Accurate prediction of movement and intensity of tropical cyclone is still most challenging problem in numerical weather prediction. The positive progress in this field can be achieved by providing network of observations in the storm region and best representation of atmospheric physical processes in the model. In the present study later part was attempted to investigate the sensitivity of movement and intensity of the severe cyclonic storm AILA to different physical processes in the Weather Research and Forecasting model. Three sets of experiments were conducted for convection, microphysics (MP) and planetary boundary layer (PBL) processes. Model-simulated fields like minimum central surface pressure, maximum surface wind, track and vector displacement error are considered to test the sensitivity. The results indicate that the movement of the system is more sensitive to the cumulus physics and the intensity of the cyclone is sensitive to both PBL and cumulus physics. The combination of Betts Miller Janjic (BMJ) for convection, Yonsei University (YSU) for PBL and Purdue Lin (LIN) for microphysics is found to perform better than other combination schemes. The horizontal and vertical features of the system along with its special features like complete northward movement of the system throughout the travel period and the consistent cyclonic storm intensity until 15 hrs after the landfall could be well simulated by the model.

Ground-based microwave radiometers are getting great attention in recent years due to their capability to profile the temperature and humidity at high temporal and vertical resolution in the lower troposphere. The process of retrieving these parameters from the measurements of radiometric brightness temperature (T B) includes the inversion algorithm, which uses the background information from a forward model. In the present study, an algorithm development and evaluation of this forward model for a ground-based microwave radiometer, being developed by Society for Applied Microwave Electronics Engineering and Research (SAMEER) of India, is presented. Initially, the analysis of absorption coefficient and weighting function at different frequencies was made to select the channels. Further the range of variation of T B for these selected channels for the year 2011, over the two stations Mumbai and Delhi is discussed. Finally the comparison between forward-model simulated T B s and radiometer measured T B s at Mahabaleshwar (73.66 • E and 17.93 • N) is done to evaluate the model. There is good agreement between model simulations and radiometer observations, which suggests that these forward model simulations can be used as background for inversion models for retrieving the temperature and humidity profiles.

The Indian northeast monsoon is inherently chaotic in nature as the rainfall realised in the peninsular India depends substantially on the formation and movement of low-pressure systems in central and southwest Bay of Bengal and on the convective activity which is mainly due to the moist north-easterlies from Bay of Bengal. The objective of this study is to analyse the performance of the PSU-NCAR Mesoscale Model Version 5 (MM5), for northeast monsoon 2008 that includes tropical cyclones -Rashmi, Khai-Muk and Nisha and convective events over Sriharikota region, the rocket launch centre. The impact of objective analysis system using radiosonde observations, surface observations and Kalpana-1 satellite derived Atmospheric Motion Wind Vectors (AMV) is also studied. The performance of the model is analysed by comparing the predicted parameters like mean sea level pressure (MSLP), intensity, track and rainfall with the observations. The results show that the model simulations could capture MSLP and intensity of all the cyclones reasonably well. The dependence of the movement of the system on the environmental flow is clearly observed in all the three cases. The vector displacement error and percentage of improvement is calculated to study the impact of objective data analysis on the movement and intensity of the cyclone.

Convection has a significant role in maintaining the atmospheric dynamics and thermodynamics; particularly in the tropical regions, it can often lead to the formation of clouds and precipitation, release of latent heat, etc. Microwave radiometers (MWRs) have evolved as a powerful tool for monitoring the genesis and evolution of the convection over a site. Ground-based MWRs are installed at the Satish Dhawan Space Centre SHAR, (SDSC SHAR) Sriharikota (13.72°N; 80.18°E) located over south coastal Andhra Pradesh, the southeast coast of India in 2014. MWR provides high temporal resolution vertical profiles of temperature, vapour density and liquid column measurements. The mean profiles of temperature and vapour density of upper-air ascents of GPS radiosonde and microwave radiometer (MWR) are compared for the same location. After the middle of October, the rainfall pattern over south peninsular India and in particular Tamil Nadu and south coastal Andhra Pradesh is due to the arrival of the northeasterly/easterly winds. The aim of the present study is to use MWR products for the northeast monsoon (NEM) onset study. In addition to the European Centre for Medium-Range Weather Forecasts (ECMWF) and operational WRF models, reanalysis data products were also used for the study. The association between the temporal evaluation of thermodynamic profiles and NEM onset has been tested for 3 years. The present results suggest that during the period of NEM onset, 3-5 days early signatures can be observed by MWR.