The sand drift potential (DP, in vector units (VU)) is calculated by

 DPi=∑U ²×(U-Ut)/100×t

 where i represents the 16 wind directions (N, NNE, NE, NEE, E, EES, ES, ESS, S, SSW, WS, WWS, W, WWN, NW and NNW); U is the mean wind speed in each speed category with an effective wind speed greater than or equal to the threshold wind speed Ut at 10 m height; Ut = 5.3 and 5.8 m s-1 is the threshold wind speed corresponding to the reference diameter d = 0.25 and 0.30 mm, which is the minimum wind speed at the 10 m height to cause sand in saltation; t is time wind blew, expressed as a percentage in a wind summary. The 2 m s-1 bin is adopted in each direction of effective winds ≥5.3 m s-1 (≥5.8 m s-1), corresponding to mean wind speeds of 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32 and 33 m s-1 (7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31 and 32 m s-1), and the sum of these bins is the final DP in the wind direction. Note that these mean wind speeds have been expressed in knots by the conversion factor (1 knot = 0.5144 m s-1) to ensure the valid classification of wind energy environments (low energy, <200 VU; intermediate energy, ≥200 VU and <400 VU; high energy, ≥400 VU) developed by Fryberger.

 The obtained DPs in the 16 wind directions are projected onto the due-east (RDP_E) and due-north (RDP_N) directions to calculate the RDP, RDD and WDV:

 RDP = sqrt(RDP_E ² + RDP_N ²)

 RDD = 180 + 57.296atan2(RDP_E ⁄ RDP_N)

 WDV = RDP / DP

 Notably, the divisor used in calculating the percentage of effective winds from different directions is the total hour number of Julian years (8760 hours for common years or 8784 hours for leap years).

 The wind speed and direction data calculated by 10 m u-component of wind and 10 m v-component wind were from the 0.25° ERA5 hourly wind data during 1940-2025 and the 0.1° ERA5-Land hourly wind data during 1950-2025.

 The drift potential (DP) represents the sum of DPs from the 16 wind directions. The resultant drift potential (RDP) indicates net sand transport potential under different wind directions, while the resultant drift direction (RDD) reflects the net trend of sand drift. Wind directional variability (WDV) is defined as the ratio of RDP to DP, indicating whether winds predominately come from a single direction (approaching 1) or from multiple directions (approaching 0). Specifically, DP_Azimuthal refers to the drift potential from a given wind direction. RDP_E and RDP_N represent the projections of the DPs from the 16 wind directions onto the due-east and due-north directions, respectively, which are used to calculate the RDP, RDD and the final WDV. DP_azimuthal_bin is the DP in the 2 m s-1 bin of the wind direction. Azimuthal_absolute frequency represents the count of sand-moving winds in the 2m s-1 bin of the wind direction; azimuthal_relative frequency represents the frequency of sand-moving winds in the 2 m s-1 bin of the wind direction. All data are stored in GeoTIFF format.