摘要:本文利用中国自动站与CMORPH（Climate Prediction Center Morphing technique for the production of global precipitation estimates）融合的逐时降水量0.1°网格数据集资料挑选出一次典型的梅雨锋暴雨个例，运用WRF中小尺度模式进行模拟，对模拟得到的高分辨率结果进行Barnes滤波，最后将滤波结果代入动能和位能方程中，目的是定量地分析各个尺度能量的变化以及它们之间的相互作用对暴雨强度的影响。研究发现：模式模拟的降水过程和强度与实况较为吻合，推导的能量方程适用于这次暴雨过程。三种尺度能量之间的相互作用包含了各种跨尺度能量的相互作用。在整个暴雨过程中，跨尺度之间的斜压能量转换包括位能向动能的能量转换和动能向位能的能量转换。同尺度之间的斜压能量转换总是单向的，且量值较大，动能的强度主要靠位能向动能的能量转换来维持。斜压能量转换的多少影响着暴雨的强弱。大尺度斜压能量转换在中高层比较强，中尺度斜压能量转换在低层较强，尤以β中小尺度系统变化最为显著，β中小尺度系统扰动是影响暴雨强度的关键系统。风切变的大小影响各尺度动能之间的能量转换。温度或位温梯度的大小影响各尺度位能之间的能量转换。位能与动能之间的能量转换主要与各尺度垂直速度和温度的垂直分布有关，暖空气上升冷空气下沉是各个尺度位能向动能转换的主要过程。
关键词:梅雨锋暴雨/
WRF模式/
Barnes滤波/
动能和位能方程/
相互作用
Abstract:In this paper, the fusion data of observations collected at automatic stations in China and CMORPH (Climate Prediction Center Morphing technique for the production of global precipitation estimates) hourly precipitation at 0.1° resolution are used to identify a typical Meiyu front rainstorm, which is then simulated by WRF model. The simulation data is filtered by Barnes filtering. The energy equations are applied to analyze the filtered data for the purpose to quantitatively analyze the effects of interactions between multi-scale energy on the rainstorm intensity. The results are as follows. The simulated precipitation and its intensity are consistent with observations, which indicates that the simulation can be used in the following research. Besides, these derived energy equations can be applied to the rainstorm. The interactions between energy on the three scales involve a variety of cross scale energy interactions. During the entire rainstorm process, the baroclinic energy conversions across various scales not only include the energy conversions from available potential energy to kinetic energy, but also from kinetic energy to available potential energy. However, the baroclinic energy conversions between these scales are always unidirectional, and the value is large, that is, the strength of kinetic energy is maintained mainly by the energy transformation from the available potential energy to the kinetic energy. The baroclinic energy conversions influence the rainstorm intensity. And the baroclinic energy conversions of large scale are stronger than others in the upper and middle troposphere, while the baroclinic energy conversions of meso scale are stronger than others in the lower troposphere, especially the meso-micro-β scale. Meso-micro-β scale disturbance may be the key system that influences the intensity of rainstorm. The magnitude of wind shear affects energy conversions between different scales of kinetic energy. The magnitude of temperature or potential temperature gradient affects energy conversions between the available potential energies at various scales. The energy conversions between the available potential energy and kinetic energy are mainly related to distributions of vertical velocity and temperature of each scale. The rising of warm air and the sinking of cold air are the main processes of the conversions from available potential energy to kinetic energy at various scales.
Key words:Meiyu front rainstorm/
WRF model/
Barnes filtering/
Kinetic energy and available potential energy equation/
Interaction
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