Comparison of fire products in Mongolia reveals contrasting results

Fires have become a major concern worldwide because of their serious effects, such as economic losses, alteration of ecosystems often leading to enhanced soil erosion, air pollution, and contribution to global warming through releasing CO2. In Mongolia, the dry climate with strong winds together with the low population number resulting in weak firefighting capabilities forces the generation of fires which are therefore considered the main natural disaster seriously affecting ecosystems and producing dramatic economic damages. Due to the advantages of remote sensing, i.e. wide coverage, high spatio-temporal resolution, easy access, and relatively low expense (or free), satellite data has been widely used for fire studies from local to regional and global scales. Depending on the study area scale, various fire products from different sensors have been used, e.g. the Landsat – TM/ETM+/OLI sensor; the Moderate Resolution Imaging Spectroradiometer (MODIS), the Fire_CCI 5.1 (developed by the European Spatial Agency); and the fire products from the AVHRR sensor. To date, among all the fire products, MODIS data is most widely used in fire-related studies. The new sensor onboard the geostationary Himawari satellite (AHI-8), is providing a new level of data (i.e. very high temporal resolution - 10 minute, along with a high spatial resolution - 0.5 to 2.0 km) for monitoring fires. Since available it has received much attention from the remote sensing application community. However, because this is still a new satellite data, it has not been popularized in applications and research. More studies of assessments and evaluations of this data are needed in various fields, particularly in fire research. In addition, the MODIS instruments were only designed with six years of operating lifetime in mind, therefore both instruments (the Terra and Aqua satellites) are expected to only last until 2020. This makes it necessary to implement a study to evaluate the existing MODIS data, as well as the potential replacement data for fire detection in Mongolia. This motivates us to implement the present study, for which our goals are: (i) to compare the MODIS (MCD64A1) and AHI-8 products in their effectiveness for detecting fires in Mongolia, and (ii) to test the plausibility of the detected fires based on changes in multivariate satellite data before and after the fire events. In order to achieve these goals, we use data from the last five years from July 2015 to July 2019 over the entire Mongolian country. Our results reveal that there is a difference between MODIS and AHI-8 products in detecting fires in Mongolia.