Potential Changes in Extreme Events Under Global Climate Change

2008 ◽  
Vol 3 (1) ◽  
pp. 39-50 ◽  
Author(s):  
Koji Dairaku ◽  
◽  
Seita Emori ◽  
Hironori Higashi ◽  
Keyword(s):  
Climate Change ◽  
Global Warming ◽  
Summer Monsoon ◽  
Extreme Events ◽  
Extreme Precipitation ◽  
General Circulation ◽  
Asian Summer Monsoon ◽  
Climate Conditions ◽  
Asian Summer ◽  
A1b Scenario

Climate-related disasters are a serious problem in Asia. Advances in the understanding of meteorology and in the development of monitoring and forecasting systems have enhanced early warning systems, contributing immensely to reducing fatalities resulting from typhoons, cyclones, and floods. The frequency of extreme events causing water-related disasters has increased, however, over the last decade and may grow in the future due to anthropogenic activity. The sections that follow introduce two recent efforts in hydrologic projection in Asia. Time-slice ensemble experiments using a high-resolution (T106) atmospheric general circulation model (AGCM) on the earth simulator revealed changes in the South Asian summer monsoon resulting from climate change. Model results under global warming conditions suggest increases in mean and extreme precipitation during the Asian summer monsoon. increases generally attributed to greater atmospheric moisture content. a thermodynamic change. Dynamic changes limit the intensification of mean precipitation. Enhanced extreme precipitation over land in South Asia arises from dynamic rather than thermodynamic changes. The impact of global warming on heavy precipitation features and flood risks in the Tama River basin in Japan is addressed using 12 atmosphere-ocean coupled general circulation models (AOGCMs). Multi-model ensemble average 200-year quantiles in Tokyo from 2050 to 2300 under Intergovernmental Panel on Climate Changes (IPCC) Special Reports on Emissions Scenarios (SRES) A1B scenario climate conditions were 1.07-1.20 times greater than that under present climate conditions. A 200-year quantile extreme event in the present occurs in much shorter return periods in the A1B scenario. High-water discharge in the basin rose by 10%-26% and flood volume increased by 46%-131% for precipitation in a 200-year return period. The risk of flooding in the basin is thus, even though the increase of extreme precipitation is not substantial, projected to be much higher than that presently estimated.

Global Warming Projection by an Atmospheric Global Model with 20-km Grid

2008 ◽  
Vol 3 (1) ◽  
pp. 4-14 ◽  
Author(s):  
Shoji Kusunoki ◽  
◽  
Jun Yoshimura ◽  
Hiromasa Yoshimura ◽  
Ryo Mizuta ◽  
...  
Keyword(s):  
Global Warming ◽  
Summer Monsoon ◽  
East Asian Summer Monsoon ◽  
General Circulation ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Circulation Model ◽  
Global Climate Models ◽  
Rain Band ◽  
Asian Summer

We projected global warming on the Earth Simulator using a very high horizontal resolution atmospheric global general circulation model with 20-km grids, targeting tropical cyclones (TCs) and the rain band (Baiu) during the East Asian summer monsoon season because these bring typical extreme events and global climate models have not yielded reliable simulations or projections due to insufficient resolutions. Our model reproduces TCs and a Baiu rain band reasonably well under present-day climate conditions. In a warmer climate at the end of this century, the model projects, under A1B scenario of the Intergovernmental Panel on Climate Change (IPCC) Special Report on Emission Scenarios (SRES), that the annual mean formation frequency of TCs decreases by about 30% globally but increased in the North Atlantic and TCs with largemaximumsurface winds increase. The Baiu rain band activity tends to intensify and last longer until August, suggesting more damages due to heavy rainfalls in a warmer climate. This is a review paper mainly originated from published articles on tropical cyclone by Oouchi et al. (2006) [26] and on the East Asian summer monsoon by Kusunoki et al. (2006) [17].

scholarly journals Searching for a fingerprint of global warming in the Asian summer monsoon

MAUSAM ◽  
2021 ◽  
Vol 52 (1) ◽  
pp. 213-220
Author(s):  
DAVID B. STEPHENSON ◽  
HERVE DOUVILLE ◽  
K. RUPA KUMAR
Keyword(s):  
Global Warming ◽  
Summer Monsoon ◽  
General Circulation ◽  
Large Scale ◽  
Climate Models ◽  
Asian Summer Monsoon ◽  
Quantitative Agreement ◽  
Monsoon Circulation ◽  
Clear Trend ◽  
Asian Summer

This study investigates possible trends in several large scale indices that describe the Asian summer monsoon. Results from recent atmospheric general circulation experiments are used to provide clues as to how the monsoon might be changing due to the effects of global warming. Interestingly, this study has found that the large-scale wind shear monsoon indices have been decreasing at a rate of 0.1-0.3% per year (based on NCEP/CAR reanalysis 1958-98) in quantitative agreement with recent results from doubled CO2 simulations made using several state-of-the-art climate models. Nevertheless, despite the weakening of the monsoon circulation, all-India rainfall shows no clear trend in either the model results or in the observation reanalysis from 1958-98. Multiple regression is used to separate out the "dynamical" contribution from the observed all-India rainfall index, and a clear increasing trend then emerges in the "non-dynamical" residual. A simple dimensionless Multivariate Monsoon Index (MMI) is proposed that could be of use in monitoring global warming changes in the monsoon.

scholarly journals The Variability of the Indian–East Asian Summer Monsoon Interface in Relation to the Spring Seesaw Mode between the Indian Ocean and the Central-Western Pacific

2016 ◽  
Vol 29 (13) ◽  
pp. 5027-5040 ◽  
Author(s):  
Jie Cao ◽  
Shu Gui ◽  
Qin Su ◽  
Yali Yang
Keyword(s):  
Indian Ocean ◽  
Summer Monsoon ◽  
East Asian Summer Monsoon ◽  
General Circulation ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Western Pacific ◽  
Observational Analysis ◽  
Westerly Winds ◽  
Asian Summer

Abstract The interannual zonal movement of the interface between the Indian summer monsoon and the East Asian summer monsoon (IIE), associated with the spring sea surface temperature (SST) seesaw mode (SSTSM) over the tropical Indian Ocean (TIO) and the tropical central-western Pacific (TCWP), is studied for the period 1979–2008. The observational analysis is based on Twentieth Century Reanalysis data (version 2) of atmospheric circulations, Extended Reconstructed SST data (version 3), and the Climate Prediction Center Merged Analysis of Precipitation. The results indicate that the IIE’s zonal movement is significantly and persistently correlated with the TIO–TCWP SSTSM, from spring to summer. The results of two case studies resemble those obtained by regression analysis. Experiments using an atmospheric general circulation model (ECHAM6) substantiate the key physical processes revealed in the observational analysis. When warmer (colder) SSTs appear in the TIO and colder (warmer) SSTs occur in the TCWP, the positive (negative) SSTSM forces anomalous easterly (westerly) winds over the Bay of Bengal (BOB), South China Sea (SCS), and western North Pacific (WNP). The anomalous easterly (westerly) winds further result in a weakened (strengthened) southwest summer monsoon over the BOB and a strengthened (weakened) southeast summer monsoon over the SCS and WNP. This causes the IIE to shift farther eastward (westward) than normal.

Sensitivity of East Asian summer monsoon precipitation to the location of the Tibetan Plateau

2021 ◽  
pp. 1-36
Author(s):  
Soo-Hyun Seok ◽  
Kyong-Hwan Seo
Keyword(s):  
Tibetan Plateau ◽  
Summer Monsoon ◽  
East Asian Summer Monsoon ◽  
General Circulation ◽  
Asian Summer Monsoon ◽  
East Asian ◽  
Circulation Model ◽  
Dynamical Response ◽  
The Tibetan Plateau ◽  
Asian Summer

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.

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