Hurricane forecasts in the FSU models

A brief account of our studies on the hurricane forecast problem is presented here. This covers recent prediction results from the Florida State University (FSU) regional and global numerical weather prediction models. The re-gions covered are the Indian and the Pacific Oceans. The life cycle of the onset vortex (a hurricane) of the summer monsoon, typhoons over the western Pacific Ocean and tropical cyclones over the Bay of Bengal (Andhra Pradesh and the Bangladesh storms) are covered here. The essential elements in the storm formaton are the strong horizontal shear in the cyclogenetic areas, a lack of vertical shear and warn sea surface temperatures. The storm motion has a steering component largely described by the advection of vorticity by a vertically averaged layer mean wind, the recurvature of a storm appears to invoke physical processes via the advection of divergence by the divergent part of the wind especially in the outflow layers of the storm. Very high resolution global models seem to be able to handle the motion and structure during the entire life of typhoons quite reasonably. The scope for better diagnosis of the storms life cycle appears very promising in view of the realistic simulation of the life cycle.     

一种新的遥感影象快速分类器

1 引言在遥感影象数据分析中,最重要的任务之一就是把影象数据分成不同的地物类型,如土壤、水体和岩石等。在与政策有关的情况下,可能还需要诸如淹没面积,某种作物面积或海岸线长度这样一些准确的定量信息。这种准确的定量信息只有通过使用模式识别(PR)法则才能获得(Tou和Gonzales 1974)。实际上,影象分类是在纯场地和纯象元基础两种情况下实现的。纯场地分类,是将一个小的均一地区(一组彼此相邻的象元)看作所有象元均具有某种状况来进行分类。这类分类器最适于农田和林地的分类,因为就农田和林地的开阔性来说均一区     

A TEST OF SIGNIFICANCE FOR PARTIAL LEAST SQUARES REGRESSION

Partial least squares (PLS) regression is a commonly used statistical technique for performingmultivariate calibration, especially in situations where there are more variables than samples. Choosingthe number of factors to include in a model is a decision that all users of PLS must make, but iscomplicated by the large number of empirical tests available. In most instances predictive ability is themost desired property of a PLS model and so interest has centred on making this choice based on aninternal validation process. A popular approach is the calculation of a cross-validated r~2 to gauge howmuch variance in the dependent variable can be explained from leave-one-out predictions. Using MonteCarlo simulations for different sizes of data set, the influence of chance effects on the cross-validationprocess is investigated. The results are presented as tables of critical values which are compared againstthe values of cross-validated r~2 obtained from the user's own data set. This gives a formal test forpredictive ability of a PLS model with a given number of dimensions.     

成岩不同阶段碳氢化合物的运移与聚集

碳氢化合物(HC)的运移与富集发生在地质、热力学和地化条件变化的不同成岩阶段。对近代海洋沉积物的调查发现,在沉积物沉积阶段就开始了碳氢化合物的运移与聚集过程。据北极区深海钻探600m处的资料,那里存在把生物成因气转变为气水合物的有利条件。气水合物层的分布面积往往超过100000km~2。     

石英、钠长石、钙长石、方解石中的氧同位素分馏

在t≥600℃的温度条件下,通过硅酸盐和方解石之间的无水交换,用实验测定了石英、钠长石、钙长石、方解石中的乎衡氧同位素分馏.这些体系中的氧同位素交换就象硅酸盐和水之间的交换那么快.分馏系数可概括为的△Q-Cc=×0.8310~6/t~2;△Ab-Cc=－0.57×10~6/t~2;△An-Cc=－1.59×10~6/t~2.从这些方程式很容易得到硅酸盐矿物对的分馏系数。将这些结果与热液实验所得到     

从空间估算全球降水

1.对降水测量的需求 1.1 气候监测与研究为检验大气环流模式(GCM),需要全球降水测量资料。再现观测到的降水分布的能力是这种模式性能的一个灵敏指标。全球降水有2/3落在热带和副热带,与此关联的潜热是热带环流的一个主要驱动力。在热带,大部分入射太阳辐射在海洋上被吸收。这部     

遥感图像上复杂地质模式的计算机辅助解译

本文介绍了一种用于辅助遥感图像地质解译的方法概况,所开发的方法是应用数学形态学对分类图像进行分析的技术。为了说明有关这类辅助解译的两种处理方法,使用了某一地质褶皱实例。