- Kerala should be ready for more extreme weather in the near future, says climate scientist
- P.S. Biju Kerala once again is in the throes of flooding and landslips triggered by extreme rainfall events which often lead to loss of lives and damage to property. As the resurgent rain has brought back memories of the worst floods in Kerala, P.S. Biju, a climate scientist of India Meteorological Department (IMD), Thiruvananthapuram, who won the best scientist award in atmospheric science in 2022 instituted by the Ministry of Earth Sciences, speaks about the challenges faced by the State. Excerpts: Climatology will not speak reality, but climate change is a reality. As Mark Twain said, “Climate is what we expect and weather is what we get”. Obviously, the number of severe weather incidences is on a steady increase in Kerala . The monsoon data of the last 120 years (1901-2020) clearly indicate that there has been a rise in temperature in this millennium (2000-2020) by more than 0.5 degree Celsius in all observatories in Kerala. However, the monsoon was deficient in the last 120 years in the State for only 17 years. There is always an 85% chance of Kerala getting a normal monsoon every year. But severe weather incidences such heavy rainfall days and thunderstorm activity have increased as a result of climate change. The fact is that if we analyse the data between 1991 to 2020 (30 years) and 1901-2010 (110 years), it can be seen that many places in Wayanad, Kasaragod, Idukki, Thrissur, Kozhikode, Ernakulam, and Kannur, the frequency of heavy rainfall has been increasing. It is true that the extreme rainfall events have increased significantly in August of late. But four years are a shorter period in climate science to reach a conclusion. However, the change I noticed during the past few years is that there was a rising trend in heat influx during the months of June and July. This is expected to draw more moisture to the atmosphere, leading to the formation of convective clouds which ultimately leads to severe weather incidents. Also read: Deep convection behind rise in rainfall intensity, says Cusat study Thunderstorm activities are reported during the monsoon as well, but not with severe lightning as in summer or Thulavarsham. In the coming years as well, thunderstorm days during the southwest monsoon may increase. Usually, during the active spell of monsoon, stratus clouds dominate over cumulonimbus clouds. That is why thunderstorm days are fewer in monsoon. But, nowadays, the presence of frequent convective clouds (cumulonimbus or thunderclouds) is also reported in the monsoon season, which is also one of the main reasons for extreme rainfall events. Now we have more than 100 automatic weather stations (AWS) in Kerala , the first State to achieve this in India. As I said earlier, we need the data from a relatively longer period to make such an assessment. However, stations such as Vythiri, Hosdurg, Kudulu, Peermade, Kunnamkulam, Kodungallur, Koyilandy, Kuttiyadi, Neryamangalam, Piravom, Aluva, Irikkur, Ayyankunnu and so on are the heavy rainfall belts. But more studies need to be done in the coming years to make a real assessment. No major change in spatial distribution or quantity of rain. In fact, the speciality of rain in Kerala is that most of the cloud condensation happens in three-four hours. Hence, 60% of the rainwater goes into the ocean without any use due to the topography of Kerala, slanting from east to west. This is not a cause for concern. But due to the increase in heavy rainfall incidences, flood situations have become frequent in the State. Of course. In a tropical country, weather prediction is more challenging than in other regions due to the fast development of weather events. The IMD is rated first in the world in weather prediction, especially in cyclone monitoring. But preparedness from all government bodies is essential to act on time on the basis of predictions by the IMD. Now we have technologies to forecast up to subdivision level, and more than 80% accuracy is reached at district-level forecast. Yes. The coming years will see similar types of extreme weather events. We have to prepare to face those events and suitable mitigation methods should be developed by all associated government bodies. Also read: Faltering rain upsets paddy crop cycles in Kerala There are many models available globally. Most of them are simply based on satellite data. IMD scientists take models only as a reference. The real forecast is based on the synoptic systems and mesoscale systems. Being the nodal agency with experience of 147 years and the presence of experts, IMD can only make the correct forecast. But any weather station periodically calibrated by IMD experts is also valid. Our code of editorial values Printable version | Aug 5, 2022 9:15:06 am | https://www.thehindu.com/news/national/kerala/climatology-will-not-speak-reality-but-climate-change-is-a-reality-says-imd-scientist-ps-biju/article65726667.ece © THG PUBLISHING PVT LTD.
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