Thermal-infrared spectral and angular characterization of crude oil and seawater emissivities for oil slick identification

Previous work has shown that crude oil emissivity is lower than that of seawater in the thermal-infrared (TIR) spectrum. Thus, oil slicks cause an emissivity decrease relative to seawater in that region. The aim of this paper was to carry out experimental measurements to characterize crude oil and seawater emissivity spectral and angular variations. The results showed that crude oil emissivity is lower than seawater emissivity and essentially flat in the 8 - 13 μm atmospheric window. Crude oil emissivity has a marked emissivity decrease with angle (from 0.956±0.005 at 15º to 0.873±0.007 at 65º), even higher than that of seawater, and thus the seawater-crude emissivity difference increases with angle (from +0.030±0.007 at close-to-nadir angles up to +0.068±0.010 in average at 65º). In addition, the experimental results were checked by using the dual-angle viewing capability of the ENVISAT-AATSR images (i.e., 0º-22º and 53º-55º for nadir and forward views respectively), with data acquired during the BP Deepwater Horizon oil slick in 2010. The objective was to explore the applicability to satellite observations. Nadir-forward emissivity differences of +0.028 and +0.017 were obtained for the oil slick and surrounding clean seawater respectively. Emissivity differences between the seawater and oil slick were +0.035 and +0.046 for nadir and forward views respectively, in agreement with the experimental data. The increase of seawater-crude emissivity difference with angle gives significant differences for off-nadir observation angles, showing a new chance of crude oil slick identification from satellite TIR data

Evaluation of landsat-8 thermal bands to monitor land surface temperature

Ponencia presentada en: IX Congreso de la Asociación Española de Climatología celebrado en Almería entre el 28 y el 30 de octubre de 2014.[ES]El nuevo Thermal Infrared Sensor (TIRS) a bordo del Landsat-8 (L8) dispone de dos bandas térmicas, 10 (11.60-11.19 μm) y 11 (11.50-12.51 μm), con una resolución espacial de 100m, con el fin de proporcionar temperaturas de la superficie terrestre (LST) de una manera más precisa que su predecesor Landsat-7 ETM+. El L8 fue lanzado en febrero de 2013, comenzando su adquisición operativa a mediados de abril. Los primeros estudios realizados por el equipo de calibración de L8 mostraron errores sistemáticos significativos para el TIRS, y en febrero de 2014 el archivo de imágenes L8 TIRS fue reprocesado para corregir dichos errores. En este estudio, con el fin de comprobar la calibración del L8 TIRS, realizamos medidas de campo en una zona llana y térmicamente homogénea dedicada al cultivo del arroz. A partir de estas medidas de LST simulamos las radiancias y temperaturas de brillo a nivel del satélite y las comparamos con los datos TIRS. Tal y como apuntaba el equipo de L8, nuestros resultados muestran una sobreestimación para la banda 11. Sin embargo, el recalibrado aplicado por dicho equipo para ambas bandas ha resultado no ser satisfactorio en nuestra zona experimental, ya que proponen sustraer errores sistemáticos mayores a los requeridos.[EN]The new Landsat-8 (L8) Thermal Infrared Sensor (TIRS) has two thermal bands, 10 (11.60- 11.19 μm) and 11 (11.50-12.51 μm) at 100-m spatial resolution, aimed to provide more accurate Land Surface Temperatures (LST) than Landsat-7 ETM+. L8 was launched on February 2013, and operational acquisitions started in middle April 2013. The first studies by the L8 Calibration Team showed significant TIRS temperature offsets, and in February 2014 the L8 TIRS archive was reprocessed to remove these offsets. In this study, ground LST measurements were performed in a flat and thermally homogeneous area of rice-crop fields for checking the calibration of the L8 TIRS bands. At-sensor radiances and brightness temperatures were simulated from ground-measured LSTs and compared with TIRS values. A significant overestimation was observed for band 11, in agreement with the L8 Calibration Team results. However, their recalibration was shown unsatisfactory in our test site for both bands, since they proposed subtracting higher offsets than required.This study was supported by the Spanish Ministerio de Economía y Competitividad (projects CGL2010-16364, CGL2010-17577/CLI, CGL2011-13579-E, CGL2011-30433 and GRACCIE Consolider-Ingenio 2010; and Dr. Niclòs "Ramón y Cajal" Research Contract) and Generalitat Valenciana (PROMETEO/2009/006 and PROMETEO/2009/086 projects)

The use of lasers for hydrographic studies

The utilization of remote laser sensors in water pollution detection and identification, coastal environmental monitoring, and bathymetric depth sounding, is discussed. q

Earth resources: A continuing bibliography with indexes (issue 58)

This bibliography lists 500 reports, articles, and other documents introduced into the NASA scientific and technical information system between April 1 and June 30, 1988. Emphasis is placed on the use of remote sensing and geophysical instrumentation in spacecraft and aircraft to survey and inventory natural resources and urban areas. Subject matter is grouped according to agriculture and forestry, environmental changes and cultural resources, geodesy and cartography, geology and mineral resources, hydrology and water management, data processing and distribution systems, instrumentation and sensors, and economic analysis

Literature review of the remote sensing of natural resources

Abstracts of 596 documents related to remote sensors or the remote sensing of natural resources by satellite, aircraft, or ground-based stations are presented. Topics covered include general theory, geology and hydrology, agriculture and forestry, marine sciences, urban land use, and instrumentation. Recent documents not yet cited in any of the seven information sources used for the compilation are summarized. An author/key word index is provided

Earth Resources: A continuing bibliography with indexes (Issue 37)

This bibliography lists 512 reports, articles, and other documents introduced into the NASA scientific and technical information system between January 1 and March 31, 1983. Emphasis is placed on the use of remote sensing and geophysical instrumentation in spacecraft and aircraft to survey and inventory natural resources and urban areas. Subject matter is grouped according to agriculture and forestry, environmental changes and cultural resources, geodesy and cartography, geology and mineral resources, hydrology and water management, data processing and distribution systems, instrumentation and sensors, and economic analysis

Remote Sensing of Earth Resources: A literature survey with indexes (1970 - 1973 supplement). Section 1: Abstracts

Abstracts of reports, articles, and other documents introduced into the NASA scientific and technical information system between March 1970 and December 1973 are presented in the following areas: agriculture and forestry, environmental changes and cultural resources, geodesy and cartography, geology and mineral resources, oceanography and marine resources, hydrology and water management, data processing and distribution systems, instrumentation and sensors, and economic analysis

Generación y Validación de algoritmos para la obtención de la temperatura de la superficie terrestre utilizando técnicas de Teledetección en el infrarrojo térmico

La temperatura de superficie terrestre, LST (por sus siglas en inglés), es uno de los principales parámetros en el estudio de balance energético y de masa entre la atmosfera y el suelo, en particular, en la estimación de la evapotranspiración y el estrés hídrico que pueda sufrir la vegetación (Hall et al, 1992; Sellers, et al., 1995; Anderson, et al., 1997; Sánchez, et al. 2008). Además, la LST es necesaria como dato inicial en modelos de predicción meteorológica (Barton, et al. 1989; Gouturbe, et al. 1993), evaluación de daños provocados por las heladas (Caselles y Sobrino 1989), y detección de incendios forestales (Calle, et al. 2005), entre otros muchos. La LST puede considerarse también como indicador del cambio climático (Allen, et al. 1994) y de la desertificación de una zona (Lambin y Ehrlich 1997). La teledetección en el infrarrojo térmico es la forma más factible de obtener esta magnitud para grandes extensiones terrestres bajo diferentes resoluciones espaciales y periodicidades. El problema fundamental de la medida de la LST a partir de datos de satélite es la necesidad de corregir estos datos de los efectos debidos a la absorción de la atmósfera y a la emisividad de la superficie. La principal contribución a la absorción de la atmósfera en el intervalo del infrarrojo térmico es debida al vapor de agua contenido en ella. Esta absorción es difícil de considerar, ya que la distribución del vapor de agua en la atmósfera es muy variable. Esto hace necesario conocer bien la estructura de la atmósfera (bien a través de radiosondeos, productos derivados de sensores a bordo de satélites o de reanálisis) sobre la superficie en la que deseamos calcular la temperatura, para así corregir atmosféricamente, utilizando modelos de transferencia radiativa, la temperatura de la superficie medida desde satélite. Para la corrección de los efectos de la emisividad en superficies terrestres, la problemática reside en la heterogeneidad que poseen. Es necesario un buen conocimiento de la emisividad de la superficie y de su variación, tanto espectral como espacial y angular, para corregir los efectos de ésta en la medida de temperatura de la superficie desde satélite. Los métodos de corrección atmosférica y emisividad más sencillos y operativos son los basados en la absorción diferencial (McMillin 1975). Este principio se basa en la utilización de dos medidas de la misma superficie realizadas en diferentes condiciones de observación. La corrección atmosférica se obtiene a partir de la diferente absorción atmosférica que existe bajo dichas condiciones. Éstas pueden ser: una misma superficie observada en dos bandas espectrales centradas en la ventana atmosférica 10,5 m -12,5 m, split-window (Prabhakara et al., 1974; Deschamps y Phulpin 1980) o bien bajo dos ángulos de observación distintos, dual-angle (Saunders 1970). La principal ventaja de estas técnicas es el hecho de que no es necesaria la caracterización de la atmósfera ni el uso de modelos de transferencia radiativa para corregir las medidas realizadas en el infrarrojo térmico. Los métodos de absorción diferencial fueron inicialmente aplicados para la obtención de la temperatura de la superficie del mar (SST por sus siglas en ingles). Ésta posee una emisividad que es bien conocida y una gran homogeneidad, lo que provoca que dichos algoritmos funcionen muy bien en este tipo de superficie. Más tarde estas técnicas fueron aplicadas a la obtención de la temperatura de la superficie terrestre, LST, teniendo en cuenta los efectos de la emisividad de la superficie (Becker y Li 1990; Prata 1994; Wan y Dozier 1996; Coll y Caselles 1997) para lo que se requiere un buen conocimiento de las características de la superficie a través de su emisividad y las variaciones espectral y angular de la misma.A database of global, cloud-free, and atmospheric radiosounding profiles was compiled with the aim of simulating radiometric measurements from satellite-borne sensors in the thermal infrared. The objective of the simulated data is to generate split-window (SW) and dual-angle (DA) algorithms for the retrieval of land surface temperature (LST) from Terra/Moderate Resolution Imaging Spectroradiometer (MODIS), Envisat/Advanced Along Track Scanning Radiometer (AATSR) data and Meteosat Second Generation/Spinning Enhanced Visible and Infrared Imager (SEVIRI). The database contains 382 radiosounding profiles acquired over land, with nearly uniform distribution of precipitable water between 0.02 and 5.5 cm. Radiative transfer calculations were performed with the MODTRAN 4 code for viewing angles between 0◦ and 65◦. The resulting radiance spectra were convoluted with the response filter functions of EOS/MODIS bands 31 and 32, Envisat/AATSR channels at 11 and 12 μm and MSG/SEVIRI channels 9 and 10. By using the simulation database, the SW algorithms adapted for EOS/MODIS, Envisat/AATSR and MSG/SEVIRI data and the DA algorithms for Envisat/AATSR data were developed. Algorithms are quadratic in the brightness temperature difference and depend explicitly on the land surface emissivity. Lineal dependence with sec()-1 were showed in atmospheric coefficients in the SEVIRI case. The products of LST and the algorithms were compared with ground LST measurements in the conventional temperature-based (T-based) method in several sites located close to the city of Valencia, Spain, in a large, flat, and thermally homogeneous area of rice crops, Lake Tahoe CA/NV (USA) and an high-plain, homogeneous area of shrubland. We also validated those by using an alternative radiance-based (R-based) method with ground LSTs calculated from 11 m channel brightness temperatures through radiative transfer simulations using atmospheric temperature and water vapor profiles together with surface emissivity data. Both validation methods showed similar results in all cases. The results obtained have no bias and a standard deviation around ±0.5 K for the SW algorithms at nadir for Envisat/AATSR and EOS/MODIS and ± 1.1 K in MSG/SEVIRI. The SW algorithm used in the forward view results in a bias of 0.6 K and a standard deviation of ±0.8 K. The worst results are obtained in the other algorithms with a bias close to −1.0 K and a standard deviation close to ±1.1 K in the case of the DA algorithms

Air-Water Gas Transfer

A more complete understanding of the mechanisms involved in the exchange of gases between the atmosphere and the sea is needed if we are to address various environmental issues, and is essential to improved modeling of global climate. This volume contains selected papers from the Third International Symposium on Air-Water Gas Transfer, held at the University of Heidelberg, in Heidelberg, Germany from July 24-27, 1995. The papers are arranged into seven parts: Physical and Chemical Mechanisms, Waves and Turbulence, Breaking Waves and Bubbles, Measuring Technology, Laboratory Measurements and Facilities, Field Measurements, Remote Sensing, and Global Modeling. Emphasis is given to the transfer of carbon dioxide and other radiatively important gases, reflecting current interest in potential global warming. Breaking waves and the bubbles thereby generated play a prominent role in that regard. Also featured are non-invasive measurement technologies, many of which lend themselves to remote sensing applications. Those interested in chemical engineering, fluid mechanics, hydrology, hydraulics, environmental engineering, water quality engineering, climatology, meteorology, and oceanography will find this work a valuable resource

Abstracts on Radio Direction Finding (1899 - 1995)

The files on this record represent the various databases that originally composed the CD-ROM issue of "Abstracts on Radio Direction Finding" database, which is now part of the Dudley Knox Library's Abstracts and Selected Full Text Documents on Radio Direction Finding (1899 - 1995) Collection. (See Calhoun record https://calhoun.nps.edu/handle/10945/57364 for further information on this collection and the bibliography). Due to issues of technological obsolescence preventing current and future audiences from accessing the bibliography, DKL exported and converted into the three files on this record the various databases contained in the CD-ROM. The contents of these files are: 1) RDFA_CompleteBibliography_xls.zip [RDFA_CompleteBibliography.xls: Metadata for the complete bibliography, in Excel 97-2003 Workbook format; RDFA_Glossary.xls: Glossary of terms, in Excel 97-2003 Workbookformat; RDFA_Biographies.xls: Biographies of leading figures, in Excel 97-2003 Workbook format]; 2) RDFA_CompleteBibliography_csv.zip [RDFA_CompleteBibliography.TXT: Metadata for the complete bibliography, in CSV format; RDFA_Glossary.TXT: Glossary of terms, in CSV format; RDFA_Biographies.TXT: Biographies of leading figures, in CSV format]; 3) RDFA_CompleteBibliography.pdf: A human readable display of the bibliographic data, as a means of double-checking any possible deviations due to conversion