Articles | Volume 9, issue 4
Geosci. Model Dev., 9, 1489–1522, 2016
Geosci. Model Dev., 9, 1489–1522, 2016

Development and technical paper 21 Apr 2016

Development and technical paper | 21 Apr 2016

An 11-year global gridded aerosol optical thickness reanalysis (v1.0) for atmospheric and climate sciences

Peng Lynch1, Jeffrey S. Reid2, Douglas L. Westphal2, Jianglong Zhang3, Timothy F. Hogan2, Edward J. Hyer2, Cynthia A. Curtis2, Dean A. Hegg4, Yingxi Shi3, James R. Campbell2, Juli I. Rubin5, Walter R. Sessions1,6, F. Joseph Turk7, and Annette L. Walker2 Peng Lynch et al.
  • 1Computer Sciences Corporation Government Solutions LLC, Monterey, CA, USA
  • 2Marine Meteorology Division, Naval Research Laboratory, Monterey, CA, USA
  • 3Dept. of Atmospheric Science, University of North Dakota, Grand Forks, ND, USA
  • 4Dept. of Atmospheric Science, University of Washington, Seattle, WA, USA
  • 5National Research Council Postdoctoral Research Associate, Monterey, CA, USA
  • 6Dept. of Atmospheric and Oceanic Sciences, University of Wisconsin-Madison, WI, USA
  • 7Jet Propulsion Laboratory, Pasadena, CA, USA

Abstract. While stand alone satellite and model aerosol products see wide utilization, there is a significant need in numerous atmospheric and climate applications for a fused product on a regular grid. Aerosol data assimilation is an operational reality at numerous centers, and like meteorological reanalyses, aerosol reanalyses will see significant use in the near future. Here we present a standardized 2003–2013 global 1 × 1° and 6-hourly modal aerosol optical thickness (AOT) reanalysis product. This data set can be applied to basic and applied Earth system science studies of significant aerosol events, aerosol impacts on numerical weather prediction, and electro-optical propagation and sensor performance, among other uses. This paper describes the science of how to develop and score an aerosol reanalysis product. This reanalysis utilizes a modified Navy Aerosol Analysis and Prediction System (NAAPS) at its core and assimilates quality controlled retrievals of AOT from the Moderate Resolution Imaging Spectroradiometer (MODIS) on Terra and Aqua and the Multi-angle Imaging SpectroRadiometer (MISR) on Terra. The aerosol source functions, including dust and smoke, were regionally tuned to obtain the best match between the model fine- and coarse-mode AOTs and the Aerosol Robotic Network (AERONET) AOTs. Other model processes, including deposition, were tuned to minimize the AOT difference between the model and satellite AOT. Aerosol wet deposition in the tropics is driven with satellite-retrieved precipitation, rather than the model field. The final reanalyzed fine- and coarse-mode AOT at 550 nm is shown to have good agreement with AERONET observations, with global mean root mean square error around 0.1 for both fine- and coarse-mode AOTs. This paper includes a discussion of issues particular to aerosol reanalyses that make them distinct from standard meteorological reanalyses, considerations for extending such a reanalysis outside of the NASA A-Train era, and examples of how the aerosol reanalysis can be applied or fused with other model or remote sensing products. Finally, the reanalysis is evaluated in comparison with other available studies of aerosol trends, and the implications of this comparison are discussed.

Short summary
An 11-year, 1-degree aerosol reanalysis is presented for use in studies of aerosol effects on climate and atmospheric processes. The reanalysis uses the Navy Aerosol Analysis and Prediction System, constrained by aerosol optical thickness (AOT) data from NASA sensors. Fine and coarse mode AOT at 550 nm agrees well with ground-based measurements, and reproduces the decadal AOT trends found using standalone satellite products. This dataset is a resource for basic and applied science research.