Peninsular India was actually cooler while the northern parts of the country experienced temperature differences normally associated with the polar regions of the world
The pre-monsoon has, in the last couple of days, brought the mercury down. However, heatwave-like conditions in April across India got people talking about how hotter-than-normal April 2022 was.
Down To Earth accessed land surface data recorded by the National Aeronautics and Space Administration (NASA) for the month of April. An analysis of the data showed that peninsular India was actually cooler while the northern parts of the country experienced temperature differences normally associated with the polar regions of the world.
In fact, the northern parts India, Pakistan and Afghanistan were actually hotter than the Sahara — across Niger and Chad — based on land surface temperature difference or anomaly, when compared to average April temperature from 2001 to 2010.
Land surface temperature, according to NASA, means “how hot or cold the ground feels to the touch”. So, if there is an anomaly of difference, it means the surface temperature of the Earth is either warmer or cooler.
Peninsular India (as seen in the map) was cooler compared to the 2001 to 2010 average, while north India was much warmer.
This variation in temperature difference, according to the India Meteorological Division (IMD) April summary report, was because of southern peninsular India — especially Kerala and Tamil Nadu — receiving “scattered to widespread rainfall and thunderstorms”.
Simultaneously, the absence of western disturbances in April led to a prolonged spell of heatwave-like days and above normal temperature across the northwest and central parts of the country.
Western disturbances refer to low pressure areas created outside the tropical regions — mostly the Mediterranean Sea and Atlantic Ocean — which cause rainfall during the winter and pre-monsoon season in India.
The average mean temperature for April in northwest and central India was the highest since 1901, according to IMD. It was the 17th-warmest for peninsular India while across India, it was the second-highest.
Apart from tangible impacts and losses like the coal shortage which led to a power crisis and crop damages due to heatwaves in April, from a climatological perspective, such temperature anomalies are normally experienced in the polar regions — the Arctic and the Antarctic.
The polar regions are warming at a much faster rate compared to the other continents. But land surface data for April clearly shows some regions in north India — Ladakh and eastern parts of Himachal Pradesh — are warming at least 12°C above the 2001 to 2010 average.
This is happening during the summer when temperature, in general, is higher than rest of the year, resulting in the difference in temperature.
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