In a paper published in Nature Geoscience (paper) the authors conclude :

Declining precipitation in northern India is linked to Indian Ocean warming, suggesting a previously unrecognized teleconnection between ocean temperatures and groundwater storage.

What could be the physical explanation for such relationship . I understand that sea water intrusions can take place in coastal regions , but how does temperature come into the picture ?

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    $\begingroup$ Reading just your quote, it sounds like they are just simply implying that warm oceans -> less precipitation = less groundwater to store. So nothing as complex as direct impacts like intrusions. $\endgroup$ – JeopardyTempest Jan 11 '17 at 10:17

I think the abstract of the article addresses your question. Working backwards, it presents two direct causes of change in groundwater storage. The first is climatic - greater precipitation tends to increase storage and a decline in precipitation will reduce recharge and thus reduce storage. The second is the anthropogenic response to changes in climate (they focus on changes in precipitation but there may be a second effect of changes in air temperature). When there is less rain, more water will be pumped for irrigated agriculture.

These two effects are then related to the way the change in precipitation is affected by change in ocean temperature. So changing ocean temperature changes the rainfall amounts and patterns. The rainfall reduction in northwestern India increases the amount of groundwater pumping needed for agriculture and decreases groundwater storage.

Methods have been developed to separate the climate and pumping effects on waterlevels (Shapoori, V., et al. 2015).


Well without reading the article pointed because it costs/ no rights: warmer sea surface temperatures SST links usually with more precipitation via enhanced evaporation. But in some cases like the predicted decline in precipitation in eastern Mediterranean because of climate change happens even though warmer temperatures increase evaporation. This is simply because the changes in the intensity of average storms and changes in their storm track. The case in here seems to be similar by looking at the plotted precipitation pattern. The distribution of rain changes so that more water rains in southern India and so less water can rain in the northern parts of India. And I would guess that the total amount of precipitation has still risen.


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