Global Distribution of Net Radiation According to a New Formula

A new formula for estimating net radiation has been derived from records of solar radiation, humidity, and air temperature. The formula is believed to be an improvement over the previous ones which used cloudiness instead of solar radiation. The correlation coefficient between the computed and actual values is 0.97 and the standard error of estimate is 2.57 langleys/day. The limitations of the formula, such as the use of standard values of reflection coefficients, the use of surface humidity instead of total precipitable water, and the exclusion of carbon dioxide, are discussed. The formula has been applied to 386 stations for the construction of world maps for four mid-season months as well as for the year. The distributional pattern differs somewhat from the world maps prepared by Budyko. Solar radiation retained as net radiation decreases from sixty percent in the tropics to less than twenty percent in high latitudes.