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Nanjing University of Information Science and Technology (2021)

Observational Experimental Study of Land Surface Process in Semi-arid and Rainfed Agriculture Region

杨兴国

Titre : Observational Experimental Study of Land Surface Process in Semi-arid and Rainfed Agriculture Region

Auteur : 杨兴国

Grade : Master 2021

Université : Nanjing University of Information Science and Technology

Résumé partiel
The characteristic of surface radiation, energy balance,albedo,bulk momentum transfer coefficient CD and bulk sensible heat transfer coefficient CH between surface and atmosphere over rainfed field are analyzed based on the data of land-surface process field experiment in the Dingxi arid meteorology and ecological environment experimental station.The maximum of instantaneous global radiation is beyond 1000W/m2 and the ten-days average intensity is 338.90W/m2 because of high atmospheric transparency over semi-arid rainfed agriculture region of loess plateau between June and August.Global radiation, reflected global radiation and surface long wave radiation emerge the characteristic of daily variations on a typical clear day and cloudy day, whereas atmospheric long wave radiation has not this characteristic.Meanwhile,net radiation, latent heat flux sensible heat flux and soil heat flux appear the same characteristic as the mean daily variations above spring wheat field and bare soil on a typical clear day and cloudy day. Moreover, evapotranspiration consumes mainly net radiation on a clear day and sensible heat flux is greater than latent heat flux on a cloudy day above spring wheat field. Soil heat flux from atmosphere to soil is about 5% of net radiation on a clear and cloudy day and soil discharge energy to atmosphere on a rainy day above the same field. In brief, average latent heat, sensible heat and soil heat flux is 40%. 50% and 10% of net radiation respectively. On the contrary, the latent heat and sensible heat on a clear day is 60% and 19% of net radiation above bare soil surface. Similarly, the net radiation on a cloudy day is mainly used up evaporation of soil. The integrated value of soil heat flux is negative on a cloudy day andthat shows the soil emits the heat, which is different on a clear day.

Mots clés : semi-arid region ;rainfed agriculture ;land surface process ;observational experiment ;

Présentation (CNKI)

Page publiée le 27 février 2022