Lele Nikhil, Nigam Rahul, Bhattacharya Bimal K
Agriculture and Land Eco-system Division, Biological and Planetary Sciences and Applications Group, Earth, Ocean, Atmosphere Planetary Sciences and Applications Area, Space Applications Centre (ISRO), Ahmedabad, 380015, Gujarat, India.
Remote Sens Appl. 2021 Apr;22:100476. doi: 10.1016/j.rsase.2021.100476. Epub 2021 Feb 10.
The COVID 19 pandemic led to lockdown and restrictions on anthropogenic activities not only in India but all over the world. This provided an opportunity to study positive effects on environment and subsequent impact on terrestrial ecosystems such as urban, peri-urban, forest and agriculture. A variety of studies presented so far mainly include improved air quality index, water quality, reduced pollutants etc. The present study focused on few novel parameters from both polar and geostationary satellites that are not studied in context to India, and also attempts deriving/quantifying benefits rather than merely indicating qualitative improvements. Due to lack of anthropogenic activities during complete lockdown-1 (21 days from 25 March 2020) in India nighttime cooling of land surface temperature (LST) of the order of 2-6 K was observed. Amongst 10 major cities, Bhopal showed highest nighttime cooling. The cooling effect in LST was evident in 80% of industrial units distinctly indicating cooling trend. Vegetation fires were analyzed in 10 fire-prone states of India. Compared to past four-years average number of occurrences, only 45% fire occurrences occurred during lockdown, indicating strong effect of lockdown. The study also revealed that, there is increase in gross primary production in forest ecosystem to the tune of maximum 38%, during this period. Though delay in rabi crop harvest date by 1-2 weeks in majority of north Indian states was observed rise in rabi crop productivity of the order of maximum 34% was observed which is attributed to favorable environmental conditions for net carbon uptake. About 18% reduction in volumetric agricultural water demand was estimated in Indo-Gangetic region, parts of Gujarat and Rajasthan. Apart from controlling the spread of the disease, the lockdown restrictions were thus also able to show positive effects on the environment and ecosystem which might influence to rethink on strategies for sustainable development.
新冠疫情不仅在印度，而且在全球范围内导致了封锁以及对人为活动的限制。这为研究对环境的积极影响以及随后对城市、城郊、森林和农业等陆地生态系统的影响提供了契机。迄今为止呈现的各类研究主要包括空气质量指数改善、水质改善、污染物减少等。本研究聚焦于极地卫星和地球静止卫星的一些未结合印度情况进行研究的新参数，并且还尝试推导/量化益处，而非仅仅指出定性的改善。由于印度在全面封锁1（从2020年3月25日起21天）期间缺乏人为活动，观测到陆地表面温度（LST）的夜间降温幅度为2 - 6开尔文。在10个主要城市中，博帕尔夜间降温幅度最大。LST的降温效应在80%的工业单位中明显可见，清楚地表明了降温趋势。对印度10个易发生火灾的邦的植被火灾进行了分析。与过去四年的平均发生次数相比，封锁期间仅发生了45%的火灾，表明封锁的效果显著。该研究还表明，在此期间森林生态系统的总初级生产力增长了至多38%。尽管在印度北部大多数邦观察到冬季作物收获日期推迟了1 - 2周，但冬季作物生产力却出现了至多34% 的增长，这归因于有利于净碳吸收的环境条件。据估计，印度 - 恒河地区、古吉拉特邦和拉贾斯坦邦部分地区的农业用水量减少了约18%。因此，除了控制疾病传播外，封锁限制还能够对环境和生态系统产生积极影响，这可能促使人们重新思考可持续发展战略。
