利用GCM模式对全球雷电活动的模拟分析

将修正的参数化方案嵌套入美国马里兰大学海-陆-气研究中心的全球大气环流谱模式(COLAGCM),建立了可用于全球雷电活动模拟与估测的模式系统.通过对模式输出与实况资料的对比,检验其气候模拟性能.虽然模式的分辨率较低但经过较长时间积分,仍可再现实况资料的主要特征.性能良好,计算稳定,且因时间步长较大可大大节省机时.耦合模式系统经长时间的积分后,模拟的多年平均的全球雷电频次时空分布及变化与观测分析较一致.全球范围内每秒钟平均有79次的雷电发生,陆海比为12.2.多发生在北半球夏季且具明显的季节变化特征.

Simulation Experiments of Global Lightning Distributions by a Coupled GCM

A general circulation model (GCM) system nested into the parameterizations that relate the depth of convective clouds to lightning frequencies is established and used to study model global lightning distributions and frequencies. The gridded data from NCEP are used to verify the perform- ance of the above model system. The verification shows that the system is stably integrated with good performance. The model can globally simulate main circulation at high altitude area and land surface pressure, so can be used to study climate change and variation. The lighting--cloud height parameterizations are nested into GCM, the preliminary simulations show that the nested system can reproduce the main spatial and temporal characteristics and changes of global lightning. The annualy mean global lightning frequency in the model is 79 flashes per second, with a land--ocean ratio of 12.2, and the maximum global lightning activities occur during the Northern Hemisphere summer. The model's lightning climatology is compared with available observations, and statistical tests show there is a good agreement.