Paleo-pole positions from martian magnetic anomaly data

Magnetic component anomaly maps were made from five mapping cycles of the Mars Global Surveyor's magnetometer data. Our goal was to find and isolate positive and negative anomaly pairs which would indicate magnetization of a single source body. From these anomalies we could compute the direction of the magnetizing vector and subsequently the location of the magnetic pole existing at the time of magnetization. We found nine suitable anomaly pairs and from these we computed paleo-poles that were nearly equally divided between north, south and mid-latitudes. These results suggest that during the existence of the martian main magnetic field it experienced several reversals and excursions.     

1998年夏季松花江、嫩江流域大暴雨中尺度雨团活动分析

用地面逐时降水资料、静止卫星云图、雷达图及常规气象资料,分析了８月上旬不同时段松花江及嫩江流域出现的中尺度雨团（≥５．０ｍｍ／ｈ）活动情况。根据它们的活动特点及在卫生云图、雷达回波上的演变和物理量诊断场的特征,将其分为两类。第１类是典型的冷涡中尺度雨团,第２类为东南方有地面气旋活动的冷涡中尺度雨团,它们都出现在冷涡的成熟及消亡阶段,活动在冷涡的不同部位,有着各自不同的演变特点。由此构建了相应的中尺     

TLM法在二维非均匀介质电磁场计算中的应用

传输线模型方法(Transm ission Line Modeling,TLM)是近年来发展起来的描述快速电磁场现象的分支。我们将TLM方法应用于二维介质电磁场的计算,并且详细地阐述了该算法的实现过程。在数值实验中,分别使用TLM法、有限差分法计算各向同性介质中的静电场的分布,通过对结果进行对比分析,证明了TLM方法具有较高的精度,并且用TLM方法计算电磁场相当直观。同时,还用TLM法计算了在二维非均匀各向同性介质中,点电流源情况下研究区域中的电位分布,其结果较为理想。     

OLR场对福建热带气旋频数影响的初步研究

根据１９７４～１９９７年卫星观测的ＯＤＲ（射出长波辐射）资料计算ＯＬＲ的特征量,用其表征ＩＴＣＺ和副热带高压的位置和强度,分析影响福建热带气旋（ＴＣ）年频数与ＩＴＣＺ和副热带高压的关系,结果表明,ＴＣ异常偏少（多）年,ＩＴＣＺ位置偏南（北）,强度偏弱（强）,年太平洋上的ＯＬＲ距平场配置相反,即ＴＣ异常偏少（多）年,西太平洋热带地区ＯＬＲ为正距平,而赤道中东太平洋为负（正）距平区。     

电偶源频率电磁测深中的静位移现象及视电阻率曲线的畸变

以电偶源频率电磁测深 (FEMS)二维数字模拟为例 ,从理论上简略讨论了波区定义的 5种视电阻率的变化特征及静位移现象 ,定性分析了表面局部水平非均匀体对视电阻率曲线畸变的影响 .     

用波函数展开法求解界面圆孔的SH波散射问题

研究了ＳＨ波绕界面圆孔散射的波函数展开理论。由入射,反射和透射波组成的自由波场与孔的散射场叠加成总波场。将定义于两个半平面的散射场按一定方式延拓到全平面。通过Ｈａｎｋｅｌ－Ｆｏｕｒｉｅｒ型积分来满足界面与孔缘处的边界条件,得到了确定特定系数的封闭代数方程组。给出了具体算例,计算了孔缘处的动应力系数分布。     

Application of nonlinear forecasting techniques for meteorological modeling

A nonlinear forecasting method was used to predict the behavior of a cloud coverage time series several hours in advance. The method is based on the reconstruction of a chaotic strange attractor using four years of cloud absorption data obtained from half-hourly Meteosat infrared images from Northwestern Spain. An exhaustive nonlinear analysis of the time series was carried out to reconstruct the phase space of the underlying chaotic attractor. The forecast values are used by a non-hydrostatic meteorological model ARPS for daily weather prediction and their results compared with surface temperature measurements from a meteorological station and a vertical sounding. The effect of noise in the time series is analyzed in terms of the prediction results.     

State-of-the art and perspectives of economic geography — taking stock from a German point of view

This article presents an evaluation of the current status of economic geography in general and German economic geography in particular with respect to research topics. A comparison with Anglo-American economic geography, more specifically, its actual research fields are also undertaken on the basis of a bibliometrical analysis of German and international journals dedicated to economic geography. On the basis of this analysis suggested actions are formulated, which could contribute to improved performance of research in German economic geography.