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Northwest India; winter precipitation; western disturbances; rabi crops; precipitation variability; precipitation epochs.

Northwestern parts of India receive considerable amount of precipitation during the winter months of December–March. Although, it is only about 15% of the annual precipitation, the precipitation is very important for rabi crops and to maintain the glaciers extend in the Himalaya, which melt and supply water to the rivers during other seasons. The precipitation is mainly associated with the sequence of synoptic systems known as ‘western disturbances’. The precipitation has considerable spatial and temporal variability, with maximum precipitation occurring particularly over northern hilly regions, with decreasing influence southwards. The spatially coherent winter precipitation series has been prepared for the largest possible area comprising nine meteorological subdivisions of northwest India, which constitute about 32% of the total area of the country, having similar precipitation characteristics. The precipitation series has been statistically analysed to understand its characteristics and variability. The seasonal precipitation series is found to be homogeneous, Gaussian (normal) distributed and free from persistence. The precipitation variability has increased during the most recent three decades with more excess and deficient years.

R K Yadav¹ K Rupa Kumar² M Rajeevan³

1. Indian Institute of Tropical Meteorology, Pune, India.
2. World Meteorological Organization, Geneva, Switzerland.
3. National Atmospheric Research Laboratory, Tirupati, India.

Published

June 2012

Manuscript received

29 April 2011

Manuscript revised

26 December 2011

Accepted

26 December 2011