Monitoring of land surface radiative parameters in Bucharest city through thermal infrared remote sensing

Abstract

This paper aims to investigate the influences of urban growth and green land cover decrease on land surface radiative properties and metropolitan climate of Bucharest in Romania. Remote sensing data from Landsat TM/ETM/OLI, Sentinel 2 and time series MODIS Terra/Aqua thermal infrared sensors as well as in-situ meteorological data have been used to assess urban land cover– air and land surface temperature interactions over period between 2000 and 2019 years. The air (Ta) and land surface temperature (Ts), key parameters for urban climate research, were analyzed in relation with variables land surface albedo and Normalized Difference Vegetation Index (NDVI) at city level. Based on these parameters, the urban growth, Urban Heat Island (UHI) effect and the relationships of Ts to other biogeophysical parameters have been analyzed. The correlation analyses revealed that, at the pixel-scale, Ta and Ts possessed a strong positive correlation with percent impervious surfaces and negative correlation with vegetation abundances at the regional scale, respectively. Was also analyzed UHI phenomenon during extreme heat waves events. Our results suggest that monthly mean UHI intensity is between 1°C and 6°C, and the most intense UHI occurs in day-time in the summer period during heat waves periods. The analysis shows that different urban/periurban zones and landscapes bring diurnally and seasonally different contributions to the local and regional thermal environment. City land cover was the most important contributor to increases in regional Ts. Vegetation had a clear cooling effect as the normalized vegetation difference index (NDVI) increased during summer periods.