Further examination of the anomaly in the radiosonde data of Ahmedabad

Abstract

In the preceding paper attention was drawn to systematic errors in the radiosonde data of Ahmedabad leading to serious anomalies in the pressure-wind relationship in the Bombay-Ahmedabad-Jodhpur sectors. Since then we have examined the monthly mean aerological data of the three stations for the 18-year period 1965-1982. The study has revealed that anomalies of a systematic nature in the radiosonde data of Ahmedabad set in from about the end of 1976 and have persisted unnoticed Since then. It IS shown that throughout the year, the upper tropospheric temperatures over Ahmedabad as evaluated from the soundings are higher than those of Bombay and Jodhpur which contradicts climatology.

The possibility that the observed temperature anomaly over Ahmedabad may be caused by heat emission from the local thermal power station has been examined by calculations of plume rise of the emissions from the stacks at the power station. It is, shown that emissions cannot have any noticeable effect on the temperatures above 500 metres. It is, therefore, concluded that the observed anomalous temperatures have no physical reality