岩石的热惯量研究

本文阐述了热惯量的物理意义及其在地质遥感中的作用。在测得２３种岩石热物理性质的有关参数──热传导率、热容量和密度的基础上，计算并列表给出了岩石的热惯量值和热扩散系数等基础数据。文中分析讨论了沉积岩、变质岩和岩浆岩岩石的热惯量变化由高到低的初步规律。取得了碳酸盐岩和砂岩类等沉积岩和沉积浅变质岩的热惯量差异的结果，指出了它们的易区分性；也指出了中－酸性、碱性岩浆岩之间的热惯量值差异较小，不易区分。     

红外热象仪在岩石力学遥感基础实验中的应用

在岩石力学性质实验中，使用ＡＧＡ红外热象仪观测到随岩石应力的增加，岩石表面红外辐射温度升高；由岩石破裂处观测到岩石内部增温一般在２—４℃。也观测到随应力变化，岩石红外辐射温度场的变化过程，即随岩石应力增加，在弹性形变期其表面红外辐射温度呈上升趋势，在塑性形变期呈下降趋势，之后岩石破裂。这是很有重要意义的一种物理现象。热象仪的观测结果为红外遥感观测地应力变化提供了理论依据。     

从空间测量陆面温度的可行性

为了将用于从卫星热红外数据测量海面温度的多波段方法应用到陆面温度的测量,我们通过大气辐射输运模型的模拟计算进行了可行性研究。所模拟的大气条件和表面温度的变化范围宽得足于覆盖晴天大气性质和表面温度的实际变化,这些变化对陆地来说比对海洋的大。地面高程也作为最重要的地形影响包括在模拟计算中。用频谱发射率的测量值或计算值表征的地面覆盖,包括雪、粘土、沙地和树叶的样品。从统计分析得到的经验反演模型在无云条件下可由卫星三个红外波段测量,较精确地估算陆面温度,在0—40°观察角范围内,其标准偏差小于0.3 K,最大误差小于1K。热红外波段可以是气象卫星甚高分辨率辐射计(AVHRR),也可以是正被EOSAT和NASA考虑用于将来遥感测量的传遥器,即陆地卫星上增加的热红外多波段或为陆面/海面测量设计的宽视野传遥器(Sea WiFS)。     

基于MODIS数据的干旱区土壤水分反演

为了更好地研究内蒙古额济纳盆地的土壤水分时空分布及动态变化,基于MODIS数据,利用热惯量模型,计算了表观热惯量,并与实测数据进行回归分析建模,反演了内蒙古额济纳盆地的土壤水分。结果表明,利用MODIS数据产品,反演参量获取简单,可降低反演土壤含水量的复杂性,有利于大、中尺度的实际应用;砂土对应的表观热惯量均值较大,粘土次之,壤土最小;相比粘土,壤土和砂土的表观热惯量值比较大且分散;绿洲区表观热惯量值比戈壁和沙漠区大;热惯量模型在20 cm左右深度土壤水分反演效果最好,可有效反演干旱区土壤水分。     

从宽波段热红外图像反演组分温度的相关问题讨论——通道响应函数和比辐射率波段变化的影响

对于宽波段传感器,不一定能直接由普朗克定律或者斯蒂芬玻尔兹曼定律建立温度与辐射亮度的关系。在知道传感器通道响应函数和像元组分比辐射率波段变化的情况下,只要恰当地拟合出黑体温度和其宽波段热辐射的对应经验关系式,并计算一个通道响应函数加权平均的比辐射率,则从混合像元的宽波段多角度热红外观测仍可较准确地反演组分温度。以AMTIS为例,文中给出了两种拟合宽波段传感器亮度温度和辐射亮度之间关系的方式:一种是从斯蒂芬玻尔兹曼定律的形式出发的;另一种则是用普朗克定律,选择一个合适的波长,使得AMTIS传感器随温度变化的热辐射曲线和普朗克函数在某个波长处的热辐射曲线两者之间尽可能地平行。文中以两个例子说明了这两种方式在宽波段传感器组分温度反演中的应用和误差,分析了比辐射率波段变化对组分温度反演的影响。     

热惯量法在监测土壤表层水分变化中的研究

利用遥感方法监测一定层水深土壤水分变化，关键是建立卫星数据与地表水热变化关系，该文地遥感定量反演土壤水热变化的数值模拟系统及热惯量在其边界，初始条件确定中所起的作用进行的简述，并介绍了热惯量法求解表层水分含量的发展概况，为进一步提高定量化监测方法的地必琢计算精度，该文发展了地表能量平均方程的一种新的化简方法，经过这样的处理，可从遥感图象数据直接得到真实热惯量值，进而得到土壤水分含量分布，通过野外实     

条件植被温度指数及其在干旱监测中的应用

应用NOAA－AVHRR数据，在用条件植被指数、条件温度指数和距平植被指数进行年度间相对干旱程度监测的基础上，提出了条件植被温度指数的概念，它适用于监测某一特定年内某一时期（如旬）区域级的相对干旱程度。条件植被温度指数的定义既考虑了区域内归一化植被指数的变化，又考虑了在归一化植被指数值相同条件下土地表面温度的变化。陕西省关中平原地区2000年3月下旬干旱的监测结果表明，条件植被温度指数能较好地监测该区域的相对干旱程度，并可用于研究干旱程度的空间变化特征，对干旱的监测结果与用土壤热惯量模型反演的土壤表层含水量的结果基本吻合。     

基于改进热惯量模型的表层土壤水反演研究

针对改进热惯量模型需要通过对地面实测的温度进行插值推算地表最高温度,而玛多县属高原地区,较难获取实测数据,利用MODIS地表温度产品的4个瞬时值计算日平均地表温度,结合修正普适性单通道算法反演HJ-1B地表温度,推算出地表最高温度,从而减少了改进热惯量模型对地面观测数据的依赖,进而利用HJ-1B数据反演了玛多县土壤水。结果表明:本文方法可行,能够获得较高分辨率的土壤水空间分布结果,拓宽了HJ-1B数据的应用范围。     

HJ-1B热红外辐射定标对地表温度反演的影响

辐射定标是地表温度反演的关键环节。在实际应用中,定标参数的选取直接影响辐射定标结果。由于卫星在轨定标系统的灵敏度会随时间发生改变,这使得实际的辐射定标存在不确定性。本文基于单波段热红外辐射传输方程给出了辐射定标影响地表温度反演的敏感性分析模型,并重点对HJ-1B热红外波段的辐射定标问题及其对地表温度反演的影响进行讨论和分析。敏感性分析模型显示,在一般的情形下,辐射定标偏差与地表温度反演误差的比值在数值上约为1∶11,即0.1个单位(W·m–2·sr–1·μm–1)的辐射定标偏差可能引起1.1 K左右的温度反演误差。由于对HJ-1B热红外波段定标参数的更新存在滞后,即使仅考虑相邻年份间的定标偏差,相应的地表温度平均绝对误差也在1.0—2.0 K左右。在更严重的情形下,因辐射定标偏差引起的地表温度误差甚至高达5.0 K以上。同时,分析结果也表明对HJ-1B的存档影像,无论使用其头文件中的定标参数还是当年公布的定标参数,定标后辐射亮度值的偏差均存在一定的不稳定性。针对当前在HJ-1B定标参数更新方面的不足,本文假定传感器辐射性能变化是匀速稳定的,相应地提出了线性内插修正法和线性外推法两个定标参数估计/修正方案。通过线性内插的方法进行辐射定标修正后,在一定程度上减小了误差的不稳定性,与MODIS B31波段的亮温相比,偏差在1.0 K以内(约为0.5 K)。当定标参数尚未公布时,由线性外推法修正后的辐射定标结果所得亮温的偏差约为1.0 K。与在大亚湾核电站附近海域进行的一次卫星同步观测(2011年12月18日)相比,经两个方案修正后的海表温度偏差分别约为0.2 K和0.7 K。案例分析的结果表明,在现阶段,线性内插修正法和线性外推法是简单有效的,可供用户在实际应用中参考和使用。     

应用LSF概念模型反演草冠层叶面温度的试验

试验在已知土壤表面温度的前提下，分别利用AVHRR卫星遥感资料和准同步地面观测数据，应用LSF概念模型成功反演了草冠层叶面温度。通过对星、地资料反演的草冠层叶面温度比较发现，二者反演结果相差小于0．2K，说明利用卫星遥感资料，应用LSF概念模型反演草场冠层叶面温度可获得比较满意的结果。假设其他参数不变，分别对不同叶面发射率和不同土壤表面发射率反演的叶面温度分析发现，组分发射率的估算精度对反演结果影响较小，而整层空气柱可降水量的估算精度对卫星资料反演草冠层叶面温度影响大，用探空资料和露点温度估算的整层空气柱可降水量可导致反演的叶面温度相差达1．1K。在水分供应充足条件下，晴天11：00-17：00时，即使太阳总辐射强，叶面温度的变化幅度比土壤表面温度、空气温度小。以1999年8月6日为例，叶面温度变化仅有1．22K，而同时土壤表面温度变化为9．5K，1．5m高的空气温度变化为6．0K，叶面温度变化幅度比土壤表面温度、空气温度平缓。试验结果还表明，采用Becker和李召良的分裂窗模型反演青藏高原东南缘地区的陆地表面温度效果较好。     

Separating near surface thermal inertia signals from a thermal time series by standardized principal component analysis

Principal component analysis has been applied to remote sensing data to identify spatiotemporal patterns in a time series of images. Thermal inertia is a surface property that relates well to shallow surface thermal and physical properties. Mapping thermal inertia requires quantifying surface energy balance components and soil heat flux, both of which are difficult to measure remotely. This article describes a method to map soil thermal inertia using principal component analysis applied to a time series of thermal infrared images and it also assesses how sensitive this method is to the time intervals between images. Standardized principal component analysis (SPCA) was applied to thermal infrared images captured at half-hour intervals during a complete diurnal cycle. Shallow surface thermal properties accounted for 45%, 82% and 66% of the spatiotemporal variation in surface temperature observed during the heating phase, cooling phase and over the total diurnal cycle respectively. The remaining 55%, 18% and 34% of the variation was attributed to transient effects such as shadows, surface roughness and background noise. Signals related to thermal inertia explained 18% of total variation observed in a complete diurnal cycle and 7% of variation in the cooling series. The SPCA method was found useful to separate critical information such as timing and amplitude of maximum surface temperature variation from delays related to differential heating induced by micro-topography. For the field conditions experienced in this study, decreased temporal resolution when sampling intervals were greater than an hour significantly reduced the quality of results.     

Generation of thermal inertia image over a part of Gujarat: A new tool for geological mapping

Thermal inertia is a volume property and can be used to detect the subsurface features in an alluvium-covered area. A thermal inertia image has been generated over a part of Gujarat using consecutive day and night NOAA-AVHRR data. Gujarat contains two important rift basins in the western margin of India, namely, Cambay and Kutch basins. Major land covers exist in this region are alluvium, continental sediments, various rocks of Mesozoic and Cenozoic origin followed by Deccan Volcanics, tertiary and quaternary deposits. Validation of thermal inertia parameters with existing values obtained from literature indicates the efficacy of the developed technique. The study indicates that thermal inertia image can be used as a new method for geologic mapping/basin delineation where exposure is less or contrast is negligible between litho-units using traditional photography/sensing techniques.     

2002年秋季山东省干旱遥感监测分析

利用极轨气象卫星遥感资料对2002年山东省秋季干旱进行监测和服务,其监测方法主要采用热惯量法。为了提高土壤水分模式的计算精度,将全省分为4个区域,对利用卫星资料反演的地表温度日较差进行植被指数等环境因素订正。在地理信息系统支持下,比较准确地计算出农田受旱面积,效果良好。     

Advances in understanding of the mechanism for generation of earthquake thermal precursors detected by satellites

Stresses building up during an earthquake preparation phase also manifest themselves in the form of a so called increased land surface temperature (LST) leading to a thermal precursor prior to the earthquake event. This phenomenon has now been validated by our observations of short-term thermal anomalies detected by infrared satellite sensors for several recent past earthquakes around the world. The rise in infrared radiance temperature was seen to vary between 5 and 12 °C for different earthquakes. We discuss in this paper different explanations for the generation of such anomalies that have been offered. Emission of gases due to the opening and closure of micropores upon induced stresses and also the participation of ground water have been propounded as a possible cause for generation of thermal anomalies. Seismo-ionosphere coupling, by which gases like radon move to the earth–atmosphere interface and cause air ionization thus bringing about a change in air temperature, relative humidity, etc., has been put forth by some workers. A mechanism of low frequency electromagnetic emission was tested and experimented by scientists with rock masses in stressed conditions as those that exist at tectonic locations. The workers proposed the positive hole pair theory, which received support from several scientific groups. Positive holes (sites of electron deficiency) are activated in stressed rocks from pre-existing yet dormant positive hole pairs (PHPs) and their recombination at rock–air interface leads to a LST rise. A combination of remote sensing detection of rock mechanics behavior with a perception of chemistry and geophysics has been applied to propose the remote sensing rock mechanics theory. Remote sensing detections of such anomalies confirm so far proposed lab theories for such a hotly debated field as earthquake precursor study by providing unbiased observations with consistency in time and space distribution.     

Seasonal sea level change from TOPEX/Poseidon observation and thermal contribution

Seasonal steric sea-level change due to temperature variation in the mixing layer is assessed using space-measured sea-surface temperature data and historical in situ temperature measurements. The results are compared with TOPEX/Poseidon satellite altimeter measurement at different large spatial scales. It is indicated that thermal effect accounts for much of the observed seasonal variability, especially when averaging over zonal regions. Some regional seasonal patterns of sea-level anomalies in the tropical oceans are well represented by the thermal model prediction. Systematic differences are shown between TOPEX/Poseidon observation and thermal contribution at a 1–2 cm level. The potential causes for these differences are discussed, including water mass exchanges among the atmosphere, land, and oceans, and error sources in the steric result and geophysical corrections applied in TOPEX/Poseidon data. Received: 25 September 1998 / Accepted: 13 July 1999     

青藏高原雅江缝合带及班公湖-怒江缝合带热红外遥感研究

对青藏高原进行了热红外遥感研究,发现热异常区域变化与前人结论不符.过去认为青藏高原南部的雅江缝合带温度高,北部低;而本文的研究结果是中部的班公-怒江缝合带地区高,雅江缝合带次之,藏北最低.将青藏高原雅江和班公怒江缝合带地区作为研究示范区,开展青藏高原陆面温度场、计算地表比辐射率和野外地表层钻孔测温与数据处理等研究,探索热红外遥感与构造热动力学关系的机理,为青藏高原新构造运动和深部热动力学研究提供科学依据,取得了青藏高原热动力学研究的新成果.     

基于MODIS数据对不同植被覆盖下土壤水分监测的可行性研究

论文利用2005年、2006年怀来实验场附近玉米生长期中的多次野外试验数据，以热惯量模型为基础，探讨MODIS数据监测土壤水分的可行性。论文对该模型与算法进行了分析，并探讨了不同植被覆盖度下，热惯量方法监测土壤水分的可行性。论文引入归一化植被指数对热惯量法进行修正，得到一个新的回归参数，通过实验分析验证，在不同植被覆盖下，该参数与土壤含水量具有较好的相关关系，具有一定的实际可行性。