scholarly journals Controlling factors of historical variation of winter Tibetan Plateau snow cover revealed by large‐ensemble experiments

2021 ◽  
Author(s):  
Shixue Li ◽  
Tomonori Sato ◽  
Tetsu Nakamura ◽  
Xiaoyue Liu ◽  
Wenkai Guo
Keyword(s):  
Tibetan Plateau ◽  
Snow Cover ◽  
Controlling Factors ◽  
Large Ensemble ◽  
Historical Variation ◽  
Tibetan Plateau Snow Cover ◽  
Ensemble Experiments

Historical change of winter Tibetan Plateau snow cover and its controlling factors

2021 ◽  
Author(s):  
Shixue Li ◽  
Tomonori Sato ◽  
Tetsu Nakamura
Keyword(s):  
Global Warming ◽  
Tibetan Plateau ◽  
Snow Cover ◽  
Internal Variability ◽  
Controlling Factors ◽  
Historical Change ◽  
The Tibetan Plateau ◽  
Vapor Flux ◽  
The Impact ◽  
Tibetan Plateau Snow Cover

<p>This study investigates the controlling factors of the interannual variability of Tibetan Plateau snow cover (TPSC) in winter. Since snow observation in Tibetan Plateau is limited in space and time, high-resolution multi-satellite data for TPSC were analyzed during 1982-2016. In addition, a large ensemble AGCM experiment from d4PDF (hereafter, HIST), driven by observed SST and anthropogenic forcings were analyzed during 1951-2010 to compare the contributions arising from internal variability and external forcings including the change in greenhouse gases (GHGs) concentration on TPSC variation. In this study TPSC fraction (hereafter, TPSCF) is defined as the percentage of the snow-covered area over the Tibetan Plateau. For both observation and HIST, high and low TPSCF years determined by the standardized January-March TPSCF were analyzed. The range of interannual TPSCF variation (i.e., TPSCF difference between high and low TPSCF years) is about 11% in both observation and the model, suggesting the AGCM well reproduced the TPSCF variability in the interannual timescale. </p><p>We found that high TPSCF is linked to a positive-AO-like pattern. The interannual variation of the observed AO index and TPSCF are significantly correlated. In d4PDF high TPSCF more likely appears with a higher (positive) AO index and vice versa. In high TPSCF years, the subtropical jet is strengthened, which significantly enhances zonal water vapor flux reaching the plateau supporting more precipitation. Another interesting result is a disagreement for ENSO’s contribution to TPSC appears between observation and HIST. However, several members in HIST show a feature close to the observation, in which TPSCF anomalies are not sensitive to the El Niño/La Niña events. Thus, this weak linkage between ENSO and TPSCF is more likely due to the limited cases of observations rather than the model bias. Finally, by comparing HIST and non-warming experiments (NAT), we found historical global warming has decreased the snow-to-rain ratio over TP. Nonetheless, increased precipitation compensates for it. As a result, the impact of historical global warming on TPSCF could be considered negligibly weak.</p>

Rapid response of the East Asian trough to Tibetan Plateau snow cover

2020 ◽  
Vol 41 (1) ◽  
pp. 251-261 ◽  
Author(s):  
Wenkai Li ◽  
Bo Qiu ◽  
Weidong Guo ◽  
Pang‐chi Hsu
Keyword(s):  
Tibetan Plateau ◽  
Snow Cover ◽  
East Asian ◽  
Rapid Response ◽  
East Asian Trough ◽  
Tibetan Plateau Snow Cover

IOD influence on the early winter tibetan plateau snow cover: diagnostic analyses and an AGCM simulation

2011 ◽  
Vol 39 (7-8) ◽  
pp. 1643-1660 ◽  
Author(s):  
Chaoxia Yuan ◽  
Tomoki Tozuka ◽  
Toshio Yamagata
Keyword(s):  
Tibetan Plateau ◽  
Snow Cover ◽  
Early Winter ◽  
Tibetan Plateau Snow Cover

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.

Influence of Eastern Tibetan Plateau Spring Snow Cover on North American Air Temperature and Its Interdecadal Change

2020 ◽  
Vol 33 (12) ◽  
pp. 5123-5139
Author(s):  
Zhibiao Wang ◽  
Renguang Wu ◽  
Anmin Duan ◽  
Xia Qu
Keyword(s):  
North America ◽  
Tibetan Plateau ◽  
Snow Cover ◽  
Atmospheric Circulation ◽  
Air Temperature ◽  
North American ◽  
Eastern Tibetan Plateau ◽  
The North ◽  
The Relationship ◽  
Tibetan Plateau Snow Cover

AbstractPrevious studies revealed the influence of the autumn–winter Tibetan Plateau snow cover on atmospheric circulation and climate in the North American region. The present study documents the relationship between the eastern Tibetan Plateau snow cover and the North American air temperature in spring and the associated physical processes using satellite-based snow cover, reanalysis atmospheric and surface variables, observation-based surface air temperature (SAT), and sea surface temperature (SST). A stable relationship is identified between the eastern Tibetan Plateau snow cover and the North American SAT in spring before the mid-2000s. Positive snow-cover anomalies over the eastern Tibetan Plateau induce cooling in the local atmospheric column. The atmospheric cooling stimulates a large-scale atmospheric wave pattern at the upper level that extends northeastward from the eastern Tibetan Plateau via northeast Asia and the North Pacific to North America. An anomalous high forms over North America, accompanied by anomalous descent. In the northwestern part, the horizontal advection by anomalous southerly winds along the west flank of anomalous anticyclone induces SAT increase. In the central part, the enhanced surface sensible heat flux following anomalous descent-induced downward shortwave radiation increase leads to SAT increase. The relationship between the eastern Tibetan Plateau snow cover and the North American SAT is weakened after the mid-2000s. The weakened relationship is attributed to an intensified impact of tropical central Pacific SST anomalies on the North American SAT variations through a Pacific–North America-like atmospheric circulation pattern, which overcomes the influence of the Tibetan Plateau snow-cover anomalies.

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