Mesoscale Temperature Changes in the Supersonic Transport Climb Region

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  • 1 Air Force Cambridge Research Laboratories, Bedford, Mass.
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Abstract

Supersonic transport (SST) fuel consumption is very sensitive to ambient temperatures in the region of climb from 25,000 to 52,000 ft within 200 n mi and 20 min of takeoff. It has been suggested in the literature that extensive sounding networks may be required to provide adequate temperature forecasts for SST operations.

The thermal wind relation implies that the mean temperature in this deep layer will not change rapidly in space or time and that wind shears can be used as predictors of the changes. An empirical study using the Project Stormy Spring mesoscale rawinsonde network data confirms the thermal wind implication that these mesoscale temperature changes are small. Only 6-hr soundings at a single site near the airport are required for reasonably efficient SST operation. However, predictions based on wind shear explain only about 20% of the variance of the observed temperature changes.

Abstract

Supersonic transport (SST) fuel consumption is very sensitive to ambient temperatures in the region of climb from 25,000 to 52,000 ft within 200 n mi and 20 min of takeoff. It has been suggested in the literature that extensive sounding networks may be required to provide adequate temperature forecasts for SST operations.

The thermal wind relation implies that the mean temperature in this deep layer will not change rapidly in space or time and that wind shears can be used as predictors of the changes. An empirical study using the Project Stormy Spring mesoscale rawinsonde network data confirms the thermal wind implication that these mesoscale temperature changes are small. Only 6-hr soundings at a single site near the airport are required for reasonably efficient SST operation. However, predictions based on wind shear explain only about 20% of the variance of the observed temperature changes.

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