Association of Cloud Vertical Structure and Aerosols studied over Delhi
Megacity.
Abstract
The understanding of the atmospheric dynamics and thermodynamics in the
time of climate change has become an unavoidable necessity for survival
of humanity. We need to fill the research gaps with a more thorough and
urgent research approach in the required domains. One of a major
research gap whose filling could enrich our understanding of atmospheric
dynamics and hydrological cycle is the vertical structure and
distribution of cloud in atmosphere. Cloud vertical structure (CVS)
significantly influences the quantity of solar radiation coming inside
the atmosphere of Earth and thus it modulates the atmospheric adiabatic
heating. It has also been found to be the major source of uncertainties
in the global climate and weather models. In India the rural population
is shifting to urbanized areas which are hub of intense economic
activities and have high level of pollution. We witness high loading of
anthropogenic aerosol in these highly urbanized areas which also varies
seasonally. The association of these aerosols concentration with CVS has
not been studied so far. Delhi is one of such large urban settlement and
is also the most polluted Indian megacity. Therefore we have studied the
CVS over Delhi using multi-year radiosonde and active satellite based
data and also correlated it with aerosols concentration in the same
region. The study includes a time series analysis of cloud base and top
height with co-temporal and co-spatial AOD values for low-level,
middle-level and high-level clouds. Significant trend in variation of
cloud base and top height is found in our study. We have done the
seasonal comparison of aerosols concentration with the CVS. And the
study is showing that aerosols are influencing the CVS to a notable
extent. The cloud vertical structure and aerosols also significantly
influences the atmospheric temperature and the precipitation pattern and
thus the hydrological cycle .Therefore, the effect of aerosol on clouds
vertical structure in these polluted megacities could be very helpful
for future climate projection and for understanding the hydrological
cycle in these areas.