A modeling study of the effects of anomalous snow cover over the Tibetan Plateau upon the South Asian summer monsoon

2004 ◽  
Vol 21 (6) ◽  
pp. 964-975 ◽  
Author(s):  
Liu Huaqiang ◽  
Sun Zhaobo ◽  
Wang Ju ◽  
Min Jinzhong
Keyword(s):  
Tibetan Plateau ◽  
Snow Cover ◽  
South Asian ◽  
Summer Monsoon ◽  
Asian Summer Monsoon ◽  
The Tibetan Plateau ◽  
South Asian Summer Monsoon ◽  
The South ◽  
Asian Summer ◽  
Modeling Study

scholarly journals Reexamining the barrier effect of Tibetan Plateau on the South Asian summer monsoon

2013 ◽  
Vol 9 (4) ◽  
pp. 5019-5036
Author(s):  
G.-S. Chen ◽  
Z. Liu ◽  
J. E. Kutzbach
Keyword(s):  
Tibetan Plateau ◽  
South Asian ◽  
Summer Monsoon ◽  
Asian Monsoon ◽  
Asian Summer Monsoon ◽  
Monsoon Circulation ◽  
The Tibetan Plateau ◽  
South Asian Summer Monsoon ◽  
The South ◽  
Monsoon System

Abstract. The Tibetan Plateau has been conventionally treated as an elevated heat source driving the Asian monsoon system, especially for the South Asian monsoon. Numerous model simulations with general circulation models (GCMs) support this hypothesis with the finding that the Asian monsoon system is weak or absent with all elevated topographies removed. A recent model simulation shows that the South Asian summer monsoon circulation is little affected with only the Himalayas (no Tibetan Plateau) kept as a barrier, leading to a hypothesis of the barrier "blocking" mechanism of the Tibetan Plateau. In this paper, a new series of experiments are designed to reexamine this barrier effect. We find that with the barrier, the large-scale summer monsoon circulation over South Asia is simulated in general agreement with the full Tibetan Plateau, which is consistent with the previous finding. However there remains significant differences in both wind field and precipitation field elsewhere, suggesting a role of the full Tibetan Plateau as well. Moreover, the proposed barrier "blocking" mechanism is not found in our experiments. The energy of the low-level air and the convection is lower/weaker over the Indian subcontinent in the full Tibetan Plateau experiment than that in the no-Tibetan Plateau experiment or the barrier only experiment, which is opposite to the barrier "blocking" hypothesis. Instead, there is a similar candle-like latent heating in the middle troposphere along the south edge of the Tibetan Plateau in both the full Tibetan Plateau and the barrier experiments, whereas this "candle heating" disappears in the no-Tibetan Plateau experiment. We propose that this candle heating is the key to understand the mechanisms of the Tibetan Plateau on the South Asian monsoon. Future studies are needed to check the source of the "candle heating" and its effect on the Asian monsoon.

scholarly journals Reexamining the barrier effect of the Tibetan Plateau on the South Asian summer monsoon

2014 ◽  
Vol 10 (3) ◽  
pp. 1269-1275 ◽  
Author(s):  
G.-S. Chen ◽  
Z. Liu ◽  
J. E. Kutzbach
Keyword(s):  
Tibetan Plateau ◽  
South Asian ◽  
Summer Monsoon ◽  
Asian Monsoon ◽  
Asian Summer Monsoon ◽  
Monsoon Circulation ◽  
The Tibetan Plateau ◽  
South Asian Summer Monsoon ◽  
The South ◽  
Monsoon System

Abstract. The Tibetan Plateau has been conventionally treated as an elevated heat source driving the Asian monsoon system, especially for the South Asian monsoon. Numerous model simulations with general circulation models (GCMs) support this hypothesis with the finding that the Asian monsoon system is weak or absent when all elevated topography is removed. A recent model simulation shows that the South Asian summer monsoon circulation is little affected with only the Himalayas (no-Tibetan Plateau) kept as a barrier, leading to a hypothesis of the barrier "blocking" mechanism of the Tibetan Plateau. In this paper, a new series of experiments are designed to reexamine this barrier effect. We find that with the barrier, the large-scale summer monsoon circulation over South Asia is simulated in general agreement with the full Tibetan Plateau, which is consistent with the previous finding. However, there remains significant differences in both wind and precipitation fields, suggesting a role for the full Tibetan Plateau as well. Moreover, the proposed barrier blocking mechanism is not found in our experiments. The energy of the low-level air and the convection are lower and weaker over the Indian subcontinent in the full Tibetan Plateau experiment than that in the no-Tibetan Plateau experiment or the barrier only experiment, which is in contrast to the barrier blocking hypothesis. Instead, there is a similar candle-like latent heating in the middle troposphere along the southern edge of the Tibetan Plateau in both the full Tibetan Plateau and the barrier experiments, whereas this "candle heating" disappears in the no-Tibetan Plateau experiment. We propose that this candle heating is the key to understanding the mechanisms of the Tibetan Plateau on the South Asian monsoon. Future studies are needed to check the source of the "candle heating" and its effect on the Asian monsoon.

scholarly journals Trapping, chemistry and export of trace gases in the South Asian summer monsoon observed during CARIBIC flights in 2008

2015 ◽  
Vol 15 (5) ◽  
pp. 6967-7018 ◽  
Author(s):  
A. Rauthe-Schöch ◽  
A. K. Baker ◽  
T. J. Schuck ◽  
C. A. M. Brenninkmeijer ◽  
A. Zahn ◽  
...  
Keyword(s):  
South Asian ◽  
Summer Monsoon ◽  
Asian Summer Monsoon ◽  
Trace Gases ◽  
Particle Dispersion ◽  
Atmospheric Pollutants ◽  
South Asian Summer Monsoon ◽  
The South ◽  
Air Masses ◽  
Asian Summer

Abstract. The CARIBIC (Civil Aircraft for the Regular Investigation of the Atmosphere Based on an Instrument Container) passenger aircraft observatory performed in situ measurements at 10–12 km altitude in the South Asian summer monsoon anticyclone between June and September 2008. These measurements enable us to investigate this atmospheric region, which so far has mostly been observed from satellites, using the broad suite of trace gases and aerosols measured by CARIBIC. Elevated levels of a range of atmospheric pollutants were recorded e.g. carbon monoxide, total reactive nitrogen oxides, aerosol particles and several volatile organic compounds. The measurements provide detailed information about the chemical composition of air in different parts of the monsoon anticyclone, particularly of ozone precursors. While covering a range of 3500 km inside the monsoon anticyclone, CARIBIC observations show remarkable consistency, i.e. with regular latitudinal patterns of trace gases during the entire monsoon period. Trajectory calculations indicate that these air masses originated mainly from South Asia and Mainland Southeast Asia. Using the CARIBIC trace gas and aerosol measurements in combination with the Lagrangian particle dispersion model FLEXPART we investigated the characteristics of monsoon outflow and the chemical evolution of air masses during transport. Estimated photochemical ages of the air were found to agree well with transport times from a source region east of 95° E. The photochemical ages of the air in the southern part of the monsoon anticyclone were consistently younger (less than 7 days) and the air masses mostly in an ozone forming chemical regime. In its northern part the air masses were older (up to 13 days) and had unclear ozone formation or destruction potential. Based on analysis of forward trajectories several receptor regions were identified. In addition to predominantly westward transport, we found evidence for efficient transport (within 10 days) to the Pacific and North America, particularly during June and September, and also of cross-tropopause exchange, which was strongest during June and July. Westward transport to Africa and further to the Mediterranean was the main pathway during July.

A Moist Entropy Budget View of the South Asian Summer Monsoon Onset

2019 ◽  
Vol 46 (8) ◽  
pp. 4476-4484
Author(s):  
Ding Ma ◽  
Adam H. Sobel ◽  
Zhiming Kuang ◽  
Martin S. Singh ◽  
Ji Nie
Keyword(s):  
South Asian ◽  
Summer Monsoon ◽  
Asian Summer Monsoon ◽  
Monsoon Onset ◽  
South Asian Summer Monsoon ◽  
The South ◽  
Summer Monsoon Onset ◽  
Asian Summer ◽  
Entropy Budget
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