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How atmospheric turbulence affects measurements of surface temperature from space

hal.structure.identifierInteractions Sol Plante Atmosphère [UMR ISPA]
dc.contributor.authorLAGOUARDE, Jean-Pierre
hal.structure.identifierInteractions Sol Plante Atmosphère [UMR ISPA]
dc.contributor.authorIRVINE, Mark Rankin
hal.structure.identifierInteractions Sol Plante Atmosphère [UMR ISPA]
dc.contributor.authorDUPONT, Sylvain
dc.date.accessioned2024-04-08T11:55:43Z
dc.date.available2024-04-08T11:55:43Z
dc.date.issued2014
dc.date.conference2014-09-22
dc.identifier.urihttps://oskar-bordeaux.fr/handle/20.500.12278/195694
dc.description.abstractEnSurface temperatures (Ts) display temporal fluctuations due to micrometeorological field variability, leading to potentially significant errors on instantaneous satellite measurements in the thermal infrared (TIR). Most models deriving fluxes from surface temperature assume stationary conditions over time steps ranging from 15 to 30 minutes. The retrieval of such fluxes is therefore prone to errors induced by the departure between the instantaneous measurements of Ts measured from space and their average value <Ts> over the model time step. The main turbulent structures present in the surface (SBL) and planetary (PBL) boundary-layers influence the temporal fluctuation intensity of Ts according to their spatial and temporal scales. Hence, high frequency turbulent structures within the SBL, corresponding to a few meters, are likely to be averaged by TIR sensors with pixels of a few tens of meters (50-100 m) such as those proposed for HyspIRI or THIRSTY (Hook et al., 2014) missions currently being defined. On the other hand, low frequency turbulent structures within the PBL, corresponding to a few hundreds of meters, exceed the pixel size of high spatial resolution TIR sensors and thus may induce significant temperature variations, in amplitude and duration. We focus on the important -but generally ignored- problem of uncertainty in the Ts measurement resulting from the surface turbulence of the atmospheric flow and its relation with the spatial resolution of TIR sensors. We present several experimental studies performed over different surfaces (pine forest, maize, bare soil) using TIR cameras either ground based or helicopter borne, designed to evaluate (i) how the spatial resolution operates a smoothing of the temporal fluctuations of the surface temperature measurements from space, and (ii) the resulting uncertainty on these measurements. Additionally, a simulation of instantaneous surface temperatures of a Maritime pine stand of 3×3 km size, performed using a Large Eddy Simulation (LES) airflow model coupled with a canopy model (MuSICA), is presented. A comparison between field measurements and numerical simulations is made using the classical assumption of frozen turbulence. The results confirm that the impact of the SBL turbulence rapidly vanishes with spatial resolution in the range between 50 and 100 m, Ts fluctuations are primarily governed by the low frequency PBL turbulence. For these resolutions, it is shown that the resulting uncertainty on Ts lies within a +/- 1 K interval. The implications for designing the specifications of future high spatial resolution TIR missions, in particular NeDT and revisit, are thereafter discussed.
dc.language.isoen
dc.title.enHow atmospheric turbulence affects measurements of surface temperature from space
dc.typeActes de congrès/Proceedings
dc.subject.halSciences de l'environnement/Milieux et Changements globaux
dc.subject.halSciences de l'ingénieur [physics]/Traitement du signal et de l'image
dc.subject.halPlanète et Univers [physics]/Sciences de la Terre/Climatologie
bordeaux.hal.laboratoriesInteractions Soil Plant Atmosphere (ISPA) - UMR 1391*
bordeaux.institutionBordeaux Sciences Agro
bordeaux.institutionINRAE
bordeaux.conference.titleRAQRS'IV, 4th International Symposium on Recent Advances in Quantitative Remote Sensing
bordeaux.countryES
bordeaux.conference.cityValencia
bordeaux.peerReviewedoui
hal.identifierhal-02795835
hal.version1
hal.conference.end2014-09-26
hal.popularnon
hal.audienceInternationale
hal.origin.linkhttps://hal.archives-ouvertes.fr//hal-02795835v1
bordeaux.COinSctx_ver=Z39.88-2004&amp;rft_val_fmt=info:ofi/fmt:kev:mtx:journal&amp;rft.date=2014&amp;rft.au=LAGOUARDE,%20Jean-Pierre&amp;IRVINE,%20Mark%20Rankin&amp;DUPONT,%20Sylvain&amp;rft.genre=unknown


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