scholarly journals Risk assessment of extreme Indian summer monsoon precipitation on agro-ecosystem of northern and central-east India

MAUSAM ◽  
2021 ◽  
Vol 67 (1) ◽  
pp. 143-154
Author(s):  
SOMNATH JHA ◽  
RAMESH RAGHAVA ◽  
VINAY KUMAR SEHGAL
Keyword(s):  
Summer Monsoon ◽  
Indian Summer Monsoon ◽  
Cloud Cover ◽  
Surface Wind ◽  
Standardized Precipitation Index ◽  
Precipitation Anomaly ◽  
Exceedance Probability ◽  
Drought Risk ◽  
Agricultural Practice ◽  
Gangetic Plain

Risk of extreme precipitation anomaly of Indian summer monsoon (ISM) on agro-ecosystems of Indo-Gangetic Plain (IGP) and central-east India regions has been assessed in the present study. Using monthly gridded precipitation data, standardized precipitation index (SPI) has been computed as the hazard component of the standard risk computation. The agro-ecosystems of IGP are exposed to higher risk due to extreme ISM precipitation anomaly than that of the central-east India. IGP being an irrigated region and central-east India being a rainfed region would be affected differentially due to the increasing negative anomaly in precipitation (i.e., drought risk) in the two regions. Overall the risk score and the prevalent agricultural practice suggest that the Central plateau and hill region in the rainfed region and the Upper Gangetic plain in the irrigated region are the most drought risk pone agroclimatic zones. Exceedance probability (EP) curve and the return period (RP) curve of drought risk quantification revealed that the Upper Gangetic plain of the IGP is conspicuously exposed to a higher drought risk unlike any other region. Increasing drought risk is coupled with increasing cloud cover in Upper Gangetic plain. Surface wind, temperature or the outgoing longwave radiation of this zone could not completely explain the cause of this risk. Changing role of average aerosol index (AAI) hinted to the presence of aerosol altered cloud micro-system in Upper Gangetic plain and may be one of the major reasons for increasing non-precipitating cloud in this zone and thus contributing to the drought risk even with increasing cloud cover trend.

The Apparent Water Vapor Sinks and Heat Sources Associated with the Intraseasonal Oscillation of the Indian Summer Monsoon

2011 ◽  
Vol 24 (16) ◽  
pp. 4466-4479 ◽  
Author(s):  
Sun Wong ◽  
Eric J. Fetzer ◽  
Baijun Tian ◽  
Bjorn Lambrigtsen ◽  
Hengchun Ye
Keyword(s):  
Remote Sensing ◽  
Water Vapor ◽  
Heat Source ◽  
Summer Monsoon ◽  
Indian Summer Monsoon ◽  
Intraseasonal Oscillation ◽  
Precipitation Anomaly ◽  
Specific Humidity ◽  
Heat Sources ◽  
Test Bed

Abstract The possibility of using remote sensing retrievals to estimate apparent water vapor sinks and heat sources is explored. The apparent water vapor sinks and heat sources are estimated from a combination of remote sensing, specific humidity, and temperature from the Atmospheric Infrared Sounder/Advanced Microwave Sounding Unit (AIRS) and wind fields from the National Aeronautics and Space Administration (NASA)’s Goddard Space Flight Center (GSFC)’s Modern Era Retrospective-Analysis for Research and Applications (MERRA). The intraseasonal oscillation (ISO) of the Indian summer monsoon is used as a test bed to evaluate the apparent water vapor sink and heat source. The ISO-related northward movement of the column-integrated apparent water vapor sink matches that of precipitation observed by the Tropical Rainfall Measuring Mission (TRMM) minus the MERRA surface evaporation, although the amplitude of the variation is underestimated by 50%. The diagnosed water vapor and heat budgets associated with convective events during various phases of the ISO agree with the moisture–convection feedback mechanism. The apparent heat source moves northward coherently with the apparent water vapor sink associated with the deep convective activity, which is consistent with the northward migration of the precipitation anomaly. The horizontal advection of water vapor and dynamical warming are strong north of the convective area, causing the northward movement of the convection by the destabilization of the atmosphere. The spatial distribution of the apparent heat source anomalies associated with different phases of the ISO is consistent with that of the diabatic heating anomalies from the trained heating (TRAIN Q1) dataset. Further diagnostics of the TRAIN Q1 heating anomalies indicate that the ISO in the apparent heat source is dominated by a variation in latent heating associated with the precipitation.

scholarly journals Effects of winter and summer-time irrigation over Gangetic Plain on the mean and intra-seasonal variability of Indian summer monsoon

2019 ◽  
Vol 53 (5-6) ◽  
pp. 3147-3166 ◽  
Author(s):  
Shubhi Agrawal ◽  
Arindam Chakraborty ◽  
Nirupam Karmakar ◽  
Simon Moulds ◽  
Ana Mijic ◽  
...  
Keyword(s):  
Summer Monsoon ◽  
Indian Summer Monsoon ◽  
Seasonal Variability ◽  
Gangetic Plain ◽  
The Mean ◽  
Summer Time

scholarly journals Altitude profiles of CCN characteristics across the Indo-Gangetic Plain prior to the onset of the Indian summer monsoon

2019 ◽  
Author(s):  
Venugopalan Nair Jayachandran ◽  
Surendran Nair Suresh Babu ◽  
Aditya Vaishya ◽  
Mukunda M. Gogoi ◽  
Vijayakumar S. Nair ◽  
...  
Keyword(s):  
Optical Properties ◽  
Summer Monsoon ◽  
Indian Summer Monsoon ◽  
Empirical Relation ◽  
Anthropogenic Sources ◽  
Arid Environments ◽  
Aerosol Optical Properties ◽  
Gangetic Plain ◽  
Activation Efficiency ◽  
Indo Gangetic Plain

Abstract. Concurrent measurements of the altitude profiles of cloud condensation nuclei (CCN) concentration, as a function of supersaturation (ranging from 0.2 % to 1.0 %), and aerosol optical properties (scattering and absorption coefficients) were carried out aboard an instrumented aircraft across the Indo-Gangetic Plain (IGP) covering coastal, urban and arid environments, just prior to the onset of the Indian summer monsoon (ISM) of 2016, under the aegis of the SWAAMI - RAWEX campaign. In general, the CCN concentration has been highest in the Central IGP, decreasing spatially from east to west above the planetary boundary layer (PBL), which is ~ 1.5 km for the IGP during pre-monsoon. Despite of this, the CCN activation efficiency at 0.4 % supersaturation has been, interestingly, the highest over the eastern IGP (~ 72 %), followed by the west (~ 61 %), and has been the least over the central IGP (~ 24 %) within the PBL. In general, higher activation efficiency is noticed above the PBL than below it. The Central IGP showed remarkably low CCN activation efficiency at all the heights, which appears to be associated with high black carbon (BC) mass concentration there, indicating the role of anthropogenic sources in suppressing the CCN efficiency. First ever CCN measurements over the western IGP, encompassing "The Great Indian desert", show high CCN efficiency, ~ 61 % at 0.4 % supersaturation, indicating hygroscopic nature of the dust. The vertical structure of CCN properties is found to be airmass-dependent; with higher activation efficiency even over the central IGP during the prevalence of marine airmass. Precipitation episodes seem to reduce the CCN activation efficiency below cloud level. An empirical relation has emerged between the CCN concentration and the scattering aerosol index (AI), which would facilitate prediction of CCN from aerosol optical properties.

scholarly journals Correction to: Effects of winter and summer-time irrigation over Gangetic Plain on the mean and intra-seasonal variability of Indian summer monsoon

2019 ◽  
Vol 53 (9-10) ◽  
pp. 6519-6519 ◽  
Author(s):  
Shubhi Agrawal ◽  
Arindam Chakraborty ◽  
Nirupam Karmakar ◽  
Simon Moulds ◽  
Ana Mijic ◽  
...  
Keyword(s):  
Summer Monsoon ◽  
Indian Summer Monsoon ◽  
Seasonal Variability ◽  
Gangetic Plain ◽  
The Mean ◽  
Summer Time

scholarly journals Trend of standardized precipitation index during Indian summer monsoon season in agroclimatic zones of India

2013 ◽  
Vol 4 (1) ◽  
pp. 429-449 ◽  
Author(s):  
S. Jha ◽  
V. K. Sehgal ◽  
R. Raghava ◽  
M. Sinha
Keyword(s):  
Summer Monsoon ◽  
Monsoon Season ◽  
Standardized Precipitation Index ◽  
Precipitation Index ◽  
Trend Test ◽  
Monthly Precipitation ◽  
Summer Monsoon Season ◽  
Central Plateau ◽  
Gangetic Plain ◽  
Agroclimatic Zones

Abstract. Standardized precipitation index (SPI) was computed with CRU TS3.0 gridded 0.5 × 0.5° monthly precipitation dataset for each of the 14 mainland agroclimatic zones (ACZs) of India for individual months (June, July, August and September) and season (JJAS) of summer monsoon for 56 yr (1951–2006). Mann Kendall Trend Test with the representative SPI of the ACZs shows that only six out of 14 mainland ACZs have a significant trend during summer monsoon. Trans-Gangetic plain significantly gains wetness during the month of June. West coast plain and hill has a typical feature of significant increasing trend of wetness during June and increasing dryness during July. In general Upper Gangetic plain, Middle Gangetic plain, Central plateau and hill and Eastern plateau and hill have a significantly increasing drying trend during the whole duration of summer monsoon season.

Atmospheric Hydrology of the Anomalous 2002 Indian Summer Monsoon

2005 ◽  
Vol 133 (10) ◽  
pp. 2996-3014 ◽  
Author(s):  
J. Fasullo
Keyword(s):  
Summer Monsoon ◽  
Indian Summer Monsoon ◽  
El Niño ◽  
Arabian Sea ◽  
El Nino ◽  
Monsoon Season ◽  
Surface Wind ◽  
Enso Events ◽  
Major Break ◽  
The Impact

Abstract The 2002 Indian summer monsoon season is unique because of its exceptional weakness, its association with a relatively weak El Niño, and its precedence by over a decade in which ENSO events fail to be associated with significant monsoon anomalies. In this study, atmospheric hydrology during the 2002 summer monsoon and its relationship to monsoon seasons accompanying El Niño events since 1948 are assessed using reanalysis and satellite fields. Strong hydrologic deficits are identified for July and September 2002. During July, the impact of the disturbed Hadley and Walker circulations in the African and Indian Ocean region on vertically integrated moisture transport (VIMT) in the Arabian Sea and India is found to be key to the Indian drought. Interhemispheric coherence in satellite-derived surface wind anomalies is also identified. During September, VIMT and surface wind anomalies, both to the east and west of India, contribute to anomalous moisture divergence in India. Bay of Bengal SST and Indian CAPE anomalies are found to act in response to the season’s major break episodes, contrary to other studies that suggest their role as instigators of break periods. The 2002 season is also found to exhibit characteristics that are common to other recent weak monsoons accompanying El Niño, such as strong westerly VIMT anomalies in the western Pacific Ocean and easterly VIMT anomalies in the Arabian Sea. Hydrologic anomalies that distinguish many recent normal monsoon seasons coinciding with El Niño from the El Niño distribution overall are not evident in 2002. In many respects, the 2002 season thus represents a reemergence of the hydrologic anomalies that have accompanied a strong monsoon–ENSO teleconnection over the past 50 yr and may present a challenge for perspectives that suggest a lasting decoupling of the monsoon–ENSO systems.

scholarly journals Altitude profiles of cloud condensation nuclei characteristics across the Indo-Gangetic Plain prior to the onset of the Indian summer monsoon

2020 ◽  
Vol 20 (1) ◽  
pp. 561-576 ◽  
Author(s):  
Venugopalan Nair Jayachandran ◽  
Surendran Nair Suresh Babu ◽  
Aditya Vaishya ◽  
Mukunda M. Gogoi ◽  
Vijayakumar S. Nair ◽  
...  
Keyword(s):  
Optical Properties ◽  
Summer Monsoon ◽  
Indian Summer Monsoon ◽  
Cloud Condensation Nuclei ◽  
Condensation Nuclei ◽  
Aerosol Optical Properties ◽  
Gangetic Plain ◽  
Air Mass ◽  
Activation Efficiency ◽  
Indo Gangetic Plain

Abstract. Concurrent measurements of the altitude profiles of the concentration of cloud condensation nuclei (CCN), as a function of supersaturation (ranging from 0.2 % to 1.0 %), and aerosol optical properties (scattering and absorption coefficients) were carried out aboard an instrumented aircraft across the Indo-Gangetic Plain (IGP) just prior to the onset of the Indian summer monsoon (ISM) of 2016. The experiment was conducted under the aegis of the combined South-West Asian Aerosol–Monsoon Interactions and Regional Aerosol Warming Experiment (SWAAMI–RAWEX) campaign. The measurements covered coastal, urban and arid environments. In general, the CCN concentration was highest in the central IGP, decreasing spatially from east to west above the planetary boundary layer (PBL), which is ∼1.5 km for the IGP during pre-monsoon period. Despite this, the CCN activation efficiency at 0.4 % supersaturation was, interestingly, the highest over the eastern IGP (∼72 %), followed by that in the west (∼61 %), and it was the least over the central IGP (∼24 %) within the PBL. In general, higher activation efficiency is noticed above the PBL than below it. The central IGP showed remarkably low CCN activation efficiency at all altitudes, which appears to be associated with high black carbon (BC) mass concentration there, indicating the role of anthropogenic sources in suppressing the CCN efficiency. These first-ever CCN measurements over the western IGP, encompassing “the Great Indian Desert” also known as “the Thar Desert”, showed high CCN efficiency, ∼61 % at 0.4 % supersaturation, indicating the hygroscopic nature of the dust. The vertical structure of CCN properties is found to be air mass dependent, with higher activation efficiency even over the central IGP during the prevalence of marine air mass. Wet scavenging associated with precipitation episodes seems to have reduced the CCN activation efficiency below cloud level. An empirical relation has emerged between the CCN concentration and the scattering aerosol index (AI), which would facilitate the prediction of CCN from aerosol optical properties.

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