ATMOSPHERIC BOUNDARY-LAYER STUDIES AT JODHPUR DURING MONTBLEX USING SODAR AND TOWER

A monostatic sodar was set up at Jodhpur, near the western end of the monsoon trough, to investigate the atmospheric boundary layer dynamics . A 30 m instrumented tower was also located close to the sodar antenn a. Data were collected from June to August during the monsoon period o f 1990, as also from July 1992 to September 1993. Thermal plumes, surf ace-based stable layers (both flat or short spiky top and tall spiky t op), elevated/multi-layers with or without undulations and dot echo st ructures were seen; however, erosion of the morning inversion layer in the form of a rising layer with growing thermal plumes under it was r arely seen, and that too only during the winter period. The observed s tructure of the stable layer with tall spikes and its depth have been found to be correlated with the intensity of the monsoon spell; the do t echoes have been found to be correlated with the approach of a monso on depression near Jodhpur; and the elevated/multilayers have been att ributed to the formation of a subsidence (shear instability).