Reconstruction of Indian monsoon precipitation variability between 4.0 and 1.6 ka BP using speleothem δ18O records from the Central Lesser Himalaya, India

2017 ◽  
Vol 10 (16) ◽  
Author(s):  
Lalit M. Joshi ◽  
Bahadur Singh Kotlia ◽  
S. M. Ahmad ◽  
C.-C. Wu ◽  
Jaishri Sanwal ◽  
...  
Keyword(s):  
Indian Monsoon ◽  
Precipitation Variability ◽  
Lesser Himalaya ◽  
Monsoon Precipitation

Investigating the factors affecting Monsoon precipitation under climate change

2020 ◽  
Author(s):  
Harry Mutton ◽  
Mat Collins ◽  
Hugo Lambert ◽  
Rob Chadwick
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Indian Monsoon ◽  
Physiological Effect ◽  
Sea Surface ◽  
Monsoon Circulation ◽  
Radiative Effect ◽  
Monsoon Precipitation ◽  
Surface Temperature Change ◽  
The Impact

<p>The Monsoons produce some of the largest levels of uncertainty in projected precipitation change across the globe, and addressing this uncertainty is a key issue that must be faced in order to allow correct adaptation policy to be put in place.</p><p> </p><p>A set of CMIP6 GCM experiments, that allow the full effect of CO<sub>2</sub> forcing to be decomposed into individual components, highlight the leading factors that produce changes in monsoon precipitation. The results reveal a high spatial variability in these factors, with changes in the Indian Monsoon dominated by the effect of sea surface temperatures and the direct radiative effect of increased CO<sub>2</sub>, and changes in the South American Monsoon governed by the plant physiological effect and the direct radiative effect of increased CO<sub>2</sub>. The processes behind these precipitation changes are also investigated by looking at variations in atmospheric circulation and surface temperature. Results of the patterned sea surface temperature experiment demonstrate a slow-down of the Indian Monsoon circulation possibly driven by an anomalously warm Indian Ocean.</p><p> </p><p>This analysis has been performed for all land monsoon regions, decomposing the full CO<sub>2</sub> forcing into; uniform and patterned sea surface temperature change, the plant physiological effect, the direct radiative effect and the impact of sea-ice melt. These results can help identify emergent constraints, as well as indicate which aspects of climate models need to be improved in order to reduce model uncertainty.</p>

scholarly journals East Asian summer monsoon precipitation variability since the last deglaciation

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Fahu Chen ◽  
Qinghai Xu ◽  
Jianhui Chen ◽  
H. John B. Birks ◽  
Jianbao Liu ◽  
...  
Keyword(s):  
Summer Monsoon ◽  
East Asian Summer Monsoon ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Precipitation Variability ◽  
Last Deglaciation ◽  
Monsoon Precipitation ◽  
Asian Summer ◽  
The Last Deglaciation

Thermodynamic Bias in the Multimodel Mean Boreal Summer Monsoon*

2013 ◽  
Vol 26 (7) ◽  
pp. 2279-2287 ◽  
Author(s):  
William R. Boos ◽  
John V. Hurley
Keyword(s):  
Tibetan Plateau ◽  
Climate Model ◽  
Indian Monsoon ◽  
Boreal Summer ◽  
The Tibetan Plateau ◽  
Tropospheric Temperature ◽  
Moist Convection ◽  
Monsoon Precipitation ◽  
Thermodynamic State ◽  
Western Asia

Abstract Here it is shown that almost all models participating in the Coupled Model Intercomparison Project (CMIP) exhibit a common bias in the thermodynamic structure of boreal summer monsoons. The strongest bias lies over South Asia, where the upper-tropospheric temperature maximum is too weak, is shifted southeast of its observed location, and does not extend as far west over Africa as it does in observations. Simulated Asian maxima of surface air moist static energy are also too weak and are located over coastal oceans rather than in their observed continental position. The spatial structure of this bias suggests that it is caused by an overly smoothed representation of topography west of the Tibetan Plateau, which allows dry air from the deserts of western Asia to penetrate the monsoon thermal maximum, suppressing moist convection and cooling the upper troposphere. In a climate model with a decent representation of the thermodynamic state of the Asian monsoon, the qualitative characteristics of this bias can be recreated by truncating topography just west of the Tibetan Plateau. This relatively minor topographic modification also produces a negative anomaly of Indian precipitation of similar sign and amplitude to the CMIP continental Indian monsoon precipitation bias. Furthermore, in simulations of next-century climate warming, this topographic modification reduces the amplitude of the increase in Indian monsoon precipitation. These results confirm the importance of topography west of the Tibetan Plateau for South Asian climate and illustrate the need for careful assessments of the thermodynamic state of model monsoons.

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