Assimilation of ASAR data with a hydrologic and semi-empirical backscattering coupled model to estimate soil moisture

The most promising approach for studying soil moisture is the assimilation of observation data and computational modeling.However,there is much uncertainty in the assimilation process,which affects the assimilation results.This research developed a one-dimensional soil moisture assimilation scheme based on the Ensemble Kalman Filter(EnKF)and Genetic Algorithm(GA).A two-dimensional hydrologic model-Distributed Hydrology-Soil-Vegetation Model(DHSVM)was coupled with a semi-empirical backscattering model(Oh).The Advanced Synthetic Apertture Radar(ASAR)data were assimilated with this coupled model and the field observation data were used to validate this scheme in the soil moisture assimilation experiment.In order to improve the assimilation results,a cost function was set up based on the distance between the simulated backscattering coefficient from the coupled model and the observed backscattering coefficient from ASAR.The EnKF and GA were used to re-initialize and re-parameterize the simulation process,respectively.The assimilation results were compared with the free-run simulations from hydrologic model and the field observation data.The results obtained indicate that this assimilation scheme is practical and it can improve the accuracy of soil moisture estimation significantly.     

从科普插图看托勒密的地心说

古希腊著名天文学家托勒密一生著作很多,他和他的学说在天文学发展中无疑占有重要地位,其中最为著名、影响甚广的,似乎是被诬蔑为"臭名昭著"的"地心说"。不过,在中国的天文学科普书籍中,作者注意到有两种不同版本的"地心说"插图,两者反映的科学含义有很大差别。试图从这两种不同版本的插图来探讨"地心说"为什么能够统治那么多年。     

洛阳分县温度周滚动预报系统

利用洛阳9县(市)2002年11月~2004年9月逐日最高、最低气温资料,应用欧洲中心数值预报产品,建立了洛阳9个县(市)的温度周滚动预报方程。2004~2005年试报结果表明:24~48 h预报准确率在70%左右,绝对误差在2℃以内;24~144 h预报准确率在62%~70%之间,绝对误差在2℃左右;最低气温预报效果要好于最高气温,最低气温的绝对误差与准确率分别为1.98℃和67%,最高气温的绝对误差与准确率分别为2.28℃和61%。     

珠江口二类水体水色三要素的优化反演

根据2003年1月份珠江口实测资料获得了适合该海域的相关参数,建立了适用于该海域的二类水体水色三要素优化反演模型,同步优化反演得到了与2003年1月25～26日实测站点相对应的2003年1月29日的SeaWiFs图像像元点的水色三要素,反演与实测水色三要素的平均相对误差分别为：叶绿素14．9％,悬浮泥沙12．1％,黄色物质13．6％。研究结果说明本研究建立的优化反演模型比较适用于珠江口二类水体水色三要素的反演,且具有较高的反演精度。     

黄海绿潮应急溯源数值模拟初步研究

基于三维全动力POM 海洋模式, 根据2008 年6 月1 日海监飞机监测绿潮所在位置, 采用拉格朗日粒子追踪法反向积分, 追溯绿潮来源。数值模拟结果显示, 回溯至5 月中旬, 绿潮主要来源于黄海南部江苏连云港和盐城近海海域。黄海绿潮溯源数值模拟, 为政府相关部门了解绿潮的源头, 并采取相应的措施提供依据, 进而为保护生态环境、防灾减灾做贡献。     

Strain localization due to structural in-homogeneities in the Central European Basin System

The large-scale crustal deformations observed in the Central European Basin System (CEBS) are the result of the interplay between several controlling factors, among which lateral rheological heterogeneities play a key role. We present a finite-element integral thin sheet model of stress and strain distribution within the CEBS. Unlike many previous models, this study is based on thermo-mechanical data to quantify the impact of lateral contrasts on the tectonic deformation. Elasto-plastic material behaviour is used for both the mantle and the crust, and the effects of the sedimentary fill are also investigated. The consistency of model results is ensured through comparisons with observed data. The results resemble the present-day dynamics and kinematics when: (1) a weak granite-like lower crust below the Elbe Fault System is modelled in contrast to a stronger lower crust in the area extending north of the Elbe Line throughout the Baltic region; and (2) a transition domain in the upper mantle is considered between the shallow mantle of the Variscan domain and the deep mantle beneath the East European Craton (EEC), extending from the Elbe Line in the south till the Tornquist Zone. The strain localizations observed along these structural contrasts strongly enhance the dominant role played by large structural domains in stiffening the propagation of tectonic deformation and in controlling the basin formation and the evolution in the CEBS.     

造山带岩石圈化学结构平面图的编制——以秦岭—大别造山带为例

国内外岩石圈化学组成的编图研究还处于探索阶段。笔者从岩石圈化学结构的思路出发 ,提出了编图的 3个地球化学指标 (铅同位素组成、T2DM 和同位素年代学 )和表示方法。以秦岭—大别造山带为例 ,同位素组成图可以反映构造分区和地壳生长历史 ,对造山过程和深部壳幔相互作用也有明确的显示 ;结合地质年代学的资料 ,化学结构平面图具有反映时空演化四维信息的能力。     

云南弥渡宝兴厂金矿床成矿模式

宝兴厂矿区地质构造复杂,成矿条件有利。区内北东向响水断裂带是主要的控岩和控矿构造。三类金矿床分别在斑岩成矿期、热液成矿期和表生成矿期成生。文中建立相应的成矿模式。     

Impacts of macroalgal spores on the dynamics of adult macroalgae in a eutrophic estuary: high versus low hydrodynamic seasons and long-term simulations for global warming scenarios

A model describing macroalgal early life stages and adult dynamics was used to quantify the effects of non-adult forms on the productivity of adult macroalgae in a eutrophic estuary. Predictions indicate that during years with mild winters and low rainfall, spring blooms will occur at the expense of the growth and reproduction of overwintering adults and without the contribution of the spore bank. In these circumstances, there is a positive correlation between the intensity of the blooms and the biomass of overwintering adults until a maximum threshold value. On the contrary, in years with high rainfall and low or inexistent biomass of overwintering adults, the onset of adult’s growth depends on the biomass of viable dormant spores, the growing season occurs later and adult productivity is very limited. Long-term predictions for climate change scenarios suggest that, in general, global warming will have adverse affects on Ulva intestinalis productivity, with the adults being more affected than the early life stages.     

历史解译知识引导下组合遥感图谱特征的变化检测方法

高空间分辨率遥感影像为地表变化监测提供了大量细节信息,这使得基于高分辨率影像的变化检测技术成为当前遥感领域的研究热点之一。本文提出了一种历史解译知识引导下组合遥感图谱特征的变化检测方法。首先,通过分割前后时相的组合影像构建空间位置一致的对象,并在提取对象光谱和纹理特征后,引入前期土地覆盖专题图指导2类图谱特征相似度的DS证据融合;然后,利用其历史存档图斑所属区域的优势地类标签指示不同特征相似度的证据差异融合;最后,基于GMM（Gaussian Mixture Mode）模型的二值化方法提取最终的变化区域。实验结果表明,该方法能充分利用历史解译知识指导不同时相高分辨率影像对象特征相似度组合,一定程度上提高了变化检测正确率。