**Satellite and Ground Measurements for Studying the Urban Heat Island Effect in Cyprus**

Diofantos G. Hadjimitsis, Adrianos Retalis, Silas Michaelides, Filippos Tymvios, Dimitrios Paronis, Kyriacos Themistocleous and Athos Agapiou

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/39313

**1. Introduction**

An urban heat island (UHI) is a phenomenon whereby an urban area experiences elevated air temperatures due to anthropogenic modification of the environment and is usually more evident at night. During heat waves the local effect of an UHI is superimposed on the re‐ gional temperature field and as a result heat stress is enhanced. Both the intensity and the spatial structure of the observed thermal contrast of the UHI depend on various parameters, such as the structure of the urban tissue, the population density and its associated heat re‐ lease, the land use patterns, the vegetation cover, the surface topography and relief etc. In general terms, the UHI is becoming more intense as city sizes increase. Traditional measure‐ ments of the near-surface UHI are based on measurements of the air temperature using ur‐ ban and rural weather stations or air temperature transects. Thermal satellite sensors, which primarily measure the radiance at the top of the atmosphere in the thermal infrared, retrieve the so called land surface temperature (LST) which is the temperature measured at the Earth's surface and is regarded as its skin temperature. Given that LST is different from the surface air temperature, a distinction is made in remote sensing studies between surface ur‐ ban heat island (SUHI) and atmospheric heat island (e.g., Nichol, 1996).

Several studies published in the literature have focused on the use of remotely sensed data for studying the urban heat island effect (Dousset & Gourmelon, 2003; Kato & Yamaguchi, 2005; Lo & Quattrochi, 2003; Streutker, 2002; Tran et al., 2006; Xiao et al., 2007; Yuanbo et al., 2007). Other relevant studies are focusing on the validation of satellite LST retrievals with

© 2013 Hadjimitsis et al.; licensee InTech. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2013 Hadjimitsis et al.; licensee InTech. This is a paper distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

ground measurements or on the inter-comparison of LST products from different sensors (Mostovoy et al., 2005; Nichol et al., 2009; Retalis et al., 2010). The availability of a multitude of data archives (e.g., from MODIS, ASTER and Landsat TM/ETM+ sensors) with long timeseries has recently raised the scientific interest in the relevant field. As a result, several stud‐ ies have been published on the study of the UHI effect for various cities of the world (Hung et al. 2006; Imhoff et al., 2010; Peng et al., 2012).

ban expansion (see Fig. 3). As it was found from previous studies (Hadjimitsis et al., 2011), there has been an increase of urban areas of more than 100% compared to late 1980's and a decrease of 20% of rural areas. These results were derived from an analysis of multi-tempo‐

Satellite and Ground Measurements for Studying the Urban Heat Island Effect in Cyprus

http://dx.doi.org/10.5772/39313

3

ral satellite image classification.

**Figure 1.** Main morphological regions of Cyprus

**Figure 2.** Districts of Cyprus

This Chapter discusses the urban heat island effect in Cyprus based on both multi-temporal satellite and meteorological data. The necessary information of the study area is provided in Section 2. The description and selection of the heat waves and the analysis of the synoptic conditions favouring the development of heat waves are discussed in Section 3. The devel‐ opment of a Neural Network for the correlation of satellite derived land surface temperature (LST) with ground based air surface temperature is examined in Section 4. The analysis of satellite derived LST for studying the temporal evolution of LST and the deviation of LST (anomaly) from the mean values during a heat wave event are presented in Section 5, while Section 6 refers to the calculation of the mean monthly magnitude of urban heat island (UHI) for the period 2002-2008 and for selected heat wave events.
