Impacts of Vegetation and Topography on Land Surface Temperature Variability over the Semi-Arid Mountain Cities of Saudi Arabia

Ahmed Ali Bindajam,Javed Mallick,Saeed Alqadhi,Chander Kumar Singh,Hoang Thi Hang

doi:10.3390/atmos11070762

Abstract

Land surface temperature (LST) can fully reflect the water–heat exchange cycle of the earth surface that is important for the study of environmental change. There is little research on LST in the semi-arid region of Abha-Khamis-Mushyet, which has a complex topography. The study used LST data, retrieved from ASTER data in semi-arid mountain areas and discussed its relationship with land use/land cover (LULC), topography and the normalized difference vegetation index (NDVI). The results showed that the LST was significantly influenced by altitude and corresponding LULC type. In the study area, during the summer season, extreme high-temperature zones were observed, possibly due to dense concrete surfaces. LST among different types of land use differed significantly, being the highest in exposed rocky areas and built-up land, and the lowest in dense vegetation. NDVI and LST spatial distributions showed opposite trends. The LST–NDVI feature space showed a unique ABC obtuse-angled triangle shape and showed an overall negative linear correlation. In brief, the LST could be retrieved well by the emissivity derived NDVI TES method, which relied on upwelling, downwelling, and transmittance. In addition, the LST of the semi-arid mountain areas was influenced by elevation, slope zenith angle, aspect and LULC, among which vegetation and elevation played a key role in the overall LST. This research provides a roadmap for land-use planning and environmental conservation in mountainous urban areas.

Highlights

Mountains are well-known drivers of climate change and growth in global mass and energy balance.Extreme topographical variability introduced in mountain areas creates complex spatial–temporal patterns of meteorological and hydrological process, and ecological parameters with high gradients of attitude at short distances [1,2,3,4]
Satellite-borne thermal infrared remote (TIR) sensors receive electromagnetic radiation (EMR) that can be directly measured as Top of Atmosphere (TOA) radiance measurements
Land surface temperature (LST) Result from Emissivity Derived from the Proportion of Vegetation Cover in Conjunction with normalized difference vegetation index (NDVI)

Summary

Introduction

Mountains are well-known drivers of climate change and growth in global mass and energy balance.Extreme topographical variability introduced in mountain areas creates complex spatial–temporal patterns of meteorological and hydrological process, and ecological parameters with high gradients of attitude at short distances [1,2,3,4]. Mountains are well-known drivers of climate change and growth in global mass and energy balance. Mountain ecosystems are very vulnerable to natural and anthropogenic changes, compared to lowland ecosystems. Analysis of atmospheric surface processes in mountain regions. The TOA radiances are transformed to LST by correction for three major influences; angular effects [5], atmospheric absorption and scattering [6], and surface spectral emissivity values [7]. Such corrections are carried out using complex algorithms, alongside thorough validation and evaluation, resulting in a final product that a climate scientist might use [8]

Objectives

Methods

Results

Discussion

Conclusion