Air Surface Temperature Variability and Trends from Satellite Homogenized Time Series Data Over Tunis 2003–2021

Monthly Air Surface Temperature (AST) data for Tunis were acquired by the Atmospheric InfraRed Sounder (AIRS) dataset (2003–2021), the enrolments of 77 grids, each located in Spatial resolution 1°x1°, were converted into monthly and annual data and analysed. The time series of AST in Tunis were investigated for temporal and spatial trends during study period over six climate stations each having sufficient data available were utilized for this purpose. The monthly time series showed similar variations and fluctuated of AST, minimum (decreases, January) and maximum (increases, July) in trend, with standard deviation (294.15 + 14.02 K°). Most stations, appeared positive trends in their annual AST series, only at Sfax negative, with higher trends for central stations than those closer to the desert and coast. The trends were lowest over coastal area. The Comparisons among selected six stations (Tunis, Tabarka, Thala, Sfax, Medenine, and EL-Borma) between the AST observed by AIRS and in-situ data showed close agreement range from 0.38 to 3.6 K°, and approximately the same in the north-to-south transect throughout the year. The validation results plainly evident a high correlation coefficient (R, 0.995, 0.997, 0.994, 0.94, 0.974 and 0.95), and the asset values of (R²) was 0.991, 0.995, 0.987, 0.93, 0.993, and 0.977 for Tunis, Sfax, Tabarka, Thala, Medenine, and EL-Borma respectively. The satellite observation (AIRS) is able to investigate the variations of the atmosphere AST over different zones.