Atmospheric Pollution Research ( IF 4.5 ) Pub Date : 2020-08-07 , DOI: 10.1016/j.apr.2020.07.026 Anoop Pakkattil , M. Muhsin , Shebin John , Aiswarya Saseendran , Arun P. Thomas , Deepa V , Ravi Varma
Atmospheric boundary layer perturbations were monitored during an annular solar eclipse event on December 26, 2019 to understand its impact on the meteorological parameters (temperature, relative humidity, wind speed, and wind direction) and trace gas concentrations (O3, NO, NO2, NH3, CO, and HONO) at Calicut (11.24° N, 75.78° E), a tropical city along the coastal belt of Arabian Sea in the southwest coast of Indian Subcontinent. The solar eclipse started at 8:05 IST (5.5 h ahead of UTC), reached to a maximum coverage of 93.28% at 09:27 IST and ends at 11:07 IST. Eclipse day data were compared with the nearby days' records from this site. The rapid fall in the irradiance caused cooling of the surface air by ~0.7 °C and weakened the wind speed, whereas the relative humidity, as expected, was increased by 5.1%. A gradual decrease in the surface O3 along with the reduction in solar irradiance was observed during the eclipse, due to the decreased efficiency in the photochemical formation of ozone. There was a decrease in mixing ratios of NO2 during the eclipse period, which was a result of the fall in ozone concentrations. No significant variation was observed in HONO levels, whereas variations in concentrations of NO and NH3 have followed the night time chemistry. The NO3 radical mixing ratios were below the detection limit during the eclipse event.
中文翻译:
在2019年12月26日的环形日食期间,在印度卡利卡特市观察到的痕量污染物波动
在2019年12月26日的环形日食事件中监测了大气边界层的扰动,以了解其对气象参数(温度,相对湿度,风速和风向)和微量气体浓度(O 3,NO,NO 2)的影响NH 3,CO和HONO)在Calicut(北纬11.24°,东经75.78°),这是印度次大陆西南沿阿拉伯海沿海带的热带城市。日食从8:05 IST开始(比UTC提前5.5小时),在09:27 IST达到最大覆盖率93.28%,在11:07 IST结束。Eclipse日数据与该站点附近日的记录进行了比较。辐照度的快速下降导致地面空气冷却了约0.7°C,并削弱了风速,而相对湿度,正如预期的那样,增加了5.1%。在日食期间,由于臭氧的光化学形成效率下降,观察到表面O 3随着太阳辐照度的降低而逐渐降低。NO 2的混合比降低在日食期间,这是臭氧浓度下降的结果。没有观察到HONO水平的显着变化,而NO和NH 3的浓度变化遵循夜间化学反应。在日食事件中,NO 3自由基混合比低于检测极限。