Climate, Snow Cover, 

 Microclimate, and Hydrology 



S. L. Dingman, R. G. Barry, G. Weller, 



C. Benson, E. F. LeDrew, and C. W. Goodwin 



INTRODUCTION 



The environmental conditions within a few meters above or below 

 the ground surface constitute the microclimate of a region, and it is to 

 these conditions that most terrestrial organisms must adapt. The micro- 

 climate is characterized by the radiation, temperature, and moisture re- 

 gimes of the near-surface atmospheric and soil layers. These regimes are 

 determined largely by the regional climate, as modified by local top- 

 ography and by the vegetation cover. 



Quantitatively, the microclimate is described by the energy and 

 water balances at the surface. These balances are complexly related. The 

 net radiation input to the land surface provides the energy that is utilized 

 in surface physical and biological processes. The energy balance express- 

 es how this energy is partitioned, and the water balance is determined by 

 the energy balance. At the same time, the water balance influences the 

 magnitude of the energy balance components through latent heat ex- 

 changes and through the effects of snow on surface conditions. 



For comparison, descriptions of radiation, energy and water bal- 

 ances at other arctic sites can be found in Ohmura (1972), Weller and 

 Holmgren (1974a and b). Woo (1976), Ohmura and Muller (1976), 

 Stewart and Rouse (1976), Courtin and Labine (1977), Ryden (1977), 

 and LeDrew and Weller (1978). Dingman (1973) published an annotated 

 bibliography covering much of the pre-1972 literature on the water bal- 

 ance in arctic and subarctic regions. 



CLIMATE 



Climatic Setting 



Traditionally, areas where the average temperature of the warmest 

 month is below 10 °C have been identified as having a tundra climate 



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