Remote sensing assessment of changes of surface parameters in response to prolonged drought in the arid zone of central Iran (Gavkhoni playa)

Remotely-sensed normalized difference vegetation index (NDVI) and land surface temperature (LST) are significant indicators for evaluating the environmental consequences of climate changes in arid regions. Understanding of the relationship between these changes and land surface properties of the arid regions is important in land planning. The Gavkhoni playa is a closed basin in the arid zone of Iran that has recently undergone significant environmental changes due to decreasing precipitations. The objective of this study was to explore the spatiotemporal changes of its LST and NDVI before and after the drought event of 2014–2018. Through the application of an integrated method based on cellular fractal model and continuous wavelet transform (CWT), we investigated the relationship between variation of surface fractal dimension and distribution of LST and NDVI changes before and after the drought. The results indicated substantial changes in LST and NDVI values associated with the onset of drought conditions. Changes in the spatial distribution of LST and NDVI were particularly high in the central playa area, the western and southern sides of the playa, including the salt lake, the wetlands, and the clay flat. These areas correspond to the zone 4 of the fractal dimension map where extreme topographic anomaly and complexity. Wavelet analysis confirmed the relationship between the surface fractal dimension pattern and anomalies in LST and NDVI variations. The investigation highlighted the ability of the integrated application of the cellular fractal model and wavelet analysis to quantify the relationship between land surface properties and the spatial variation of LST and NDVI in changing environmental conditions.