Continuous remote sensing ecological index (CRSEI): A novel approach for multitemporal monitoring of eco-environmental changes on large scale

[Display omitted] •The novel CRSEI minimizes error in continuous monitoring of environmental quality.•Multitemporal bias of standard RSEI is reduced with a change detection algorithm.•CRSEI reveals actual environmental-quality changes in East/Southeast Asian coasts.•North China coasts have low environmental quality but see the most improvement.•Southeast Asian coasts see major environmental deterioration caused by human activity. With urbanization and anthropogenic pressures, the eco-environmental quality of East and Southeast Asian coastal regions has undergone drastic changes in the 21st century. To assess these environmental variations and realize regional sustainable development goals, a quantitative monitoring of the eco-environment is necessary, but challenging. The remote sensing ecological index (RSEI) was recently proposed and applied to quantitatively monitor the eco-environmental quality, but bias during multitemporal observations is a major limitation. Thus, a novel method, Continuous Remote Sensing Ecological Index (CRSEI), was developed in this study to enable constant and objective monitoring of large-scale and long-term environmental changes in the coastal regions of East and Southeast Asia. To reduce the multitemporal bias of pixels caused by imaging conditions and sensor status, a change detection algorithm requiring limited auxiliary data was developed. High-resolution images show that the CRSEI enables adequate multitemporal monitoring of eco-environmental changes with fewer false fluctuations on the local scale. The proposed CRSEI should deepen the current understanding of environmental changes and provide a solid scientific reference for environmental protection on multiple scales. The results of this research indicate that the eco-environmental quality of the east and southeast Asian coast remained generally stable during the studied period (2001–2019), with the mean CRSEI changed slightly from 5918 to 5856. However, on a regional level, each area revealed different conditions. First, the Korean Peninsula had relatively stable and well-maintained eco-environmental quality with a CRSEI of around 5500 during 2001–2019. Second, The North China coast had lower eco-environmental quality compared to other regions, but it showed the most improvement, with the CRSEI increasing from 2719 to 2807. Third, the eco-environmental quality of South China and Myanmar's coastal region remained relatively stable, with a CRSEI of around 5730 and 6720, r