By
Ashok Jaswal, India Meteorological Department, On May 21, 2011
Abstract
This study analyses near-surface wind speed changes in India during 1961 to 2008. Consisting of monthly wind speed data of 171 stations, the results show that most of the stations in India have experienced significant weakening of wind speed , both at monthly and annual timescales. All-India averaged annual mean wind speed has decreased from 9.7 kmph in 1961 to 5.0 kmph in 2008 resulting in a 49% decline. Averaged rate of decrease in annual mean wind speed is -0.88 kmph/decade. The largest rate of decline is in June (-1.33 kmph per decade) and the smallest is in October (-0.60 kmph per decade). Spatially, large declines are found in western India, south peninsula and the coastal areas while central, southeast and northeast India have the lesser change in wind speed . Significant weakening of wind speed has occurred primarily in regions along Gujarat, Maharashtra, Tamil Nadu, north Karnataka, and coastal Orissa and West Bengal which also have higher annual mean wind speed . Annual mean wind speeds exceeding 15 kmph are observed only over Gujarat and south Tamil Nadu. Some parts of Rajasthan, west Madhya Pradesh, Maharashtra, north Karnataka and adjoining Andhra Pradesh and the coastal belts experience wind speeds of 10-15 kmph. Stations having annual mean wind speed exceeding 10 kmph are rare in northern India.
The study evaluates climatology of winds and its long-term trends over India where wind power can be profitably utilised. The prominent regions are in Gujarat and adjoining Madhya Pradesh, south Rajasthan, north Maharashtra, north Karnataka, south Tamil Nadu, coastal Andhra Pradesh and along the west coast from Gujarat to Goa and along the east coast from Kolkata to Nagapatinam.
