temperature of the TP and its surrounding areas decreases with altitude by 0.43–0.45 °C/100 meters, which is lower than the 0.6 °C/−100 meters in the troposphere. The magnitude of the trend of temperature increase with elevation and the amplification of warming over the TP comprise an important feature of the temperature change. TP warming is consistently the important contributor to the variation of East Asian precipitation in summer from 1979 to 2016, but their relationship weakens as the warming over the TP amplifies. The southern flood–northern drought pattern is weak compared with when the TP warming trend has been removed. Warming amplification of the TP may weaken the atmospheric circulation anomaly pattern. The rate of anticyclonic circulation strengthening has slowed in the upper and lower levels over Mongolia in East Asia, which leads to the northern drought feature weaken. Meanwhile striking cyclonic circulation anomalies are reduced in the southeastern part of China, the northern part of the South China Sea, and the northwestern Pacific. The atmospheric response to TP warming might be related to two distinct Rossby wave trains. After TP warming amplifying, one in the extratropics that moves along the upper-level westerly jetstream and the other in the tropics that moves along the low-level monsoon westerly have weakened. The downdrafts prevailed in the Northern Asia receded, which is conducive to precipitation in the area. Updrafts prevailed in the Southeast Asia is deteriorating, which is not advantageous to precipitation.

scholarly journals IMPACT OF TIBETAN PLATEAU SNOW COVER ON ABRUPT INTERDECADAL PRECIPITATION CHANGE OVER THE INDOCHINA PENINSULA IN THE MID-1990S

2019 ◽  
Vol XLII-3/W9 ◽  
pp. 57-62
Author(s):  
Y. Ha ◽  
Y. M. Zhu ◽  
Y. J. Hu ◽  
Z. Zhong
Keyword(s):  
Tibetan Plateau ◽  
Snow Cover ◽  
Summer Precipitation ◽  
Tropical Indian Ocean ◽  
Western Pacific Subtropical High ◽  
Precipitation Change ◽  
Interdecadal Change ◽  
Northwestern Pacific ◽  
The Tibetan Plateau ◽  
Indochina Peninsula

Abstract. Abrupt interdecadal changes in summer precipitation (May – September) over the Indochina Peninsula in the past 40 years have been investigated based on the NCEP-NCAR reanalysis product over 1979–2013 and multiple precipitation datasets. The mechanism for the abrupt change is explored. Results indicate that an abrupt interdecadal change in summer precipitation over the Indochina Peninsula occurred in the middle 1990s, and the annual mean summer precipitation during 1994–2002 increased by about 10% compared to that during 1982–1993. The most significant precipitation change occurred in the central and northern peninsula. Further analysis reveals that the interdecadal decrease in snow cover over the Tibetan Plateau in the winter and spring contributed to the summer precipitation increase over the Indochina Peninsula. The decrease in snow cover over the Tibetan Plateau actually increased the thermal contrast between the Tibetan Plateau and the tropical Indian Ocean-northwestern Pacific, leading to intensified summer monsoon over the northwestern Pacific and the South China Sea. As a result, westerly anomalies occurred from the Bay of Bengal to the northwestern Pacific, while anomalous cyclonic circulation prevailed in the upper levels above East Asia. Correspondingly, the western Pacific subtropical high weakened and shifted eastward. Under the joint effects of the above circulation patterns, the atmosphere became wetter in the Indochina Peninsula and summer precipitation increased. Results of the present study provide a theoretical basis for the prediction of long-term summer precipitation change in the Indochina Peninsula.

scholarly journals Decreasing Influence of Summer Snow Cover Over the Western Tibetan Plateau on East Asian Precipitation Under Global Warming

2021 ◽  
Vol 9 ◽  
Author(s):  
Zhibiao Wang ◽  
Renguang Wu ◽  
Zhang Chen ◽  
Lihua Zhu ◽  
Kai Yang ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Snow Cover ◽  
East Asian ◽  
Summer Precipitation ◽  
Northern China ◽  
The Tibetan Plateau ◽  
Western Tibetan Plateau ◽  
Asian Summer ◽  
Tibetan Plateau Snow Cover ◽  
East Asian Summer Precipitation

In recent years, some studies emphasized the influence of western Tibetan Plateau summer snow on the East Asian summer precipitation. With the temperature rise in the past decades, the snow cover over the western Tibetan Plateau in summer has significantly decreased. This raises the question whether the impact of the Tibetan Plateau snow has changed. The present study identifies a prominent change in the influence of the western Tibetan Plateau snow cover on the East Asian summer precipitation. Before the early 2000’s, positive precipitation anomalies extend from the southeastern Tibetan Plateau through the Yangtze River to Japan and Korea and negative anomalies cover southeast China corresponding to more Tibetan Plateau snow cover. After the early 2000’s, with the reduction of snow cover variability, below-normal and above-normal summer precipitation occurs over northern China-Mongolia and northeast Asia, respectively, corresponding to more Tibetan Plateau snow cover. The change in the influence of the Tibetan Plateau snow on the East Asian summer precipitation is associated with an obvious change in the atmospheric circulation anomaly pattern. Before the early 2000’s, the wind anomalies display a south-north contrast pattern with anomalous convergence along the Yangtze River. After the early 2000’s, an anomalous cyclone occupies Northeast China with anomalous southerlies and northerlies over northeast Asia and northern China, respectively. The Tibetan Plateau snow cover variation after the early 2000’s is associated with the northeast Indian summer precipitation. The model experiments confirm that the weakened influence of summer western Tibetan Plateau snow cover on the East Asian atmospheric circulation and precipitation with the reduced snow cover anomalies.

scholarly journals Atmospheric Thermal and Dynamic Vertical Structures of Summer Hourly Precipitation in Jiulong of the Tibetan Plateau

Atmosphere ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 505
Author(s):  
Yonglan Tang ◽  
Guirong Xu ◽  
Rong Wan ◽  
Xiaofang Wang ◽  
Junchao Wang ◽  
...  
Keyword(s):  
Wind Speed ◽  
Tibetan Plateau ◽  
Precipitation Amount ◽  
Summer Precipitation ◽  
The Tibetan Plateau ◽  
Hourly Precipitation ◽  
Air Convection ◽  
Precipitation Variation ◽  
Long Term Observation

It is an important to study atmospheric thermal and dynamic vertical structures over the Tibetan Plateau (TP) and their impact on precipitation by using long-term observation at representative stations. This study exhibits the observational facts of summer precipitation variation on subdiurnal scale and its atmospheric thermal and dynamic vertical structures over the TP with hourly precipitation and intensive soundings in Jiulong during 2013–2020. It is found that precipitation amount and frequency are low in the daytime and high in the nighttime, and hourly precipitation greater than 1 mm mostly occurs at nighttime. Weak precipitation during the daytime may be caused by air advection, and strong precipitation at nighttime may be closely related with air convection. Both humidity and wind speed profiles show obvious fluctuation when precipitation occurs, and the greater the precipitation intensity, the larger the fluctuation. Moreover, the fluctuation of wind speed is small in the morning, large at noon and largest at night, presenting a similar diurnal cycle to that of convective activity over the TP, which is conductive to nighttime precipitation. Additionally, the inverse layer is accompanied by the inverse humidity layer, and wind speed presents multi-peaks distribution in its vertical structure. Both of these are closely related with the underlying surface and topography of Jiulong. More studies on physical mechanism and numerical simulation are necessary for better understanding the atmospheric phenomenon over the TP.

scholarly journals Impact of Land Use Change on the Local Climate over the Tibetan Plateau

2010 ◽  
Vol 2010 ◽  
pp. 1-6 ◽  
Author(s):  
Jiming Jin ◽  
Shihua Lu ◽  
Suosuo Li ◽  
Norman L. Miller
Keyword(s):  
Land Use ◽  
Tibetan Plateau ◽  
Land Use Change ◽  
Lower Surface ◽  
Warming Trend ◽  
The Tibetan Plateau ◽  
Area Index ◽  
Local Climate ◽  
Significant Downward Trend ◽  
Three Rivers

Observational data show that the remotely sensed leaf area index (LAI) has a significant downward trend over the east Tibetan Plateau (TP), while a warming trend is found in the same area. Further analysis indicates that this warming trend mainly results from the nighttime warming. The Single-Column Atmosphere Model (SCAM) version 3.1 developed by the National Center for Atmospheric Research is used to investigate the role of land use change in the TP local climate system and isolate the contribution of land use change to the warming. Two sets of SCAM simulations were performed at the Xinghai station that is located near the center of the TP Sanjiang (three rivers) Nature Reserve where the downward LAI trend is largest. These simulations were forced with the high and low LAIs. The modeling results indicate that, when the LAI changes from high to low, the daytime temperature has a slight decrease, while the nighttime temperature increases significantly, which is consistent with the observations. The modeling results further show that the lower surface roughness length plays a significant role in affecting the nighttime temperature increase.

Dynamics of evapotranspiration and variations in different land-cover regions over the Tibetan Plateau during 1961-2014

2021 ◽  
Author(s):  
Shan Lin ◽  
Genxu Wang ◽  
Zhaoyong Hu ◽  
Kewei Huang ◽  
Xiangyang Sun ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Land Cover ◽  
Northwestern Part ◽  
The Tibetan Plateau ◽  
Southeastern Part ◽  
Available Energy ◽  
Forest Region ◽  
Energy Factors ◽  
Term Change ◽  
Increasing Trend

AbstractIn this study, the spatiotemporal changes and driving factors of evapotranspiration (ET) over the Tibetan Plateau (TP) are assessed from 1961-2014, based on a revised generalized nonlinear complementary (nonlinear-CR) model. The average annual ET on the TP was 328 mm/year. The highest ET value (711 mm/year) was found in the forest region in the southeastern part of the TP, and the lowest value (151 mm/year) was found in the desert region in the northwestern part of the TP. In terms of the contribution of different sub-regions to the total amount of ET for the whole plateau, the meadow and steppe regions contributed the most to the total amount of ET of TP, accounting for 30% and 18.5%, respectively. The interannual ET presented a significant increasing trend with a value of 0.26 mm/year from 1961 to 2014, and a significant positive ET trend was found over 35% of the region, mainly in the southeastern part of the plateau. The increasing trend of ET in swamp areas was the largest, while that in the desert areas was the smallest. In terms of the seasonality, the ET over the plateau and different land-cover regions increased the most in summer, followed by spring, while the change in ET in winter was not obvious. The energy factors dominated the long-term change in the annual ET over the plateau. In addition, the available energy is the controlling factor for ET changes in humid areas such as forests and shrublands. Energy and water factors together dominate the ET changes in arid areas.

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