Rainfall and temperature trends in India

Abstract

An investigation was carried out to identify trends in the rainfall and temperature regimes of the Ganga basin in India and in India as a whole. Long-term data on the monsoon and annual rainfall and the average annual temperature for India as a whole, and on the monsoon rainfall, number of rainy days and annual maximum temperature of the Ganga basin were analysed. The trends in these data were detected using non-parametric methods. The results of this study showed that the rainfall variables had a decreasing trend and the temperature had an increasing trend. These trends were observed to have begun around the second half of the 1960s, and have implications for the Indian economy. As the Indian economy continues to be based on agriculture, water resource management for irrigation plays a vital part in its growth. Present methods of design and management for water resource systems assume the climatic regime to be stationary. If indeed the climatic regime has changed, it will be necessary to develop new management approaches which consider this change.

Maximum Temperature Trends in the Himalaya and Its Vicinity: An Analysis Based on Temperature Records from Nepal for the Period 1971–94

“…The temperature trends found in the Kathmandu record are similar to those in the Tibetan Plateau, which showed decrease in temperature from the 1950s to the 1970s and warming thereafter (Li and Tang 1986). Warming after 1965 was also observed in temperature records from the Ganges basin in India (Kothyari and Shing 1996). The temperature trend of India as a whole, however, is different as it shows low and constant warming over the whole century, lacking the cooling around the 1940s and the distinct warming after the 1970s (Hingane et al 1985).…”

Maximum Temperature Trends in the Himalaya and Its Vicinity: An Analysis Based on Temperature Records from Nepal for the Period 1971–94

“…The temperature trends found in the Kathmandu record are similar to those in the Tibetan Plateau, which showed decrease in temperature from the 1950s to the 1970s and warming thereafter (Li and Tang 1986). Warming after 1965 was also observed in temperature records from the Ganges basin in India (Kothyari and Shing 1996). The temperature trend of India as a whole, however, is different as it shows low and constant warming over the whole century, lacking the cooling around the 1940s and the distinct warming after the 1970s (Hingane et al 1985).…”

Analysis of trends in rainfall and dry/wet years over a century in the Eastern Ganga Canal command

“…This reveals that the weighted mean annual rainfall of the command area is decreasing at a rate of 10.2 mm/decade and the weighted mean monsoonal rainfall is decreasing at 10.6 mm/decade. The nature of the decreasing trend in annual as well as monsoonal rainfall in the command area is in agreement with previous studies (e.g., Kothyari and Singh, ; Kothyari et al, ; Jain and Kumar, ). However, many of these studies have brought out contradictory results regarding the trend of rainfall over the Ganga basin.…”

“…However, many of these studies have brought out contradictory results regarding the trend of rainfall over the Ganga basin. For example, Kothyari and Singh () found a decreasing trend in monsoon rainfall and rainy days in the Ganga basin, whereas Singh and Sontakke () after analysing rainfall data for the period 1829–1999 over the Indo‐Gangetic Plains concluded that the western parts of the Indo‐Gangetic Plains, where the present study area is located, experience a significant increasing trend (17.0 mm/decade) in the monsoon rainfall. The majority of studies agree with the conclusion that the Ganga basin has experienced both statistically significant/insignificant decreasing trends in monsoon and/or annual rainfall, although a consensus over the value of the trend has not been reached (Kothyari and Singh, ; Kothyari et al, ; Singh and Sontakke, ; IINC, ; Kumar and Jain, ; Jain and Kumar, ).…”

Global trend analysis of the MODIS drought severity index

“…Since the Indian Peninsula is a "water-limited" area considering long- term evaporation (McVicar et al, 2012), precipitation tendencies might play a key role in interpreting DSI shifts. Kothyari and Singh (1996) studied long-term time series of summer monsoon rainfall and identified decadal departures above and below the long time average alternatively for three consecutive decades. Singh and Sontakke (2002) reported on an increase in extreme rainfall events over northwest India during the summer monsoon and a decline of the number of rainy days along east coastal stations in the past decades, resulting in a westward shift in rainfall activities.…”

Maximum Temperature Trends in the Himalaya and Its Vicinity: An Analysis Based on Temperature Records from Nepal for the Period 1971–94

“…The temperature trends found in the Kathmandu record are similar to those in the Tibetan Plateau, which showed decrease in temperature from the 1950s to the 1970s and warming thereafter (Li and Tang 1986). Warming after 1965 was also observed in temperature records from the Ganges basin in India (Kothyari and Shing 1996). The temperature trend of India as a whole, however, is different as it shows low and constant warming over the whole century, lacking the cooling around the 1940s and the distinct warming after the 1970s (Hingane et al 1985).…”

Analysis of trends in rainfall and dry/wet years over a century in the Eastern Ganga Canal command

“…This reveals that the weighted mean annual rainfall of the command area is decreasing at a rate of 10.2 mm/decade and the weighted mean monsoonal rainfall is decreasing at 10.6 mm/decade. The nature of the decreasing trend in annual as well as monsoonal rainfall in the command area is in agreement with previous studies (e.g., Kothyari and Singh, ; Kothyari et al, ; Jain and Kumar, ). However, many of these studies have brought out contradictory results regarding the trend of rainfall over the Ganga basin.…”

“…However, many of these studies have brought out contradictory results regarding the trend of rainfall over the Ganga basin. For example, Kothyari and Singh () found a decreasing trend in monsoon rainfall and rainy days in the Ganga basin, whereas Singh and Sontakke () after analysing rainfall data for the period 1829–1999 over the Indo‐Gangetic Plains concluded that the western parts of the Indo‐Gangetic Plains, where the present study area is located, experience a significant increasing trend (17.0 mm/decade) in the monsoon rainfall. The majority of studies agree with the conclusion that the Ganga basin has experienced both statistically significant/insignificant decreasing trends in monsoon and/or annual rainfall, although a consensus over the value of the trend has not been reached (Kothyari and Singh, ; Kothyari et al, ; Singh and Sontakke, ; IINC, ; Kumar and Jain, ; Jain and Kumar, ).…”

Global trend analysis of the MODIS drought severity index

“…Since the Indian Peninsula is a "water-limited" area considering long- term evaporation (McVicar et al, 2012), precipitation tendencies might play a key role in interpreting DSI shifts. Kothyari and Singh (1996) studied long-term time series of summer monsoon rainfall and identified decadal departures above and below the long time average alternatively for three consecutive decades. Singh and Sontakke (2002) reported on an increase in extreme rainfall events over northwest India during the summer monsoon and a decline of the number of rainy days along east coastal stations in the past decades, resulting in a westward shift in rainfall activities.…”

Maximum Temperature Trends in the Himalaya and Its Vicinity: An Analysis Based on Temperature Records from Nepal for the Period 1971–94

“…The temperature trends found in the Kathmandu record are similar to those in the Tibetan Plateau, which showed decrease in temperature from the 1950s to the 1970s and warming thereafter (Li and Tang 1986). Warming after 1965 was also observed in temperature records from the Ganges basin in India (Kothyari and Shing 1996). The temperature trend of India as a whole, however, is different as it shows low and constant warming over the whole century, lacking the cooling around the 1940s and the distinct warming after the 1970s (Hingane et al 1985).…”

Analysis of trends in rainfall and dry/wet years over a century in the Eastern Ganga Canal command

“…This reveals that the weighted mean annual rainfall of the command area is decreasing at a rate of 10.2 mm/decade and the weighted mean monsoonal rainfall is decreasing at 10.6 mm/decade. The nature of the decreasing trend in annual as well as monsoonal rainfall in the command area is in agreement with previous studies (e.g., Kothyari and Singh, ; Kothyari et al, ; Jain and Kumar, ). However, many of these studies have brought out contradictory results regarding the trend of rainfall over the Ganga basin.…”

“…However, many of these studies have brought out contradictory results regarding the trend of rainfall over the Ganga basin. For example, Kothyari and Singh () found a decreasing trend in monsoon rainfall and rainy days in the Ganga basin, whereas Singh and Sontakke () after analysing rainfall data for the period 1829–1999 over the Indo‐Gangetic Plains concluded that the western parts of the Indo‐Gangetic Plains, where the present study area is located, experience a significant increasing trend (17.0 mm/decade) in the monsoon rainfall. The majority of studies agree with the conclusion that the Ganga basin has experienced both statistically significant/insignificant decreasing trends in monsoon and/or annual rainfall, although a consensus over the value of the trend has not been reached (Kothyari and Singh, ; Kothyari et al, ; Singh and Sontakke, ; IINC, ; Kumar and Jain, ; Jain and Kumar, ).…”

Global trend analysis of the MODIS drought severity index

“…Since the Indian Peninsula is a "water-limited" area considering long- term evaporation (McVicar et al, 2012), precipitation tendencies might play a key role in interpreting DSI shifts. Kothyari and Singh (1996) studied long-term time series of summer monsoon rainfall and identified decadal departures above and below the long time average alternatively for three consecutive decades. Singh and Sontakke (2002) reported on an increase in extreme rainfall events over northwest India during the summer monsoon and a decline of the number of rainy days along east coastal stations in the past decades, resulting in a westward shift in rainfall activities.…”