植被净初级生产力(NPP)及其与气候变化的响应研究是全球变化的核心内容之一。论文基于长时间序列遥感数据和气象数据,通过光能利用率模型(Carnegie-Ames-Stanford approach,CASA模型)模拟了1982—2010年中国草地NPP,进而分析其时空变化...植被净初级生产力(NPP)及其与气候变化的响应研究是全球变化的核心内容之一。论文基于长时间序列遥感数据和气象数据,通过光能利用率模型(Carnegie-Ames-Stanford approach,CASA模型)模拟了1982—2010年中国草地NPP,进而分析其时空变化特征及其与气候水热因子的相关性。结果表明:(1)1982—2010年中国草地年平均NPP为282.0 g C m-2a-1,年总NPP的多年平均值为988.3 Tg C;空间分布上呈现东南部高西北部低的特征。(2)近30年中国草地NPP增加速率为0.6 g C m-2a-1,呈增加趋势的面积占中国草地总面积的67.2%;总体上,中国草地NPP呈极显著和显著增加的比例(35.8%、8.0%)大于呈极显著和显著减少的比例(5.8%、4.8%);NPP明显增加的区域主要包括青藏高原西部、阿拉善高原、新疆西部;明显降低的区域主要分布在内蒙古地区;不同年代际和不同草地类型的NPP变化趋势差异明显。(3)草地NPP与降水量的相关性高于与温度的相关性。不同草地类型NPP对气温、降水量的响应程度不同,其中温性荒漠草原、温性草原、温性草甸草原的NPP与降水量均达到显著正相关(P<0.05)。展开更多
利用甘南地区2006-2007年的外业实测样方草地干物质产量和MODIS植被指数数据,建立了草地地上部分干物质产量遥感反演模型,根据根冠比和干物质转碳率对2006-2008年甘南地区草地净初级生产力(NPP,netprimary productivity)进行了估算,绘...利用甘南地区2006-2007年的外业实测样方草地干物质产量和MODIS植被指数数据,建立了草地地上部分干物质产量遥感反演模型,根据根冠比和干物质转碳率对2006-2008年甘南地区草地净初级生产力(NPP,netprimary productivity)进行了估算,绘制了甘南草地NPP年累积量空间分布格局图和NPP月度变化动态图,对不同草地植被类型的NPP差异进行了评价。研究结果表明,2006-2008年甘南草地年NPP分别达637.04,599.98和566.59 g C/m2,其空间分布具有自西南向东北逐渐减少的趋势;年内不同草地类型的NPP均在7-8月达到最大累积量;NPP累积量最高的3种草地类型是沼泽、高寒灌丛草甸和高寒草甸,3年中最大月NPP的平均值分别达到1 137.28,553.76和527.66 g C/m2;2006-2008年甘南草地NPP持续下降,年草地NPP总量的减少速率为1.2Tg/a,尤其是沼泽湿地的NPP下降明显,年平均减少速率达到了125.92 g C/m2。展开更多
植被净初级生产力(net primary productivity, NPP)在全球气候变化及碳循环研究中扮演着重要的角色,精准快速的估算NPP对评估区域生态系统承载力以及合理利用自然资源具有重要的意义。利用2011-2014年甘南地面实测草地地上生物量(aboveg...植被净初级生产力(net primary productivity, NPP)在全球气候变化及碳循环研究中扮演着重要的角色,精准快速的估算NPP对评估区域生态系统承载力以及合理利用自然资源具有重要的意义。利用2011-2014年甘南地面实测草地地上生物量(aboveground biomass, AGB)数据和根冠比系数计算的草地NPP数据,分别验证了MOD17A3 NPP产品和基于CASA(Carnegie-Ames-Stanford approach)模型估算的草地NPP的精度,分析了2000-2016年甘南地区草地NPP的时空动态变化。结果表明:基于CASA模型模拟的草地NPP精度整体上高于MOD17A3 NPP产品的精度,其均方根误差(root mean square error, RMSE)较MOD17A3 NPP小9.94 g C·m^-2;CASA模型分析的甘南地区草地NPP总体上呈现由西南向东北逐渐减少的趋势;对不同草地类型而言,沼泽类的平均NPP最高(469.07 g C·m^-2),温性草原类最低(324.18 g C·m^-2),而占研究区草地总面积比例较大的高寒草甸类和高寒灌丛草甸类草地的平均NPP分别为449.22和465.27 g C·m^-2;2000-2016年间,甘南地区大部分草地NPP稳定不变,其面积占研究区草地总面积的75.31%,NPP呈增加趋势的区域占草地面积的22.63%,而NPP呈减少趋势的区域占比最小,仅为2.06%。以上研究结果表明CASA模型在高寒地区草地NPP评估、草地资源合理利用与管理方面具有重要的应用价值。展开更多
This article mainly introduced the research progress of the carbon accumulation on grassland ecological system, which is under the condition of the carbon cycle and the climate change in China. And in carbon cycle and...This article mainly introduced the research progress of the carbon accumulation on grassland ecological system, which is under the condition of the carbon cycle and the climate change in China. And in carbon cycle and the carbon storage on the terrestrial ecosystem, the author also analyzed the status and functions of the Chinese grassland ecological system. Based on the evaluation of the primary productivity, soil organic carbon and dry falling objects, herding utilization, the grass reclamation and other factors that affect carbon accumulation on grassland ecological system, the author then put forward the primal problems and the prospect of the research on China＇s carbon accumulation of grassland ecological system. The future of carbon stock volume in grassland ecosystem in China has great potential, the fixed carbon content is about 152 Tg/a, far more than the United States, Canada, Russia and other countries.展开更多
Various environmental factors affect net primary productivity （NPP） of grassland ecosystem. Extensive reports on the effects of environmental variables on NPP can be found in literature. However, the agreement on th...Various environmental factors affect net primary productivity （NPP） of grassland ecosystem. Extensive reports on the effects of environmental variables on NPP can be found in literature. However, the agreement on the relative importance of various factors in shaping the spatial pattern of grassland NPP has not yet been reached. Here a grassland in situ NPP database comprising 602 samples in northern China for 1980-1999 was developed based on a literature review of published biomass and forage yield field measurements. Correlation analyses and dominance analysis were used to quantify the separate and combined effects of environmental variables （climate topography and soil） on spatial variation in NPP separately. Grassland NPP ranged from 4.76 g C m-2a-1 to 975.94gCm-2a-1, showing significant variations in space. NPP increased with annual precipitation and declined with annual mean temperature significantly. Specifically, precipitation had the greatest impact on deserts, followed by steppes and meadows. Grassland NPP decreased with increasing altitude because of water limitation, and positively correlated with slope, but weakly correlated with aspect. Soil quality showed positive effects on NPP. Annual precipitation was the dominant factor affecting the spatial variability of net primary productivity, followed by elevation.展开更多
The Three-River Headwaters(TRH), which is the source area of Yangtze River, Yellow River and Lancang River, is vulnerable and sensitive, and its alpine ecosystem is considered an important barrier for China’s ecologi...The Three-River Headwaters(TRH), which is the source area of Yangtze River, Yellow River and Lancang River, is vulnerable and sensitive, and its alpine ecosystem is considered an important barrier for China’s ecological security. Understanding the impact of climate changes is essential for determining suitable measures for ecological environmental protection and restoration against the background of global climatic changes. However, different explanations of the interannual trends in complex alpine ecosystems have been proposed due to limited availability of reliable data and the uncertainty of the model itself. In this study, the remote sensing-process coupled model(GLOPEM-CEVSA) was used to estimate the net primary productivity(NPP) of vegetation in the TRH region from 2000 to 2012. The estimated NPP significantly and linearly correlated with the above-ground biomass sampled in the field(the multiple correlative coefficient R2 = 0.45, significant level P < 0.01) and showed better performance than the MODIS productivity product, i.e. MOD17 A3,(R2 = 0.21). The climate of TRH became warmer and wetter during 1990-2012, and the years 2000 to 2012 were warmer and wetter than the years1990–2000. Responding to the warmer and wetter climate, the NPP had an increasing trend of 13.7 g m^–2(10 yr)^–1 with a statistical confidence of 86%(P = 0.14). Among the three basins, the NPP of the Yellow River basin increased at the fastest rate of 17.44 g m^–2(10 yr)^–1(P = 0.158), followed by the Yangtze River basin, and the Lancang River, which was the slowest with a rate of 12.2 g m^–2(10 yr)^–1 and a statistical confidence level of only 67%. A multivariate linear regression with temperature and precipitation as the independent variables and NPP as the dependent variable at the pixel level was used to analyze the impacts of climatic changes on the trend of NPP. Both temperature and precipitation can explain the interannual variability of 83% in grassland NPP in the whole region, and can explain high, medium and low coverage of 78%, 84% and 83%, respectively, for grassland in the whole region. The results indicate that climate changes play a dominant role in the interannual trend of vegetation productivity in the alpine ecosystems on Qinghai-Tibetan Plateau. This has important implications for the formulation of ecological protection and restoration policies for vulnerable ecosystems against the background of global climate changes.展开更多
文摘植被净初级生产力(NPP)及其与气候变化的响应研究是全球变化的核心内容之一。论文基于长时间序列遥感数据和气象数据,通过光能利用率模型(Carnegie-Ames-Stanford approach,CASA模型)模拟了1982—2010年中国草地NPP,进而分析其时空变化特征及其与气候水热因子的相关性。结果表明:(1)1982—2010年中国草地年平均NPP为282.0 g C m-2a-1,年总NPP的多年平均值为988.3 Tg C;空间分布上呈现东南部高西北部低的特征。(2)近30年中国草地NPP增加速率为0.6 g C m-2a-1,呈增加趋势的面积占中国草地总面积的67.2%;总体上,中国草地NPP呈极显著和显著增加的比例(35.8%、8.0%)大于呈极显著和显著减少的比例(5.8%、4.8%);NPP明显增加的区域主要包括青藏高原西部、阿拉善高原、新疆西部;明显降低的区域主要分布在内蒙古地区;不同年代际和不同草地类型的NPP变化趋势差异明显。(3)草地NPP与降水量的相关性高于与温度的相关性。不同草地类型NPP对气温、降水量的响应程度不同,其中温性荒漠草原、温性草原、温性草甸草原的NPP与降水量均达到显著正相关(P<0.05)。
文摘利用甘南地区2006-2007年的外业实测样方草地干物质产量和MODIS植被指数数据,建立了草地地上部分干物质产量遥感反演模型,根据根冠比和干物质转碳率对2006-2008年甘南地区草地净初级生产力(NPP,netprimary productivity)进行了估算,绘制了甘南草地NPP年累积量空间分布格局图和NPP月度变化动态图,对不同草地植被类型的NPP差异进行了评价。研究结果表明,2006-2008年甘南草地年NPP分别达637.04,599.98和566.59 g C/m2,其空间分布具有自西南向东北逐渐减少的趋势;年内不同草地类型的NPP均在7-8月达到最大累积量;NPP累积量最高的3种草地类型是沼泽、高寒灌丛草甸和高寒草甸,3年中最大月NPP的平均值分别达到1 137.28,553.76和527.66 g C/m2;2006-2008年甘南草地NPP持续下降,年草地NPP总量的减少速率为1.2Tg/a,尤其是沼泽湿地的NPP下降明显,年平均减少速率达到了125.92 g C/m2。
文摘植被净初级生产力（net primary productivity,NPP）及其对气候变化的响应研究是全球变化的核心内容之一。基于地理信息系统和卫星遥感应用技术,利用CASA模型估算了2001-2008年甘南草地NPP,在模型验证的基础上,分析了甘南草地NPP空间分布格局和时间分布特征。结果表明,1）2001-2008年甘南草地多年平均NPP为483.41 g C/（m2.a）,大体呈现由西南向东北逐渐减少的趋势,单位面积多年平均NPP在海拔3 000~3 500 m最高,达到497.07 g C/（m2.a）;2）甘南草地植被生长季节变化明显,主要生长期集中在第177~240天;3）甘南草地NPP呈现增加趋势,增长趋势最明显的草地类型是低平地草甸类,而沼泽的变幅最小,通过与8年间温度和降水的分析可以看出,影响甘南草地NPP变化的主要驱动力是降水量。
文摘植被净初级生产力(net primary productivity, NPP)在全球气候变化及碳循环研究中扮演着重要的角色,精准快速的估算NPP对评估区域生态系统承载力以及合理利用自然资源具有重要的意义。利用2011-2014年甘南地面实测草地地上生物量(aboveground biomass, AGB)数据和根冠比系数计算的草地NPP数据,分别验证了MOD17A3 NPP产品和基于CASA(Carnegie-Ames-Stanford approach)模型估算的草地NPP的精度,分析了2000-2016年甘南地区草地NPP的时空动态变化。结果表明:基于CASA模型模拟的草地NPP精度整体上高于MOD17A3 NPP产品的精度,其均方根误差(root mean square error, RMSE)较MOD17A3 NPP小9.94 g C·m^-2;CASA模型分析的甘南地区草地NPP总体上呈现由西南向东北逐渐减少的趋势;对不同草地类型而言,沼泽类的平均NPP最高(469.07 g C·m^-2),温性草原类最低(324.18 g C·m^-2),而占研究区草地总面积比例较大的高寒草甸类和高寒灌丛草甸类草地的平均NPP分别为449.22和465.27 g C·m^-2;2000-2016年间,甘南地区大部分草地NPP稳定不变,其面积占研究区草地总面积的75.31%,NPP呈增加趋势的区域占草地面积的22.63%,而NPP呈减少趋势的区域占比最小,仅为2.06%。以上研究结果表明CASA模型在高寒地区草地NPP评估、草地资源合理利用与管理方面具有重要的应用价值。
文摘This article mainly introduced the research progress of the carbon accumulation on grassland ecological system, which is under the condition of the carbon cycle and the climate change in China. And in carbon cycle and the carbon storage on the terrestrial ecosystem, the author also analyzed the status and functions of the Chinese grassland ecological system. Based on the evaluation of the primary productivity, soil organic carbon and dry falling objects, herding utilization, the grass reclamation and other factors that affect carbon accumulation on grassland ecological system, the author then put forward the primal problems and the prospect of the research on China＇s carbon accumulation of grassland ecological system. The future of carbon stock volume in grassland ecosystem in China has great potential, the fixed carbon content is about 152 Tg/a, far more than the United States, Canada, Russia and other countries.
基金"Strategic Priority Research Program-Climate Change:Carbon Budget and Relevant Issues" of the Chinese Academy of Sciences(Project Number XDA05090305)
文摘Various environmental factors affect net primary productivity （NPP） of grassland ecosystem. Extensive reports on the effects of environmental variables on NPP can be found in literature. However, the agreement on the relative importance of various factors in shaping the spatial pattern of grassland NPP has not yet been reached. Here a grassland in situ NPP database comprising 602 samples in northern China for 1980-1999 was developed based on a literature review of published biomass and forage yield field measurements. Correlation analyses and dominance analysis were used to quantify the separate and combined effects of environmental variables （climate topography and soil） on spatial variation in NPP separately. Grassland NPP ranged from 4.76 g C m-2a-1 to 975.94gCm-2a-1, showing significant variations in space. NPP increased with annual precipitation and declined with annual mean temperature significantly. Specifically, precipitation had the greatest impact on deserts, followed by steppes and meadows. Grassland NPP decreased with increasing altitude because of water limitation, and positively correlated with slope, but weakly correlated with aspect. Soil quality showed positive effects on NPP. Annual precipitation was the dominant factor affecting the spatial variability of net primary productivity, followed by elevation.
基金National Key Research and Development Program of China(2016YFC0500203)Science and Technology Program of Qinghai Province(2018-ZJ-T09,2017-SF-A6)
文摘The Three-River Headwaters(TRH), which is the source area of Yangtze River, Yellow River and Lancang River, is vulnerable and sensitive, and its alpine ecosystem is considered an important barrier for China’s ecological security. Understanding the impact of climate changes is essential for determining suitable measures for ecological environmental protection and restoration against the background of global climatic changes. However, different explanations of the interannual trends in complex alpine ecosystems have been proposed due to limited availability of reliable data and the uncertainty of the model itself. In this study, the remote sensing-process coupled model(GLOPEM-CEVSA) was used to estimate the net primary productivity(NPP) of vegetation in the TRH region from 2000 to 2012. The estimated NPP significantly and linearly correlated with the above-ground biomass sampled in the field(the multiple correlative coefficient R2 = 0.45, significant level P < 0.01) and showed better performance than the MODIS productivity product, i.e. MOD17 A3,(R2 = 0.21). The climate of TRH became warmer and wetter during 1990-2012, and the years 2000 to 2012 were warmer and wetter than the years1990–2000. Responding to the warmer and wetter climate, the NPP had an increasing trend of 13.7 g m^–2(10 yr)^–1 with a statistical confidence of 86%(P = 0.14). Among the three basins, the NPP of the Yellow River basin increased at the fastest rate of 17.44 g m^–2(10 yr)^–1(P = 0.158), followed by the Yangtze River basin, and the Lancang River, which was the slowest with a rate of 12.2 g m^–2(10 yr)^–1 and a statistical confidence level of only 67%. A multivariate linear regression with temperature and precipitation as the independent variables and NPP as the dependent variable at the pixel level was used to analyze the impacts of climatic changes on the trend of NPP. Both temperature and precipitation can explain the interannual variability of 83% in grassland NPP in the whole region, and can explain high, medium and low coverage of 78%, 84% and 83%, respectively, for grassland in the whole region. The results indicate that climate changes play a dominant role in the interannual trend of vegetation productivity in the alpine ecosystems on Qinghai-Tibetan Plateau. This has important implications for the formulation of ecological protection and restoration policies for vulnerable ecosystems against the background of global climate changes.
