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Lanzhou University (2020)

Warm Island Effect in the Lake Group Area of the Badain Jaran Desert

梁晓燕

Titre : Warm Island Effect in the Lake Group Area of the Badain Jaran Desert

Auteur : 梁晓燕;

Grade : Doctoral Dissertation 2020

Université : Lanzhou University

Résumé
The Badain Jaran Desert has the highest megadune in the world.It is located on the northwestern Alxa Plateau in north-central China.Covering an area of 5.2×10 4 km 2,the Badain Jaran Desert is the second-largest desert in China.It is characterized by the coexistence of more than 110 perennial lakes and thousands of megadunes.Previous studies in this region have primarily been focused on the geochemistry of the groundwater and lakes,past fluctuations in lake level,the eolian geomorphologyand the key problems regarding the source(s)of lake water.The traditional view holds that an oasis or lake in the desert or Gobi is a cold source,namely,the cold island effect.As a unique region with more than 110 lakes,it is founded that the temperature in the lake group region of the Badain Jaran Desert was significantly higher than that in other regions of the deserts by using the field observation data and remote sensing and geographic information system technology(i.e.,a“warm island effect”).However,as the research on the warm island effect is still in its starting stage,its stability and reliability need to be further improved.At the same time,the specific connotation and the formation mechanism of the warm island effect are still unclear.More importantly,plant phenological observations should be employed to reveal the phenological responses of plants to the warm island effect in the lake group area of the Badain Jaran Desert.Based on this,we analyzed the temperature difference between the lake group region of the Badain Jaran Desert and the surrounding areas as well as between the water lake basin and the dry lake basin in the desert hinterland.Climatic data were obtained from Lanzhou University field scientific experimental stations and China National Climate Center standard meteorological stations.Then we studied the phenological responses of plants to the warm island effect in the lake group area of the Badain Jaran Desert by using the digital images.Finally,the formation mechanism of the warm island effect was discussed from the aspects of local circulation,radiation balance and lake heat source contribution.Our study clarified the concept and connotation of the warm island effect in the lake group region of the Badain Jaran Desert and also provided a new scientific basis for the study of lake recharge sources.It will be of important significance for the study on the lake circulation mechanism,the sources of groundwater recharge,land surface processes,ecological system and human activities.

Mots clés : Badain Jaran Desert; lake group region; warm island effect; phenological observation; formation mechanism;

Présentation (CNKI)

Page publiée le 5 juin 2021