Abstract

Abstract The analyses annual of solar angel altitude in surface slopes of Iran The solar altitude angel is one of the factors that effect on the amount of the energy that received the surface of the earth from sun, that itself depend on the latitude, amount of the earth's slopes, direction of the earth's slopes, the time of day and years of season. There are many formulas for estimation of the solar altitude angel in the slopes, that here attempts to consider these factors which by the use one of the experimental formulas, daily mien of the solar altitude angel consider at during the year in the slopes of 0 to 90 degrees, in 16 major and meaner direction and in Iran's latitude (from 25 to 40 north degrees). For estimation of the relationship between amount of the slopes angel with the solar altitude angel can use from calculated digits. We can mead several analyses from this relationships, including we can determinate the slopes of the surface of the earth that the solar altitude angle have more or less tendency. Keywords: solar altitude, angel, slope's surface, direction, latitude, time.