ABSTRACT
Out of all meteorological parameters, water vapor and nonprecipitable liquid water, along with ambient temperature, are found to be the most important parameters to control the thermodynamic balance, photochemistry of the atmosphere, sun-weather relationship, and biosphere. Measurements of the vertical and horizontal distribution of water vapor, as well as its temporal variation, are essential for probing into the mysteries of several atmospheric effects. A sizable literature has focused on the complex relationship between water vapor variability and deep convection in the tropics (Sherwood et al., 2009). Unlike higher latitudes, rotational dynamical constraints are weak and precipitation-induced heating perturbations are rapidly communicated over great distances. Water vapor, on the other hand, is highly variable in space and time; its spatial distribution depends on much slower advection processes above the boundary layer and on deep convection itself. Furthermore, deep convection, through vertical transport of water vapor and evaporation of cloud droplets and hydrometeors, serves as the free tropospheric water vapor source. And deep convection is itself sensitive to the free tropospheric humidity distribution through local moistening of the environment, which favors further deep convection, a positive feedback (David et al., 2011). In this context, the ground-based microwave radiometric sensing appears to be one of the suitable solutions for continuous monitoring of ambient integrated atmospheric water vapor. Radiometric data have been extensively used by several investigators (Westwater, 1972; Grody, 1976; Grody et al., 1980; Westwater and Guiraud, 1980; Pandey et al., 1984; Janssen, 1985; Cimini et al., 2007) to determine the water vapor budget.
