A study of cloud vertical structure over Delhi using long-term radiosonde data

Abstract

The vertical structure of clouds significantly influences the local scale atmospheric stability and radiative forcing over any place. Over Indian region there is a notable lack of thorough and long term studies on Cloud vertical structure (CVS). Therefore, we tried to study CVS over Delhi which is one of the most important urban site having high population density and is one of the most polluted megacity of India. The local scale meteorology and atmospheric dynamics are significantly different in Delhi as compared to surrounding rural areas. Delhi has been witnessing odd precipitation trends from last two decades and has also become one of the most water scarce regions in country. The understanding of all of these crises could be improved with a long term study of CVS over Delhi. We have done seasonal comparison using long term (2000-2019) radiosonde data. We found that the frequency of multi-layer clouds is significantly higher in monsoon season as compared to other season. The frequency of high-level clouds is also significantly higher followed by low-level and middle-level clouds except in pre-monsoon where the frequency of lowlevel clouds is notably lower. We haven’t detected any deep convective and low-level convective cloud in pre-monsoon and post-monsoon season. The average cloud base and cloud top height are found to be significantly higher in premonsoon season for single, double as well as triple layer clouds whereas these clouds were thinnest in post-monsoon with cloud base lying very low for triple layer clouds.