Second , according to field investigation and wind - tunnel experiment , some scholar s advanced that barchan dunes often appear in dynamic equilibrium shapes when th ey move along the direction perpendi cular to the dune ridge under the influence of unimodle sand - moving wind 风成沙的红化和圆度特征不宜作为判别其气候意义的诊断性标志，应当结合动植物化石及石英砂显微结构等线索来确定。
