Seasonal variability in evaporation and bright sunshine in semi-arid region.

摘要

Long-term seasonal variation and trends in evaporation and bright sunshine hours data for the period 1990-2006 of Jhansi, Uttar Pradesh, India were studied to quantify possible changes on seasonal basis for crop planning over the region. For seasonal variations, three distinct crop growth periods, viz., kharif (26-41 standard meteorological weeks (SMWs)), rabi (42-15 SMW), and summer (16-25 SMW) were considered. Evaporation data revealed that the climatological normal for annual, kharif, rabi and summer season were 5.5, 4.8, 3.6 and 11.1 mm/day, respectively. No significant and systematic trend was observed in annual and rabi seasons. The climatological normals of bright sunshine for annual, kharif, rabi and summer season were 7.8, 5.9, 8.7 and 8.9 h/day, respectively. A decreasing trend was observed in annual and summer seasons.