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高寒地区日光温室地温变化及预报 总被引：2，自引：0，他引：2
利用2012年4月至2013年3月青海大通县日光温室内外地温、气温资料和大通县气象站人工观测资料,分析了高寒冷凉地区不同天气类型下日光温室地温变化规律。结果表明;研究区日光温室内日地温呈正弦曲线变化,晴天变化幅度最明显,阴天最小,地温变幅为地表〉5 cm〉10 cm〉15cm〉20 cm;室内地表、10 cm和20 cm平均地温月变化呈波形变化,最大值出现在7月,最小值在12月;随着深度增加,平均地温年较差逐渐减小;晴天、多云天、阴天不同深度地温平均日较差分别为9.6、8.3、6.1℃;地温日垂直变化仅在14时随着深度增加逐渐下降;除晴天室内最高温度外,其余温度要素与地温之间存在极显著正相关关系;建立的日光温室内10 cm最低温度预报方程和地表最低温度预报模型,可以在业务服务中应用。 相似文献
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扎木曲多金属矿位于唐古拉山北坡,长江源头的沱沱河一带。1/20万地球化学测量在该区圈定AS4甲1HgCu综合异常一处,对该综合异常作1/5万水系沉积物加密测量,将其分解为AS4-1~AS4-5五个子异常,进一步浓缩了找矿靶区。对分解后的重点子异常AS4-3采用土壤测量控制异常浓集中心部位,圈定了一条土壤元素组合异常带,异常重现性好,面积大,元素含量值显著提高。通过对土壤异常带作工程验证并圈出铅矿体9条。为此,地球化学勘查在本区寻找多金属矿是行之有效的,这为在唐古拉山地区寻找多金属矿产提供参考。 相似文献
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在大型工程的变形监测中,传统方法是利用全站仪,按照等级测量规范进行方向法、全圆法观测,测站至少需要1个观测员、1个记录员,每个测回需要人工计算和比较,内业需要后处理,费工、费时、容易出错。结合测绘实践的现实需要,利用VB语言和TCA2003全站仪的内置程序功能,开发变形监测数据自动检查程序,为自动化测绘探索新的方法。 相似文献
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Better understanding of plant community structure in relationship to land use history and nitrogen (N) will facilitate grassland conservation and projections of community succession under future N deposition. We conducted a field experiment in northern China to examine the influence of 2-year N addition on species composition and community structure in three temperate grasslands with different land use history: steppe fenced for two years (ST), steppe fenced for five years (SF), and old field grassland fenced for five years (OF). The results showed previous farming reduced species diversity and plant cover, which is mainly caused by decrease in perennial grasses (PG) and forbs (PF). Nitrogen addition increased plant cover, especially the PG cover, but had little effects on species diversity. Nitrogen enrichment also has a tendency to alter community composition by decreasing proportional cover of PF but increasing that of PG and annuals and biennials (AB), suggesting enhanced dominance of PG under increasing N deposition. Irrespective of the short-term (2 years) experimental periods, our findings highlight the dominant role of land use history in structuring plant community, and have valuable implications for grassland conservation and model projections of ecosystem succession under global scenarios of N deposition in the semi-arid grasslands. 相似文献
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Many sensors have their bands overlapped and therefore do not set a normal space. If a spectral distance is measured, as in first-order statistical classifiers, the direct consequence is that the result will not be the most accurate. Image classification processes are independent of the spectral response function of the sensor, so this overlap is usually ignored during image processing. This paper presents a methodology that introduces the spectral response function of sensors into the classification process to increase its accuracy. This process takes place in two steps: first, incident energy values of the sensors are reconstructed; second, the energy of the bands is set in an orthonormal space using a matrix singular value decomposition. Sensors with and without overlapping spectral bands were simulated to evaluate the reconstruction of energy values. The whole process was implemented on three types of images with medium, high and very high spatial resolution obtained with the sensors ASTER, IKONOS and DMC camera, respectively. These images were classified by ISODATA and minimum distance algorithms. The ISODATA classifier showed well-defined features in the processed images, while the results were less clear in the original images. At the same time, the minimum distance classifier showed that overall accuracy of the processed images increased as the maximum tolerance distance decreased compared to the original images. 相似文献
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青海牧区近10年牧草产量变化与气象条件的关系 总被引：2，自引：0，他引：2
利用DPS统计中的相关、回归等方法分析近10年青海高原牧区5站点牧草产量变化与气象因子的关系,并建立了牧草产量的气象条件多元回归拟合模型。结果表明：近10年来牧草产量的年最高值河南、甘德总体呈下降趋势,曲麻莱、海北、兴海总体呈上升趋势;5站点牧草产量5月变幅最大为兴海,变幅最小的为海北,6—8月变幅最大的是曲麻莱,变幅最小的是海北;5站点8月牧草产量形成期总体上日照充足,降水除河南阶段性较充沛外,其余受限制,温度除河南在牧草生长季内当光温出现匹配不当时呈负相关外,其余均受限制;气象因子与5站点年最高牧草产量的拟合模式拟合效果较好,均可通过0.01检验。 相似文献
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概率积分法是预测煤矿采空区产生地面移动最直接,最简单的方法之一,应用广泛。但该方法的应用条件非常苛刻,对于地层复杂的地区,预测精度不高。本文为预测出多煤组开采造成的地面破坏,将概率积分法与空间分析软件相结合,运用GMS软件的空间分析功能和概率积分法的理论基础,对采空区产生的地面破坏进行预测。将这种方法运用到塔妥煤矿中,得到了当该煤矿的四个煤组完全开采时产生的地面破坏预测,其计算结果比直接运用概率积分法更加接近实际。 相似文献
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利用西宁市1954-2017年降水分钟数据建立暴雨统计样本,采用年最大值法推算暴雨强度公式并推求西宁市短历时暴雨雨型。结果表明：西宁市短历时暴雨雨型单峰特征比较明显,单峰峰值出现在前1/3。历时120 min芝加哥设计雨型综合雨峰位置系数0.27,雨峰位置在35 min左右,峰值前（后）雨强迅速增加（减小）,最大1 h降水量为13.14 mm,降水主要集中在20～80 min。各历时的瞬时雨强变化趋势以及分布型基本一致,雨强随着重现期的增大而增大。累计降雨雨峰前（后）增长斜率升（降）最大。西宁市暴雨分布呈现局地性强,空间差异明显特征,芝加哥设计雨型结果对城西和城北区代表性较好,城中和城东区可参考使用。 相似文献
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A review of formation mechanism and restoration measures of “black-soil-type” degraded grassland in the Qinghai-Tibetan Plateau 总被引：2，自引：0，他引：2
Quan-Min Dong Xin-Quan Zhao Gao-Lin Wu Jian-Jun Shi Guo-Hua Ren 《Environmental Earth Sciences》2013,70(5):2359-2370
The aim of this paper was to review the formation mechanism and restorative measures of the black-soil-type degraded grassland ecosystem of the source area of Yangtze and Yellow Rivers, Qinghai-Tibetan Plateau. The relationship among plants, animals, soil, climate change, human activity and the black-soil-type degraded grassland was analyzed based on a review of literature and report of previous investigations conducted by the authors. Degradation of the black-soil-type grassland was caused by a set of complex factors such as altitude range, district characteristics and weather conditions, which existed for a long period of time. Livestock overgrazing and climate dryness were the dominant factors that caused the degradation of the grassland in question. In addition, damages done by rodents, especially pikas (Ochotona curzoniae), via burrowing through the turf and gnawing at herbs have sped up the formation process of the degradation of the black-soil-type grassland. Furthermore, with the inflation of the population in the last 20 years, the influence of human activity on grassland degradation cannot be neglected. Based on the different successive stages of degradation of the black-soil-type grassland ecosystem, different restorative measures were suggested. The lightly and moderately degraded grasslands should be kept away from disturbance, such as fencing closure, weeding, fertilizing, using rodenticide, decreasing stocking rate, optimizing population structure stocked and slaughter ages; whereas the artificial and semi-artificial grassland establishment required to restore ecosystems should be applied to heavily and extremely degraded grasslands. 相似文献