| 输沙势计算中的“时距”问题 |
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| 引用本文： | 张正偲,董治宝,赵爱国.输沙势计算中的“时距”问题[J].干旱区地理,2010,33(2). |
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| 作者姓名： | 张正偲 董治宝 赵爱国 |
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| 作者单位： | 中国科学院寒区旱区环境与工程研究所沙漠与沙漠化重点实验室,甘肃,兰州,730000 |
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| 基金项目： | 国家自然科学基金重点项目 |
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| 摘 要： | 风力作用是干旱区风蚀过程和风沙地貌形成发展过程的动力基础,我们在探讨区域的风力作用时,通常是利用风速资料。风速是评价区域风沙活动的基础,但不同方法采集的风速资料对评价结果的影响并不一样。利用野外实测的风速资料进行不同时距处理,旨在说明时距在评价区域风沙作用的影响。结果表明,利用数据中值计算的结果要比平均值大11.31%,这说明以往研究中对输沙势的评价有偏大的现象。但是,由于以往所用数据的时距比较长,又造成计算的输沙势减小的趋势,随着时距增加,数据最大值/峰值降低,数据偏离中值的程度越明显,不论是利用中值还是平均值来计算输沙势,随着时距的增加,计算的DP值逐渐越小。对于用风速平均值计算的DP,1 min的计算结果要比5 min的计算大4.94%,比10 min的计算结果大16.90%,比15 min的计算结果大17.78%;而对于用中值计算的DP,1 min的计算结果要比5 min的计算大4.84%,比10 min的计算结果大16.70%,比15 min的计算结果大17.38%。
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| 关 键 词： | 风速 时距 风沙活动 输沙势 |
Effect of different time intervals in assessing sand drift potential |
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| Abstract: | Wind is the power of wind erosion process and the form of arid zone geomorphology.Wind velocity and direction are the main data to assess regional blown sand disaster;however,different source wind data have differ-ent effect on regional blown sand disaster assessments.In the paper,the real time wind velocity data in the shifting sand region of the Tengger Desert were measured and the original wind velocity was required 1 min.To access the influence of wind velocity on sand drift potential,the original and different time-interval wind velocity data were used.After comparisons,it was found that the longer the wind velocity interval is,the more obvious the deviation from wind mid-point value is,and the larger the maximum wind velocity decreases.At the same time,the relation-ship between wind data of different intervals can be described as linear functions.The total DP(drift potential) calculated by means of the mid-point wind velocity is 11.31% larger than that calculated with the mean wind veloc-ity;as the time-interval increases,the calculated over-estimate value increases.For different time-interval wind ve-locities,regardless of both the mid-point velocity and the mean wind velocity,the longer the time-interval is,the more the calculated DP decreases.For mid-point wind velocity,using 1 min wind velocity to calculate DP,the re-suit is that 1 min's DP value is 4.84%,16.70%and 17.38% larger than that of5 min's,10 min's and 15 min's,respectively.For meatl wind velocity,using 1 min wind velocity to calculate DP,the result is that 1 min's DP value is 4.94%,16.90%and 17.78%larger than that of 5 min's,10 min's and 15 min's,respectively. |
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| Keywords: | wind speed time interval DP |
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