植被的降水利用效率(Precipitation use efficiency,PUE)是表征植被生产力对降水量时空动态变化响应特征的重要指示器,对了解干旱环境下植被生产力的变化尤为关键。基于中国干旱半干旱区2000—2020年的植被净初级生产力、降水量、气温...植被的降水利用效率(Precipitation use efficiency,PUE)是表征植被生产力对降水量时空动态变化响应特征的重要指示器,对了解干旱环境下植被生产力的变化尤为关键。基于中国干旱半干旱区2000—2020年的植被净初级生产力、降水量、气温、土地利用类型和地形等数据,分析了中国干旱半干旱区植被降水利用效率的时空特征及其变化趋势,探究了植被PUE与气候因子的关联以及气候变化下土地利用和地形对植被PUE的影响。研究结果表明:(1)2000—2020年中国干旱半干旱区植被平均PUE为0.41 g C m^(-2)mm^(-1),不同土地利用类型下植被PUE的大小顺序为:草地<湿地<灌木<耕地<林地。(2)植被PUE年际变化整体呈现波动上升趋势,上升速率为0.004 g C m^(-2)mm^(-1),其中呈现显著改善趋势的面积占总面积的12.24%。(3)气温升高在不同程度上对大多数植被PUE起到促进作用,而降水增多则会抑制绝大多数区域的植被PUE。植被较少的区域,植被降水利用效率与气温、降水两气候因子基本无关。(4)随着海拔的升高,植被PUE呈现出先减后增再减的趋势。随着海拔的变化,气温依然与植被PUE呈正相关,降水依然与植被PUE呈负相关。研究结果可为中国干旱半干旱区生态系统保护、恢复以及可持续利用提供科学参考。展开更多
Hydrological service is a hot issue in the current researches of ecosystem service, particularly in the upper reaches of mountain rivers in dry land areas, where the Qilian Mountain is a representative one. The Qilian...Hydrological service is a hot issue in the current researches of ecosystem service, particularly in the upper reaches of mountain rivers in dry land areas, where the Qilian Mountain is a representative one. The Qilian Mountain, where forest, shrubland and grassland consist of its main ecosystems, can provide fresh water and many other ecosystem services, through a series of eco-hydrological process such as precipitation interception, soil water storage, and fresh water provision. Thus, monitoring water regulation and assessing the hydrological service of the Qilian Mountain are meaningful and helpful for the healthy development of the lower reaches of arid and semi-arid areas. In recent 10 years, hydrological services have been widely researched in terms of scale and landscape pattern, including water conservation, hydrological responses to afforestation and their ecological effects. This study, after analyzing lots of current models and applications of geographical information system（GIS） in hydrological services, gave a scientific and reasonable evaluation of mountain ecosystem in eco-hydrological services, by employing the combination of international forefronts and contentious issues into the Qilian Mountain. Assessments of hydrological services at regional or larger scales are limited compared with studies within watershed scale in the Qilian Mountain. In our evaluation results of forest ecosystems, it is concluded that long-term observation and dynamic monitoring of different types of ecosystem are indispensable, and the hydrological services and the potential variation in water supplement on regional and large scales should be central issues in the future research.v展开更多
The definition of a drought index is the foundation of drought research.However,because of the complexity of drought,there is no a unified drought index appropriate for different drought types and objects at the same ...The definition of a drought index is the foundation of drought research.However,because of the complexity of drought,there is no a unified drought index appropriate for different drought types and objects at the same time.Therefore,it is crucial to determine the regional applicability of various drought indices.Using terrestrial water storage obtained from the Gravity Recovery And Climate Experiment,and the observed soil moisture and streamflow in China,we evaluated the regional applicability of seven meteorological drought indices:the Palmer Drought Severity Index(PDSI),modified PDSI(PDSI_CN) based on observations in China,self-calibrating PDSI(scPDSI),Surface Wetness Index(SWI),Standardized Precipitation Index(SPI),Standardized Precipitation Evapotranspiration Index(SPEI),and soil moisture simulations conducted using the community land model driven by observed atmospheric forcing(CLM3.5/ObsFC).The results showed that the scPDSI is most appropriate for China.However,it should be noted that the scPDSI reduces the value range slightly compared with the PDSI and PDSI_CN;thus,the classification of dry and wet conditions should be adjusted accordingly.Some problems might exist when using the PDSI and PDSI_CN in humid and arid areas because of the unsuitability of empiricalparameters.The SPI and SPEI are more appropriate for humid areas than arid and semiarid areas.This is because contributions of temperature variation to drought are neglected in the SPI,but overestimated in the SPEI,when potential evapotranspiration is estimated by the Thornthwaite method in these areas.Consequently,the SPI and SPEI tend to induce wetter and drier results,respectively.The CLM3.5/ObsFC is suitable for China before 2000,but not for arid and semiarid areas after 2000.Consistent with other drought indices,the SWI shows similar interannual and decadal change characteristics in detecting annual dry/wet variations.Although the long-term trends of drought areas in China detected by these seven drought indices during 1961-2013 are consistent,obvious differences exist among the values of drought areas,which might be attributable to the definitions of the drought indices in addition to climatic change.展开更多
文摘植被的降水利用效率(Precipitation use efficiency,PUE)是表征植被生产力对降水量时空动态变化响应特征的重要指示器,对了解干旱环境下植被生产力的变化尤为关键。基于中国干旱半干旱区2000—2020年的植被净初级生产力、降水量、气温、土地利用类型和地形等数据,分析了中国干旱半干旱区植被降水利用效率的时空特征及其变化趋势,探究了植被PUE与气候因子的关联以及气候变化下土地利用和地形对植被PUE的影响。研究结果表明:(1)2000—2020年中国干旱半干旱区植被平均PUE为0.41 g C m^(-2)mm^(-1),不同土地利用类型下植被PUE的大小顺序为:草地<湿地<灌木<耕地<林地。(2)植被PUE年际变化整体呈现波动上升趋势,上升速率为0.004 g C m^(-2)mm^(-1),其中呈现显著改善趋势的面积占总面积的12.24%。(3)气温升高在不同程度上对大多数植被PUE起到促进作用,而降水增多则会抑制绝大多数区域的植被PUE。植被较少的区域,植被降水利用效率与气温、降水两气候因子基本无关。(4)随着海拔的升高,植被PUE呈现出先减后增再减的趋势。随着海拔的变化,气温依然与植被PUE呈正相关,降水依然与植被PUE呈负相关。研究结果可为中国干旱半干旱区生态系统保护、恢复以及可持续利用提供科学参考。
基金Under the auspices of Ministry of Science and Technology of China(No.2012BAC08B01)
文摘Hydrological service is a hot issue in the current researches of ecosystem service, particularly in the upper reaches of mountain rivers in dry land areas, where the Qilian Mountain is a representative one. The Qilian Mountain, where forest, shrubland and grassland consist of its main ecosystems, can provide fresh water and many other ecosystem services, through a series of eco-hydrological process such as precipitation interception, soil water storage, and fresh water provision. Thus, monitoring water regulation and assessing the hydrological service of the Qilian Mountain are meaningful and helpful for the healthy development of the lower reaches of arid and semi-arid areas. In recent 10 years, hydrological services have been widely researched in terms of scale and landscape pattern, including water conservation, hydrological responses to afforestation and their ecological effects. This study, after analyzing lots of current models and applications of geographical information system（GIS） in hydrological services, gave a scientific and reasonable evaluation of mountain ecosystem in eco-hydrological services, by employing the combination of international forefronts and contentious issues into the Qilian Mountain. Assessments of hydrological services at regional or larger scales are limited compared with studies within watershed scale in the Qilian Mountain. In our evaluation results of forest ecosystems, it is concluded that long-term observation and dynamic monitoring of different types of ecosystem are indispensable, and the hydrological services and the potential variation in water supplement on regional and large scales should be central issues in the future research.v
基金supported by the National Basic Research Program of China(Grant No.2012CB956201)the National Natural Science Foundation of China(Grant Nos.41275085,41530532 & 41305062)+1 种基金the National Key Technology R&D Program of China(Grant No.2013BAC10B02)China Special Fund for Meteorological Research in the Public Interest(Grant No.GYHY201506001-1)
文摘The definition of a drought index is the foundation of drought research.However,because of the complexity of drought,there is no a unified drought index appropriate for different drought types and objects at the same time.Therefore,it is crucial to determine the regional applicability of various drought indices.Using terrestrial water storage obtained from the Gravity Recovery And Climate Experiment,and the observed soil moisture and streamflow in China,we evaluated the regional applicability of seven meteorological drought indices:the Palmer Drought Severity Index(PDSI),modified PDSI(PDSI_CN) based on observations in China,self-calibrating PDSI(scPDSI),Surface Wetness Index(SWI),Standardized Precipitation Index(SPI),Standardized Precipitation Evapotranspiration Index(SPEI),and soil moisture simulations conducted using the community land model driven by observed atmospheric forcing(CLM3.5/ObsFC).The results showed that the scPDSI is most appropriate for China.However,it should be noted that the scPDSI reduces the value range slightly compared with the PDSI and PDSI_CN;thus,the classification of dry and wet conditions should be adjusted accordingly.Some problems might exist when using the PDSI and PDSI_CN in humid and arid areas because of the unsuitability of empiricalparameters.The SPI and SPEI are more appropriate for humid areas than arid and semiarid areas.This is because contributions of temperature variation to drought are neglected in the SPI,but overestimated in the SPEI,when potential evapotranspiration is estimated by the Thornthwaite method in these areas.Consequently,the SPI and SPEI tend to induce wetter and drier results,respectively.The CLM3.5/ObsFC is suitable for China before 2000,but not for arid and semiarid areas after 2000.Consistent with other drought indices,the SWI shows similar interannual and decadal change characteristics in detecting annual dry/wet variations.Although the long-term trends of drought areas in China detected by these seven drought indices during 1961-2013 are consistent,obvious differences exist among the values of drought areas,which might be attributable to the definitions of the drought indices in addition to climatic change.
