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The storage heat flux (ΔQ S) is the net flow of heat stored within a volume that may include the air, trees, buildings and ground. Given the difficulty of measurement of this important and large flux in urban areas, we explore the use of Earth Observation (EO) data. EO surface temperatures are used with ground-based meteorological forcing, urban morphology, land cover and land use information to estimate spatial variations of ΔQ S in urban areas using the Element Surface Temperature Method (ESTM). First, we evaluate ESTM for four "simpler" surfaces. These have good agreement with observed values. ESTM coupled to SUEWS (an urban land surface model) is applied to three European cities (Basel, Heraklion, London), allowing EO data to enhance the exploration of the spatial variability in ΔQ S. The impervious surfaces (paved and buildings) contribute most to ΔQ S. Building wall area seems to explain variation of ΔQ S most consistently. As the paved fraction increases up to 0.4, there is a clear increase in ΔQ S. With a larger paved fraction, the fraction of buildings and wall area is lower which reduces the high values of ΔQ S .

[1] Aerosol and cloud studies were carried out with a polarimetric bistatic lidar setup at the Arctic Lidar Observatory for Middle Atmosphere Research (ALOMAR) in Andenes (69°N, 16E°), Norway. The measurements were performed from 10 to 23 October 2006 and covered altitudes between 1.5 and 11 km, corresponding to scattering angles between 130 and 170°. The degree of linear polarization, P L , calculated from the experiments was compared with light scattering calculations using Lorenz-Mie theory for spherical particles, the T-matrix approach for nonspherical rotationally symmetric particles, and a geometric optics ray-tracing method. Average P L values between 0.61 and 0.72 were obtained for the background aerosol under cloud-free conditions. The aerosol results may be qualitatively reproduced by standard aerosol types if a suitable combination of coarse-and fine-mode spherical particles is assumed. The P L values obtained for thin and mildly opaque clouds were in the range from 0.21 to 0.38. These results were not well described by spherical particles, and the results for relatively small prolate and oblate particles studied with the T-matrix method tended to be slightly higher than the experimental values. Geometric optics calculations for hexagonal column ice particles with surface roughness were able to reproduce the experimental cloud data. This does not rule out contributions from other types of particles, and particle orientation effects may also have influenced the results. We conclude that the experimental results are consistent with earlier in situ studies of cirrus clouds, and the further development and application of the bistatic lidar technique is discussed.