Spatiotemporal Variability of Seasonality of Rainfall Over India

Sahany, Sandeep; Mishra, Saroj K.; Pathak, Raju; Rajagopalan, Balaji

doi:10.1029/2018gl077932

Cited by 53 publications

(25 citation statements)

References 30 publications

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“…during June-September. However, the duration of the southwest monsoon rainfall over Rajasthan is very short due to late arrival and early withdrawal (Sahany et al 2018, Mehfooz et al 2005. Therefore, relative entropy is seen to be high as rainfall is concentrated in a short duration.…”

Section: Relative Entropymentioning

confidence: 99%

“…Ayoade (1988) attempted to incorporate the effect of changes in total precipitation accumulation and temporal distribution into a single metric, called rainfall seasonality. Researchers quantify rainfall seasonality in various ways by using different statistical methods (Walsh and Lawler 1981, Wilson and Dawe 2006, Adejuwon 2012, Sperber et al 2013, Feng et al 2013, Pascale et al 2015, Sahany et al 2018. For example, Walsh and Lawler (1981) investigated rainfall seasonality over the African region by linking rainfall seasonality with latitudes and they found that seasonality changes with latitudes; it is low in equatorial regions but increases rapidly with latitude.…”

Section: Introductionmentioning

confidence: 99%

“…In the context of climate change, Hasson (2016) indicated that there is a clear signal of change in observed seasonality during the period from 1951-2007, suggesting a significant decrease in precipitation regimes over most of the Indus, Western Ghats, Myanmar and eastern Tibetan Plateau, while there was a significant increase over eastern China. Sahany et al (2018) reported significant decreasing trends in seasonality coupled with decreasing rainfall during the period from 1901-2013 over parts of central India, the Indo-Gangetic plains and parts of the Western Ghats.…”

Section: Introductionmentioning

confidence: 99%

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Effects of global warming and solar geoengineering on precipitation seasonality

Bal

Pathak

Mishra

et al. 2019

Environ. Res. Lett.

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The effects of global warming and geoengineering on annual precipitation and its seasonality over different parts of the world are examined using the piControl, 4xCO 2 and G1 simulations from eight global climate models participating in the Geoengineering Model Intercomparison Project. Specifically, we have used relative entropy, seasonality index, duration of the peak rainy season and timing of the peak rainy season to investigate changes in precipitation characteristics under 4xCO 2 and G1 scenarios with reference to the piControl. In a 4xCO 2 world, precipitation is projected to increase over many parts of the globe, along with an increase in both the relative entropy and seasonality index. Further, in a 4xCO 2 world the increase in peak precipitation duration is found to be highest over the subpolar climatic region. However, over the tropical rain belt, the duration of the peak precipitation period is projected to decrease. Furthermore, there is a significant shift in the timing of the peak precipitation period by 15 days-2 months (forward) over many parts of the Northern Hemisphere except for over a few regions, such as North America and parts of Mediterranean countries, where a shift in the precipitation peak by 1-3 months (backward) is observed. However, solar geoengineering is found to significantly compensate many of the changes projected in a 4xCO 2 scenario. Solar geoengineering nullifies the precipitation increase to a large extent. Relative entropy and the seasonality index are almost restored back to that in the control simulations, although with small positive and negative deviations over different parts of the globe, thus, significantly nullifying the impact of 4xCO 2 . However, over some regions, such as northern parts of South America, the Arabian Sea and Southern Africa, geoengineering does not significantly nullify changes in the seasonality index seen in 4xCO 2 . Finally, solar geoengineering significantly compensates the changes in timing of the peak and duration of the peak precipitation seen in 4xCO 2 .

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Section: Relative Entropymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effects of global warming and solar geoengineering on precipitation seasonality

Bal

Pathak

Mishra

et al. 2019

Environ. Res. Lett.

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“…However, the temporal dynamics of productivity in relation to inter-annual variability of rainfall are more poorly resolved [2,[4][5][6][7]. In particular, how vegetated ecosystems will respond to observed and projected shifts in the mean amount and/or variability of rainfall, as well as the seasonal timing, frequency, and intensity of rainfall events (e.g., [8][9][10][11][12]) remains uncertain. Understanding how temporal patterns of rainfall influence plant productivity and growth is thus crucial for modelling and predicting vegetation responses under present or future climate conditions.…”

Section: Introductionmentioning

confidence: 99%

Tree growth responses to temporal variation in rainfall differ across a continental-scale climatic gradient

et al. 2021

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Globally, many biomes are being impacted by significant shifts in total annual rainfall as well as increasing variability of rainfall within and among years. Such changes can have potentially large impacts on plant productivity and growth, but remain largely unknown, particularly for much of the Southern Hemisphere. We investigate how growth of the widespread conifer, Callitris columellaris varied with inter-annual variation in the amount, intensity and frequency of rainfall events over the last century and between semi-arid (<500 mm mean annual rainfall) and tropical (>800 mm mean annual rainfall) biomes in Australia. We used linear and polynomial regression models to investigate the strength and shape of the relationships between growth (ring width) and rainfall. At semi-arid sites, growth was strongly and linearly related to rainfall amount, regardless of differences in the seasonality and intensity of rainfall. The linear shape of the relationship indicates that predicted future declines in mean rainfall will have proportional negative impacts on long-term tree growth in semi-arid biomes. In contrast, growth in the tropics showed a weak and asymmetrical (‘concave-down’) response to rainfall amount, where growth was less responsive to changes in rainfall amount at the higher end of the rainfall range (>1250 mm annual rainfall) than at the lower end (<1000 mm annual rainfall). The asymmetric relationship indicates that long-term growth rates of Callitris in the tropics are more sensitive to increased inter-annual variability of rainfall than to changes in the mean amount of rainfall. Our findings are consistent with observations that the responses of vegetation to changes in the mean or variability of rainfall differ between mesic and semi-arid biomes. These results highlight how contrasting growth responses of a widespread species across a hydroclimatic gradient can inform understanding of potential sensitivity of different biomes to climatic variability and change.

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“…In the second stage of analysis a pixel-wise linear trend analysis is performed on the groundwater anomaly (GW_A) estimates. Further, to evaluate the variability of precipitation over the basin an entropy-based seasonality index is applied to the IMD precipitation over the basin (Feng et al, 2013;Sahany et al, 2018).…”

Section: Methodsmentioning

confidence: 99%

Utilizing GRACE and GLDAS data for estimating groundwater storage variability over the Krishna Basin

Nair¹,

Indu²

2018

ISPRS Ann. Photogramm. Remote Sens. Spatial Inf. Sci.

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Abstract. Groundwater is utilized intensively as a source of fresh water for irrigation and human needs. Hence, it is necessary to monitor groundwater storage for water security of the region in the future. The present study aims to evaluate the groundwater resource over the Krishna basin in South India. The basin comprises of 210 major and medium irrigation projects, which makes it important to evaluate the groundwater balance for a sustainable groundwater draft. This study evaluates the trend in groundwater anomaly derived from GRACE mascon product. Results indicate that the Krishna basin is subjected to a strong decline in groundwater at a rate of 0.34cm per year. Further, the study explores the seasonality of precipitation and its effect on groundwater by adopting an entropy-based approach. Results indicate the combined effect of delay in precipitation to attain peak and reduced duration of the wet season as a primary reason for the decline in the groundwater storage. The result shows that the reduction in groundwater storage affects the evapotranspiration over the region.

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Spatiotemporal Variability of Seasonality of Rainfall Over India

Cited by 53 publications

References 30 publications

Effects of global warming and solar geoengineering on precipitation seasonality

Effects of global warming and solar geoengineering on precipitation seasonality

Tree growth responses to temporal variation in rainfall differ across a continental-scale climatic gradient

Utilizing GRACE and GLDAS data for estimating groundwater storage variability over the Krishna Basin

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