Radiometric Calibration Evaluation for FY3D MERSI-II Thermal Infrared Channels at Lake Qinghai

The absolute radiometric accuracy of the Fengyun 3D advanced Medium Resolution Spectral Imager (FY3D MERSI-II) thermal infrared bands was evaluated using the collected field measurements and atmospheric transfer simulations during 16–22 August 2019 at Lake Qinghai. A thermal infrared radiometer equipped on an unmanned surface vehicle was used to continuously collect the water temperature. Atmospheric conditions, surface emissivity, and aerosol optical depth measured near the field experiment site were adopted by the atmospheric transfer code to calculate the parameters about the influence of atmosphere on long-wave radiation, including the path radiance and the transmittance propagated from land surface to the satellite. The radiometric calibration accuracy analysis suggests that the differences between the simulated brightness temperature and satellite-based brightness temperature are −0.346 K and −0.722 K for channel 24 on 18 and 20 August, respectively, while it reaches −0.460 K and −1.036 K for channel 25 on 18 and 20 August, respectively. The vicarious calibration coefficients were found to be in good agreement with the internal onboard calibration coefficient in channel 24 and 25 of the FY3D MERSI-II according to the validation analysis in selected regions. The thermal infrared bands of the FY3D have a good in-orbit operational status according to our vicarious calibration experiments.

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Vicarious Radiometric Calibration of Ocean Color Bands for FY-3D/MERSI-II at Lake Qinghai, China

Sensors ◽

10.3390/s21010139 ◽

2020 ◽

Vol 21 (1) ◽

pp. 139

Author(s):

Shengli Chen ◽

Xiaobing Zheng ◽

Xin Li ◽

Wei Wei ◽

Shenda Du ◽

...

Keyword(s):

Infrared Imaging ◽

Large Deviation ◽

Ocean Color ◽

Calibration Method ◽

Surface Measurement ◽

Radiometric Calibration ◽

Lake Qinghai ◽

Vicarious Calibration ◽

Calibration Methods ◽

Spectral Imager

To calibrate the low signal response of the ocean color (OC) bands and test the stability of the Fengyun-3D (FY-3D)/Medium Resolution Spectral Imager II (MERSI-II), an absolute radiometric calibration field test of FY-3D/MERSI-II at the Lake Qinghai Radiometric Calibration Site (RCS) was carried out in August 2018. The lake surface and atmospheric parameters were mainly measured by advanced observation instruments, and the MODerate spectral resolution atmospheric TRANsmittance algorithm and computer model (MODTRAN4.0) was used to simulate the multiple scattering radiance value at the altitude of the sensor. The results showed that the relative deviations between bands 9 and 12 are within 5.0%, while the relative deviations of bands 8, and 13 are 17.1%, and 12.0%, respectively. The precision of the calibration method was verified by calibrating the Aqua/Moderate-resolution Imaging Spectroradiometer (MODIS) and National Polar-orbiting Partnership (NPP)/Visible Infrared Imaging Radiometer (VIIRS), and the deviation of the calibration results was evaluated with the results of the Dunhuang RCS calibration and lunar calibration. The results showed that the relative deviations of NPP/VIIRS were within 7.0%, and the relative deviations of Aqua/MODIS were within 4.1% from 400 nm to 600 nm. The comparisons of three on-orbit calibration methods indicated that band 8 exhibited a large attenuation after launch and the calibration results had good consistency at the other bands except for band 13. The uncertainty value of the whole calibration system was approximately 6.3%, and the uncertainty brought by the field surface measurement reached 5.4%, which might be the main reason for the relatively large deviation of band 13. This study verifies the feasibility of the vicarious calibration method at the Lake Qinghai RCS and provides the basis and reference for the subsequent on-orbit calibration of FY-3D/MERSI-II.

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Estimation of 1-km all-weather remotely sensed land surface temperature based on reconstructed spatial-seamless satellite passive microwave brightness temperature and thermal infrared data

ISPRS Journal of Photogrammetry and Remote Sensing ◽

10.1016/j.isprsjprs.2020.07.014 ◽

2020 ◽

Vol 167 ◽

pp. 321-344 ◽

Cited By ~ 3

Author(s):

Xiaodong Zhang ◽

Ji Zhou ◽

Shunlin Liang ◽

Linna Chai ◽

Dongdong Wang ◽

...

Keyword(s):

Surface Temperature ◽

Brightness Temperature ◽

Land Surface Temperature ◽

Land Surface ◽

Thermal Infrared ◽

Remotely Sensed ◽

Passive Microwave ◽

Microwave Brightness Temperature ◽

Infrared Data

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Satellite thermal infrared anomalies associated with strong earthquakes in the Vrancea area of Romania

Open Geosciences ◽

10.1515/geo-2015-0046 ◽

2015 ◽

Vol 7 (1) ◽

Cited By ~ 6

Author(s):

Maria A. Zoran ◽

Roxana S. Savastru ◽

Dan M. Savastru

Keyword(s):

Land Surface ◽

Thermal Infrared ◽

Wave Radiation ◽

Spatiotemporal Variations ◽

Outgoing Long Wave Radiation ◽

Strong Earthquakes ◽

Thermal Anomalies ◽

Noaa Avhrr ◽

Long Wave ◽

Before And After

AbstractThermal anomalies which are known to be significant precursors of strong earthquakes can be evidenced by spectral thermal infrared (TIR) bands recorded by sensors on board of NOAA-AVHRR and Terra/Aqua- MODIS satellite. In order to locate relevant thermal anomalous variations prior to some strong even moderate earthquakes recorded in Vrancea tectonic active zone in Romania, satellite derived geophysical parameters have been used: land surface temperature (LST), outgoing long-wave radiation (OLR) and mean air temperature (AT). Spatiotemporal variations of LST, OLR, and AT before and after three strong earthquakes in Vrancea area (M

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Radiometric Cross-calibration of KOMPSAT-3A with Landsat-8

ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences ◽

10.5194/isprsarchives-xli-b1-379-2016 ◽

2016 ◽

Vol XLI-B1 ◽

pp. 379-382

Author(s):

D. Y. Shin ◽

H. Y. Ahn ◽

S. G. Lee ◽

C. U. Choi ◽

J. S. Kim

Keyword(s):

Optical Quality ◽

Calibration Coefficient ◽

Spectral Radiance ◽

Color Filter ◽

Landsat 8 ◽

Radiometric Calibration ◽

Atmospheric Conditions ◽

Satellite Sensors ◽

The Cross ◽

Cross Calibration

In this study, Cross calibration was conducted at the Libya 4 PICS site on 2015 using Landsat-8 and KOMPSAT-3A. Ideally a cross calibration should be calculated for each individual scene pair because on any given date the TOA spectral profile is influenced by sun and satellite view geometry and the atmospheric conditions. However, using the near-simultaneous images minimizes this effect because the sensors are viewing the same atmosphere. For the cross calibration, the calibration coefficient was calculated by comparing the at sensor spectral radiance for the same location calculated using the Landsat-8 calibration parameters in metadata and the DN of KOMPSAT-3A for the regions of interest (ROI). Cross calibration can be conducted because the satellite sensors used for overpass have a similar bandwidth. However, not all satellites have the same color filter transmittance and sensor reactivity, even though the purpose is to observe the visible bands. Therefore, the differences in the RSR should be corrected. For the cross-calibration, a calibration coefficient was calculated using the TOA radiance and KOMPSAT-3 DN of the Landsat-8 OLI overpassed at the Libya 4 Site, As a result, the accuracy of the calibration coefficient at the site was assumed to be ± 1.0%. In terms of the results, the radiometric calibration coefficients suggested here are thought to be useful for maintaining the optical quality of the KOMPSAT-3A.

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Uncertainty Analysis for RadCalNet Instrumented Test Sites Using the Baotou Sites BTCN and BSCN as Examples

Remote Sensing ◽

10.3390/rs12111696 ◽

2020 ◽

Vol 12 (11) ◽

pp. 1696 ◽

Cited By ~ 3

Author(s):

Lingling Ma ◽

Yongguang Zhao ◽

Emma R. Woolliams ◽

Caihong Dai ◽

Ning Wang ◽

...

Keyword(s):

Uncertainty Analysis ◽

International System ◽

Uncertainty Budget ◽

In Situ Monitoring ◽

Radiometric Calibration ◽

Atmospheric Conditions ◽

Vicarious Calibration ◽

Calibration And Validation ◽

System Of Units ◽

Wide Range

Vicarious calibration and validation techniques are important tools to ensure the long-term stability and inter-sensor consistency of satellite sensors making observations in the solar-reflective spectral domain. Automated test sites, which have continuous in situ monitoring of both ground reflectance and atmospheric conditions, can greatly increase the match-up possibilities for a wide range of space agency and commercial sensors. The Baotou calibration and validation test site in China provides operational high-accuracy and high-stability vicarious calibration and validation for high spatial resolution solar-reflective remote-sensing sensors. Two sites, given the abbreviations BTCN (an artificial site) and BSCN (a natural sandy site), have been selected as reference sites for the Committee on Earth Observation Satellites radiometric calibration network (RadCalNet). RadCalNet requires sites to provide data in a consistent format but does not specify the required operational conditions for a RadCalNet site. The two Baotou sites are the only sites to date that make spectral measurements for their continuous operation. One of the core principles of RadCalNet is that each site should have a metrologically rigorous uncertainty budget which also describes the site’s traceability to the international system of units, the SI. This paper shows a formalized metrological approach to determining and documenting the uncertainty budget and traceability of a RadCalNet site. This approach follows the Guide to the Expression of Uncertainty in Measurement. The paper describes the uncertainty analysis for bottom-of-atmosphere and top-of-atmosphere reflectance in the spectral region from 400 to 1000 nm for the Baotou sites and gives preliminary results for the uncertainty propagating this to top-of-atmosphere reflectance.

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Challenges for In-Flight Calibration of Thermal Infrared Instruments for Earth Observation

Remote Sensing ◽

10.3390/rs12111832 ◽

2020 ◽

Vol 12 (11) ◽

pp. 1832

Author(s):

David Smith ◽

Daniel Peters ◽

Timothy Nightingale ◽

Jonathan Pearce ◽

Radka Veltcheva

Keyword(s):

Land Surface ◽

Direct Method ◽

Thermal Infrared ◽

Platinum Resistance Thermometer ◽

Platinum Resistance ◽

Radiometric Calibration ◽

Resistance Thermometer ◽

Infrared Wavelength ◽

Radiative Power ◽

Space Environments

Satellite instruments operating in the thermal infrared wavelength range >3 µm provide information for applications such as land surface temperature (LST), sea surface temperatures (SST), land surface emissivity, land classification, soil composition, volcanology, fire radiative power, cloud masking, aerosols, and trace gases. All these instruments are dependent on blackbody (BB) calibration sources to provide the traceability of the radiometric calibration to SI (Système International d’Unités). A key issue for flight BB sources is to maintain the traceability of the radiometric calibration from ground to orbit. For example, the temperature of the BB is measured by a number of precision thermometers that are calibrated against a reference Standard Platinum Resistance Thermometer (SPRT) to provide the traceability to the International Temperature Scale of 1990 (ITS-90). However, once calibrated the thermometer system is subject to drifts caused by on-ground testing, the launch and space environments. At best the uncertainties due to thermometer ageing can only be estimated as there is no direct method for recalibrating. Comparisons with other satellite sensors are useful for placing an upper limit on calibration drifts but do not themselves provide a traceable link to the SI. In this paper, we describe we describe some of the technology developments, including phase change cells for use as reference standards, thermometer readout electronics and implementation of novel coatings, that are in progress to enhance the traceability of flight calibration systems in the thermal infrared.

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Temperature and Emissivity Inversion Accuracy of Spectral Parameter Changes and Noise of Hyperspectral Thermal Infrared Imaging Spectrometers

Sensors ◽

10.3390/s20072109 ◽

2020 ◽

Vol 20 (7) ◽

pp. 2109 ◽

Cited By ~ 1

Author(s):

Honglan Shao ◽

Chengyu Liu ◽

Chunlai Li ◽

Jianyu Wang ◽

Feng Xie

Keyword(s):

Land Surface ◽

Infrared Imaging ◽

Quadratic Function ◽

Thermal Infrared ◽

Wavelength Shift ◽

Atmospheric Conditions ◽

Center Wavelength ◽

Spectral Parameters ◽

Thermal Infrared Imaging ◽

S Curve

The emergence of hyperspectral thermal infrared imaging spectrometers makes it possible to retrieve both the land surface temperature (LST) and the land surface emissivity (LSE) simultaneously. However, few articles focus on the problem of how the instrument’s spectral parameters and instrument noise level affect the LST and LSE inversion errors. In terms of instrument development, this article simulated three groups of hyperspectral thermal infrared data with three common spectral parameters and each group of data includes tens of millions of simulated radiances of 1525 emissivity curves with 17 center wavelength shift ratios, 6 full width at half maximum (FWHM) change ratios and 6 noise equivalent differential temperatures (NEDTs) under 15 atmospheric conditions with 6 object temperatures, inverted them by two temperature and emissivity separation methods (ISSTES and ARTEMISS), and analyzed quantitatively the effects of the spectral parameters change and noise of an instrument on the LST and LSE inversion errors. The results show that: (1) center wavelength shifts and noise affect the inversion errors strongly, while FWHM changes affect them weakly; (2) the LST and LSE inversion errors increase with the center wavelength shift ratio in a quadratic function and increase with FWHM change ratio slowly and linearly for both the inversion methods, however they increase with NEDT in an S-curve for ISSTES while they increase with NEDT slightly and linearly for ARTEMISS. During the design and development of a hyperspectral thermal infrared instrument, it is highly recommended to keep the potential center wavelength shift within 1 band and keep NEDT within 0.1K (corresponding LST error < 1K and LSE error < 0.015) for normal applications and within 0.03K (corresponding LST error < 0.5K and LSE error < 0.01) for better application effect and level.

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Vicarious Calibration of FengYun-3D MERSI-II at Railroad Valley Playa Site: A Case for Sensors with Large View Angles

Remote Sensing ◽

10.3390/rs13071347 ◽

2021 ◽

Vol 13 (7) ◽

pp. 1347

Author(s):

Yepei Chen ◽

Kaimin Sun ◽

Wenzhuo Li ◽

Xiuqing Hu ◽

Pengfei Li ◽

...

Keyword(s):

Field Measurements ◽

Calibration Method ◽

Radiative Transfer Model ◽

Transfer Model ◽

Radiometric Calibration ◽

Vicarious Calibration ◽

In Situ Data ◽

Benchmark Datasets ◽

Moderate Resolution Imaging Spectroradiometer

Vicarious calibration, as one on-orbit calibration method, is a supplement to onboard calibration of sensors. The application of vicarious calibration, however, is greatly limited due to the time- and effort-consuming field measurements of atmosphere and surface. Fortunately, the Radiometric Calibration Network (RadCalNet) provides automated in situ data at multiple sites, thus increasing the opportunities to achieve ongoing ground-reference calibration of in-orbit instruments. The MEdium Resolution Spectrum Imager-II (MERSI-II) onboard FengYun-3D (FY) has the temporal, spectral, spatial, and radiometric capacity for image capture at a level on par with other sensors used worldwide, such as the Moderate Resolution Imaging Spectroradiometer (MODIS). Its on-orbit radiometric performance, however, is assessed in a limited manner. In this study, the reflectance-based vicarious calibration method was employed to calibrate the MERSI-II sensor using ground measurements from RadCalNet at the Railroad Valley Playa site. The calibration of the MERSI-II sensor with large view angles presents difficulties due to the uncertainties introduced by surface bidirectional reflectance distribution function (BRDF) effects. Thus, we performed BRDF correction to harmonize the sensor and ground measurements to consistent observation geometries, before the in-situ measurements were taken as inputs for the 6SV radiative transfer model to predict at-sensor radiance. The calibration results were comprehensively validated with ground data and MODIS benchmark datasets. The results show that accounting for BRDF correction could improve the accuracy of vicarious calibration and ensure inter-consistency between different sensors. An analysis of the vicarious calibration of FY-3D MERSI-II yielded uncertainties of <5% for solar reflective bands, which meets the radiometric accuracy requirements typical for land-monitoring space missions. The proposed approach is also applicable to the calibration of other large footprint sensors.

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