scholarly journals Multiscale thermal-infrared measurements of the Mauna Loa caldera, Hawaii

2001 ◽  
Author(s):  
Lee K. Balick ◽  
Alan R. Gillespie ◽  
Elsa Abbott ◽  
Donald Sabol ◽  
Anne B. Kahle ◽  
...  
Keyword(s):  
Thermal Infrared ◽  
Mauna Loa ◽  
Infrared Measurements

scholarly journals A Blackbody Design for SI-Traceable Radiometry for Earth Observation

2008 ◽  
Vol 25 (11) ◽  
pp. 2046-2054 ◽  
Author(s):  
P. Jonathan Gero ◽  
John A. Dykema ◽  
James G. Anderson
Keyword(s):  
Phase Transitions ◽  
Temperature Scale ◽  
International System ◽  
Thermal Infrared ◽  
Earth Observation ◽  
International Standards ◽  
Future Climate Change ◽  
Single Temperature ◽  
System Of Units ◽  
Infrared Measurements

Abstract Spaceborne measurements pinned to international standards are needed to monitor the earth’s climate, quantify human influence thereon, and test forecasts of future climate change. The International System of Units (SI, from the French for Système International d’Unités) provides ideal measurement standards for radiometry as they can be realized anywhere, at any time in the future. The challenge is to credibly prove on-orbit accuracy at a claimed level against these international standards. The most accurate measurements of thermal infrared spectra are achieved with blackbody-based calibration. Thus, SI-traceability is obtained through the kelvin scale, making thermometry the foundation for on-orbit SI-traceable spectral infrared measurements. Thermodynamic phase transitions are well established as reproducible temperature standards and form the basis of the international practical temperature scale (International Temperature Scale of 1990, ITS-90). Appropriate phase transitions are known in the temperature range relevant to thermal infrared earth observation (190–330 K) that can be packaged such that they are chemically stable over the lifetime of a space mission, providing robust and traceable temperature calibrations. A prototype blackbody is presented that is compact, highly emissive, thermally stable and homogeneous, and incorporates a small gallium melting point cell. Precision thermal control of the blackbody allows the phase transition to be identified to within 5 mK. Based on these results, the viability of end-to-end thermometric calibration of both single-temperature and variable-temperature blackbodies on orbit by employing multiple-phase-change cells was demonstrated.

scholarly journals Methane profiles from GOSAT thermal infrared spectra

2018 ◽  
Vol 11 (6) ◽  
pp. 3815-3828 ◽  
Author(s):  
Arno de Lange ◽  
Jochen Landgraf
Keyword(s):  
Lower Troposphere ◽  
Principal Component ◽  
Thermal Infrared ◽  
Total Carbon ◽  
Atmospheric Composition ◽  
Data Sets ◽  
Atmospheric Methane ◽  
Infrared Band ◽  
Correction Scheme ◽  
Infrared Measurements

Abstract. This paper discusses the retrieval of atmospheric methane profiles from the thermal infrared band of the Japanese Greenhouse Gases Observing Satellite (GOSAT) between 1210 and 1310 cm−1, using the RemoTeC analysis software. Approximately one degree of information on the vertical methane distribution is inferred from the measurements, with the main sensitivity at about 9 km altitude but little sensitivity to methane in the lower troposphere. For verification, we compare the GOSAT-TIR methane profile retrieval results with profiles from model fields provided by the Monitoring Atmospheric Composition and Climate (MACC) project, scaled to the total column measurements of the Total Carbon Column Observing Network (TCCON) at ground-based measurement sites. Without any radiometric corrections of GOSAT observations, differences between both data sets can be as large as 10 %. To mitigate these differences, we developed a correction scheme using a principal component analysis of spectral fit residuals and airborne observations of methane during the HIAPER pole-to-pole observations (HIPPO) campaign II and III. When the correction scheme is applied, the bias in the methane profile can be reduced to less than 2 % over the whole altitude range with respect to MACC model methane fields. Furthermore, we show that, with this correction, the retrievals result in smooth methane fields over land and ocean crossings and no differences can be discerned between daytime and nighttime measurements. Finally, a cloud filter is developed for the nighttime and ocean measurements. This filter is rooted in the GOSAT-TIR (thermal infrared) measurements and its performance, in terms of biases, is consistent with the cloud filter based on the GOSAT-SWIR (shortwave infrared) measurements. The TIR filter shows a higher acceptance rate of observations than the SWIR filter, at the cost of a higher uncertainty in the retrieved methane profiles.

scholarly journals Combining continuous spatial and temporal scales for SGD investigations using UAV-based thermal infrared measurements

2018 ◽  
Author(s):  
Ulf Mallast ◽  
Christian Siebert
Keyword(s):  
Thermal Radiation ◽  
Infrared Radiation ◽  
Thermal Infrared ◽  
Dead Sea ◽  
Flow Dynamics ◽  
Temporal Scales ◽  
Spatial And Temporal Scales ◽  
Infrared Measurements ◽  
Spatiotemporal Behavior ◽  
Aerial Vehicle

Abstract. Submarine groundwater discharge (SGD) is highly variable in spatial and temporal terms due to interplay of several terrestrial and marine processes. While discrete in-situ measurements provide a continuous temporal scale to investigate underlying processes and thus accounts for temporal heterogeneity, remotely sensed thermal infrared radiation sheds light on the spatial heterogeneity as it provides a continuous spatial scale. Here we report results of the combination of both, the continuous spatial and temporal scales, using the ability of an Unmanned Aerial Vehicle to hover above a predefined location and the continuous recording of thermal radiation of a coastal area at the Dead Sea (Israel). With a flight altitude of 65 m above the water surface resulting in a spatial resolution of 13 cm and a thermal camera (FLIRTau2) which measures the upwelling long-wave infrared radiation at 4 Hz resolution we are able to generate a time sequence of thermal radiation images which allows us to analyse spatiotemporal SGD dynamics. In turn, we are able to enhance focused SGD spots otherwise being camouflaged by strong lateral flow dynamics that may not be observed on single thermal radiation images. Plus, we show the spatiotemporal behavior of a SGD induced thermal radiation pattern to vary in size and over time by up to 55 % for focused SGDs and by up to 600 % for diffuse SGDs due to different underlying flow dynamics. These flow dynamics even display a short-term periodicity in the order of 20 to 78 s for diffuse SGD which we attribute to an interplay of conduit maturity/geometry and wave setup.

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