Based on the observational hourly precipitation data and the European Centre for Medium-Range Weather Forecasts(ECMWF)Reanalysis 5(ERA5)products from 2006 to 2020,22 rainstorm processes in the eastern foot of Helan Mo...Based on the observational hourly precipitation data and the European Centre for Medium-Range Weather Forecasts(ECMWF)Reanalysis 5(ERA5)products from 2006 to 2020,22 rainstorm processes in the eastern foot of Helan Mountain are objectively classified by using the hierarchical clustering method,and the circulation characteristics of different patterns are comparatively analyzed in this study.The results show that the occurrences of rainstorm processes in the eastern foot of Helan Mountain are most closely related to three circulation patterns.PatternsⅠandⅢmainly occur in July and August,with similar zonal circulations in synoptic backgrounds.Specifically,the South Asia high and the western Pacific subtropical high are stronger and more northward than those in normal years.The frontal systems in westerlies are inactive,while the water vapor from the ocean surface in the south is mainly transported to the rainstorm area by the southerly jet stream at 700 h Pa.The dynamic lifting anomalies are relatively weak,the instability of atmospheric stratification is anomalously strong,and thus the localized severe convective rainstorm is more significant.Comparatively,rainstorm processes of patternⅠare accompanied by stronger and deeper ascending motions,and the warm-sector rainstorm is more extreme.PatternⅢshows a stronger and deeper convective instability,accompanied by larger low-level moisture.Rainstorm processes of patternⅡmainly occur in early summer and early autumn,presenting a meridional circulation pattern of high in the east and low in the west in terms of geopotential height.Moreover,the two low-level jets transporting the water vapor northward from the ocean on the east of China encounter with the frontal systems in westerlies,which makes the ascending motion in patternⅡanomalously strong and deep.The relatively weak instability of atmospheric stratification causes weak convection and long-lasting precipitation formed by the confluence of cold air and warm air.This study may help improve rainstorm forecasting in arid regions.展开更多
Cabernet Sauvignon grapes in the wine-producing area of Helan Mountain,East Ningxia,China,were the research object in this study.The dissection of the roots and branching stems method was used to explore the dynamic c...Cabernet Sauvignon grapes in the wine-producing area of Helan Mountain,East Ningxia,China,were the research object in this study.The dissection of the roots and branching stems method was used to explore the dynamic changes in the nitrogen,phosphorus,and potassium nutrient requirements of wine grapes over a number of growth stages.The results showed that over the whole growth period,the nitrogen content of the roots was the highest during the leaf-expansion stage and lowest during the turning-color stage,and that the nitrogen content of the leaves and fruit showed a downward trend as growth progressed.The nitrogen content of the secondary branches was the lowest during the fruit expansion stage and the highest during the leaf-expansion stage;and the phosphorus content of the roots was the highest during the leaf-expansion stage and lowest during the fruit expansion stage.The phosphorus content of the trunk and primary branches showed a trend of“rising-falling-rising”.The phosphorus content of the leaves and secondary branches was the lowest during the turning-color stage,whereas the phosphorus content of the fruit was at its highest during this stage.The potassium contents of the secondary branches and fruit showed a downward trend,but the potassium content of the leaves was highest during the fruit expansion stage and lowest in the nutrient return stage.Over the whole growth period,the accumulation of nitrogen,phosphorus,and potassium in wine grapes was 129.92 kg/hm2,41.51 kg/hm2,and 189.47 kg/hm2,respectively,the total requirements for N,P2O5,and K2O were 262.38 kg/hm2,288.15 kg/hm2,and 569.04 kg/hm2,respectively,and the reasonable nutrient requirement ratio was 1.00:1.10:2.17.展开更多
为提升贺兰山东麓葡萄园晚霜冻灾害精细化防御能力,利用2020—2023年4—5月贺兰山东麓葡萄园农田小气候站最低气温观测数据,分析葡萄园最低气温变化特征、晚霜冻发生频率和区域分布特征,并基于欧洲中期天气预报中心(European Centre for...为提升贺兰山东麓葡萄园晚霜冻灾害精细化防御能力,利用2020—2023年4—5月贺兰山东麓葡萄园农田小气候站最低气温观测数据,分析葡萄园最低气温变化特征、晚霜冻发生频率和区域分布特征,并基于欧洲中期天气预报中心(European Centre for Medium-Range Weather Forecasts,ECMWF)模式预报产品和宁夏地区格点气温实况,采用径向基函数(Radial Basis Function,RBF)神经网络算法,构建贺兰山东麓葡萄园最低气温和霜冻预报模型。结果表明:贺兰山东麓葡萄园轻霜冻最为普遍,其次是中霜冻,4月是霜冻发生的主要月份,东方裕兴酒庄霜冻出现最频繁,观兰酒庄霜冻最少,红寺堡产区是霜冻易发区。最低气温和霜冻预报检验结果显示,与ECMWF模式相比,RBF模型对贺兰、永宁和红寺堡产区的最低气温预报准确率提高,最高提升幅度达33.8%,平均绝对误差降低0.20~1.50℃。从单站霜冻预报看,RBF模型有明显优势,准确率普遍提升1.0%~14.0%,平均绝对误差降低0.04~0.37℃;从产区平均看,RBF模型对红寺堡产区霜冻预报准确率提高最多,达13.0%。在针对霜冻的实例分析中,RBF模型预报效果更优,特别是对中霜冻预报优势明显,相比ECMWF模式准确率提升25.0%~50.0%,平均绝对误差降低1.80~2.10℃。展开更多
基金National Natural Science Foundation of China(41965001)Program of Technology and Innovation for Leading Talents in Ningxia Hui Autonomous Region(2021GKLRLX05)。
文摘Based on the observational hourly precipitation data and the European Centre for Medium-Range Weather Forecasts(ECMWF)Reanalysis 5(ERA5)products from 2006 to 2020,22 rainstorm processes in the eastern foot of Helan Mountain are objectively classified by using the hierarchical clustering method,and the circulation characteristics of different patterns are comparatively analyzed in this study.The results show that the occurrences of rainstorm processes in the eastern foot of Helan Mountain are most closely related to three circulation patterns.PatternsⅠandⅢmainly occur in July and August,with similar zonal circulations in synoptic backgrounds.Specifically,the South Asia high and the western Pacific subtropical high are stronger and more northward than those in normal years.The frontal systems in westerlies are inactive,while the water vapor from the ocean surface in the south is mainly transported to the rainstorm area by the southerly jet stream at 700 h Pa.The dynamic lifting anomalies are relatively weak,the instability of atmospheric stratification is anomalously strong,and thus the localized severe convective rainstorm is more significant.Comparatively,rainstorm processes of patternⅠare accompanied by stronger and deeper ascending motions,and the warm-sector rainstorm is more extreme.PatternⅢshows a stronger and deeper convective instability,accompanied by larger low-level moisture.Rainstorm processes of patternⅡmainly occur in early summer and early autumn,presenting a meridional circulation pattern of high in the east and low in the west in terms of geopotential height.Moreover,the two low-level jets transporting the water vapor northward from the ocean on the east of China encounter with the frontal systems in westerlies,which makes the ascending motion in patternⅡanomalously strong and deep.The relatively weak instability of atmospheric stratification causes weak convection and long-lasting precipitation formed by the confluence of cold air and warm air.This study may help improve rainstorm forecasting in arid regions.
基金This work was supported by Ningxia Key Research and Development Project(2020BCF01003)Science Technology Innovation Guidance Project of Ningxia Academy of Agriculture and Forestry Sciences(NKYZZ-J-19-04)Ningxia Natural Science Foundation(2020AAC02011).
文摘Cabernet Sauvignon grapes in the wine-producing area of Helan Mountain,East Ningxia,China,were the research object in this study.The dissection of the roots and branching stems method was used to explore the dynamic changes in the nitrogen,phosphorus,and potassium nutrient requirements of wine grapes over a number of growth stages.The results showed that over the whole growth period,the nitrogen content of the roots was the highest during the leaf-expansion stage and lowest during the turning-color stage,and that the nitrogen content of the leaves and fruit showed a downward trend as growth progressed.The nitrogen content of the secondary branches was the lowest during the fruit expansion stage and the highest during the leaf-expansion stage;and the phosphorus content of the roots was the highest during the leaf-expansion stage and lowest during the fruit expansion stage.The phosphorus content of the trunk and primary branches showed a trend of“rising-falling-rising”.The phosphorus content of the leaves and secondary branches was the lowest during the turning-color stage,whereas the phosphorus content of the fruit was at its highest during this stage.The potassium contents of the secondary branches and fruit showed a downward trend,but the potassium content of the leaves was highest during the fruit expansion stage and lowest in the nutrient return stage.Over the whole growth period,the accumulation of nitrogen,phosphorus,and potassium in wine grapes was 129.92 kg/hm2,41.51 kg/hm2,and 189.47 kg/hm2,respectively,the total requirements for N,P2O5,and K2O were 262.38 kg/hm2,288.15 kg/hm2,and 569.04 kg/hm2,respectively,and the reasonable nutrient requirement ratio was 1.00:1.10:2.17.
文摘为提升贺兰山东麓葡萄园晚霜冻灾害精细化防御能力,利用2020—2023年4—5月贺兰山东麓葡萄园农田小气候站最低气温观测数据,分析葡萄园最低气温变化特征、晚霜冻发生频率和区域分布特征,并基于欧洲中期天气预报中心(European Centre for Medium-Range Weather Forecasts,ECMWF)模式预报产品和宁夏地区格点气温实况,采用径向基函数(Radial Basis Function,RBF)神经网络算法,构建贺兰山东麓葡萄园最低气温和霜冻预报模型。结果表明:贺兰山东麓葡萄园轻霜冻最为普遍,其次是中霜冻,4月是霜冻发生的主要月份,东方裕兴酒庄霜冻出现最频繁,观兰酒庄霜冻最少,红寺堡产区是霜冻易发区。最低气温和霜冻预报检验结果显示,与ECMWF模式相比,RBF模型对贺兰、永宁和红寺堡产区的最低气温预报准确率提高,最高提升幅度达33.8%,平均绝对误差降低0.20~1.50℃。从单站霜冻预报看,RBF模型有明显优势,准确率普遍提升1.0%~14.0%,平均绝对误差降低0.04~0.37℃;从产区平均看,RBF模型对红寺堡产区霜冻预报准确率提高最多,达13.0%。在针对霜冻的实例分析中,RBF模型预报效果更优,特别是对中霜冻预报优势明显,相比ECMWF模式准确率提升25.0%~50.0%,平均绝对误差降低1.80~2.10℃。
