Runoff change and trend of the Naoli River Basin were studied through the time series analysis using the data from the hydrological and meteorological stations. Time series of hydrological data were from 1957 to 2009 ...Runoff change and trend of the Naoli River Basin were studied through the time series analysis using the data from the hydrological and meteorological stations. Time series of hydrological data were from 1957 to 2009 for Bao′an station, from 1955 to 2009 for Baoqing station, from 1956 to 2009 for Caizuizi station and from 1978 to 2009 for Hongqiling station. The influences of climate change and human activities on runoff change were investigated, and the causes of hydrological regime change were revealed. The seasonal runoff distribution of the Naoli River was extremely uneven, and the annual change was great. Overall, the annual runoff showed a significant decreasing trend. The annual runoff of Bao′an, Baoqing, and Caizuizi stations in 2009 decreased by 64.1%, 76.3%, and 84.3%, respectively, compared with their beginning data recorded. The wet and dry years of the Naoli River have changed in the study period. The frequency of wet year occurrence decreased and lasted longer, whereas that of dry year occurrence increased. The frequency of dry year occurrence increased from 25.0%-27.8% to 83.9%-87.5%. The years before the 1970s were mostly wet, whereas those after the 1970s were mostly dry. Precipitation reduction and land use changes contributed to the decrease in annual runoff. Rising temperature and water project construction have also contributed important effects on the runoff change of the Naoli River.展开更多
In this paper a geomorphic-centered system was proposed for classifying the wetlands on the Qinghai-Tibet Plateau in western China, where the flora comprises primarily grasses. Although the geomorphic properties (e.g....In this paper a geomorphic-centered system was proposed for classifying the wetlands on the Qinghai-Tibet Plateau in western China, where the flora comprises primarily grasses. Although the geomorphic properties (e.g., elevation and morphology) of wetlands form the primary criteria of classification, this system also takes hydrological processes into implicit consideration. It represents an improvement over the hydrogeomorphic perspective as the relative importance of the two components (wetness and landform) of wetlands is clearly differentiated. This geomorphic-centered perspective yields insights into the hydrogeomorphic dynamics of plateau wetlands while indicates their vulnerability to change and degradation indirectly. According to this geomorphic-centered perspective, all plateau wetlands fall into one of the seven types of alpine, piedmont, valley, terrace, floodplain, lacustrine, and riverine in three elevational categories of upland, midland, and lowland. Upland (alpine and piedmont) wetlands with the steepest topography are the most sensitive to change whereas midland (floodplain, terrace and valley) wetlands are less vulnerable to degradation owing to a high water reserve except terrace wetlands. They have a dry surface caused by infrequent hydrological replenishment owing to their higher elevation than the channel. Low lying (lacustrine and riverine) wetlands are the most resilient. The geomorphic-centered perspective developed in this paper provides a framework for improving recognition and management of wetlands on the Plateau. Resilient wetlands can be grazed more intensively without the risk of degradation. Fragile and vulnerable wetlands require careful managementto avoid degradation.展开更多
Decadal–centennial hydroclimate variability over eastern China during the last millennium is investigated using the product of Paleo Hydrodynamics Data Assimilation(PHYDA).Results reveal that the PHYDA depicts a more...Decadal–centennial hydroclimate variability over eastern China during the last millennium is investigated using the product of Paleo Hydrodynamics Data Assimilation(PHYDA).Results reveal that the PHYDA depicts a more homogeneous temporal pattern during the early part of the Little Ice Age with other reconstructions than those during the other periods,and could also identify the droughts of 1352–90 AD,1445–98 AD,1580–94 AD,and 1626–65 AD during this period.On centennial time scales,the PHYDA shows that the linkage between the Palmer drought severity index over eastern China and the Atlantic Multidecadal Oscillation(AMO)index is more marked than that with the El Niño–Southern Oscillation and the location of the intertropical convergence zone over the Asian–Australian monsoon area during the period after the 1350s.For the decadal droughts,the PHYDA suggests most of the drought events during the last millennium were linked to the El Niño–like mean states and the negative AMO states.展开更多
Dajingshan, Fenghuangshan and Meixi reservoirs are located in Zhuhai, a coastal city in southern China, and they function to supply drinking water to Zhulaai and Macao. For effectively supplying waster, they are hydro...Dajingshan, Fenghuangshan and Meixi reservoirs are located in Zhuhai, a coastal city in southern China, and they function to supply drinking water to Zhulaai and Macao. For effectively supplying waster, they are hydrologically connected and Dajingshan Reservoir first receives the water pumped from the fiver at Guangchang Pumping Station, and then feeds Fenghuangshan Reservoir, and the two well-connected reservoirs are mesotrophic. Meixi Reservoir is a small and oligotrophic water body and feeds Dajingshan Reservoir only in wet seasons when overflow occurs. Particulate organic matter (POM) was collected from three hydrologically connected water supply reservoirs, and seasonal variations of POM were ascertained from stable carbon and nitrogen isotopes in wet and dry seasons, and the effects of pumping water and reservoir connectivity on POM variations and composition were demonstrated by the relationships of the stable isotope ratios of POM. Seasonality and similarity of stable carbon and nitrogen isotopes of POM varied with hydrodynamics, connectivity and trophic states of the four studied water bodies. The two well- connected reservoirs displayed more similar seasonality for δ13CPOM than those between the fiver station and the two reservoirs. However, the opposite seasonality appeared for δSNPOM between the above waters and indicates different processes affecting the stable carbon and nitrogen isotopes ofPOM. δ13CPOM and δ15NPOM changed little between wet and dry seasons in Meixi Reservoir-a low productive and rain-driven system, suggesting little POM response to environmental changes in that water system. As expected, connectivity enhanced the similarity of the stable isotope ratios of POM between the water bodies.展开更多
This paper addresses the issue of Chinese students' oral English skills in talking about Chinese culture from the perspective of conversation analysis. To examine their performance in this regard, group discussion da...This paper addresses the issue of Chinese students' oral English skills in talking about Chinese culture from the perspective of conversation analysis. To examine their performance in this regard, group discussion data in the classroom were collected for analysis. Their oral skills in talking about Chinese New Year and Christmas, a Western festival, were analyzed and compared to determine their oral performance in describing their native culture. Comments by two native English speakers on the students' performance are used to complement the conversation analysis. The results indicate that, compared with their performance regarding Christmas, the students were able to express a wider range of cultural connotations about Chinese New Year in English, but they used significantly fewer correct culturally-loaded words and phrases, and switched to Chinese much more frequently, suggesting unsatisfactory oral skills in describing Chinese culture.展开更多
基金Under the auspices of National Natural Science Foundation of China (No. 40830535, 41001110, 41101092, 41171092)National Basic Research Program of China (No. 2010CB951304)the CAS/SAFEA (Chinese Academy of Sciences/State Administration of Foreign Experts Affairs) International Partnership Program for Creative Research Teams, Eleventh Five-Year' Key Technological Projects of Heilongjiang Province Farm Bureau (No. HNK10A-10-01, HNK10A-10-03)
文摘Runoff change and trend of the Naoli River Basin were studied through the time series analysis using the data from the hydrological and meteorological stations. Time series of hydrological data were from 1957 to 2009 for Bao′an station, from 1955 to 2009 for Baoqing station, from 1956 to 2009 for Caizuizi station and from 1978 to 2009 for Hongqiling station. The influences of climate change and human activities on runoff change were investigated, and the causes of hydrological regime change were revealed. The seasonal runoff distribution of the Naoli River was extremely uneven, and the annual change was great. Overall, the annual runoff showed a significant decreasing trend. The annual runoff of Bao′an, Baoqing, and Caizuizi stations in 2009 decreased by 64.1%, 76.3%, and 84.3%, respectively, compared with their beginning data recorded. The wet and dry years of the Naoli River have changed in the study period. The frequency of wet year occurrence decreased and lasted longer, whereas that of dry year occurrence increased. The frequency of dry year occurrence increased from 25.0%-27.8% to 83.9%-87.5%. The years before the 1970s were mostly wet, whereas those after the 1970s were mostly dry. Precipitation reduction and land use changes contributed to the decrease in annual runoff. Rising temperature and water project construction have also contributed important effects on the runoff change of the Naoli River.
基金supported by Program of International S&T Cooperation,the Ministry of Science and Technology of the People's Republic of China(Grant No.2011DFA20820)International Science&Technology Cooperation Program of China,MOST(Grant No.2011DFG93160)+1 种基金the Qinghai Science and Technology Department(Grant No.2009-J-806)Department of International Exchange&Cooperation of the Ministry of Education(Grant Nos.2009-1599,2010-1595)
文摘In this paper a geomorphic-centered system was proposed for classifying the wetlands on the Qinghai-Tibet Plateau in western China, where the flora comprises primarily grasses. Although the geomorphic properties (e.g., elevation and morphology) of wetlands form the primary criteria of classification, this system also takes hydrological processes into implicit consideration. It represents an improvement over the hydrogeomorphic perspective as the relative importance of the two components (wetness and landform) of wetlands is clearly differentiated. This geomorphic-centered perspective yields insights into the hydrogeomorphic dynamics of plateau wetlands while indicates their vulnerability to change and degradation indirectly. According to this geomorphic-centered perspective, all plateau wetlands fall into one of the seven types of alpine, piedmont, valley, terrace, floodplain, lacustrine, and riverine in three elevational categories of upland, midland, and lowland. Upland (alpine and piedmont) wetlands with the steepest topography are the most sensitive to change whereas midland (floodplain, terrace and valley) wetlands are less vulnerable to degradation owing to a high water reserve except terrace wetlands. They have a dry surface caused by infrequent hydrological replenishment owing to their higher elevation than the channel. Low lying (lacustrine and riverine) wetlands are the most resilient. The geomorphic-centered perspective developed in this paper provides a framework for improving recognition and management of wetlands on the Plateau. Resilient wetlands can be grazed more intensively without the risk of degradation. Fragile and vulnerable wetlands require careful managementto avoid degradation.
基金This work was supported by the National Natural Science Foundation of China[grant number 41605046].
文摘Decadal–centennial hydroclimate variability over eastern China during the last millennium is investigated using the product of Paleo Hydrodynamics Data Assimilation(PHYDA).Results reveal that the PHYDA depicts a more homogeneous temporal pattern during the early part of the Little Ice Age with other reconstructions than those during the other periods,and could also identify the droughts of 1352–90 AD,1445–98 AD,1580–94 AD,and 1626–65 AD during this period.On centennial time scales,the PHYDA shows that the linkage between the Palmer drought severity index over eastern China and the Atlantic Multidecadal Oscillation(AMO)index is more marked than that with the El Niño–Southern Oscillation and the location of the intertropical convergence zone over the Asian–Australian monsoon area during the period after the 1350s.For the decadal droughts,the PHYDA suggests most of the drought events during the last millennium were linked to the El Niño–like mean states and the negative AMO states.
基金Supported by the National Natural Science Foundation of China(No.31170436)the Science and Technology Project of Guangdong Province(No.2013B080500022)
文摘Dajingshan, Fenghuangshan and Meixi reservoirs are located in Zhuhai, a coastal city in southern China, and they function to supply drinking water to Zhulaai and Macao. For effectively supplying waster, they are hydrologically connected and Dajingshan Reservoir first receives the water pumped from the fiver at Guangchang Pumping Station, and then feeds Fenghuangshan Reservoir, and the two well-connected reservoirs are mesotrophic. Meixi Reservoir is a small and oligotrophic water body and feeds Dajingshan Reservoir only in wet seasons when overflow occurs. Particulate organic matter (POM) was collected from three hydrologically connected water supply reservoirs, and seasonal variations of POM were ascertained from stable carbon and nitrogen isotopes in wet and dry seasons, and the effects of pumping water and reservoir connectivity on POM variations and composition were demonstrated by the relationships of the stable isotope ratios of POM. Seasonality and similarity of stable carbon and nitrogen isotopes of POM varied with hydrodynamics, connectivity and trophic states of the four studied water bodies. The two well- connected reservoirs displayed more similar seasonality for δ13CPOM than those between the fiver station and the two reservoirs. However, the opposite seasonality appeared for δSNPOM between the above waters and indicates different processes affecting the stable carbon and nitrogen isotopes ofPOM. δ13CPOM and δ15NPOM changed little between wet and dry seasons in Meixi Reservoir-a low productive and rain-driven system, suggesting little POM response to environmental changes in that water system. As expected, connectivity enhanced the similarity of the stable isotope ratios of POM between the water bodies.
文摘This paper addresses the issue of Chinese students' oral English skills in talking about Chinese culture from the perspective of conversation analysis. To examine their performance in this regard, group discussion data in the classroom were collected for analysis. Their oral skills in talking about Chinese New Year and Christmas, a Western festival, were analyzed and compared to determine their oral performance in describing their native culture. Comments by two native English speakers on the students' performance are used to complement the conversation analysis. The results indicate that, compared with their performance regarding Christmas, the students were able to express a wider range of cultural connotations about Chinese New Year in English, but they used significantly fewer correct culturally-loaded words and phrases, and switched to Chinese much more frequently, suggesting unsatisfactory oral skills in describing Chinese culture.