Recent biennial variability of meteorological features in the Eastern Highland Himalayas

Abstract

With meteorological data from high altitude surface stations and gridded dataset from NCEP/NCAR Reanalysis, a biennial oscillation over the Eastern Highland Himalayas from 1980 to 1998 is described. This variability concerns air temperature, precipitation, geopotential and wind speed. Evidence is given on the connections between local data and large-scale circulation patterns. The most remarkable oscillating features are found during winter and, in general, the signals are particularly marked on the southern slope of the Himalayan Range. A possible mechanism is explained in terms of a periodicity in surface heat and moisture fluxes. Finally, the peculiarity of the region as a climatic change observatory is underlined.