Data on surface ozone concentration compiled for a 10-year period from 1990 to 1999 for Pune and Delhi are analyzed in terms of its frequency distribution, annual trend, diurnal variation and its relation with various meteorological and chemical parameters. It is found that the surface ozone concentration range showing highest frequency of occurrence at Pune is 0–5 ppb during winter and post-monsoon seasons and 15–20 ppb and 5–10 ppb during summer and monsoon seasons, respectively. It is 0–5 ppb at Delhi during all the seasons.

India Meteorological Department has implemented district level medium range rainfall forecast system applying multimodel ensemble technique, making use of model outputs of state-of-the-art global models from the five leading global NWP centres.

Time series analysis of Aerosol Optical Depth (AOD) derived from NOAA-AVHRR data during the period 1996–1999 and the MODIS data during 2000–2009 over the Arabian Sea revealed a systematic biennial variability in the high AOD during summer months. The variability is more prominent over the northern and central parts of the Arabian Sea and became less significant towards southern latitudes. The possible mechanisms for these are examined by estimating the source strength over coastal Arabia and AOD flow rate through the western boundary of the Arabian Sea.