Rapid Drying of Northeast India in the Last Three Decades: Climate Change or Natural Variability?

Abstract

Northeast India (NEI), the wettest place on the Earth, has experienced a rapid decrease in summer monsoon rainfall (about 355 mm) in the last 36 years (1979–2014), which has serious implications on the ecosystem and the livelihood of the people of this region. However, it is not clear whether the observed drying is due to anthropogenic activities or it is linked with the global natural variability. A diagnostic model is employed to estimate the amount of recycled rainfall, which suggests that about 7% of the total rainfall is contributed by the local moisture recycling and decrease in recycled rainfall is about 30–50 mm. Using gridded observed rainfall and sea surface temperature data of the last 114 years (1901–2014), here we show that the recent decreasing trend of NEI summer monsoon rainfall is rather associated with the strong interdecadal variability of the subtropical Pacific Ocean. The strong interdecadal variability over NEI suggests a possibility of skillful decadal prediction of the monsoon rainfall, which may have important implications in terms of long‐term planning and mitigation.

A diagnostic study of cloud physics and lightning flash rates in a severe pre‐monsoon thunderstorm over northeast India

“…The diurnal variation of rainfall is from TRMM‐3B42 hourly precipitation data, which have a spatial resolution of 0.25° × 0.25°. We use TRMM‐3B42 data instead of ground‐based rain‐gauge stations because of the fewer number of rain‐gauge stations in the hilly terrain of NEI (Choudhury et al ., ).…”

Effects of a multilayer snow scheme on the global teleconnections of the Indian summer monsoon

“…Krishnamurthy and Krishnamurthy, ; Choudhury et al . ). The decadal variability affects the monsoon through tropical Pacific variability.…”

“…Chattopadhyay et al, 2015) as well as on decadal time-scales (e.g. Krishnamurthy and Krishnamurthy, 2014;Choudhury et al, 2018). The decadal variability affects the monsoon through tropical Pacific variability.…”

Changes of Annual Precipitation and Probability Distributions for Different Climate Types of the World

“…Effect of climate change on precipitation has been studied largely on the regional scale than global scale [2,32,33]. Majority of these studies focused on finding the changes in climate extremes [25,[34][35][36]. Raghvendra et al [35] reported the increase in number and intensity of thunderstorm in the Congo Basin, Central Africa; however, the net rainfall was found to be decreased.…”

“…Thomas and Nigam [37] reported the expansion of Sahara desert, South Africa, and warming trends of Southern regions than Northern regions. Choudhary et al [36] detected a rapid decrease in monsoon rainfall in the wettest place on the earth, North-East India, in the last four decades. The changes in annual total precipitation directly affect the water budget of the regions and are crucial for maintaining adequate water resources.…”