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Welcome to the Deep Blue aerosol project webpage

Deep Blue uses measurements made by satellite instruments orbiting the Earth to determine the amount of aerosols in the atmosphere, and the properties of those aerosols. 'Aerosols' is a catch-all term covering particles suspended in the atmosphere, including but not limited to desert dust, smoke, volcanic ash, industrial smog, and sea spray. Improving our understanding of aerosols is important for reasons related to Earth's climate, human health, and ecology, as well as many others.

This website is designed to act as a single portal to provide information to both new and experienced data users about our data sets, as well as give an overview of what we do and why we do it to non-specialists. Please use the links across the top of the page to navigate, and feel free to contact us with any questions.

Recent news relating to Deep Blue, such as new data versions or publications, are listed below. You can also subscribe to our RSS feed for updates.

Validation of the ASHE algorithm, from Lee et al (2016)

New papers in Aerosol and Air Quality Research special issue

This figure from Lee et al. (2016) shows (top) time series of ASHE and MPLNET aerosol top height (ATH), (middle) VIIRS and AERONET AOD, and (bottom) ASHE and AERONET SSA from the complete algorithm (left) and simplified algorithm (right). Only best QA data are shown. The MPLNET and AERONET data are presented only if there are ASHE retrieved ATH data, while the gray dots represent the full MPLNET/AERONET data records. The black vertical line separates 2013 and 2014.

 

MODIS Terra true color overlaid with Deep Blue aerosol optical depth, showing data from May 31 2016.

MODIS Deep Blue Collection 6 data now available in NASA Worldview

MODIS Terra true color overlaid with Deep Blue aerosol optical depth, showing data from May 31 2016.

We are pleased to announce that select MODIS Collection 6 Atmospheres data products, including Deep Blue aerosol data, are now available on the NASA Worldview satellite imagery browsing tool. At present, data from 2007-2015 are currently available. Earlier years, as well as 2016 data (and near-real-time availability), are being added.

Key features of Worldview include:

Aerosols - above - clouds article featured as an EOS research spotlight

The American Geophysical Union (AGU) have selected our recent article about monitoring aerosols above clouds for a Research Spotlight. The Spotlight has been published in EOS and you can read it here.

(a) MODIS Terra scene over southeastern Asia showing smoke aerosols above clouds and (b) spectral TOA reflectance for 0.1° boxes centered around a smoke-laden cloud (red crosses) and a comparatively smoke-free cloud (blue diamonds). Vertical bars in Figure 1b indicate the standard deviation of reflectance across these boxes.

New paper published about monitoring absorbing aerosols above clouds

This Figure shows (a) MODIS Terra scene over southeastern Asia showing smoke aerosols above clouds and (b) spectral TOA reflectance for 0.1° boxes centered around a smoke-laden cloud (red crosses) and a comparatively smoke-free cloud (blue diamonds). Vertical bars in Figure 1b indicate the standard deviation of reflectance across these boxes.

 

MODIS AOD map created by Giovanni

MODIS Collection 6 aerosol products now on Giovanni visualization tool

We are pleased to report that the latest update to NASA’s Giovanni visualization portal now includes MODIS Collection 6 aerosol products, including Deep Blue. Giovanni provides a quick and easy way to look at our Level 3 data sets, as well as many other geophysical data sets, without having to download the files yourself.

 

Paper about MODIS Terra Deep Blue Collection 6 validation and stability

This figure shows the global over land area-weighted time series of DB (a) AOD at 550 nm and (b) AOD anomaly and decadal trends, from MODIS Terra (red) and Aqua (blue), and (c) the time series and decadal trend in the Terra-Aqua AOD difference. Uncertainties in calculated trends are presented as 90% confidence intervals.

 

Figure 10 from paper, showing mitigation of bow-tie distortion

Paper about the MODIS bow-tie distortion and effect on aerosol retrievals

Illustration of the effects of aggregation technique on spatial distribution of retrieved DB AOD at 550 nm near the edge of a MODIS swath. Panel (a) shows a true-color image; panel (b) shows the AOD using the standard level 2 aggregation technique, while (c) and (d) show the result of techniques designed to increasingly mitigate the effects of the bow-tie distortion on the data. Panel (d) clearly shows the greatest similarity in structure between the AOD features/cloud gaps with the true-color image. Pixels without retrievals are shaded in gray.

Case study of the ASHE algorithm over North America

Paper about aerosol height and single scattering albedo retrieval

Application of the aerosol single-scattering albedo and height estimation (ASHE) algorithm to a smoke event observed over North America on 16 July 2014. (a) VIIRS RGB image with MODIS/Aqua fire mask in red dots, (b) VIIRS Deep Blue AOD, (c) OMPS UVAI, (d) retrieved SSA and (e) ATH from ASHE, and (f) CALIOP total attenuated backscatter profile with CALIOP-derived (black circle) and ASHE-retrieved aerosol heights (cyan circle).

Example of the merging process for a MODIS Aqua granule over the Sahel.

Paper about MODIS Collection 6 Deep Blue, Dark Target, and 'merged' data sets

Example of the merging process for a MODIS Aqua granule over the Sahel. (a) A true-color image and (b) the algorithms selected for each individual retrieval . (c–e) Deep Blue (DB), Dark Target (DT) land/ocean, and merged AOD, respectively. Regions in grey lack valid AOD retrievals.