By studying typical "Top Eight Views" in cities like Xining,Lanzhou and Yinchuan in the upper reaches of the Yellow River,mountain and water landscapes in the study area were analyzed in terms of natural eco...By studying typical "Top Eight Views" in cities like Xining,Lanzhou and Yinchuan in the upper reaches of the Yellow River,mountain and water landscapes in the study area were analyzed in terms of natural ecology;bridges,canals,ferries,pavilions,mansions,towers,temples,historical sites,production and living landscapes were analyzed in terms of humanistic ecology.On this basis,"Top Eight Views" in the upper reaches of the Yellow River were compared and the following conclusions obtained:mountain landscapes were distributed in the whole region,waterscapes unevenly valued in different cities,bridges,canals and ferries mostly located in Ningxia,temples commonly found in all cities,garden arts introduced into cities,traditional cultures carried forward by historical relics.Then the relationship between "Top Eight Views" and regional eco-cultures was analyzed,and it was proposed that humanistic and cultural connotations of these "Top Eight Views" contributed a lot to beautifying urban environment,satisfying needs of the locals' spiritual life,carrying forward local history and culture,enriching urban cultural connotations,expanding living spaces of local residents and improving integrated functions of cities."Top Eight Views" culture complied with the construction gist of urban ecological cultures,and was of great referential value for the construction of urban ecological cultures in the upper reaches of the Yellow River,and also the healthy,scientific and sustainable development of local cities.展开更多
The upper reaches of the Yellow River in northeastern Tibetan Plateau are geohazards areas.The evolution of the Yellow River,chronology of some landslides,and spatiotemporal distribution characteristics of super large...The upper reaches of the Yellow River in northeastern Tibetan Plateau are geohazards areas.The evolution of the Yellow River,chronology of some landslides,and spatiotemporal distribution characteristics of super large scale and giant landslides within the region are summarized using paleoclimate evidence,and the relationship between the intensive landslide period and climatic changes since the Last Glacial period is analyzed.It is concluded that （1） Super large scale and giant landslides are distributed widely within the region,particularly in the Qunke-Jianzha basin.（2） The chronological sequence of landslides is established by dating the slip zones of landslides and analyzing the relations between landslides and their overlying or underlying loess formations.Five landslide development periods are determined：53-49 ka BP,33-24 ka BP,10-8 ka BP,5-3.5 ka BP,and the present.（3） These correspond closely to warm and wet periods during the last 100,000 years,i.e.,two weak paleosol development stages of Malan loess deposited during the last Glacial period in the Chinese loess Plateau,L1-4 and L1-2 that belong to the marine oxygen isotope stage 3,the last deglaeial period,the Holocene Optimum,and the modern global warming period.（4） Landslide triggers may be closely linked to warm and wet periods related to rapid climatic transitions.展开更多
Several argillaceous platforms lie along the Yellow River（YR） of the eastern Guide Basin, northeastern Tibetan Plateau, and their compositions, formation processes, and geomorphic evolution remain debated. Using fie...Several argillaceous platforms lie along the Yellow River（YR） of the eastern Guide Basin, northeastern Tibetan Plateau, and their compositions, formation processes, and geomorphic evolution remain debated. Using field survey data, sample testing, and high-resolution remote sensing images, the evolution of the Erlian mudflow fans are analyzed. The data show significant differences between fans on either side of the YR. On the right bank, fans are dilute debris flows consisting of sand and gravel. On the left bank, fans are viscosity mudflows consisting of red clay. The composition and formation processes of the left bank platforms indicate a rainfall-induced pluvial landscape. Fan evolution can be divided into two stages： early-stage fans pre-date 16 ka B.P., and formed during the last deglaciation; late-stage fans post-date 8 ka B.P.. Both stages were induced by climate change. The data indicate that during the Last Glacial Maximum, the northeastern Tibetan Plateau experienced a cold and humid climate characterized by high rainfall. From 16–8 ka, the YR cut through the Erlian early mudflow fan, resulting in extensive erosion. Since 8 ka, the river channel has migrated south by at least 1.25 km, and late stage mudflow fan formation has occurred.展开更多
As one of the most fragile alpine plateau and canyon areas in China,the upper reaches of the Yangtze River are the key areas of ecological construction in China.It is also a key area for poverty alleviation in the cou...As one of the most fragile alpine plateau and canyon areas in China,the upper reaches of the Yangtze River are the key areas of ecological construction in China.It is also a key area for poverty alleviation in the country.Therefore,it is necessary to take into account the dual goals of poverty reduction and ecological environment construction,and explore a win-win road of ecological construction and poverty alleviation in line with the reality of the upper reaches of the Yangtze River.Taking Xueshan Township,Luquan Yi and Miao Autonomous County,Yunnan Province,which is located in the poor mountainous area of the upper reaches of the Yangtze River as an example,based on many field investigations and existing investigation and statistical data,this paper analyzes the current situation and main problems of land use in Xueshan Township,and then puts forward measures and suggestions for rational utilization of land resources in Xueshan Township.This can provide a necessary reference for the next implementation of rural revitalization strategy and ecological construction.展开更多
Sediment discharge from the Yellow River originates mainly from the drainage area between Hekouzhen and Longmen, i.e., the Helong area. Spatial-temporal variations of the vegetation cover in this area during the 1981-...Sediment discharge from the Yellow River originates mainly from the drainage area between Hekouzhen and Longmen, i.e., the Helong area. Spatial-temporal variations of the vegetation cover in this area during the 1981-2007 period have been investigated using GIMMS and SPOT VGT NDVI data. We have also analyzed the interannual variations in vegetation cover and changes in annual runoff and sediment discharge, the consequences from precipitation change and the Grain for Green Project （GGP）. The results show that vegetation cover of the Helong area has increased during the 1981-2007 period. The northwestern part the Helong area, where the flat sandy lands are covered by grass, has experienced the largest increase. The region where the vegetation cover has declined is largely found in the southern and southeastern Helong area, which is a gullied hilly area or forested. Although precipitation was relatively low during the 1999-2007 period, the vegetation cover showed a significant increase in the Helong area, due to the implementation of the GGP. During this period, the most significant improvement in the vegetation cover occurred mainly in the gullied hilly areas of the Loess Plateau, such as the drainage basins of the Kuyehe and Tuweihe rivers and the middle and lower reaches of the Wudinghe and Yanhe rivers. A comparison of the average annual maximum NDVI between the earlier （1998-2002） stage and the next five years （2003-2007） of the GGP indicates that the areas with increases of 10% and 20% in NDVI account for 72.5% and 36.4% of the total area, respectively. Interannual variation of annual runoff and sediment discharge shows a declining trend, especially since the 1980s, when the decrease became very obvious. Compared with the 1950-1969 period, the average runoff during the 1980-2007 period was reduced by 34.8 × 10^8 m3 and the sediment discharge by 6.4 ×10^8 t, accounting for 49.4% and 64.9% of that in the 1950-1969 period, respectively. There is a positive correlation between the annual maximum NDVI and annual runoff and sediment discharge. This correlation was reversed since the implementation of the GGP in 1999 and vegetation cover in the He- long area has increased, associated with the decrease in runoff and sediment discharge. Less precipitation has been an important fac- tor driving the decrease in runoff and sediment discharge during 1999 2007. However, restoration and improvement of the vegetation cover may also have played a significant role in accelerating the decrease in annual runoff and sediment discharge by enhancing evapotranspiration and alleviating soil erosion.展开更多
There are seven steps of terrace both in the Guide basin and Gonghe basin along the Yellow River. More close to the source, less the steps of terrace. Three ancient terraces are found in Gonghe basin. The upper reache...There are seven steps of terrace both in the Guide basin and Gonghe basin along the Yellow River. More close to the source, less the steps of terrace. Three ancient terraces are found in Gonghe basin. The upper reaches of the Yellow River was joined up by a series of stream captures at different periods of time, the ancient Yellow River linked up the Gonghe basin and Guide basin at the end of the middle Pleistocene, the Longyangxia gorge developed around 60 Ka.B.P., and the gorge between Maqu and Tangnag developed around 20 Ka.B.P.展开更多
Landslide is a serious natural disaster next only to earthquake and flood,which will cause a great threat to people’s lives and property safety.The traditional research of landslide disaster based on experience-drive...Landslide is a serious natural disaster next only to earthquake and flood,which will cause a great threat to people’s lives and property safety.The traditional research of landslide disaster based on experience-driven or statistical model and its assessment results are subjective,difficult to quantify,and no pertinence.As a new research method for landslide susceptibility assessment,machine learning can greatly improve the landslide susceptibility model’s accuracy by constructing statistical models.Taking Western Henan for example,the study selected 16 landslide influencing factors such as topography,geological environment,hydrological conditions,and human activities,and 11 landslide factors with the most significant influence on the landslide were selected by the recursive feature elimination(RFE)method.Five machine learning methods[Support Vector Machines(SVM),Logistic Regression(LR),Random Forest(RF),Extreme Gradient Boosting(XGBoost),and Linear Discriminant Analysis(LDA)]were used to construct the spatial distribution model of landslide susceptibility.The models were evaluated by the receiver operating characteristic curve and statistical index.After analysis and comparison,the XGBoost model(AUC 0.8759)performed the best and was suitable for dealing with regression problems.The model had a high adaptability to landslide data.According to the landslide susceptibility map of the five models,the overall distribution can be observed.The extremely high and high susceptibility areas are distributed in the Funiu Mountain range in the southwest,the Xiaoshan Mountain range in the west,and the Yellow River Basin in the north.These areas have large terrain fluctuations,complicated geological structural environments and frequent human engineering activities.The extremely high and highly prone areas were 12043.3 km^(2)and 3087.45 km^(2),accounting for 47.61%and 12.20%of the total area of the study area,respectively.Our study reflects the distribution of landslide susceptibility in western Henan Province,which provides a scientific basis for regional disaster warning,prediction,and resource protection.The study has important practical significance for subsequent landslide disaster management.展开更多
Studies of the geomorphology and stratigraphy in the upper reaches of the Yellow River during the late Cenozoic demonstrate that the period of 30 - 3.4 Ma is characterized by a relatively stable tectonic setting, a pe...Studies of the geomorphology and stratigraphy in the upper reaches of the Yellow River during the late Cenozoic demonstrate that the period of 30 - 3.4 Ma is characterized by a relatively stable tectonic setting, a persistently hot climate and a wide distribution of inland basins. This long-term stable environment resulted in a planation surface, the main surface on the Qinghai-Xizang (Qingzang) Plateau, on which red earth crust and karst arc formed. Since 3.4 Ma, the Qingzang Plateau was 'uplifted as a whole massif, accompanied by the dissection and disintegration of the main surface, termination of deposition and deformation of stratigraphy in red basins, increasing relief and commencing accumulation of inland molasse formation mainly of conglomerate. Subsequent strong uplift of the Qingzang Plateau at 2.5 Ma and 1.7-1.66 Ma led to cormation of the basic geomorphological configuration of the Qingzang Plateau and occurrence of the Yellow River. These three strong uplifts of the Qingzang Plateau between 3.4 Ma and 1.7 -1.66 Ma was, therefore, named the Qingzang movement and divided correspondingly into three phases A. B and C. After the appearance of the Yellow River, the Qingzang Plateau continued uplifting intermittently, resulting in 8 valley terraces dated to 1.63. 1.5, 1.2. 0.8, 0.6, 0.15. 0.05. and 0.01 Ma. which also record the whole process of headward erosion of the Yellow River.展开更多
黄河上游是黄河流域重要的水源涵养区,径流占流域多年平均(1956—2000年)总径流的62%,降水变化不仅是水源的主要影响因素,也关系到涵养能力的变化。本文利用黄河上游43个气象站1960—2021年逐日降水系列数据,基于小波分析划分周期,采用M...黄河上游是黄河流域重要的水源涵养区,径流占流域多年平均(1956—2000年)总径流的62%,降水变化不仅是水源的主要影响因素,也关系到涵养能力的变化。本文利用黄河上游43个气象站1960—2021年逐日降水系列数据,基于小波分析划分周期,采用Mann-Kendall检验法、距平法、频率曲线法等对上游区降水变化进行分析,结果表明:(1)黄河上游降水可划分出1963—1981年、1981—1999年、1999—2018年三个明显的周期;(2)1960—2021年年降水量以4.9 mm 10a的趋势增加,三个周期时段内年降水量的倾向率分别为-0.9 mm 10a,-1.0 mm 10a,46mm 10a;(3)1960—2021年年降水量距平百分率在-15%~15%的正常年份占比74%,距平百分率在-30%~-15%的轻旱年份和15%~30%的轻涝年份分别占比15%和8%;距平百分率在30%~40%的中涝年份占3%,旱涝年份基本发生在1963—1981年、1999—2018年两个周期;(4)三个周期时段日降水量具有差异的主要是频率小于10%的降水,且随海拔变化有差异,表现为1999—2018年玛沁站25~45.4 mm d降水量比以往增强,1999—2018年临夏站20~50 mm d降水量比以往增强,1963—1981年乌审召站50~65 mm d降水量比以往增强。展开更多
基金Supported by Hebei Provincial Social Science Foudation " Ecological Environment and Urban Development in the Upper Reaches of the Yellow River (1368 - 1928) " (HB10GJ016) ~~
文摘By studying typical "Top Eight Views" in cities like Xining,Lanzhou and Yinchuan in the upper reaches of the Yellow River,mountain and water landscapes in the study area were analyzed in terms of natural ecology;bridges,canals,ferries,pavilions,mansions,towers,temples,historical sites,production and living landscapes were analyzed in terms of humanistic ecology.On this basis,"Top Eight Views" in the upper reaches of the Yellow River were compared and the following conclusions obtained:mountain landscapes were distributed in the whole region,waterscapes unevenly valued in different cities,bridges,canals and ferries mostly located in Ningxia,temples commonly found in all cities,garden arts introduced into cities,traditional cultures carried forward by historical relics.Then the relationship between "Top Eight Views" and regional eco-cultures was analyzed,and it was proposed that humanistic and cultural connotations of these "Top Eight Views" contributed a lot to beautifying urban environment,satisfying needs of the locals' spiritual life,carrying forward local history and culture,enriching urban cultural connotations,expanding living spaces of local residents and improving integrated functions of cities."Top Eight Views" culture complied with the construction gist of urban ecological cultures,and was of great referential value for the construction of urban ecological cultures in the upper reaches of the Yellow River,and also the healthy,scientific and sustainable development of local cities.
基金financially supported by the National Nature Science Foundation of China under Grant No. 41372333, 40802089, 41172158China Geological Survey (grant No. 1212011220123)
文摘The upper reaches of the Yellow River in northeastern Tibetan Plateau are geohazards areas.The evolution of the Yellow River,chronology of some landslides,and spatiotemporal distribution characteristics of super large scale and giant landslides within the region are summarized using paleoclimate evidence,and the relationship between the intensive landslide period and climatic changes since the Last Glacial period is analyzed.It is concluded that （1） Super large scale and giant landslides are distributed widely within the region,particularly in the Qunke-Jianzha basin.（2） The chronological sequence of landslides is established by dating the slip zones of landslides and analyzing the relations between landslides and their overlying or underlying loess formations.Five landslide development periods are determined：53-49 ka BP,33-24 ka BP,10-8 ka BP,5-3.5 ka BP,and the present.（3） These correspond closely to warm and wet periods during the last 100,000 years,i.e.,two weak paleosol development stages of Malan loess deposited during the last Glacial period in the Chinese loess Plateau,L1-4 and L1-2 that belong to the marine oxygen isotope stage 3,the last deglaeial period,the Holocene Optimum,and the modern global warming period.（4） Landslide triggers may be closely linked to warm and wet periods related to rapid climatic transitions.
基金financially supported by the National Nature Science Foundation of China under Grant No.41372333,41172158China Geological Survey(grant No.1212011220123)
文摘Several argillaceous platforms lie along the Yellow River（YR） of the eastern Guide Basin, northeastern Tibetan Plateau, and their compositions, formation processes, and geomorphic evolution remain debated. Using field survey data, sample testing, and high-resolution remote sensing images, the evolution of the Erlian mudflow fans are analyzed. The data show significant differences between fans on either side of the YR. On the right bank, fans are dilute debris flows consisting of sand and gravel. On the left bank, fans are viscosity mudflows consisting of red clay. The composition and formation processes of the left bank platforms indicate a rainfall-induced pluvial landscape. Fan evolution can be divided into two stages： early-stage fans pre-date 16 ka B.P., and formed during the last deglaciation; late-stage fans post-date 8 ka B.P.. Both stages were induced by climate change. The data indicate that during the Last Glacial Maximum, the northeastern Tibetan Plateau experienced a cold and humid climate characterized by high rainfall. From 16–8 ka, the YR cut through the Erlian early mudflow fan, resulting in extensive erosion. Since 8 ka, the river channel has migrated south by at least 1.25 km, and late stage mudflow fan formation has occurred.
文摘As one of the most fragile alpine plateau and canyon areas in China,the upper reaches of the Yangtze River are the key areas of ecological construction in China.It is also a key area for poverty alleviation in the country.Therefore,it is necessary to take into account the dual goals of poverty reduction and ecological environment construction,and explore a win-win road of ecological construction and poverty alleviation in line with the reality of the upper reaches of the Yangtze River.Taking Xueshan Township,Luquan Yi and Miao Autonomous County,Yunnan Province,which is located in the poor mountainous area of the upper reaches of the Yangtze River as an example,based on many field investigations and existing investigation and statistical data,this paper analyzes the current situation and main problems of land use in Xueshan Township,and then puts forward measures and suggestions for rational utilization of land resources in Xueshan Township.This can provide a necessary reference for the next implementation of rural revitalization strategy and ecological construction.
基金supported by Beijing Forestry University for Young Scientist and funded by the National Natural Science Foundation of China (Grant No.40871136)
文摘Sediment discharge from the Yellow River originates mainly from the drainage area between Hekouzhen and Longmen, i.e., the Helong area. Spatial-temporal variations of the vegetation cover in this area during the 1981-2007 period have been investigated using GIMMS and SPOT VGT NDVI data. We have also analyzed the interannual variations in vegetation cover and changes in annual runoff and sediment discharge, the consequences from precipitation change and the Grain for Green Project （GGP）. The results show that vegetation cover of the Helong area has increased during the 1981-2007 period. The northwestern part the Helong area, where the flat sandy lands are covered by grass, has experienced the largest increase. The region where the vegetation cover has declined is largely found in the southern and southeastern Helong area, which is a gullied hilly area or forested. Although precipitation was relatively low during the 1999-2007 period, the vegetation cover showed a significant increase in the Helong area, due to the implementation of the GGP. During this period, the most significant improvement in the vegetation cover occurred mainly in the gullied hilly areas of the Loess Plateau, such as the drainage basins of the Kuyehe and Tuweihe rivers and the middle and lower reaches of the Wudinghe and Yanhe rivers. A comparison of the average annual maximum NDVI between the earlier （1998-2002） stage and the next five years （2003-2007） of the GGP indicates that the areas with increases of 10% and 20% in NDVI account for 72.5% and 36.4% of the total area, respectively. Interannual variation of annual runoff and sediment discharge shows a declining trend, especially since the 1980s, when the decrease became very obvious. Compared with the 1950-1969 period, the average runoff during the 1980-2007 period was reduced by 34.8 × 10^8 m3 and the sediment discharge by 6.4 ×10^8 t, accounting for 49.4% and 64.9% of that in the 1950-1969 period, respectively. There is a positive correlation between the annual maximum NDVI and annual runoff and sediment discharge. This correlation was reversed since the implementation of the GGP in 1999 and vegetation cover in the He- long area has increased, associated with the decrease in runoff and sediment discharge. Less precipitation has been an important fac- tor driving the decrease in runoff and sediment discharge during 1999 2007. However, restoration and improvement of the vegetation cover may also have played a significant role in accelerating the decrease in annual runoff and sediment discharge by enhancing evapotranspiration and alleviating soil erosion.
文摘There are seven steps of terrace both in the Guide basin and Gonghe basin along the Yellow River. More close to the source, less the steps of terrace. Three ancient terraces are found in Gonghe basin. The upper reaches of the Yellow River was joined up by a series of stream captures at different periods of time, the ancient Yellow River linked up the Gonghe basin and Guide basin at the end of the middle Pleistocene, the Longyangxia gorge developed around 60 Ka.B.P., and the gorge between Maqu and Tangnag developed around 20 Ka.B.P.
基金This work was financially supported by National Natural Science Foundation of China(41972262)Hebei Natural Science Foundation for Excellent Young Scholars(D2020504032)+1 种基金Central Plains Science and technology innovation leader Project(214200510030)Key research and development Project of Henan province(221111321500).
文摘Landslide is a serious natural disaster next only to earthquake and flood,which will cause a great threat to people’s lives and property safety.The traditional research of landslide disaster based on experience-driven or statistical model and its assessment results are subjective,difficult to quantify,and no pertinence.As a new research method for landslide susceptibility assessment,machine learning can greatly improve the landslide susceptibility model’s accuracy by constructing statistical models.Taking Western Henan for example,the study selected 16 landslide influencing factors such as topography,geological environment,hydrological conditions,and human activities,and 11 landslide factors with the most significant influence on the landslide were selected by the recursive feature elimination(RFE)method.Five machine learning methods[Support Vector Machines(SVM),Logistic Regression(LR),Random Forest(RF),Extreme Gradient Boosting(XGBoost),and Linear Discriminant Analysis(LDA)]were used to construct the spatial distribution model of landslide susceptibility.The models were evaluated by the receiver operating characteristic curve and statistical index.After analysis and comparison,the XGBoost model(AUC 0.8759)performed the best and was suitable for dealing with regression problems.The model had a high adaptability to landslide data.According to the landslide susceptibility map of the five models,the overall distribution can be observed.The extremely high and high susceptibility areas are distributed in the Funiu Mountain range in the southwest,the Xiaoshan Mountain range in the west,and the Yellow River Basin in the north.These areas have large terrain fluctuations,complicated geological structural environments and frequent human engineering activities.The extremely high and highly prone areas were 12043.3 km^(2)and 3087.45 km^(2),accounting for 47.61%and 12.20%of the total area of the study area,respectively.Our study reflects the distribution of landslide susceptibility in western Henan Province,which provides a scientific basis for regional disaster warning,prediction,and resource protection.The study has important practical significance for subsequent landslide disaster management.
基金Project supported by the State Eighth Five-Year Project on Studies of Formation and Evolution of the Qingzang Plateau, Environmental Change and Ecological System.
文摘Studies of the geomorphology and stratigraphy in the upper reaches of the Yellow River during the late Cenozoic demonstrate that the period of 30 - 3.4 Ma is characterized by a relatively stable tectonic setting, a persistently hot climate and a wide distribution of inland basins. This long-term stable environment resulted in a planation surface, the main surface on the Qinghai-Xizang (Qingzang) Plateau, on which red earth crust and karst arc formed. Since 3.4 Ma, the Qingzang Plateau was 'uplifted as a whole massif, accompanied by the dissection and disintegration of the main surface, termination of deposition and deformation of stratigraphy in red basins, increasing relief and commencing accumulation of inland molasse formation mainly of conglomerate. Subsequent strong uplift of the Qingzang Plateau at 2.5 Ma and 1.7-1.66 Ma led to cormation of the basic geomorphological configuration of the Qingzang Plateau and occurrence of the Yellow River. These three strong uplifts of the Qingzang Plateau between 3.4 Ma and 1.7 -1.66 Ma was, therefore, named the Qingzang movement and divided correspondingly into three phases A. B and C. After the appearance of the Yellow River, the Qingzang Plateau continued uplifting intermittently, resulting in 8 valley terraces dated to 1.63. 1.5, 1.2. 0.8, 0.6, 0.15. 0.05. and 0.01 Ma. which also record the whole process of headward erosion of the Yellow River.
文摘黄河上游是黄河流域重要的水源涵养区,径流占流域多年平均(1956—2000年)总径流的62%,降水变化不仅是水源的主要影响因素,也关系到涵养能力的变化。本文利用黄河上游43个气象站1960—2021年逐日降水系列数据,基于小波分析划分周期,采用Mann-Kendall检验法、距平法、频率曲线法等对上游区降水变化进行分析,结果表明:(1)黄河上游降水可划分出1963—1981年、1981—1999年、1999—2018年三个明显的周期;(2)1960—2021年年降水量以4.9 mm 10a的趋势增加,三个周期时段内年降水量的倾向率分别为-0.9 mm 10a,-1.0 mm 10a,46mm 10a;(3)1960—2021年年降水量距平百分率在-15%~15%的正常年份占比74%,距平百分率在-30%~-15%的轻旱年份和15%~30%的轻涝年份分别占比15%和8%;距平百分率在30%~40%的中涝年份占3%,旱涝年份基本发生在1963—1981年、1999—2018年两个周期;(4)三个周期时段日降水量具有差异的主要是频率小于10%的降水,且随海拔变化有差异,表现为1999—2018年玛沁站25~45.4 mm d降水量比以往增强,1999—2018年临夏站20~50 mm d降水量比以往增强,1963—1981年乌审召站50~65 mm d降水量比以往增强。
