[Objective] This study aimed to investigate the driving mechanism of eco- logical security in vulnerable areas in mountain and plain. [Method] The ecological security evaluation index system of Lincheng County was est...[Objective] This study aimed to investigate the driving mechanism of eco- logical security in vulnerable areas in mountain and plain. [Method] The ecological security evaluation index system of Lincheng County was established using PSR model. Driving mechanism was analyzed in total system and subsystems respectively by the principal components. The ecological safety driving factor was calculated through the total system and subsystem respectively. And the intersection was adopt- ed as dominant driving factor. [Result] A total of 10 indices including density index of rivers, land degradation index, farmland drought and flood insurance yield, human in- terference index, population density, the natural population growth rate, per capita GDP, the R&D funds spending accounts for the proportion of GDP, laborer by edu- cation degree and three industry accounted for the proportion of GDP, are the domi- nant driving factors of the regional ecological security. [Conclusion] This study will pro- vide reasonable and feasible advice for the benign development of the area.展开更多
Methods of participatory rural appraisal and mathematical statistics were adopted to study livelihood diversification, livelihood strategy and farmland use of the four types of farmers in Xinping County of Yuanjiang d...Methods of participatory rural appraisal and mathematical statistics were adopted to study livelihood diversification, livelihood strategy and farmland use of the four types of farmers in Xinping County of Yuanjiang dry-hot valley with field survey data. The results showed as follows: firstly, as farmers are transforming from pure agriculture to non-agriculture, their agricultural livelihood diversification index will decrease, while non-agricultural livelihood diversification index will increase. In term of livelihood activities, pure agricultural farmers are exclusively engaged in agricultural activities, agricultural-dominant and non-agricultural-dominant farmers are engaged in both agricultural and non-agricultural ones, while non-agricultural farmers are basically engaged in off-farm activities. Secondly, as for crops planted, pure agricultural and agricultural-dominant farmers tend to choose those crops with more investment,shorter growth period and higher value, meanwhile non-agricultural-dominant farmers tend to choose crops with less investment, simpler management and longer growth period. Thirdly, to cope with current problems in farming, pure agricultural farmers will adopt measures such as changing planting structure, maintaining or expanding planting scale, increasing planting investment and renting in more land to promote the development of farming; agriculture-dominant farmers will adopt measures such as changing planting structure, reducing planting scale, maintaining planting investment, renting in and taking back the leased land as well as engaging in non-agricultural activities to overcome the difficulties faced; while non-agricultural-dominant farmers will adopt measures such as reducing both planting scale and investment,changing planting structure and engaging in farmland transfer as well as various offfarm activities to avoid livelihood risks.展开更多
Based on the decoupiing theory and method, an indicator system was built for the relation between economic development level and resource and environment carrying capacity. And the study was carried out on decoupling ...Based on the decoupiing theory and method, an indicator system was built for the relation between economic development level and resource and environment carrying capacity. And the study was carried out on decoupling degree and temporal changes of economic development level and resource and environment carrying ca- pacity in the central area of Yunnan Province. Results indicated that (i) the economic development level and resource and environment carrying capacity in the central area of Yunnan Province mainly experienced strong decoupling, weak decoupling, and ex- pansive negative coupling, and in general it was strong decoupling, and it took on re- verse "N" in temporal changes. (ii) Change rate of economic development level in the central area of Yunnan Province was greater than zero, but the amplitude of change was not large, while the change rate of resource and environment carrying capacity was negative in 2007-2008, and it was positive in the rest years; from 2007, it took on gradual expansion trend, and scissors difference gradually increased after experi- encing reverse "V" change. (iii) The strong decoupling was the main situation and it reached the peak value in T5 period and T6 pedod.展开更多
This paper aims to carry out the preliminary study on the zoogeographic distributions of 166 species within Gnaphosidae by clustering method,and analyze and compare the similarities of 15 subregions in seven zoogeogra...This paper aims to carry out the preliminary study on the zoogeographic distributions of 166 species within Gnaphosidae by clustering method,and analyze and compare the similarities of 15 subregions in seven zoogeographic regions in China.The results suggested that the division of Northern China was coincident with the distribution pattern of Chinese ground spiders,but there was subregion recombination between the other regions.There was aggregation between Da Hinggan Mountains subregion in the Northeast,east plain subregion in Mengxin area and west hungriness subregion,between Tianshan mountainous subregion in Mengxin area,Qiangtang altiplano subregion and the southwest mountainous region subregion in Southwest,and between east hill plain subregion in central China,west mountainous region altiplano subregion,Min and Guang coastal subregion in south of China and south Dian mountainous region subregion.The other two subregions in the Northeast formed a region.Qinghai and south Xizang subregion in Qinghai-Xizang Region formed a branch independently.展开更多
To improve the understandings on regional climatic effects of past human-induced land cover changes,the surface albedo changes caused by conversions from natural vegetation to cropland were estimated across northeaste...To improve the understandings on regional climatic effects of past human-induced land cover changes,the surface albedo changes caused by conversions from natural vegetation to cropland were estimated across northeastern China over the last 300 years,and its climatic effects were simulated by using the Weather Research and Forecasting (WRF) model.Essential natural vegetation records compiled from historical documents and regional optimal surface albedo dataset were used.The results show that the surface albedo decreased by 0.01-0.03 due to conversions from grassland to cropland in the Northeast China Plain and it increased by 0.005-0.015 due to conversions from forests to cropland in the surrounding mountains.As a consequence,in the Northeast China Plain,the surface net radiation increased by 4-8 W/m 2,2-5 W/m 2,and 1-3 W/m 2,and the climate was therefore warmed by 0.1℃-0.2℃、0.1℃-0.2℃、 0.1℃-0.3 ℃ in the spring,autumn and winter,respectively.In the surrounding mountain area,the net radiation decreased by less than 1.5 W/m 2,and the climate was therefore cooled too slight to be detected.In summer,effects of surface albedo changes on climate were closely associated with moisture dynamics,such as evapotranspiration and cloud,instead of being merely determined by surface radiation budget.The simulated summer climatic effects have large uncertainties.These findings demonstrate that surface albedo changes resulted in warming climate effects in the non-rainy seasons in Northeast China Plain through surface radiation processes while the climatic effects in summer could hardly be concluded so far.展开更多
An ocean reanalysis system for the joining area of Asia and Indian-Pacific Ocean (AIPO) has been developed and is currently delivering reanalysis data sets for study on the air-sea interaction over AIPO and its climat...An ocean reanalysis system for the joining area of Asia and Indian-Pacific Ocean (AIPO) has been developed and is currently delivering reanalysis data sets for study on the air-sea interaction over AIPO and its climate variation over China in the inter-annual time scale.This system consists of a nested ocean model forced by atmospheric reanalysis,an ensemble-based multivariate ocean data assimilation system and various ocean observations.The following report describes the main components of the data assimilation system in detail.The system adopts an ensemble optimal interpolation scheme that uses a seasonal update from a free running model to estimate the background error covariance matrix.In view of the systematic biases in some observation systems,some treatments were performed on the observations before the assimilation.A coarse resolution reanalysis dataset from the system is preliminarily evaluated to demonstrate the performance of the system for the period 1992 to 2006 by comparing this dataset with other observations or reanalysis data.展开更多
The skewness of subsurface temperature anomaly in the equatorial Pacific Ocean shows a significant asymmetry between the east and west. A positive temperature skewness appears in the equatorial eastern Pacific, while ...The skewness of subsurface temperature anomaly in the equatorial Pacific Ocean shows a significant asymmetry between the east and west. A positive temperature skewness appears in the equatorial eastern Pacific, while the temperature skewness in the western and central Pacific is primarily negative. There is also an asymmetry of the temperature skewness above and below the climatological mean therrnocline in the central and western Pacific. A positive skewness appears below the thermocline, but the skewness is negative above the thermocline. The distinctive vertical asymmetry of the temperature skewness is argued to be attributed to the asymmetric temperature response to upward and downward thermocline displacement in the presence of the observed upper-ocean vertical thermal structure. Because of positive (negative) second derivative of temperature with respect to depth below (above) the thermocline, an upward and a downward shift of the thermocline with equal displacement would lead to a negative temperature skewness above the thermocline but a positive skewness below the thermocline. In the far eastern equatorial Pacific, the thermocline is close to the base of the mixed layer, the shape of the upper-ocean vertical temperature profile cannot be kept. Positive skewness appears in both below the thermocline and above the thermocline in the far eastern basin. Over the central and eastern Pacific, the anomalies of the subsurface waters tend to entrain into the surface mixed layer (by climatological mean upwelling) and then affect the SST. Hence, the positive (negative) subsurface skewness in the far eastern (central) Pacific may favor positive (negative) SST skewness, which is consistent with the observational fact that more La Nina (EI Nino) occur in the central (eastern) Pacific. The present result implies a possible new paradigm for EI Nino and La Nina amplitude asymmetry in the eastern Pacific.展开更多
Maize (Zea mays L.), a staple crop grown from June to September during the rainy season on the North China Plain,is usually inter-planted in winter wheat (Triticum aestivum L.) fields about one week before harvesting ...Maize (Zea mays L.), a staple crop grown from June to September during the rainy season on the North China Plain,is usually inter-planted in winter wheat (Triticum aestivum L.) fields about one week before harvesting of the winterwheat. In order to improve irrigation efficiency in this region of serious water shortage, field studies in 1999 and 2001, twodry seasons with less than average seasonal rainfall, were conducted with up to five irrigation applications to determineevapotranspiration, calculate the crop coefficient, and optimize the irrigation schedule with maize under mulch, as well asto establish the effects of irrigation timing and the number of applications on grain yield and water use efficiency (WUE)of maize. Results showed that with grain production at about 8 000 kg ha-1 the total evapotranspiration and WUE ofirrigated maize under mulch were about 380-400 mm and 2.0-2.2 kg m-3, respectively. Also in 2001 WUE of maizewith mulch for the treatment with three irrigations was 11.8% better than that without mulch. In the 1999 and 2001seasons, maize yield significantly improved (P = 0.05) with four irrigation applications, however, further increases werenot significant. At the same time there were no significant differences for WUE with two to four irrigation applications.In the 2001 season mulch lead to a decrease of 50 mm in the total soil evaporation, and the maize crop coefficient undermulch varied between 0.3-1.3 with a seasonal average of 1.0.展开更多
基金Supported by Hebei Provincial Natural Science Fund for Youth (D2010001566)Projects of Hebei Academy of Science and Technology (12116, 13140)Hebei Key Technology Research and Development Program (11237126D)~~
文摘[Objective] This study aimed to investigate the driving mechanism of eco- logical security in vulnerable areas in mountain and plain. [Method] The ecological security evaluation index system of Lincheng County was established using PSR model. Driving mechanism was analyzed in total system and subsystems respectively by the principal components. The ecological safety driving factor was calculated through the total system and subsystem respectively. And the intersection was adopt- ed as dominant driving factor. [Result] A total of 10 indices including density index of rivers, land degradation index, farmland drought and flood insurance yield, human in- terference index, population density, the natural population growth rate, per capita GDP, the R&D funds spending accounts for the proportion of GDP, laborer by edu- cation degree and three industry accounted for the proportion of GDP, are the domi- nant driving factors of the regional ecological security. [Conclusion] This study will pro- vide reasonable and feasible advice for the benign development of the area.
基金Supported by the National Social Science Foundation(13BMZ059)the Training Program for Young and Middle-aged Backbone Teachers of Yunnan University(XT412003)~~
文摘Methods of participatory rural appraisal and mathematical statistics were adopted to study livelihood diversification, livelihood strategy and farmland use of the four types of farmers in Xinping County of Yuanjiang dry-hot valley with field survey data. The results showed as follows: firstly, as farmers are transforming from pure agriculture to non-agriculture, their agricultural livelihood diversification index will decrease, while non-agricultural livelihood diversification index will increase. In term of livelihood activities, pure agricultural farmers are exclusively engaged in agricultural activities, agricultural-dominant and non-agricultural-dominant farmers are engaged in both agricultural and non-agricultural ones, while non-agricultural farmers are basically engaged in off-farm activities. Secondly, as for crops planted, pure agricultural and agricultural-dominant farmers tend to choose those crops with more investment,shorter growth period and higher value, meanwhile non-agricultural-dominant farmers tend to choose crops with less investment, simpler management and longer growth period. Thirdly, to cope with current problems in farming, pure agricultural farmers will adopt measures such as changing planting structure, maintaining or expanding planting scale, increasing planting investment and renting in more land to promote the development of farming; agriculture-dominant farmers will adopt measures such as changing planting structure, reducing planting scale, maintaining planting investment, renting in and taking back the leased land as well as engaging in non-agricultural activities to overcome the difficulties faced; while non-agricultural-dominant farmers will adopt measures such as reducing both planting scale and investment,changing planting structure and engaging in farmland transfer as well as various offfarm activities to avoid livelihood risks.
基金Supported by Scientific Research Foundation of Yunnan Provincial Department of Education(2015J088)~~
文摘Based on the decoupiing theory and method, an indicator system was built for the relation between economic development level and resource and environment carrying capacity. And the study was carried out on decoupling degree and temporal changes of economic development level and resource and environment carrying ca- pacity in the central area of Yunnan Province. Results indicated that (i) the economic development level and resource and environment carrying capacity in the central area of Yunnan Province mainly experienced strong decoupling, weak decoupling, and ex- pansive negative coupling, and in general it was strong decoupling, and it took on re- verse "N" in temporal changes. (ii) Change rate of economic development level in the central area of Yunnan Province was greater than zero, but the amplitude of change was not large, while the change rate of resource and environment carrying capacity was negative in 2007-2008, and it was positive in the rest years; from 2007, it took on gradual expansion trend, and scissors difference gradually increased after experi- encing reverse "V" change. (iii) The strong decoupling was the main situation and it reached the peak value in T5 period and T6 pedod.
文摘This paper aims to carry out the preliminary study on the zoogeographic distributions of 166 species within Gnaphosidae by clustering method,and analyze and compare the similarities of 15 subregions in seven zoogeographic regions in China.The results suggested that the division of Northern China was coincident with the distribution pattern of Chinese ground spiders,but there was subregion recombination between the other regions.There was aggregation between Da Hinggan Mountains subregion in the Northeast,east plain subregion in Mengxin area and west hungriness subregion,between Tianshan mountainous subregion in Mengxin area,Qiangtang altiplano subregion and the southwest mountainous region subregion in Southwest,and between east hill plain subregion in central China,west mountainous region altiplano subregion,Min and Guang coastal subregion in south of China and south Dian mountainous region subregion.The other two subregions in the Northeast formed a region.Qinghai and south Xizang subregion in Qinghai-Xizang Region formed a branch independently.
基金Under the auspices of National Natural Science Foundation of China(No.41001122)China Global Change Research Program(No.2010CB950102,2010CB950903)State-Sponsored Study Abroad Programs from China Scholarship Council(No.2007U21061)
文摘To improve the understandings on regional climatic effects of past human-induced land cover changes,the surface albedo changes caused by conversions from natural vegetation to cropland were estimated across northeastern China over the last 300 years,and its climatic effects were simulated by using the Weather Research and Forecasting (WRF) model.Essential natural vegetation records compiled from historical documents and regional optimal surface albedo dataset were used.The results show that the surface albedo decreased by 0.01-0.03 due to conversions from grassland to cropland in the Northeast China Plain and it increased by 0.005-0.015 due to conversions from forests to cropland in the surrounding mountains.As a consequence,in the Northeast China Plain,the surface net radiation increased by 4-8 W/m 2,2-5 W/m 2,and 1-3 W/m 2,and the climate was therefore warmed by 0.1℃-0.2℃、0.1℃-0.2℃、 0.1℃-0.3 ℃ in the spring,autumn and winter,respectively.In the surrounding mountain area,the net radiation decreased by less than 1.5 W/m 2,and the climate was therefore cooled too slight to be detected.In summer,effects of surface albedo changes on climate were closely associated with moisture dynamics,such as evapotranspiration and cloud,instead of being merely determined by surface radiation budget.The simulated summer climatic effects have large uncertainties.These findings demonstrate that surface albedo changes resulted in warming climate effects in the non-rainy seasons in Northeast China Plain through surface radiation processes while the climatic effects in summer could hardly be concluded so far.
基金supported by the Chinese Academy of Sciences (Grant No. KZCX2-YW-202)the 973 Pro-gram (Grant No. 2006CB403606),the 863 Program (Grant No.2009AA12Z138)the National Natural Science Foundation of China (Grant Nos. 40606008,40437017,and 40221503)
文摘An ocean reanalysis system for the joining area of Asia and Indian-Pacific Ocean (AIPO) has been developed and is currently delivering reanalysis data sets for study on the air-sea interaction over AIPO and its climate variation over China in the inter-annual time scale.This system consists of a nested ocean model forced by atmospheric reanalysis,an ensemble-based multivariate ocean data assimilation system and various ocean observations.The following report describes the main components of the data assimilation system in detail.The system adopts an ensemble optimal interpolation scheme that uses a seasonal update from a free running model to estimate the background error covariance matrix.In view of the systematic biases in some observation systems,some treatments were performed on the observations before the assimilation.A coarse resolution reanalysis dataset from the system is preliminarily evaluated to demonstrate the performance of the system for the period 1992 to 2006 by comparing this dataset with other observations or reanalysis data.
基金Supported by the National Basic Research Program of China (973 Program)(No 2007CB816005)the National Natural Science Foundation of China (No 40706003)+1 种基金International S&T Cooperation Project of the Ministry of Science and Technology of China (No2009DFA21430)the COPES in China (GYHY200706005)
文摘The skewness of subsurface temperature anomaly in the equatorial Pacific Ocean shows a significant asymmetry between the east and west. A positive temperature skewness appears in the equatorial eastern Pacific, while the temperature skewness in the western and central Pacific is primarily negative. There is also an asymmetry of the temperature skewness above and below the climatological mean therrnocline in the central and western Pacific. A positive skewness appears below the thermocline, but the skewness is negative above the thermocline. The distinctive vertical asymmetry of the temperature skewness is argued to be attributed to the asymmetric temperature response to upward and downward thermocline displacement in the presence of the observed upper-ocean vertical thermal structure. Because of positive (negative) second derivative of temperature with respect to depth below (above) the thermocline, an upward and a downward shift of the thermocline with equal displacement would lead to a negative temperature skewness above the thermocline but a positive skewness below the thermocline. In the far eastern equatorial Pacific, the thermocline is close to the base of the mixed layer, the shape of the upper-ocean vertical temperature profile cannot be kept. Positive skewness appears in both below the thermocline and above the thermocline in the far eastern basin. Over the central and eastern Pacific, the anomalies of the subsurface waters tend to entrain into the surface mixed layer (by climatological mean upwelling) and then affect the SST. Hence, the positive (negative) subsurface skewness in the far eastern (central) Pacific may favor positive (negative) SST skewness, which is consistent with the observational fact that more La Nina (EI Nino) occur in the central (eastern) Pacific. The present result implies a possible new paradigm for EI Nino and La Nina amplitude asymmetry in the eastern Pacific.
基金the Knowledge Innovation Project of the Chinese Academy of Sciences (No. KZCX-SW-317-02).
文摘Maize (Zea mays L.), a staple crop grown from June to September during the rainy season on the North China Plain,is usually inter-planted in winter wheat (Triticum aestivum L.) fields about one week before harvesting of the winterwheat. In order to improve irrigation efficiency in this region of serious water shortage, field studies in 1999 and 2001, twodry seasons with less than average seasonal rainfall, were conducted with up to five irrigation applications to determineevapotranspiration, calculate the crop coefficient, and optimize the irrigation schedule with maize under mulch, as well asto establish the effects of irrigation timing and the number of applications on grain yield and water use efficiency (WUE)of maize. Results showed that with grain production at about 8 000 kg ha-1 the total evapotranspiration and WUE ofirrigated maize under mulch were about 380-400 mm and 2.0-2.2 kg m-3, respectively. Also in 2001 WUE of maizewith mulch for the treatment with three irrigations was 11.8% better than that without mulch. In the 1999 and 2001seasons, maize yield significantly improved (P = 0.05) with four irrigation applications, however, further increases werenot significant. At the same time there were no significant differences for WUE with two to four irrigation applications.In the 2001 season mulch lead to a decrease of 50 mm in the total soil evaporation, and the maize crop coefficient undermulch varied between 0.3-1.3 with a seasonal average of 1.0.