遥感估算热惯量研究的回顾与展望

热惯量是影响地表温度变化的一个重要因子,随着热红外数据反演地表温度算法的不断完善,遥感技术已 成为估算热惯量的主要手段。本文回顾了近些年来遥感估算热惯量研究的进展,对其中3 种主要方法即地表温度 日较差法、日出日落温差法及模型反演法进行了评述,重点讨论了地表温度日较差估算热惯量方法,并提出从加强 机理研究、尺度转换及采用多时相多光谱数据等方面进一步完善遥感估算热惯量方法、提高其估算精度的设想。     

桂西山地灾害的监测、预测及其对策

广西百色市是自然灾害频发的地区,降雨是激发山地灾害的关键因素。通过收集大量的地质灾害资料和气象资料,运用天气学、数值预报产品、MOS法等,结合卫星探测资料,建立各种地理环境和地质特征条件下山地灾害预警的气象模型和各种灾害等级的预警指标,并就山地灾害的监测与对策提出了一些建议和措施。     

Methods for calculating glacier area and length in a mountainous area based on remote-sensing data and a digital elevation model

In a mountainous region, the glacier area and length extracted form the satellite imagery data is the projected area and length of the land surface, which can’t be representative of the reality; there are always some errors. In this paper, the methods of calculating glacier area and length calculation were put forward based on satellite imagery data and a digital elevation model (DEM). The pure pixels and the mixed pixels were extracted based on the linear spectral un-mixing approach, the slop of the pixels was calculated based on the DEM, then the area calculation method was presented. The projection length was obtained from the satellite imagery data, and the elevation differences was calculated from the DEM. The length calculation method was presented based on the Pythagorean theorem. For a glacier in the study area of western Qilian Mountain, northwestern China, the projected area and length were 140.93 km2 and 30.82 km, respectively. This compares with the results calculated by the methods in this paper, which were 155.16 km2 and 32.11 km respectively, a relative error of the projected area and length extracted from the LandSat Thematic Mapper (TM) image directly reach to -9.2 percent and -4.0 percent, respectively. The calculation method is more in accord with the practicality and can provide reference for some other object’s area and length monitoring in a mountainous region.     

基于卫星热红外辐射信息的新疆强震震例分析

利用NOAA-14极轨气象卫星红外波段的探测数据,对遥感数据进行多种处理,采用影像目视解释和提取地表辐射亮温值的方法,对新疆的三次强震进行分析,结果发现在地震前都出现了热红外异常,这为地震监测提供了一个重要信息。     

青藏高原西部地面反射率的日变化以及与若干气象因子的关系

根据1997年10月至1998年11月青藏高原西部改则和狮泉河两个自动气象站连续观测的大气、辐射和土壤资料,在分析高原西部地面反射率冬、夏季日变化特征的基础上,重点研究了地面反射率与土壤和大气若干重要因子(如土壤湿度、土壤温度、空气相对湿度、空气温度)的关系。研究结果有助于改进气候模式和卫星遥感中高原地面反射率的参数化方案。     

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。     

Mapping Systems and GIS: A Case Study using the Ghana National Grid

The problem of incompatible projections and conversion between mapping systems is of general concern to those involved in the collection of natural resources data. The Ghana National Grid (GNG) is an example of a mapping system that is not defined in image processing and GIS software and for which the transformation parameters are not readily available in the literature. Consequently, integrating GNG topographic map data within a GIS with data derived from other sources can be problematic. In this paper a practical solution for deriving the required transformation parameters to convert from the World Geodetic System of 1984 (WGS84) to the GNG system is demonstrated. The method uses a single geodetic control point, available 1:50 000 topographic maps and a SPOT satellite panchromatic image geo-referenced to GNG. The resultant parameters are applied to road survey data in Universal Transverse Mercator (UTM) format for overlay with the SPOT image. Despite the approximations made in applying the method, when compared against official estimates of the datum transformation parameters, this relatively simple procedure resulted in estimates that appear acceptable in regard to combining data sets at a nominal scale of 1:50000.     

Thermal Remote Sensing of Near Surface Environmental Variables: Application Over the Oklahoma Mesonet

Many recent studies have applied satellite remote sensing data to large‐scale hydrologic and biospheric modeling. It is widely accepted that the thermal infrared observations from the Advanced Very High Resolution Radiometer (AVHRR) have the potential to estimate land surface conditions, such as surface temperature, near surface air temperature, and near surface water vapor. In this study, algorithms to estimate all three variables are presented and applied to an area covering the state of Oklahoma for a six day period in August, 1994. The results were validated using ground observations from the 111 station Oklahoma Mesonet. Validation of the remote sensing algorithms with Mesonet observations produced comparable results to previous validation studies. In addition, the validation process revealed inadequacies in thermal modeling that had not been detected in previous validation studies leading to the development of a new approach to estimate atmospheric water vapor.     

Beyond “Lawn People”: The Role of Emotions in Suburban Yard Management Practices

Many recent studies have applied satellite remote sensing data to large-scale hydrologic and biospheric modeling. It is widely accepted that the thermal infrared observations from the Advanced Very High Resolution Radiometer (AVHRR) have the potential to estimate land surface conditions, such as surface temperature, near surface air temperature, and near surface water vapor. In this study, algorithms to estimate all three variables are presented and applied to an area covering the state of Oklahoma for a six day period in August, 1994. The results were validated using ground observations from the 111 station Oklahoma Mesonet. Validation of the remote sensing algorithms with Mesonet observations produced comparable results to previous validation studies. In addition, the validation process revealed inadequacies in thermal modeling that had not been detected in previous validation studies leading to the development of a new approach to estimate atmospheric water vapor.     

厚度对月壤微波辐射亮温的影响

基于嫦娥系列卫星微波辐射计数据的月壤厚度反演是中国月球科学研究的重要目标之一。基于辐射传输方程,数值模拟了不同频率、（FeO+TiO₂）含量和表面温度条件下厚度对月壤微波辐射亮温的影响;基于嫦娥二号卫星微波辐射计（Chang’E Lunar Microwave Sounder,CELMS）数据,结合Apollo 计划获取的月壤厚度资料及其他月壤厚度资料,系统分析了厚度对CELMS观测数据的影响。结果表明：频率、（FeO+TiO₂）含量、表面温度对亮温的影响远大于厚度对亮温的影响,是基于CELMS数据进行月壤厚度反演的重要影响因素;低频、低（FeO+TiO₂）含量、低温条件下,厚度对CELMS数据的影响最大;利用3 GHz、凌晨时刻的CELMS数据进行月陆地区月壤厚度反演可行。研究结果对基于嫦娥系列卫星CELMS数据的月壤厚度反演具有重要参考意义。     

El Niño southern oscillation influences represented in ERS scatterometer-derived soil moisture data

Over the past decade, soil moisture products derived from microwave remote sensing data have gained increasing attention for the monitoring of agricultural, hydrological and climate processes. ERS-1 and ERS-2 scatterometer-derived time series of data available since 1992 enable the user to analyze the change of soil moisture patterns over time and to monitor events deviating from the normal. In this paper, ERS scatterometer-derived soil moisture products are compared with known occurrences of heavy rain and drought related to the strong El Niño (EN) event of 1997/1998. We investigated globally if the typical EN-related short term climate changes can be depicted in soil moisture data. EN consequences and their manifestation in the data are presented for the Americas, Africa and Asia. Furthermore, the weather situation during the EN event in China is compared to the scatterometer-derived soil moisture data set in more detail. It could be observed that most EN-related climate variations on the different continents are clearly reflected by remote sensing soil moisture data. Heavy rain and drought conditions reported in daily media, science papers, and forecasts by the NOAA Climate Prediction Center can be observed in anomaly data sets showing the deviation of soil moisture from the average. This also applies for the strong EN-related flood, which hit China in 1998 and following La Niña-related droughts. These analyses thus serve to demonstrate that information relevant to climatology is contained in the satellite scatterometer-derived soil moisture product, as well as in anomaly time series, derived from the existing soil moisture time series. Our procedure thus consisted of soil moisture time series calculation, soil moisture anomaly calculation, creation of time series and anomaly maps and the comparison of anomalies with meteorological data on three continents for the time period of outstanding El Nino years. The soil moisture data of TU Wien is available via the internet free of charge.     

面向土地资源管理的我国后续资源卫星谱段设置方法研究

谱段设置是资源卫星传感器设计的关键技术之一。该文针对土地资源管理对资源卫星光谱分辨率的需求。详细分析了收集和采集的主要土地利用/覆被光谱数据的特征，从主要地物的光谱可分性出发，提出了满足土地资源管理需要的资源卫星传感器谱段设置方案，并利用机载成像光谱数据进行波段优选和在轨资源卫星数据的模拟验证，分类对比研究表明，该优化谱段模拟图像土地利用／覆被分类效果好于TM和CBERS-1影像。     

The Free Air Geoid for Australia

Summary The free air geoid, which is the co-geoid obtained by the use of free air anomalies in Stokes' integral, is computed for Australia from available gravity data. The set of anomalies used to represent the outer zones had been obtained previously using a combined solution from satellite data and terrestrial gravimetry. The solutions so obtained for the free air geoid are compared with the astrogeodetic determination of the geoid on the Australian Geodetic Datum by Fischer and Slutsky and the accuracy of the comparisons is estimated.     

联合GPS和SARAL卫星测高数据构建南极Dome A区域DEM

南极冰盖数字高程模型(digital elevation model,DEM)对南极环境变化和地形研究具有重要作用,利用GPS实测数据和卫星测高数据建立DEM是构建南极冰盖表面DEM的重要方法。考虑到实测GPS数据的精度较高,而卫星测高的空间分辨率占优,本文探讨综合利用这两种数据构建南极Dome A区域DEM。法国国家空间研究中心和印度空间研究组织共同研制的SARAL卫星是Envisat的后续卫星,搭载的Alti Ka雷达高度计首次采用了Ka波段,可以极大减小电离层的影响,提高测距精度和卫星数据的空间分辨率。本文首先利用中国南极第29次科学考察在Dome A区域的实测GPS数据对SARAL数据进行精度评定,然后利用实测GPS数据对SARAL测高数据进行高程修正,联合GPS数据获取得到了Dome A区域300 m分辨率的DEM。结果表明SARAL的高程精度为0.615 m,而联合GPS数据能改善DEM精度,提高到0.261 m。     

Satellite imagery activism: Sharpening the focus on tropical deforestation

Since the first land remote sensing satellite was launched in the early 1970s, government agencies, private companies and research institutions have used satellite imagery data for a growing range of civil and commercial applications focused on natural resource management and exploitation, and environmental monitoring. The global diffusion of remote sensing expertize, along with growing public access to satellite images, has created conditions for improving levels of global transparency. One aspect of this global transparency is the advent of new users of imagery data – or 'imagery activists'– including, among others, issue-oriented nongovernmental organizations (NGOs), media groups, multinational organizations and academic researchers who now are able to access satellite imagery in order to draw domestic and international attention to particular public policy concerns. This paper broadly surveys the contemporary phenomenon of satellite imagery activism and outlines the main challenges facing imagery activists, particularly in relation to deforestation and other forest monitoring issues.     

Sources for the assessment of British woodland change in the twentieth century

After a discussion of the problems of defining woodland for the purpose of survey, the paper goes on to consider the sources available to geographers and others for the study of woodland change in Britain, particularly within the 20th century. The main sources considered are Ordnance Survey maps, aerial photographs and satellite remote sensing, Forestry Commission censuses. Forestry Commission and private estate records, land utilization surveys and agricultural statistics.     

Spherical prism magnetic effects by Gauss–Legendre quadrature integration

Regional spherical coordinate observations of the Earth's crustal magnetic field components are becoming increasingly available from shipborne, airborne, and satellite surveys. In assessing the geological significance of these data, theoretical anomalous magnetic fields from geologic models in spherical coordinates need to be evaluated. This study explicitly develops the elegant Gauss–Legendre quadrature formulation for numerically modelling the complete magnetic effects (i.e. potential, vector and tensor gradient fields) of the spherical prism. We also use these results to demonstrate the magnetic effects for the crustal prism and to investigate the crustal magnetic effects at satellite altitudes for a large region of the Middle East centred on Iran.     

利用NOAA-AVHRR数据进行积雪监测与制图的方法研究

本文在总结分析国内外现有方法的基础上,并根据大量的实验研究,介绍了利用NOAA－AVHRR遥感数据进行积雪监测和流域雪盖制图的方法。文章侧重介绍了AVHRR数据在积雪制图应用中的数据处理方法。也较为详细地介绍了利用遥感数据和地形数据的复合进行积雪信息提取的方法。研究表明：在地形相对复杂的地区使用AVHRR数据进行积雪监测和制图,采用监督分类的方法可获得较为理想的分类结果。利用GIS的空间分析方法,实现遥感和地形数据的复合分是积雪遥感制图高效和实用的方法之一。     

长江口水域多光谱遥感水深反演模型研究

利用Landsat-7 ETM 遥感影像反射率和实测水深值之间的相关性可以探测水深。该文介绍单波段、双波段比值和多波段3种线性回归模型以及动量BP人工神经网络水深反演模型。选择长江口北港河道上段作为研究区,利用上述模型,分两种情况进行水深反演:一是以河道全部历史样本建模;二是将河道按自然水深划分为浅水区和深水区分别建模。结果表明:神经网络模型预测精度高于线性回归模型;水深分区后线性回归和神经网络模型预测误差均有所减小。     

Thermodynamical Gruneisen's function for pure iron at the Earth's core conditions

summary . Calculations of the thermodynamical Gruneisen's gamma as a function of temperature and volume for iron are presented. The ranges of the relevant pressures and temperatures extend to those corresponding to the Earth's core. The various crystal structures of iron and several kinds of inter-molecular potential functions are considered. It is found that it is not possible to describe the Gruneisen's gamma for iron with the accuracy needed for an assessment of the thermal state of the core mainly because the available experimental data do not allow a definite choice among the possible potential functions.