为了进一步认识上升气流对雷暴云内复杂电荷结构特征的影响,利用加入起放电参数化方案的WRF模式对DC3试验中2012年6月6日一次出现反极性电荷结构的强雷暴过程进行模拟。结果表明,起电区对应强回波区,主要发生在上升气流区中心云水混合...为了进一步认识上升气流对雷暴云内复杂电荷结构特征的影响,利用加入起放电参数化方案的WRF模式对DC3试验中2012年6月6日一次出现反极性电荷结构的强雷暴过程进行模拟。结果表明,起电区对应强回波区,主要发生在上升气流区中心云水混合比大于0.2 g kg^(-1)的冰水混合区,非感应起电机制主导着雷暴云内的起电过程。上升气流区外围区域存在可观的电荷,主要是由气流将起电区域的荷电粒子向后水平输送形成的。同类粒子带电极性在较大范围内变化少,但由于各类粒子的含量和荷电量不同,导致净电荷密度分布呈现较复杂的结构。达到一定强度的上升气流可以破坏电荷区的连续性,导致对流区出现高密度的、正负极性交错分布的、范围更小的电荷区。层云区由于没有上升气流,荷电粒子主要源自上升气流区的水平输送,所以其电荷区分布较连续且范围较大,但电荷密度相对弱。处于不同生命期的单体由于上升气流强度和倾斜程度不同,单体间的水成物粒子分布特征会存在一定差异,使得反转温度和起电率出现较大不同,因此单体合并时上升气流区之间的电荷区更破碎,电荷结构更复杂。展开更多
In September 2020,a pioneering observational network of three X-band phased-array radars(XPARs)was established in Xiamen,a subtropical coastal and densely populated city in southeastern China.Statistically,this study ...In September 2020,a pioneering observational network of three X-band phased-array radars(XPARs)was established in Xiamen,a subtropical coastal and densely populated city in southeastern China.Statistically,this study demonstrated that the XPAR network outperforms single S-band radar in revealing the warm-season convective storms in Xiamen in a fine-scale manner.The findings revealed that convective activity in Xiamen is most frequent in the central and northern mountainous regions,with lower frequency observed in the southern coastal areas.The diurnal pattern of convection occurrence exhibited a unimodal distribution,with a peak in the afternoon.The frequent occurrence of convective storms correlates well in both time and space with the active terrain uplift that occurs when the prevailing winds encounter mountainous areas.Notably,September stands apart with a bimodal diurnal pattern,featuring a prominent afternoon peak and a significant secondary peak before midnight.Further examination of dense rain gauge data in Xiamen indicates that high-frequency areas of short-duration heavy rainfall largely coincide with regions of active convective storms,except for a unique rainfall hotspot in southern Xiamen,where moderate convection frequency is accompanied by substantial rainfall.This anomalous rainfall,predominantly nocturnal,appears less influenced by terrain uplift and exhibits higher precipitation efficiency than daytime rainfall.These preliminary findings offer insights into the characteristics of convection occurrence in Xiamen's subtropical coastal environment and hold promise for enhancing the accuracy of convection and precipitation forecasts in similar environments.展开更多
文摘为了进一步认识上升气流对雷暴云内复杂电荷结构特征的影响,利用加入起放电参数化方案的WRF模式对DC3试验中2012年6月6日一次出现反极性电荷结构的强雷暴过程进行模拟。结果表明,起电区对应强回波区,主要发生在上升气流区中心云水混合比大于0.2 g kg^(-1)的冰水混合区,非感应起电机制主导着雷暴云内的起电过程。上升气流区外围区域存在可观的电荷,主要是由气流将起电区域的荷电粒子向后水平输送形成的。同类粒子带电极性在较大范围内变化少,但由于各类粒子的含量和荷电量不同,导致净电荷密度分布呈现较复杂的结构。达到一定强度的上升气流可以破坏电荷区的连续性,导致对流区出现高密度的、正负极性交错分布的、范围更小的电荷区。层云区由于没有上升气流,荷电粒子主要源自上升气流区的水平输送,所以其电荷区分布较连续且范围较大,但电荷密度相对弱。处于不同生命期的单体由于上升气流强度和倾斜程度不同,单体间的水成物粒子分布特征会存在一定差异,使得反转温度和起电率出现较大不同,因此单体合并时上升气流区之间的电荷区更破碎,电荷结构更复杂。
基金Natural Science Foundation of Fujian Province(2023J011338)Guided Foundation of Xiamen Science and Technology Bureau(3502Z20214ZD4009,3502Z20214ZD4010)+1 种基金Key Projects of East China Phased Array Weather Radar Application Joint Laboratory(EPJL_RP2025010)National Natural Science Foundation of China(41905049)。
文摘In September 2020,a pioneering observational network of three X-band phased-array radars(XPARs)was established in Xiamen,a subtropical coastal and densely populated city in southeastern China.Statistically,this study demonstrated that the XPAR network outperforms single S-band radar in revealing the warm-season convective storms in Xiamen in a fine-scale manner.The findings revealed that convective activity in Xiamen is most frequent in the central and northern mountainous regions,with lower frequency observed in the southern coastal areas.The diurnal pattern of convection occurrence exhibited a unimodal distribution,with a peak in the afternoon.The frequent occurrence of convective storms correlates well in both time and space with the active terrain uplift that occurs when the prevailing winds encounter mountainous areas.Notably,September stands apart with a bimodal diurnal pattern,featuring a prominent afternoon peak and a significant secondary peak before midnight.Further examination of dense rain gauge data in Xiamen indicates that high-frequency areas of short-duration heavy rainfall largely coincide with regions of active convective storms,except for a unique rainfall hotspot in southern Xiamen,where moderate convection frequency is accompanied by substantial rainfall.This anomalous rainfall,predominantly nocturnal,appears less influenced by terrain uplift and exhibits higher precipitation efficiency than daytime rainfall.These preliminary findings offer insights into the characteristics of convection occurrence in Xiamen's subtropical coastal environment and hold promise for enhancing the accuracy of convection and precipitation forecasts in similar environments.
