Improvements of 6S Look-Up-Table Based Surface Reflectance Employing Minimum Curvature Surface Method

AbstractWe propose a methodology employing an interpolation technique on the Second Simulation of a Satellite Signal (6S) look-up table (LUT) to improve surface reflectance retrieval using Himawari-8/Advanced Himawari Imager (AHI). A minimum curvature surface (MCS) technique was used to refine the 6S LUT, and the solar zenith angle (SZA) and viewing zenith angle (VZA) increments were narrowed by 0.5°. The interpolation processing time was relatively short, about 3172 s per channel, and the interpolated xa and xb were well represented by the changes in SZA and VZA. An evaluation of the interpolated xa and xb for six cases revealed a relative mean absolute error of less than 5% for all channels and cases; however, a slight difference was evident for higher values of SZA and VZA. To evaluate the surface reflectance, we compared the surface reflectance derived using 6S LUT with that calculated using 6S only. Application of the interpolated 6S LUT showed a lower relative root mean square error (RRMSE) of 0.65% to 9.29% for all channels, than before interpolation. The improvement in surface reflectance measurements increased with the SZA. For a SZA above 75°, the RRMSE improved significantly for all channels (by 11.33–45.1%). In addition, when the MCS method was applied, the surface reflectance measurements improved without spatial discontinuity and showed good agreement with 6S results in a linear profile analyses. Thus, the method proposed can improve LUT based surface reflectance measurements in less time and increase the availability of surface reflectance data based on geostationary satellites.

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A relation between landsat digital numbers, surface reflectance, and the cosine of the solar zenith angle

Remote Sensing of Environment ◽

10.1016/0034-4257(82)90006-2 ◽

1982 ◽

Vol 12 (1) ◽

pp. 39-55 ◽

Cited By ~ 9

Author(s):

William S. Kowalik ◽

Stuart E. Marsh ◽

Ronald J.P. Lyon

Keyword(s):

Zenith Angle ◽

Solar Zenith Angle ◽

Surface Reflectance

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Evaluation of the MERIS aerosol product over land with AERONET

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-8-3721-2008 ◽

2008 ◽

Vol 8 (1) ◽

pp. 3721-3759 ◽

Cited By ~ 4

Author(s):

J. Vidot ◽

R. Santer ◽

O. Aznay

Keyword(s):

Optical Properties ◽

Surface Reflectance ◽

Aerosol Optical Properties ◽

Simple Criterion ◽

Imaging Spectrometer ◽

Inherent Optical Properties ◽

Look Up Table ◽

Medium Resolution ◽

Reflectance Model ◽

Resolution Imaging

Abstract. The Medium Resolution Imaging Spectrometer (MERIS) launched in February 2002 on-board the ENVISAT spacecraft is making global observations of top-of-atmosphere (TOA) radiances. Aerosol optical properties are retrieved over land using Look-Up Table (LUT) based algorithm and surface reflectances in the blue and the red spectral regions. We compared instantaneous aerosol optical thicknesses retrieved by MERIS in the blue and the red at locations containing sites within the Aerosol Robotic Network (AERONET). Between 2002 and 2005, a set of 500 MERIS images were used in this study. The result shows that, over land, MERIS aerosol optical thicknesses are well retrieved in the blue and poorly retrieved in the red, leading to an underestimation of the Angstrom coefficient. Correlations are improved by applying a simple criterion to avoid scenes probably contaminated by thin clouds. To investigate the weakness of the MERIS algorithm, ground-based radiometer measurements have been used in order to retrieve new aerosol models, based on their Inherent Optical Properties (IOP). These new aerosol models slightly improve the correlation, but the main problem of the MERIS aerosol product over land can be attributed to the surface reflectance model in the red.

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Determination of land surface reflectance using the AATSR dual-view capability

Atmospheric Measurement Techniques Discussions ◽

10.5194/amtd-7-7451-2014 ◽

2014 ◽

Vol 7 (7) ◽

pp. 7451-7494

Author(s):

L. Sogacheva ◽

P. Kolmonen ◽

T. H. Virtanen ◽

E. Rodriguez ◽

A.-M. Sundström ◽

...

Keyword(s):

Land Surface ◽

Atmospheric Correction ◽

Correlation Coefficients ◽

Absolute Error ◽

Surface Reflectance ◽

Imaging Spectrometer ◽

Comparison Results ◽

Moderate Resolution ◽

The Difference ◽

Along Track

Abstract. In this study, a method is presented to retrieve the surface reflectance using reflectance measured at the top of the atmosphere for the two views provided by the Along-Track Scanning Radiometer (AATSR). In the first step, the aerosol optical depth (AOD) is obtained using the AATSR dual view algorithm (ADV) by eliminating the effect of the surface on the measured radiances. Hence the AOD is independent of surface properties and can thus be used in the second step to provide the aerosol part of the atmospheric correction which is needed for the surface reflectance retrieval. The method is applied to provide monthly maps of both AOD and surface reflectance at two wavelengths (555 and 659 nm) for the whole year of 2007. The results are validated vs. surface reflectance provided by the AERONET-based Surface Reflectance Validation Network (ASRVN). Correlation coefficients are 0.8 and 0.9 for 555 and 659 nm, respectively. The standard deviation is 0.001 for both wavelengths and the absolute error is less than 0.02. Pixel-by-pixel comparison with MODIS (MODerate resolution Imaging Spectrometer) monthly averaged surface reflectances show a good correlation (0.91 and 0.89 for 555 and 659 nm, respectively) with some (up to 0.05) overestimation by ADV over bright surfaces. The difference between the ADV and MODIS retrieved surface reflectance is smaller than ±0.025 for 68.3% of the collocated pixels at 555 nm and 79.9% of the collocated pixels at 659 nm. An application of the results over Australia illustrates the variation of the surface reflectances for different land cover types. The validation and comparison results suggest that the algorithm can be successfully used for the both AATSR and ATSR-2 (which has characteristics similar to AATSR) missions, which together cover 17 years period of measurements (1995–2012), as well as a prototype for The Sea and Land Surface Temperature Radiometer (SLSTR) to be launched in 2015 onboard the Sentinel-3 satellite.

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Using a Parameterization of a Radiative Transfer Model to Build High-Resolution Maps of Typical Clear-Sky UV Index in Catalonia, Spain

Journal of Applied Meteorology ◽

10.1175/jam2237.1 ◽

2005 ◽

Vol 44 (6) ◽

pp. 789-803 ◽

Cited By ~ 13

Author(s):

Jordi Badosa ◽

Josep-Abel González ◽

Josep Calbó ◽

Michiel van Weele ◽

Richard L. McKenzie

Keyword(s):

High Resolution ◽

Radiative Transfer ◽

Zenith Angle ◽

Solar Zenith Angle ◽

Absolute Error ◽

Single Scattering ◽

Radiative Transfer Model ◽

Transfer Model ◽

Uv Index ◽

Wide Range

Abstract To perform a climatic analysis of the annual UV index (UVI) variations in Catalonia, Spain (northeast of the Iberian Peninsula), a new simple parameterization scheme is presented based on a multilayer radiative transfer model. The parameterization performs fast UVI calculations for a wide range of cloudless and snow-free situations and can be applied anywhere. The following parameters are considered: solar zenith angle, total ozone column, altitude, aerosol optical depth, and single-scattering albedo. A sensitivity analysis is presented to justify this choice with special attention to aerosol information. Comparisons with the base model show good agreement, most of all for the most common cases, giving an absolute error within ±0.2 in the UVI for a wide range of cases considered. Two tests are done to show the performance of the parameterization against UVI measurements. One uses data from a high-quality spectroradiometer from Lauder, New Zealand [45.04°S, 169.684°E, 370 m above mean sea level (MSL)], where there is a low presence of aerosols. The other uses data from a Robertson–Berger-type meter from Girona, Spain (41.97°N, 2.82°E, 100 m MSL), where there is more aerosol load and where it has been possible to study the effect of aerosol information on the model versus measurement comparison. The parameterization is applied to a climatic analysis of the annual UVI variation in Catalonia, showing the contributions of solar zenith angle, ozone, and aerosols. High-resolution seasonal maps of typical UV index values in Catalonia are presented.

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A Method to Improve the Distribution of Observations in GNSS Water Vapor Tomography

Sensors ◽

10.3390/s18082526 ◽

2018 ◽

Vol 18 (8) ◽

pp. 2526 ◽

Cited By ~ 8

Author(s):

Fei Yang ◽

Jiming Guo ◽

Junbo Shi ◽

Lv Zhou ◽

Yi Xu ◽

...

Keyword(s):

Water Vapor ◽

Precipitable Water ◽

Absolute Error ◽

Satellite System ◽

Observation Data ◽

Radiosonde Station ◽

Satellite Signal ◽

Comparative Results ◽

Global Navigation Satellite ◽

Vapor Distribution

Water vapor is an important driving factor in the related weather processes in the troposphere, and its temporal-spatial distribution and change are crucial to the formation of cloud and rainfall. Global Navigation Satellite System (GNSS) water vapor tomography, which can reconstruct the water vapor distribution using GNSS observation data, plays an increasingly important role in GNSS meteorology. In this paper, a method to improve the distribution of observations in GNSS water vapor tomography is proposed to overcome the problem of the relatively concentrated distribution of observations, enable satellite signal rays to penetrate more tomographic voxels, and improve the issue of overabundance of zero elements in a tomographic matrix. Numerical results indicate that the accuracy of the water vapor tomography is improved by the proposed method when the slant water vapor calculated by GAMIT is used as a reference. Comparative results of precipitable water vapor (PWV) and water vapor density (WVD) profiles from radiosonde station data indicate that the proposed method is superior to the conventional method in terms of the mean absolute error (MAE), standard deviations (STD), and root-mean-square error (RMS). Further discussion shows that the ill-condition of tomographic equation and the richness of data in the tomographic model need to be discussed separately.

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Sensitivity analysis of 6S-based look-up table for surface reflectance retrieval

Asia-Pacific Journal of Atmospheric Sciences ◽

10.1007/s13143-015-0062-9 ◽

2015 ◽

Vol 51 (1) ◽

pp. 91-101 ◽

Cited By ~ 12

Author(s):

Chang Suk Lee ◽

Jong Min Yeom ◽

Han Lim Lee ◽

Jae-Jin Kim ◽

Kyung-Soo Han

Keyword(s):

Sensitivity Analysis ◽

Surface Reflectance ◽

Look Up Table

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The use of minimum curvature surface technique in geoid computation processing of Egypt

Arabian Journal of Geosciences ◽

10.1007/s12517-011-0418-0 ◽

2011 ◽

Vol 6 (4) ◽

pp. 1263-1272 ◽

Cited By ~ 5

Author(s):

M. Rabah ◽

M. Kaloop

Keyword(s):

Curvature Surface ◽

Geoid Computation ◽

Minimum Curvature ◽

Surface Technique

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Retrieving High-Resolution Aerosol Optical Depth from GF-4 PMS Imagery in Eastern China

Remote Sensing ◽

10.3390/rs13183752 ◽

2021 ◽

Vol 13 (18) ◽

pp. 3752

Author(s):

Zhendong Sun ◽

Jing Wei ◽

Ning Zhang ◽

Yulong He ◽

Yu Sun ◽

...

Keyword(s):

Aerosol Optical Depth ◽

Optical Depth ◽

Zenith Angle ◽

Rural Areas ◽

Urban Areas ◽

Eastern China ◽

Practical Significance ◽

Retrieval Algorithm ◽

Transfer Model ◽

Surface Reflectance

Gaofen 4 (GF-4) is a geostationary satellite, with a panchromatic and multispectral sensor (PMS) onboard, and has great potential in observing atmospheric aerosols. In this study, we developed an aerosol optical depth (AOD) retrieval algorithm for the GF-4 satellite. AOD retrieval was realized based on the pre-calculated surface reflectance database and 6S radiative transfer model. We customized the unique aerosol type according to the long time series aerosol parameters provided by the Aerosol Robotic Network (AERONET) site. The solar zenith angle, relative azimuth angle, and satellite zenith angle of the GF-4 panchromatic multispectral sensor image were calculated pixel-by-pixel. Our 1 km AOD retrievals were validated against AERONET Version 3 measurements and compared with MOD04 C6 AOD products at different resolutions. The results showed that our GF-4 AOD algorithm had a good robustness in both bright urban areas and dark rural areas. A total of 71.33% of the AOD retrievals fell within the expected errors of ±(0.05% + 20%); root-mean-square error (RMSE) and mean absolute error (MAE) were 0.922 and 0.122, respectively. The accuracy of GF-4 AOD in rural areas was slightly higher than that in urban areas. In comparison with MOD04 products, the accuracy of GF-4 AOD was much higher than that of MOD04 3 km and 10 km dark target AOD, but slightly worse than that of MOD04 10 km deep blue AOD. For different values of land surface reflectance (LSR), the accuracy of GF-4 AOD gradually deteriorated with an increase in the LSR. These results have theoretical and practical significance for aerosol research and can improve retrieval algorithms using the GF-4 satellite.

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