Seas, oceans and large lakes in the warm season
Features of the annual cycle in surface air temperature in different parts of the Earth according to OA of the hydrometcentre of the Russian Federation
Seas, oceans and large lakes in the warm season accumulated in its layers a considerable amount of heat. In the winter they give him air. Therefore, the air above the water surfaces in winter is warmer than over land.
The surface of the continents in turn are heterogeneous. Forests, swamps, grasslands, fields give the air different amounts of heat. In addition, the different soil types (topsoil, sand, peat) also have a different thermal influence on the air .
Vegetation has a significant influence on air temperature. The surface of a dense vegetation cover absorbs almost all incoming radiation to it and almost is the active surface. Surrounding air during the day warms up, and up and down from this surface the temperature decreases. At night above the surface of the vegetation as a result of its radiation, the air is coldest. In vegetation cover the cooled air descends to the level of more dense foliage. In this case, the active surface is the outer surface of vegetation, and a somewhat lower level. During the day the air above the canopy is heated, and at night is cooled lower than over bare soil. This is due to the high heat capacity of the vegetation cover, as well as the fact that some radiant energy entering the plant cover, is spent in the various physical and biological processes mainly by evaporation.
In the forest the maximum and minimum air temperature observed over the canopy of trees and if the leaves are rare, a few lower crowns. Therefore, the largest amplitude is also observed above the canopy, and above and below are reduced. From numerous observations of the temperature of the air in the forest, under trees and in open field found that the average temperature in the forest is lower than in the field. Increasing nighttime lows and daytime highs lowering, forest smooths out daily fluctuations in temperature. The amplitude of the diurnal variation of air temperature in the forest about 2°C less than in the field.
The thermal regime of the city. Cities have a significant impact on air temperature. In the summer of residential buildings, various municipal buildings, pavement, etc. when heated, give its heat to the air. Therefore, the temperature of the air in the city is higher than in the surrounding area. Especially great is the difference in the evening hours when the buildings and structures, strongly heated by day, gradually give up its heat to the air. In addition, the city is almost no patches of open soil and the relatively small area of vegetation, so there is less loss of heat to evaporation. It also increases the temperature of the air in the city .