基于卫星辐射率资料的两种三维云反演方法对比研究

基于格点统计插值分析系统（Gridpoint Statistical Interpolation analysis system,简称GSI）,利用粒子滤波（Particle Filter,简称PF）方法对卫星红外辐射率资料进行了云覆盖、云高等三维云图产品的反演研究。选取了具有高时空分辨率的静止卫星GOES（Geostationary Operational Environmental Satellites）-Imager辐射率资料进行了云反演试验,初步评估了PF云反演方法的可行性及其与多元极小残差（Multivariate and Minimum Residual,简称MMR）云反演方法的异同。结果表明:两种方法反演得到的云覆盖和云顶气压与NASA基于CO₂切片法反演得到的GOES云产品一致性较高。PF和MMR方法反演产品的优点是云图信息是三维分布的,相对于NASA提供的GOES云产品能提供更全方位立体的云信息。MMR方法需要利用一维变分逐步拟合观测来反演三维云图产品;PF方法采用不同模式垂直层的云覆盖比例作为不同粒子来近似后验概率分布,计算效率大大提高。进一步提出了一种新的基于“扰动粒子”的粒子滤波云反演方法,结果表明:在滤波过程中采用足够多的粒子样本（样本数量约为250）可以改进后验概率密度函数的估计,有效地避免了粒子发散问题,改善了云反演的结果。     

Approaches to Semantic Similarity Measurement for Geo-Spatial Data: A Survey

Semantic similarity is central for the functioning of semantically enabled processing of geospatial data. It is used to measure the degree of potential semantic interoperability between data or different geographic information systems (GIS). Similarity is essential for dealing with vague data queries, vague concepts or natural language and is the basis for semantic information retrieval and integration. The choice of similarity measurement influences strongly the conceptual design and the functionality of a GIS. The goal of this article is to provide a survey presentation on theories of semantic similarity measurement and review how these approaches – originally developed as psychological models to explain human similarity judgment – can be used in geographic information science. According to their knowledge representation and notion of similarity we classify existing similarity measures in geometric, feature, network, alignment and transformational models. The article reviews each of these models and outlines its notion of similarity and metric properties. Afterwards, we evaluate the semantic similarity models with respect to the requirements for semantic similarity measurement between geospatial data. The article concludes by comparing the similarity measures and giving general advice how to choose an appropriate semantic similarity measure. Advantages and disadvantages point to their suitability for different tasks.     

基于AMSR-E数据的多年冰密集度反演算法研究

In recent years, the rapid decline of Arctic sea ice area(SIA) and sea ice extent(SIE), especially for the multiyear(MY) ice, has led to significant effect on climate change. The accurate retrieval of MY ice concentration retrieval is very important and challenging to understand the ongoing changes. Three MY ice concentration retrieval algorithms were systematically evaluated. A similar total ice concentration was yielded by these algorithms, while the retrieved MY sea ice concentrations differs from each other. The MY SIA derived from NASA TEAM algorithm is relatively stable. Other two algorithms created seasonal fluctuations of MY SIA, particularly in autumn and winter. In this paper, we proposed an ice concentration retrieval algorithm, which developed the NASA TEAM algorithm by adding to use AMSR-E 6.9 GHz brightness temperature data and sea ice concentration using 89.0GHz data. Comparison with the reference MY SIA from reference MY ice, indicates that the mean difference and root mean square(rms) difference of MY SIA derived from the algorithm of this study are 0.65×106 km2 and0.69×106 km2 during January to March, –0.06×106 km2 and 0.14×106 km2 during September to December respectively. Comparison with MY SIE obtained from weekly ice age data provided by University of Colorado show that, the mean difference and rms difference are 0.69×106 km2 and 0.84×106 km2, respectively. The developed algorithm proposed in this study has smaller difference compared with the reference MY ice and MY SIE from ice age data than the Wang's, Lomax' and NASA TEAM algorithms.     

基于神经网络技术的多因子遥感水深反演模型

采用动量BP人工神经网络方法,研究影响多光谱遥感水深反演的各种因素,概括出主要的影响因素,即:泥沙与叶绿素,通过在网络输入端加入泥沙参数因子与叶绿素参数因子,对神经网络进行训练,对大连湾的水深进行反演,取得较好的效果。     

地温敏感波段的遥感图像反演算法研究

针对应用于地表温度反演的航天遥感数据波段选择问题,文章提出了利用波长范围为8~10.5μm的热红外遥感数据反演地表温度的单通道反演算法:从温度敏感性的角度证明了利用波长范围为8~10.5μm的遥感数据反演地表温度的合理性;在此基础上,将仪器光谱响应率引入到基于大气校正原理的单通道反演算法中,提高了地表温度的反演精度。最后通过实验证明了利用此波段的热红外遥感数据反演地表温度的可行性。     

晴空时大气红外遥感及其反演问题研究 II. 反演试验研究

前文给出了卫星红外观测资料的反演处理方法，并对方法作了理论上的分析，在本文中，我们将此方法应用到TOVS、GOES-8实际资料及AIRS模拟观测资料处理中并重点对TOVS资料进行试验。在反演中，我们将大气温度廓线和水汽混合比（lnq）廓线用各自的经验正交函数（EOF）表示以提高反演的稳定性并缩短计算时间，同时采用一种过滤操作以加速迭代的收敛速度。除了用本文提出的方法对TOVS资料进行处理外，还用国际TOVS处理软件包（ITPP-4.0）对同样的资料进行反演。试验表明，本文方法的反演结果优于ITPP的结果。AIRS模拟反演结果表明，高分辨率红外垂直探测器的遥感精度能够达到温度1 K、水汽10%。     

卷积神经网络多层特征联合的遥感图像检索

针对卷积神经网络的特征表达方法难以满足大规模遥感图像检索需要的问题,该文将卷积层特征和全连接层特征进行联合,提出一种基于卷积神经网络多层特征联合的遥感图像检索方法。该方法提取不同卷积层特征作为图像的局部特征,提取全连接层特征作为感兴趣区域,并对二者进行跨层整合得到新的图像特征并应用于图像检索。实验结果表明,与利用单一的全连接层或者卷积层特征以及传统的经典检索方法相比,该方法取得了很好的检索结果,能够更好地保留图像的全局信息和空间结构信息,提高遥感图像检索的性能。     

RETRIEVING OVER-OCEAN PRECIPITABLE WATER FROM THE SSM/I MEASUREMENTS WITH SEVERAL REGRESSION ALGORITHMS

A collocated SSM/I and radiosonde measurement data set provided by the NASDA(Japan)was used to retrieve the total precipitable water(PW)over oceans.The retrieval results obtainedwith several regression algorithms were compared against the radiosonde measurements.It isshown that:(a)the routinely operational algorithm of Alishouse et al.(1990)yields significantunderestimation in high PW regime and overestimation in low PW regime;(b)a cubic correctionby Colton and Poe(1994)is not sufficient and globally improves slightly the retrieval results;and(c)the regression algorithm with the form of brightness temperature(T_b)function In (280-T_b)gives a little largely scattered retrievals in whole PW range but without considerable over-andunderestimates in low and high PW regimes.To improve the estimation of the oceanic precipitablewater from the SSM/I measurements,a composite algorithm with different forms of T_b function inlow.medium and high PW regimes is proposed and tested.     

Are opinions expressed in land-use planning documents?

A great deal of research on information extraction from textual datasets has been performed in specific data contexts, such as movie reviews, commercial product evaluations, campaign speeches, etc. In this paper, we raise the question on how appropriate these methods are for documents related to land-use planning. The kind of information sought concerns the stakeholders, sentiments, geographic information, and everything else related to the territory. However, it is extremely challenging to link sentiments to the three dimensions that constitute geographic information (location, time, and theme). After highlighting the limitations of existing proposals and discussing issues related to textual data, we present a method called OPILAND (OPinion mIning from LAND-use planning documents) designed to semi-automatically mine opinions related to named-entities in specialized contexts. Experiments are conducted on a Thau lagoon dataset (France), and then applied on three datasets that are related to different areas in order to highlight the relevance and the broader applications of our proposal.     

强热带风暴碧利斯(0604)引发的特大暴雨中尺度结构多普勒雷达资料分析

强热带风暴 “碧利斯” (Bilis) 于2006年7月14日12:50在福建省霞浦县北壁镇再次登陆, 与南海季风相互作用, 在福建省引发特大暴雨。作者利用双多普勒雷达三维风场反演技术对厦门和龙岩新一代多普勒雷达时间同步探测资料进行了风场反演, 综合利用雷达回波强度资料, 对造成长泰、 漳州特大暴雨的中尺度对流系统的三维结构及其演变特征进行了详细分析。结果表明: (1) 此次特大暴雨主要是由中低层西南[CD*2]东北走向的β中尺度辐合线引发的, 辐合线对于水汽输送以及暴雨的形成、 触发、 维持具有重要作用, 辐合线在暴雨的整个生命史过程中经历了由弱变强、 由强变弱的演变过程, 变化过程与降水的强弱演变过程基本同步。 (2) 由于丰富的水汽供应和中低层辐合线的动力抬升作用, 西南[CD*2]东北走向的β中尺度回波带的西南不断有新的γ中尺度对流单体生成, 在沿着辐合线向东北移动过程中进一步发展、 合并形成β中尺度对流线, 造成持续的强降水。最后, 还给出了此次特大暴雨的三维云系结构模型。