Use of Nighttime Light Images in Evaluating Refugee Settlement

In recent years, due to growing number of humanitarian disasters, international attention to refugees has increased. However, many refugee settlements are located in remote areas and there is a lack of relevant surveying data, which leads to the evaluation with difficulties. In this study, we attempt to use nighttime remote sensing to analyze temporal evolution and living conditions of selected refugee camps. First, utilizing monthly nighttime data from the visible infrared imaging radiometer suite with time series analysis, six typical refugee camps in Africa and Asia were selected for a large-scale assessment and comparison, suggesting that time series nighttime light imagery can reflect evolutional trends and economic levels of refugee camps. Second, we use the Kutupalong refugee camp in Bangladesh as a case to show the capacity of the high resolution nighttime light data in retrieving living condition information of the camps, by analyzing the nighttime light data from sustainable development goals satellite-1 combined with humanitarian points of interest data. Specifically, based on spatial analysis (e.g., hotspot analysis), the distribution pattern of nighttime light in the camp was further explored, and the sanitation security situation in the camp was assessed. This study demonstrates that nighttime remote sensing imagery is potentially useful in evaluating refugee camps around the world, providing technical support to international humanitarian relief work.