On the interpretation of recharge estimates from steady-state model calibrations

Ground water recharge is often estimated through the calibration of ground water flow models. We examine the nature of calibration errors by considering some simple mathematical and numerical calculations. From these calculations, we conclude that calibrating a steady-state ground water flow model to water level extremes yields estimates of recharge that have the same value as the time-varying recharge at the time the water levels are measured. These recharge values, however, are a subdued version of the actual transient recharge signal. In addition, calibrating a steady-state ground water flow model to data collected during periods of rising water levels will produce recharge values that underestimate the actual transient recharge. Similarly, calibrating during periods of falling water levels will overestimate the actual transient recharge. We also demonstrate that average water levels can be used to estimate the actual average recharge rate provided that water level data have been collected for a sufficient amount of time.     

Contamination by organochlorine compounds in sturgeons from Caspian Sea during 2001 and 2002

Organochlorine compounds (OCs) were determined in the five species of sturgeons collected from coastal waters of Caspian Sea in Kazakhstan, Azerbaijan, Turkmenistan and Iran during 2001 and 2002 to understand their status of contamination and accumulation features. Among OCs examined, concentrations of DDTs (DDT and its metabolites) were predominant in all the sturgeon samples with concentrations ranging from 73 to 31,000 ng/g on lipid weight basis, followed by PCBs, CHLs, HCHs, HCB, dieldrin, TCPMOH, and heptachlor epoxide in order. The concentrations of OCs in beluga (Huso huso) were the highest among all the five species. When comparing residue levels among same species, OC residues were highest in sturgeons from Azerbaijan and Kazakhstan and lowest in Turkmenistan. However, the concentrations of HCHs, dieldrin, and heptachlor epoxide in sturgeons showed less geographical variability.     

南太平洋上的副热带急流

文章的主要目的是要对存半年澳大利亚－南太平洋区域副热带对流层上层的西风最大区有一个更好的了解，过去的论文表明它的出现具有１－２周的周期性。该文的重点在于对前面提到的西风最大区的加速阶段中热带和温带强迫的相对重要性作一个定量分析。向外长波辐射，风数据以及分解为旋转和辐射分量的动能收支平衡，被用来探讨１９８５－１９８９年 夏季时段中强迫机制的重要性，制定了判据，用来判定纬向风的强加速阶段。总共找出４０     

地体学说的兴起及其意义

一、地体学说产生的背景自七十年代初期以来,随着大陆边缘构造研究的沉入开展和古地磁学方法的广泛使用,在北美科迪勒拉地区产生了构造地层地体(Tectonstratigraphic terrane)理论。这一学说的出现,引起了地质学家们的关注和兴趣。美、加、日等国学者共同努力,很快使研究工作扩展到了北起阿留中群岛,南至南极大陆的整个环太平洋地区。在原来认为均一的构造岩相带中,识别出了大小不等、性质不同的许多地体,成功地解释     

工程高边坡稳定性评价的信息量法

通过对８种因素、７７种状态的信息量计算，得出研究区稳定性信息的权值。在取得１２８个预测单元的信息量预测值之后，划分出５３个活动单元和较活动单元，其中１２个为新预测的不稳定区。与仪器观测结果比较，一些新预测区的不稳定性得到证实。研究表明，信息量法对评价工程高边坡稳定性，特别是消除工程隐患具有重要意义