Evaluating the influence of temperature fluctuations on soil state in the Maltese Islands using remote sensing techniques

Abstract

Increasing temperatures and droughts present growing environmental challenges in the Mediterranean region, particularly for small island environments like the Maltese Islands where water resources are limited and climate pressures are intensifying. This study examined the spatial and temporal variability of soil surface temperature and soil dryness across the Maltese Islands over a ten-year period (2015–2024) using remote sensing techniques. The analysis focused on seasonal and interannual changes in Land Surface Temperature (LST) and the Temperature Vegetation Shortwave Dryness Index (TVSDI), and on evaluating the relationship between surface temperature and soil dryness under semi-arid conditions. Wet and dry seasons were analysed separately to capture the strong seasonal contrasts characteristic of the Mediterranean climate. Statistical analyses, including correlation and regression tests were applied to assess relationships between LST and TVSDI across districts and seasons. The results revealed a clear seasonal contrast, with dry-season LST values consistently exceeding wet-season values across all districts. While district-level differences in LST were not statistically significant once seasonality was considered, spatial patterns showed persistently higher temperatures in urbanised districts and cooler conditions in rural districts and hydrologically active areas. TVSDI values remained relatively uniform during the wet season, reflecting the homogenising effect of winter rainfall, but exhibited pronounced spatial and temporal variability during the dry season. The South Eastern, Western and Gozo districts consistently recorded the highest dryness levels, with extreme conditions observed in 2016, 2020 and particularly 2024. A strong and statistically significant positive relationship between LST and TVSDI was identified during the dry season, indicating that surface temperature is the dominant driver of soil dryness under moisture-limited conditions. In contrast, weak wet-season relationships highlighted the moderating role of rainfall. Overall, the findings demonstrated the effectiveness of LST-based remote sensing indices for monitoring soil dryness in semi-arid island environments and provided insight into emerging drought trends under ongoing climate change.