Utilization of High-Resolution Boundary Layer Radar and Wavelet to Detect Microscale Downdraft-Updraft Combination
Utilization of High-Resolution Boundary Layer Radar and Wavelet to Detect Microscale Downdraft-Updraft Combination
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DOI：
10.2151/sola.2021-010
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发表时间：
2021-02
期刊：
影响因子：
1.9
通讯作者：
G. A. Nugroho;K. Yamaguchi;E. Nakakita;Masayuki K. Yamamoto;S. Kawamura
中科院分区：
文献类型：
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作者：
G. A. Nugroho;K. Yamaguchi;E. Nakakita;Masayuki K. Yamamoto;S. Kawamura
利用高分辨率边界层雷达（BLR）和小波观测微尺度的下降-上升气流组合。高分辨率BLR可以观测到推动稳定层的热活动。在此热过程中，还观察到下降气流和上升气流的组合。本研究对这一组合进行了详细的观察。利用保罗小波的一维连续小波变换，我们可以对这种基于高度和周期的下降气流-上升气流组合进行全局化。利用这一量化和不同天气条件下的小波方差，我们得到了这种微尺度下降气流-上升气流组合的基本周期为0 ~ 0.25 min、2 ~ 4 min和4 ~ 8 min。利用高分辨率边界层和小波对先进BLR在三种不同天气条件下测量的速度进行了基于尺度和高度的CWT 1D检验。量化的出现次数和小波方差表明，下行-上升结构的适宜周期分别为0 ~ 0.25 min、2 ~ 4 min和4 ~ 8 min。在未来的研究中，需要详细分析每个高度的方差。在本研究中，适当的母小波结合高分辨率BLR的垂直风速可以识别9天数据集（不同天气条件）的下降气流-上升气流组合。该技术加上功率谱和方差分析，可以确定周期并量化发生次数。这些信息对于理解与边界层微尺度条件有关的下降-上升气流行为，特别是对流条件下的上升-下降气流行为至关重要。
High-resolution boundary layer radar (BLR) and wavelet are utilized to observe microscale downdraft-updraft combinations. High-resolution BLR can observe thermal activity that pushed the stable layer. During this thermal, a combination of downdraft-updraft was also observed. A detailed observation of this com- bination was conducted in this study. Using a 1-dimensional continuous wavelet transform with Paul wavelet, we could quan- tify this downdraft-updraft combination based on the height and period. Using this quantification and wavelet variance in different weather conditions, we showed the essential period from 0 to 0.25 min, 2 to 4 min, and 4 to 8 min of this microscale downdraft- updraft combination. Utilization high-resolution boundary layer and wavelet to velocity measured by the advanced BLR in three different weather conditions is then examined using CWT 1D based on scale and height. The quantified number of occurrence and wavelet variance showed that the downdraft-updraft structure has a suitable period from 0 to 0.25 min, 2 to 4 min, and 4 to 8 min. Detailed analysis of the variance in every height is needed in future studies. An appropriate mother wavelet combined with vertical wind velocity from high-resolution BLR can identify the downdraft-updraft combination on a nine-day dataset (different weather conditions) in this study. This technique added with analysis of both power spectrum and variance could determine the period and quantified the number of occurrences. This information is essen tial for understanding the downdraft-updraft behavior related to the boundary layer microscale condition, especially in convective conditions.