Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Accueil du site → Master → Chine → 2020 → Research on the Characteristics and Modeling of Water and Carbon Fluxes in an Arid Farmland Ecosystem in Northwest China

Lanzhou University (2020)

Research on the Characteristics and Modeling of Water and Carbon Fluxes in an Arid Farmland Ecosystem in Northwest China

许洁;

Titre : Research on the Characteristics and Modeling of Water and Carbon Fluxes in an Arid Farmland Ecosystem in Northwest China

Auteur : 许洁;

Grade : Master’s Theses 2020

Université : Lanzhou University

Résumé
With global warming and global water shortage,many researchers and research institutions more focus on the water and carbon cycles in terrestrial ecosystem.Farmland ecosystem is the closest with human activities across all the ecosystems.It not only promotes the development of social economy,but also affects the atmospheric water and carbon cycles.It is of great significance to quantify the characteristics of water and carbon cycles in farmland ecosystem,which can promote the water resources management and carbon sequestration and emission reduction.In this study,we selected the grape field in the northwest arid area of China,as the research object.We measured meteorological data and water-carbon fluxes between2017 and 2018 from eddy covariance system and soil carbon flux automatic observation system.Based on above observed data,our paper analyzed the characteristics of energy and carbon fluxes,the relationships between water-carbon fluxes and environmental factors,and the law of water-carbon coupling on different time scales.In addition,we evaluated the performance of the simulated water and carbon fluxes by CEVSA model,and predicted the changes of water and carbon in the grape field using CEVSA model in different scenarios.The main conclusions are as follows :(1)From May to October 2017,the energy distribution had obvious daily changes in grape field.The net radiation flux(Rn),sensible heat flux(H),latent heat flux(LE)and soil heat flux(G)increased and then decreased,and the Rn,H and LE reached the maximum at about 14:00.The maximum value of G appeared after 14:00.Energy fluxes changes are different in the growth season from 2017 to 2018.The chenges of Rn and LE are the biggest,and the trends of change are single peak.However,the change of H is opposite to that of LE.When LE is the largest in thegrowing season,H is negative,which is related to the transformation of net radiation flux among the components.(2)The daily trend of net ecosystem exchange(NEE)and gross primary productivity(GPP)in grape fields is basically the same.At night,there was no photosynthesis and low carbon sequestration.The grape field showed weak carbon source.After sunrise,the temperature and light increased,subsequently the photosynthetic capacity increased,which results in strong sink in grape field.The daily variation of carbon fluxes in different months shows obvious seasonal characteristics.

Mots clés : grape filed; Eddy covariance technique; water and CO2 fluxes; CEVSA model;

Présentation (CNKI)

Page publiée le 18 octobre 2020