The rapid Land Use and Land Cover change analysis using the Sentinel-2 images in Google Earth Engine: A Case Study of Xiong’an New Area from 2017 to 2020

Abstract

Land Use and Land Cover (LULC) are the basic units of human activities and also serve as the significant factors to assess the climate change studies and environmental protection. Therefore, it is of significance to accurately and timely obtain the LULC maps on the earth’s surface, in particular for those regions where dramatic LULC changes are undergoing. Since 2017 April, a new state-level new area, Xiong’an New Area, was established in China, which would inevitably lead to some LULC changes in this region. In order to better understand what kinds of LULC change in this region with more details and further evaluate the potential impacts that the LULC changes will bring, this study makes full use of the 10-m multi-temporal Sentinel-2 images on the cloud-computing Google Earth Engine (GEE) and the powerful classification capability of Random Forest (RF) models, to generate the continuous LULC maps in Xiong’an New Area from 2017 to 2020. The derived LULC map for each year in Xiong’an New Area achieves high accuracy, with OA and Kappa values less than 0.9. Based on the obtained LULC maps, this study analyzed the spatial and temporal changes of LULC types in the last four years. It revealed that the estimated dry farmland has decreased from 2017 to 2018 and then kept almost stable, and the majority of it has converted to non-cropland, especially to the tree seedlings and landscape dual-use regions. The estimated impervious areas that were mainly composed of buildings and transport infrastructures first increased due to the newly constructed Xiong’an Station with some high-speed roads and then decreased from 2019 to 2020, mainly due to the relocation of some small villages. Accordingly, some building groups and aggregations were going to show in this region, and are expected to further developed in the future. Other LULC types such as lakes and forests have not changed dramatically, indicating that the environmental protection in Xiong’an New Area was, to date, satisfactory. The obtained 10-m and 4-year LULC maps in this study can provide some valuable information on the monitoring and understanding of what kinds of changes were and will be undergoing in Xiong’an New Area, and can also be used for evaluating the potential impacts and challenges such as environmental protection. Additionally, the utilization of GEE and the multi-temporal 10-m Sentinel-2 images can help to achieve LULC mapping in this region in an accurate and timely manner, which can be used in future studies.