地貌学领域自然科学基金项目申请资助、研究范式与启示

地理科学研究关注地球表层系统的人-地关系及其相互作用机理,地理要素的配置规律、成因是重要基础[1,2].地貌作为一种关键地理要素,是地表过程的基础承载,其形成过程和演化历史体现了地球表面与深部过程的相互作用[3,4],而其时空变化特征又影响着地表过程发生的频率与幅度[5,6].因此,地貌学作为地理科学的重要分支学科,其研究充分体现了地理科学所固有的综合性、交叉性和区域性特点.同时,得益于地理科学理论的深化[7]以及技术手段的不断丰富[8],地貌学与其他学科不断交叉融合、取长补短,逐步发展出生态地貌学[9,10]、行星地貌学[11,12]等新兴前沿交叉学科.然而,相较于我国地理科学其他分支学科及国际地貌学的发展态势[13~16],近20年来,我国地貌学发展相对缓慢、学科地位逐渐弱化、后续人才储备相对不足[17,18].

Quantitative analysis of planation surfaces of the upper Yangtze River in the Sichuan-Yunnan Region, Southwest China

Identification of the planation surfaces (PSs)is key for utilizing them as a reference in studying the long- term geomorphological evolution of the Upper Yangtze River Basin in the Sichuan-Yurman region,Southwest China.Using a combined method of DEM-based fuzzy logic and topographic and fiver profiles analysis and based on a comprehensive analysis of four morphometfic parameters:slope,curvature,terrain raggedness index, and relative height,we established the relevant fuzzy membership functions,and then calculated the membership degree (MD)of the study area.Results show that patches with a MD>80% and an area>0.4 km^2 correspond well to the results of Google Earth and field investigation,representing the PS remnants.They consist of 1764 patches with an altitude,area,mean slope,and relief of mostly 2000-2500 m above sea level (asl),0-10 km^2,4°-9°,0-500 m,respectively,covering 9.2% of the study area's landscape,dipping to southeast,decreasing progressively from northwest to southeast in altitude,and with no clear relation between each patch's altitude and slope,or relief.All these results indicate that they are remnants of once regionally continuous PSs which were deformed by both the lower crust flow and the faults in upper crust,and dissected by the network of Upper Yangtze River.Additionally,topographic and river profiles analysis show that three PSs (PS1-PS3)well developed along the main valleys in the Yongren-Huili region, indicating several phases of uplift then planation during the Late Cenozoic era.Based on the incision amount deduced from projection of relict river profiles on PSs, together with erosion rates,breakup times of the PS 1,PS2,and PS3 were estimated to be 3.47 Ma,2.19 Ma,and 1.45 Ma,respectively,indicating appearance of modem Upper Yangtze River valley started between the Pliocene to early Pleistocene.

Geological and surfacial processes and major disaster effects in the Yellow River Basin

The Yellow River Basin(YRB) is characterized by active geological and tectonic processes, rapid geomorphological evolution, and distinct climatic diversity. Correspondingly, major disasters in the YRB are characterized by varied types,extensive distributions, and sudden occurrences. In addition, major disasters in the YRB usually evolve into disaster chains that cause severe consequences. Therefore, major disasters in the YRB destroy ecologies and environments and influence geological and ecological safety in the basin. This paper systematically reviews research on geological and surface processes, major disaster effects, and risk mitigation in the YRB, discusses the trends and challenges of relevant research, analyzes the key scientific problems that need to be solved, and suggests prospects for future research based on the earth system science concept. Themes of research that should be focused on include geological, surface and climatic processes in the YRB and their interlinking disaster gestation mechanisms;formation mechanisms and disaster chain evolutions of giant landslides in the upper reach of the YRB;mechanisms and disaster chain effects of loess water-soil disasters in the middle reach of the YRB;occurrence patterns and amplifying effects of giant flood chains in the lower reach of the YRB;and risk mitigations of major disasters in the YRB. Key scientific problems that need to be solved are as follows: how to reveal the geological, surface and climatic processes that are coupled and interlinked with gestation mechanisms of major disasters;how to clarify the mutual feedback effects between major disasters and ecology;and how to develop a human-environmental harmony-based integrated risk mitigation system for major disasters. Prospects for future studies that follow the earth system science concept include the following: highlighting interdisciplinary research to reveal the interlinked disaster gestation mechanisms of the geology, surface and climate in the YRB in the past, present, and future;forming theories to clarify the regional patterns, dynamic mechanisms, and mutual-feedback effects between disaster chains and ecology in the YRB on land and in rivers in the region;solving technological bottlenecks to develop assessment models and mitigation theories for integrated risks in the YRB by following the human-environment harmony concept;and finally, establishing a demonstratable application pattern characterized by "whole-basin coverage" and "zonal controls", thereby guaranteeing ecological and geological safety in the basin and providing scientific support for ecological conservation and high-quality development of the YRB.

Numerical simulation of landscape evolution and mountain uplift history constrain——A case study from the youthful stage mountains around the central Hexi Corridor,NE Tibetan Plateau

Landscape evolution models(LEMs)are essential tools for analyzing tectonic-climate interactions and reproducing landform-shaping processes.In this study we used a LEM to simulate the evolution of the mountains from the central Hexi Corridor in the northeastern Tibetan Plateau,where the climate is arid and the surface processes are relatively uniform.However,there are pronounced differences in the topography between the mountains around the central Hexi Corridor.The East Jintanan Shan,West Jintanan Shan and Heli Shan are located in the northern part of the corridor;and the Yumu Shan in the southern part.Firstly,several representative areas were selected from these mountains to analyze the topographic characteristics,including the uniform valley spacing,local relief,and the outlet number.Secondly,a LEM for these areas was constructed using the Landlab platform,and the landscape evolution was simulated.With uniform valley spacing and other topographic characteristics as the criteria,we compared the realistic and simulated terrain for different model ages.Finally,based on the similarity of the simulated and realistic terrain,we estimated the timing of the initial uplift and the uplift rate of the four mountain ranges.The results are consistent with previous geological and geomorphological records from these youthful stage mountains that have not yet reached a steady state.Our findings demonstrate that LEMs combined with topographic characteristics are a reliable means of constraining the timing of the initial uplift and the uplift rate of the youthful stage mountain.Our approach can potentially be applied to other youthful stage mountains and it may become a valuable tool in tectonic geomorphology research.