NCEP/NCAR reanalysis data and a 30-year precipitation dataset of observed daily rainfall from 109 gauge stations are utilized in this paper.Using the REOF we analyzed the spatial distribution of precipitation in the 1...NCEP/NCAR reanalysis data and a 30-year precipitation dataset of observed daily rainfall from 109 gauge stations are utilized in this paper.Using the REOF we analyzed the spatial distribution of precipitation in the 109 stations in the Yangtze River Basin in Meiyu periods from 1978 to 2007.The result showed that the spatial distribution of precipitation in the Yangtze River Basin can be divided into the south and north part.As a result,relationships between an atmospheric heating source(hereafter called <Q_1>) over the Asian region and the precipitation on the south and north side of Yangtze River in Meiyu periods were separately studied in this paper.The results are shown as follows.The flood/drought to the north of Yangtze River(NYR) was mainly related to the <Q_1> over the East Asia summer monsoon region:when the <Q_1> over the Philippines through Western Pacific and the south China was weakened(strengthened),it would probably result in the flood(drought) in NYR;and the precipitation on the south side of Yangtze River(SYR)was related to the <Q_1> over the east Asia and Indian summer monsoon region:when the <Q_1> over the areas from south China to the northern East China Sea and Yellow Sea and south-eastern Japan was strengthened(weakened),and the <Q_1> over the areas from the Bay of Bengal to south-eastern Tibetan Plateau was weakened(strengthened),it will lead to flood(drought) in SYR.展开更多
The Nokoue Lake is the largest lake of Benin Republic and it is also considered as one of the most productive lagoon ecosystems in West Africa. This productivity is decreasing and thus raises productivity issue for a ...The Nokoue Lake is the largest lake of Benin Republic and it is also considered as one of the most productive lagoon ecosystems in West Africa. This productivity is decreasing and thus raises productivity issue for a better management and conservation. Macroinvertebrate can be useful for this purpose. A study was conducted to assess the spatial variation of macroinvertebrates during high flood period. A total of 3892 macroinvertebrates of fresh and brackish water were sampled during the survey. Structural analysis of the macroinvertebrate community revealed that it was made up of 16 orders, 48 families and 66 genera dominated by Insecta compared to Mollusca, Crustacea and the Annelida. Insects were dominated by Diptera (Chironomus sp. and Tanytarsus sp.), Coleoptera (Dystiscidae) and accounted for 57.1% of the sampled population. Mollusca, Crustacea, Annelida and Arachnida were the following most abundant and represented 23.9%, 10.7%, 8.1% and 0.2% of the total population, respectively. The Evenness index of Pielou was higher on the Station 8 (0.91 - 0.97), close to Oueme River. However, no significant difference (p > 0.05) was observed neither between station nor between month on the Shannon-Wiener index (2.06 - 4.31), Simpson index (0.04 - 0.40) and the taxa number (10 - 27). Macroinvertebrate assemblages and composition were primarily due to changes in water quality dependent on hydroclimatic changes and probably to anthropogenic actions. This suggests the need for real investigation of the macroinvertebrate biological capacity when formulating conservation strategies for the Nokoue Lake.展开更多
[Objective] The research aimed to analyze temporal and spatial variation of strong precipitation caused flood and agricultural disaster loss in Huaihe River basin of Anhui Province during Meiyu period of 2007.[Method]...[Objective] The research aimed to analyze temporal and spatial variation of strong precipitation caused flood and agricultural disaster loss in Huaihe River basin of Anhui Province during Meiyu period of 2007.[Method] On the basis of rainfalls of each station in Huaihe River basin of Anhui,rainfall data during Meiyu period of 2007 and flood disaster data in the same period,the temporal and spatial distribution characteristics of strong precipitation caused flood during Meiyu period of 2007 and its harm on agriculture were analyzed.The variation rule,distribution characteristics of strong precipitation during Meiyu period in Huaihe River basin of Anhui and its relationship with agricultural disaster loss were discussed.[Result] During Meiyu period of 2007 in Huaihe River basin of Anhui,the rainstorm was more,and the rainfall was large.The precipitation variation showed 'three-peak' trend.Rainfall in Huaihe River basin during Meiyu period of 2007 was greatly more than that homochronously in Yangtze River basin.The rain area over 400.0 mm during Meiyu period mainly located in Huaihe River basin,and the rain area over 600.0 mm mainly located from area along Huaihe River to central Huaibei.The rainfall during Meiyu period gradually decreased toward south and north by the north bank of Huaihe River as the symmetry axis.The rainfall in area along Huaihe River showed wavy distribution in east-west direction.The flood disaster loss index and disaster area of crops in Huaihe River basin of Anhui both increased as rainfall in Meiyu period.[Conclusion] The research provided theoretical basis for flood prevention,disaster reduction and agricultural flood-avoiding development in Huaihe River basin.展开更多
Based on the thermodynamic characteristics of the summer monsoon and foe change of the lower layer wind fields, the relation between the early summer flood periods of southern China, Including the first flood period o...Based on the thermodynamic characteristics of the summer monsoon and foe change of the lower layer wind fields, the relation between the early summer flood periods of southern China, Including the first flood period of South China and the plum rains period of the middle-lower reaches of the Yangtze River and the activities of the summer monsoon is analysed. The establishment processes of the summer monsoon circulation of East Asia are investigated. It is shown that the beginning and ending of the flood periods are exactly in accordance with the arrival and departure of the fore boundary of the summer monsoon. The establishment process of the circulation from the very beginning of the arrival of the monsoon to the time of great prosperity of development are not the same for each year. They can be classified into four categories. Each category may have four or three stages. Besides, the structure of the summer monsoon regime of East Asia is not unitary. There exist four types of structure model of the monsoon regime of East Asia.展开更多
Based on the meteorological and geographic information data, with statistical method and the FloodArea model, the extreme daily rainfall of the 100-year return period in Hunhe River basin was established, through the ...Based on the meteorological and geographic information data, with statistical method and the FloodArea model, the extreme daily rainfall of the 100-year return period in Hunhe River basin was established, through the simulation of rainstorm and flood disaster, characteristics of flood depth in warning spot Cangshi village in the upstream of the river were analysed, and possible effect on community economy was also evaluated. Results showed that, the precipitation of 100-year return period occurred, the flood depth has been below 1.0 meter in the most areas of Hunhe River basin, the depth was between 1.0 meter and 2.5 meters in the part areas of Hunhe River basin, and the flood depth has been exceed 2.5 meters in a small part of Hunhe River basin. After the beginning of precipitation, the flood was concentrated in the upper reaches of the river. With the accumulation of precipitation and the passage of time, the flood pools into midstream and downstream. Precipitation lasted for 24 hours, the warning spot was flooded in the beginning of precipitation. With the accumulation of precipitation, water level of the river increases gradually. The depth of warning spot has passed 1.0 meter at the 07 time of the whole process, and the maximum value of flood depth at warning spot was 1.083 meters that occurred at the 19 time. The flood depth of warning spot decreased gradually after the precipitation stopping, and the depth has been below 0.2 meters, the flood of upstream ended. Up to the end of the upstream flood process, in the whole river, about one million five hundred and sixty thousand people were affected by flooding, and thirty-eight billion and two hundred million RMB of gross domestic product were lost, in addition, dry land and paddy field were affected greatly, but woodland and grassland were less affected.展开更多
It is very important to study the archaeological culture and origin of civilization in ancient China.The changes of the channels in the lower reaches of the Yellow River in the prehistoric period are part of the natur...It is very important to study the archaeological culture and origin of civilization in ancient China.The changes of the channels in the lower reaches of the Yellow River in the prehistoric period are part of the natural environmental background of the development of the ancient civilization in that area to be explored.This paper presents a series of legends,indications,scientific evidence,and macroscopic geographical background information of the evolution in the lower reaches of the Yellow River during the Longshan period.At first the river flowed from Northern Henan and Hebei to southwestern Shandong Province and Northern Anhui–Jiangsu provinces,and the mainstream of the Yellow River changed from the southeast to return to the north and flowed into the Bohai Sea in the late Longshan Period.During this period,floods were frequent.Various ethnic groups in the northern China plains suffered natural disasters and made great migrations which also contributed to the ethnic exchanges and integration.The people of the Central Plains made more dynamic adjustments in the relationship between mankind and the land by primitively escaping from the water and self–defensively controlling the rivers then to maintaining the local ecological environment by large–scale flood control measures,which promoted the settlement of Shandong,Henan,Jiangsu and Anhui provinces,the urban cultural development,and social evolution.Based on these events,the culture symbol of Dayu's Flood Control could be formed.展开更多
A brief introduction of a global atmospheric circulation model CCM3, which is used to simulate the precipitation in China, the height and the flow fields of the atmosphere, is made and the reliability of simulation is...A brief introduction of a global atmospheric circulation model CCM3, which is used to simulate the precipitation in China, the height and the flow fields of the atmosphere, is made and the reliability of simulation is analyzed. According to the negative correlation between rainfall in the first flood period in South China (FFSC) and sea surface temperature anomalies (SSTA) in a key region in western Pacific warm pool (West Region), two sensitive experiments are designed to investigate the effects of the latter on the former and the possible physical mechanism is discussed. It is found that in cold water (warm water) years, the rainfall in South China (SC) is far more (less) than normal, while the rainfall in the middle and low reaches of the Yangtze River is relatively less (more). The best correlative area of precipitation is located in Guangdong Province. It matches the diagnostic result well. The effect of SSTA on precipitation of FFSC is realized through the abnormality of atmospheric circulation and tested by a P-σnine-layer regional climate model. Moreover, the simulated result of the P-σmodel is basically coincident with that of the CCM3.展开更多
Yopougon, located in the western part of the Autonomous District of Abidjan, is the most heavily populated municipality in Côte d’Ivoire. However, this area is prone to floods and landslides during the rainy sea...Yopougon, located in the western part of the Autonomous District of Abidjan, is the most heavily populated municipality in Côte d’Ivoire. However, this area is prone to floods and landslides during the rainy season. The study aims to assess recent flood risks in the municipality of Yopougon of the Autonomous District of Abidjan. To achieve this objective, the study analyzed two types of data: daily rainfall from 1971 to 2022 and parameters derived from a Numerical Field and Altitude Model (NFAM). The study examined six rainfall parameters using statistical analysis and combined land use maps obtained from the NFAM of Yopougon. The results indicated that, in 67% of cases, extreme rainfall occurred mainly between week 3 of May and week 1 of July. The peak of extreme rainfall was observed in week 2 of June with 15% of cases. These are critical periods of flood risks in the Autonomous District of Abidjan, especially in Yopougon. In addition, there was variability of rainfall parameters in the Autonomous District of Abidjan. This was characterized by a drop of annual and seasonal rainfall, and an increase of numbers of rainy days. Flood risks in Yopougon are, therefore, due to the regular occurrence of rainy events. Recent floods in Yopougon were caused by normal rains ranging from 55 millimeters (mm) to 153 mm with a return period of less than five years. Abnormal heavy rains of a case study on June 20-21, 2022 in Yopougon were detected by outputs global climate models. Areas of very high risk of flood covered 18% of Yopougon, while 31% were at high risk. Climate information from this study can assist authorities to take in advance adaptation and management measures.展开更多
Before the peaceful liberation of Tibet in 1951, there were only about 80 kinds of journals on Tibetan studies. After 1952, the Central Government gave special support to the preservation and promotion of ethnic langu...Before the peaceful liberation of Tibet in 1951, there were only about 80 kinds of journals on Tibetan studies. After 1952, the Central Government gave special support to the preservation and promotion of ethnic languages. Newspapers, magazines and publishing houses mushroomed in Xinjiang, Inner Mongolia, Yunnan, Guangxi, Guizhou, Tibet, Qinghai, Gansu, Yanbian and other places where ethnic groups where living in compact communities. In this situation, journals on Tibetan studies developed in two stages : First Stage: 1950-1980. During this period, all the newspapers and journals in China carried news on economic and social development in Tibet. However, at the provincial level the only newspapers were the Qinqhai Tibetan Paper, Tibet Daily (Tibetan and Chinese editions) and Qinghai Daily, and at the regional level, among the very few newspapers available were the Gannan News, Aba News and Garze News. Magazines published during the period were equally sparse. They included Qinghai Lake, Zamqar, Qinghai Ethnic institute News, Hanhaichao, Snow Lotus, Tibet Science and T6chnology, Tibet Literary and Art, Tibetan Medicine, Tibet Ethnic institute News and Chinese Yaks. Second stage: 1981-1998. This period witnessed dramatic economic and social development. In this encouraging situation, the number of newspapers increased to more than 180 kinds in the Tibetan areas. Tibetan studies expanded in scope, covering politics, history, literature, arts, agriculture, livestock breeding, education, medicine, folklore, tourism, archaeology, finance, science and technology, and geology. The following is a brief introduction to the magazines published after the peaceful liberation of Tibet in 1951.展开更多
A strong rainfall during June 8-13,2010 in Zunyi City is comprehensively analyzed by several diagnosis methods,including space location,maximum value,history comparison,maximum value assumption and disaster influence ...A strong rainfall during June 8-13,2010 in Zunyi City is comprehensively analyzed by several diagnosis methods,including space location,maximum value,history comparison,maximum value assumption and disaster influence analysis.Results show that this time the successive heavy precipitation fall in the northeastern area of Zunyi City,which are Zheng’an,Daozheng and Wuchuan etc..There are in total of 4 times of heavy rainstorms,8 times of rainstorms and 8 times of heavy rains in 14 meteorological observatories of the entire city.In the whole 215 towns,the daily precipitation in 162 stations reaches rainstorm scale,of which 45 stations reaches heavy rainstorm scale.The 24 hours rainfall of the heavy rain in Wuchuan Maotian town reaches 288.6 mm and the maximum rainfall intensity is 90.2 mm.The total precipitation from 22:00 on 7th to 05:00 on 10th in Fenshui,Wuchuan reaches 423.0 mm.The 1 h maximum precipitation,daily maximum precipitation and the maximum precipitation in any 3 days all surpasses the rainstorm which occurs once in a hundred years.The heavy precipitation results in large range of water-logging and flooding;the water level of several rivers passes the dangerous or warning line.The damages and impacts of the disaster are also put forward in this paper.展开更多
With the precipitation data of 113 stations in East China during the last 50 years,the characteristics of the precipitation,including Precipitation Concentration Degree (PCD) and Precipitation Concentration Period (PC...With the precipitation data of 113 stations in East China during the last 50 years,the characteristics of the precipitation,including Precipitation Concentration Degree (PCD) and Precipitation Concentration Period (PCP) and their tendencies,are analyzed.The results show that the PCD in the northern part of the region is markedly higher than that in the southern part,but the PCP in the south is much earlier than that in the north by about one and a half months,which displays significant regional differences in precipitation.With the global warming,precipitation over East China shows an increasing tendency,but PCD displays a trend that is neither increasing nor decreasing.At the same time,the PCP is later than before,which can be mainly found in Jiangxi and southern Henan provinces.As a result,there are strong associations between the precipitation,PCD and PCP,which can be shown in the years with more precipitation,stronger PCD and later-than-usual PCP.In a word,the abnormal distribution of precipitation,PCP,and PCD over East China results in more extreme events of precipitation and more droughts and floods.展开更多
The oil production predicted by means of the conventional water-drive characteristic curve is typically affected by large deviations with respect to the actual value when the so-called high water-cut stage is entered....The oil production predicted by means of the conventional water-drive characteristic curve is typically affected by large deviations with respect to the actual value when the so-called high water-cut stage is entered.In order to solve this problem,a new characteristic relationship between the relative permeability ratio and the average water saturation is proposed.By comparing the outcomes of different matching methods,it is verified that it can well reflect the variation characteristics of the relative permeability ratio curve.Combining the new formula with a reservoir engineering method,two new formulas are derived for the water flooding characteristic curve in the high water-cut stage.Their practicability is verified by using the production data of Mawangmiao and Xijiakou blocks.The results show that the error between the predicted cumulative oil production and production data of the two new water drive characteristic curves is less than the error between the B-type water drive characteristic curve and the other two water drive characteristic curves.It is concluded that the two new characteristic curves can be used to estimate more accurately the recoverable reserves,the final recovery and to estimate the effects of water flooding.展开更多
Surat city, the commercial capital of Gujarat state, India is situated at latitude 21°06’ to 21°15’ N and longitude 72°45' to 72°54'E on the bank of river Tapi and is affected by flood on...Surat city, the commercial capital of Gujarat state, India is situated at latitude 21°06’ to 21°15’ N and longitude 72°45' to 72°54'E on the bank of river Tapi and is affected by flood once in every five years since last hundred years. Present study describes the application of HEC-RAS model with integration of GIS for delineation of flood plain. Digital Elevation Model (DEM) of Surat city is used as main input for flood inundation mapping. River section near Nehru Bridge is used as sample case to simulate flood flow. Discharges equal to food return period for 25 and 32 (worst flood year) have been used for investigation of flood scenario. Outcome of the research clearly indicates that most of the area of the Surat city is submerged for a depth of 2.5 to 4.0 m when the discharge released from Ukai dam equals to return period of 32 years (25768.09 Cumecs).展开更多
Documented materials, especially those about flooding catastrophe, are abundant comprehensive and well-preserved, which makes possible the systematical collection of materials about historical document about climate e...Documented materials, especially those about flooding catastrophe, are abundant comprehensive and well-preserved, which makes possible the systematical collection of materials about historical document about climate evolution in Changjiang (Yangtze) Delta region and its neighboring areas. We make good use of the exceptional information to discuss the genesis and principle of flooding in this region. Analysis shows that the main flooding periods in the studied region in the last 2000 years were the Western Jin Dynasty, Eastern Jin Dynasty, Northern and Southern Dynasties, Southern Song Dynasty, Yuan Dynasty, Ming Dynasty and Qing Dynasty. The periods with flooding peak values were the 4th century, 5th century, 7th century, 9th century, early 12th century, early 14th century, mid-15th century, and early 18th century A.D. Possibility of reappearance of flooding peak value in the early 21st century will be great, and the hazard prevention and the hazard reduction will be still hard.展开更多
Check dams have been widely used in China’s Loess Plateau region due to their effectiveness in erosion and flood control.However,the safety and stability of the check dam decrease with the operation process,which inc...Check dams have been widely used in China’s Loess Plateau region due to their effectiveness in erosion and flood control.However,the safety and stability of the check dam decrease with the operation process,which increases the probability of dam failure during flood events and threatens local residents’ life and property.Thus,this study simulated flood process of the check dam failure in the Wangmaogou watershed in Yulin City,Shaanxi Province,China,calculated different types of inundation losses based on the flood inundation area within the watershed,and determined the number of key flood protection check dams by classifying the flood risk levels of the check dams.The results showed that 5 dams in the watershed were subject to overtopping during different rainfall return periods,which was related to their flood discharge capacity.Dam failure flood process showed a rapid growth trend followed by slow decrease,and the time of flood peak advanced with increase in the return period.After harmonization of evaluation scales,the magnitude of flood inundation losses can be ranked as:economic losses(212.409 million yuan) > life losses(10.368 million yuan) > ecological losses(6.433 million yuan).The risk value for both individual dams and the whole dam system decreases as the return period increases.The number of key flood protection check dams in the Wangmaogou watershed was 2,3,3,3,4,and 5 for floods with return periods of 10,20,30,50,100,and 200 years,respectively.The results provided a theoretical basis for the safe operation and risk evaluation of check dams in the Loess Plateau Hills watershed.展开更多
基金National Natural Science Foundation of China(41275080)China Meteorological Administration Special Public Welfare Research Fund(GYHY201306022)Open Research Fund Program of Plateau Atmosphere and Environment Key Laboratory of Sichuan Province(PAEKL-2010-C3)
文摘NCEP/NCAR reanalysis data and a 30-year precipitation dataset of observed daily rainfall from 109 gauge stations are utilized in this paper.Using the REOF we analyzed the spatial distribution of precipitation in the 109 stations in the Yangtze River Basin in Meiyu periods from 1978 to 2007.The result showed that the spatial distribution of precipitation in the Yangtze River Basin can be divided into the south and north part.As a result,relationships between an atmospheric heating source(hereafter called <Q_1>) over the Asian region and the precipitation on the south and north side of Yangtze River in Meiyu periods were separately studied in this paper.The results are shown as follows.The flood/drought to the north of Yangtze River(NYR) was mainly related to the <Q_1> over the East Asia summer monsoon region:when the <Q_1> over the Philippines through Western Pacific and the south China was weakened(strengthened),it would probably result in the flood(drought) in NYR;and the precipitation on the south side of Yangtze River(SYR)was related to the <Q_1> over the east Asia and Indian summer monsoon region:when the <Q_1> over the areas from south China to the northern East China Sea and Yellow Sea and south-eastern Japan was strengthened(weakened),and the <Q_1> over the areas from the Bay of Bengal to south-eastern Tibetan Plateau was weakened(strengthened),it will lead to flood(drought) in SYR.
文摘The Nokoue Lake is the largest lake of Benin Republic and it is also considered as one of the most productive lagoon ecosystems in West Africa. This productivity is decreasing and thus raises productivity issue for a better management and conservation. Macroinvertebrate can be useful for this purpose. A study was conducted to assess the spatial variation of macroinvertebrates during high flood period. A total of 3892 macroinvertebrates of fresh and brackish water were sampled during the survey. Structural analysis of the macroinvertebrate community revealed that it was made up of 16 orders, 48 families and 66 genera dominated by Insecta compared to Mollusca, Crustacea and the Annelida. Insects were dominated by Diptera (Chironomus sp. and Tanytarsus sp.), Coleoptera (Dystiscidae) and accounted for 57.1% of the sampled population. Mollusca, Crustacea, Annelida and Arachnida were the following most abundant and represented 23.9%, 10.7%, 8.1% and 0.2% of the total population, respectively. The Evenness index of Pielou was higher on the Station 8 (0.91 - 0.97), close to Oueme River. However, no significant difference (p > 0.05) was observed neither between station nor between month on the Shannon-Wiener index (2.06 - 4.31), Simpson index (0.04 - 0.40) and the taxa number (10 - 27). Macroinvertebrate assemblages and composition were primarily due to changes in water quality dependent on hydroclimatic changes and probably to anthropogenic actions. This suggests the need for real investigation of the macroinvertebrate biological capacity when formulating conservation strategies for the Nokoue Lake.
基金Supported by Meteorological Open Research Fund of Huaihe River basin,China(HRM200805)Soft Science Research Plan of Ministry of Science and Technology,China(2007GXS3D087)
文摘[Objective] The research aimed to analyze temporal and spatial variation of strong precipitation caused flood and agricultural disaster loss in Huaihe River basin of Anhui Province during Meiyu period of 2007.[Method] On the basis of rainfalls of each station in Huaihe River basin of Anhui,rainfall data during Meiyu period of 2007 and flood disaster data in the same period,the temporal and spatial distribution characteristics of strong precipitation caused flood during Meiyu period of 2007 and its harm on agriculture were analyzed.The variation rule,distribution characteristics of strong precipitation during Meiyu period in Huaihe River basin of Anhui and its relationship with agricultural disaster loss were discussed.[Result] During Meiyu period of 2007 in Huaihe River basin of Anhui,the rainstorm was more,and the rainfall was large.The precipitation variation showed 'three-peak' trend.Rainfall in Huaihe River basin during Meiyu period of 2007 was greatly more than that homochronously in Yangtze River basin.The rain area over 400.0 mm during Meiyu period mainly located in Huaihe River basin,and the rain area over 600.0 mm mainly located from area along Huaihe River to central Huaibei.The rainfall during Meiyu period gradually decreased toward south and north by the north bank of Huaihe River as the symmetry axis.The rainfall in area along Huaihe River showed wavy distribution in east-west direction.The flood disaster loss index and disaster area of crops in Huaihe River basin of Anhui both increased as rainfall in Meiyu period.[Conclusion] The research provided theoretical basis for flood prevention,disaster reduction and agricultural flood-avoiding development in Huaihe River basin.
文摘Based on the thermodynamic characteristics of the summer monsoon and foe change of the lower layer wind fields, the relation between the early summer flood periods of southern China, Including the first flood period of South China and the plum rains period of the middle-lower reaches of the Yangtze River and the activities of the summer monsoon is analysed. The establishment processes of the summer monsoon circulation of East Asia are investigated. It is shown that the beginning and ending of the flood periods are exactly in accordance with the arrival and departure of the fore boundary of the summer monsoon. The establishment process of the circulation from the very beginning of the arrival of the monsoon to the time of great prosperity of development are not the same for each year. They can be classified into four categories. Each category may have four or three stages. Besides, the structure of the summer monsoon regime of East Asia is not unitary. There exist four types of structure model of the monsoon regime of East Asia.
文摘Based on the meteorological and geographic information data, with statistical method and the FloodArea model, the extreme daily rainfall of the 100-year return period in Hunhe River basin was established, through the simulation of rainstorm and flood disaster, characteristics of flood depth in warning spot Cangshi village in the upstream of the river were analysed, and possible effect on community economy was also evaluated. Results showed that, the precipitation of 100-year return period occurred, the flood depth has been below 1.0 meter in the most areas of Hunhe River basin, the depth was between 1.0 meter and 2.5 meters in the part areas of Hunhe River basin, and the flood depth has been exceed 2.5 meters in a small part of Hunhe River basin. After the beginning of precipitation, the flood was concentrated in the upper reaches of the river. With the accumulation of precipitation and the passage of time, the flood pools into midstream and downstream. Precipitation lasted for 24 hours, the warning spot was flooded in the beginning of precipitation. With the accumulation of precipitation, water level of the river increases gradually. The depth of warning spot has passed 1.0 meter at the 07 time of the whole process, and the maximum value of flood depth at warning spot was 1.083 meters that occurred at the 19 time. The flood depth of warning spot decreased gradually after the precipitation stopping, and the depth has been below 0.2 meters, the flood of upstream ended. Up to the end of the upstream flood process, in the whole river, about one million five hundred and sixty thousand people were affected by flooding, and thirty-eight billion and two hundred million RMB of gross domestic product were lost, in addition, dry land and paddy field were affected greatly, but woodland and grassland were less affected.
文摘It is very important to study the archaeological culture and origin of civilization in ancient China.The changes of the channels in the lower reaches of the Yellow River in the prehistoric period are part of the natural environmental background of the development of the ancient civilization in that area to be explored.This paper presents a series of legends,indications,scientific evidence,and macroscopic geographical background information of the evolution in the lower reaches of the Yellow River during the Longshan period.At first the river flowed from Northern Henan and Hebei to southwestern Shandong Province and Northern Anhui–Jiangsu provinces,and the mainstream of the Yellow River changed from the southeast to return to the north and flowed into the Bohai Sea in the late Longshan Period.During this period,floods were frequent.Various ethnic groups in the northern China plains suffered natural disasters and made great migrations which also contributed to the ethnic exchanges and integration.The people of the Central Plains made more dynamic adjustments in the relationship between mankind and the land by primitively escaping from the water and self–defensively controlling the rivers then to maintaining the local ecological environment by large–scale flood control measures,which promoted the settlement of Shandong,Henan,Jiangsu and Anhui provinces,the urban cultural development,and social evolution.Based on these events,the culture symbol of Dayu's Flood Control could be formed.
基金sponsored by the NSFC key project (40233037) and the "National Key Developing Programme for Basic Science" project (2004CB418300)
文摘A brief introduction of a global atmospheric circulation model CCM3, which is used to simulate the precipitation in China, the height and the flow fields of the atmosphere, is made and the reliability of simulation is analyzed. According to the negative correlation between rainfall in the first flood period in South China (FFSC) and sea surface temperature anomalies (SSTA) in a key region in western Pacific warm pool (West Region), two sensitive experiments are designed to investigate the effects of the latter on the former and the possible physical mechanism is discussed. It is found that in cold water (warm water) years, the rainfall in South China (SC) is far more (less) than normal, while the rainfall in the middle and low reaches of the Yangtze River is relatively less (more). The best correlative area of precipitation is located in Guangdong Province. It matches the diagnostic result well. The effect of SSTA on precipitation of FFSC is realized through the abnormality of atmospheric circulation and tested by a P-σnine-layer regional climate model. Moreover, the simulated result of the P-σmodel is basically coincident with that of the CCM3.
文摘Yopougon, located in the western part of the Autonomous District of Abidjan, is the most heavily populated municipality in Côte d’Ivoire. However, this area is prone to floods and landslides during the rainy season. The study aims to assess recent flood risks in the municipality of Yopougon of the Autonomous District of Abidjan. To achieve this objective, the study analyzed two types of data: daily rainfall from 1971 to 2022 and parameters derived from a Numerical Field and Altitude Model (NFAM). The study examined six rainfall parameters using statistical analysis and combined land use maps obtained from the NFAM of Yopougon. The results indicated that, in 67% of cases, extreme rainfall occurred mainly between week 3 of May and week 1 of July. The peak of extreme rainfall was observed in week 2 of June with 15% of cases. These are critical periods of flood risks in the Autonomous District of Abidjan, especially in Yopougon. In addition, there was variability of rainfall parameters in the Autonomous District of Abidjan. This was characterized by a drop of annual and seasonal rainfall, and an increase of numbers of rainy days. Flood risks in Yopougon are, therefore, due to the regular occurrence of rainy events. Recent floods in Yopougon were caused by normal rains ranging from 55 millimeters (mm) to 153 mm with a return period of less than five years. Abnormal heavy rains of a case study on June 20-21, 2022 in Yopougon were detected by outputs global climate models. Areas of very high risk of flood covered 18% of Yopougon, while 31% were at high risk. Climate information from this study can assist authorities to take in advance adaptation and management measures.
文摘Before the peaceful liberation of Tibet in 1951, there were only about 80 kinds of journals on Tibetan studies. After 1952, the Central Government gave special support to the preservation and promotion of ethnic languages. Newspapers, magazines and publishing houses mushroomed in Xinjiang, Inner Mongolia, Yunnan, Guangxi, Guizhou, Tibet, Qinghai, Gansu, Yanbian and other places where ethnic groups where living in compact communities. In this situation, journals on Tibetan studies developed in two stages : First Stage: 1950-1980. During this period, all the newspapers and journals in China carried news on economic and social development in Tibet. However, at the provincial level the only newspapers were the Qinqhai Tibetan Paper, Tibet Daily (Tibetan and Chinese editions) and Qinghai Daily, and at the regional level, among the very few newspapers available were the Gannan News, Aba News and Garze News. Magazines published during the period were equally sparse. They included Qinghai Lake, Zamqar, Qinghai Ethnic institute News, Hanhaichao, Snow Lotus, Tibet Science and T6chnology, Tibet Literary and Art, Tibetan Medicine, Tibet Ethnic institute News and Chinese Yaks. Second stage: 1981-1998. This period witnessed dramatic economic and social development. In this encouraging situation, the number of newspapers increased to more than 180 kinds in the Tibetan areas. Tibetan studies expanded in scope, covering politics, history, literature, arts, agriculture, livestock breeding, education, medicine, folklore, tourism, archaeology, finance, science and technology, and geology. The following is a brief introduction to the magazines published after the peaceful liberation of Tibet in 1951.
基金Supported by Zunyi City Science and Technology Program(Zunyi Science Agriculture No.200904)~~
文摘A strong rainfall during June 8-13,2010 in Zunyi City is comprehensively analyzed by several diagnosis methods,including space location,maximum value,history comparison,maximum value assumption and disaster influence analysis.Results show that this time the successive heavy precipitation fall in the northeastern area of Zunyi City,which are Zheng’an,Daozheng and Wuchuan etc..There are in total of 4 times of heavy rainstorms,8 times of rainstorms and 8 times of heavy rains in 14 meteorological observatories of the entire city.In the whole 215 towns,the daily precipitation in 162 stations reaches rainstorm scale,of which 45 stations reaches heavy rainstorm scale.The 24 hours rainfall of the heavy rain in Wuchuan Maotian town reaches 288.6 mm and the maximum rainfall intensity is 90.2 mm.The total precipitation from 22:00 on 7th to 05:00 on 10th in Fenshui,Wuchuan reaches 423.0 mm.The 1 h maximum precipitation,daily maximum precipitation and the maximum precipitation in any 3 days all surpasses the rainstorm which occurs once in a hundred years.The heavy precipitation results in large range of water-logging and flooding;the water level of several rivers passes the dangerous or warning line.The damages and impacts of the disaster are also put forward in this paper.
基金National Foundation for Outstanding Young Scientists (40825008)National Natural Science Foundation of China (40975020)Models and Technical Composites for Comprehensive Improvement of Ecological and Environmental Conditions in the Basin of Qinghai Lake (2007BAC30B05-4)
文摘With the precipitation data of 113 stations in East China during the last 50 years,the characteristics of the precipitation,including Precipitation Concentration Degree (PCD) and Precipitation Concentration Period (PCP) and their tendencies,are analyzed.The results show that the PCD in the northern part of the region is markedly higher than that in the southern part,but the PCP in the south is much earlier than that in the north by about one and a half months,which displays significant regional differences in precipitation.With the global warming,precipitation over East China shows an increasing tendency,but PCD displays a trend that is neither increasing nor decreasing.At the same time,the PCP is later than before,which can be mainly found in Jiangxi and southern Henan provinces.As a result,there are strong associations between the precipitation,PCD and PCP,which can be shown in the years with more precipitation,stronger PCD and later-than-usual PCP.In a word,the abnormal distribution of precipitation,PCP,and PCD over East China results in more extreme events of precipitation and more droughts and floods.
基金It is supported by the National Natural Science Foundation of China(No.51404037)supported by the Scientific and Technological Research Project of Sinopec Jianghan Oilfield Branch Company(No.ZKK0220006).
文摘The oil production predicted by means of the conventional water-drive characteristic curve is typically affected by large deviations with respect to the actual value when the so-called high water-cut stage is entered.In order to solve this problem,a new characteristic relationship between the relative permeability ratio and the average water saturation is proposed.By comparing the outcomes of different matching methods,it is verified that it can well reflect the variation characteristics of the relative permeability ratio curve.Combining the new formula with a reservoir engineering method,two new formulas are derived for the water flooding characteristic curve in the high water-cut stage.Their practicability is verified by using the production data of Mawangmiao and Xijiakou blocks.The results show that the error between the predicted cumulative oil production and production data of the two new water drive characteristic curves is less than the error between the B-type water drive characteristic curve and the other two water drive characteristic curves.It is concluded that the two new characteristic curves can be used to estimate more accurately the recoverable reserves,the final recovery and to estimate the effects of water flooding.
文摘Surat city, the commercial capital of Gujarat state, India is situated at latitude 21°06’ to 21°15’ N and longitude 72°45' to 72°54'E on the bank of river Tapi and is affected by flood once in every five years since last hundred years. Present study describes the application of HEC-RAS model with integration of GIS for delineation of flood plain. Digital Elevation Model (DEM) of Surat city is used as main input for flood inundation mapping. River section near Nehru Bridge is used as sample case to simulate flood flow. Discharges equal to food return period for 25 and 32 (worst flood year) have been used for investigation of flood scenario. Outcome of the research clearly indicates that most of the area of the Surat city is submerged for a depth of 2.5 to 4.0 m when the discharge released from Ukai dam equals to return period of 32 years (25768.09 Cumecs).
基金Under the auspices of the National Natural Science Foundation of China (No.40071083),"985 Project"for discipline construction
文摘Documented materials, especially those about flooding catastrophe, are abundant comprehensive and well-preserved, which makes possible the systematical collection of materials about historical document about climate evolution in Changjiang (Yangtze) Delta region and its neighboring areas. We make good use of the exceptional information to discuss the genesis and principle of flooding in this region. Analysis shows that the main flooding periods in the studied region in the last 2000 years were the Western Jin Dynasty, Eastern Jin Dynasty, Northern and Southern Dynasties, Southern Song Dynasty, Yuan Dynasty, Ming Dynasty and Qing Dynasty. The periods with flooding peak values were the 4th century, 5th century, 7th century, 9th century, early 12th century, early 14th century, mid-15th century, and early 18th century A.D. Possibility of reappearance of flooding peak value in the early 21st century will be great, and the hazard prevention and the hazard reduction will be still hard.
基金supported by the National Natural Science Foundation of China (Grant 42077073, 42373063, 42307447)Natural Science Basic Research Plan in Shaanxi Province of China (2022KJXX-62)。
文摘Check dams have been widely used in China’s Loess Plateau region due to their effectiveness in erosion and flood control.However,the safety and stability of the check dam decrease with the operation process,which increases the probability of dam failure during flood events and threatens local residents’ life and property.Thus,this study simulated flood process of the check dam failure in the Wangmaogou watershed in Yulin City,Shaanxi Province,China,calculated different types of inundation losses based on the flood inundation area within the watershed,and determined the number of key flood protection check dams by classifying the flood risk levels of the check dams.The results showed that 5 dams in the watershed were subject to overtopping during different rainfall return periods,which was related to their flood discharge capacity.Dam failure flood process showed a rapid growth trend followed by slow decrease,and the time of flood peak advanced with increase in the return period.After harmonization of evaluation scales,the magnitude of flood inundation losses can be ranked as:economic losses(212.409 million yuan) > life losses(10.368 million yuan) > ecological losses(6.433 million yuan).The risk value for both individual dams and the whole dam system decreases as the return period increases.The number of key flood protection check dams in the Wangmaogou watershed was 2,3,3,3,4,and 5 for floods with return periods of 10,20,30,50,100,and 200 years,respectively.The results provided a theoretical basis for the safe operation and risk evaluation of check dams in the Loess Plateau Hills watershed.