The seif dune field over the gravel desert surface in the eastern margin of the Kumtagh Desert is a valuable experimental site for the observation of dune formation and dynamics.We used high-resolution remote sensing ...The seif dune field over the gravel desert surface in the eastern margin of the Kumtagh Desert is a valuable experimental site for the observation of dune formation and dynamics.We used high-resolution remote sensing and station observation approaches,combined with wind and grain size data,to study the characteristics of the aeolian environment and the morphologies of and dynamic changes in seif dunes.We observed the ratio of the resultant drift potential(RDP)to the drift potential(DP),which was 0.37,associated with an obtuse bimodal wind regime.The drift potentials in the west-northwest(WNW)and east-northeast(ENE)directions were dominant,and the angle between the two primary DP directions was 135.00°.The dune orientations ranged from 168.75°-213.75°,which were parallel to the resultant drift direction(186.15°).The dune lengths ranged from 51.68 to 1932.1 m with a mean value of 344.91 m.The spacings of the dunes ranged from 32.34 to 319.77 m with a mean value of 93.39 m.The mean grain size of the sediments became finer,and the sorting became better from upwind tail to downwind tip,which indicated that the sediment of the seif dunes in the study region may be transported from northward to southward.The rate of increase in the length,the mean longitudinal migration rate of the dune tail,and the mean longitudinal extension rate of the dune tip(also called elongation rate)were 4.93,4.63,and 9.55 m/a,respectively.The mean lateral migration vector of the seif dunes was approximately 0.11 m/a towards the west(-0.11 m/a),while the mean amplitude of lateral migration was 0.53 m/a,ignoring the direction of lateral migration.We found that the seif dune field formed first beside seasonal rivers,which can provide sediment,and then expanded downwind.展开更多
基金the Fundamental Research Funds for the Central Non-profit Research Institution of Chinese Academy of Forestry(CAFYBB2019MA009,CAFYBB2017ZE005)the New Project of Surplus Project Fund for Institute of Desertification Studies,Chinese Academy of Forestry(IDS2019JY-4)+1 种基金the National Natural Science Foundation of China(41471151,41701010,41877530)the Youth Innovation Promotion Association of Chinese Academy of Sciences(2018459).
文摘The seif dune field over the gravel desert surface in the eastern margin of the Kumtagh Desert is a valuable experimental site for the observation of dune formation and dynamics.We used high-resolution remote sensing and station observation approaches,combined with wind and grain size data,to study the characteristics of the aeolian environment and the morphologies of and dynamic changes in seif dunes.We observed the ratio of the resultant drift potential(RDP)to the drift potential(DP),which was 0.37,associated with an obtuse bimodal wind regime.The drift potentials in the west-northwest(WNW)and east-northeast(ENE)directions were dominant,and the angle between the two primary DP directions was 135.00°.The dune orientations ranged from 168.75°-213.75°,which were parallel to the resultant drift direction(186.15°).The dune lengths ranged from 51.68 to 1932.1 m with a mean value of 344.91 m.The spacings of the dunes ranged from 32.34 to 319.77 m with a mean value of 93.39 m.The mean grain size of the sediments became finer,and the sorting became better from upwind tail to downwind tip,which indicated that the sediment of the seif dunes in the study region may be transported from northward to southward.The rate of increase in the length,the mean longitudinal migration rate of the dune tail,and the mean longitudinal extension rate of the dune tip(also called elongation rate)were 4.93,4.63,and 9.55 m/a,respectively.The mean lateral migration vector of the seif dunes was approximately 0.11 m/a towards the west(-0.11 m/a),while the mean amplitude of lateral migration was 0.53 m/a,ignoring the direction of lateral migration.We found that the seif dune field formed first beside seasonal rivers,which can provide sediment,and then expanded downwind.
