Stable isotope values of Costa Rican surface waters   总被引：3，自引：0，他引：3  

Matthew S. Lachniet  William P. Patterson 《Journal of Hydrology》2002,260(1-4):135-150

Stable isotope data of surface waters from the humid tropics in general, and Costa Rica in particular, are scarce. To improve our understanding of the spatial distribution of stable isotopes in surface waters, we measured δ¹⁸O and δD in river and lake (n=63) and precipitation (n=3) samples from Costa Rica. We also present data from the IAEA/WMO isotopes in precipitation network as context for our study. Surface water isotope values do not strongly correlate with elevation, stream head elevation, stream length, distance from Caribbean Sea, or estimated mean annual precipitation for the country as a whole. However, the data show distinct regional trends. The δ¹⁸O and δD values downwind of mountain ranges are inversely related to the altitude of the ranges the air masses traverse. In the lee of the high Talamanca Range, δ¹⁸O values are 6–8‰ lower, while in the lee of the lower Tilarán Range δ¹⁸O values are 2–3‰ lower than upwind sites along the Caribbean Slope. An altitude effect of −1.4‰ δ¹⁸O/km is present on the Pacific slope of southern Costa Rica, equivalent to a temperature effect of −0.3‰/°C. The Nicoya and Osa Peninsulas have higher values than upwind sites, suggesting input of Pacific-sourced moisture, evaporative enrichment, or decreased condensation temperatures. Elevated and increasing d-excess values inland along the Nicaragua Trough suggest a recycled component may be an important contributor to the water budget. These data provide preliminary stable isotope information for Costa Rica, and will benefit paleoclimatic research in the region. More detailed studies would be beneficial to our understanding of the controls on stable isotope composition of tropical waters.  相似文献   

2001年11月14日新疆-青海交界8.1级地震   总被引：3，自引：0，他引：3  

陈学忠  许力生 《国际地震动态》2002,(3):1-4

简要介绍了2001年11月14日新疆－青海交界8．1级地震的预测情况，给出了中、美、日等对此次地震的震源参数测定和震源机制，以及余震的分布和加卸载响应比随时间的变化。进而对震区近期地震趋势进行预测。  相似文献   

Locating and quantifying the seismic discontinuities in a complex medium through the migration and AVA analysis of reflected and converted waves: an application to the Mt Vesuvius volcano     

E. Auger  J. Virieux  A. Zollo 《Geophysical Journal International》2003,152(2):486-496

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Shear wave statics using receiver functions   总被引：1，自引：0，他引：1  

D. van Manen  J. O. A. Robertsson  A. Curtis  R. Ferber  H. Paulssen 《Geophysical Journal International》2003,153(3):F1-F5

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Book Reviews     

《The Professional geographer》2003,55(4):528-529

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PowerBuilder 8.0中C/S模式应用过渡到B/S模式应用的实现技术   总被引：1，自引：0，他引：1  

李军  罗省贤 《物探化探计算技术》2003,25(2):188-192

简要分析了PowerBuilder 8．0中各种B/S解决方案的优劣，探讨了适用于已有C／S模式应用过渡到B／S模式应用的实现方法，以及利用ASP技术实现对不同类型的客户测览器隐藏底层实现方法的技术，并给出了C／S模式应用过渡到B／S模式应用的一个实例。  相似文献   

济阳坳陷横波速度研究及应用   总被引：1，自引：0，他引：1  

李红梅  韩文功 《物探与化探》2003,27(5):362-365

随着多波勘探的发展,横波已越来越多地应用在实际勘探生产中,横波速度参数研究对于指导勘探是十分必要的.笔者利用纵横波VSP测井得到的纵横波速度,根据最小平方误差建立的速度模型,建立了济阳坳陷的纵波、横波、转换波速度参数,应用转换波速度参数提高了盐家地区的多波资料解释精度;利用多种资料总结出纵横波速度关系,为本区今后开展多波勘探提供基础资料.  相似文献   

数字地籍测绘实施中的技术问题     

段莉  杨晓明 《测绘与空间地理信息》2003,26(2):29-30

数字地籍测绘是目前土地管理部门的首选方案,需要制定街坊划分、界址线设定、工作底图与采集草图一体化作业、数据文件管理、街坊线、图斑的绘制等技术措施。  相似文献   

Paleoclimate reconstruction based on the timing of speleothem growth and oxygen and carbon isotope composition in a cave located in the rain shadow in Israel     

Anton VaksMiryam Bar-Matthews  Avner AyalonBettina Schilman  Mabs GilmourChris J Hawkesworth  Amos FrumkinAaron Kaufman  Alan Matthews 《Quaternary Research》2003,59(2):182-193

High-resolution ²³⁰Th/²³⁴U ages and δ¹⁸O and δ¹³C compositions of speleothems in Ma’ale Efrayim Cave located to the east of the central mountain ridge of Israel enable us to examine the nature of the rain shadow aridity during glacial and interglacial intervals. Speleothem growth occurred during marine glacial isotopic periods, with no growth during the two last marine isotope interglacial intervals and during the peak of the Last Glacial Maximum. This contrasts with speleothem growth in caves located on the western flank of the central mountain ridge, in the Eastern Mediterranean semiarid climatic zone, which continued throughout the last 240,000 yr. Thus, during glacial periods water reached both sides of the central mountain ridge. A comparison of the present-day rain and cave water isotopic compositions and amounts at the Ma’ale Efrayim Cave site with those on the western flank shows that evaporation and higher temperatures on the eastern flank are major influences on isotopic composition and the lack of rainfall. The δ¹⁸O and δ¹³C profiles of the speleothems deposited between 67,000 and 25,000 yr B.P. match the general trends of the isotopic profiles of Soreq Cave speleothems, suggesting a similar source (eastern Mediterranean Sea) and similar climatic conditions. Thus, during glacial periods the desert boundary effectively migrated further south or east from its present-day location on the eastern flank, whereas interglacial periods appear to have been similar to the present, with the desert boundary at the same position. The decrease in overall temperature and a consequent reduction in the evaporation to precipitation ratios on the eastern flank are viewed as the major factors controlling the decay of the rain shadow effect during glacial periods.  相似文献   

地震资料小波剖面制作系统     

崔若飞  李晋平 《地球物理学进展》2003,18(3):562-566

对不同的小波变换算法和小波基函数进行了研究，得到了适用于地震资料处理的最佳小波基函数，并用Visual C 语言开发了基于Windows操作平台下的地震资料小波剖面制作系统。利用小波剖面制作系统和最佳小波基函数对煤田实际地震资料进行了处理，取得了令人满意的地质效果。  相似文献