A dataset of global sand flux (1950-2021)

Simply, we use all effective friction velocities derived from the instantaneous estimates of 10 m u-component and v-component hourly wind speeds of the ERA5-Land reanalysis product from 1950 to 2021 to infer sand flux based on the physics formulas of blown sand, and according to the existing studies (Gunn et al., 2021; Chanteloube et al., 2022; Gunn et al., 2022a; Gunn et al., 2022b), further improve the conceptual framework of sand flux, and simply define the flux potential (FP), resultant flux potential (RFP) and azimuthal flux potential (FP_N, FP_NNE, FP_NE, FP_NEE, FP_E, FP_EES, FP_ES, FP_ESS, FP_S, FP_SSW, FP_WS, FP_WWS, FP_W, FP_WWN, FP_NW and FP_NNW). Specifically, FP is the sum of FPs moving to all azimuths; RFP is the resultant flux potential, represents net sand transport potential under the different wind directions; RFD is the resultant flux direction, represents net trend of sand flux; FDV is flux directional variability, defined as the ratio of RFP/FP, represents that the flux moves to the same direction (approximate to 1) or many directions (approximate to 0); FP_azimuth represents the azimuthal flux potential, the sum of azimuthal flux potentials is flux potential (FP); RFP_N or RFP_E represent that FPs to all azimuths are projected to the due-north and due-east directions in order to solve the RFP, RFD and the final FDV. All fluxes are the bulk-volume flux, the units are m² yr^-1. Specifically, FP is the sum of FPs moving to all azimuths; RFP is the resultant flux potential, represents net sand transport potential under the different wind directions; RFD is the resultant flux direction, represents net trend of sand flux; FDV is flux directional variability, defined as the ratio of RFP/FP, represents that the flux moves to the same direction (approximate to 1) or many directions (approximate to 0); FP_azimuth represents the azimuthal flux potential, the sum of azimuthal flux potentials is flux potential (FP); RFP_N or RFP_E represent that FPs to all azimuths are projected to the due-north and due-east directions in order to solve the RFP, RFD and the final FDV. References: 1 Gunn, A., Wanker, M., Lancaster, N., Edmonds, D. A., Ewing, R. C. & Jerolmack, D. J. 2021. Circadian rhythm of dune-field activity. Geophysical Research Letters, 48, e2020GL090924. 2 Chanteloube, C., Barrier, L., Derakhshani, R., Gadal, C., Braucher, R., Payet, V., Léanni, L. & Narteau, C. 2022. Source-to-sink aeolian fluxes from arid landscape dynamics in the Lut Desert. Geophysical Research Letters, 49, e2021GL097342. 3 Gunn, A., Casasanta, G., Di Liberto, L., Falcini, F., Lancaster, N. & Jerolmack, D. J. 2022a. What sets aeolian dune height? Nature Communications, 13, 2401. 4 Gunn, A., East, A. & Jerolmack, D. J. 2022b. 21st-century stagnation in unvegetated sand-sea activity. Nature Communications, 13, 3670.简而言之，本研究采用1950年至2021年ERA5-Land再分析产品中10米高度处风场u分量与v分量的逐小时风速瞬时估算值，提取所有有效摩擦速度（friction velocity），基于风沙物理学公式推算输沙通量；同时参考已有研究（Gunn等，2021；Chanteloube等，2022；Gunn等，2022a；Gunn等，2022b），进一步完善输沙通量的概念框架，并明确定义了通量势（flux potential, FP）、合成通量势（resultant flux potential, RFP）以及方位角通量势（azimuthal flux potential, 涵盖FP_N、FP_NNE、FP_NE、FP_NEE、FP_E、FP_EES、FP_ES、FP_ESS、FP_S、FP_SSW、FP_WS、FP_WWS、FP_W、FP_WWN、FP_NW与FP_NNW）。 具体而言，通量势（flux potential, FP）为所有方位方向输沙通量势的总和；合成通量势（resultant flux potential, RFP）代表不同风向条件下的净输沙势；合成通量方向（resultant flux direction, RFD）表征输沙通量的净运移趋势；通量方向变率（flux directional variability, FDV）定义为RFP与FP的比值，用于反映输沙通量沿单一方向（趋近于1）还是多方向分散（趋近于0）。方位角通量势（azimuthal flux potential, FP_azimuth）指特定方位的输沙通量势，所有方位角通量势的总和即为通量势（FP）。RFP_N与RFP_E分别表示将各方位的通量势投影至正北与正东方向，以此求解合成通量势、合成通量方向与最终的通量方向变率。所有输沙通量均为体通量，单位为平方米每年（m² yr⁻¹）。 具体而言，通量势（flux potential, FP）为所有方位方向输沙通量势的总和；合成通量势（resultant flux potential, RFP）代表不同风向条件下的净输沙势；合成通量方向（resultant flux direction, RFD）表征输沙通量的净运移趋势；通量方向变率（flux directional variability, FDV）定义为RFP与FP的比值，用于反映输沙通量沿单一方向（趋近于1）还是多方向分散（趋近于0）。方位角通量势（azimuthal flux potential, FP_azimuth）指特定方位的输沙通量势，所有方位角通量势的总和即为通量势（FP）。RFP_N与RFP_E分别表示将各方位的通量势投影至正北与正东方向，以此求解合成通量势、合成通量方向与最终的通量方向变率。 参考文献： 1. Gunn, A., Wanker, M., Lancaster, N., Edmonds, D. A., Ewing, R. C. & Jerolmack, D. J. 2021. 沙丘场活动的昼夜节律. 地球物理研究通讯, 48, e2020GL090924. 2. Chanteloube, C., Barrier, L., Derakhshani, R., Gadal, C., Braucher, R., Payet, V., Léanni, L. & Narteau, C. 2022. 基于卢特沙漠干旱景观动态的源汇风沙通量. 地球物理研究通讯, 49, e2021GL097342. 3. Gunn, A., Casasanta, G., Di Liberto, L., Falcini, F., Lancaster, N. & Jerolmack, D. J. 2022a. 决定风沙丘高度的关键因素. 自然·通讯, 13, 2401. 4. Gunn, A., East, A. & Jerolmack, D. J. 2022b. 21世纪无植被沙海活动的停滞态势. 自然·通讯, 13, 3670.