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- Feigenwinter, Christian, et al.
(författare)
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Spatial Distribution of Sensible and Latent Heat Flux in the City of Basel (Switzerland)
- 2018
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Ingår i: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing. - 1939-1404 .- 2151-1535. ; 11:8 (S1), s. 2717-2723
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Tidskriftsartikel (refereegranskat)abstract
- IEEE Urban surfaces are a complex mixture of different land covers and surface materials; the relative magnitudes of the surface energy balance components therefore vary widely across a city. Eddy covariance (EC) measurements provide the best estimates of turbulent heat fluxes but are restricted to the source area. Land surface modeling with earth observation (EO) data is beneficial for extrapolation of a larger area since citywide information is possible. Turbulent sensible and latent heat fluxes are calculated by a combination of micrometeorological approaches (the aerodynamic resistance method, ARM), EO data, and GIS techniques. Input data such as land cover fractions and surface temperatures are derived from Landsat 8 OLI and TIRS, urban morphology was calculated from high-resolution digital building models and GIS data layers, and meteorological data were provided by flux tower measurements. Twenty-two Landsat scenes covering all seasons and different meteorological conditions were analyzed. Sensible heat fluxes were highest for industrial areas, railway stations, and areas with high building density, mainly corresponding to the pixels with highest surface-to-air temperature differences. The spatial distribution of latent heat flux is strongly related to the saturation deficit of vapor and the (minimum) stomatal resistance of vegetation types. Seasonal variations are highly dependent on meteorological conditions, i.e., air temperature, water vapor saturation deficit, and wind speed. Comparison of measured fluxes with modeled fluxes in the weighted source area of the flux towers is moderately accurate due to known drawbacks in the modeling approach and uncertainties inherent to EC measurements, particularly in urban areas.
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- Feigenwinter, Christian, et al.
(författare)
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Spatial distribution of sensible and latent heat flux in the URBANFLUXES case study city Basel (Switzerland)
- 2017
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Ingår i: 2017 Joint Urban Remote Sensing Event (JURSE). Dubai; United Arab Emirates; 6-8 March 2017. - 9781509058099
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Konferensbidrag (refereegranskat)abstract
- Turbulent sensible and latent heat fluxes are calculated by a combined method using micrometeorological approaches (the Aerodynamic Resistance Method ARM), Earth Observation (EO) data and GIS-Techniques. The spatial distributions of turbulent heat fluxes were analyzed for 22 for the city of Basel (Switzerland), covering all seasons and different meteorological conditions. Seasonal variations in heat fluxes are strongly dependent on meteorological conditions, i.e. air temperature, water vapor saturation deficit and wind speed. The agreement of measured fluxes (by the Eddy Covariance method) with modeled fluxes in the weighted source area of the flux towers is moderate due to known drawbacks in the modelling approach and uncertainties inherent to EC measurements, particularly also in urban areas.
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- Mitraka, Zina, et al.
(författare)
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Towards discriminating between zones with different thermal behaviour in cities
- 2017
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Ingår i: 2017 Joint Urban Remote Sensing Event, JURSE 2017. Dubai, United Arab Emirates; 6-8 March 2017.. - 9781509058082
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Konferensbidrag (refereegranskat)abstract
- The advances in satellite sensor technology, the launch of new satellites and the continuous development of remote sensing technology constantly increase the opportunities for monitoring the thermal behaviour of cities from space. Not only the surface temperature, but several other parameters related to the urban climate can be quantified from Earth Observation (EO) data. In this study, remote sensing techniques are applied to derive EO data products and a methodology is proposed that combines this information to discriminate between zones with different thermal behaviour in cities. Information on the building, pervious and paved surface cover, the surface albedo, the mean building/tree height and the sky view factor is quantified in local scale and then used to identify possible zones with homogeneous thermal characteristics.
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