Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 31014
Modeling Directional Thermal Radiance Anisotropy for Urban Canopy

Authors: Limin Zhao, Xingfa Gu, C. Tao Yu


one of the significant factors for improving the accuracy of Land Surface Temperature (LST) retrieval is the correct understanding of the directional anisotropy for thermal radiance. In this paper, the multiple scattering effect between heterogeneous non-isothermal surfaces is described rigorously according to the concept of configuration factor, based on which a directional thermal radiance model is built, and the directional radiant character for urban canopy is analyzed. The model is applied to a simple urban canopy with row structure to simulate the change of Directional Brightness Temperature (DBT). The results show that the DBT is aggrandized because of the multiple scattering effects, whereas the change range of DBT is smoothed. The temperature difference, spatial distribution, emissivity of the components can all lead to the change of DBT. The “hot spot" phenomenon occurs when the proportion of high temperature component in the vision field came to a head. On the other hand, the “cool spot" phenomena occur when low temperature proportion came to the head. The “spot" effect disappears only when the proportion of every component keeps invariability. The model built in this paper can be used for the study of directional effect on emissivity, the LST retrieval over urban areas and the adjacency effect of thermal remote sensing pixels.

Keywords: urban canopy, Directional thermal radiance, multiple scattering, configuration factor, hot spot effect

Digital Object Identifier (DOI):

Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 1302


[1] F. Becker and Z. Li, "Surface temperature and emissivity at various scales: Definition, measurement and related problems," Remote Sensing Reviews, vol. 12, pp. 225-253, 1995.
[2] Z. Qin and A. Karnieli, "Progress in the remote sensing of land surface temperature and ground emissivity using NOAA-AVHRR data," International Journal of Remote Sensing, vol. 20, pp. 2367-2393, 1999.
[3] P. Dash, F. Göttsche, F. Olesen and F. Fischer, "Land surface temperature and emissivity estimation from passive sensor data: theory and practice-current trends," International Journal of Remote Sensing, vol. 23, pp. 2563-2594, 2002.
[4] J. P. Lagouarde and M. Irvine, "Directional anisotropy in thermal infrared measurements over Toulouse city centre during the CAPITOUL measurement campaigns: First results," Meteoro. Atmos. Phys., vol. 102, pp. 173-185, 2008.
[5] J. A. Voogt and T. R. Oke, "Effects of urban surface geometry on remotely-sensed surface temperature," International Journal of Remote Sensing, vol. 19, pp. 895-890, 1998.
[6] X. Li and A. H. Strahler, "Modeling the gap probability of a discontinuous vegetation canopy," IEEE Transactions on Geoscience and Remote Sensing, vol. 26, pp. 161-170, 1988.
[7] G. Yan, L. Jiang, J. Wang, L. Chen and X. Li, "Thermal bidirectional gap probability model for row crop canopies and validation," Science in China Series D: Earth Sciences, vol. 46, pp. 1241-1249, 2003.
[8] L. Chen, Z. Li, Q. Liu and S. Chen, "Definition of component effective emissivity for heterogeneous and non-isothermal surface and its approximate caculation," International Journal of Remote Sensing, vol. 25, pp. 231-244, 2004.
[9] T. YU, X. GU, G. Tian, M. Legrand, F. Baret, J. Hanocq, et al.,"Modeling directional brightness temperature over a maize canopy in row structure," IEEE transactions on geoscience and remote sensing, vol. 42, pp. 2290-2304, 2004.
[10] C. Fran├ºois, C. Ottlé and L. Prévot, "Analytical parameterization of canopy directional emissivity and directional radiance in the thermal infrared. Application on the retrieval of soil and foliage temperatures using two directional measurements," International Journal of Remote Sensing, vol. 18, pp. 2587-2621, 1997.
[11] Q. Liu, H. Huang and W. Qin, "An extended 3-D radiosity-graphics combined model for studying thermal-emission directionality of crop canopy," IEEE transactions on geoscience and remote sensing, vol. 45, pp. 2900-2918, 2007.
[12] A. Soux, J. A. Voogt, and T. R. Oke, "A model to calculate what a remote sensor ÔÇÿsees-of an urban surface," Boundary-Layer Meteorology, vol. 111, pp. 109-132, 2004.
[13] J. P. Gastellu-Etchegorry, E. Martin and F. Gascon , "DART: A 3-D model for simulating satellite images and surface radiation budget," International Journal of Remote Sensing, vol. 25, pp. 75-96, 2004.
[14] E. S. Krayenhoff and J. A. Voogt, "A microscale three-dimensional urban energy balance model for studying surface temperatures," Boundary-Layer Meteorology, vol. 123, pp. 433-461, 2007.
[15] T. Poglio, S. Mathieu-Marni, T. Ranchin, E. Savaria and L. Wald, "OSIrIS: a physically based simulation tool to improve training in thermal infrared remote sensing over urban areas at high spatial resolution," Remote Sensing of Environment, vol. 104, pp. 238-246, 2006.
[16] J. A. Voogt, "Assessment of an Urban Sensor View Model for thermal anisotropy," Remote Sensing of Environment, vol. 112, pp. 482-495, 2008.
[17] J. P. Lagouarde, A. Hénon, B. Kurz, P. Moreau, M. Irvine, J. Voogt, et al., "Modelling daytime thermal infrared directional anisotropy over Toulouse city centre," Remote Sensing of Environment, vol. 114, pp. 87-105, 2010.
[18] J. Sheng, J. P. Wilson and S. Lee, "Comparison of land surface temperature (LST) modeled with a spatially-distributed solar radiation model (SRAD) and remote sensing data," Environmental Modelling & Software, vol. 24, pp. 436-443, 2009.
[19] J. A. Sobrino, J. C. Jiménez-Mu├▒oz and W. Verhoef, "Canopy directional emissivity: Comparison between models," Remote Sensing of Environment, vol. 99, pp. 304-314, 2005.
[20] M. Menenti, L. Jia and Z. Li, "Multi-angular thermal infrared observations of terrestrial vegetation," in Advances in Land Remote Sensing: System, Modeling, Inversion and Application, S. Liang, Ed., ed Berlin: Springer, 2008, pp. 51-93.
[21] A. J. Prata, "A new long-wave formula for estimating downward clear-sky radiation at the surface," Quarterly Journal of the Royal Meteorological Society, vol. 122, pp. 1127-1151, 1996.
[22] S. Niemelä, P. Räisänen and H. Savijärvi, "Comparison of surface radiative flux parameterizations: Part I: Longwave radiation," Atmospheric Research, vol. 58, pp. 1-18, 2001.
[23] M. G. Iziomon, H. Mayer and A. Matzarakis, "Downward atmospheric longwave irradiance under clear and cloudy skies: Measurement and parameterization," Journal of Atmospheric and Solar-Terrestrial Physics, vol. 65, pp. 1107-1116, 2003.