The program aims for understanding the water vapour, clouds, precipitation, energy balance and associated thermo-dynamical and feedback processes by using the remote sensing techniques. The remote sensing techniques make use of a sensors that can take the measurement of the objects or areas from a distance without coming into physical contact with the observed objects. Example of remote sensors are radar, lidar, satellite etc.
Radar is an acronym for RAdio Detection And Ranging. IITM has two mobile polarimetric radars operating at X-band (~9.53 GHz) and Ka-band (~35.23 GHz). Both are scanning radars. The polarization capability of radar gives better estimation of rainfall as compared to conventional radar systems. In addition, the shape and size of the hydrometeors can also be estimated.
The Western Ghats (WGs) located parallel to the west coast of India receives a huge amount of rainfall during the Indian summer monsoon (ISM) in which topography plays a huge role in it. To understand the dynamics and microphysics of monsoon precipitating clouds over the WGs, a High Altitude Cloud Physics Laboratory (HACPL) has been setup at Mahabaleshwar (17.92 oN, 73.6 oE, ~1.4 km AMSL) in 2012. The HACPL is a natural laboratory to understand the fundamental properties of clouds, as during the monsoon, the clouds can be at the surface level and can be examined with ground based monitoring system. To supplement HACPL in-situ measurements, the IITM’s, ground based, X- and Ka-band radars are deployed at Mandhardev (18.04 oN, 73.87 oE, ~1.3 km AMSL), hills of the Western Ghats. Both radar operates in volume of plane position indicator (PPI) and range height indicator (RHI) mode and are vital instruments to understand the 3-D cloud structures along with the dynamics and microphysics of monsoon precipitating clouds over the WGs. We also have interest to validate the numerical models by comparing with radar derived products.
The space based remote sensing payloads on satellites can an unique platform for monitoring the Earth’s atmosphere. This group focuses to use satellite data (e.g., A-Train, COSMIC, GPM, INSAT-3D, ISCCP, KALPANA, MODIS, SMMR-SSM/I, VHRR, TRMM, etc) to understand the spatial characteristics of the water vapour, clouds, precipitation, thermodynamics, tropical tropopause and associated dynamics. The dataset provide climatologies of the three-dimensional distribution of clouds and precipitation, their characteristics, their variabilities at various time and spatial scales and impact on atmospheric energetics. Also, utilisation of multi-satellite data for teleconnection studies of polar, mid and tropical varibailities in understanding the large-scale dynamical effects of clouds- and aerosol-precipitation interactions over the Asian domain, in particular, over India.
Radar derived Meoscale Kinematics in terms of divergence profiles
Single Doppler analysis techniques known as velocity azimuth display (VAD) and volume velocity processing (VVP) are used to analyze kinematics of mesoscale flow such as horizontal wind and divergence using X-band Doppler weather radar observations, for selected cases of convective, stratiform, and shallow cloud systems near tropical Indian sites Pune (18.58°N, 73.92°E, above sea level (asl) 560 m) and Mandhardev (18.51°N, 73.85°E, asl 1297 m). The vertical profiles of horizontal wind estimated from radar VVP/VAD methods agree well with GPS radiosonde profiles, with the low-level jet at about 1.5 km during monsoon season well depicted in both. The vertical structure and temporal variability of divergence and reflectivity profiles are indicative of the dynamical and microphysical characteristics of shallow convective, deep convective, and stratiform cloud systems. In shallow convective systems, vertical development of reflectivity profiles is limited below 5 km. In deep convective systems, reflectivity values as large as 55 dBZ were observed above freezing level. The stratiform system shows the presence of a reflectivity bright band (~35 dBZ) near the melting level. The diagnosed vertical profiles of divergence in convective and stratiform systems are distinct. In shallow convective conditions, convergence was seen below 4 km with divergence above. Low-level convergence and upper level divergence are observed in deep convective profiles, while stratiform precipitation has midlevel convergence present between lower level and upper level divergence. The divergence profiles in stratiform precipitation exhibit intense shallow layers of “melting convergence” at 0°C level, near 4.5 km altitude, with a steep gradient on the both sides of the peak. The level of nondivergence in stratiform situations is lower than that in convective situations. These observed vertical structures of divergence are largely indicative of latent heating profiles in the atmosphere, an important ingredient of monsoon dynamics. [Deshpande S.M., Dhangar N., Das Subroto Kumar, Kalapureddy M.C.R., Chakravarty K., Sonbawne S., Konwar M., Mesoscale kinematics derived from X-band Doppler radar observations of convective versus stratiform precipitation and comparison with GPS radiosonde profiles, Journal of Geophysical Research, 120, November 2015, 11536–11551]
Project: Physics and Dynamics of Tropical Clouds
Project Director: Dr. G. Pandithurai, Scientist-F,
Sub-project: Radar & Satellite Meteorology
Dr. G. Pandithurai
Scientist-F & Project Director of Radar & Satellite Meteorology
Atmospheric Aerosol Measurements
Phone No - +91-(0)20-25904251
Dr. K. Madhuchandra Reddy
Remote sensing in Atmosphere, Cloud & Precipitation studies
Phone No - +91-(0)20-25904482
Dr. Sachin M. Deshpande
Phone No - +91-(0)20-25904234
Dr. Kaustav Chakravarty
Doppler Weather Radar Meteorology
Phone No - +91-(0)20-25904481
Dr. Subrata Kumar Das
Laser Remote Sensing, Radar and Satellite Meteorology techniques
Phone No - +91-(0)20-25904480
Phone No - +91-(0)20-25904225
Dr. (Smt.) Amita Prabhu
Monsoon variability and predictability, Satellite Meteorology
Phone No - +91-(0)20-25904240
Shri Ambuj Jha
Dr. U. V. Murali Krishna
Shri Prasad M Kalekar
Shri Hari Krishna Devisetty