錫林郭勒典型草原區(qū)積雪過程與風(fēng)雪流研究
發(fā)布時間：2018-11-17 17:54
【摘要】：錫林郭勒草原是溫帶草原最為典型的代表,是我國重要的牧業(yè)生產(chǎn)基地,同時也是我國北疆重要的生態(tài)屏障。研究區(qū)地處我國三大積雪高值區(qū)之一,積雪資源豐富,是重要的季節(jié)性積雪區(qū)。漫長嚴(yán)寒的冬季,加上強勁的風(fēng)力條件,積雪災(zāi)害頻發(fā),嚴(yán)重阻礙了地區(qū)經(jīng)濟的發(fā)展。本文在對典型草原地區(qū)風(fēng)雪環(huán)境氣象因子動態(tài)分析和積雪時間尺度分析基礎(chǔ)上,通過對積雪過程及風(fēng)雪流的野外觀測,分析了不同時期積雪的密實化過程,不同環(huán)境及積雪條件下的風(fēng)雪流運行情況,以及風(fēng)雪流二次積雪分布規(guī)律,主要研究結(jié)果如下:1.錫林浩特45a降雪量和積雪日數(shù)沒有明顯的突變點,而積雪深度在2000年和2003年發(fā)生了兩次有少到多的突變;降雪量、積雪日數(shù)和積雪深度三個積雪因子的主周期均為11a;降雪量、濕度、蒸發(fā)量和風(fēng)速對吹雪的發(fā)生日數(shù)影響較大,通過BP神經(jīng)網(wǎng)絡(luò)模型的預(yù)測,吹雪發(fā)生日數(shù)呈減少趨勢。2.穩(wěn)定積雪期內(nèi),依據(jù)具有顯著階段變化特征的積雪深度對積雪密實化過程劃分,可分為積雪密實化劇烈變化期(前24h)、快速變化期(24h—48h)和穩(wěn)步發(fā)展期(48h之后)三個階段;不穩(wěn)定積雪期內(nèi),積雪深度與積雪密度均沒有明顯的分段變化特征,且整個密實化過程明顯快于穩(wěn)定積雪期。積雪密度隨沉積時間逐漸增大。3.大針茅平坦草地在多風(fēng)速梯度作用下,近地表100cm范圍風(fēng)雪流表現(xiàn)為移雪強度、移雪量百分比均隨距離雪面高度增加而急劇減弱。隨著2m處風(fēng)速的增加,相同高度處移雪強度增強,風(fēng)雪流結(jié)構(gòu)函數(shù)發(fā)生從對數(shù)函數(shù)到冪函數(shù)的轉(zhuǎn)變。移雪量主要集中在近地表20cm范圍內(nèi),占到總移雪量的80%以上;平均移雪強度與2m高度處風(fēng)速呈極顯著(P0.001)的冪函數(shù)關(guān)系,關(guān)系式為Q=a·Vb形式,冪指數(shù)約為5,隨風(fēng)速增加平均移雪強度發(fā)生從緩慢增加到急劇增強的變化過程。4.積雪面出露的植被、積雪沉積時間、積雪深度、地形條件等環(huán)境或積雪本身均對風(fēng)雪流的運行存在不同程度的影響。移雪強度、單寬輸雪率等指標(biāo)隨著出露植被高度、出露植被蓋度的增加而顯著減弱,積雪沉積越久形成風(fēng)雪流強度越弱;由于地形對風(fēng)速廓線的影響,迎風(fēng)側(cè)的風(fēng)雪流運行的高度和強度明顯強于背風(fēng)坡,在坡中位置表現(xiàn)的最為顯著。5.大針茅平坦草地積雪深度隨植被高度呈線性關(guān)系增長,相關(guān)性強弱表現(xiàn)為放牧打草封育。積雪深度隨植被蓋度呈對數(shù)函數(shù)增加,當(dāng)植被蓋度增加到一定程度后積雪深度增加趨于緩慢;大針茅平坦草地內(nèi)積雪深度在降雪量豐富年份沉積的更多,而且在利用程度輕的草地內(nèi)表現(xiàn)的更加明顯。
[Abstract]:Xilingol prairie is the most typical representative of temperate grassland, an important animal husbandry production base in China, and also an important ecological barrier in northern Xinjiang. The study area is located in one of the three high value snow cover areas in China, which is rich in snow resources and is an important seasonal snow cover area. The long cold winter and the strong wind condition, the frequent snow disaster seriously hindered the development of the regional economy. Based on the dynamic analysis of snow and snow environmental meteorological factors and the analysis of snow cover time scale in typical grassland area, this paper analyzes the snow densification process in different periods through the field observation of snow cover process and snowstorm flow. The operation of snow flow and the distribution of secondary snow cover under different environment and snow cover conditions. The main results are as follows: 1. In Xilinhaote, there were no significant abrupt changes in snow amount and snow days in 45a, but there were two abrupt changes in snow depth in 2000 and 2003. The main periods of snow fall, snow days and snow depth were 11a. Snowfall, humidity, evaporation and wind speed have great influence on the number of snow blowing days, and the number of snow blowing days is decreasing through the prediction of BP neural network model. 2. In the stable snow cover period, the snow compaction process can be divided into two periods according to the snow depth, which has the characteristic of significant phase change, which can be divided into two periods (the first 24 hours). Rapid change period (24h-48h) and steady development stage (after 48 hours); During the unstable snow cover period, the snow depth and the snow density have no obvious variation characteristics, and the whole compaction process is obviously faster than that of the stable snow cover period. The density of snow increased with the deposition time. Under the action of multiple wind speed gradient, the snowdrift intensity in the 100cm range near the surface was observed, and the percentage of snow moving decreased sharply with the increase of the height of snow surface. With the increase of wind speed at 2m, the intensity of snow moving at the same height increases, and the structural function of snow flow changes from logarithmic function to power function. The amount of snow moving is mainly concentrated in the range of 20cm near the surface, accounting for more than 80% of the total amount of snow moving. The relationship between the average snow moving intensity and the wind speed at 2m height is very significant (P0. 001). The relation is Qa Vb form, and the power exponent is about 5. With the increase of the wind speed, the average snow moving intensity changes from slow to sharp. 4. The vegetation, deposition time, snow depth, topographic conditions and snow cover have different effects on the flow of snow. The intensity of snow movement and the rate of single wide snow transport decreased with the height of exposed vegetation and the coverage of exposed vegetation. The longer the snow deposited, the weaker the snowstorm flow intensity was. Because of the influence of topography on the wind profile, the height and intensity of the windward wind flow is obviously stronger than that of the leeward slope, and the position in the slope is the most obvious. The depth of snow cover increased linearly with the height of vegetation, and the correlation was shown as grazing and forage fencing. The snow cover depth increases with the vegetation coverage as a logarithmic function, and when the vegetation coverage increases to a certain extent, the snow cover depth increases slowly. The depth of snow in the flat grassland is more than that in the year of rich snowfall, and it is more obvious in the grassland with light utilization.
【學(xué)位授予單位】：內(nèi)蒙古農(nóng)業(yè)大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2017
【分類號】：S812
本文編號：2338623
[Abstract]:Xilingol prairie is the most typical representative of temperate grassland, an important animal husbandry production base in China, and also an important ecological barrier in northern Xinjiang. The study area is located in one of the three high value snow cover areas in China, which is rich in snow resources and is an important seasonal snow cover area. The long cold winter and the strong wind condition, the frequent snow disaster seriously hindered the development of the regional economy. Based on the dynamic analysis of snow and snow environmental meteorological factors and the analysis of snow cover time scale in typical grassland area, this paper analyzes the snow densification process in different periods through the field observation of snow cover process and snowstorm flow. The operation of snow flow and the distribution of secondary snow cover under different environment and snow cover conditions. The main results are as follows: 1. In Xilinhaote, there were no significant abrupt changes in snow amount and snow days in 45a, but there were two abrupt changes in snow depth in 2000 and 2003. The main periods of snow fall, snow days and snow depth were 11a. Snowfall, humidity, evaporation and wind speed have great influence on the number of snow blowing days, and the number of snow blowing days is decreasing through the prediction of BP neural network model. 2. In the stable snow cover period, the snow compaction process can be divided into two periods according to the snow depth, which has the characteristic of significant phase change, which can be divided into two periods (the first 24 hours). Rapid change period (24h-48h) and steady development stage (after 48 hours); During the unstable snow cover period, the snow depth and the snow density have no obvious variation characteristics, and the whole compaction process is obviously faster than that of the stable snow cover period. The density of snow increased with the deposition time. Under the action of multiple wind speed gradient, the snowdrift intensity in the 100cm range near the surface was observed, and the percentage of snow moving decreased sharply with the increase of the height of snow surface. With the increase of wind speed at 2m, the intensity of snow moving at the same height increases, and the structural function of snow flow changes from logarithmic function to power function. The amount of snow moving is mainly concentrated in the range of 20cm near the surface, accounting for more than 80% of the total amount of snow moving. The relationship between the average snow moving intensity and the wind speed at 2m height is very significant (P0. 001). The relation is Qa Vb form, and the power exponent is about 5. With the increase of the wind speed, the average snow moving intensity changes from slow to sharp. 4. The vegetation, deposition time, snow depth, topographic conditions and snow cover have different effects on the flow of snow. The intensity of snow movement and the rate of single wide snow transport decreased with the height of exposed vegetation and the coverage of exposed vegetation. The longer the snow deposited, the weaker the snowstorm flow intensity was. Because of the influence of topography on the wind profile, the height and intensity of the windward wind flow is obviously stronger than that of the leeward slope, and the position in the slope is the most obvious. The depth of snow cover increased linearly with the height of vegetation, and the correlation was shown as grazing and forage fencing. The snow cover depth increases with the vegetation coverage as a logarithmic function, and when the vegetation coverage increases to a certain extent, the snow cover depth increases slowly. The depth of snow in the flat grassland is more than that in the year of rich snowfall, and it is more obvious in the grassland with light utilization.
【學(xué)位授予單位】：內(nèi)蒙古農(nóng)業(yè)大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2017
【分類號】：S812
【相似文獻(xiàn)】
相關(guān)重要報紙文章 前2條
1 記者 李鐵;我國科學(xué)家成功解決天山“風(fēng)雪流”治理難題[N];光明日報;2002年
2 本報記者 潘繼鵬 通訊員 黃新 林刁平;從瑪依塔斯風(fēng)雪流說起[N];中國氣象報;2013年
相關(guān)博士學(xué)位論文 前1條
1 劉寶河;錫林郭勒典型草原區(qū)積雪過程與風(fēng)雪流研究[D];內(nèi)蒙古農(nóng)業(yè)大學(xué);2017年
相關(guān)碩士學(xué)位論文 前4條
1 桑嘉賓;混合粒徑風(fēng)雪流運動的數(shù)值模擬[D];蘭州大學(xué);2012年
2 王仁可;微地表形態(tài)下風(fēng)雪流運動的數(shù)值模擬[D];蘭州大學(xué);2014年
3 韓凱;雪粒形狀對風(fēng)雪流發(fā)展過程影響的數(shù)值模擬研究[D];蘭州大學(xué);2010年
4 張潔;平坦床面上風(fēng)雪流運動的力學(xué)機理分析[D];蘭州大學(xué);2008年
，本文編號：2338623
本文鏈接：http://sikaile.net/shoufeilunwen/nykjbs/2338623.html
最近更新
教材專著
