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Inner Mongolia Agricultural University (2017)

Evapotranspiration Variation and Model Simulation in Cascade Ecosystem in Horqin Sandy Land

王丹;

Titre : Evapotranspiration Variation and Model Simulation in Cascade Ecosystem in Horqin Sandy Land

Auteur : 王丹;

Grade : Master’s Theses 2017

Université : Inner Mongolia Agricultural University

Résumé
Based on the observation data at July on mobile dune in Horqin sandy,the paper compares Double rotation,sensible and latent heat flux which corrected through Planar fit,date quality-the turbulence characteristics.Select cascade a Horqin sandy land ecosystem,combining with evapotranspiration measured by eddy covariance in 2015、2016,using Shuttleworth-Wallace(S-W)model of the ecological system,to simulate the evaporation and suitability assessment.Conclusions are drawn as follows :(1)Gentle topography area(180°-300°),w>0,β is around 1.677 3 ° ;steep topography area(330 °-180 °),w<0,β is around-1.648 6 °.LE which corrected by DR increases 17% ;After correcting by PF,LE reduces 15%.The data after corrected by DR and PF are separately 89.6%、89.3%through the test the adequacy of the development of turbulence.Wind friction velocity corrected by DR has higher relativity than before corrected ;The surface energy closure rate increase 3.47%after being corrected by DR and increases 2.78%after being corrected by PF.Throughout the growing season,6、8month after the reduction of vorticity have better impove data quality.So the performance of the DR is better than the PF.(2)In addition to the A4 station,the ecosystem in a typical sunny day evaporation shows obvious bell-shaped distribution,and as the change of season,evaporation of increase and decrease respectively by 6:00 until 7:00,advance by 19:00 to 18:00."Noon break" phenomenon,due to vegetation BC4 evaporation,C4、G4 station between 11:30-13:00 will be reduced,evaporation and G4 station reduction is obviously higher than BC4、C4.Whole corn BC4 above meadow C4,higher than that of fixed sand dunes F4,semi-fixed dunes G4,mobile dune A4 minimun ;Rainfall in each ecosystem influence degree is different,influence on A4 is minimized,the biggest influence on C4 ;The most significant affect the ecosystem evaporation meteorological factors is Rn,not significant factor is the 0.(3)Day scale,S-W model in BC4 high applicability,A4 is minimum ;Day scale simulation accuracy is lower than the hour scale ;Hours scales,evaporation simulation accuracy influenced by the weather,sunny days than cloudy and rainy days,the ecosystem suitability from high to low is:BC4,C4,G4,A4,F4 ;S-W model maximum resistance and meteorological parameters are respectively Rn and LAI,and 0 is the smallest respectively ;Resistance and meteorological parameters influence the biggest ecosystem were C4 and F4,the smallest G4 and C4.To sum up,S-W model of corn in Horqin sandy land and the applicability of the meadow to better.

Mots clés : Horqin sandy land; Stair ecological ecosystem; Eddy covariance; Coordinate rotation method; Evaporation; S-W model; Suitability analysis model; Parameter sensitivity analysis;

Présentation (CNKI)

Page publiée le 2 février 2018