Urban greening resources and visibility-soil-moisture coordination in Dubai: Spatiotemporal patterns, spatially...

Urban greening in desert cities is closely related to atmospheric visibility and near-surface water conditions, yet its environmental performance depends on vegetation condition, landscape configuration, atmospheric context, and irrigation demand. Taking Dubai as the study area and 2010, 2015, and 2020 as reference years, this study integrates Landsat imagery, GLC_FCS30D land-use data, atmospheric visibility, precipitation, and surface soil moisture to examine the spatial and temporal coordination between visibility-related atmospheric conditions and water availability. It further analyzes the changes in the Normalized Difference Vegetation Index (NDVI), Fractional Vegetation Cover (FVC), Leaf Area Index (LAI), and the landscape patterns of different land-use types. An optimal-parameter geographical detector, ordinary least squares regression, and geographically weighted regression are used to identify the stage-dependent and spatially varying associations between urban greening resources and environmental coordination.The principal finding is that the relationship between urban greening resources and the visibility-soil-moisture coordination index was both stage-dependent and spatially nonstationary. FVC was the dominant individual factor in 2010 and 2020, whereas ED dominated in 2015, while the direction and magnitude of local effects varied among coastal built-up areas, urban expansion fringes, and inland desert areas. The results further show that: (1) Mean visibility generally declined during the study period, whereas surface soil moisture decreased from 2010 to 2015 and subsequently recovered from 2015 to 2020. Areas with low coordination gradually shifted from the southeastern and southern parts of the study area towards the central urban area, indicating a spatial mismatch between atmospheric visibility and surface water conditions. (2) From 2010 to 2020, the proportion of bare land decreased by 2.88 percentage points, whereas impervious surfaces and managed vegetation increased by 1.72 and 1.56 percentage points, respectively. The edge density and patch density of managed vegetation increased continuously, indicating that the expansion of green spaces was accompanied by increasing landscape fragmentation. During the same period, NDVI increased by a dynamic degree of 1.15%, whereas FVC decreased by 0.93% and LAI changed only slightly, with a dynamic degree of -0.08%. These results indicate that local vegetation greenness improved without a corresponding increase in continuous vegetation coverage or canopy structure. (3) The explanatory power of the driving factors was strongly stage-dependent. FVC was the dominant factor in 2010 and 2020, whereas edge density was dominant in 2015. The interaction effects between vegetation indicators and landscape-pattern metrics were generally stronger than the effects of individual factors, indicating that vegetation condition and landscape structure jointly differentiated the coordination state. (4) The coefficients of FVC, edge density, and patch density varied substantially across locations and years, demonstrating spatially varying associations between urban greening resources and environmental coordination. These findings suggest that urban greening should be planned according to local vegetation conditions, landscape structure, atmospheric visibility, ventilation requirements, and water availability. Coastal built-up areas, urban expansion fringes, inland areas, and central urban districts should therefore adopt differentiated vegetation configurations and irrigation strategies. This study provides a basis for coordinating urban greening, atmospheric-environmental conditions, landscape structure, and water-resource allocation in arid cities.