Dynamics of wind ripples and dune morphology

我们在日本西南部鸟取沙丘的不同斜坡上收集了684个风波纹的横截面。结果表明：上升风波纹的波长（12 cm）大于下降风波纹的波长（6 cm），随着前进角的增加，波浪变长；根据处理角度将截面形状分为四种类型。在上升和下降条件下，风波纹的临界推进角分别为24°和17°。另一方面，根据等高线地图的测量，横向沙丘的斜坡角度在7°左右占主导地位。

We collected 684 cross sections of wind ripples from various slopes at the Tottori Sand Dunes, southwest Japan. The results show that the wave-lengths of ascending wind ripples(12 cm) were larger than those of the descending ones(6 cm): as the proceeding angles increased, the waves became longer. The cross-sectional shapes were classified into four types according to the proceeding angles. The critical proceeding angles of the wind ripples under the ascending and descending conditions were 24°and 17°, respectively. On the other hand, the angles of stoss-side slopes of transverse dunes are dominant in ca 7°according to measurements using contour maps.