MODIS reflective solar bands calibration improvements in Collection 6

Sun, Junqiang; Angal, Amit; Xiong, Xiaoxiong; Chen, Hongda; Geng, Xu; Wu, Aisheng; Choi, Taeyoung; Chu, Mike

doi:10.1117/12.979733

Cited by 48 publications

(44 citation statements)

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“…The C5 and C6 ice cloud models described above are used to compute the Look-up Tables (LUTs) in the operational MODIS retrieval implementation. The Level 1B reflectance data used in C5 and C6 cloud optical property re-trievals are slightly different due to updated reflective solar bands calibration implemented in the C6 product [29]. In the granule used in the study, band 2 and 7 reflectance differences between C5 and C6 data are less than 0.001, so the retrieved C5 and C6 ice cloud optical properties can be assumed to correspond to the same radiation field.…”

Section: Validation Using Remote Sensing Datamentioning

confidence: 99%

Validation of quasi-invariant ice cloud radiative quantities with MODIS satellite-based cloud property retrievals

Ding

Yang

Kattawar

et al. 2017

Journal of Quantitative Spectroscopy and Radiative Transfer

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Similarity relations applied to ice cloud radiance calculations are theoretically analyzed and numerically validated. If t(1-v) and t(1-vg) are conserved where t is optical thickness, v the single-scattering albedo, and g the asymmetry factor, it is possible that substantially different phase functions may give rise to similar radiances in both conservative and non-conservative scattering cases, particularly in the case of large optical thicknesses. In addition to theoretical analysis, this study uses operational ice cloud optical 1/2 , also tend to be similar.

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Section: Validation Using Remote Sensing Datamentioning

confidence: 99%

Validation of quasi-invariant ice cloud radiative quantities with MODIS satellite-based cloud property retrievals

Ding

Yang

Kattawar

et al. 2017

Journal of Quantitative Spectroscopy and Radiative Transfer

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“…This closely follows the MODIS Collection 6 approach and yields similar retrieval uncertainties for both the ASTER and MODIS results. However, while for ASTER the calibration and model uncertainties are assumed to be a constant value of 5 %, uncertainties in the operational MODIS C6 cloud products include spectral, scene-dependent Level 1B uncertainty indices (Sun et al, 2012).…”

Section: Uncertainty Contributionsmentioning

confidence: 99%

Marine boundary layer cloud property retrievals from high-resolution ASTER observations: case studies and comparison with Terra MODIS

et al. 2016

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Abstract.A research-level retrieval algorithm for cloud optical and microphysical properties is developed for the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) aboard the Terra satellite. It is based on the operational MODIS algorithm. This paper documents the technical details of this algorithm and evaluates the retrievals for selected marine boundary layer cloud scenes through comparisons with the operational MODIS Data Collection 6 (C6) cloud product. The newly developed, ASTERspecific cloud masking algorithm is evaluated through comparison with an independent algorithm reported in Zhao and Di Girolamo (2006). To validate and evaluate the cloud optical thickness (τ ) and cloud effective radius (r eff ) from ASTER, the high-spatial-resolution ASTER observations are first aggregated to the same 1000 m resolution as MODIS. Subsequently, τ aA and r eff, aA retrieved from the aggregated ASTER radiances are compared with the collocated MODIS retrievals. For overcast pixels, the two data sets agree very well with Pearson's product-moment correlation coefficients of R > 0.970. However, for partially cloudy pixels there are significant differences between r eff, aA and the MODIS results which can exceed 10 µm. Moreover, it is shown that the numerous delicate cloud structures in the example marine boundary layer scenes, resolved by the high-resolution ASTER retrievals, are smoothed by the MODIS observations. The overall good agreement between the research-level ASTER results and the operational MODIS C6 products proves the feasibility of MODIS-like retrievals from ASTER reflectance measurements and provides the basis for future studies concerning the scale dependency of satellite observations and three-dimensional radiative effects.

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“…MODIS has no onboard capability to track changes in its polarization sensitivity (Sun and Xiong, 2007). It was optimized during the design phase and was characterized before launch.…”

Section: Polarization Correction Of Modis Terra Datamentioning

confidence: 99%

Scientific impact of MODIS C5 calibration degradation and C6+ improvements

et al. 2014

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Abstract. The Collection 6 (C6) MODIS (Moderate Resolution Imaging Spectroradiometer) land and atmosphere data sets are scheduled for release in 2014. C6 contains significant revisions of the calibration approach to account for sensor aging. This analysis documents the presence of systematic temporal trends in the visible and near-infrared (500 m) bands of the Collection 5 (C5) MODIS Terra and, to lesser extent, in MODIS Aqua geophysical data sets. Sensor degradation is largest in the blue band (B3) of the MODIS sensor on Terra and decreases with wavelength. Calibration degradation causes negative global trends in multiple MODIS C5 products including the dark target algorithm's aerosol optical depth over land and Ångström exponent over the ocean, global liquid water and ice cloud optical thickness, as well as surface reflectance and vegetation indices, including the normalized difference vegetation index (NDVI) and enhanced vegetation index (EVI). As the C5 production will be maintained for another year in parallel with C6, one objective of this paper is to raise awareness of the calibration-related trends for the broad MODIS user community. The new C6 calibration approach removes major calibrations trends in the Level 1B (L1B) data. This paper also introduces an enhanced C6+ calibration of the MODIS data set which includes an additional polarization correction (PC) to compensate for the increased polarization sensitivity of MODIS Terra since about 2007, as well as detrending and TerraAqua cross-calibration over quasi-stable desert calibration sites. The PC algorithm, developed by the MODIS ocean biology processing group (OBPG), removes residual scan angle, mirror side and seasonal biases from aerosol and surface reflectance (SR) records along with spectral distortions of SR. Using the multiangle implementation of atmospheric correction (MAIAC) algorithm over deserts, we have also developed a detrending and cross-calibration method which removes residual decadal trends on the order of several tenths of 1 % of the top-of-atmosphere (TOA) reflectance in the visible and near-infrared MODIS bands B1-B4, and provides a good consistency between the two MODIS sensors. MA-IAC analysis over the southern USA shows that the C6+ approach removed an additional negative decadal trend of Terra NDVI ∼ 0.01 as compared to Aqua data. This change is particularly important for analysis of vegetation dynamics and trends in the tropics, e.g., Amazon rainforest, where the morning orbit of Terra provides considerably more cloudfree observations compared to the afternoon Aqua measurements.

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MODIS reflective solar bands calibration improvements in Collection 6

Cited by 48 publications

References 0 publications

Validation of quasi-invariant ice cloud radiative quantities with MODIS satellite-based cloud property retrievals

Validation of quasi-invariant ice cloud radiative quantities with MODIS satellite-based cloud property retrievals

Marine boundary layer cloud property retrievals from high-resolution ASTER observations: case studies and comparison with Terra MODIS

Scientific impact of MODIS C5 calibration degradation and C6+ improvements

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