The objectives of the Winter Fog Experiment (WIFEX) over the Indo-Gangetic Plains of India are to develop better now-casting and forecasting of winter fog on various time- and spatial scales. Maximum fog occurrence over northwest India is about 48 days (visibility <1000 m) per year, and it occurs mostly during the December–February time-period. The physical and chemical characteristics of fog, meteorological factors responsible for its genesis, sustenance, intensity and dissipation are poorly understood.

A Southern Ocean Pilot cruise covering the latitudes from 10°N to 56°S in the open Indian Ocean was car-
ried out during January–February 2004. Surface and upper air data collected during this cruise are re-
ported here. It is shown that the broad features of the atmosphere, in particular that of temperature, follow