非均匀陆面条件下区域蒸散量计算的遥感模型

非均匀陆面条件下的区域蒸散计算是一个复杂的问题。文中首先在利用遥感资料求取地表特征参数 (如植被覆盖度、地表反照率等 )的基础上 ,建立了裸露地表条件下的裸土蒸发和全植被覆盖条件下植被蒸腾计算模型 ,然后结合植被覆盖度 (植被的垂直投影面积与单位面积之比 )给出非均匀陆面条件下的区域蒸散计算方法。实测资料验算表明该模型具有较高的计算精度。文章最后利用该模型对中国北方地区的蒸散量进行了计算 ,并对该研究区蒸散的特点进行了分析     

Implications of the relationship between catchment vegetation type and the variability of annual runoff

The impact of changing catchment vegetation type on mean annual runoff has been known for some time, however, the impact on the variability of annual runoff has been established only recently. Differences in annual actual evapotranspiration between vegetation types and the potential effect of changing vegetation type on mean annual runoff and the variability of annual runoff are briefly reviewed. The magnitude of any change in the variability of annual runoff owing to a change in catchment vegetation type is related to the pre‐ and post‐change vegetation types and the seasonality of precipitation, assuming that the variability of annual precipitation remains constant throughout. Significant implications of the relationship between vegetation type and the variability of annual runoff are presented and discussed for water resource management, stream ecology and fluvial geomorphology. Copyright © 2002 John Wiley & Sons, Ltd.     

不同参考椭球体的GIS数据转换探讨

通过一项工程和不同参考椭球转换软件的实现过程,探讨了不同参考椭球GIS数据的转换问题.首先介绍了转换的数学模型和软件的实现过程.其次介绍了几种转换方法,并通过一个工程实例介绍了具体的操作步骤.最后对这个工程实例进行了可行性分析.     

Fitness-for-Purpose of Reference Material Reference Values in Relation to Traceability of Measurement, as Illustrated by USGS BCR-1, NIST SRM 610 and IAEA NBS28

As in all fields of sample analysis, reference materials play a large role in supporting measurements in the geosciences. While a rather large number of materials are in distribution (> 380), not all are equally effective or fit-for-purpose in supporting laboratory data quality and thereby assuring the desired comparability of measurements between laboratories. Equally important, reference values that are not fit-for-purpose cannot be used effectively to establish traceability links between laboratory measurements and national and international standards. The needed fitness-for-purpose is not achieved for reference values either when more than one reference value has been proposed and a consensus does not exist among users as to which should be used by all, or when reference value uncertainties are too large in comparison to those of routine laboratory measurements. The focus of this review will be, first to outline the current reality, and second to suggest ways in which certifications of RMs can be improved to provide reference values that are universally accepted and more fit-for-purpose in general laboratory use. The discussion will be illustrated largely by current uses of USGS BCR-1, NIST SRM 610 and IAEA NBS28, as these three materials are those for which the largest body of newly published data exists, according to recent bibliographies of the geoanalytical literature published annually in Geostandards Newsletter: The Journal of Geostandards and Geoanalysis.     

Preparation of a New Geological Survey of Japan Geochemical Reference Material: Coral JCp-1

A new geochemical reference material, coral Porites sp. JCp-1 has been prepared by the Geological Survey of Japan (GSJ). Provisional values for twenty one major, minor and trace elements are presented. The homogeneity tests showed that all elements studied are considered to be homogeneously distributed.     

Evapotranspiration from citrus trees growing in sandy soilunder drip irrigation with saline water

An experiment on evapotranspiration from citrus trees under irrigation with saline waterwas carried out for 4 months. Two lysimeters planted with a citrus tree in the green house wereused. One lysimeter was irrigated with saline water (NaCl and CaCl2 of 2000 mg/L equivalence,EC = 3.8 dS/m, SAR = 5.9) and the other was irrigated with freshwater using drip irrigation. Theapplied irrigation water was 1.2 times that of the evapotranspiration on the previous day.Evapotranspiration was calculated as the change in lysimeter weight recorded every 30 minutes.The lysimeters were filled with soil with 95.8% sand. The results of the experiment were as follows.(i) The evapotranspiration from citrus tree was reduced after irrigation with saline water. Theevapotranspiration returns to normal after leaching. However it takes months to exhaust the saltfrom the tree. ( ii ) To estimate the impact of irrigation with saline water on the evapotranspirationfrom citrus trees, the reduction coefficient due to salt stress (Ks) was used in this experiment.Evapotranspiration under irrigation with saline water (ETs) can be calculated from evapotranspira-tion under irrigation with freshwater (ET) by the equation ETs = Ks× ET. Ks can be expressed as afunction of ECsw. (iii) The critical soil-water electrical conductivity (ECsw) is 9.5 dS/m, beyondwhich adverse effects on evapotranspiration begin to appear. If ECsw can be controlled at below9.5 dS/m, saline water can be safely used for irrigation.     

Chemical equilibria of thermal waters for the application of geothermometers from the Guanzhong basin, China

In this study, representative samples from thermal wells and springs were chemically analyzed and geothermometers were used to calculate the deep temperatures of geothermal reservoirs on the basis of water–mineral equilibrium. In some cases, however, the chemical components are not in equilibrium with the minerals in the reservoir. Therefore, log(Q/K) diagrams are used to study the chemical equilibrium for the minerals that are likely to participate. The Na–K–Mg triangular diagram is also applied to evaluate the equilibrium of water with reservoir rocks. Standard curves at the reference temperatures are prepared to reveal which type of silica geothermometer is appropriate for the specified condition. This study shows that water samples from geothermal wells W9 and W12 are in equilibrium with the selective minerals, and chalcedony may control the fluid–silica equilibrium. It is estimated that there is an exploitable low-temperature reservoir with possible temperatures of 80–90°C in the Guanzhong basin.     

国际地磁参考场在我国地磁基础研究中的应用

国际地磁参考场资料在我国得到广泛应用。利用国际地磁参考场资料，我国学者研究了高斯分析、地球磁场模型及其源场可能位置、重磁关系、核幔耦合、地磁场能量、地球非偶极子磁场西向漂移等。在绘制中国地磁等值图中也利用了某些国际地磁参考场资料。     

阿拉尔灌区棉田蒸散量计算模型

根据2000年阿克苏水平衡站有底测坑试验资料，分析了土壤水分有效性函数与土壤相对有效含水率，作物生物学特性函数，与群体叶面积指数的关系，结果表明：（1）土壤水分有效性函数与土壤相对有效含水率呈直线函数关系；（2）作物生物学特性函数与群体叶面积指数呈指数函数关系。选用20cm蒸发器水面蒸发量、作物生物学特性函数和土壤水分有效性函数，应用数理统计方法建立了阿拉尔灌区棉田蒸散量计算模型。该模式仅需常规气象与土壤湿度资料，计算简便，精度较高，便于在缺乏实测资料的地区使用。     

贡嘎山东坡亚高山森林区蒸散力的估算

以海螺沟 30 0 0m气象站的观测资料为基础 ,运用Penman公式法　空气饱和差法和桑斯维特公式法 ,计算了贡嘎山东坡亚高山林林的年平均蒸散力 ,其结果为分别为 431 81mm、171 4mm和 44 6 4mm。通过分析蒸散力的影响因素 ,对这三种计算蒸散力的方法作了比较 ,对计算结果存在的差异作了比较合理的解释 ,认为用Penman公式法可以估计出本研究区的蒸散力。同时 ,对蒸散力及其影响因自进行了相关分析 ,指出湿度和风不是速制约研究区蒸散力的主导因子 ,并分析了蒸散力与水面蒸发的关系 ,由此推导出估算蒸散力的简便方程 :PE =6 6 77 0 6 91E60 1 0 75 1ITm 0 0 396Pm。