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

Titre : Simulation and Optimization of Net Primary Productivity in Arid Area of Northwest China ——A Case Study of Jiuquan City

Auteur : 张璐

Grade : Master 2022

Université : Lanzhou University

Résumé partiel
With the development of technology and productivity,the impact of human activities on the ecosystem has been gradually enhanced,causing environmental problems such as global warming.To deal with climate change,many countries have signed the United Nations Framework Convention on Climate Change,the Kyoto Protocol and the Paris Agreement.China has announced that it will strive to peak carbon dioxide emissions by 2030 and achieve carbon neutrality by 2060.As an important measure to achieve the carbon peaking and carbon neutrality goals,"increasing the sink" is mainly to enhance the natural carbon sequestration capacity of the ecosystem by improving the level of vegetation coverage.Net primary productivity（NPP）is an important indicator of terrestrial ecosystem carbon sequestration ability.The research of NPP space-time distribution and variation characteristics,analysis of the influence of different factors on NPP change and forecast development trend of NPP is of great significance for evaluating regional ecological base,ascertaining regional ecological potential and making decisions more scientific.The arid area in northwest China is an important ecological function area.The terrestrial ecosystem is extremely fragile and difficult to recover after being damaged,which affects its carbon sequestration ability and regional carbon balance.In the past,the spatial distribution of NPP was mainly discussed,but the influencing factors and optimal prediction of NPP were seldom studied.Taking Jiuquan as the research area,this thesis calculated the NPP value of Jiuquan from 2000 to 2019 by CASA model,and analyzed its distribution characteristics and spatio-temporal variation trend.Secondly,based on the Thornthwaite Memorial model and residual method,the potential net primary productivity（PNPP）and the impact of human factors on NPP（HNPP）in Jiuquan were calculated,and the relative impact of climate and human factors on NPP in different regions was quantitatively compared.Finally,based on the analysis and simulation of land use change characteristics,the total NPP and economic benefits of Jiuquan in 2030 under different scenarios are calculated,which has certain reference value for improving the potential of carbon sink in the arid area of northwest China.This thesis mainly draws the following conclusions:1.Distribution characteristics and changing trend of net primary productivity in Jiuquan:The average value of NPP in Jiuquan is low,and for the overall characteristics,NPP in the central region is high while low in the southern and northern region.The area of high NPP increased significantly from 2000 to 2019,and the NPP of different types of land varied greatly and fluctuated with time.The distribution of NPP differed significantly in different seasons.NPP increased slowly in most regions,with a significant increase in the south and a downward trend in the north.The regional distribution was uneven and varied greatly.2.Evaluation of the relative impact of climate and human factors on NPP in Jiuquan:PNPP maintained positive growth in all regions,and the high value mainly appeared in the southern Qilian mountains,while the low value mainly appeared in the western desert.T

Mots clés : Arid Area of Northwest China ;Net Primary Productivity ;CASA Model ;Influencing Factors ;GMOP-PLUS Coupling Model ;

Présentation (CNKI)