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Calibration of DART Radiative Transfer Model with Satellite Images for Simulating Albedo and Thermal Irradiance Images and 3D Radiative Budget of Urban Environment

Landier, Lucas and Lauret, N. and Gastellu-Etchegorry, Jean-Philippe and Al Bitar, Ahmad and Mitraka, Zina and Feigenwinter, Christian and Parlow, Eberhard and Heldens, Wieke and Kotthaus, Simone and Grimmond, Sue and Lindberg, Fredrik and Chrysoulakis, Nektarios (2016) Calibration of DART Radiative Transfer Model with Satellite Images for Simulating Albedo and Thermal Irradiance Images and 3D Radiative Budget of Urban Environment. In: Proceedings of the 36th EARSEL Symposium, pp. 120-121. 36th EARSeL Symposium, 20-24 June 2016, Bonn, Germany.

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Remote sensing is increasingly used for managing urban environment. In this context, the H2020 project URBANFLUXES aims to improve our knowledge on urban anthropogenic heat fluxes, with the specific study of three cities: London, Basel and Heraklion. Usually, one expects to derive directly 2 major urban parameters from remote sensing: the albedo and thermal irradiance. However, the determination of these two parameters is seriously hampered by complexity of urban architecture. For example, urban reflectance and brightness temperature are far from isotropic and are spatially heterogeneous. Hence, radiative transfer models that consider the complexity of urban architecture when simulating remote sensing signals are essential tools. Even for these sophisticated models, there is a major constraint for an operational use of remote sensing: the complex 3D distribution of optical properties and temperatures in urban environments. Here, the work is conducted with the DART (Discrete Anisotropic Radiative Transfer) model. It is a comprehensive physically based 3D radiative transfer model that simulates optical signals at the entrance of imaging spectro-radiometers and LiDAR scanners on board of satellites and airplanes, as well as the 3D radiative budget, of urban and natural landscapes for any experimental (atmosphere, topography,…) and instrumental (sensor altitude, spatial resolution, UV to thermal infrared,…) configuration. Paul Sabatier University distributes free licenses for research activities. This paper presents the calibration of DART model with high spatial resolution satellite images (Landsat 8, Sentinel 2, etc.) that are acquired in the visible (VIS) / near infrared (NIR) domain and in the thermal infrared (TIR) domain. Here, the work is conducted with an atmospherically corrected Landsat 8 image and Bale city, with its urban database. The calibration approach in the VIS/IR domain encompasses 5 steps for computing the 2D distribution (image) of urban albedo at satellite spatial resolution. (1) DART simulation of satellite image at very high spatial resolution (e.g., 50cm) per satellite spectral band. Atmosphere conditions are specific to the satellite image acquisition. (2) Spatial resampling of DART image at the coarser spatial resolution of the available satellite image, per spectral band. (3) Iterative derivation of the urban surfaces (roofs, walls, streets, vegetation,…) optical properties as derived from pixel-wise comparison of DART and satellite images, independently per spectral band. (4) Computation of the band albedo image of the city, per spectral band. (5) Computation of the image of the city albedo and VIS/NIR exitance, as an integral over all satellite spectral bands. In order to get a time series of albedo and VIS/NIR exitance, even in the absence of satellite images, ECMWF information about local irradiance and atmosphere conditions are used. A similar approach is used for calculating the city thermal exitance using satellite images acquired in the thermal infrared domain. Finally, DART simulations that are conducted with the optical properties derived from remote sensing images give also the 3D radiative budget of the city at any date including the date of the satellite image acquisition.

Item URL in elib:https://elib.dlr.de/107764/
Document Type:Conference or Workshop Item (Speech)
Title:Calibration of DART Radiative Transfer Model with Satellite Images for Simulating Albedo and Thermal Irradiance Images and 3D Radiative Budget of Urban Environment
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Landier, LucascesbioUNSPECIFIED
Lauret, N.cesbioUNSPECIFIED
Gastellu-Etchegorry, Jean-PhilippecesbioUNSPECIFIED
Al Bitar, AhmadcesbioUNSPECIFIED
Mitraka, ZinaforthUNSPECIFIED
Feigenwinter, Christianuniversity of basel, basel, switzerlandUNSPECIFIED
Parlow, Eberharduniversity of basel, basel, switzerlandUNSPECIFIED
Heldens, WiekeWieke.Heldens (at) dlr.deUNSPECIFIED
Kotthaus, Simoneuniversity of readingUNSPECIFIED
Grimmond, Sueuniversity of readingUNSPECIFIED
Lindberg, Fredrikgötheborg universityUNSPECIFIED
Chrysoulakis, Nektariosfoundation for research and technology - hellas (forth), heraklion, crete, greeceUNSPECIFIED
Journal or Publication Title:Proceedings of the 36th EARSEL Symposium
Refereed publication:No
Open Access:Yes
Gold Open Access:No
In ISI Web of Science:No
Page Range:pp. 120-121
Keywords:3D radiative budget, energy budget, Urban canopies, Albedo, Anthropogenic fluxes
Event Title:36th EARSeL Symposium
Event Location:Bonn, Germany
Event Type:international Conference
Event Dates:20-24 June 2016
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Space
HGF - Program Themes:Earth Observation
DLR - Research area:Raumfahrt
DLR - Program:R EO - Erdbeobachtung
DLR - Research theme (Project):R - Vorhaben Fernerkundung der Landoberfläche (old)
Location: Oberpfaffenhofen
Institutes and Institutions:German Remote Sensing Data Center > Land Surface
Deposited By: Heldens, Dr Wieke
Deposited On:28 Nov 2016 11:51
Last Modified:31 Jul 2019 20:04

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