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Inner Mongolia Agricultural University (2010)

Analysis on Distribution Characteristics of the Reference Crops Evapotranspiration (ET_0) Base on GIS in Inner Mongolia

胡守忠;

Titre : Analysis on Distribution Characteristics of the Reference Crops Evapotranspiration (ET_0) Base on GIS in Inner Mongolia

Auteur : 胡守忠;

Grade : Doctoral Dissertation 2010

Université : Inner Mongolia Agricultural University

Résumé partiel
ET0 is one of the most important parameters for hydrological cycle and determine crop water demand. It was estimated using Penman-Motheith (PM) and FAO24 Penman (FP) approaches based on 135 weather stations distributed all over Inner Mongolia with 30 years observed data (1960-1990). The daily and yearly average ET0 was obtained and did research on the area distribution. The principal factors to influence ET0 in the climate of extreme arid, semiarid and relative humid were analyzed and filtraed.Wavelet theory was employed for scale analysis of ET0 using the data from three stations representing typical climate conditions, which are located at the west, the middle, and the east of Inner Mongolia. As a result of this, the errors of ET0 between PM and FP approaches were corrected based on the 30 years data from these stations.The technology of GIS was used to draw ET0 isogram with 30 years observed data and the distribution characteristics were analyzed by capacity of evaporation and transpiration in Inner Mongolia.To Based on 135 weather stations and 30 years meteorologic data for month-to-month, both the method of PM and FP were applied to caculate the value of ET0、ETrad and ETaero.The results as follow :(1). ET0 calculated by PM is greater than that by FP. The maximum difference is 0.76mm/d with a different rate of 15% and the minimum difference is 0.02mm/d with a different rate of 0.2%.(2). The evapotranspiration in Inner Mongolian area reduced gradually from west to east, the maximum value of ET0 by PM was 7.22mm/d(1148mm/y), that was lake Guaizi located in Ejin Qi at the most west, the minimum value was 2.94mm/d(538mm/y) at the east of Ergun Zuo Qi in the most Northeast area. The evapotranspiration in the mid-west area was big, which suit the characteristic of region climate.(3). The change of ETrad value computed by PM and FP were steady, but the ETaero value varied within wide limits. The sensitivity analysis shown that wind speed and air temperature were the most sensitive parameters for ETaero and ETrad respectively. ETrad and ETaero increased with the decrease of humidity, and vice versa. We chose daily meteorologic data representing typical climate conditions, aquired the value of ET0、ETrad and ETaero by PM and carried key analysis to ET0 and meteorological factors that had influence on the three value :(1). The whole tendency of ET0 value was sorted by Ejin Qi > Hohhot >Ergun Zuo Qi(2). Th change tendency of ETaero and ET0 was basic the same in extreme arid area (Ejin Qi), where the ET0 was mainly influenced by aerodynamic force and the change of ETrad was steady.(3). The range of ET0 falled steadily in the semi-arid region(Huhhot), where the ET0 was mainly influenced by radiation and aerodynamic force. the change scope of ETaero and ETrad was greater.(4). Th change tendency of ETaero and ET0 was basic the same in semi-humid area(Ergun Zuo Qi), where the ET0 was mainly influenced by radiation.The change of ETaero was relative steady ,but the change scope of ETrad was greater.According to wavelet theory for scale analysis of ET0 ,the change of ET0 and its constitutional items—radiation and aerodynamic force were mainly experienced 3 stages from April to September. The change in the 3 areas laged gradually. Moreover, the change of radiation slightly advanced ET0 for each aera, while the change of aerodynamic force laged behind ET0. At the same time, the point of inflection also obeyed the similar rule. In the entire time domain, ET0 and its constitutional items—radiation and aerodynamic force at the 3 areas had relative good corresponding relationship.(1). The change characteristic of ET0、ETrad and ETaero at the three areas : From mid-May to the end of July ET0、ETrad and the ETaero were all greater at west, the ETrad was greater from the beginning of June to the end of August ,which slightly lagged behind the change of ET0 for 10 days. From April, ET0 and its constitutional item—radiation at the middle part experienced 3 stages, namely before May (the few times), to the end of August (many times), to September (few times).

Mots clés : Evapotranspiration; Geographic Information System; isogram; Wavelet theory;

Présentation (CNKI)

Page publiée le 18 mai 2018