This data set is only available for a restricted user group, please contact us if you want to access these data.
RESTRICTED only accessable in CEN/MPI net or via CliSAP login What does that mean?
MODIS stands for MODerate resolution Imaging Spectroradiometer. This sensor, equipped with over 30 spectral channels from the visible into the infrared frequency range operates from aboard the EOS-TERRA and EOS-AQUA satellites since 2000 and 2002, respectively. Thanks to its high spectral resolution and the large number of different channels a large number of different atmospheric parameters can be retrieved. Here we refer to the aerosol parameter data sets.
The MODIS aerosol products are based on calibrated, geo-located reflectances of channels at wavelengths of 0.412, 0.47, 0.55, 0.65, 0.86, 1.24, 1.63, and 2.11 µm. Depending on the surface, i.e. bright or dark, ocean or land, different channels or channel combinations are used. In addition to the reflectances, information about the atmospheric temperature and moisture profiles (product MOD07/MYD07, see also MODIS Water Vapor & PWC and MODIS Temperature Profiles), the cloud cover, and snow & ice coverage is included; over the ocean sea ice information is included. Over land in addition - depending on the parameter to be retrieved and the channels used - also information about land cover type and vegetation cover, e.g. NDVI, is included. With the aid of models for aerosol type, composition and size distribution look-up-tables (LUT) of reflectances are generated. Via a maximum likelihood or best least-square fit (or similar) method aerosol optical depth (AOD), single scattering albedo, and the number of cloud condensation nuclei that correspond to the best match between measured and LUT reflectances are retrieved.
We list the aerosol parameters which we offer via ICDC in the parameter list.
This is part of the level-3 MOD08/MYD08 data set derived from MOD04/MYD04 level-2 products of the MODIS Collection 6.1, downloaded August 2018.
Last update of data set at ICDC: April 18, 2019
Period and temporal resolution:
Coverage and spatial resolution:
The offered aerosol optical depth and other aerosol property data contain as a measure of uncertainty on the one hand the standard deviation of all level-2 grid cells used for the computation of the level-3 product.
On the other hand, for some of the products so-called "quality assessed" level-3 data sets are offered. These are the result of a weighted averaging of the level-2 data where the confidence flags of the level-2 products are used as weights (as described in the level-3 data ATBD).
The distribution of these confidence intervals (from the level-2 data) is illustrated in the level-3 data via quality flag maps which contain the global distribution of the numbers of questionable, good, very good, and total useful level-2 pixels per level-3 grid cell. These maps or histograms are not included in the standard data files but stored in separate files which contain a "__histograms" in their name.
This data set is from Collection 6.1, t he most recent one of the MODIS Collection 6 product family. Hence a substantial number inconsistencies and potential retrieval problems, which have been identified in the past (product version 4, 5), has been taken care of in MODIS Collection 6. In particular the 2nd generation of the deep blue retrieval is used and there is one data set where deep blue and dark target approaches were combined. This newest MODIS product release, 6.1. improves over the 6.0 version by mitigating the influence of electronic cross-talk between the atmospheric bands.
We refer to the documents listed in the References.
Please cite the data as follows:
Platnick, S., et al., 2017. MODIS Atmosphere L3 Daily Product. NASA MODIS Adaptive Processing System, Goddard Space Flight Center, USA: http://dx.doi.org/10.5067/MODIS/MOD08_D3.061, last access date: 5/3/2019
(if MODIS EOS-AQUA data are used accordingly: dx.doi.org/10.5067/MODIS/MYD08_D3.061)
and acknowledge the source of your data download as:
Original MODIS collection 6.1 Aerosol parameter data provided in hdf format by https://ladsweb.modaps.eosdis.nasa.gov/ were downloaded in netCDF file format from the Integrated Climate Data Centre (ICDC), CliSAP/KlimaCampus, University of Hamburg, Hamburg, Germany, icdc.cen.uni-hamburg.de