The Computation of Equivalent Potential Temperature

Abstract

A simplified procedure is described for computation of equivalent potential temperature which remains valid in situations such as in the tropics where a term which is omitted in the derivation of the conventional formula can lead to an error of several degrees absolute. The procedure involves new empirical formulas which are introduced for the saturated vapor pressure of water, the lifting condensation level temperature and the equivalent potential temperature. Errors are estimated for each of these, and results are compared with those obtained by the similar, but more complicated procedures of Betts and Dugan (1973) and Simpson (1978). Abstract A simplified procedure is described for computation of equivalent potential temperature which remains valid in situations such as in the tropics where a term which is omitted in the derivation of the conventional formula can lead to an error of several degrees absolute. The procedure involves new empirical formulas which are introduced for the saturated vapor pressure of water, the lifting condensation level temperature and the equivalent potential temperature. Errors are estimated for each of these, and results are compared with those obtained by the similar, but more complicated procedures of Betts and Dugan (1973) and Simpson (1978).