Two-dimensional numerical experiments of atmospheric convection with condensation of the major component under early Mars condition

本文建立了一个二维云解析模式，在考虑火星早期温暖大气的简化热条件下，研究了与主要成分凝结有关的对流行为，在不允许过饱和的情况下，得到了准定常的流场和云的分布。凝结层以下发展出胞状对流结构，凝结层以上产生重力波并传播。云是由重力波引起的垂直运动形成的。当允许过饱和时，对流的行为取决于凝结核数混合比的大小：当凝结核数混合比较大时，对流解为准定常解，而当凝结核数混合比较小时，对流解为准周期解.在后一种情况下，上升气流只通过有限深度的凝结层发展。

We have developed a two-dimensional cloud resolving model and investigate the behavior of convection associated with the condensation of the major constituent in a simplified thermal condition considering the warm early Mars atmosphere.When super saturation is not permitted, quasi steady distributions of flow field and cloud are obtained. A cellular convection structure develops below the condensation level, and gravity wave is generated and propagates above the condensation level. Cloud is formed by vertical motion associated with the gravity wave. When super saturation is permitted, the behavior of convection depends on the value of number mixing ratio of condensation nuclei: quasi-steady solution is obtained for relatively large number mixing ratio of condensation nuclei, whereas solution with quasi-periodic temporal variation is obtained for relatively small number mixing ratio. In the latter case, the updrafts develop through only a limited depth of the condensation layer.