Tendency Computations with a Continuous Two-Parametric Atmospheric Model

In a case of strong development the tendencies at the 500 and 1000 mb surfaces are computed with a two parametric model. It is possible to take the thermal structure of the atmosphere into account in a crude manner by expressing the vertical temperature distribution as a function of the deviation of the 1,000–500 mb thickness from a standard value. The height of the 500 mb surface and the 1,000–500 mb thickness are used as variables. The tendencies are computed for two maps 12 hrs apart, the intermediate tendencies interpolated for every 2 hrs and the 12 hr change of the 1000 and 500 mb surfaces are then computed. The tendencies computed represent an improvement over those computed with the barotropic model, but the 12 hr changes are still only about 2/3 of the observed changes.