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
The eastern foothills of the Helan Mountains in China are a typical mountainous region of soil and gravel,where gravel could affect the water movement process in the soil.This study focused on the effects of different...The eastern foothills of the Helan Mountains in China are a typical mountainous region of soil and gravel,where gravel could affect the water movement process in the soil.This study focused on the effects of different gravel contents on the water absorption characteristics and hydraulic parameters of stony soil.The stony soil samples were collected from the eastern foothills of the Helan Mountains in April 2023 and used as the experimental materials to conduct a one-dimensional horizontal soil column absorption experiment.Six experimental groups with gravel contents of 0%,10%,20%,30%,40%,and 50%were established to determine the saturated hydraulic conductivity(K_(s)),saturated water content(θ_(s)),initial water content(θ_(i)),and retention water content(θ_(r)),and explore the changes in the wetting front depth and cumulative absorption volume during the absorption experiment.The Philip model was used to fit the soil absorption process and determine the soil water absorption rate.Then the length of the characteristic wetting front depth,shape coefficient,empirical parameter,inverse intake suction and soil water suction were derived from the van Genuchten model.Finally,the hydraulic parameters mentioned above were used to fit the soil water characteristic curves,unsaturated hydraulic conductivity(K_(θ))and specific water capacity(C(h)).The results showed that the wetting front depth and cumulative absorption volume of each treatment gradually decreased with increasing gravel content.Compared with control check treatment with gravel content of 0%,soil water absorption rates in the treatments with gravel contents of 10%,20%,30%,40%,and 50%decreased by 11.47%,17.97%,25.24%,29.83%,and 42.45%,respectively.As the gravel content increased,inverse intake suction gradually increased,and shape coefficient,K_(s),θ_(s),andθ_(r)gradually decreased.For the same soil water content,soil water suction and K_(θ)gradually decreased with increasing gravel content.At the same soil water suction,C(h)decreased with increasing gravel content,and the water use efficiency worsened.Overall,the water holding capacity,hydraulic conductivity,and water use efficiency of stony soil in the eastern foothills of the Helan Mountains decreased with increasing gravel content.This study could provide data support for improving soil water use efficiency in the eastern foothills of the Helan Mountains and other similar rocky mountainous areas.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
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funded by the National Natural Science Foundation of China(32360321)the Natural Science Foundation of Ningxia Hui Autonomous Region,China(2023AAC03046,2023AAC02018)the Ningxia Key Research and Development Project(2021BEG02011).
文摘The eastern foothills of the Helan Mountains in China are a typical mountainous region of soil and gravel,where gravel could affect the water movement process in the soil.This study focused on the effects of different gravel contents on the water absorption characteristics and hydraulic parameters of stony soil.The stony soil samples were collected from the eastern foothills of the Helan Mountains in April 2023 and used as the experimental materials to conduct a one-dimensional horizontal soil column absorption experiment.Six experimental groups with gravel contents of 0%,10%,20%,30%,40%,and 50%were established to determine the saturated hydraulic conductivity(K_(s)),saturated water content(θ_(s)),initial water content(θ_(i)),and retention water content(θ_(r)),and explore the changes in the wetting front depth and cumulative absorption volume during the absorption experiment.The Philip model was used to fit the soil absorption process and determine the soil water absorption rate.Then the length of the characteristic wetting front depth,shape coefficient,empirical parameter,inverse intake suction and soil water suction were derived from the van Genuchten model.Finally,the hydraulic parameters mentioned above were used to fit the soil water characteristic curves,unsaturated hydraulic conductivity(K_(θ))and specific water capacity(C(h)).The results showed that the wetting front depth and cumulative absorption volume of each treatment gradually decreased with increasing gravel content.Compared with control check treatment with gravel content of 0%,soil water absorption rates in the treatments with gravel contents of 10%,20%,30%,40%,and 50%decreased by 11.47%,17.97%,25.24%,29.83%,and 42.45%,respectively.As the gravel content increased,inverse intake suction gradually increased,and shape coefficient,K_(s),θ_(s),andθ_(r)gradually decreased.For the same soil water content,soil water suction and K_(θ)gradually decreased with increasing gravel content.At the same soil water suction,C(h)decreased with increasing gravel content,and the water use efficiency worsened.Overall,the water holding capacity,hydraulic conductivity,and water use efficiency of stony soil in the eastern foothills of the Helan Mountains decreased with increasing gravel content.This study could provide data support for improving soil water use efficiency in the eastern foothills of the Helan Mountains and other similar rocky mountainous areas.
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.
