The role of terrestrial radiation in the generation of zonal and eddy available potential energy

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Abstract
Time averaged estimates of the generation of atmospheric zonal and eddy available potential energy by infrared radiation are obtained from 198 radiometersonde flights made at thirteen stations located in the eastern half of the United States and Caribbean Sea area. From the temperature and net radiation data the vertical profiles of temperature and atmospheric cooling are individually estimated by “least squares” approximating polynomials. A polynomial integration technique is developed to obtain the time averaged covariance of the cooling and temperature profiles for each of seven atmospheric layers. The time averaged estimates for each of the seven atmospheric layers are divided into transient, stationary eddy, and stationary zonal components. The results indicate that all are sinks of available potential energy with the estimates for the transient component being — 0.13 watts/m2, the stationary eddy being —0.08 watts/m2, and the stationary zonal being — 1.92 watts/m2. An analysis of the daily values indicates that the transient generation varies considerably from day to day and at times attains large positive or negative values. The range of the transient generation estimates is slightly larger than the range of frictional dissipation estimates within the planetary boundary layer for light and moderate winds. There are pronounced vertical variations in the generation estimates with the extreme values, both positive and negative, occurring in the lower troposphere. This is undoubtedly the result of the varying distribution of cloudiness and water vapor. Because of the large daily variations as well as vertical variations, it appears that additional intensive studies of the generation for local disturbances should be undertaken. The implication of a positive infrared generation by the net heating component on a pressure surface is discussed. DOI: 10.1111/j.2153-3490.1967.tb01506.x