The Study of Spatial Distribution of Precipitation and Stable Isotope Content in Mountainous Watershed of MidHimalaya,Northern India from Short Term Records of Monsoon Period

Abstract

Mountain microclimate is governed by the interplay of insolation, wind, air temperature and topographic dispositions. The lack of appropriate scientific baseline data in all across Indian Himalaya is impairing effective planning process as implementation are being carried out at village clusters at a local scale. This study investigates spatial rainfall variability during the four crucial months of monsoon in a microwatershed (<10km2 ) that is part of large watershed in southern slopes of Lesser Himalaya. To understand the altitudinal variability in terms of daily rain and rainfall isotope variability, samples were collected along transect of 5000m within an altitudinal variability of 700m. The isotopic lapse rate (altitude effect) deciphered at a local scale that has immense role in identifying the recharge areas of local water resources. Monthly surface air temperature is also being investigated along the same transect as it has influence on the isotopic lapse rate. The observed topographical lapse rate is within the range of lapse rate reported for monsoon period from Himalayan region. The study also looks into the various climatological aspect of synoptic and local circulation controlled by orography.