Observation and modeling of NPP for Pinus elliottii plantation in subtropical China     

《中国科学D辑(英文版)》2008,(7)

Based on the stem analysis of 59 individuals of Pinus elliottii in combination with tree biomass models, we calculated annual biomass increment of forest plots at Qianyanzhou Ecological Station, Chinese Academy of Sciences in subtropical China. In addition, canopy layer and community NPP were calcu- lated based on 12 years’ litter fall data. NPP of the 21-year-old forest was estimated by using the BIOME BGC model; and both measured NPP and estimated NPP were compared with flux data. Community biomass was 10574 g·m-2; its distribution patterns in tree layer, shrub layer, herbaceous layer, tree root, herbaceous and shrub roots and fine roots were 7542, 480, 239, 1810, 230, 274 and 239 g·m-2, respectively. From 1999 to 2004, the average annual growth rate and litter fall were 741 g·m-2·a-1 (381.31 gC·m-2·a-1) and 849 g·m?2·a?1 (463 gC·m-2·a-1), respectively. There was a significant corre- lation between annual litter fall and annual biomass increment; and the litter fall was 1.19 times the biomass increment of living trees. From 1985 to 2005, average NPP and GPP values based on BGC modeling were 630.88 (343.31 - 906.42 gC·m-2·a-1) and 1 800 gC·m-2·a-1 (1351.62 - 2318.26 gC·m-2·a-1). Regression analysis showed a linear relationship (R2=0.48) between the measured and simulated tree layer NPP values. NPP accounted for 30.2% (25.6%-32.9%) of GPP, while NEP ac- counted for 57.5% (48.1%-66.5%) of tree-layer NPP and 41.74% (37%-52%) of stand NPP. Soil respi- ration accounted for 77.0% of measured tree NPP and 55.9% of the measured stand NPP. NEE based on eddy covariance method was 12.97% higher than the observed NEP.  相似文献   

庙岛群岛北五岛生态系统净初级生产力与景观格局时空分布异质性研究     

殷丽婷  郑伟  高猛  路景钫 《海洋学报》2020,42(6):110-118

利用ArcGIS10.2、ENVI5.1、SPSS26等软件,本文基于经典CASA模型估算了2005年、2010年、2017年庙岛群岛北五岛的净初级生产力(Net Primary Productivity, NPP),从季节、岛屿、景观类型、地形梯度等多种角度分析了NPP的时空分布异质性;进而分析了2005年、2010年、2017年北五岛的景观格局时空分布异质性;探讨了NPP与景观格局时空变化之间的关系及其原因。结果表明:庙岛群岛北五岛平均全年NPP总量为7 520.54 t/a(以碳计),平均密度为406.07 g/(m2·a) (以碳计);NPP分布呈明显的时空分异性;各景观类型平均面积由大到小依次为:针叶林、阔叶林、建设用地、草地、耕地;其NPP平均密度由大到小依次为:阔叶林、针叶林、耕地、草地、建设用地;各景观NPP平均密度随坡度和高差的增大先上升后出现平缓下降态势;坡向对林地NPP影响较大,半阴坡林地NPP平均密度最大;不同地形梯度的NPP年平均密度随时间推移总体呈下降态势;NPP高值出现在山林区域,低值主要在建设用地区域;由于自然地理条件、植物自身生长条件和人类活动强度等原因,NPP时空异质性分布受季节差异、景观格局时空异质性和地形因子影响显著。  相似文献   

基于卫星遥感和POI数据的人口空间化研究——以广州市为例     

赵鑫  宋英强  刘轶伦  陈飞香  胡月明 《热带地理》2020,40(1):101-109

以广州市为例,基于NPP/VIIRS夜间灯光、土地利用、POI（Points of Interest）等自然地理和社会经济因素,构建了人口空间化指标体系,采用主成分赋权法确定人口分布权重,利用GIS技术对人口统计数据进行了空间化处理。结果显示：综合考虑了自然地理和社会经济因素的人口空间化结果与真实的人口空间格局相吻合,空间分辨率为30 m,且相对误差绝对值＜25%的乡镇有62个,所占比例为36.47%;而不加POI数据得到的人口空间化结果,相对绝对值＜25%的乡镇有33个,所占比例约为20%,精度明显降低。结果表明：1）综合考虑NPP/VIIRS夜间灯光、土地利用、POI等自然地理和社会经济因素,有助于实现精度较高的人口空间化结果;2）将能够反映微观细节信息的POI数据引入人口空间化研究,扩展了人口空间化的数据源,并且可以提高人口空间化结果的精度。  相似文献   

农田生产力监测中3种多源遥感数据融合方法的对比分析     

罗亮  闫慧敏  牛忠恩 《地球信息科学学报》2018,20(2):268-279

借助多源遥感数据融合技术能够得到高时空分辨率的遥感数据,可以为高精度农业遥感动态监测提供强有力的支持。在诸多融合算法不断发展的情况下,评估每种方法的特点及其适用性,有助于找到最适宜的融合方法,进而应用于农田生产力监测的实践之中。本研究根据高标准农田建设成效评估对高时空分辨率生产力信息的需求,以宁夏灵武市农业综合开发项目区为实验区,采用线性拟合法、时序拟合法、时空融合法3种多源遥感数据融合方法,融合空间分辨率30 m的Landsat遥感数据的空间精度信息与空间分辨率500 m、时间步长8 d的MODIS遥感数据的高时相信息并对比不同方法对于农田生产力的空间格局精细化描述能力、对于农田生产力变化监测的能力以及运算速度的差异。研究结果表明：① 3种融合方法融合的30 mNPP数据均能显示出道路、田埂等线状裸地与田间NPP的差异,但是时序拟合法、时空融合法比线性拟合法更加清晰;在NPP相对均匀的田块内部,时空融合法比时序拟合法更能体现出农田内部均匀度的差异。② 线性拟合法仅适用于农田生产力年季变化的评估,不能用于作物生产力的实时动态监测;时序拟合法和时空融合法适用于农田生产力变化动态监测且时序拟合法适宜于大范围监测。③ 3种方法的计算速度差异显著,线性拟合法计算速率最快,时空融合法计算速率最慢;线性拟合法计算速率分别是时序拟合法和时空融合法的1.5倍和20倍。  相似文献   

基于GF-1/WFV数据的三江源草地月度NPP反演研究     

袁烨城  李宝林  王双  孙庆龄  张涛  张志军 《地球信息科学学报》2018,20(12):1799-1809

准确认识三江源植被生产力月度尺度的时空格局变化,对三江源畜牧业生产以及生态保护政策制定具有重要意义,可稳定获取的重访周期为4 d的16 m分辨率GF-1/WFV数据使中等空间分辨率的月度NPP产品生产成为可能。本文建立了一套以GF-1/WFV为基本数据源的中等空间分辨率草地月度NPP估算技术方法,并评估了其在三江源地区应用的可行性。在黄河源区玛多县的实验表明以GF-1/WFV为基础,以MODIS13Q1数据为补充,可以获得覆盖全区的中等空间分辨率月度NDVI数据,据其反演得到的草地NPP,地面验证精度在70%以上,优于MODIS NPP产品精度,且能更为详细地反映草地生产力变化的空间差异,在青海三江源地区利用GF-1/WFV数据生产中等空间分辨率的草地月度NPP产品是可行的。  相似文献   

多源信息多尺度视角的南京市街道级人口模拟研究     

许玲丽  颜梅春 《测绘通报》2019,(2):71-75

人口是重要的社会和生态环境因素,掌握人口信息有利于资源配置和环境管理。本文以南京市的街道级行政区域作为基本对象单元,分别从市级、市郊级和城市化度3个尺度,人口总量和人口密度2个方面,使用NPP/VⅡRS夜间灯光数据、大数据中的关注点POI数据、Landsat 8卫星OLI影像的建筑用地指数IBI,进行了人口模拟研究。结果如下：①在市级层面,人口密度模拟效果优于人口总量的,POI数据模拟效果最佳,确定性系数为0.87,其次是建筑用地指数0.81,夜间灯光数0.77;②在市郊级层面,郊区的人口密度拟合效果优于市区的;③在城市化度方面,中度城市化的街道人口密度与NPP/VⅡRS的幂函数关系最佳,确定性系数为0.99,低度和高度城市化的街道人口密度与POI的对数关系拟合效果相对好些,确定性系数分别为0.65和0.44;中度和低度城市化街道的人口总量与3个因素数据的多元线性回归模型效果最佳,确定性系数分别为0.91和0.78。结果说明中度城市化街道的人口模拟效果最好。本文研究拓展了城市人口估算的广度和深度,可为相关工作提供思路上的借鉴。  相似文献   

Simulating Crop Net Primary Production in China from 2000 to 2050 by Linking the Crop-C model with a FGOALS's Model Climate Change Scenario     

张稳  黄耀  孙文娟  俞永强 《大气科学进展》2007,24(5)

Net primary production(NPP)of crop represents the capacity of sequestrating atmospheric CO_2 in agro-ecosystem,and it plays an important role in terrestrial carbon cycling.By linking the Crop-C model with climate change scenario projected by a coupled GCM FGOALS via geographical information system (GIS)techniques,crop NPP in China was simulated from 2000 to 2050.The national averaged surface air temperature from FGOALS is projected to increase by 1.0℃over this period and the corresponding atmospheric CO_2 concentration is 535 ppm by 2050 under the IPCC AIB scenario.With a spatial resolution of 10×10 km~2,model simulation indicated that an annual average increase of 0.6 Tg C yr~(-1)(Tg=10~(12)g) would be possible under the AIB scenario.The NPP in the late 2040s would increase by 5%(30 Tg C) within the 98×10~6 hm~2 cropland area in contrast with that in the early 2000s.A further investigation suggested that changes in the NPP would not be evenly distributed in China.A higher increase would occur in a majority of regions located in eastern and northwestern China,while a slight reduction would appear in Hebei and Tianjin in northern China.The spatial characteristics of the crop NPP change are attributed primarily to the uneven distribution of temperature change.  相似文献   

Predicting and assessing changes in NPP based on multi-scenario land use and cover simulations on the Loess Plateau     

JIANG Xiaowei  BAI Jianjun 《地理学报(英文版)》2021,31(7):977-996

Land use/cover change(LUCC)is a major factor affecting net primary production(NPP).According to the LUCC of the Loess Plateau from 2005 to 2015,the LUCC patterns in 2025 in three scenarios were predicted by using the Future Land Use Simulation(FLUS)model.Furthermore,taking the average NPP of various land use/cover types in 16 years as the reference scale,the changes in NPP in multi-scenario simulations are predicted and an-alyzed,and the impact of different land use/cover transfers on NPP is quantified.The results are as follows:(1)The land use/cover changes greatly in the baseline and fast development scenarios,and changes relatively little in the ecological protection scenarios.(2)The changes in NPP in different scenarios reflected the significant difference in the ecological protection effect.All the three scenarios promote an NPP increase,but the ecological protection sce-nario can promote NPP increases the most.(3)The changes in NPP caused by LUCC in the three scenarios reflected the significant difference in the various land use/cover types pro-tection effect.Analyzing and predicting NPP changes in multi-scenario LUCC simulations in the future can provide a theoretical basis for decision makers to judge the future changes in ecological environments and ecological protection effects against different policy back-grounds.  相似文献   

基于CASA模型的2005—2019年云南断陷盆地NPP时空变化研究   总被引：1，自引：0，他引：1  

张鑫彤  吴秀芹 《地球学报》2021,42(3):426-434

净初级生产力(NPP)是研究生态系统中物质和能量流动的基础,NPP的空间分布与区域植被生长状况、地形、气候等因素息息相关,其变化可以反映一个地区生态环境质量状况.岩溶断陷盆地是新生代断裂活动及溶蚀作用共同形成的山间盆地的一种类型,由于其地形复杂、气候反差大且土地抗干扰能力差,石漠化现象极为严重且治理难度大.断陷盆地主要...  相似文献   

Assessing the spatio-temporal variability of vegetation productivity in Africa: quantifying the relative roles of climate variability and human activities     

《International Journal of Digital Earth》2013,6(9):879-900

ABSTRACT

Quantitative attribution at the individual pixel level of the relative contributions of climate variability and human activities to vegetation productivity dynamics across Africa is generally lacking. This is because of the difficulty in establishing a baseline or potential vegetation against which the relative impacts of these factors can be assessed. This study addresses these gaps. First, annual potential net primary productivity (NPP_P) for 2000–2014 was estimated for Africa using a model constructed from samples of NPP and environmental covariates from protected areas. Second, trends in NPP_P, actual NPP (NPP_A), and human-appropriated NPP (NPP_H?=?NPP_P ? NPP_A) were estimated and used in quantifying the relative contributions of climate and human activities to NPP dynamics. Over 2000–2014, NPP improvement was largely concentrated in equatorial and northern Africa, while subequatorial Africa exhibited the most NPP decline. Parts of Mali, Burkina Faso, and the central Africa region are associated with the greatest influence of climate-driven NPP improvement. Areas where humans dominated NPP decline include parts of Ethiopia and South Africa. Climate had a stronger role in driving NPP decline in subequatorial Africa. Nonetheless, further work is required to validate the results of this study with high-resolution imagery and field information.  相似文献