Climate Variability and Precipitation Dynamics in Monsoonal Regions

Monsoonal regions are characterised by seasonal reversal of winds that drive intense summer rainfall followed by a dry season. Variations in sea surface temperatures, large-scale circulations such as El Niño–Southern Oscillation and the Indian Ocean Dipole, and land–atmosphere interactions combine to modulate the onset, duration and intensity of the monsoon. Interannual and decadal changes in moisture transport, atmospheric stability and convective processes influence both the mean rainfall and the frequency of extremes. Climate change is expected to alter these dynamics through warming of the tropical troposphere, shifts in circulation patterns and changes in land cover that affect evapotranspiration. The resulting impacts on agriculture, water security and flood risk highlight the need for improved understanding of causal pathways, predictability on sub-seasonal to seasonal timescales, and robust projections under future greenhouse-gas scenarios.

Research from Nature Portfolio

Recent work has revealed that large-scale water transfer projects can inadvertently weaken monsoonal precipitation through altered land–atmosphere feedbacks. Model experiments indicate that irrigation from interconnected river basins can reduce late-season rainfall by up to 12 per cent, exacerbating post-monsoon water stress in deficit regions. Foundational research spanning six decades over central India demonstrates a threefold increase in widespread extreme rain events despite an overall decline in seasonal rainfall. This rise is linked to enhanced variability of low-level monsoon westerlies over the Arabian Sea, which drive surges of moisture inland. Further studies have shown that conversion of forest to cropland reduces evapotranspiration, diminishing the recycled component of monsoon rainfall and contributing to a long-term weakening of seasonal totals.

Climate Variability and Precipitation Dynamics in Monsoonal Regions publication trend

The graph below shows the total number of articles in climate variability and precipitation dynamics in monsoonal regions across all publications each year (not limited to Nature Index journals).

Technical terms

Monsoon circulation: Seasonal wind reversal that drives wet and dry seasons in tropical regions.

Land–atmosphere feedback: Two-way interactions between surface conditions (soil moisture, vegetation) and atmospheric processes affecting precipitation.

Moist static energy: A measure of the energy content of moist air combining sensible heat, latent heat and potential energy, used to assess atmospheric stability.

Representative Concentration Pathway (RCP): A greenhouse-gas forcing trajectory used in climate projections, denoted by the radiative forcing value in watts per square metre by 2100.

Indian Ocean Dipole: A variability mode of sea surface temperature in the Indian Ocean that influences monsoon strength and rainfall distribution.

References

1. River interlinking alters land-atmosphere feedback and changes the Indian summer monsoon. Nature Communications (2023).
2. A threefold rise in widespread extreme rain events over central India. Nature Communications (2017).
3. Weakening of Indian Summer Monsoon Rainfall due to Changes in Land Use Land Cover. Scientific Reports (2016).
4. Possible factors for the recent changes in frequency of central Indian Summer Monsoon precipitation extremes during 2005–2020. npj Climate and Atmospheric Science (2023).
5. Robust increase of Indian monsoon rainfall and its variability under future warming in CMIP6 models. Earth System Dynamics (2021).
6. The 2018 Kerala floods: a climate change perspective. Climate Dynamics (2020).