URBAN HEAT AND CO2 FLUXES

The Eddy Covariance method uses the turbulent transport theory in the surface layer of the atmosphere, and estimates gas and energy fluxes from the covariance between vertical wind speed and the gas concentration and temperature at a measured height above the surface. With eddy covariance, the exchange of various gases and energy between the atmosphere and the underlying surface can be measured. The installed systems in Heraklion measure latent and sensible heat fluxes, as well as CO2 fluxes. Τhe measurements are representative of a wide area around the sensors (footprint) that are estimated to cover a significant part of the surrounded area.

REAL TIME MEASUREMENTS

HECKOR

The Eddy Covariance system, at Heraklion city centre, is equipped with the IRGASON Integrated CO2 / H2O Open-Path Gas Analyser and a 3D Sonic Anemometer (Campbell Scientific, Inc, Utah, USA). It is installed on the roof of a high building in the center of Heraklion (Kornarou Square) since October 2016. The sensor is mounted on a 10 meter telescopic mast in order to reach the appropriate height (27 m) over the urban canopy layer and measure a blended, spatially averaged signal. The system is also equipped with a CNR1 Net Radiometer (Kipp & Zonen B.V. Delft) to measure incoming and outgoing shortwave and longwave radiation.

REAL TIME MEASUREMENTS

HECMAS

The Eddy Covariance system, at Mastambas, is equipped with the IRGASON Integrated CO2 / H2O Open-Path Gas Analyser and a 3D Sonic Anemometer (Campbell Scientific, Inc, Utah, USA). It is installed on the roof of a public elementary school since April 2021. The sensor is mounted on a 17 meter tower in order to reach the appropriate height (24 m) over the urban canopy layer and measure a blended, spatially averaged signal. The system is also equipped with a CNR4 Net Radiometer (Kipp & Zonen B.V. Delft) to measure incoming and outgoing shortwave and longwave radiation and an air temperature and relative humidity probe (Rotronic).

Parameter HECKOR HECMAS Units
Ground Height 30 69 (m)
Latitude 35.3361 35.3234 (degrees_north)
Longitude 25.1328 25.1302 (degrees_east)
Measurement Height Above Ground 27 24.6 (m)
Mean Building Mean Height (400m. Radius) 11.3 8.5 (m)
Standard Deviation of Building Height (400m. Radius) 4.7 3.4 (m)
Maximum Building Height (400m. Radius) 30.5 21.2 (m)
Plan Area Index 0.5 0.4 (m)