Air Temperature, Water Bodies and ContinentalityAir temperature is greatly affected by the location of a place relative to a large body of water. The impact of continental location on weather and climate characteristics of a place is called "continentality". Air temperature near or over bodies of water is much different from that over land due to differences in the way water and land heat and cool. Properties that affect water temperature are:
Water is a transparent medium and land is opaque. Water allows light to penetrate to depth, leaving the surface layers cooler than they would be if the surface was opaque. A cooler water surface results in cooler air temperatures above. When solar radiation strikes land, the energy is absorbed in a thin layer that heats relatively rapidly. Likewise, it readily gives up its heat to the atmosphere. When radiant energy is absorbed by land, most of the net radiation is used for sensible heat transfer or ground heat transfer, only small amounts are used for latent heat transfer. As sensible heat transfer into the air is the dominant heat transfer, air temperatures increase over the land. Over water, much of the net radiation is used for evaporation. With little energy used for sensible heat transfer, air over water remains cooler than that over land. |
