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151.
江淮地区夏季羊舍小气候环境检测及评价 总被引:1,自引:1,他引:0
为了探明中国南方羊舍环境条件和存在的问题,在江淮地区选择南方最常见的双坡式漏缝地板有窗封闭羊舍,连续2a对其夏季最热月(7月)的空气环境指标进行了检测和分析,结果表明:1)该类羊舍最热月空气日平均温度、相对湿度、气流速度、光照强度、噪音与氨气质量浓度和二氧化碳体积分数分别为30.5℃、70.2%、0.16 m/s、99.45 lx、49.82 dB、1.98 mg/m3、0.060%,以上指标中,除日平均温度超标外,其他各项指标均符合环境卫生学标准;2)不同采样点(离地0.3、1、1.7 m)测定结果显示各参数(空气温度、相对湿度、氨气和二氧化碳浓度)夏季空间分布特征差异不显著;3)随着外界环境的变化,舍内空气温度和相对湿度有明显的日变化规律,而一月内的变化比较稳定,阴雨天降温幅度较大(6.9℃),试验期昼夜平均温差为2.3℃,舍内外平均温差为1.8℃;4)舍内氨气和二氧化碳浓度日、月变化幅度均较小;5)氨气浓度与空气温度和相对湿度之间存在显著的正相关性(r=0.8702,P<0.05)。综合评价认为,双坡式漏缝地板有窗封闭羊舍小气候环境基本符合环境卫生学标准和山羊的生物学特性要求,适宜在江淮地区推广应用,但在炎热的夏季需要采取一定的降温措施。该研究可为一般羊舍小气候环境的测定及参数评价提供一定的参考。 相似文献
152.
皇甫川流域降水和人类活动对水沙变化的定量分析 总被引:4,自引:0,他引:4
采用线性趋势法、非参数Mann-Kendall趋势检验法、累积距平法及径流历时曲线法分析皇甫川流域1955-2010年水沙变化特征,通过水文分析法定量评价降水和人类活动对水沙变化的贡献率.结果表明:皇甫川流域径流量和输沙量均呈急剧减少趋势,尤其在20世纪80年代之后,减少更加显著,近10年(2000-2010)的平均径流量与输沙量相当于1950-1959年的约20%;皇甫站径流量和输沙量均在1979年发生突变;在变化期1980-2010年,人类活动对流域水沙变化的贡献占主导因素,约为70%,而降水所占比例为30%左右;自20世纪80年代始,大规模的水土保持措施(如退耕还林(草)、梯田建设、水库淤地坝等工程)等人类活动是流域水沙锐减的主要影响因素. 相似文献
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为揭示陕西省丹汉江流域典型县土壤侵蚀的空间分布特征,利用地理信息系统技术,通过对石泉县和商南县土壤侵蚀强度分布图和DEM图的叠加,得到土壤侵蚀强度在坡度、坡向、高程、起伏度等地貌因子的空间分布状况。结果表明:研究区水土流失程度较高,土壤侵蚀强度以轻度和中度为主。不同坡度、高程、起伏度下的水土流失面积比例、土壤侵蚀综合指数和土壤侵蚀强度均呈现单峰分布,平地的水土流失面积接近0,不同坡向的土壤侵蚀强度分布差异不显著。不同土壤侵蚀强度的最大值随着坡度升高而增大,但却随着高程的升高而减小。各土壤侵蚀强度的起伏度分布特征均很相似。此结论可为陕西省丹汉江流域中游地区水土保持规划和水土流失治理提供决策依据和理论支持。 相似文献
156.
《Journal of Sustainable Forestry》2013,32(1-2):99-118
Abstract The management of forest ecosystems for sustainabil-ity requires knowledge of the abundance and distribution of all resources, including wood and wildlife, and the ability to predict the impact of management on these resources. Spatially explicit inventories for wildlife are lacking for the vast majority of species. We propose, with example, a method of rapid habitat assessment which can be conducted with available data to produce a spatially explicit inventory of habitat for a species. Information from the literature and some census data were used to construct a simple model of potential habitat for a boreal forest songbird. Available spatial data, including landcover from Landsat TM data, and a digital elevation model, were used to map the distribution of key habitat characteristics onto the landscape. We argue for the development of these preliminary wildlife habitat models using habitat characteristics that are map-pable with currently available remotely sensed data. Given the current trend toward the development of large scale databases of topography and extant land cover, spatially explicit potential habitat models can be efficiently and inexpensively developed to provide a framework for incorporating wildlife habitat into forest management. The relationships between rapid habitat assessment, long-term studies, monitoring, and population viability analysis are discussed. 相似文献
157.
《Journal of Sustainable Forestry》2013,32(1-2):75-97
Abstract Forest pricing policies for tropical timber and forest concessions can play an important role in the management, conservation, and preservation of tropical forests. The paper draws on regional studies of forest revenue systems and forest concession arrangements, country case studies, and studies in individual countries of West and Central Africa and South East Asia (Grut, Gray, and Egli, 1991; Gray and Hadi, 1989; Gray and Hadi, 1990; and Gray, 1983). Forest pricing and concession management policies, problems, and experiences in individual countries are examined, common problems and experiences highlighted, and alternatives identified. From these, the elements of a forest pricing and concession management system which supports sustainable management, efficient utilization, and forest renewal are developed. 相似文献
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159.
《国际水土保持研究(英文)》2019,7(2):138-149
The evaluation of scale effects on modeling performance of sedimentgraphs as the ultimate outputs of the hydrological simulation is vital for adaptive watershed management. The present study therefore analyzed effectability of simulated sedimentgraphs components in association with different topographic maps with various vector scales. The whole procedure was materialized to select the critical scale and cell size for the Galazchai Watershed, Iran. To this end, the stormwise sedimentgraphs were modeled for 23 recorded events using the Clark's Instantaneous Unit Hydrograph (IUH) model stemmed for developing Instantaneous Unit Sedimentgraphs (IUSGs) incorporated with dimensionless sediment concentration distribution (DSCD) based on the vector scales of 1:25000, 1:50000, 1:100000 and 1:250000 and cell sizes of 5, 10, 20 30, 50, 100 and 200 m. Some 644 direct sedimentgraphs (DSGs) were then evaluated based on Relative Errors (REs) for sediment volume, peak sediment, time to peak, base time and the Coefficient of Efficiency (CE). The results confirmed that REs for peak sediment, time to peak and CE were sensitive to cell size. The results further verified that the cell sizes of 5, 20, 30, 50 and 100 m were critical cell sizes in viewpoint of time to peak. In addition, the vector scales of 1:50000 with cell size of 50 m, and 1:100000 with cell sizes of 5 and 10 m were critical vector scales and cell sizes based on RMSE evaluation criterion. It is concluded from the current research that the accuracy of simulation of sedimentgraph was influenced by map scales and mesh sizes. 相似文献
160.