scholarly journals South Asian monsoon climate change and radiocarbon in the Arabian Sea during early and middle Holocene

2002 ◽  
Vol 17 (4) ◽  
pp. 15-1-15-12 ◽  
Author(s):  
Michael Staubwasser ◽  
Frank Sirocko ◽  
Pieter M. Grootes ◽  
Helmut Erlenkeuser
Keyword(s):  
Climate Change ◽  
South Asian ◽  
Arabian Sea ◽  
Asian Monsoon ◽  
South Asian Monsoon ◽  
Monsoon Climate ◽  
Middle Holocene ◽  
Early And Middle Holocene

Characteristics of Precipitating Convective Systems in the South Asian Monsoon

2011 ◽  
Vol 12 (1) ◽  
pp. 3-26 ◽  
Author(s):  
Ulrike Romatschke ◽  
Robert A. Houze
Keyword(s):  
South Asian ◽  
Diurnal Cycle ◽  
Bay Of Bengal ◽  
Arabian Sea ◽  
Asian Monsoon ◽  
South Asian Monsoon ◽  
Western Himalayas ◽  
The South ◽  
Convective Systems ◽  
Large Systems

Abstract Eight years of Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR) data show how convective systems of different types contribute to precipitation of the South Asian monsoon. The main factor determining the amount of precipitation coming from a specific system is its horizontal size. Convective intensity and/or number of embedded convective cells further enhance its precipitation production. The precipitation of the monsoon is concentrated in three mountainous regions: the Himalayas and coastal ranges of western India and Myanmar. Along the western Himalayas, precipitation falls mainly from small, but highly convective systems. Farther east along the foothills, systems are more stratiform. These small and medium systems form during the day, as the monsoon flow is forced upslope. Nighttime cooling leads to downslope flow and triggers medium-sized systems at lower elevations. At the mountainous western coasts of India and Myanmar, small and medium systems are present throughout the day, as an orographic response to the southwesterly flow, with a slight superimposed diurnal cycle. Medium systems are favored over the eastern parts of the Arabian Sea and large systems are favored over the Bay of Bengal when an enhanced midlevel cyclonic circulation occurs over the northern parts of these regions. The systems forming upstream of coastal mountains over the Bay of Bengal are larger than those over the Arabian Sea, probably because of the moister conditions over the bay. The large systems over the bay exhibit a pronounced diurnal cycle, with systems forming near midnight and maximizing in midday.

Phased evolution and variation of the South Asian monsoon, and resulting weathering and surface erosion in the Himalaya–Karakoram Mountains, since late Pliocene time using data from Arabian Sea core

2020 ◽  
Vol 157 (6) ◽  
pp. 864-878 ◽  
Author(s):  
Huayu Lu ◽  
Ruixuan Liu ◽  
Linhai Cheng ◽  
Han Feng ◽  
Hanzhi Zhang ◽  
...  
Keyword(s):  
South Asian ◽  
Arabian Sea ◽  
Asian Monsoon ◽  
Monsoon Rainfall ◽  
South Asian Monsoon ◽  
Monsoon Precipitation ◽  
Late Pliocene ◽  
Weathering Intensity ◽  
Karakoram Mountains ◽  
The Himalaya

AbstractWe investigate the phased evolution and variation of the South Asian monsoon and resulting weathering intensity and physical erosion in the Himalaya–Karakoram Mountains since late Pliocene time (c. 3.4 Ma) using a comprehensive approach. Neodymium and strontium isotopic compositions and single-grain zircon U–Pb age spectra reveal the sources of the deposits in the east Arabian Sea, and show a combination of sources from the Himalaya and the Karakoram–Kohistan–Ladakh Mountains, with sediments from the Indian Peninsula such as the Deccan Traps or Craton. We interpret shifts in the sediment sources to have been forced by sea-level changes that correlate with South Asian monsoon rainfall variation since late Pliocene time. We collected 908 samples from the International Ocean Discovery Program Hole U1456A, which was drilled in the east Arabian Sea. Time series of hematite content and grain size of the sediments were examined downcore. We found South Asian monsoon precipitation and weathering intensity experienced three phases from late Pliocene time. Lower monsoon precipitation, with a lower variability and strong weathering intensity, occurred during 3.4–2.4 Ma; an increased and more variable South Asian monsoon rainfall, along with strengthened but fluctuating weathering intensity, occurred at 1.8–1.1 Ma; and a reduced rainfall with lower South Asian monsoon precipitation variability and moderate weathering intensity marked the period 1.1–0.1 Ma. Maximum entropy spectral analysis and wavelet transform show that there were orbital-dominated cycles of periods c. 100 and c. 41 ka in these proxy-based time series. We propose that the monsoon, sea level, global temperature and insolation together forced the weathering and erosion in SW Asia.

scholarly journals Understanding land surface response to changing South Asian monsoon in a warming climate

2015 ◽  
Vol 6 (2) ◽  
pp. 569-582 ◽  
Author(s):  
M. V. S Ramarao ◽  
R. Krishnan ◽  
J. Sanjay ◽  
T. P. Sabin
Keyword(s):  
Climate Change ◽  
South Asian ◽  
Land Surface ◽  
Asian Monsoon ◽  
Global Climate ◽  
Monsoon Circulation ◽  
South Asian Monsoon ◽  
Monsoon Precipitation ◽  
Surface Response ◽  
Regional Land

Abstract. Recent studies have drawn attention to a significant weakening trend of the South Asian monsoon circulation and an associated decrease in regional rainfall during the last few decades. While surface temperatures over the region have steadily risen during this period, most of the CMIP (Coupled Model Intercomparison Project) global climate models have difficulties in capturing the observed decrease of monsoon precipitation, thus limiting our understanding of the regional land surface response to monsoonal changes. This problem is investigated by performing two long-term simulation experiments, with and without anthropogenic forcing, using a variable resolution global climate model having high-resolution zooming over the South Asian region. The present results indicate that anthropogenic effects have considerably influenced the recent weakening of the monsoon circulation and decline of precipitation. It is seen that the simulated increase of surface temperature over the Indian region during the post-1950s is accompanied by a significant decrease of monsoon precipitation and soil moisture. Our analysis further reveals that the land surface response to decrease of soil moisture is associated with significant reduction in evapotranspiration over the Indian land region. A future projection, based on the representative concentration pathway 4.5 (RCP4.5) scenario of the Intergovernmental Panel on Climate Change (IPCC), using the same high-resolution model indicates the possibility for detecting the summer-time soil drying signal over the Indian region during the 21st century in response to climate change. Given that these monsoon hydrological changes have profound socio-economic implications the present findings provide deeper insights and enhance our understanding of the regional land surface response to the changing South Asian monsoon. While this study is based on a single model realization, it is highly desirable to have multiple realizations to establish the robustness of the results.

scholarly journals Interannual Variability and Seasonality of Precipitation in the Indus River Basin

2019 ◽  
Vol 20 (3) ◽  
pp. 379-395 ◽  
Author(s):  
Samar Minallah ◽  
Valeriy Y. Ivanov
Keyword(s):  
Climate Change ◽  
River Basin ◽  
South Asian ◽  
Management Practices ◽  
Asian Monsoon ◽  
Southern Oscillation ◽  
South Asian Monsoon ◽  
Indus River ◽  
The South ◽  
Indus River Basin

Abstract The Indus River basin is highly vulnerable to water scarcity due to increasing population, unsustainable management practices, and climate change. Yet the regional hydroclimate and precipitation dynamics remain poorly understood. Using running trend and spectral analysis with multiple gauge-based, remote sensing, and reanalysis precipitation datasets, this study analyzes precipitation temporal variability, its subregional variations, and the main seasonal drivers, particularly the South Asian monsoon. The results uncover remarkable alternation of long-term positive and negative interdecadal precipitation trends in the basin over the past half century. These trends have led to substantial changes in water input over the region at the time scales comparable to climate assessment periods (30 years), and therefore this high intrinsic variability must be accounted for in climate change adaptation studies. This study also reconstructs onset and withdrawal dates of the South Asian monsoon that exhibit interdecadal variability, but their dominant modes differ from that of annual precipitation. The findings hypothesize that higher-frequency variability in El Niño–Southern Oscillation is likely to have a pronounced impact on monsoon onset and duration in the studied region.

Late Cretaceous–Paleogene Indian monsoon climate vis-à-vis movement of the Indian plate, and the birth of the South Asian Monsoon

2021 ◽  
Vol 93 ◽  
pp. 89-100
Author(s):  
Harshita Bhatia ◽  
Mahasin Ali Khan ◽  
Gaurav Srivastava ◽  
Taposhi Hazra ◽  
R.A. Spicer ◽  
...  
Keyword(s):  
South Asian ◽  
Late Cretaceous ◽  
Asian Monsoon ◽  
Indian Monsoon ◽  
Indian Plate ◽  
South Asian Monsoon ◽  
Monsoon Climate ◽  
The South

scholarly journals Synoptic Preconditions for Extreme Flooding during the Summer Asian Monsoon in the Mumbai Area

2014 ◽  
Vol 15 (1) ◽  
pp. 229-242 ◽  
Author(s):  
Marco Lomazzi ◽  
Dara Entekhabi ◽  
Joaquim G. Pinto ◽  
Giorgio Roth ◽  
Roberto Rudari
Keyword(s):  
Time Series ◽  
South Asian ◽  
Asian Monsoon ◽  
Indian Subcontinent ◽  
Monsoon Season ◽  
Value Added ◽  
South Asian Monsoon ◽  
Flood Events ◽  
The South ◽  
Synoptic Conditions

Abstract The summer monsoon season is an important hydrometeorological feature of the Indian subcontinent and it has significant socioeconomic impacts. This study is aimed at understanding the processes associated with the occurrence of catastrophic flood events. The study has two novel features that add to the existing body of knowledge about the South Asian monsoon: 1) it combines traditional hydrometeorological observations (rain gauge measurements) with unconventional data (media and state historical records of reported flooding) to produce value-added century-long time series of potential flood events and 2) it identifies the larger regional synoptic conditions leading to days with flood potential in the time series. The promise of mining unconventional data to extend hydrometeorological records is demonstrated in this study. The synoptic evolution of flooding events in the western-central coast of India and the densely populated Mumbai area are shown to correspond to active monsoon periods with embedded low pressure centers and have far-upstream influences from the western edge of the Indian Ocean basin. The coastal processes along the Arabian Peninsula where the currents interact with the continental shelf are found to be key features of extremes during the South Asian monsoon.

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