Search results for "LAND SURFACE TEMPERATURE"

Accuracy of ASTER Level-2 thermal-infrared Standard Products of an agricultural area in Spain

2007

Abstract The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) collects five-channel thermal-infrared images that are calibrated, corrected for atmospheric effects, and then converted to land surface temperature and emissivity products by the ASTER Temperature/Emissivity Separation (TES) algorithm. TES scales low- and high-contrast surfaces differently, and has been validated over water (low contrast) and rock (high contrast). Performance of TES over agricultural areas, however, has not been evaluated specifically. To address this issue, field measurements of “ground truth” were made over bare soil in addition to green grass, alfalfa and corn, at an agricultural researc…

Thermal remote sensing of land surface temperature from satellites: Current status and future prospects

1995

Abstract In this paper we review the current status for deriving land surface temperatures (LSTs) by remote sensing from satellites in the thermal infrared. Because of its widespread use and global applicability, we concentrate on the Advanced Very High Resolution Radiometer (AVHRR). The theoretical framework and methodologies used to derive LSTs are reviewed and amplified. Practical algorithms are described and their accuracy and application critically evaluated through sensitivity studies and by inter‐comparison. The important effects of the atmosphere, surface emissivity and instrument noise are considered and the current practice for removing these effects is specified. The accuracy cur…

On the atmospheric dependence of the split-window equation for land surface temperature

1994

Abstract A split-window equation is derived for land surface temperature, yielding T = T4 + A(T4 − T5) + B(e), where T is the true surface temperature, T4 and T5 are the brightness temperatures measured in AVHRR channels 4 and 5, A is a coefficient related to the atmospheric transmittances in AVHRR channels 4 and 5, being dependent on the atmosphere type and independent on surface emissivity, and B(e) takes into account the emissivity effect, which depends on both the channel surface emissivities (e4 and e5) and the atmosphere type. The atmospheric dependence of split-window coefficients, A and B(e), is discussed by means of satellite measurements simulations and in situ data. It is shown t…

Correction to “A generalized single-channel method for retrieving land surface temperature from remote sensing data” by Juan C. Jiménez-Muñoz and Jos…

2004

Evaluation of Surface Temperature and Emissivity Derived from ASTER Data: A Case Study Using Ground-Based Measurements at a Volcanic Site

2010

Abstract The land surface temperature (LST) and emissivity (LSE) derived from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data were evaluated in a low spectral contrast volcanic site at an altitude of 2000 m on the island of Tenerife, Spain. The test site is almost flat, thermally homogeneous, and without vegetation cover or variation in its surface composition. ASTER data correspond to six scenes, under both day- and nighttime conditions during 2008. This case study analyzes the impacts of the sources of inaccuracies using the temperature–emissivity separation (TES) algorithm. Uncertainties associated with inaccurate atmospheric correction were minimized by means…

Temperature and Emissivity Separation From MSG/SEVIRI Data

2014

In this paper, we analyze the feasibility of applying the temperature and emissivity separation (TES) algorithm to thermal-infrared data acquired with three bands of the Spinning Enhanced Visible and Infrared Imager (SEVIRI) onboard the Meteosat Second Generation platform (SEVTES). The performance of the SEVTES algorithm was tested using data simulated over different atmospheric conditions and surface emissivities, with errors around 1.5% for emissivity and 1.5 K for temperature when atmospheric correction is accurate enough. In contrast, errors on land-leaving radiances higher than 2% or uncertainties on total atmospheric water vapor amount higher than 5% lead to errors on emissivity highe…

Evidence of low land surface thermal infrared emissivity in the presence of dry vegetation

2007

International audience; Land surface emissivity in the thermal infrared usually increases when the vegetation amount increases, reaching values that are larger than 0.98. During an experiment in Morocco over dry barley crops, it was found that emissivity may be significantly lower than 0.98 at full cover and that in some situations, it might decrease with increasing amount of vegetation, which was unexpected. Older data acquired in Barrax, Spain, over senescent barley also exhibited emissivity values lower than 0.98. The decrease of emissivity was also observed by means of Simulations done with our land surface emissivity model developed earlier. The main reason for such behavior might be f…

On the relationship between the sky view factor and the land surface temperature derived by Landsat-8 images in Bari, Italy

2015

This study investigates the impact of landscape composition and urban morphology on land surface temperature LST in the city of Bari, Italy. For this purpose, correlation between sky view factor SVF and LST was done assigning weights to the output results and moreover expressing the latter according to the four main surface classes of the Corine land cover CLC classification method. To do this, several daytime Landsat 8 and night-time Landsat 7 ETM+ images acquired during different months of the year were used to retrieve LST by using the radiative transfer equation. The results show a positive relationship between LST and SVF, and this trend is emphasized particularly in the more dense urb…

Permanent Stations for Calibration/Validation of Thermal Sensors over Spain

2016

The Global Change Unit (GCU) at the University of Valencia has been involved in several calibration/validation (cal/val) activities carried out in dedicated field campaigns organized by ESA and other organisms. However, permanent stations are required in order to ensure a long-term and continuous calibration of on-orbit sensors. In the framework of the CEOS-Spain project, the GCU has managed the set-up and launch of experimental sites in Spain for the calibration of thermal infrared sensors and the validation of Land Surface Temperature (LST) products derived from those data. Currently, three sites have been identified and equipped: the agricultural area of Barrax (39.05 N, 2.1 W), the mars…

Modelling bulk surface resistance by MODIS data and assessment of MOD16A2 evapotranspiration product in an irrigation district of Southern Italy

2016

Abstract In this study, accurate estimates of daily actual evapotranspiration, ET a , were obtained based on the direct Penman–Monteith application, in which the bulk surface resistance term was computed by considering, as main input, daily remotely sensed Land Surface Temperature (LST). In particular, Eddy Covariance measurements of ET a , associated to LST obtained by MODIS time series (MOD11A2) characterized by 8-day resolution, allowed to calibrate a simple bulk surface resistance model, based on two-years of data observations collected in a quite homogeneous irrigation district of Sicily, where olive grove is the main crop. The model was then validated by an independent database collec…