TM图像在新疆奇台北山煤田火区动态监测中的应用

本文以实测的煤田火区地物波谱数据为依据,对用于煤田火区各地物解译的遥感信息源──TM图像的最佳时相选择、最佳波段组合和煤田火区地物在TM图像上的影像特征进行了探讨。采用多时相TM图像对新疆奇台北山煤田火区进行动态监测及火情预测的成果进行了叙述,该勘查研究成果对指导该煤田火区灭火工程设计及后期防火管理有较大实用价值。对其它煤田火区火情监测也有一定借鉴作用。     

Modelling radiation quantities and photolysis frequencies in the troposphere

STAR (System for Transfer of Atmospheric Radiation) was developed to calculate accurately and efficiently the irradiance, the actinic flux, and the radiance in the troposphere. Additionally a very efficient calculation scheme to computer photolysis frequencies for 21 different gases was evolved. STAR includes representative data bases for atmospheric constituents, especially aerosol particles. With this model package a sensitivity study of the influence of different parameter on photolysis frequencies in particular of O₃ to Singlet D oxygen atoms, of NO₂, and of HCHO was performed. The results show the quantitative effects of the influence of the solar zenith angle, the ozone concentration and vertical profile, the aerosol particles, the surface albedo, the temperature, the pressure, the concentration of NO₂, and different types of clouds on the photolysis frequencies.Notation I _A(, ) actinic flux - I _H(, ) irradiance - L(, , , ) radiance - wavelength - azimuth angle - cosine of zenith angle - _s cosine of solar zenith angle - optical depth - _s scattering coefficient - _c extinction coefficient - _o single scattering albedo - p _mix mixed phase function - g _mix mixed asymmetry factor - J _gas photolysis frequency     

卫星海洋水色遥感的辐射模式研究

海洋水体向上的辐射由水中多种成分的浓度所决定，同时辐射的强度十分微弱并随着时间和空间在变化。因此，海洋水色遥感需要从水体和大气辐射传递机理出发，研究到达卫星遥感器的辐射模式，以达到模拟仿真卫星水色遥感图像和卫星图像质量预测的目的。本研究通过叶绿素、悬浮泥沙和黄色物质等海洋水色的主要因子，分别从可见光波段和荧光波段对辐射的贡献出发，发展了海洋水体离水辐射率模式。在卫星水色遥感机理的基础上，同时运用Iqbal，Gordon和Sturm等的大气程辐射模式和太阳耀光模式，使卫星海洋水色遥感的辐射模式系统化，模拟仿真了我国1990年9月3日发射的FYIB卫星两个海洋水色通道的全轨道辐射图像，同时利用从德国柏林大学气象中心接收到的1990年9月23－25日卫星图像进行验证。结果认为，本文所发展的模式可应用于卫星图像质量的预测和水色信息的提取。     

一次新的厄尔尼诺事件即将形成

一次新的厄尔尼诺事件即将形成宋家喜（国家海洋环境预报中心，北京）在１９９１～１９９５年的五年中，赤道东太平洋共发生了三大厄尔尼诺事件，即１９９１年５月至１９９２年６月，１９９３年３月至１０月，１９９４年１０月至１９９５年２月。也有人认为是一次长厄尔尼...     

A study on quality and availability of COCTS images of HY-1 satellite by simulation

ＩＮＴＲＯＤＵＣＴＩＯＮＨＹ - 1ｓａｔｅｌｌｉｔｅｗｉｌｌｂｅｌａｕｎｃｈｅｄｔｏａｎａｌｔｉｔｕｄｅｏｆ 870ｋｍｔｏｇｅｔｈｅｒｗｉｔｈｍｅｔｅｏｒｏｌｏｇｙｓａｔｅｌ ｌｉｔｅＦＹ - 1 .Ｉｎｏｒｄｅｒｔｏｇｅｔａｓｈｏｒｔｒｅｐｅａｔｐｅｒｉｏｄ ,ｏｒｂｉｔｔｒａｎｓｆｅｒｗｉｌｌｂｅｍａｄｅａｎｄｆｉｎａｌｌｙｔｈｅｓａｔｅｌｌｉｔｅｗｉｌｌｍｏｖｅａｎｄｏｐｅｒａｔｅｉｎａｎｅａｒｓｕｎ ｓｙｎｃｈｒｏｎｏｕｓａｎｄｎｅａｒ ｐｏｌａｒｏｒｂｉｔａｔａｎａｌｔｉｔｕｄｅｏｆ798ｋｍ .Ｔｈｅｉ…     

Assimilation of the FY-4A AGRI Clear-Sky Radiance Data in a Regional Numerical Model and Its Impact on the Forecast of the “21·7” Henan Extremely Persistent Heavy Rainfall

Assimilation of the Advanced Geostationary Radiance Imager(AGRI) clear-sky radiance in a regional model is performed. The forecasting effectiveness of the assimilation of two water vapor(WV) channels with conventional observations for the “21·7” Henan extremely heavy rainfall is analyzed and compared with a baseline test that assimilates only conventional observations in this study. The results show that the 24-h cumulative precipitation forecast by the assimilation experiment with the addition ...     

Thunderstorm and Lightning Activities over Western Pacific, Northern Indian Ocean and South China Sea Along with Their Adjacent Lands

The Lightning Imaging Sensor (LIS) and Radar Precipitation Feature (RPF) data are used to investigate the activities and properties of lightning and thunderstorms over a region including the Western Pacific, northern Indian Ocean and the South China Sea along with their adjacent lands. The lands feature significantly more frequent lightning flashes and thunderstorms than the oceans, especially the open oceans. The highest densities of lightning and thunderstorm occur over the Strait of Malacca and the southern foothills of the Himalayas. Over the ocean regions, the Bay of Bengal and the South China Sea are characterized by relatively frequent lightning and thunderstorm activities. Larger average spatiotemporal size and optical radiance of flashes can be found over the oceans; specifically, the offshore area features the most significant flash duration, and the open ocean area is characterized by the greatest flash length and optical radiance. The smallest average values of flash properties can be found over and around the Tibetan Plateau (TP). The oceanic thunderstorms tend to have a significantly larger horizontal extent than the continental thunderstorms, with the former and latter having the average area of the regions with radar reflectivity larger than 20 dBZ, generally over 7000 km2 and commonly below 6000 km2 , respectively. The TP thunderstorms show the smallest horizontal extent. Meanwhile, the oceanic thunderstorms exhibit greater 20 dBZ but smaller 40 dBZ top heights than the continental thunderstorms. The average flash frequency and density of the oceanic thunderstorms are typically less than 5 fl min–1 and 0.3 fl 100 km–2 min–1, respectively; in contrast, the corresponding values of continental thunderstorms are greater. It is explored that the regions associated with strong convective thunderstorms are more likely to feature small-horizontal-extent and low-radiance flashes.     

Improved Land Use and Leaf Area Index Enhances WRF-3DVAR Satellite Radiance Assimilation: A Case Study Focusing on Rainfall Simulation in the Shule River Basin during July 2013

The application of satellite radiance assimilation can improve the simulation of precipitation by numerical weather prediction models. However, substantial quantities of satellite data, especially those derived from low-level(surface-sensitive)channels, are rejected for use because of the difficulty in realistically modeling land surface emissivity and energy budgets.Here, we used an improved land use and leaf area index(LAI) dataset in the WRF-3 DVAR assimilation system to explore the benefit of using improved quality of land surface information to improve rainfall simulation for the Shule River Basin in the northeastern Tibetan Plateau as a case study. The results for July 2013 show that, for low-level channels(e.g., channel 3),the underestimation of brightness temperature in the original simulation was largely removed by more realistic land surface information. In addition, more satellite data could be utilized in the assimilation because the realistic land use and LAI data allowed more satellite radiance data to pass the deviation test and get used by the assimilation, which resulted in improved initial driving fields and better simulation in terms of temperature, relative humidity, vertical convection, and cumulative precipitation.     

基于月球反射的遥感器定标跟踪监测

月亮辐照度是可见近红外波段一种稳定的辐射参考基准,对月观测已成为星载遥感仪器辐射定标和验证的一种新方法。风云三号03星(FY-3C)中分辨率光谱成像仪(Moderate Resolution Spectral Imager,MERSI)增加了对月观测功能,改进了太阳反射波段的在轨辐射定标。本文收集分析了MERSI在轨工作以来的全部11组对月观测数据,利用通道间辐照度比值方法移除月相角,日—月—星相对距离等因素对月亮辐照度观测值的影响,开展了可见光近红外波段的辐射定标工作,实现了MERSI太阳反射通道的辐射定标系数动态跟踪和评估。通过线性回归及统计发现,通道8辐射响应的年衰减率达到了14.55%,通道9达到了8.42%,通道1、6、10、11、16和19的年衰减率为1.15%—4.72%,其余通道未检测到衰减。研究结果可以用于订正MERSI数据的辐射定标系统性偏差,提高MERSI全寿命期的辐射定标精度。     

考虑植被覆盖因子的地形辐射校正模型

针对传统的地形辐射校正模型无法适用复杂地表覆盖类型而导致的校正精度较低的问题,该文提出了一种考虑像元植被覆盖因子的模型。山区遥感影像像元大部分为植被与岩石、裸土的混合像元,针对混合像元中岩石、裸土部分应用太阳-地表-传感器模型,而对于植被覆盖区则采用考虑植被垂直生长特性的太阳-树冠-传感器模型,两模型用像元植被覆盖因子拟合为新的太阳-植被覆盖因子-传感器模型。利用覆盖江西实验区的Landsat-8陆地成像仪影像和数字高程模型数据进行了校正比对分析,结果表明该方法可有效地消除地形起伏对辐射亮度的影响。