不同监测技术和计算方法对降雨动能指标精确度的影响

发布时间：2018-05-11 21:00

本文选题：降雨量 + 降雨动能　；参考：《长江科学院》2017年硕士论文

【摘要】：我国是世界上水土流失最严重的国家之一,土壤侵蚀是导致土地资源退化乃至彻底破坏的主要原因。雨滴击溅和降雨产生的径流,是土壤侵蚀的主要动力,因此对侵蚀动力的研究是准确预报水土流失的基础和前提。一般情况下采用降雨侵蚀力指标来估算一定时期内侵蚀性降雨的侵蚀动力,由于难获得所必须的降雨动能指标,因此一般采用降雨侵蚀力简易算法,即利用雨量站等常规降雨统计资料如日雨量、月雨量、年雨量或其它雨量参数来估算侵蚀力。目前,随着高新监测降雨设备发展,给降雨动能及降雨侵蚀力的获取带来了方便,同时也为土壤侵蚀动力的理论研究带来了新的机遇和挑战。在湖北省武汉市布设自动雨量计(简称AR)、自动气象站(简称AM)和2DVD视频雨滴谱系统(简称2DVD)降雨监测仪器,选择它们同期监测的降雨数据作为研究对象,分析比较了3种仪器监测的降雨过程指标对降雨量、降雨强度、降雨动能及降雨侵蚀力等的影响,同时比较8种常用降雨侵蚀力计算公式的精确度,主要结论如下:(1)结合2016-2017年时段内汉口江滩雨量站雨量值,发现布设的降雨监测仪器与汉口汉滩雨量站的降雨量在同一数量级,代表了这些仪器监测得到的降雨数据比较合理;因为3种仪器监测的降雨量与其相比,AR与其相差最小,表明AR对降雨量监测的精确度最高,不得不指出2DVD监测结果偏差较大,这说明该仪器能否监测降雨量还需进一步论证。(2)2DVD能够直接测定雨滴的大小和速度,直接计算出降雨动能Ev。利用其监测到的雨滴直径、速度和降雨强度数据,计算降雨动能Ev和由RUSLE中降雨动能计算公式得到的结果Er相差较小,这也说明该仪器有漏测雨滴或降雨量。同时,直接根据2DVD监测到的雨滴大小和速度计算的降雨动能Ev能够较好地反应视频雨滴谱系统监测的真实情况。(3)选取8个降雨侵蚀力简易公式,其中EI10、EI60、PI10、PI30与经典公式EI30偏差较大。自动雨量计条件下,殷水清和王万忠等(1995)分别建立的简易公式计算的结果与EI30偏差都很小。2DVD条件下,只有殷水清提出的公式对应的结果与EI30偏差较小。(4)分析AR及2DVD监测计算得到的降雨动能与降雨量之间关系,表明直接用降雨量代替降雨动能计算降雨侵蚀力存在一定的缺陷。(5)根据AR与2DVD监测的降雨量之间的对比关系,建立降雨量拟合公式,从而对2DVD监测并计算出降雨动能及降雨侵蚀力进行修正。结果发现降雨动能的修正值较为满意,对降雨侵蚀力的修正有待改进。
[Abstract]:Soil erosion is one of the most serious soil erosion countries in the world. Soil erosion is the main cause of land resources degradation and even total destruction. Runoff caused by raindrop splash and rainfall is the main driving force of soil erosion, so the study of erosion power is the basis and prerequisite for accurate prediction of soil erosion. In general, the rainfall erosivity index is used to estimate the erosive power of erosive rainfall in a certain period of time, because it is difficult to obtain the necessary rainfall kinetic energy index, so the simple algorithm of rainfall erosivity is generally used. That is to say, the erosivity is estimated by the daily rainfall, monthly rainfall, annual rainfall or other rainfall parameters, such as daily rainfall, monthly rainfall, annual rainfall and other rainfall statistics. At present, with the development of high and new rainfall monitoring equipment, it is convenient to obtain rainfall kinetic energy and rainfall erosivity, and it also brings new opportunities and challenges to the theoretical research of soil erosion power. In Wuhan, Hubei Province, automatic Rain Meter (ARA), automatic Weather Station (AMM) and 2DVD Video raindrop Spectrum system (2DVD) rainfall monitoring instruments were installed. The rainfall data monitored by them during the same period was chosen as the research object. The effects of rainfall process indexes monitored by three kinds of instruments on rainfall, rainfall intensity, rainfall kinetic energy and rainfall erosivity are analyzed and compared. At the same time, the accuracy of eight commonly used formulas for calculating rainfall erosivity is compared. The main conclusions are as follows: (1) combined with the rainfall value of Hankou beach rainfall station in 2016-2017, it is found that the rainfall monitoring instrument is of the same order of magnitude as that of Hankou beach rainfall station, which represents the reasonable rainfall data obtained by these instruments. Because the rainfall measured by three kinds of instruments has the smallest difference between AR and rainfall, which indicates that AR has the highest accuracy to rainfall monitoring, it must be pointed out that the deviation of 2DVD monitoring results is large. This indicates that it is necessary to further demonstrate that the instrument can directly measure the size and velocity of raindrops and calculate the rainfall kinetic energy Ev directly. Using the data of raindrop diameter, velocity and rainfall intensity, the difference between the calculated rainfall kinetic energy E _ v and the result obtained from the formula of rainfall kinetic energy in RUSLE is relatively small, which also indicates that the instrument has leakage to measure raindrop or rainfall. At the same time, the rainfall kinetic energy (EV) calculated directly from the size and velocity of raindrops monitored by 2DVD can better reflect the real situation of the video raindrop spectrum system monitoring.) eight simple formulas for rainfall erosivity are selected, in which EI10EI60 PI10PI30 deviates greatly from the classical formula EI30. Under the condition of automatic rain gauge, the calculation result of the simple formula established by Yin Shuiqing and Wang Wanzhong respectively and the deviation of EI30 are very small. Only the result corresponding to the formula proposed by Yin Shuiqing and the smaller deviation of EI30 are used to analyze the relationship between rainfall kinetic energy and rainfall obtained by AR and 2DVD monitoring calculation. The results show that there are some defects in calculating rainfall erosivity with rainfall instead of rainfall kinetic energy. (5) according to the comparative relationship between AR and rainfall monitored by 2DVD, the fitting formula of rainfall is established. Thus, the rainfall kinetic energy and rainfall erosivity are corrected by 2DVD monitoring. The results show that the correction value of rainfall kinetic energy is satisfactory, and the correction of rainfall erosivity needs to be improved.
【学位授予单位】：长江科学院
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S157

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