Atmospheric Absorption Ratio on Cities of Pernambuco State of Brazil
Abstract
The second satellite of the Brazilian Complete Space Mission (SCD2/MECB) was launched on October 23, 1998 and it hosts on board a solar cell experiment. The experiment permits the simultaneous inference of direct insolation and the insolation that is reflected outside of Earth (planetary albedo). The data of albedo can be grouped into periods of time (annual, seasonal or monthly) or studied for several places (latitude and longitude) during the life of the satellite. In this work, the albedo values is used with the Atmospheric transmission coefficient or clearness index (Kt), measured at four meteorological stations of Pernambuco State of Brazil to calculate the atmospheric absorption coefficient (Ka). The developed method in this work for evaluating the Ka considers that the planetary albedo is composed by two parts: the local and the non local reflectivity. Considering this original concept, a new parameter called atmospheric net ratio (called here Ra) is defined as the quotient between Ka and the net solar irradiance power that is not transmitted through the atmosphere (100%-Kt). The atmospheric net ratio defined by this way is not cloud cover dependent. For example, the values of Ra to Recife are 0.9186±0.0147 and 0.9131±0.0087 to two periods with atmospheric conditions slightly different. The data was taken during the months of January and February of 2013. The values of Ra to the four cities of this work indicate different climate and atmospheric conditions in the cities of Pernambuco State.
Keywords
Atmospheric Absorption, Solar Energy, Satellite, INPE, Pernambuco State of Brazil