Multi-Temporal Evaluation of Quantitative and Phenological Vegetation Dynamics Using Sentinel-2 Images in North Horr (Kenya)

Abstract

According to the Intergovernmental Panel on Climate Change, the Horn of Africa is getting drier. This research aims at assessing browning and/or greening dynamics and the suitability of Sentinel-2 satellite images to map changes in land cover in a semiarid area. Vegetation dynamics are assessed through a remote sensing approach based on densely vegetated areas in a pilot area of North Horr Sub-County, in northern Kenya, between 2016–2020. Four spectral vegetation indices are calculated from Sentinel-2 images to create annual multi-temporal images. Two different supervised classification methods—Minimum Distance and Spectral Angle Mapper—are then applied in order to identify dense vegetated areas. A general greening is found to have occurred in this period with the exception of the year 2020, with an average annual percentage increase of 19%. Results also highlight a latency between climatic conditions and vegetation growth. This approach is for the first time applied in North Horr Sub-County and supports local decision-making processes for sustainable land management strategies.

Sustainable application of GF-6 WFV satellite data in desert steppe: A village-scale grazing study in China

“…Compared with traditional field surveys and statistical methods, remote sensing monitoring can obtain a wider range of data with relatively little basic work reducing the time and personnel need while the frequency of obtaining ground-based information can be increased. Some satellites have a sensors set in the red-edge band; products obtained through these satellites are also widely used, such as those of Sentinel-2/3, RapidEye, and Gaofen-6 (GF-6) satellites (Dhau et al, 2019;Wang et al, 2019;Bigi et al, 2021;Kang et al, 2021;Xia et al, 2022). Among them, the GF-6 wide-frame camera has set two red-edge bands, Red Edge I and II, in the middle of the red and near-infrared bands, respectively.…”