沙漠流动性的气候评价  

MOBILITY OF DUNEFIELDS IN RELATION TO CLIMATE

作　　者：董治宝[1] 吕萍[1] 胡光印[1] 

机构地区：[1]中国科学院寒区旱区环境与工程研究所沙漠与沙漠化重点实验室,兰州730000

出　　处：《第四纪研究》2013年第2期276-282,共7页Quaternary Sciences

基　　金：国家重大科学研究计划项目"青藏高原沙漠化对全球变化的响应"(批准号:2013CB956000)资助

摘　　要：流动性是沙漠或沙丘的突出特征之一,是风沙运动的产物,与气候关系密切。然而,目前尚没有被广泛接受的沙漠或沙丘流动性与气候关系的研究成果和评估方法。本文简要评述了在沙漠流动性和气候关系方面的一些代表性研究工作,讨论了目前研究存在的问题,展望未来发展趋势。研究者们曾提出风蚀气候指数、输沙势以及沙丘活动指数,试图表达沙漠流动性与主要气候要素,如风速和降水量之间的关系。风蚀气候指数主要针对土壤风蚀,根据风沙活动强度与风速以及土壤湿度的经验关系,通过风速和降水-蒸发指数表达气候侵蚀性。输沙势针对流动沙丘的形成和发育环境,适用于表达干旱流动沙丘区的潜在风沙活动强度。沙丘活动指数与风蚀气候指数类似,但更适用于流动或固定沙丘区,是判断沙丘流动程度的指数。沙漠的流动性不仅与气候特征有关,而且与当地总体地理环境背景、地表沉积物物理化学性质等有关。沙漠的流动性变化相对于气候变化具有滞后性,因而在气候变化的背景下,沙漠流动性与气候的对应关系变差。如何针对不同区域,表达气候要素对沙漠流动性的影响,以及沙漠流动性对气候变化的响应是需要深入研究的问题。Mobility is a striking character of dunefields,which results from blown sand movement and is closely related to climate. However, it is a complex issue to express the relationship between dunefield mobility and climate. Considerable efforts have been devoted to relating dunefield mobility to climate,but widely accepted methods and results are not available yet. This paper reviews several representative indexes proposed to assess the mobility of dunefields in relation to climatic variables. Wind erosion climatic factor, drift potential and mobility index have been proposed to relate dunefield mobility to primary climate elements such as precipitation and wind. The wind erosion climatic factor proposed by USDA scientists mainly concerns the climate erosivity for soil. The drift potential proposed by aeolian geomorphologists are used to characterize wind regime responsible for aeolian geomorphology. Dune mobility index are proposed to recognize the mohility and stability of dunes. All methods start from the fact that wind speed and sediment moisture significantly affect the movement of blown sand. Sediment moisture is in turn determined by the precipitation effect. However, relation of sediment moisture to precipitation effect contained in various formulas usually lacks sound basis. The relationship between dunefield mobility and climate also differs from region to region, as a result of the local climate background and sediment characteristics. The response lag of dunefield mobility to climate change sometimes results in the poor correspondence of climatic factors to dunefield mobility when the climate is changing. It is suggested that defining the significances of climatic variables in dunefiled mobility accounting for regional conditions and responses of dunefield mobility to climate change will be a future research need.

关 键 词：沙漠流动性 气候 风蚀气候指数 沙漠流动性指数 

分 类 号：P941.73[天文地球—自然地理学]