A nowcasting technique has been proposed to estimate the impending rain accumulation using ground-based radiometric measurements at Kolkata (22.65°N, 88.45°E), a tropical location. It has been observed that the normalized variation of brightness temperature (BT) at 31 GHz along with the standard deviation of BT at 22 GHz and instability indices, namely, lifting index, have shown definite changes before rain events. A combination of these three parameters can be effective in predicting rain events both qualitatively and quantitatively. Accordingly, a prediction model is developed and tested on several intense rain events during the period 2014–2015. The model is found to perform reasonably well in predicting intense rain about 70–75 min in advance with an efficiency of 80%.

Prediction of Rain Occurrence and Accumulation Using Multifrequency Radiometric Observations

Tropopause height characteristics associated with ozone and stratospheric moistening during intense convective activity over Indian sub-continent

Rain attenuation is an important aspect of signal propagation mainly above 10 GHz frequency. It has also been found that the rain rate and attenuation profiles along the vertical and slant propagation path, especially at a higher rain rates and at tropical location. In this study, a simple approach is taken to study rain attenuation at various frequencies from propagation data and ground based radar measurements at Kolkata, INDIA. The ITU-R Model and the SAM Model has been utilized to provide an estimate of the slant rain rate and total attenuation from the vertical rain rate profiles.

Bidisha Nandy

Papers

Rain attenuation over earth space path from radar and propagation measurements at tropical location