Complex physical mechanisms associated with Mesoscale Convective System
over South-east India using collocated high-resolution Observations
Abstract
Precise understanding of complex physical mechanisms of mesoscale
process require high resolution observations of temperature, moisture,
wind, precipitation, clouds. Using all collocated observations of
microwave radiometer, wind profilers, electric field mill, weather
radars over South-East India an observational analysis is conducted for
the first time. Analysis suggests that these systems developed in warm,
moist environment associated with large-scale low-level convergence.
Passage of system is accompanied by convective regions with intense
upward motion and towers extending up to higher levels indicating
developing phase and presence of upward/downward motion comprising of
heavy precipitation representing mature phase of the system followed by
stratiform regions with prominent downdraft motion and less
precipitation related to decay phase. Large (small) values of
reflectivity and cloud liquid water values represent presence of deep
(shallow)convective (stratiform) regions. Cloud to Ground (CG) lightning
activity associated with storm electrification processes showed the
existence of both +CG and –CG flashes in convective and dominant –CG
in stratiform regions. Presence of different sized cloud liquid
hydrometers in convective regions resulted in bipolar nature due to
their collisions however in stratiform regions their distribution is
mostly uniform and resulted in single polarity. Combination of different
observations has provided the unique opportunity to examine
interrelations of different physical mechanisms in storm environment.
Inspection of reflectivity, CG lightning and cloud liquid water
measurements have demonstrated the relationship of lightning mechanism
with storm dynamics and cloud microphysics. Combined investigation of
temperature, moisture and wind measurements have given considerable
insight of thetae ridge formations resulting from thermal and moisture
advections. Isentropic upgliding and downgliding facilitated the unique
way to visualize the vertical transport of temperature and moisture
through ascent and descent of air parcel. Blend of observations
presented considerable insight of synoptic and complex mesoscale
processes and their mutual interactions in the storm environment and
provided encouraging results in explaining MCS structure.