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Ludong University (2019)

Temporal and Spatial Variation Characteristics of Wind Speed and Its Influence on Wind Erosion Climatic Erosivity in the Wind Erosion Region of Northern China

韩柳;

Titre : Temporal and Spatial Variation Characteristics of Wind Speed and Its Influence on Wind Erosion Climatic Erosivity in the Wind Erosion Region of Northern China

Auteur : 韩柳;

Grade : Master’s Theses 2019

Université : Ludong University

Résumé partiel
The wind erosion in the wind erosion area in northern China is serious,the Gobi desert is widespread,and the dust source is extremely rich.Wind as a driving force for soil wind erosion plays a vital role in the occurrence and movement of soil wind erosion.In this study,the observation data of 186 ground meteorological observatories in the northern wind erosion area from 1970 to 2017 were used to analyze the spatial and multivariate time scale changes of the average wind speed in the region using methods such as climatic erosivity,spatial interpolation,bfast mutation analysis and wavelet analysis.Characteristics and trends,periodic characteristics and abrupt changes ;statistics of different levels of wind speed days,analysis of temporal and spatial characteristics of wind speed days of each level,and temporal and spatial correlation between different levels of wind speed days and average wind speed ;using wind erosion climatic factor index to calculate wind erosion climate in the region Erosion,analyze the temporal and spatial distribution and variation characteristics of wind erosion climatic erosivity,and use the methods of time-space correlation and sensitivity analysis to focus on the driving force analysis of wind erosion climatic force in wind erosion area in northern China.The main conclusions are as follows :(1)During the period from 1970 to 2017,the average annual wind speed in the wind erosion area of northern China was 2.66 m/s,showing a significant downward trend,and the rate of decline was 0.016 m/(s·a).There were significant differences in wind speed variations in different seasons.The annual average wind speed tendency rate in the northern wind erosion area ranges from-0.084 to 0.104 m/(s·a),and there is a spatial difference in wind speed variation.In the north wind erosion area,northwestern and southeastern Xinjiang,Qinghai,central Inner Mongolia and northeastern part Heilongjiang and Jilin are the regions with faster wind speed reduction.The southeastern part of Gansu,Ningxia,Shanxi and northwestern Shaanxi,Liaoning,Xinjiang,and the northwestern part of Xinjiang are areas where wind speed is not significantly reduced.There are multiple time-scale periodic structures of wind speed change.Characteristics,the 28-year time scale is the main period of the wind speed period change,and the average change period is 19 years ;the BFAST algorithm deals with the monthly average wind speed in the northern wind erosion area.The results show that there are two sudden changes in the trend component,and the time nodes are 1988.Month and March 2011.(2)The number of wind speed days in grade I(0-5 m/s)of wind erosion area in northern China shows an increasing trend.The grades of wind speed II(5-10 m/s)and III grade(above 10 m/s)show a decreasing trend.The trend of the four seasons is consistent with the annual trend,and the rate of change is significantly different between the four seasons ;the spatial distribution of the number of wind speed days of the I grade has a good high and low correspondence with the grade II and III ;in the past 48 years,with the wind speed grade

Mots clés : the wind erosion region of Northern China; wind speed; wind erosion climatic erosivity; spatial and temporal characteristics;

Présentation (CNKI)

Page publiée le 28 avril 2020