Spatio-temporal variability of rainfall regime in the Brahmaputra valley of North East India

Deka, R. L.; Mahanta, Chitralekha; Nath, Kedar; Dutta, Mrinal Kanti

doi:10.1007/s00704-015-1452-8

Cited by 29 publications

(23 citation statements)

References 36 publications

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“…Despite decrease in PWV and CER, the observed slow increasing trends of annual RR at TWN (0.003 year −1 ) and DAC (0.007 year −1 ) is attributed to the increase in rainfall during all the seasons, except winter over those locations. Such increasing trends of rainfall in Bangladesh have also been reported by Shahid (2010) The monsoon rainfall over India was less by 4.5% in recent decades compared to the earlier period 1949-1979(Ranade et al, 2008Deka et al, 2016). A significant decreasing trend in moderate rainfall and increase in heavy rainfall events in monsoon had been observed in this region for the period 1975period -2006period by Goswami et al (2010.…”

Section: Effect Of Aerosols On Cod and Rainfallmentioning

confidence: 53%

“…The monsoon rainfall over India was less by 4.5% in recent decades (1979–2006) compared to the earlier period 1949–1979 (Ranade et al, ; Deka et al, ). A significant decreasing trend in moderate rainfall and increase in heavy rainfall events in monsoon had been observed in this region for the period 1975–2006 by Goswami et al .…”

Section: Resultsmentioning

confidence: 96%

“…Earlier, Deka et al . () have attributed the declining rainfall trend over this region to the decreasing trend in convective available potential energy (CAPE) and increasing convective inhibition energy (CIE). The present attribution of declining RR trends to the increasing aerosol loading, and thus CCN, is in line with that of Turner and Annamalai (), which is partly due to the effect of BC and other anthropogenic aerosols resulting from industrialization and land‐use changes in this region.…”

Section: Resultsmentioning

confidence: 99%

“…() in NER and in the state of Assam by Deka et al . (). However, contributions by aerosols to the change in rainfall pattern have not been included in their investigations.…”

Section: Introductionmentioning

confidence: 99%

“…Reports on significant increases in the frequency of extreme rainfall events and a reduction in low and moderate events in the summer monsoon over Meghalaya Plateau, including Cherrapunji, are available (Prokop and Walanus, 2014, and references therein). Further, decreasing trends of monsoon precipitation have been reported by Konwar et al (2012) in NER and in the state of Assam by Deka et al (2016). However, contributions by aerosols to the change in rainfall pattern have not been included in their investigations.…”

Section: Introductionmentioning

confidence: 99%

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Aerosols characteristics, trends and their climatic implications over Northeast India and adjoining South Asia

Dahutia

Pathak

Bhuyan

2017

Intl Journal of Climatology

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Aerosol characteristics and climatic implications derived for selected locations of the north‐eastern region of India and adjoining locations Thimphu (THM), Dhaka (DAC) and Banmauk between 22–30°N and 88–98°E are reported. The region is found to reveal a distinct spatio‐temporal variability in aerosol distribution, with highest climatological mean aerosol optical depth at 550 nm (AOD550) at DAC (0.65 ± 0.07) and lowest at the high altitude location THM (0.19 ± 0.02). Seasonally the maximum AOD550 is observed in the pre‐monsoon season. Moderate resolution imaging spectroradiometer Level‐3 Collection 6 AOD550 and Ångström exponent (AE) exhibit a significant and simultaneous increasing trend in the range of ∼0.003 year−1 to 0.012 year−1 and ∼−0.001 year−1 to 0.020 year−1, respectively, during the period 2001–2014. Together with AE, increasing trend of total ozone mapping spectrometer and ozone monitoring instrument‐retrieved aerosol index (∼0.001 year−1 to 0.007 year−1 during 1979–2014) signifies an increase in anthropogenic aerosol loading, leading to an increase in number density of cloud condensation nuclei and decrease/increase of cloud effective radius /cloud optical depth (COD). This is further associated with overall decreasing trends of rainfall rate over this complex monsoon region. A slow increase in maximum temperature (Tmax) (∼0.008 °C year−1 to 0.049 °C year−1) compared to that in minimum temperature (Tmin) (∼0.007 °C year−1 to 0.068 °C year−1) is attributed to solar dimming due to increasing aerosol loading and COD (∼0.056 year−1 to 0.15 year−1). A decrease in high‐level cloud (CODhigh) counteracts decreasing trends of ground reaching solar radiation over a few locations, including Dibrugarh. This study is important from an aerosol radiation interaction and aerosol cloud interaction viewpoint, which facilitates in reaching a closure of model simulated present day climate change and future climate projections.

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Section: Effect Of Aerosols On Cod and Rainfallmentioning

confidence: 53%

Section: Resultsmentioning

confidence: 96%

Section: Resultsmentioning

confidence: 99%

“…() in NER and in the state of Assam by Deka et al . (). However, contributions by aerosols to the change in rainfall pattern have not been included in their investigations.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Aerosols characteristics, trends and their climatic implications over Northeast India and adjoining South Asia

Dahutia

Pathak

Bhuyan

2017

Intl Journal of Climatology

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Understanding satellite‐derived groundwater dynamics and its association with hydrological processes over India during excess and deficit monsoon years

Shaikh,

Parekh,

Gnanaseelan

2024

Hydrological Processes

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The Gravity Recovery and Climate Experiment (GRACE) satellite provides valuable data to monitor groundwater variation. This study investigates groundwater dynamics in India during deficit and excess monsoon years. It finds possible interactions by exploring how groundwater levels respond to meteorological and hydrological conditions. Groundwater anomalies (GWA) are estimated using Terrestrial Water Storage Anomalies (TWSA) from GRACE and hydrological parameters from the Global Land Data Assimilation System (GLDAS). The statistical analysis reveals that the standard deviation is higher for hydrological parameters in summer (June to September), whereas it is higher in fall (October to November) for GWA in many parts of India. The modulation in hydrological parameters subsequently impacts GWA during the following seasons. The study reports increased groundwater across many parts of India during fall. However, groundwater decline is closely linked to unsaturated soil moisture from fall to winter (December to February). Groundwater storage is at its lowest levels during the following spring (March to May) over India. Four deficit and three excess summer monsoons occurred from 2002 to 2022. Composite analysis of GWA reveals that there is replenishment (depletion) of groundwater during the following fall and winter in excess (deficit). The analysis based on extreme deficit monsoon years (2002, 2009) and excess monsoon year (2019) reveals that during the deficit years, groundwater recharge is less, and excess monsoon year it is more; and is vice versa for GWA. The study reports decline in GWA during the summer 2019, which is attributed to the hydrological conditions of the preceding year and modulation of the hydrological processes. As climate variability and water scarcity become increasingly pressing issues, understanding the relationships between hydrological factors and groundwater dynamics is essential for ensuring sustainable water use and resilience to extremely varying climate conditions.

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The changing characteristics of rainfall over the Brahmaputra Basin during 1998–2018

Gogoi

Vinoj

Landu

et al. 2023

Quart J Royal Meteoro Soc

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The changes to the hydrological cycle as a consequence of climate change significantly affect the water security of countries worldwide. The Brahmaputra Basin (BB), a biodiversity hotspot, is among the world's wettest regions and is vulnerable to climate change. Using ground and satellite-based datasets from multiple sources and a percentile-based analysis from 1998 to 2018, it is found that an asymmetric trend exists in extreme rainfall over the hills and the adjacent plains of the basin. The hills experience a decline in rainfall, whereas, over the plains, an increase is observed on similar rainfall days. During 1998-2018, mean accumulated rainfall over the whole basin declined by as much as ∼60% during the October to December (OND) period. Similarly, a decline of ∼20% is observed for June to September (JJAS). The most significant reduction in mean rainfall was mainly over the wettest regions of the basin, such as Cherrapunji/Mawsynram and is concentrated in the highest percentile (extreme events) of rainfall distribution. Such an overall decline in total rainfall coupled with altitudinal asymmetry in percentile distributions of rainfall may contribute towards flood hazards with changing lead time for warning, posing severe socio-economic challenges.

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Spatio-temporal variability of rainfall regime in the Brahmaputra valley of North East India

Cited by 29 publications

References 36 publications

Aerosols characteristics, trends and their climatic implications over Northeast India and adjoining South Asia

Aerosols characteristics, trends and their climatic implications over Northeast India and adjoining South Asia

Understanding satellite‐derived groundwater dynamics and its association with hydrological processes over India during excess and deficit monsoon years

The changing characteristics of rainfall over the Brahmaputra Basin during 1998–2018

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