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统计1961~1990年南阳降水资料结果显示,南阳春旱发生的机率为52%,且自60年代,以来春旱出现的机率有增大的趋势。在分析春旱环流形势的基础上,选择相当系数较高的环流因子组合,分两个阶段建立了春旱预报方程,经1995~1996年业务中试用,两个阶段的预报方程准确率分别为50%和100%。 相似文献
33.
Russell M Webster L Walsham P Packer G Dalgarno EJ McIntosh AD Moffat CF 《Marine pollution bulletin》2005,50(6):638-651
Due to the potentially accumulative nature of the Fladen Ground, an area of intense oil activity in the North Sea, a survey was carried out in 1989 to map the distribution of contamination in relation to these oil activities. All the sediments collected were screened by ultraviolet fluorescence (UVF) for polycyclic aromatic hydrocarbons (PAHs) and selected samples were analysed for n-alkanes (by GC-FID), PAHs and biomarkers (by GC-MSD). This survey was repeated in 2001, with all the 1989 sites being resampled. All of these sediments were analysed for UVF oil equivalents, PAHs, n-alkanes and biomarkers. The concentrations of these parameters decreased between 1989 and 2001, with average decreases ranging from 43% to 88%. In addition, no significant difference was found, for all the parameters, between near field (<5 km from an oil installation) and far field (>5 km from an oil installation) sites in 2001 indicating that the Fladen Ground is approaching a 'steady state' or background concentration for contamination. 相似文献
34.
Remote sensing of coral reefs and their physical environment 总被引:11,自引:0,他引:11
Mumby PJ Skirving W Strong AE Hardy JT LeDrew EF Hochberg EJ Stumpf RP David LT 《Marine pollution bulletin》2004,48(3-4):219-228
There has been a vast improvement in access to remotely sensed data in just a few recent years. This revolution of information is the result of heavy investment in new technology by governments and industry, rapid developments in computing power and storage, and easy dissemination of data over the internet. Today, remotely sensed data are available to virtually anyone with a desktop computer. Here, we review the status of one of the most popular areas of marine remote sensing research: coral reefs. Previous reviews have focused on the ability of remote sensing to map the structure and habitat composition of coral reefs, but have neglected to consider the physical environment in which reefs occur. We provide a holistic review of what can, might, and cannot be mapped using remote sensing at this time. We cover aspects of reef structure and health but also discuss the diversity of physical environmental data such as temperature, winds, solar radiation and water quality. There have been numerous recent advances in the remote sensing of reefs and we hope that this paper enhances awareness of the diverse data sources available, and helps practitioners identify realistic objectives for remote sensing in coral reef areas. 相似文献
35.
Ribeiro AP Figueira RC Martins CC Silva CR França EJ Bícego MC Mahiques MM Montone RC 《Marine pollution bulletin》2011,62(1):192-196
Admiralty Bay (Antarctica) hosts three scientific stations (Ferraz, Arctowski and Macchu Picchu), which require the use of fossil fuel as an energy source. Fossil fuels are also considered the main source of pollution in the area, representing important inputs of major pollutants (organic compounds) and trace metals and metalloids of environmental interest. Accordingly, this work presents the results of As, Cd, Cr, Cu, Ni, Pb and Zn in sediment profiles from Admiralty Bay. The sediment results from Ferraz station were slightly higher than the other sampling sites. The highest contents were observed for Cu and Zn (from 44 to 89 mg kg−1). Otherwise, by using enrichment factors and geochronology analysis, the most relevant enrichment was observed for As in the samples collected close to the Ferraz station, indicating that increasing As content may be associated with the activities associated with this site. 相似文献
36.
对平乐站1957~2003年夏季实况资料进行分析,阐述了当地夏季高温干旱天气分布概况,分析了夏季高温干旱天气的天气背景。 相似文献
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A new procedure is presented for the analysis of slug tests performed in partially penetrating wells in formations of high hydraulic conductivity. This approach is a simple, spreadsheet-based implementation of existing models that can be used for analysis of tests from confined or unconfined aquifers. Field examples of tests exhibiting oscillatory and nonoscillatory behavior are used to illustrate the procedure and to compare results with estimates obtained using alternative approaches. The procedure is considerably simpler than recently proposed methods for this hydrogeologic setting. Although the simplifications required by the approach can introduce error into hydraulic-conductivity estimates, this additional error becomes negligible when appropriate measures are taken in the field. These measures are summarized in a set of practical field guidelines for slug tests in highly permeable aquifers. 相似文献
39.
本文对大别群的微古植物组合特征及其时代作了分析,并根据沉积建造,变质作用、含矿性及地层接触、同位素年龄等方面的资料,对大别群与邻区相当地层的对比问题,提出了自已的认识。 相似文献
40.
1 前言。麦播期(9月21日至10月20日)降水的多少、时空分布均匀与否,直接影响着最佳适播期。历年来因干旱或雨涝而推迟适时播种,都对我区小麦产量造成很大影响.因此,寻找麦播期降水变化的规律,加强对旱涝灾害的研究,为政府各级领导的防灾抗灾提供科学依据,具有十分重要的意义。 相似文献