Observational Characteristics and Meteorological Drivers of Inferior Mirages in Kumtag Desert, China

Abstract

Mirages are virtual images formed when light reflected from surface objects is refracted by the atmosphere, and they are generally classified into superior and inferior mirages. The Kumtag Desert in Xinjiang, China, strong near-surface vertical temperature lapse rates are common there, favoring the occurrence of inferior mirages. The annual occurrence frequency reaches 98.9%. Using in real-time camera monitoring mirage images and meteorological data collected from September 2022 to August 2024, this study analyzed the observational characteristics and meteorological drivers of inferior mirages. Based on the occurrence period, image coverage, boundary clarity, and morphological characteristics, inferior mirages can be divided into three grades. The results show that the duration of inferior mirages in the Kumtag Desert is longer in summer and shorter in winter, and the mirage intensity level is higher in summer and lower in winter. Mirages are most frequently observed from 10 to 18 and are clearest around noon. The morphological features of mirages decrease with increasing observation height. Mirage level is positively correlated with air temperature, visibility, sunshine duration, near-surface temperature (0–100 cm), vertical temperature difference, and wind speed, and negatively correlated with relative humidity. Therefore, mirages are more likely to occur on sunny days in the warm season.