洞庭湖植被对降水的响应

We analyzed the Normalized Difference Vegetation Index (NDVI) from satellite images and precipitation data from meteorological stations from 1998 to 2007 in the Dongting Lake wetland watershed to better understand the eco-hydrological effect of atmospheric precipitation and its relationship with vegetation. First,we analyzed its general spatio-temporal distribution using its mean,standard deviation and linear trend. Then,we used the Empirical Orthogonal Functions (EOF) method to decompose the NDVI and precipitation data into spatial and temporal modes. We selected four leading modes based on North and Scree test rules and analyzed the synchronous seasonal and inter-annual variability between the vegetation index and precipitation,distinguishing time-lagged correlations between EOF modes with the correlative degree analysis method. According to our detailed analyses,the vegetation index and precipitation exhibit a prominent correlation in spatial distribution and seasonal variation. At the 90% confidence level,the time lag is around 110 to 140 days,which matches well with the seasonal variation.     

Inter-annual variability and interaction of remote-sensed vegetation index and atmospheric precipitation in the Aral Sea region

The remotely sensed Normalized Difference Vegetation Index (AVHRR NDVI) and precipitation data were analysed in the Aral Sea region in Central Asia during two recent decades. Both variables exhibited pronounced seasonal variation, with maximum precipitation in March and maximum NDVI in May–June. The regions of synchronous seasonal and inter-annual variability between the vegetation index and precipitation were distinguished using the Empirical Orthogonal Functions (EOF) method and time-lagged correlations between EOF modes. At a seasonal scale, precipitation and the vegetation index were correlated with a time lag from 1 to 6 months in different regions with peak plant growth following precipitation maxima.     

近15a新疆不同类型植被NDVI时空动态变化及对气候变化的响应

为了研究新疆不同类型植被对气候变化的响应,以地带性划分的植被类型作为研究对象,1998-2012年为时间尺度,利用GIS的空间分析方法结合数学统计方法,分析了新疆各地带植被覆盖变化的时空分布特征;并采用"多元回归+残差插值"的方法,模拟了气温和降水量的空间分布;利用SPOT VGT/NDVI数据以及气候数据(气温和降水量数据),分析了5个不同地带植被的动态变化、年际变化和生长季内各月变化及其对气候变化的响应。结果表明:(1)新疆各地带植被覆盖度存在着显著差异,其中,温带北部草原地带高植被区和浓密植被区的范围较广,植被覆盖度较高,而高寒荒漠地带的极低植被区占该地带面积的一半以上,且植被覆盖度最低。(2)新疆各地带植被覆盖在近15 a间呈波动增加的趋势,5个地带的植被覆盖均有所改善,其中,高寒荒漠地带和暖温带半灌木、灌木地带的植被覆盖改善较为明显,其余3个地带均有少部分地区出现轻微改善现象。(3)温带半灌木、矮乔木荒漠地带,暖温带半灌木、灌木荒漠地带和温带半灌木、灌木荒漠地带4~10月的平均气温呈上升趋势,而温带北部草原地带、高寒荒漠地带对应的平均气温则出现下降趋势。5个地带的降水量在该时段内均表现为下降趋势。(4)基于年际尺度,新疆各地带植被NDVI与气温、降水量的相关性均不显著;基于月尺度,各地带植被NDVI受降水量的影响比气温大。同时,仅有暖温带半灌木、灌木荒漠地带植被NDVI与气温存在1个月的滞后性,其余4个地带对气温和降水均不存在滞后性。     

近15 a黄土高原植被覆盖时空变化及驱动力分析

研究黄土高原地区植被覆盖变化及其驱动因素可以揭示研究区气候变化和人工生态调节过程对植被变化的影响。基于500 m分辨率的MODIS-NDVI数据和同期气象数据,运用均值法、斜率分析法、相关分析法及残差法,分析了2001-2015年黄土高原的植被时空演变变化特征及其驱动因素。结果表明：近15 a黄土高原植被在季度上总体都呈现增加趋势且存在一定差异,夏、秋季植被增加最为明显;黄土高原植被覆盖在空间上呈现自东南向西北递减的分布特征;植被NDVI变化在不同季节上都存在明显的空间差异;黄土高原植被NDVI对气温、降水的响应关系有明显的季节差异,并在空间上与降水的相关性显著,与温度相关性不明显;人类活动对植被覆盖变化有双重影响,其中生态恢复工程是黄土高原中部地区植被覆盖快速增加的重要因素。     

温度与降水变化的小波分析及其环境效应解释——以东北农牧交错区为例

中国东北农牧交错区属于环境变化的过渡区域和敏感区域 ,是最容易感受气候变化的地带之一。该文运用小波分析方法 ,对 5 0年代以来东北农牧交错区典型站点的温度和降水变化情景进行了分析 ,主要分析了其变化的多尺度特征和规律 ;区域和样地分析结果表明 ,降水与温度的时空变化是导致土地退化和环境变化的重要驱动力     

中国草原区植被变化及其对气候变化的响应

利用1982~2006年GIMMS NDVI和气象数据,探究中国草原区植被变化及对气候的响应。结果表明,近25 a中国草原区植被覆盖总体呈上升趋势,但季节变化空间差异明显。春季温度对温带典型草原、高寒草甸草原和高寒典型草原植被生长有重要影响,而夏季和秋季温度同样对高寒草甸草原影响显著;夏季降水增多能明显促进夏季温带荒漠草原植被生长。除8月份以外,温带草原5~9月NDVI均与前一个月降水显著正相关;在生长季内,高寒草原NDVI与同期温度显著正相关,但8月份除外。此外高寒草原植被在生长最旺盛时期对降水变化存在1~3个月滞后期。     

东北农牧交错区水分条件及其对植被分布的影响

水分条件是决定植物生长，分布的主要因子之一，也是生态学和地理学研究所关注的一个基本问题，本文依据最新的数据资料对东北农牧交错区水分条件的基本特征进行了分析，以三维图形表达了湿度指数的空间分布格局；对典型站点的年干燥度以及在年内的变化进行了分析；通过Kira指数，湿度指数和NDVI植被指数说明了农牧交错区植物生长，分布与水分条件的关系。     

Annual and seasonal variation of NDVI explained by current and previous precipitation across Northern Patagonia

Temporal variation of aboveground net primary production (ANPP) of arid ecosystems has been associated with precipitation regimes with different results. The objective of this paper was to characterize the relationship between interannual variation of annual and seasonal Normalized Difference Vegetation Index (NDVI), as a surrogate for ANPP, and precipitation in the steppes of Northern Patagonia. In 11 sites encompassing a wide range of conditions and vegetation physiognomies, we studied a 20-year monthly data set of NDVI and precipitation. We took into account the precipitation of current, as well as previous periods of variable length. Interannual variation of annual NDVI was little correlated with annual precipitation, either current or previous. In contrast, it was highly and widely correlated with precipitation accumulated during a few months of the previous growing season. Interannual variation of seasonal NDVI was little correlated with current seasonal precipitation. In contrast, it was significantly correlated with precipitation accumulated during previous periods of variable length according to the season and site under consideration. NDVI was more tightly coupled with precipitation in drier ecosystems. Lags of response between NDVI and precipitation provide an opportunity for forecasting ANPP and suggest even longer lags between climatic variation and herbivore performance.     

中国东部植被NDVI对气温和降水的时空响应(英文)

Temporal and spatial response characteristics of vegetation NDVI to the variation of temperature and precipitation in the whole year,spring,summer and autumn was analyzed from April 1998 to March 2008 based on the SPOT VGT-NDVI data and daily temperature and precipitation data from 205 meteorological stations in eastern China.The results indicate that as a whole,the response of vegetation NDVI to the variation of temperature is more pronounced than that of precipitation in eastern China.Vegetation NDVI maxi...     

Temporal and spatial response of vegetation NDVI to temperature and precipitation in eastern China

Temporal and spatial response characteristics of vegetation NDVI to the variation of temperature and precipitation in the whole year, spring, summer and autumn was analyzed from April 1998 to March 2008 based on the SPOT VGT–NDVI data and daily temperature and precipitation data from 205 meteorological stations in eastern China. The results indicate that as a whole, the response of vegetation NDVI to the variation of temperature is more pronounced than that of precipitation in eastern China. Vegetation NDVI maximally responds to the variation of temperature with a lag of about 10 days, and it maximally responds to the variation of precipitation with a lag of about 30 days. The response of vegetation NDVI to temperature and precipitation is most pronounced in autumn, and has the longest lag in summer. Spatially, the maximum response of vegetation NDVI to the variation of temperature is more pronounced in the northern and middle parts than in the southern part of eastern China. The maximum response of vegetation NDVI to the variation of precipitation is more pronounced in the northern part than in the middle and southern parts of eastern China. The response of vegetation NDVI to the variation of temperature has longer lag in the northern and southern parts than in the middle part of eastern China. The response of vegetation NDVI to the variation of precipitation has the longest lag in the southern part, and the shortest lag in the northern part of eastern China. The response of vegetation NDVI to the variation of temperature and precipitation in eastern China is mainly consistent with other results, but the lag time of vegetation NDVI to the variation of temperature and precipitation has some differences with those results of the monsoon region of eastern China.     

The temporal and spatial relationship between NDVI and climatological parameters in Colorado

This paper describes the spatial and temporal relationship between AVHRR/NDVI (Normalized Difference Vegetation Index) and climatological parameters (temperature and precipitation), which, in some sense, is influenced by topographical factors and land-cover types in Colorado. The correlation coefficients and partial correlation coefficients have been computed pixel by pixel over Colorado in order to analyze the relationship. The temporal variation and correlation of AVHRR/NDVI, temperature and precipitation were analyzed with a sampling method. The study reveals that there exists a close correspondence between monthly NDVI and temperature, which has strong impact from temperature on the changes of NDVI in Colorado. The spatial changes of NDVI are not influenced obviously by the precipitation since these two variables are different from each other in time series in Colorado. The study clearly revealed the spatial variation and its distribution patterns of relationship between NDVI and climatic parameters (temperature and precipitation) in Colorado.     

The temporal and spatial relationship between NDVI and climatological parameters in Colorado

1 Introduction In recent years, many researchers have demonstrated that there are essential and evident correlations between NDVI and climatological parameters (temperature and precipitation). The analysis of correlation between climate forces and time-integrated NDVI over US Northern and Central Great Plains suggested that spatial and temporal variation of precipitation and potential evapotranspiration and growing degree days in growing season are the most important control on grassland…     

青藏高原中东部水热条件与NDVI的空间分布格局

青藏高原受大气环流和地势格局的共同作用,水热条件及植被空间分布呈现独特的三维地带性特征。但是青藏高原范围广、地势起伏大,水热条件及植被空间分布具有明显区域差异。本文利用青藏高原中东部100个气象站1982²000年的降水、气温资料以及同期NO-AA AVHRR植被指数产品（NDVI）,分析水热条件及植被的空间分布特征。首先,设置经向、纬向海拔渐变样带,考察海拔对水热条件及NDVI空间分布的影响;然后,按500米海拔间隔进行站点分组,分析约束了海拔高差后的经纬位置对水热条件及NDVI空间分布的影响。研究表明:在青藏高原中东部由于海拔高差大,热量条件分布首先受海拔递减规律控制,其次才表现出因太阳辐射差异的纬度地带性;而降水分布则主要受水汽通道位置和方向的影响,北上水汽和东部偏南走向山脉是研究区降水经向特征的主要成因;指示植被状况的年均NDVI,则受水热组合的控制,其分布格局是二者的叠加与综合。     

2000-2012年祁连山植被覆盖变化及其与气候因子的相关性

研究祁连山地区植被覆盖变化及其与气候因子的响应关系对这一地区土地利用总体特征以及对区域及全球气候和环境变化都将产生深远的意义。利用2000-2012年美国国家航空航天局提供的MODIS NDVI数据并结合相应的气候资料,通过对逐像元信息的提取和分析,运用均值法、斜率分析法、相关分析法,研究了2000-2012年不同季节祁连山植被覆盖的时空变化及其与气候因子的相关性。结果表明:13 a来祁连山植被覆盖整体上呈增加趋势,其中春季植被改善最为明显,秋季次之;植被覆盖变化在不同季节都存在明显的空间差异;不同季节植被与气温、降水的时滞效应不尽相同;祁连山春季大部分地区NDVI与气温呈显著正相关,夏季NDVI与降水呈显著正相关,秋、冬季NDVI与降水、气温的相关性不明显。     

黄土高原植被降水利用效率对植被恢复/退化的响应

基于2000-2014年MODIS NDVI数据及气象数据,运用累计降水利用效率变化差异（CRD,cumulative rain use efficiency differences）估算模型和基于地形要素降水量插值法,探讨2000-2014年黄土高原RUE（降水利用效率rain use efficiency）对植被变化的响应,以期为黄土高原生态可持续发展提供数据支撑。结果表明：黄土高原大部分地区植被覆盖得以改善,其面积约占总面积的81%,区域边缘植被覆盖退化严重。黄土高原降水利用效率RUE与累计NDVI的相关性总体表现为“东南呈正相关,西北为负相关”的空间格局,全区相关系数以正相关为主。黄土高原CRD与植被变化趋势的相关性显著,其中,植被退化背景下,植被退化程度越严重,RUE越低;植被恢复背景下,RUE受“退耕还林还草”作用显著,2000-2005年,RUE呈上升趋势,2007年后,随着退耕还林还草政策的工作重心转移,RUE呈波动变化。     

藏东南三江并流核心区植被时空动态变化及其气候驱动力分析

植被生长状况及其分布对气候等影响因子的响应是当前生态学研究的热点之一。基于2000—2016年MODIS NDVI数据和气象数据,用Sen+Mann-Kendall等方法分析了藏东南三江并流核心区植被的时空变化及其与气候因子的关系。研究结果表明：① 该区植被覆盖整体趋于稳定,呈缓慢增加趋势,不同植被类型覆盖空间异质性明显。② 植被变化趋势结果显示植被覆盖变化以稳定不变和改善趋势为主,区域总体呈稳中向好态势。③ 相关分析表明植被NDVI增加主要与气候暖化有关,与降水量相关性较小。此外,人类活动对植被影响的双重性表现为：大多地区植被改善受生态工程和围栏禁牧政策影响,局部地区植被退化则与城镇化进程加快有关。研究结果揭示气温是影响植被格局的主要气候因子,了解影响植被变化及其驱动因素的空间变异性可为山地植被生态环境保护建设提供一定的科学依据。     

The relationship between NDVI and precipitation on the Tibetan Plateau

The temporal and spatial changes of NDVI on the Tibetan Plateau, as well as the relationship between NDVI and precipitation, were discussed in this paper, by using 8-km resolution multi-temporal NOAA AVHRR-NDVI data from 1982 to 1999. Monthly maximum NDVI and monthly rainfall were used to analyze the seasonal changes, and annual maximum NDVI, annual effective precipitation and growing season precipitation (from April to August) were used to discuss the interannual changes. The dynamic change of NDVI and the corre-lation coefficients between NDVI and rainfall were computed for each pixel. The results are as follows: (1) The NDVI reached the peak in growing season (from July to September) on the Tibetan Plateau. In the northern and western parts of the plateau, the growing season was very short (about two or three months); but in the southern, vegetation grew almost all the year round. The correlation of monthly maximum NDVI and monthly rainfall varied in different areas. It was weak in the western, northern and southern parts, but strong in the central and eastern parts. (2) The spatial distribution of NDVI interannual dynamic change was different too. The increase areas were mainly distributed in southern Tibet montane shrub-steppe zone, western part of western Sichuan-eastern Tibet montane coniferous forest zone, western part of northern slopes of Kunlun montane desert zone and southeastern part of southern slopes of Himalaya montane evergreen broad-leaved forest zone; the decrease areas were mainly distributed in the Qaidam montane desert zone, the western and northern parts of eastern Qinghai-Qilian montane steppe zone, southern Qinghai high cold meadow steppe zone and Ngari montane desert-steppe and desert zone. The spatial distribution of correlation coeffi-cient between annual effective rainfall and annual maximum NDVI was similar to the growing season rainfall and annual maximum NDVI, and there was good relationship between NDVI and rainfall in the meadow and grassland with medium vegetation cover, and the effect of rainfall on vegetation was small in the forest and desert area.     

陕西MODIS/NDVI的区域分布和季节变化

利用MODIS数据研究植被指数的时空变化特征,可以较详细地反映不同类型植被在其生长周期内的长势情况,以及各类植被生长状况在空间上的过渡和差异性。利用2004年全年的MODIS资料,采用NDVI多时相最大值合成法（MVC）,生成了一年的月合成NDVI数据集产品,分析表明：①陕西MODIS/NDVI年平均值为0.39,变化范围在-0.54～0.85之间。NDVI的年内频率分布只有在冬季（1月）呈现单峰型,其他季节均表现为双峰型。②冬季陕西NDVI的分布南北差异较小;春季延安以北和延安以南差异明显;夏季和秋季NDVI 值的分布体现了陕北北部长城沿线风沙区、黄土高原丘陵沟壑区稀疏植被、陕北南部子午岭和黄龙山林区森林植被、关中农田植被、秦巴山地森林植被和农田植被以及它们的地表差异特征。③不同植被类型的NDVI季节变化差别显著,这种NDVI时间序列曲线如实地反映了各种类型植被的生长规律,并能区分它们在生长规律上的细微差别,这又为植被区划、农作物种植面积的遥感监测提供了理论和实践基础。     

青藏高原植被覆盖变化与降水关系

The temporal and spatial changes of NDVI on the Tibetan Plateau, as well as the relationship between NDVI and precipitation, were discussed in this paper, by using 8-km resolution multi-temporal NOAA AVHRR-NDVI data from 1982 to 1999. Monthly maximum NDVI and monthly rainfall were used to analyze the seasonal changes, and annual maximum NDVI, annual effective precipitation and growing season precipitation (from April to August) were used to discuss the interannual changes. The dynamic change of NDVI and the corre- lation coefficients between NDVI and rainfall were computed for each pixel. The results are as follows: (1) The NDVI reached the peak in growing season (from July to September) on the Tibetan Plateau. In the northern and western parts of the plateau, the growing season was very short (about two or three months); but in the southern, vegetation grew almost all the year round. The correlation of monthly maximum NDVI and monthly rainfall varied in different areas. It was weak in the western, northern and southern parts, but strong in the central and eastern parts. (2) The spatial distribution of NDVI interannual dynamic change was different too. The increase areas were mainly distributed in southern Tibet montane shrub-steppe zone, western part of western Sichuan-eastern Tibet montane coniferous forest zone, western part of northern slopes of Kunlun montane desert zone and southeastern part of southern slopes of Himalaya montane evergreen broad-leaved forest zone; the decrease areas were mainly distributed in the Qaidam montane desert zone, the western and northern parts of eastern Qinghai-Qilian montane steppe zone, southern Qinghai high cold meadow steppe zone and Ngari montane desert-steppe and desert zone. The spatial distribution of correlation coeffi- cient between annual effective rainfall and annual maximum NDVI was similar to the growing season rainfall and annual maximum NDVI, and there was good relationship between NDVI and rainfall in the meadow and grassland with medium vegetation cover, and the effect of rainfall on vegetation was small in the forest and desert area.     

云南省近20年植被动态变化遥感时序分析

植被动态变化监测是生态环境变化监测的重要内容。利用20年的AVHRR 8 km的NDVI数据集,研究了云南省的植被指数变化特征,结果表明:(1)云南省植被具有明显的季节差异和空间差异。植被总生长季节为5月上旬到10月中旬。滇西南地区植被覆盖度高,植被指数最早达到峰值,生长期较其他区域长,冬季植被指数最高。滇东北地区的NDVI值较其他区域变动幅度不大,但冬季植被指数在各区中属最低。滇中、滇东南、滇南、滇西生长季的开始各不一,滇东南最早4月中旬、滇中和滇南相近在5月中下旬、滇西最迟在7月上旬。近20年来云南省的全省的平均生长季已延长一旬,主要表现在春季提早一旬开始。(2)1982～2001年,云南省全区的植被指数有增加的趋势,植被覆盖略有上升。滇东北植被指数最低,滇西南植被指数最高。滇南、滇西、滇东南植被指数变动趋势与全区相类似,表现出植被指数增长的趋势。滇西北、滇中植被指数的变化幅度介于滇东北和全省植被指数变化曲线之间。滇东北植被指数变化曲线波动幅度不大,最低值出现在1984年,在1990年植被指数下降,在随后几年植被指数略有上升,但平均NDVI在全省范围内属最低。滇东南、滇南、滇西年植被指数变化与全省的波动幅度的相近,波动范围在0.02～0.08。全省、滇西南、滇东北、滇中、滇东南区域曲线走势相似,滇西和滇西北的曲线走势相似,波峰、波谷的出现年份极为相近。