克里雅河流域中游绿洲蒸散发的时空演变与驱动因素分析

蒸散发是评估荒漠绿洲水热循环的关键因素,其时空变化监测及驱动力研究可为水资源的精准调控与生态环境保护提供科学依据。以克里雅河流域中游绿洲地区为研究区域,本文基于Landsat遥感影像与SEBS模型分析了2010—2022年蒸散发的时空变化,通过蒸发皿实测数据和Penman-Monteith模型进行了估算结果的精度验证,并进一步探讨了蒸散发的影响因素。结果表明：(1)蒸散发的SEBS模拟值与蒸发皿观测值的相关系数和R²分别为0.93和0.87,RMSE为0.96 mm/d;与彭曼公式观测值的相关系数和R²分别为0.90和0.81,RMSE为0.64 mm/d。(2)2010—2022年的实际蒸散发呈下降趋势,其变化速率为14.75 mm/a;在春季、夏季和秋季呈下降趋势,在冬季则呈上升趋势。(3)蒸散发的空间异质性明显,高值主要集中在克里雅河沿岸附近,低值则分布在绿洲边缘地区的沙地;近13年整个研究区约有70.2%的像元呈无显著下降趋势,10.4%的像元呈显著下降趋势。(4)蒸散发与气温、气压、日照时数、地表温度和NDVI呈显著相关关系,与风速...     

数据驱动的蒸散发遥感反演方法及产品研究进展

蒸散发是水圈、大气圈和生物圈中水分循环和能量交换的纽带。在全球尺度上,蒸散发约占陆地降水总量的60%;作为其能量表达形式,潜热通量约占地表净辐射的80%。随着通量观测技术的发展,全球长期持续的观测数据得以获取和共享,近年来基于数据驱动的蒸散发遥感反演方法取得了较好的研究进展。本文针对数据驱动的蒸散发遥感反演方法和产品,从经验回归、机器学习和数据融合3个方面展开,对现有的研究进展进行了梳理、归纳和总结,并从驱动数据、反演方法、已有产品等方面指出目前仍存在的问题和不足。未来仍需开展数据驱动的高时空分辨率的蒸散发遥感反演方法的研究,有效考虑地表温度和土壤水分等可以指示地表蒸散发短期变化的重要信息,同时加强基于过程驱动的物理模型与数据驱动的模型的结合,使两类模型能互为补充、各自发挥所长,共同推动蒸散发遥感反演研究水平的进步。     

石羊河流域蒸散发量遥感估算及时空格局分析

根据能量平衡原理,采用MODIS图像数据反演石羊河流域的地表蒸散发(Evapotranspiration,ET),对石羊河流域1月、4月、7月和10月的日均ET进行了估算(1月的日ET为0.15～7.21 mm,4月的日ET为0.89～7.86 mm,7月的日ET为0.12 ～9.08 mm,10月的日ET为0.54～...     

黄河流域森林覆盖时空变化及驱动因素分析

为探究1990—2020年黄河流域森林覆盖时空变化及其驱动因素,本文基于土地覆盖、自然因素及人类活动数据,使用转移矩阵、Theil-Sen Median和Manna-Kendall趋势分析、地理探测器进行了研究。结果表明：(1)黄河流域森林覆盖范围扩大,覆盖面积增加近2万km²;(2)1990—2020年,黄河流域168个县的森林覆盖率呈增长趋势,仅两个县的森林覆盖率减少;(3)基于地理探测器的结果表明,短波辐射对森林覆盖分布解释力最大,交互探测表明,降雨和高程的交互作用对森林覆盖分布解释力最强。本文可为黄河流域生态环境高质量发展提供科学参考。     

兰州新区生态用地时空演变及驱动因素分析

研究生态用地的时空演变及驱动因素,可以为实现区域可持续发展与推动生态文明建设提供参考。因此,运用土地利用动态度、土地利用转移矩阵及GIS技术等方法,分析兰州新区2010—2018年生态用地时空演变及形成机理。研究表明,兰州新区生态用地时空变化显著,其驱动因素与政策导向密切相关。     

横断山区水源涵养时空变化及驱动因子研究

本研究以水量平衡方程为理论基础,结合GIS/RS技术和数理统计方法,以雅安市为研究区,从区域尺度评估其水源涵养,并分析了其时空变化特征,定量描述了驱动因子与水源涵养的关系。结果表明:研究区水源涵养在空间上总体呈辐散式分布,由中东部向其他方向递减;在时间上呈优化发展的趋势,年均水源涵养量增长率达5984万m^3/a;森林及湿地生态系统是研究区水源涵养的主体,涵养水量超过总涵养水量的70%;高程、坡度、地表温度对研究区水源涵养的综合影响最大。     

东北地区水稻分布的时空演变特征及驱动机制分析

研究水稻分布的时空演变特征及驱动机制,对优化农业生产结构至关重要.基于植被物候变化特征、地表水变化特征结合方法识别水稻的空间分布,获取了2001—2017年东北水稻空间分布图,并进行了水稻的时空演变特征及驱动机制研究.研究表明,2001—2017年东北地区水稻呈先略减后直线上升的特点,2017年水稻种植面积约300万h...     

江苏省城市土地利用效率时空演变及驱动因素分析

城市土地利用效率直接影响着城市的社会经济发展和城市居民的生活环境,本文利用DEA模型、ESDA统计指数模型以及Tobit回归分析模型,对江苏省2010—2016年13个地级市城市土地利用的静态和动态效率进行测度,并且对于其空间格局以及驱动机制进行了初步的研究。结果表明,在研究的时空区间内,该地区的土地利用效率整体较高,但土地利用效率地区差异明显,且城市土地利用效率呈现下降趋势,Malmquist值在全局上有着较强的正的空间自相关。     

农田水分生产率估算方法及应用

水分生产率是评价农业灌溉用水管理水平和节水效果的一个重要指标.本文利用遥感数据定量估算了流域平原区的蒸散量和干物质量,采用经验的收获指数计算了海河流域2003-2008多年平均水分生产率.通过在水资源三级分区的统计结果分析表明：遥感估算的水分生产率可以反映单方水产出的空间差异,海河流域平原平均水分生产率为0.99kg/m3,变化范围为0.02-2.13kg/m3,总体水平较低,南北差异较大。通过ET,产量和水分生产率关系的分析表明水分生产率与产量线性相关(R＝0.97),提高产量将一直是流域提高水分生产率的重要研究方向。水分生产率与产量随ET变化均为先线性增加后减小的特点,在两季作物区当年耗水量在335-575mm范围变化时,水分是影响产量和水分产出效益的关键因子,要着重提高中低产区域的水分生产率; 当耗水量超过575mm,水分不是唯一的限制因子,以提高作物的收获指数为重点。     

河西走廊土地利用时空变化特征及驱动因素分析

利用2009—2019年河西走廊土地利用现状年度变更调查数据,采用土地利用变化速率、土地利用动态度、核密度等要素,对河西走廊土地利用10年间变化的特征进行分析,探讨土地利用变化的驱动因素,为河西走廊土地资源合理开发和生态环境保护提供科学依据。     

Effects of water and heat on growth of winter wheat in the North China Plain

The North China Plain (NCP) was selected as the study area and the effects of water and heat were analysed to determine the dominant factor affecting winter wheat growth. The mean, minimum and maximum temperatures, precipitation and soil moisture data were selected to analyse the correlations between the leaf area index (the growth indicator) and these factors using long time series half-monthly data (2–5 months) (from 1982 to 2010). The results showed that temperature was the main factor affecting the growth of winter wheat in the NCP. The growth of winter wheat had weak correlations with precipitation and soil moisture and the influence of water on winter wheat growth was smaller than the influence of heat. In the northern part of the NCP, mainly including the north-west region of Shandong Province and the southern region of Hebei Province, irrigation was necessary in late February and early March.     

Estimation of regional evapotranspiration over the North China Plain using geostationary satellite data

Data from the first operational Chinese geostationary satellite Fengyun-2C (FY-2C) satellite are applied in combination with Moderate Resolution Imaging Spectroradiometer (MODIS) satellite products for the assessment of regional evapotranspiration over the North China Plain. The approach is based on the improved triangle method, where the temperature–vegetation index space includes thermal inertia. Two thermal infrared channels from FY-2C are used to estimate surface temperature (Ts) based on a split window algorithm originally proposed for the MSG-SEVIRI sensor. Subsequently the high temporal resolution of FY-2C data is exploited to give the morning rise in Ts. Combined with the 16 days composite MODIS vegetation indices product (MOD13) at a spatial resolution of 5 km, evaporative fraction (EF) is estimated by interpolation in the ΔTs–NDVI triangular-shaped scatter space. Finally, regional actual evapotranspiration (ET) is derived from the evaporative fraction and available energy estimated from MODIS surface albedo products MCD43. Spatial variations of estimated surface variables (Ts, EF and ET) corresponded well to land cover patterns and farmland management practices. Estimated ET and EF also compared well to lysimeter data collected for the period June 2005–September 2007. The improved triangle method was also applied to MODIS products for comparison. Estimates based on FY-2C products proved to provide slightly better results than those based on MODIS products. The consistency of the estimated spatial variation with other spatial data supports the use of FY-2C data for ET estimation using the improved triangle method. Of particular value is the high temporal frequency of image acquisitions from FY-2C which improves the likelihood of obtaining cloud free image acquisitions as compared to polar orbiting sensors like MODIS.     

遥感定量反演华北平原地区冬小麦含水量

针对现有植被水分反演算法在华北平原地区适用性差、反演精度低、不能实施有效监测的问题,该文基于地面实测冬小麦植被含水量(VWC)数据,基于归一化型和比值型植被水分指数这两种常见的指数类型,提出调节植被水分指数以削弱土壤背景的影响,使用多个波段反射率数据反演VWC,提高拟合精度80%以上,发展适用于华北平原的农作物水分含量反演模型。拟合冬小麦植被含水量的决定系数为0.51,均方根误差为0.95(kg·m^-2)。结果表明:调节植被水分指数能够削弱土壤背景影响,大幅度提高植被水分反演精度;同一种指数计算形式中,在水汽吸收谷内,基于更长波段反射率的植被水分指数反演精度更高;归一化型和比值型植被水分指数在反演精度方面无明显优劣,归一化型植被水分指数反演精度。     

多源卫星遥感的华北平原大气NO2浓度时空变化

为探讨1996年以来华北平原对流层NO_2柱浓度变化的空间特征,基于GOME、SCIAMACHY和OMI卫星传感器的监测数据,以SCIAMACHY的NO_2柱浓度为基准,根据建立的GOME和SCIAMACHY,SCIAMACHY和OMI之间的相关关系,校正GOME和OMI监测的NO_2数据;利用线性正弦曲线模型拟合方法研究1996年—2016年长时间序列华北平原对流层NO_2变化的空间分布特征。结果显示,华北平原对流层NO_2浓度自1996年开始持续上升,到2011年达到最高值,然后呈现下降趋势。该变化趋势主要受经济发展和环保政策的双重影响。1996年—2011年,NO_2柱浓度高值区分布在北京市、天津市、河北唐山市和保定市、山东德州市和济南市、安徽滁州市以及江苏南京市、常州市和无锡市,并且具有较高增长率;2012年—2016年NO_2柱浓度平均值远高于1996年—2011年NO_2柱浓度平均值,高值地区范围扩大,分布在河北南部、河南北部和山东西部,但华北平原地区NO_2柱浓度均呈现负增长,表明"十二五"规划提出的大气环保政策取得了显著成效。同时,对流层NO_2柱浓度可以反映典型环保事件如北京奥运会、国庆阅兵和南京青奥会时期大气环保政策的实施效果。     

Multiple intra-urban land use simulations and driving factors analysis: a case study in Huicheng,China

Simulations of intra-urban land use changes have gradually attracted more attention as these approaches are extremely helpful in regard to decision making and policy formulation. While prior studies mostly focused on methods of developing intra-urban level simulations, very little research has been conducted explain the factors driving intra-urban land use change. Urban planners are highly concerned with how inner-city structures are formed and how they function. Here, to simulate multiple intra-urban land use changes and to identify the contribution of different driving factors, we developed a random forests (RF) algorithm-based cellular automata (CA) simulation model. In this study, the model applied diverse categories of spatial variables, including traffic location factors, environmental factors, public services, and population density, as the driving factors to enhance our understanding of the dynamics of internal urban land use. The CA model was tested using data from the Huicheng district of Huizhou city in the Guangdong province of China. The Model was validated using actual historical land use data from 2000 to 2010. By applying the validated model, multiple intra-urban land use maps were simulated for 2015. Simultaneously, spatial variable importance measures (VIMs) were calculated by using the out-of-bag (OOB) error estimation approach of the RF algorithm. Based on the calculation results, we assessed and analysed the significance of each intra-urban land use driver for this region. This study provides urban planners and relevant scholars with detailed and targeted information that can aid in the formulation of specific planning strategies for different intra-urban land uses and support the future evolution of this area.     

湖北省植被净初级生产力时空变化特征及其影响因素分析

基于改进的光能利用率模型,本文利用MODIS数据和同期气象数据估算分析了湖北省2001—2012年间植被净初级生产力(NPP)的时空变化特征并借助多元统计分析方法定量探究自然因素(气温、降水量、太阳辐射)和人为因素(土地覆被/土地利用、粮食播种面积、粮食产量、人口数量)对NPP变化的影响.结果表明:1)湖北省NPP呈波...     

Responses of global terrestrial water use efficiency to climate change and rising atmospheric CO2 concentration in the twenty-first century

Terrestrial ecosystems play a significant role in global carbon and water cycles because of the substantial amount of carbon assimilated through net primary production and large amount of water loss through evapotranspiration (ET). Using a process-based ecosystem model, we investigate the potential effects of climate change and rising atmospheric CO₂ concentration on global terrestrial ecosystem water use efficiency (WUE) during the twenty-first century. Future climate change would reduce global WUE by 16.3% under high-emission climate change scenario (A2) and 2.2% under low-emission climate scenario (B1) during 2010–2099. However, the combination of rising atmospheric CO₂ concentration and climate change would increase global WUE by 7.9% and 9.4% under A2 and B1 climate scenarios, respectively. This suggests that rising atmospheric CO₂ concentration could ameliorate climate change-induced WUE decline. Future WUE would increase significantly at the high-latitude regions but decrease at the low-latitude regions under combined changes in climate and atmospheric CO₂. The largest increase of WUE would occur in tundra and boreal needleleaf deciduous forest under the combined A2 climate and atmospheric CO₂ scenario. More accurate prediction of WUE requires deeper understanding on the responses of ET to rising atmospheric CO₂ concentrations and its interactions with climate.     

Shrinkage and fragmentation of marshes in the West Songnen Plain,China, from 1954 to 2008 and its possible causes

Agricultural development under climatic variations has resulted in substantial loss of marshes in the West Songnen Plain in the past decades. In this paper, the shrinkage and fragmentation process of marshes and its possible causes in the West Songnen Plain from 1954 to 2008 were explored using historical topographic maps and remote sensing data. Results indicated that the West Songnen Plain underwent considerable shrinkage and fragmentation of marshes in that same period. Marshes occupied 6404 km² in 1954, but this area has decreased by 74% in the past 54 years. The average annual decrease rate of marshes was 88 km² per year. Meanwhile, the number of marsh patches decreased from 1411 to 514, and the mean patch size decreased from 454 to 320 ha. Cropland and salinized wasteland were the two main land use types into which marshes were converted. During the same period, grassland decreased by 54%, cropland increased by 22%, and salinized wasteland expanded by 612%. A significant increase in air temperature and index of dryness was found in the study region, along with decreased precipitation, thereby affecting the marsh systems through the changing hydrological regimes. On the other hand, population, gross domestic product, and livestock number increased considerably as marshes shrank and became fragmented. Governmental policy changes played a key role in land use transformations in the study region.     

中国雾霾分布及其组成相关性分析

雾霾天气由于其对人体健康及交通能见度的极大影响而受到广泛关注。在收集相关污染物与气象数据基础上,基于GIS技术及最小二乘法和地理加权回归模型分析了我国2014年1月雾霾空间分布特征及其组成要素的相关性。研究表明,2014年1月我国各省会城市基本都受到雾霾影响,其中华北地区最为显著,华东、华南沿海城市具有一定的相似性;西南部地区大部雾霾污染明显小于其他地区。从雾霾物质组成上看,PM_(2.5)与PM_(10)、CO、NO_2和SO_2之间存在微妙关系,随着其他污染物的增加,PM_(2.5)数值也会随之增大,其中PM_(10)和CO对PM2.5的影响是显著的。从研究方法上看,利用地理加权回归建模方法对雾霾及其组成成份相关性研究的效果(84%)略好于最小二乘法的分析效果(82.59%)。本研究可为了解雾霾空间分布特征及分析其相关影响因素提供参考。