近14a新疆南疆绿洲地区地表蒸散与干旱的时空变化特征研究

利用2001—2014年MOD16蒸散产品数据、MOD13植被[WTBX]NDVI[WTBZ]数据以及常规气象资料,基于植被指数、地表净辐射、气温优化改进混合型线性双源遥感蒸散模型,拟合地表蒸散分析实际蒸散（ET）、潜在蒸散（PET）时空动态变化特征,结合气象站实测蒸发皿数据验证MOD16数据在绿洲地区的适用性。进一步定义蒸散干旱指数（EDI）并计算△EDI进行研究区干旱特征分析,为大面积特殊地形蒸散估算研究和干旱监测提供一定依据。结果表明：（1） MOD16产品数据与研究区实测蒸发皿数据的相关性很好,通过0.01显著性检验,基于MOD16数据估算南疆绿洲地区蒸散量检验可行。（2） 2001—2014年均蒸散量总体变化不大,四季差异明显,ET与PET空间变化趋势相反;ET、PET年均差值较大,绿洲地区地表缺水情况严重。（3） EDI指数绿洲地区年均值总体偏大,△EDI对旱情的反映和干旱程度的判断比较可靠。     

基于GLASS数据估算中国陆表净辐射及其空间分布分析

地表辐射收支是能量循环的重要参数,影响着地球水热平衡,是全球气候变化研究的重要方面。多数研究利用MODIS数据估算地表辐射收支,模型输入参数复杂。综合利用GLASS数据、MODIS数据和地面实测数据,采用Bisht等提出的净辐射估算方法,制订一种简单的地表辐射收支估算方案,分别计算2010年1-12月中旬卫星过境时刻中国陆表净辐射的最大值。通过改进的正弦模型将估算结果转换为日最大地表净辐射,并利用地面实测日最大净辐射值对估算结果进行了验证。研究表明：综合利用GLASS数据、MODIS数据和地面实测数据建立的地表辐射收支模型能够很好地模拟中国陆表净辐射的分布,与地面实测日最大净辐射值具有较好的一致性,平均误差为27.21 W?m^-2,克服了利用其他遥感数据估算地表辐射收支输入参数复杂,数据量大的缺点,适用于大尺度地表陆表辐射收支研究。     

GPS可降水汽与MODIS可降水汽回归性分析

地基GPS可反演大气可降水汽,为气象预报提供高精度的大气水汽数据。然而GPS观测仅可以提供离散点的水汽值,MODIS却可以提供空间连续变化的水汽值,但MODIS水汽反演误差的存在使其不能满足气象预报的精度要求,因此两种遥感水汽的融合研究尤为必要。基于此,该文利用西安2006年7月-2009年7月7期GPS观测数据、地面气象实测数据和对应的MODIS数据,研究了GPS与MODIS两种遥感水汽间的回归关系,在考虑水汽的季节性变化的基础上建立了两者的回归模型,并由此建立了直接对MODIS反演水汽值的校正模型。根据多个经验模型,确定了西安GPS湿延迟与GPS可降水汽的比值:夏季取6.00、冬季取6.52。     

基于MODIS遥感数据地表水汽压估算

地表水汽压是大气科学、水文学等多项研究中的一个重要输入参数.鉴于常规观测方法对于地面气象站点依赖性强且空间不连续的缺点,采用MODIS遥感数据对海河流域的日平均地表水汽压进行估算.通过相关分析得出日平均地表水汽压与MOD07低空可降雨量数据具有很强的相关性,并通过对比采用二次曲线进行建模.选取2009年1-4月数据对二次曲线模型的验证结果表明,估箅结果与实测日平均地表水汽压1∶1曲线的相关系数R2为0.83.本文的研究结果提供了一种实用的基于遥感数据估算日平均地表水汽压的方法.     

利用卫星数据估算南大洋海-气CO2通量的展望

本文简述了南大洋在全球碳循环系统中的重要作用以及极地海域海洋CO2通量现场实测数据调查的局限性和存在问题,借鉴国外学者在大洋利用卫星数据估算海-气CO2通量的研究成果,结合我国在南极积累的二十多年的大洋考察资料,展望我国在南大洋进行相关碳通量估算的研究前景。总的基本思路是:从海表层水CO2分压和其相应的调控因子之间推导出经验公式,通过最佳的插值方式由卫星遥感数据外推整个计算海域的CO2数据场,与实测数据做比较,计算碳通量。     

基于MODIS影像的土地覆被分类研究——以京津冀地区为例

在全球变化研究中,如何快速、准确获取土地覆被信息对该项研究有着至关重要的作用.随着遥感科学的不断发展和应用领域的深入,研究者可以利用遥感影像进行土地覆被分类研究,并且具有准确、快速、自动化等优点.本文利用MODIS数据具有的多光谱、多时相特点,以京津冀地区为例,选取2013 年全年16-day 的MOD13Q1/EVI时间序列数据、2013 年5 月份一期的MOD09Q1(1、2 波段)和MOD09A1(3-7 波段)产品,并运用时间序列谐波分析法对全年MOD13Q1/EVI 时间序列数据进行去云、去噪的平滑重建处理,使其数据更能反映物候周期性变化规律.选择谐波分析后的全年MOD13Q1/EVI 时间序列数据、MODIS数据的1-7 波段地表反射率和NDWI(归一化差异水体指数)、MNDWI(改进归一化差异水体指数)和NDSI(土壤亮度指数),构建了3 种特征变量组合方案的CART决策树,分别进行京津冀地区的土地覆被分类研究.结果表明:方案一(全年EVI 的23 个时相)、方案二(方案一+MOD09 的1-7 波段地表反射率)和方案三(方案二+MNDWI+NDSI+NDWI)的总体分类精度分别达到86.70%、89.98%、91.34%,Kappa系数分别为84.94%、88.66%、90.20%.研究表明,仅利用MODIS遥感影像自身多种分类特征和决策树方法对宏观土地覆被分类就可达到较高精度,显示了本文分类方法在实践中的可行性及MODIS数据在区域尺度土地覆被分类研究方面的优势与潜力.     

基于修正的GHG-RA模型的三峡库区甲烷排放通量估算

利用以往研究中三峡库区的24个监测点的甲烷排放通量实测数据及其年平均气温和降水量数据,对温室气体排放风险评估模型(greenhouse gas risk assessment tool,GHG-RA)的系数进行了修正;利用修正的GHG-RA模型,估算了三峡库区24个监测点的甲烷排放通量;对2018～2117年期间三峡库区的平均甲烷排放风险进行了评价。研究结果表明,利用修正的GHG-RA模型估算的24个监测点的甲烷排放通量的平均值为0.222 mg/(m2·h),与实测值的均方根误差和平均偏差分别为0.12 mg/(m2·h)和0.32 mg/(m2·h);估算的2018～2117年期间三峡库区的平均甲烷排放通量为0.255 mg/(m2·h),甲烷排放风险为中等排放风险。     

不同类型生态系统水热碳通量的监测与研究

亚太地区环境革新战略项目(APEIS) 在中国5种主要生态系统类型区(草地: 海北、耕地: 禹城、稻田: 桃源、林地: 千烟洲、荒漠: 阜康) 建立了一个以连续观测能量、水分和碳素通量为中心,包括气象、水文、土壤、植被等各项生态要素的监测网络系统,被称之为APEIS-FLUX系统。作者首先对APEIS-FLUX系统的观测数据进行了初步分析,表明该系统稳定可靠,它可以实时地提供高质量、高精度、长期而连续的通量及生态要素的观测数据。对数据的比较清楚地反映出了不同生态系统类型区的水热碳通量的差异性。其次,利用APEIS-FLUX数据对美国航空航天局(NASA) 的MODIS数据产品进行比较验证后发现,除部分产品如地表面温度(MOD11) 等与观测数据较吻合以外,大部分数据产品如土地覆盖(MOD12),叶面积指数(MOD15) 和光合速率与净第一性生产力(MOD17) 等都与观测数据相差深远,有必要对其处理程序和模式进行修正。为此,我们利用APEIS-FLUX的数据作为MOD15和MOD17的生成模型(BIOME-BGC) 的输入数据,并对该模型的有关参数进行了修订。结果表明,该模式在通过修正后,可以很好地模拟植被的生长过程及其相应的水热碳循环过程。     

遥感反演土壤蒸发/植被蒸腾二层模型在华北地区的应用

利用一种可操作的地表蒸散遥感反演二层模型,以我国华北平原为研究区,选择2004年的3月至6月华北地区主要农作物冬小麦的生长季节作为研究时段,利用MODIS遥感卫星数据,结合地面130多个气象台站的空气温湿度实测数据,实现了土壤蒸发和植被蒸腾的反演。采用国家生态网络禹城综合试验站利用涡度相关系统观测的地表总蒸散半小时平均的数据进行了模型验证,结果表明模型估算的地表可利用能量与地面实测数据的相关系数可以达到0.92,均方差为30.4w.m^-2;模型估算的地表总蒸散值与地面实测数据的相关系数为0.85,均方差为21.3 w.m^-2,由此证明了模型的可用性。     

利用Landsat8数据估算干旱区晴天太阳瞬时和日间净辐射

地表净辐射是地球表面的短波和长波辐射输入和输出通量辐射平衡的结果,也是地表蒸散与水热平衡研究中非常重要的方面。利用2014年8月下旬的Landsat8遥感影像,采用BISHT等提出的净辐射估算方法,首先通过计算瞬时大气传输率、瞬时短波太阳辐射和下行长波辐射得到了短波辐射与长波辐射的估算值,并进一步通过计算地表反照率等得到了瞬时净辐射和日均净辐射,最后利用地面实测净辐射值对估算结果进行了验证。研究表明：利用分辨率较高的Landsat8数据和部分气象参数能够很好地模拟该地区晴天的瞬时和日间净辐射的分布,并且与地面实测净辐射值具有较好的一致性,平均误差为14.5 W·m^-2。研究弥补了利用其他遥感数据估算地表辐射参数复杂、精度偏低的缺陷,可以适用于干旱地区的晴天瞬时和日间净辐射值的估算,并且能够有效的提高估算精度。     

一个预测冬小麦根系层储水量的概念性模型

基于对SPAC系统的认识,以1995～1996年北京市水利科学研究所永乐店试验站和1993～1994年中国科学院禹城综合试验站冬小麦生长季土壤-作物-大气田间观测数据,对冬小麦根系层水量平衡的概念性模型进行参数确定和实验验证。研究结果表明:本文采用的根系层储水量的预测模型的模拟值与实测值吻合较好,且模型参数较少,形式简单,便于生产实践应用,但是具体的参数须通过田间试验获得。     

基于TVDI的藏北地区土壤湿度空间格局

利用2010年DOY 209期的Terra/MODIS 16 d合成的植被指数(EVI)产品数据MOD13A2和8d天合成的地表温度(LST)产品数据MOD11 A2,构建LST-EVI特征空间,从而得到了条件温度植被干旱指数TVDI反映的藏北土壤湿度空间分布图.结合野外同步土壤表层水含量测试数据,二者表现出较好的相关...     

Monitoring and simulation of water, heat, and CO2 fluxes in terrestrial ecosystems based on the APEIS-FLUX system

The Integrated Environmental Monitoring (IEM) project, part of the Asia-Pacific Environmental Innovation Strategy (APEIS) project, developed an integrated environmental monitoring system that can be used to detect, monitor, and assess environmental disasters, degradation, and their impacts in the Asia-Pacific region. The system primarily employs data from the moderate resolution imaging spectrometer (MODIS) sensor on the Earth Observation System- (EOS-) Terra/Aqua satellite, as well as those from ground observations at five sites in different ecological systems in China. From the preliminary data analysis on both annual and daily variations of water, heat and CO2 fluxes, we can confirm that this system basically has been working well. The results show that both latent flux and CO2 flux are much greater in the crop field than those in the grassland and the saline desert, whereas the sensible heat flux shows the opposite trend. Different data products from MODIS have very different correspondence, e.g. MODIS-derived land surface temperature has a close correlation with measured ones, but LAI and NPP are quite different from ground measurements, which suggests that the algorithms used to process MODIS data need to be revised by using the local dataset. We are now using the APEIS-FLUX data to develop an integrated model, which can simulate the regional water, heat, and carbon fluxes. Finally, we are expected to use this model to develop more precise high-order MODIS products in Asia-Pacific region.     

基于亚太地区环境综合监测的陆地生态系统中水、热和二氧化碳的监测与模拟

The Integrated Environmental Monitoring (IEM) project, part of the Asia-Pacific Environmental Innovation Strategy (APEIS) project, developed an integrated environmental monitoring system that can be used to detect, monitor, and assess environmental disasters, degradation, and their impacts in the Asia-Pacific region. The system primarily employs data from the moderate resolution imaging spectrometer (MODIS) sensor on the Earth Observation System- (EOS-) Terra/Aqua satellite,as well as those from ground observations at five sites in different ecological systems in China. From the preliminary data analysis on both annual and daily variations of water, heat and CO2 fluxes, we can confirm that this system basically has been working well. The results show that both latent flux and CO2 flux are much greater in the crop field than those in the grassland and the saline desert, whereas the sensible heat flux shows the opposite trend. Different data products from MODIS have very different correspondence, e.g. MODIS-derived land surface temperature has a close correlation with measured ones, but LAI and NPP are quite different from ground measurements, which suggests that the algorithms used to process MODIS data need to be revised by using the local dataset. We are now using the APEIS-FLUX data to develop an integrated model, which can simulate the regional water,heat, and carbon fluxes. Finally, we are expected to use this model to develop more precise high-order MODIS products in Asia-Pacific region.     

Monitoring and simulation of water, heat,and CO2 fluxes in terrestrial ecosystems based on the APEIS-FLUX system

1IntroductionInJune1992,theworldsummitorganizedbytheUnitedNations,withparticipantsincludingnationalleadersfromaroundtheworld,concludedwithAgenda21(UnitedNations,1992),theRioDeclarationonEnvironmentandDevelopment,inRiodeJaneiro.Thedeclarationpromptedcountr…     

Impacts of climate change on winter wheat growth in Panzhuang Irrigation District, Shandong Province

Global climate change has significant impacts on agricultural production. Future climate change will bring important influences to the food security. The CERES-Wheat model was used to simulate the winter wheat growing process and production in Panzhuang Irrigation District (PID) during 2011–2040 under B2 climate scenario based on the Special Report on Emissions Scenarios (SRES) assumptions with the result of RCMs (Regional Climate Models) projections by PRECIS (Providing Regional Climates for Impacts Studies) system introduced to China from the Hadley Centre for Climate Prediction and Research. The CERES-Wheat model was calibrated and validated with independent field-measured growth data in 2002–2003 and 2007–2008 growing season under current climatic conditions at Yucheng Comprehensive Experimental Station (YCES), Chinese Academy of Sciences (CAS). The results show that a significant impact of climate change on crop growth and yield was noted in the PID study area. Average temperature at Yucheng Station rose by 0.86℃ for 1961–2008 in general. Under the B2 climate scenario, average temperature rose by 0.55℃ for 2011–2040 compared with the baseline period (1998–2008), which drastically shortened the growth period of winter-wheat. However, as the temperature keep increasing after 2030, the top-weight and yield of the winter wheat will turn to decrease. The simulated evapotranspiration shows an increasing trend, although it is not very significant, during 2011–2040. Water use efficiency will increase during 2011–2031, but decrease during 2031–2040. The results indicate that climate change enhances agricultural production in the short-term, whereas continuous increase in temperature limits crop production in the long-term.     

冬小麦水分耗散特性与农业节水

本文根据中国科学院禹城综合试验站１９８６年－１９９６年蒸渗仪农田水分模拟试验资料统计；冬小麦全生育期耗水量可达４８２．５ｍｍ，缺水率可达６９．３％；冬小麦全生育不分耗散过程有两个明显的需水峰区和３个关键需水期，为实施节水灌溉提供了实验依据；冬小麦耗水量与环境因子有明显的相关关系，其统计规律可供地下水浅埋区区域灌溉预测参照应用。     

气候变化对山东省潘庄灌区冬小麦生长的影响(英文)

Global climate change has significant impacts on agricultural production.Future climate change will bring important influences to the food security.The CERES-Wheat model was used to simulate the winter wheat growing process and production in Panzhuang Irrigation District(PID) during 2011-2040 under B2 climate scenario based on the Special Report on Emissions Scenarios(SRES) assumptions with the result of RCMs(Regional Climate Models) projections by PRECIS(Providing Regional Climates for Impacts Studies) system introduced to China from the Hadley Centre for Climate Prediction and Research.The CERES-Wheat model was calibrated and validated with independent field-measured growth data in 2002-2003 and 2007-2008 growing season under current climatic conditions at Yucheng Comprehensive Experimental Station(YCES),Chinese Academy of Sciences(CAS).The results show that a significant impact of climate change on crop growth and yield was noted in the PID study area.Average temperature at Yucheng Station rose by 0.86℃ for 1961-2008 in general.Under the B2 climate scenario,average temperature rose by 0.55℃ for 2011-2040 compared with the baseline period(1998-2008),which drastically shortened the growth period of winter-wheat.However,as the temperature keep increasing after 2030,the top-weight and yield of the winter wheat will turn to decrease.The simulated evapotranspiration shows an increasing trend,although it is not very significant,during 2011-2040.Water use efficiency will increase during 2011-2031,but decrease during 2031-2040.The results indicate that climate change enhances agricultural production in the short-term,whereas continuous increase in temperature limits crop production in the long-term.