Środowiskowe Seminarium Fizyki Atmosfery

Remote sensing measurements of land surface temperature (LST) are possible only during clear - sky conditions, what significantly reduces number of available observations of particular targets, especially for Polish cities. Since LST is influenced by synoptic conditions (wind speed) it is widely practiced to use composite datasets for long-term studies. Surface Urban Heat Island (SUHI - Voogt & Oke, 2003) studies commonly adopt temporally composited remote sensing data, what directly increases the clear sky coverage across urban and rural regions. Specification of mean SUHI intensity is a critical step for long-term analyses which might be helpful for the development of mitigation strategies. However, most of SUHI studies did not consider the possible errors caused by composite processes (Hu et al., 2013).Numerous researches in the field of urban climate prove that anthropogenic heat flux (AHF) it is one of the most important components of urban heat island (Sailor & Lu, 2004). AHF is connected with activity of cities' inhabitants, which spatial distribution can be indirectly described by, among others, population density and remotely-sensed night lights (Makar, 2006; Yang, 2014).Analyses of the influence of different temporal aggregation techniques on the urban LST patterns in the city of Warsaw, will be presented. LST data will be obtained by means of MODIS (Moderate Resolution Imaging Spectroradiometer) observations. The study will be conducted for different seasons, for day and night cases. We will discuss impact of different temporal aggregation techniques on values of several SUHI indicators (reviewed by Schwarz et al., 2011), and relationship between LST, night lights (retrieved by DMSP OLI and NPP SUOMI VIIRS satellite instruments) and population density.