![\"IMG_1443\"](\"https:\/\/blogs.nature.com\/indigenus\/files\/2016\/04\/IMG_1443.jpg\" "\\"IMG_1443\\"")
<\/a>{credit}S. Priyadarshini{\/credit}<\/p><\/div>\n
Scientists from the Japan Agency for Marine-Earth Science and Technology in Yokohama and India’s ministry of earth sciences have now come together to analyse the anatomy of these heatwaves<\/a>\u00a0in a paper1<\/sup> published in Scientific Reports<\/em> last week. They tried to understand what causes these severe spells of heat. They looked at\u00a0observed patterns and statistical analyses of the maximum temperature variability and have identified two types of heatwaves in the country\u00a0— the first over north-central India and the second over coastal eastern India.<\/p>\n They associate the first one over north-central India with ‘blocking’ over faraway North Atlantic, which results in a cyclonic anomaly west of North Africa at upper atmospheric levels. All of this triggers a chain of events that eventually affects the\u00a0Indian subcontinent causing heatwave conditions over India. The heatwave in coastal eastern India, on the other hand, is due to anomalous cooling in the Pacific which generates ‘northwesterly anomalies’ over the landmass reducing the land-sea breeze and resulting in heatwaves.<\/p>\n As several studies, including IPCC estimates, suggest that the\u00a0frequency of heatwaves would only increase in near future, understanding the science behind\u00a0India’s heatwaves would help policy makers design better strategies to tackle these annual extreme events.<\/p>\n In another related study2<\/sup> in Scientific Reports<\/em> last week, a group of international scientists, primarily from China and USA, have questioned\u00a0earlier estimates<\/a>\u00a0of\u00a0groundwater depletion in\u00a0the Northwest India aquifer based on data from NASA’s Gravity Recovery and Climate Experiment (GRACE) satellites. Research in the past showed that\u00a0groundwater levels in northern India have been declining very rapidly \u2014 by as much as a meter every three years \u2014 between\u00a02002 and 2008. And also that the calamity was almost entirely man-made. In\u00a0the hotbed of this unprecedented deletion are Rajasthan, Punjab, and Haryana \u2014 states with staggering population growth, rapid economic development, and water-hungry farms \u2014 accounting for about 95 percent of groundwater use in the region.<\/p>\n Last week’s study, however, says accurate ground water depletion\u00a0estimation is challenging because of ‘uncertainties in GRACE data processing’ and that earlier studies might have\u00a0overestimated the depletion\u00a0over this region. This study\u00a0highlights uncertainties in the estimates and the importance of incorporating a priori information to refine spatial patterns of GRACE signals that could be more useful in groundwater resource management.<\/p>\n Its that time of the year when mobile phone screenshots increasingly lend themselves to Facebook posts grimly declaring regional temperatures from across the country \u2014 most on the wrong side of\u00a040 and some hovering around\u00a050 in degree celsius. It\u2019s the time for the deadly heatwaves that kill thousands every year, close down schools and offices and, in general, make life miserable for millions. Read more<\/a> Continue reading \n