Intercomparison of MODIS albedo retrievals and in situ measurements across the global FLUXNET network

Cescatti, Alessandro; Marcolla, Barbara; Vannan, S. K. Santhana; Pan, Jerry; Román, M. O.; Yang, Xiaoyuan; Ciais, Philippe; Cook, R.B.; Law, B. E.; Matteucci, Giorgio; Migliavacca, Mirco; Moors, E.J.; Richardson, Andrew D.; Seufert, G.; Schaaf, Crystal B.

doi:10.1016/j.rse.2012.02.019

Cited by 284 publications

(216 citation statements)

References 51 publications

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“…The MODIS dataset (MCD43C3, other versions also exist) provides both black-sky and white-sky albedo. The MODIS albedo products have been shown to be stable and accurate in both radiometric and geolocation aspects (Cescatti et al, 2012;Wolfe et al, 2002), and the spatial resolution of MODIS is considerably better than AVHRR (GAC).…”

Section: Previous Long-term Surface Albedo Timeseriesmentioning

confidence: 99%

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CLARA-SAL: a global 28 yr timeseries of Earth's black-sky surface albedo

et al. 2013

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We present a novel 28 yr dataset of Earth's black-sky surface albedo, derived from AVHRR instruments. The dataset is created using algorithms to separately derive the surface albedo for different land use areas globally. Snow, sea ice, open water and vegetation are all treated independently. The product features corrections for the atmospheric effect in satellite-observed surface radiances, a BRDF correction for the anisotropic reflectance properties of natural surfaces, and a novel topography correction of geolocation and radiometric accuracy of surface reflectance observations over mountainous areas. The dataset is based on a homogenized AVHRR radiance timeseries. The product is validated against quality-controlled in situ observations of clear-sky surface albedo at various BSRN sites around the world. Snow and ice albedo retrieval validation is given particular attention using BSRN sites over Antarctica, Greenland Climate Network stations on the Greenland Ice Sheet (GrIS), as well as sea ice albedo data from the SHEBA and Tara expeditions. The product quality is found to be comparable to other previous long-term surface albedo datasets from AVHRR

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Section: Previous Long-term Surface Albedo Timeseriesmentioning

confidence: 99%

“…The MODIS albedo product and its validation efforts have been extensively described in the literature (e.g. Schaaf et al, 2002;Jin et al, 2003;Cescatti et al, 2012). To match the CLARA-SAL products to the MODIS 16-day albedo means, the following procedures were followed.…”

Section: Comparison Of the Dataset With Mcd43c3 Productsmentioning

confidence: 99%

CLARA-SAL: a global 28 yr timeseries of Earth's black-sky surface albedo

et al. 2013

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“…The agreement is generally quite good for BSRN sites, with metrics that are comparable to MODIS-only albedo estimates [31,56] and generally better than AVHRR-only estimates [14,32]. The observed biases (MBD and MABD) are less than 0.05 at all BSRN sites, with no systematic tendencies for either over-or underestimation.…”

Section: Results From Demonstrator Dataset Evaluation Against Bsrn Anmentioning

confidence: 64%

“…With some sites, it is in good agreement, while others displayed a clear overestimation in SCM. Some differences against the FLUXNET data are similar than those from MODIS-only evaluations in the literature [56], yet the other results point towards the need for the further development of the atmospheric correction protocol and verification of the validity of the applied atmospheric composition inputs (AOD and water vapor).…”

Section: Discussionmentioning

confidence: 68%

“…The results from MODIS validation [56] also note that the cropland FLUXNET sites display a large internal variability in measured albedo relative to that seen from satellites, possibly related to heterogeneity in farmed crop and impacts from agricultural activities. Indeed, both cropland sites show a large change in measured albedo in late August (Figure 3b), likely coinciding with harvest activities.…”

Section: Approximationmentioning

confidence: 81%

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A Multisensor Approach to Global Retrievals of Land Surface Albedo

et al. 2018

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Satellite-based retrievals offer the most cost-effective way to comprehensively map the surface albedo of the Earth, a key variable for understanding the dynamics of radiative energy interactions in the atmosphere-surface system. Surface albedo retrievals have commonly been designed separately for each different spaceborne optical imager. Here, we introduce a novel type of processing framework that combines the data from two polar-orbiting optical imager families, the Advanced Very High-Resolution Radiometer (AVHRR) and Moderate Resolution Imaging Spectroradiometer (MODIS). The goal of the paper is to demonstrate that multisensor albedo retrievals can provide a significant reduction in the sampling time required for a robust and comprehensive surface albedo retrieval, without a major degradation in retrieval accuracy, as compared to state-of-the-art single-sensor retrievals. We evaluated the multisensor retrievals against reference in situ albedo measurements and compare them with existing datasets. The results show that global land surface albedo retrievals with a sampling period of 10 days can offer near-complete spatial coverage, with a retrieval bias mostly comparable to existing single sensor datasets, except for bright surfaces (deserts and snow) where the retrieval framework shows degraded performance because of atmospheric correction design compromises. A level difference is found between the single sensor datasets and the demonstrator developed here, pointing towards a need for further work in the atmospheric correction, particularly over bright surfaces, and inter-sensor radiance homogenization. The introduced framework is expandable to include other sensors in the future.

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Direct estimation of land surface albedo from VIIRS data: Algorithm improvement and preliminary validation

Wang

Liang

et al. 2013

JGR Atmospheres

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[1] Land surface albedo (LSA), part of the Visible Infrared Imaging Radiometer Suite (VIIRS) surface albedo environmental data record (EDR), is an essential variable regulating shortwave energy exchange between the land surface and the atmosphere. Two sub-algorithms, the dark pixel sub-algorithm (DPSA) and the bright pixel sub-algorithm (BPSA), were proposed for retrieving LSA from VIIRS data. The BPSA estimates LSA directly from VIIRS top-of-atmosphere (TOA) reflectance through simulation of atmospheric radiative transfer. Several changes have been made to improve the BPSA since the deployment of VIIRS. A database of the Moderate Resolution Imaging Spectroradiometer (MODIS) bidirectional reflectance distribution function (BRDF) is collected and converted to bidirectional reflectance at VIIRS bands. The converted reflectance is then used as input to the atmospheric radiative transfer model to generate a look-up table (LUT) of regression coefficients with consideration of surface BRDF. Before its implementation in the operational system, the new BPSA is tested on the local infrastructure. The incorporation of the surface BRDF improves the accuracy of LSA estimation and reduces the temporal variation of LSA over stable surfaces. VIIRS LSA retrievals agree well with the MODIS albedo products. Comparison with field measurements at seven Surface Radiation (SURFRAD) Network sites shows that VIIRS LSA retrieved from the LUT with surface BRDF has an R 2 value of 0.80 and root mean square error of 0.049, better than MODIS albedo products. The VIIRS results have a slight negative bias of 0.004, whereas the MODIS albedo is underestimated with a larger negative bias of 0.026.

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Intercomparison of MODIS albedo retrievals and in situ measurements across the global FLUXNET network

Cited by 284 publications

References 51 publications

CLARA-SAL: a global 28 yr timeseries of Earth's black-sky surface albedo

CLARA-SAL: a global 28 yr timeseries of Earth's black-sky surface albedo

A Multisensor Approach to Global Retrievals of Land Surface Albedo

Direct estimation of land surface albedo from VIIRS data: Algorithm improvement and preliminary validation

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