冰晶增长对热量收支的影响

使用二维云分辨模式研究冰晶增长过程(云水到冰晶的冻结增长和通过水汽凝华冰晶到雪的增长)对热量收支的影响。采用4种冰晶增长参数化方案模拟了热带到中纬度地区的4个降水个例。研究发现:(1)高冰核浓度的ZENG方案和SHEN方案引起对流层中上层辐射加热增多,这与它们模拟的冰晶在对流层中上层增多有关。(2)高冰核浓度的ZENG方案导致模拟区域—平均的局地温度变化在对流层上层出现异常减小值,这与它在热带个例中导致垂直热量通量辐合减少和在中纬度个例中导致潜热加热减少有关。(3)尽管高冰核浓度的ZENG方案引起质量加权平均的辐射加热增多,但是它在热带个例中引起地表感热通量减少和在中纬度个例中引起潜热加热减少,最终导致4种参数化方案计算的模拟区域—质量加权平均的局地温度变化基本一致。

The impacts of ice crystal growth on heat budget

A two-dimensional cloud-resolving model was used to study the impacts of ice crystal growth (the depositional growth of cloud ice from cloud water and the depositional growth of snow from cloud ice) on heat budget. Four precipitation events from the tropics to mid-latitudes were simulated with four sets of parameterization scheme for the growth of ice crystal. The main results include the followings:(1) Zeng''s scheme with a high ice nuclei concentration and Shen''s scheme cause the increase of the radiation heating in upper-middle troposphere, which is associated with the increased quantity of simulated ice crystals in upper-middle troposphere. (2) Zeng''s scheme with a high ice nuclei concentration leads to an abnormal reduction in domain-mean local temperature change in the upper troposphere, which results from the reductions in the convergence of vertical heat flux over the tropics and the latent heating over mid-latitudes. (3) Although Zeng''s scheme with a high ice nuclei concentration increases the domain-mean mass-weighted radiation heating, it decreases the surface sensible heat flux over the tropics and the latent heating over mid-latitudes. Thus, the four parameterization schemes generate similar domain-mean mass-weighted local temperature changes.