[Objective] The research aimed to study the influences of GWDO parameterization scheme and terrain on a rainstorm in Dabie Mountain.[Method] By using NCEP/NCAR 1°×1° analytical data,the conventional and...[Objective] The research aimed to study the influences of GWDO parameterization scheme and terrain on a rainstorm in Dabie Mountain.[Method] By using NCEP/NCAR 1°×1° analytical data,the conventional and unconventional ground observation data,WRFV3.1.1 version of non-hydrostatic balance meso-scale mode,a meso-scale shear line rainstorm process which happened in Dabie Mountain zone during 05:00-14:00 on June 21,2008 was carried out the diagnostic analysis and numerical test.In the control experiment,the gravity wave drag by orography(GWDO) parameterization scheme was added.The influences of GWDO parameterization scheme and terrain on the rainstorm process were discussed respectively by the sensitivity test.[Result] The orography dragging coefficient had the good improvement role on the rainstorm intensity or falling zone.The result had the very big difference when considering or non-considering the orography dragging coefficient.After the parameterization scheme was added,the rainstorm intensity or falling zone was better than that of non-addition.When there was no dragging coefficient,the shear line disturbance was strong,and the gravity wave activity was obvious.The precipitation was stronger in the zone where the gravity wave was obvious.The terrain in Dabie Mountain and the surrounding place also had the important effect on the shear line precipitation.When the terrain in Dabie Mountain was removed,the precipitation intensity on the shear line increased significantly,and the strengthening of rain belt in the west was the most obvious.When the terrain in the southeast of Dabie Mountain was removed,the precipitation in the east had the obvious increasing effect.The terrain wasn’t favorable for the rainstorm strengthening.The intensity variation of rain belt not only related to the terrain,but also related to the disturbance variation on the shear line.[Conclusion] The research provided the theory basis for the prediction and forecast of rainstorm.展开更多
To remove vegetation bias(VB)from the global DEMs(GDEMs),an artificial neural network(ANN)-based method with the consideration of elevation spatial autocorrelation is developed in this paper.Three study sites with dif...To remove vegetation bias(VB)from the global DEMs(GDEMs),an artificial neural network(ANN)-based method with the consideration of elevation spatial autocorrelation is developed in this paper.Three study sites with different forest types(evergreen,mixed evergreen-deciduous,and deciduous)are employed to evaluate the performance of the proposed model on three popular 30-m GDEMs,including SRTM1,AW3D30,and COPDEM30.Taking LiDAR DTM as the ground truth,the accuracy of the GDEMs before and after VB correction is assessed,as well as two existing GDEMs including MERIT and FABDEM.Results show that all the original GDEMs significantly overestimate the LiDAR DTM in the three forest types,with the largest biases of 21.5 m for SRTM1,26.3 m for AW3D30,and 27.18 m for COPDEM30.Taking data randomly sampled from the corrected area as the training points,the proposed model reduces the mean errors(root mean square errors)of the three GDEMs by 98.8%-99.9%(55.1%-75.8%)in the three forests.When training data have the same forest type as the corrected GDEM but under different local situations,the proposed model lowers the GDEM errors by at least 76.9%(44.1%).Furthermore,our corrected GDEMs consistently outperform the existing GDEMs for the two cases.展开更多
区域气候模式对高原降水模拟存在系统性高估。该文从热力学角度考虑了局地(小尺度)地形对陆气过程的影响,以提高区域气候模式高原降水模拟能力。通过在天气研究与预报(weather research and forecasting, WRF)模式陆面过程模块耦合地形...区域气候模式对高原降水模拟存在系统性高估。该文从热力学角度考虑了局地(小尺度)地形对陆气过程的影响,以提高区域气候模式高原降水模拟能力。通过在天气研究与预报(weather research and forecasting, WRF)模式陆面过程模块耦合地形热力效应方案,将二维地形太阳辐射方案改进为三维地形太阳辐射方案,根据山区太阳辐射理论对太阳辐射直射、辐射散射、地形反射过程进行改进,得到改进方案;基于改进方案在亚东河谷开展高分辨率WRF模式降水模拟研究。结果表明:采用改进方案模拟的太阳辐射、降水结果与实测结果更接近,能够降低河谷降水高估的现象。改进方案能够体现出更多地形变化对地表辐射分布的影响:日间,山体坡面由于接收更多辐射得到加热(0.09~0.20℃),产生上升气流,在坡面形成更强上坡风(0.02~0.08 m/s),将河谷水汽携带到坡面以上,水汽在坡面以上区域爬升并形成降水,导致河谷区域降水减少(-4.54~-3.34 mm)、坡面以上区域降水增多(0.59~2.82 mm)。该研究对提高区域气候模式对山区降水的模拟效果具有重要意义。展开更多
基金Supported by National Key Basic Research Development Project Planning "973"(2009CB421503)National Natural Science Fund(40975037)Public Welfare Industry (Meteorology) Science Research Specific Item(GYHY200806009)
文摘[Objective] The research aimed to study the influences of GWDO parameterization scheme and terrain on a rainstorm in Dabie Mountain.[Method] By using NCEP/NCAR 1°×1° analytical data,the conventional and unconventional ground observation data,WRFV3.1.1 version of non-hydrostatic balance meso-scale mode,a meso-scale shear line rainstorm process which happened in Dabie Mountain zone during 05:00-14:00 on June 21,2008 was carried out the diagnostic analysis and numerical test.In the control experiment,the gravity wave drag by orography(GWDO) parameterization scheme was added.The influences of GWDO parameterization scheme and terrain on the rainstorm process were discussed respectively by the sensitivity test.[Result] The orography dragging coefficient had the good improvement role on the rainstorm intensity or falling zone.The result had the very big difference when considering or non-considering the orography dragging coefficient.After the parameterization scheme was added,the rainstorm intensity or falling zone was better than that of non-addition.When there was no dragging coefficient,the shear line disturbance was strong,and the gravity wave activity was obvious.The precipitation was stronger in the zone where the gravity wave was obvious.The terrain in Dabie Mountain and the surrounding place also had the important effect on the shear line precipitation.When the terrain in Dabie Mountain was removed,the precipitation intensity on the shear line increased significantly,and the strengthening of rain belt in the west was the most obvious.When the terrain in the southeast of Dabie Mountain was removed,the precipitation in the east had the obvious increasing effect.The terrain wasn’t favorable for the rainstorm strengthening.The intensity variation of rain belt not only related to the terrain,but also related to the disturbance variation on the shear line.[Conclusion] The research provided the theory basis for the prediction and forecast of rainstorm.
基金supported by the National Natural Science Foundation of China(grant number 42271438)the Shan-dong Provincial Natural Science Foundation of China(grant no.ZR2020YQ26)a project of the Shandong Province Higher Educational Youth Innovation Science and Technology Program(grant number 2019KJH007).
文摘To remove vegetation bias(VB)from the global DEMs(GDEMs),an artificial neural network(ANN)-based method with the consideration of elevation spatial autocorrelation is developed in this paper.Three study sites with different forest types(evergreen,mixed evergreen-deciduous,and deciduous)are employed to evaluate the performance of the proposed model on three popular 30-m GDEMs,including SRTM1,AW3D30,and COPDEM30.Taking LiDAR DTM as the ground truth,the accuracy of the GDEMs before and after VB correction is assessed,as well as two existing GDEMs including MERIT and FABDEM.Results show that all the original GDEMs significantly overestimate the LiDAR DTM in the three forest types,with the largest biases of 21.5 m for SRTM1,26.3 m for AW3D30,and 27.18 m for COPDEM30.Taking data randomly sampled from the corrected area as the training points,the proposed model reduces the mean errors(root mean square errors)of the three GDEMs by 98.8%-99.9%(55.1%-75.8%)in the three forests.When training data have the same forest type as the corrected GDEM but under different local situations,the proposed model lowers the GDEM errors by at least 76.9%(44.1%).Furthermore,our corrected GDEMs consistently outperform the existing GDEMs for the two cases.
文摘区域气候模式对高原降水模拟存在系统性高估。该文从热力学角度考虑了局地(小尺度)地形对陆气过程的影响,以提高区域气候模式高原降水模拟能力。通过在天气研究与预报(weather research and forecasting, WRF)模式陆面过程模块耦合地形热力效应方案,将二维地形太阳辐射方案改进为三维地形太阳辐射方案,根据山区太阳辐射理论对太阳辐射直射、辐射散射、地形反射过程进行改进,得到改进方案;基于改进方案在亚东河谷开展高分辨率WRF模式降水模拟研究。结果表明:采用改进方案模拟的太阳辐射、降水结果与实测结果更接近,能够降低河谷降水高估的现象。改进方案能够体现出更多地形变化对地表辐射分布的影响:日间,山体坡面由于接收更多辐射得到加热(0.09~0.20℃),产生上升气流,在坡面形成更强上坡风(0.02~0.08 m/s),将河谷水汽携带到坡面以上,水汽在坡面以上区域爬升并形成降水,导致河谷区域降水减少(-4.54~-3.34 mm)、坡面以上区域降水增多(0.59~2.82 mm)。该研究对提高区域气候模式对山区降水的模拟效果具有重要意义。
