Willard, New Mexico solar irrigation site indicated that troughshaped solar thermal collectors arranged in rows may have increased turbulence and wind erosion compared to adjacent open areas during periods of high wind velocity. Temperature and Heat Flux The effect of wind deflection by solar collectors on temperature may be an increase in daytime air and soil temperatures, based on shelter studies of sites leeward of windbreaks (Jensen 1954, Aslyng 1958, Rosenberg 1966a, King 1970, Hanson and Ravzi 1977). Warmer temperatures due to wind deflection are assumed to be the norm due to a decrease in turbulent exchange resulting in more intense vertical temperature gradients (Rosenberg 1974). An exception is the findings of Stepanov (1971), who found that shelterbelts reduce surface temperatures of sandy desert soils. Night temperatures apparently are not as consistently affected as daytime temperatures. Although there are studies which have observed warmer night temperatures in sheltered areas (Rosenberg 1966a, Tuller 1973), Rosenberg (1974) concludes in a review of shelter studies that night temperatures will be lower in shelter due to more intense nocturnal air inversions. Since these inversions are common in the southwestern deserts, reduction of nocturnal air temperature due to wind deflection could be substantial. Predictions of temperature changes under solar collectors tend to agree with the shelter studies in predicting increased daytime air temperatures under heliostats (Black and Veatch 1977) and photovoltaic arrays (ERDA 1977a). However, soil temperatures are predicted to be unaffected (Black and Veatch 1977), and nocturnal temperature will either be unaffected (ERDA 1977b) or slightly warmer (Black and Veatch 1977). Assumed decreases in turbulance will be a factor here, as various configurations of collectors and arrays of collectors will influence degree of turbulent exchange within the array field. Regardless of whether temperatures will be warmer or cooler, the absolute changes of temperature in collector fields should be slight due to wind deflection. If, however, daytime temperatures are warmer and nighttime temp-
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