Characteristics of the seasonal variation of the surface total heating over the Tibetan Plateau and its surrounding area in summer 1998 and its relationship with the convection over the subtropical area of the western Pacific

2003 ◽  
Vol 20 (3) ◽  
pp. 343-348 ◽  
Author(s):  
Wei Li ◽  
Longxun Chen
Keyword(s):  
Seasonal Variation ◽  
Tibetan Plateau ◽  
Western Pacific ◽  
The Tibetan Plateau ◽  
Surrounding Area ◽  
Subtropical Area ◽  
The Western Pacific

Dominant Interannual and Decadal Variability of Winter Surface Air Temperature over Asia and the Surrounding Oceans

2008 ◽  
Vol 21 (6) ◽  
pp. 1371-1386 ◽  
Author(s):  
Chihiro Miyazaki ◽  
Tetsuzo Yasunari
Keyword(s):  
Tibetan Plateau ◽  
Air Temperature ◽  
Surface Air Temperature ◽  
Silk Road ◽  
Western Pacific ◽  
The Tibetan Plateau ◽  
The Third ◽  
The North ◽  
Atmospheric Wave ◽  
Fourth Mode

Abstract To clarify the interannual variability of winter surface air temperature (SAT) over Asia and the surrounding oceans, the authors applied principal component analysis to normalized monthly SATs. The first mode represents the Asian north–south dipole pattern with a node over the Tibetan Plateau. This component has close relationships to the Arctic Oscillation and cold surge variability around Southeast Asia, showing decadal oscillation with signal changes in 1988 and 1997. The second mode is the inner-Asian mode with a center to the north of the Tibetan Plateau. This component connects to fluctuations of not only the western Siberian high but also the Icelandic low, which is associated with the pattern of the polar vortex over Eurasia. A recent warming trend and possible relationship to solar activity are also shown. The modes of Asian SAT variability associated with ENSO are extracted as the north–south dipole mode over the tropical western Pacific and Japan (the third mode) and Silk Road mode (the fourth mode). The two independent modes appear to be caused by different sea surface temperature (SST) anomalies over the western Pacific and Indian Ocean and their associated atmospheric Rossby wave responses: the atmospheric wave trains over both the north and south of the Tibetan Plateau in the third mode, and the atmospheric wave train that propagates toward the Silk Road via Greenland in the fourth mode.

scholarly journals Origin and radiative forcing of black carbon transported to the Himalayas and Tibetan Plateau

2010 ◽  
Vol 10 (9) ◽  
pp. 21615-21651 ◽  
Author(s):  
M. Kopacz ◽  
D. L. Mauzerall ◽  
J. Wang ◽  
E. M. Leibensperger ◽  
D. K. Henze ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Tibetan Plateau ◽  
Black Carbon ◽  
Radiative Forcing ◽  
Middle Eastern ◽  
Central China ◽  
The Tibetan Plateau ◽  
Adjoint Sensitivity ◽  
Snow Albedo ◽  
Northern Tibetan Plateau

Abstract. The remote and high elevation regions of central Asia are influenced by black carbon (BC) emissions from a variety of locations. BC deposition contributes to melting of glaciers and questions exist, of both scientific and policy interest, as to the origin of the BC reaching the glaciers. We use the adjoint of the GEOS-Chem model to identify the location from which BC arriving at a variety of locations in the Himalayas and Tibetan Plateau originates. We then calculate its direct and snow-albedo radiative forcing. We analyze the seasonal variation in the origin of BC using an adjoint sensitivity analysis, which provides a detailed map of the location of emissions that directly contribute to black carbon concentrations at receptor locations. We find that emissions from northern India and central China contribute the majority of BC to the Himalayas, although the precise location varies with season. The Tibetan Plateau receives most BC from western and central China, as well as from India, Nepal, the Middle East, Pakistan and other countries. The magnitude of contribution from each region varies with season and receptor location. We find that sources as varied as African biomass burning and Middle Eastern fossil fuel combustion can significantly contribute to the BC reaching the Himalayas and Tibetan Plateau. We compute radiative forcing in the snow-covered regions and estimate the forcing due to the BC induced snow-albedo effect at about 5–15 W m−2 within the region, an order of magnitude larger than radiative forcing due to the direct effect, and with significant seasonal variation in the northern Tibetan Plateau. Radiative forcing from reduced snow albedo accelerates glacier melting. Our analysis can help inform mitigation efforts to slow the rate of glacial melt by identifying regions that make the largest contributions to BC deposition in the Himalayas and Tibetan Plateau.

The Dynamics of Quasi-Stationary Atmospheric Rivers and Their Implications for Monsoon Onset

2021 ◽  
Author(s):  
Hung-I Lee ◽  
Jonathan L. Mitchell
Keyword(s):  
General Circulation ◽  
Phase Speed ◽  
Circulation Model ◽  
Monsoon Onset ◽  
Western Pacific ◽  
Eastern Pacific ◽  
The Tibetan Plateau ◽  
Atmospheric Rivers ◽  
Upper Level ◽  
The Western Pacific

AbstractA global Hovmöller diagram of column water vapor (CWV) at 30°N from daily ERA-Interim reanalysis data shows seasonally migrating North Pacific/Atlantic quasi-stationary atmospheric rivers (QSARs) located in the Eastern Pacific/Atlantic in winter and propagate to the Western Pacific/Atlantic in summer. Simplified general circulation model (GCM) experiments produce QSAR-like features if the boundary conditions include (1) the sea surface temperature contrast from the tropical warm pool-cold tongue and (2) topographic contrast similar to the Tibetan plateau. Simulated QSARs form downstream of topographic contrast during winter and coincide with it in summer. Two models of baroclinic instability demonstrate that QSARs coincide with the location where the most unstable mode phase speed equals that of the upper-level zonal winds. A consistent interpretation is that the waves become quasi-stationary at this location and break. The location of quasistationarity migrates from the Eastern Pacific/Atlantic in the winter, when upper-level winds are strong and extended over the basin, to the Western Pacific/Atlantic when winds are weak and contracted. Low-level wind convergence and moist static energy coincide with QSARs, and since the former two are essential ingredients to monsoon formation, this implies an important role for QSARs in monsoon onset. This connection opens a new window into the dynamics of subtropical monsoon extensions.

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