区域化变量的空间聚类分析

传统的聚类分析方法利用数据对平均值的偏差，研究变量之间的相互关系。当它应用于区域化变量的分类时，因缺乏对区域化变量的空间结构的考虑，对合理解释区域化变量之间的相互关系不利。空间聚类分析方法比较好地解决了这个问题。本文介绍了该方法的基本原理及其算法，并说明了它在非条件模拟及在某矿区中的应用情况     

A preliminary study of the effects of some flow parameters in the generation of poloidal and toroidal energies within a 3-D spherical thermal-convective system with variable viscosity

The effects of variable viscosity on flow dynamics within spherical shells are investigated using a finite-element thermal convection model, and preliminary result for cases with relatively low Rayleigh numbers and small viscosity contrasts are reported. These results demonstrate some general effects of viscosity variation on mantle dynamics, and, in particular, the generation of toroidal energy. Since lateral viscosity variations are necessary in the generation of toroidal motion in a thermally driven convective system, it is not surprising our results show that flows with greater viscosity contrasts produce greater amounts of toroidal energy. Our preliminary study further shows that solutions become more time-dependent as viscosity contrasts increase. Increasing the Rayleigh number is also found to increase the magnitude of toroidal energy. Internal heating, on the other hand, appears to lead to less toroidal energy compared wth bottom heating because it tends to produce a thermally more uniform interior and thus smaller viscosity variations.     

山地边界层中场变量的动力学研究

采用与实测较接近的二次函数来表达Ｅｋｍａｎ层中的湍流粘性系数Ｋ，在圆形气压场条件下，求得了山地上空边界层中的风速，进而求得散度、涡度和垂直速度等场变量随高度的分布。并作图分析了这些场变量的一些动力学特征。改进了以往在求解析解时，略去运动方程中湍流粘性力项中的关于高度的一阶导数项，以及取山坡面上风速为零作下边界条件等欠合理欠精确的做法。所求得的风速、散度、涡度和垂直速度均用简单的初等函数表示出来，有助于边界层参数化和深化对边界层动力学的认识。     

Chironomids as indicators of climate change: a 100‐lake training set from a subarctic region of northern Sweden (Lapland)

Multivariate numerical analyses (DCA, CCA) were used to study the distribution of chironomids from surface sediments of 100 lakes spanning broad ecoclimatic conditions in northern Swedish Lapland. The study sites range from boreal forest to alpine tundra and are located in a region of relatively low human impact. Of the 19 environmental variables measured, ordination by CCA identified mean July air temperature as one of the most significant variables explaining the distribution and the abundance of chironomids. Lossonignition (LOI), maximum lake depth and mean January air temperature also accounted for significant variation in chironomid assemblages. A quantitative transfer function was created to estimate mean July air temperature from sedimentary chironomid assemblages using weightedaveraging partial least squares regression (WAPLS). The coefficient of determination was relatively high (r² = 0.65) with root mean squared error of prediction (RMSEP, based on jack-knifing) of 1.13 °C and maximum bias of 2.1 °C, indicating that chironomids can provide useful quantitative estimates of past changes in mean July air temperature. The paper focuses mainly on the relationship between chironomid composition and July air temperature, but the relationship to LOI and depth are also discussed.     

新一代天气雷达

阐述了双偏振多普勒雷达的理论基础，以ＣＳＵ－ＣＨＩＬＬＳ波段双偏振多普勒天气雷达为例，介绍了双偏振多普勒雷达的系统结构和工作原理。并以雷达测量的数据处理和分析实例说明了双偏振多普勒雷达在气象学中的应用     

A STUDY ON THE VARIATIONS OF ANNUAL FREQUENCY FOR TROPICAL CYCLONE IN NORTHWEST PACIFIC DURING THE LAST HUNDRED YEARS

In this paper, a study on the variation of annual frequency of tropical cyclone (TC) and its relation with SST, Southern Oscillation index, sunspot relative number and number of days for specific circulation patterns was made by using 1884-1988 data of annual frequency for Northwest Pacific TC occurrence, which had been corrected to tendencies.Preliminary results indicated that in the variation of annual TC frequency there exist obvious p.6riods of 21, 31, 15 and 6 years and sustaining periods lasting 12 years in average.Well-defined processes of inflexion were observed in 1931, 1959 and 1977 over the past hundred years.The results also suggested insignificant statistic tendency of annual TC frequency increasing (decreasing) in winter/spring (summer/autumn )in the El Nino years.When the stratosphere was in the zonally westerly phase, the northern zonal circulation would abnormally develop and solar activity would enhance to favour the generation and development of TC.     

STUDY ON CANONICAL AUTOREGRESSION PREDICTION OF METEOROLOGICAL ELEMENT FIELDS*

Through extension of canonical correlation to the analysis of meteorological element fields (MEF), a concept from combination of canonical autocorrelation with canonical autoregression (CAR) is developed for short-term climatic prediction of MEFs with a formulated scheme. Experimental results suggest that the scheme is of encouraging usefulness to a weak persistence MEF,i.e., rainfall field and, in particular, to a strong persistance one like a SST field.     

基于ArcGIS的滑坡空间分布的变维分形研究——以江西省宁都县为例

滑坡空间分布的定量研究对了解滑坡的发育特征具有实际意义，能够为滑坡的防治提供重要依据.为了了解滑坡的空间分布特征，以江西省宁都县1：5万地质灾害调查数据为基础，基于ArcGIS空间分析叠加模块，对滑坡空间分布规律应用变维分形理论进行定量研究，揭示出滑坡空间分布与地形地貌、岩土体类型、高程、坡度均呈二价累计和分形分布，使得滑坡与各因素之间的关系从定性分析上升到定量研究，并计算出分维值，说明了分维值的意义.