scholarly journals Numerical study of surface energy partitioning on the Tibetan Plateau: comparative analysis of two biosphere models

2009 ◽  
Vol 6 (6) ◽  
pp. 10849-10881
Author(s):  
J. Hong ◽  
J. Kim

Abstract. The Tibetan Plateau is a critical region in the research of biosphere-atmosphere interactions on both regional and global scales due to its relation to Asian summer monsoon and El Niño. The unique environment on the Plateau provides valuable information for the evaluation of the models' surface energy partitioning associated with the summer monsoon. In this study, we investigated the surface energy partitioning on this important area through comparative analysis of two biosphere models constrained by the in-situ observation data. Indeed, the characteristics of the Plateau provide a unique opportunity to clarify the structural deficiencies of biosphere models as well as new insight into the surface energy partitioning on the Plateau. Our analysis showed that the observed inconsistency between the two biosphere models was mainly related to: 1) the parameterization for soil evaporation; 2) the way to deal with roughness lengths of momentum and scalars; and 3) the parameterization of subgrid velocity scale for aerodynamic conductance. Our study demonstrates that one should carefully interpret the modeling results on the Plateau especially during the pre-monsoon period.

2010 ◽  
Vol 7 (2) ◽  
pp. 557-568 ◽  
Author(s):  
J. Hong ◽  
J. Kim

Abstract. The Tibetan Plateau is a critical region in the research of biosphere-atmosphere interactions on both regional and global scales due to its relation to Asian summer monsoon and El Niño. The unique environment on the Plateau provides valuable information for the evaluation of the models' surface energy partitioning associated with the summer monsoon. In this study, we investigated the surface energy partitioning on this important area through comparative analysis of two biosphere models constrained by the in-situ observation data. Indeed, the characteristics of the Plateau provide a unique opportunity to clarify the structural deficiencies of biosphere models as well as new insight into the surface energy partitioning on the Plateau. Our analysis showed that the observed inconsistency between the two biosphere models was mainly related to: 1) the parameterization for soil evaporation; 2) the way to deal with roughness lengths of momentum and scalars; and 3) the parameterization of subgrid velocity scale for aerodynamic conductance. Our study demonstrates that one should carefully interpret the modeling results on the Plateau especially during the pre-monsoon period.


2003 ◽  
Vol 28 (1-3) ◽  
pp. 63-74 ◽  
Author(s):  
Yaoming Ma ◽  
Zhongbo Su ◽  
Toshio Koike ◽  
Tandong Yao ◽  
Hirohiko Ishikawa ◽  
...  

2020 ◽  
Vol 7 (3) ◽  
pp. 516-533 ◽  
Author(s):  
Jianchun Bian ◽  
Dan Li ◽  
Zhixuan Bai ◽  
Qian Li ◽  
Daren Lyu ◽  
...  

Abstract Due to its surrounding strong and deep Asian summer monsoon (ASM) circulation and active surface pollutant emissions, surface pollutants are transported to the stratosphere from the Tibetan Plateau region, which may have critical impacts on global climate through chemical, microphysical and radiative processes. This article reviews major recent advances in research regarding troposphere–stratosphere transport from the region of the Tibetan Plateau. Since the discovery of the total ozone valley over the Tibetan Plateau in summer from satellite observations in the early 1990s, new satellite-borne instruments have become operational and have provided significant new information on atmospheric composition. In addition, in situ measurements and model simulations are used to investigate deep convection and the ASM anticyclone, surface sources and pathways, atmospheric chemical transformations and the impact on global climate. Also challenges are discussed for further understanding critical questions on microphysics and microchemistry in clouds during the pathway to the global stratosphere over the Tibetan Plateau.


2020 ◽  
Vol 202 ◽  
pp. 103114 ◽  
Author(s):  
Jin-Feng Li ◽  
Gan Xie ◽  
Jian Yang ◽  
David K. Ferguson ◽  
Xiao-Dong Liu ◽  
...  

2020 ◽  
Vol 11 (9) ◽  
pp. 1543-1551
Author(s):  
Jinqiang Zhang ◽  
Xiangao Xia ◽  
Hongrong Shi ◽  
Xuemei Zong ◽  
Jun Li

2021 ◽  
pp. 1-36
Author(s):  
Soo-Hyun Seok ◽  
Kyong-Hwan Seo

AbstractRecent studies have highlighted that a primary mechanism of the East Asian summer monsoon (EASM) is the fluid dynamical response to the Tibetan Plateau (TP), that is, orographically forced Rossby waves. With this mechanism in mind, this study explores how changes in the location of the TP affect the EASM precipitation. Specifically, the TP is moved in the four cardinal directions using idealized general circulation model experiments. The results show that the monsoon aspects are entirely determined by the location of the TP. Interestingly, the strongest EASM precipitation occurs when the TP is situated near its current location, a situation in which downstream southerlies are well developed from the surface to aloft. However, southerlies into the EASM region weaken as the TP moves, which in turn reduces the precipitation. Nevertheless, as long as it moves in the east–west direction, the TP is likely to force the stationary waves that induce precipitation over the mid-latitudes (not necessarily over East Asia). In contrast, moving the TP well north of its original location does not induce strong monsoon flows over the EASM region, resulting in the driest case. Meanwhile, although the southward movement of the TP triggers downstream southerlies to some extent, it does not lead to an increase in the precipitation. Overall, these results show that the location of the TP is crucial in determining the EASM precipitation, and the latter is much more sensitive to the displacement of the TP in the meridional direction than in the zonal direction.


2019 ◽  
Author(s):  
Jianzhong Ma ◽  
Christoph Brühl ◽  
Qianshan He ◽  
Benedikt Steil ◽  
Vlassis A. Karydis ◽  
...  

Abstract. Enhanced aerosol abundance in the upper troposphere and lower stratosphere (UTLS) associated with the Asian summer monsoon (ASM), is referred to as the Asian Tropopause Aerosol Layer (ATAL). The chemical composition, microphysical properties and climate effects of aerosols in the ATAL have been the subject of discussion over the past decade. In this work, we use the ECHAM/MESSy Atmospheric Chemistry (EMAC) general circulation model at a relatively fine grid resolution (about 1.1 × 1.1 degrees) to numerically simulate the emissions and chemistry of aerosols and their precursors in the UTLS within the ASM anticyclone during the years 2010–2012. We find a pronounced maximum in aerosol extinction in the UTLS over the Tibetan Plateau, which to a large extent is caused by mineral dust emitted from the northern Tibetan Plateau and slope areas, lofted to an altitude of at least 10 km, and accumulating within the anticyclonic circulation. Our simulations show that mineral dust, water soluble compounds, such as nitrate and sulfate, and associated liquid water dominate aerosol extinction in the UTLS within the ASM anticyclone. Due to shielding of high background sulfate concentrations outside the anticyclone from volcanoes, a relative minimum of aerosol extinction within the anticyclone in the lower stratosphere is simulated, being most pronounced in 2011 when the Nabro eruption occurred. In contrast to mineral dust and nitrate concentrations, sulfate increases with increasing altitude due to the larger volcano effects in the lower stratosphere compared to the upper troposphere. Our study indicates that the UTLS over the Tibetan Plateau can act as a well-defined conduit for natural and anthropogenic gases and aerosols into the stratosphere.


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