Impact of Aerosol Type on Atmospheric Correction of Case II Waters

Abstract. This paper describes the latest version of algorithm MAIAC used for processing of the MODIS Collection 6 data record. Since initial publication in 2011–2012, MAIAC has changed considerably to adapt global processing and improve cloud/snow detection, aerosol retrievals and atmospheric correction of MODIS data. The main changes include 1) transition from 25 km to 1 km scale for retrieval of the spectral regression coefficient (SRC) which helped remove occasional blockiness at 25 km scale in the aerosol optical depth (AOD) and in the surface reflectance; 2) continuous improvements of cloud detection; 3) introduction of “Smoke” and “Dust” tests to discriminate absorbing fine and coarse mode aerosols; 4) adding over-water processing; 5) general optimization of the LUT-based radiative transfer for the global processing, and others. MAIAC provides an inter-disciplinary suite of atmospheric and land products, including: cloud mask (CM), column water vapor (CWV), AOD at 0.47 and 0.55 μm, aerosol type (background/smoke/dust), and fine mode fraction over water; spectral bidirectional reflectance factors (BRF), parameters of Ross-Thick Li-Sparse (RTLS) BRDF model and instantaneous albedo; for snow-covered surfaces, we provide sub-pixel snow fraction and snow grain size. All products come in standard HDF4 format at 1 km resolution, except BRF which is also provided at 500 m resolution, on Sinusoidal grid adopted by the MODIS land team. All products are provided on per-observation basis in daily files except BRDF/albedo which is reported every 8 days. Because MAIAC uses a time series approach, the BRDF/albedo are naturally gap-filled over land where missing values are filled-in with results from the previous retrieval. While the BRDF model is reported for MODIS land bands 1–7 and ocean band 8, BRF is reported for both land and ocean bands 1–12. This paper focuses on MAIAC cloud detection, aerosol retrievals and atmospheric correction and describes MCD19 data products and quality assurance (QA) flags.

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Atmospheric correction of ENVISAT/MERIS data over case II waters: the use of black pixel assumption in oxygen and water vapour absorption bands

International Journal of Remote Sensing ◽

10.1080/01431161.2011.632656 ◽

2011 ◽

Vol 33 (12) ◽

pp. 3713-3732 ◽

Cited By ~ 1

Author(s):

Jingjing Zhu ◽

Jin Chen ◽

Bunkei Matsushita ◽

Wei Yang ◽

Takehiko Fukushima

Keyword(s):

Water Vapour ◽

Atmospheric Correction ◽

Absorption Bands ◽

Case Ii Waters ◽

Black Pixel ◽

Water Vapour Absorption

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The atmospheric correction of water colour and the quantitative retrieval of suspended particulate matter in Case II waters: Application to MERIS

International Journal of Remote Sensing ◽

10.1080/014311699212434 ◽

1999 ◽

Vol 20 (9) ◽

pp. 1713-1733 ◽

Cited By ~ 151

Author(s):

G. F. Moore ◽

J. Aiken ◽

S. J. Lavender

Keyword(s):

Particulate Matter ◽

Suspended Particulate Matter ◽

Atmospheric Correction ◽

Water Colour ◽

Case Ii Waters ◽

Suspended Particulate

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EVALUATION OF THE AEROSOL TYPE EFFECT ON THE SURFACE REFLECTANCE RETRIEVAL USING CHRIS/PROBA IMAGES OVER LAND

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

10.5194/isprsarchives-xl-7-w3-1311-2015 ◽

2015 ◽

Vol XL-7/W3 ◽

pp. 1311-1316 ◽

Cited By ~ 1

Author(s):

C. Tirelli ◽

C. Manzo ◽

G. Curci ◽

C. Bassani

Keyword(s):

Land Surface ◽

Transport Model ◽

Atmospheric Correction ◽

Hyperspectral Data ◽

Radiative Transfer Model ◽

Urban Site ◽

Transfer Model ◽

Surface Reflectance ◽

Aerosol Model ◽

Aerosol Type

Surface reflectance has a central role in the analysis of land surface for a broad variety of agricultural, geological and urban studies. An accurate atmospheric correction, obtained by an appropriate selection of aerosol type and loading, is the first requirement for a reliable surface reflectance estimation. The aerosol type is defined by its micro-physical properties, while the aerosol loading is described by optical thickness at 550 nm. The aim of this work is to evaluate the radiative impact of the aerosol model on the surface reflectance obtained from CHRIS (Compact High Resolution Imaging Spectrometer) hyperspectral data over land by using the specifically developed algorithm CHRIS@CRI (CHRIS Atmospherically Corrected Reflectance Imagery) based on the 6SV radiative transfer model. Five different aerosol models have been used: one provided by the AERONET inversion products (used as reference), three standard aerosol models in 6SV, and one obtained from the output of the GEOS-Chem global chemistry-transport model (CTM). As test case the urban site of Bruxelles and the suburban area of Rome Tor Vergata have been considered. The results obtained encourages the use of CTM in operational retrieval and provides an evaluation of the role of the aerosol model in the atmospheric correction process, considering the different microphysical properties impact.

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The Sensitivity of SeaWiFS Ocean Color Retrievals to Aerosol Amount and Type

Journal of Atmospheric and Oceanic Technology ◽

10.1175/jtech-d-15-0121.1 ◽

2016 ◽

Vol 33 (6) ◽

pp. 1185-1209 ◽

Cited By ~ 15

Author(s):

Ralph A. Kahn ◽

Andrew M. Sayer ◽

Ziauddin Ahmad ◽

Bryan A. Franz

Keyword(s):

Ocean Color ◽

Atmospheric Correction ◽

Single Scattering ◽

Medium Size ◽

Wide Field ◽

Anthropogenic Aerosols ◽

Transport Pathways ◽

Nonabsorbing Medium ◽

Absorbing Aerosols ◽

Aerosol Type

AbstractAs atmospheric reflectance dominates top-of-the-atmosphere radiance over ocean, atmospheric correction is a critical component of ocean color retrievals. This paper explores the operational Sea-viewing Wide Field-of-view Sensor (SeaWiFS) algorithm atmospheric correction with ~13 000 coincident surface-based aerosol measurements. Aerosol optical depth at 440 nm (AOD440) is overestimated for AOD below ~0.1–0.15 and is increasingly underestimated at higher AOD; also, single-scattering albedo (SSA) appears overestimated when the actual value <~0.96. AOD440 and its spectral slope tend to be overestimated preferentially for coarse-mode particles. Sensitivity analysis shows that changes in these factors lead to systematic differences in derived ocean water-leaving reflectance (Rrs) at 440 nm. The standard SeaWiFS algorithm compensates for AOD anomalies in the presence of nonabsorbing, medium-size-dominated aerosols. However, at low AOD and with absorbing aerosols, in situ observations and previous case studies demonstrate that retrieved Rrs is sensitive to spectral AOD and possibly also SSA anomalies. Stratifying the dataset by aerosol-type proxies shows the dependence of the AOD anomaly and resulting Rrs patterns on aerosol type, though the correlation with the SSA anomaly is too subtle to be quantified with these data. Retrieved chlorophyll-a concentrations (Chl) are affected in a complex way by Rrs differences, and these effects occur preferentially at high and low Chl values. Absorbing aerosol effects are likely to be most important over biologically productive waters near coasts and along major aerosol transport pathways. These results suggest that future ocean color spacecraft missions aiming to cover the range of naturally occurring and anthropogenic aerosols, especially at wavelengths shorter than 440 nm, will require better aerosol amount and type constraints.

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