The Linkage Between Solar Insolation and Dust in the Major World Deserts

Abstract

The annual link between the solar insolation, the surface temperature, and the dust load in the atmosphere as estimated by the TOMS Aerosol Index was compared in five major sandy deserts around the globe. A high correlation was found between the insolation and the dust in all deserts, while the correlation of dust with temperature was lower. The peaks of the insolation and the dust occurred almost simultaneously on the same date in three out of the five deserts i.e. Sahara, S.W. North American, Atacama. In the other two deserts i.e., Australian, Taklimakan, the peak of the dust occurs earlier in the year. The temperature peaks occur on a later date in all the deserts. Our conclusion is, that in the deserts of the world the radiation is the major cause of the total dust loading. Alpert et al. 2006 (1) found that the total amount of dust in the atmosphere is highly correlated with the solar insolation over the Saharan desert. Moreover, the annual maximum is reached almost on the same day, while the maximum temperature occurs a month later. This high match exists in the very great expanse of the Sahara, while in smaller areas (like the three distinct parts of the Sahara that were examined), other variables, like the local topography, the synoptic situation, etc., appear to weaken the link between dust and insolation, thus lowering the correlation. The theoretical foundation for this high correlation was discussed in detail in that paper and are summarized in chapter 2 of this paper. In this manuscript, we compare the annual link between dust, solar insolation, and the surface temperature in the Sahara and four other major sandy deserts in the world. The four other deserts examined are: the sandy part of the Australian desert, the Arizona and Sonora deserts in the Southwestern U.S and Mexico, the Taklimakan Desert in China, and the Atacama Desert in Chile. We show that in all these deserts the role of solar insolation concerning dust loading is very important, even dominant. This, in spite of the smaller areas of these deserts when compared with the Sahara, as well as their less favorable environment, such as more rugged topography, and stronger and more erratic synoptic systems. One potential application of the present findings may be the direct incorporation of the solar insolation in dust prediction models. The strong correlation of radiation and dust load dates in the major deserts around the world can further improve these models. Better models for short and long term forecasting of dust events can aid in dealing with