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111.
针对我军当前装甲车辆鉴定定型试验中,沙漠戈壁地区适应性试验考核试验覆盖度较低、考核强度不足、试验标准老旧等问题,导致作战效能大幅下降,甚至无法满足作战使用要求。在参照当前传统的严寒、湿热、高原地区适应试验组织方法基础上,结合当前复杂环境试验及边界条件考核要求,分析了沙漠戈壁地区敏感环境因素,提出了2种新型试验方法,一是“基础+复杂”组合的沙漠戈壁地区适应性试验方法,二是基于作战使用任务剖面循环的试验方法,进一步提升试验考核强度及深度,为装甲车辆沙漠戈壁地区适应性试验开展提供了设计新思路。  相似文献   
112.
ABSTRACT: A procedure using detrended kriging has been developed to calculate daily values of mean areal precipitation (MAP) for input to hydrologic models. The important features of this procedure that overcome weaknesses in existing MAP procedures are: (1) specific precipitation-elevation relationships are determined for each time period as opposed to using relationships based on climatological averages, (2) spatial variability is incorporated by estimating precipitation for each grid cell over a watershed, (3) the spatial correlation structure of precipitation is explicitly modeled, and (4) station weights for precipitation estimates are determined objectively and optimally. Detailed cross-validation testing of the procedure was done for the Reynolds Creek research watershed in southwestern Idaho. The procedure is suitable for use in operational streamflow forecasting.  相似文献   
113.
根据对河西走廊中部荒漠植被的调查,对荒漠植被进行了分类及生态学描述,重点讨论了荒漠植被对改善河西走廊中部农村生态环境的作用,提出了保护和利用荒漠植被的措施及改善生态环境的途径。  相似文献   
114.
ABSTRACT: Forest land managers are concerned about the effects of logging on soil erosion, streamflow, and water quality and are promoting the use of Best Management Practices (BMPs) to control impacts. To compare the effects of BMP implementation on streamwater quality, two of three small watersheds in Kentucky were harvested in 1983 and 1984, one with BMPs, the other without BMPs. There was no effect of clearcutting on stream temperatures. Streamflow increased by 17.8 cm (123 percent) on the BMP watershed during the first 17 months after cutting and by 20.6 cm (138 percent) on the Non-BMP watershed. Water yields remained significantly elevated compared to the uncut watershed 8 years after harvesting. Suspended sediment flux was 14 and 30 times higher on the BMP and Non-BMP Watersheds, respectively, than on the uncut watershed during treatment, and 4 and 6.5 times higher in the 17 months after treatment was complete. Clearcutting resulted in increased concentrations of nitrate, and other nutrients compared to the uncut watershed, and concentrations were highest on the non-BMP watershed. Recovery of biotic control over nutrient losses occurred within three years of clearcutting. The streamside buffer strip was effective in reducing the impact of clearcutting on water yield and sediment flux.  相似文献   
115.
ABSTRACT: Detailed studies of the surface hydrology of reclaimed surface-mined watersheds for both rainfall and snowmelt events are non-existent for central Alberta yet this information is crucial for design of runoff conveyance and storage structures. A study was initiated in 1992 with principal objectives of quantifying surface runoff for both summer rainfall and spring snowmelt events and identifying the dominant flow processes occurring in two reclaimed watersheds. Snowmelt accounted for 86 and 100% of annual watershed runoff in 1993 and 1994, respectively. The highest instantaneous peak flow was recorded during a summer rainfall event with a return period of greater than 50 years. Infiltration-excess overland flow was identified as the dominant flow process occurring within the Sandy Subsoil Watershed, whereas saturation overland flow was the principal runoff process occurring within the West Watershed.  相似文献   
116.
ABSTRACT. Estimates of peak flows, with specified return periods, are needed in practice for the design of works that affect streams in forested areas. In the province of British Columbia (B.C.), Canada, the new Forest Practices Code specifies the 100-year instantaneous peak flow (Q100) for the design of bridges and culverts for stream crossings under forest roads; and many practitioners are engaged in making such estimates. The state of the art is still quite primitive, very similar to the state of urban hydrology 30 years ago, when popular estimating techniques were used with little consideration given to their applicability. Urban hydrology then evolved on a much more scientific basis, such that within about a 10-year period, standard approaches to design were developed. Forest hydrology should follow the same pattern, at least as far as estimating design flows is concerned. Popular present day design procedures include the rational method and other empirical approaches based on rainfall data, as use of the standard flood frequency approach is limited by the paucity of relevant flow data. Estimating procedures based on peak streamflow measurements and statistics are likely to evolve, and these will include distinctions for rain, snowmelt, and rain on snow floods. Guidelines will also be developed for selecting and applying appropriate procedures for particular areas.  相似文献   
117.
ABSTRACT: This paper explores a range of forest hydrology issues and identifies my concepts of the field's most pressing research needs. I extend the topic to include teaching and education in the broader sense because current teaching is usually part of the researcher's portfolio and because education involves that of both the research scientist and a broader audience. I consider the primary research, education, and service roles of the forest hydrologist also within a range of domains or, as I prefer to identify them, scales: (1) the molecular or pore level; (2) hydrological process; (3) watershed function; (4) global considerations, and (5) the human dimension which, while not actually a scale itself, embraces, is important to, and is affected by the first four. All are topics screaming for attention by researchers, educators, and practitioners. I shall here focus on the middle three.  相似文献   
118.
城镇生活污水排入水体 ,严重影响水资源的使用价值。沙漠地区因缺水 ,造成许多地方造林失败。本文提出了将城镇生活污水就近引浇防沙治沙工程林的构想 ,并从经济和环境影响两个方面详细论述了该方案的比较优势  相似文献   
119.
本文通过对中国地形及气候特征的讨论 ,提出沙漠治水 ,水治沙漠的观点 ,为中国及其他国家的污水治理 ,提供一种新的思路和建议  相似文献   
120.
2006年夏季,经对全区各生态类型区实地调研:干旱程度普遍高,湖泊集水线急剧向心退缩或湖泊干涸,湖泊萎缩、河流湿地退化特征明显;进入6、7月中旬,大范围、大面积草原土地处于裸露状态,沙源丰富,草原返青尚无从谈起;荒漠草原上迅猛发展的露天矿开发,裸露外排土场成为新的人为沙尘源。本文定性报告了内蒙古草原新增沙尘源现状。  相似文献   
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