利用气象与化学模块在线耦合的模式WRF-Chem V3.5(Weather Research and Forecasting Model coupled to Chemistry Version 3.5)对1323号台风Fitow进行了模拟,设计无人为排放源、含人为排放源和人为排放源增加的三组模拟试验,对比分析...利用气象与化学模块在线耦合的模式WRF-Chem V3.5(Weather Research and Forecasting Model coupled to Chemistry Version 3.5)对1323号台风Fitow进行了模拟,设计无人为排放源、含人为排放源和人为排放源增加的三组模拟试验,对比分析了人为气溶胶对台风的影响。结果表明:人为气溶胶对台风移动路径影响较小。人为气溶胶增加,台风强度减弱,台风主体总累积降水量减少,靠近陆地阶段台风主体降水率减少。气溶胶的增多可提供更多的凝结核,台风外围云水增加,更多的云水可上升至冻结层以上形成过冷水,促进冰相粒子的形成,释放的潜热增加,使外围对流增强,降水增加。台风外围对流的发展,使低层入流的暖湿空气更多的在外围上升,向台风中心的入流减弱,眼墙的发展减弱,降水减少,台风强度减弱。台风外围的对流发展弱于眼墙的对流,降水仍以眼墙区为主,使累积降水量和降水率整体上表现为减少。展开更多
为给通过地形复杂,缺少气象资料的西南艰险山区的铁路研究风吹雪易发性提供方法,以位于该区域的四川省康定市为例,采用中尺度数值天气预报模式(The Weather Research and Forecasting Mode,WRF)对该区域气象要素的时空分布进行模拟.基于...为给通过地形复杂,缺少气象资料的西南艰险山区的铁路研究风吹雪易发性提供方法,以位于该区域的四川省康定市为例,采用中尺度数值天气预报模式(The Weather Research and Forecasting Mode,WRF)对该区域气象要素的时空分布进行模拟.基于WRF模式中各种参数的特点,设计4种参数方案进行计算,采用双层网格嵌套达到降尺度模拟,为了高精度解析大气边界层过程,在竖直方向、近地面1.5km高度内加密为15层,提取康定站计算结果与观测结果进行比较.结果表明,WRF模式的计算结果符合康定市气候特征,气象要素的相关系数均高于0.5;风吹雪发生概率从高到低的区域依次为康定市东部和南部边缘的贡嘎山区,内部的大雪山段,以及位于101.7°E~102.0°E位置处的铁路线路,概率分别为19%、14%和12%,其他区域的概率低于4%.展开更多
WRF(weather research and forecasting)模式中参数化方案的选择与近地面风场的仿真模拟结果关系密切。为解决新疆北部不同地形地区风场模拟准确性的问题,采用WRF中尺度气象模式,探究4类参数化方案(边界层、微物理、陆面过程、近地面层...WRF(weather research and forecasting)模式中参数化方案的选择与近地面风场的仿真模拟结果关系密切。为解决新疆北部不同地形地区风场模拟准确性的问题,采用WRF中尺度气象模式,探究4类参数化方案(边界层、微物理、陆面过程、近地面层)以及次网格地形方案对新疆北部不同地形地区风场模拟结果的影响。结果表明:每组试验均能模拟出风速的变化趋势;陆面过程RUC(rapid update cycle)方案和微物理Lin(Purdue Lin)方案对平原地区模拟结果较好,陆面过程Noah方案和微物理WSM6(WRF single moment 6 class)方案对山区地形模拟结果较好,且对于平原和山谷地形,次网格地形方案对模拟地区均能起到较好的修正作用。展开更多
利用中尺度数值模式WRF研究积云对流参数化方案和模式分辨率对青藏高原玉树地区夏季的一次层状云降水的影响。通过模拟结果分析表明:采用WRF模拟高原降水结果普遍偏大,三种积云参数化方案中GD方案模拟结果比较理想,不同方案对降水模拟...利用中尺度数值模式WRF研究积云对流参数化方案和模式分辨率对青藏高原玉树地区夏季的一次层状云降水的影响。通过模拟结果分析表明:采用WRF模拟高原降水结果普遍偏大,三种积云参数化方案中GD方案模拟结果比较理想,不同方案对降水模拟比较敏感,相同方案下不同网格分辨率模拟降水分布基本相同。所用设计方案模拟的结果基本反映此次降水的实况和云图特征。在模拟实况温度和露点温度时,5 km分辨率的BMJ方案模拟效果相对于同分辨率其他两种方案明显更好。结合物理量场以及卫星云图分析本次层状云降水是由环流形势稳定、水汽充足、高原风切变共同影响。利用高分辨率的日本葵花8号卫星分析8 um和11 um红外通道分析云辐射亮温和水汽情况,降水时段玉树地区上空存在片状层云,并且水汽条件充足,环流背景场上玉树地区位于槽前,积云对流旺盛。此外,夜间露点温度差减小有利于形成较厚的云系导致高原夜间降水频繁。云图上发现,上升流场维持层状云团的发展和移动,高原夜间低层出现小而多的水汽云团,较小的云团混合生成较大的降水云系。The mesoscale numerical model WRF was used to study the effects of cumulus convection scheme and model resolution on the precipitation of stratiform clouds in Yushu over the Qinghai-Xizang Plateau in summer. Analysis of simulation results shows that WRF tends to overestimate precipitation over the plateau. Among the three cumulus parameterization schemes, the GD scheme yields relatively ideal simulation results, and different schemes exhibit sensitivity in precipitation simulation. Under the same scheme, different grid resolutions yield similar precipitation distributions. The simulated results using the designated schemes generally reflect the actual conditions and cloud features of this precipitation event. When simulating observed temperature and dew point temperature, the BMJ scheme at 5km resolution performs significantly better compared to the other two schemes at the same resolution. Combining physical field analysis and satellite cloud images, it is concluded that the stratiform cloud precipitation during this event is influenced by stable circulation patterns, abundant moisture, and wind shear over the plateau. High-resolution data from the Japanese Himawari-8 satellite’s 8um and 11um infrared channels reveal cloud radiative temperatures and moisture conditions. During the precipitation period, patchy stratiform clouds are present over the Yushu area with sufficient moisture, and the circulation background places Yushu ahead of a trough, promoting vigorous cumulus convection. Additionally, the reduced temperature-dew point temperature difference at night favors the formation of thick cloud systems, leading to frequent nighttime precipitation over the plateau. Analysis of cloud images indicates that the updraft field sustains the development and movement of stratiform cloud clusters, while small and numerous water vapor cloud clusters appear in the lower atmosphere at night, mixing to form larger precipitation cloud systems.展开更多
青藏高原是全球气候变化的敏感地区,该地区的降水变化对全球及区域气候系统影响深远。运用WRF模型对高原的降水状况进行模拟研究,可以揭示降水形成机制和变化规律。但目前缺少利用WRF模式的不同组合改进青藏高原降水高估。为了改善降水...青藏高原是全球气候变化的敏感地区,该地区的降水变化对全球及区域气候系统影响深远。运用WRF模型对高原的降水状况进行模拟研究,可以揭示降水形成机制和变化规律。但目前缺少利用WRF模式的不同组合改进青藏高原降水高估。为了改善降水高估的问题,本研究利用区域气候站逐时降水实况资料和NCEP 0.25度的3小时全球再分析格点资料,采用WRF4.0,对2019年7月28日发生在玉树地区的降水事件进行了对比分析,涉及多种积云对流方案与分辨率的组合。通过比较各种方案对降水量及降水分布的模拟效果,从而得到了相关的研究结论:不同积云对流参数化方案对降水落区和强度模拟的影响显著,GD方案在降水区域模拟上效果最好,与实际降水空间分布相似性最大,而BMJ方案效果最差。总体来看,各方案均普遍高估降水量,提高模式水平分辨率可以提高降水模拟精度,但对雨带走向和范围影响不大。模式能很好地模拟降水演变过程及其后的温度、露点、CAPE和风场等物理量,除NKF-5 km方案外,其余方案的CAPE模拟结果基本与实际一致。NKF方案倾向于产生更高的CAPE,这可能是其降水模拟效果较差的原因。The Tibetan Plateau is a sensitive region for global climate change, and variations in precipitation in this area have far-reaching impacts on both global and regional climate systems. Conducting simulation studies on precipitation conditions in the plateau using the WRF model can reveal mechanisms and patterns of precipitation formation. However, there is currently a lack of research utilizing different combinations of the WRF model to improve the overestimation of precipitation on the Tibetan Plateau. To address this overestimation issue, this study utilized hourly precipitation data from regional climate stations and 3-hourly global reanalysis grid data from NCEP with a resolution of 0.25 degrees. The WRF model was employed to conduct comparative analyses of a precipitation event that occurred in the Yushu region on July 28, 2019, involving various combinations of cumulus convection schemes and resolutions. By comparing the simulation effects of different schemes on precipitation amount and distribution, the study drew relevant conclusions: different cumulus convection schemes significantly affect the simulation of precipitation regions and intensity. The GD scheme performed the best in simulating precipitation areas, exhibiting the highest similarity to the actual spatial distribution of precipitation, while the BMJ scheme performed the worst. Overall, all schemes tended to overestimate precipitation amounts. Increasing the model’s horizontal resolution can enhance precipitation simulation accuracy but has a minimal impact on the direction and extent of rain belts. The model effectively simulates the evolution of precipitation and subsequent physical quantities such as temperature, dew point, CAPE, and wind fields. With the exception of the NKF-5 km scheme, the CAPE simulation results of the other schemes were generally consistent with actual observations. The NKF scheme tends to produce higher CAPE, which may be a contributing factor to its poorer precipitation simulation performance.展开更多
文摘利用气象与化学模块在线耦合的模式WRF-Chem V3.5(Weather Research and Forecasting Model coupled to Chemistry Version 3.5)对1323号台风Fitow进行了模拟,设计无人为排放源、含人为排放源和人为排放源增加的三组模拟试验,对比分析了人为气溶胶对台风的影响。结果表明:人为气溶胶对台风移动路径影响较小。人为气溶胶增加,台风强度减弱,台风主体总累积降水量减少,靠近陆地阶段台风主体降水率减少。气溶胶的增多可提供更多的凝结核,台风外围云水增加,更多的云水可上升至冻结层以上形成过冷水,促进冰相粒子的形成,释放的潜热增加,使外围对流增强,降水增加。台风外围对流的发展,使低层入流的暖湿空气更多的在外围上升,向台风中心的入流减弱,眼墙的发展减弱,降水减少,台风强度减弱。台风外围的对流发展弱于眼墙的对流,降水仍以眼墙区为主,使累积降水量和降水率整体上表现为减少。
文摘为给通过地形复杂,缺少气象资料的西南艰险山区的铁路研究风吹雪易发性提供方法,以位于该区域的四川省康定市为例,采用中尺度数值天气预报模式(The Weather Research and Forecasting Mode,WRF)对该区域气象要素的时空分布进行模拟.基于WRF模式中各种参数的特点,设计4种参数方案进行计算,采用双层网格嵌套达到降尺度模拟,为了高精度解析大气边界层过程,在竖直方向、近地面1.5km高度内加密为15层,提取康定站计算结果与观测结果进行比较.结果表明,WRF模式的计算结果符合康定市气候特征,气象要素的相关系数均高于0.5;风吹雪发生概率从高到低的区域依次为康定市东部和南部边缘的贡嘎山区,内部的大雪山段,以及位于101.7°E~102.0°E位置处的铁路线路,概率分别为19%、14%和12%,其他区域的概率低于4%.
文摘WRF(weather research and forecasting)模式中参数化方案的选择与近地面风场的仿真模拟结果关系密切。为解决新疆北部不同地形地区风场模拟准确性的问题,采用WRF中尺度气象模式,探究4类参数化方案(边界层、微物理、陆面过程、近地面层)以及次网格地形方案对新疆北部不同地形地区风场模拟结果的影响。结果表明:每组试验均能模拟出风速的变化趋势;陆面过程RUC(rapid update cycle)方案和微物理Lin(Purdue Lin)方案对平原地区模拟结果较好,陆面过程Noah方案和微物理WSM6(WRF single moment 6 class)方案对山区地形模拟结果较好,且对于平原和山谷地形,次网格地形方案对模拟地区均能起到较好的修正作用。
文摘利用中尺度数值模式WRF研究积云对流参数化方案和模式分辨率对青藏高原玉树地区夏季的一次层状云降水的影响。通过模拟结果分析表明:采用WRF模拟高原降水结果普遍偏大,三种积云参数化方案中GD方案模拟结果比较理想,不同方案对降水模拟比较敏感,相同方案下不同网格分辨率模拟降水分布基本相同。所用设计方案模拟的结果基本反映此次降水的实况和云图特征。在模拟实况温度和露点温度时,5 km分辨率的BMJ方案模拟效果相对于同分辨率其他两种方案明显更好。结合物理量场以及卫星云图分析本次层状云降水是由环流形势稳定、水汽充足、高原风切变共同影响。利用高分辨率的日本葵花8号卫星分析8 um和11 um红外通道分析云辐射亮温和水汽情况,降水时段玉树地区上空存在片状层云,并且水汽条件充足,环流背景场上玉树地区位于槽前,积云对流旺盛。此外,夜间露点温度差减小有利于形成较厚的云系导致高原夜间降水频繁。云图上发现,上升流场维持层状云团的发展和移动,高原夜间低层出现小而多的水汽云团,较小的云团混合生成较大的降水云系。The mesoscale numerical model WRF was used to study the effects of cumulus convection scheme and model resolution on the precipitation of stratiform clouds in Yushu over the Qinghai-Xizang Plateau in summer. Analysis of simulation results shows that WRF tends to overestimate precipitation over the plateau. Among the three cumulus parameterization schemes, the GD scheme yields relatively ideal simulation results, and different schemes exhibit sensitivity in precipitation simulation. Under the same scheme, different grid resolutions yield similar precipitation distributions. The simulated results using the designated schemes generally reflect the actual conditions and cloud features of this precipitation event. When simulating observed temperature and dew point temperature, the BMJ scheme at 5km resolution performs significantly better compared to the other two schemes at the same resolution. Combining physical field analysis and satellite cloud images, it is concluded that the stratiform cloud precipitation during this event is influenced by stable circulation patterns, abundant moisture, and wind shear over the plateau. High-resolution data from the Japanese Himawari-8 satellite’s 8um and 11um infrared channels reveal cloud radiative temperatures and moisture conditions. During the precipitation period, patchy stratiform clouds are present over the Yushu area with sufficient moisture, and the circulation background places Yushu ahead of a trough, promoting vigorous cumulus convection. Additionally, the reduced temperature-dew point temperature difference at night favors the formation of thick cloud systems, leading to frequent nighttime precipitation over the plateau. Analysis of cloud images indicates that the updraft field sustains the development and movement of stratiform cloud clusters, while small and numerous water vapor cloud clusters appear in the lower atmosphere at night, mixing to form larger precipitation cloud systems.
文摘青藏高原是全球气候变化的敏感地区,该地区的降水变化对全球及区域气候系统影响深远。运用WRF模型对高原的降水状况进行模拟研究,可以揭示降水形成机制和变化规律。但目前缺少利用WRF模式的不同组合改进青藏高原降水高估。为了改善降水高估的问题,本研究利用区域气候站逐时降水实况资料和NCEP 0.25度的3小时全球再分析格点资料,采用WRF4.0,对2019年7月28日发生在玉树地区的降水事件进行了对比分析,涉及多种积云对流方案与分辨率的组合。通过比较各种方案对降水量及降水分布的模拟效果,从而得到了相关的研究结论:不同积云对流参数化方案对降水落区和强度模拟的影响显著,GD方案在降水区域模拟上效果最好,与实际降水空间分布相似性最大,而BMJ方案效果最差。总体来看,各方案均普遍高估降水量,提高模式水平分辨率可以提高降水模拟精度,但对雨带走向和范围影响不大。模式能很好地模拟降水演变过程及其后的温度、露点、CAPE和风场等物理量,除NKF-5 km方案外,其余方案的CAPE模拟结果基本与实际一致。NKF方案倾向于产生更高的CAPE,这可能是其降水模拟效果较差的原因。The Tibetan Plateau is a sensitive region for global climate change, and variations in precipitation in this area have far-reaching impacts on both global and regional climate systems. Conducting simulation studies on precipitation conditions in the plateau using the WRF model can reveal mechanisms and patterns of precipitation formation. However, there is currently a lack of research utilizing different combinations of the WRF model to improve the overestimation of precipitation on the Tibetan Plateau. To address this overestimation issue, this study utilized hourly precipitation data from regional climate stations and 3-hourly global reanalysis grid data from NCEP with a resolution of 0.25 degrees. The WRF model was employed to conduct comparative analyses of a precipitation event that occurred in the Yushu region on July 28, 2019, involving various combinations of cumulus convection schemes and resolutions. By comparing the simulation effects of different schemes on precipitation amount and distribution, the study drew relevant conclusions: different cumulus convection schemes significantly affect the simulation of precipitation regions and intensity. The GD scheme performed the best in simulating precipitation areas, exhibiting the highest similarity to the actual spatial distribution of precipitation, while the BMJ scheme performed the worst. Overall, all schemes tended to overestimate precipitation amounts. Increasing the model’s horizontal resolution can enhance precipitation simulation accuracy but has a minimal impact on the direction and extent of rain belts. The model effectively simulates the evolution of precipitation and subsequent physical quantities such as temperature, dew point, CAPE, and wind fields. With the exception of the NKF-5 km scheme, the CAPE simulation results of the other schemes were generally consistent with actual observations. The NKF scheme tends to produce higher CAPE, which may be a contributing factor to its poorer precipitation simulation performance.
