Future Changes in extreme precipitation over South Asia and its causes

2021 ◽  
Author(s):  
Mayank Suman ◽  
Rajib Maity
Keyword(s):  
Climate Change ◽  
Indian Ocean ◽  
South Asia ◽  
Indian Summer Monsoon ◽  
Extreme Precipitation ◽  
Indian Ocean Dipole ◽  
South India ◽  
Central India ◽  
Moisture Flux ◽  
North India

<p>Indian Summer Monsoon is vulnerable to climate change. Analysis of precipitation over India suggests more increase in extreme precipitation over south India as compared to north and central India during post-1970 (1971-2017) as compared to pre-1970 (1930-1970) (Suman and Maity, 2020). This contrast in the characteristics of extreme precipitation over south and north India is expected to continue as revealed by the analysis of precipitation from the Coordinated Regional Downscaling Experiment (CORDEX) simulations. Additionally, precipitation extreme are expected to shift southward over South Asia in the future (2006-2100 as compared to 1961-2005). For instance, the Arabian Sea, south India, Myanmar, Thailand, and Malaysia are expected to have the maximum increase (~18.5 mm/day for RCP8.5 scenario) in mean extreme precipitation (average precipitation for the days with more than 99<sup>th</sup> percentile of daily precipitation). However, north and central India and Tibetan Plateau show relatively less increase (~2.7 mm/day for RCP8.5 scenario). The increase in extreme precipitation over most part of South Asia can be attributed to stronger monsoon due to increase in air temperature over Tibetan Platue and Himalayas, stronger positive Indian Ocean Dipole events, and high precipitatible water over land areas in the future. However, while analysis of moisture flux and moisture convergence at 850mb, an intense eastward shift is noticed for moisture flux (over Indian Ocean region). This shift in moisture flux along with associated changes in moisture convergence over landmass are found to intensify during days with extreme precipitation. These changes are expected to intensify the observed contrast in extreme precipitation over south and north India and shift the extreme precipitation southward over south Asia, causing more extreme precipitation events in the countries like Myanmar, Thailand, Malaysia, etc.</p><p><strong>Keywords:</strong> Extreme Precipitation; Indian Summer Monsoon; Climate Change; Indian Ocean Dipole.</p><p> </p><p><strong>Reference:</strong></p><p>Suman, M., Maity, R. (2020), Southward shift of precipitation extremes over south Asia: Evidences from CORDEX data. <em>Sci Rep</em> <strong>10, </strong>6452 (2020). https://doi.org/10.1038/s41598-020-63571-x.</p>

On the relationship between Indian Ocean Dipole, Indian summer monsoon and ENSO

2021 ◽  
Author(s):  
Annalisa Cherchi ◽  
Pascal Terray ◽  
Satyaban Bishoyi Ratna ◽  
Virna Meccia ◽  
Sooraj K.P.
Keyword(s):  
Indian Ocean ◽  
Summer Monsoon ◽  
Indian Summer Monsoon ◽  
Indian Ocean Dipole ◽  
Climate Models ◽  
Southern Oscillation ◽  
Global Climate ◽  
Global Climate Models ◽  
The Future ◽  
The Indian Ocean

<p>The Indian Ocean Dipole (IOD) is one of the dominant modes of variability of the tropical Indian Ocean and it has been suggested to have a crucial role in the teleconnection between the Indian summer monsoon and El Nino Southern Oscillation (ENSO). The main ideas at the base of the influence of the IOD on the ENSO-monsoon teleconnection include the possibility that it may strengthen summer rainfall over India, as well as the opposite, and also that it may produce a remote forcing on ENSO itself. The Indian Ocean has been experiencing a warming, larger than any other basins, since the 1950s. During these decades, the summer monsoon rainfall over India decreased and the frequency of Indian Ocean Dipole (IOD) events increased. In the future the IOD is projected to further increase in frequency and amplitude with mean conditions mimicking the characteristics of its positive phase. Still, state of the art global climate models have large biases in representing IOD and monsoon mean state and variability, with potential consequences for properties and related teleconnections projected in the future. This works collects a review study of the influence of the IOD on the ISM and its relationship with ENSO, as well as new results on IOD projections comparing CMIP5 and CMIP6 models.</p>

scholarly journals Moist Dynamics of Extended Monsoon Breaks over South Asia

2012 ◽  
Vol 25 (11) ◽  
pp. 3810-3831 ◽  
Author(s):  
V. Prasanna ◽  
H. Annamalai
Keyword(s):  
Indian Ocean ◽  
South Asia ◽  
Coupled Model ◽  
Equatorial Indian Ocean ◽  
Hadley Circulation ◽  
Central India ◽  
Radiative Heating ◽  
Moisture Distribution ◽  
Advection Equation ◽  
Circulation Anomalies

In the present research to identify moist processes that initiate and maintain extended monsoon breaks over South Asia moisture and moist static energy (MSE) budgets are performed on the newly available European Centre for Medium-Range Weather Forecasts Interim reanalysis (ERA-Interim) and ensemble integrations from a coupled model. The hypothesis that interaction between moist physics and regional circulation and the role of cloud–radiation feedbacks are important is tested. Budget diagnostics show that dry advection is the principal moist process to initiate extended breaks. Its sources are (i) regional anticyclonic circulation anomalies forced by equatorial Indian Ocean negative rainfall anomalies advect low MSE air from north to central India, and (ii) rainfall enhancement over tropical west Pacific forces cyclonic circulation anomalies to its northwest as a Rossby wave response, and the northerlies at the poleward flank of this circulation advect air of low MSE content from north. The dominance of anomalous wind acting on climatological moisture gradient is confirmed from an examination of the moisture advection equation. A partition of various flux terms indicates that over central India, due to an increase in upwelling shortwave and longwave fluxes, radiative cooling increases during extended breaks. Here, enhanced rainfall over the equatorial Indian Ocean promotes anomalous radiative warming due to trapping of upwelling fluxes. The differential radiative heating anchors a local Hadley circulation with descent over central India. A direct implication of this research is that observational efforts are necessary to monitor the three-dimensional moisture distribution and cloud–radiation interaction over the monsoon region that would aid in better understanding, modeling, and predicting extended monsoon breaks.

scholarly journals The Impact of Climate Change on Changing Patten of Maize Diseases in Indian Subcontinent: A Review

2021 ◽  
Author(s):  
Meena Shekhar ◽  
Nirupma Singh
Keyword(s):  
Climate Change ◽  
Plant Pathogens ◽  
Indian Subcontinent ◽  
Central India ◽  
Warming Trend ◽  
Stress Factors ◽  
North India ◽  
Stalk Rot ◽  
Favorable Conditions ◽  
The Impact

Climate change influences the occurrence, prevalence, and severity of plant pathogens. Global temperatures are predicted to rise by 2–4°C due to human activities and increased market globalization, coupled with rising temperatures, leads to a situation favorable to pest movement and establishment. Maize is an important crop after wheat and rice. Changes in rainfall distribution and temperature may result in temporary excessive soil moisture or water logging or drought in some maize producing areas leading to alterations in biotic stress factors. In Indian subcontinent warming trend in climate along the west coast, central, interior peninsula and northeast regions creates favorable conditions for diseases in maize like sorghum downy mildew (SDM) and Turcicum leaf blight (TLB). The decreasing trend of monsoon, seasonal rainfall in North India, Central India, parts of Gujarat and Kerala is suitable for post flowering stalk-rot (PFSR) which is gaining importance in maize. The outcome for any host-pathogen interaction under changing climate is not readily predictable. This review assesses the potential effects of climate change on maize pathogens and consequently on plant health. The evidence assessed indicates that climate change has already expanded pathogen’s host range and geographical distribution increasing the risk of introduction of pathogens into new areas.

scholarly journals Impact of Climate Change on Sea Surface Temperature and Chlorophyll-a Concentration in South Sukabumi Waters

2021 ◽  
Vol 19 (2) ◽  
pp. 393-398
Author(s):  
Mamat Suhermat ◽  
Muhammad Dimyati ◽  
S. Supriatna ◽  
M. Martono
Keyword(s):  
Climate Change ◽  
Indian Ocean ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Chlorophyll A ◽  
Indian Ocean Dipole ◽  
Sea Surface ◽  
Linear Regression Method ◽  
Chlorophyll A Concentration ◽  
Impact Of Climate Change

Indonesia territorial waters are very vulnerable to the impacts of climate change. Research about the variations of sea surface temperature and chlorophyll-a concentration in the southern waters of Java has been undertaken by several researchers. However, the research is still in the scope of regional scale south of Java. This research was conducted to determine the impact of climate change on sea surface temperature and chlorophyll-a concentration in Sukabumi waters. The data used consisted of IOD index anomalies, sea surface temperature and monthly chlorophyll-a concentrations from December 2002 to November 2020. Descriptive analysis was used to determine seasonal and inter-annual variability and linear regression method was used to analyze trends in changes in sea surface temperature (SST) and chlorophyll-a concentration. The results showed that the seasonal variation was influenced by the monsoon, while the interannual variation was influenced by the Indian Ocean Dipole. Climate change causes SST and chlorophyll-a concentrations to increase. In the 2003-2020 time period, SPL increased by 0.08 °C and an increase in chlorophyll-a concentration by 0.03 mg/ m3. ABSTRAKPerairan selatan Sukabumi yang berhadapan langsung dengan samudera Hindia sangat rentan terhadap dampak perubahan iklim. Penelitian mengenai variasi suhu permukaan laut dan konsentrasi klorofil-a di perairan selatan Jawa sudah dilakukan oleh beberapa peneliti sebelumnya. Namun penelitian tersebut masih dalam lingkup skala regional selatan Jawa. Penelitian ini dilakukan untuk mengetahui dampak perubahan iklim terhadap suhu permukaan laut dan konsentrasi klorofil-a di Perairan selatan Sukabumi. Data-data yang digunakan terdiri dari indeks IOD, suhu permukaan laut dan konsentrasi klorofil-a bulanan periode Desember 2002 hingga November 2020. Metode yang digunakan dalam penelitian ini adalah analisis deskripsi dan regresi linier. Hasil penelitian menunjukkan bahwa variasi musiman suhu permukaan laut dan konsentrasi klorofil-a di perairan ini dipengaruhi oleh monsun, sedangkan variasi antar tahunan dipengaruhi oleh Indian Ocean Dipole. Perubahan iklim menyebabkan suhu permukaan laut dan konsentrasi klorofil-a mengalami kenaikan. Dalam periode waktu 2003-2020 suhu permukaan laut mengalami kenaikan sebesar 0,08°C dan kenaikan konsentrasi klorofil-a sebesar 0,03 mg/m3.

The Indian summer monsoon and Indian Ocean Dipole connection in the IITM Earth System Model (IITM-ESM)

2021 ◽  
Author(s):  
A. G. Prajeesh ◽  
P. Swapna ◽  
R. Krishnan ◽  
D. C. Ayantika ◽  
N. Sandeep ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Summer Monsoon ◽  
Indian Summer Monsoon ◽  
Indian Ocean Dipole ◽  
Earth System Model ◽  
System Model ◽  
Earth System
Sign in / Sign up

Export Citation Format

Share Document