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Full article title CÆLIS: Software for assimilation, management, and processing data of an atmospheric measurement network
Journal Geoscientific Instrumentation, Methods and Data Systems
Author(s) Fuertes, David; Toledano, Carlos; González, Ramiro; Berjón, Alberto; Torres, Benjamin; Cachorro, Victoria E.; de Frutos, Ángel M.
Author affiliation(s) University of Valladolid, GRASP SAS
Primary contact Email: david at goa dot uva dot es
Year published 2018
Volume and issue 7(1)
Page(s) 67–81
DOI 10.5194/gi-7-67-2018
ISSN 21930864
Distribution license Creative Commons Attribution 4.0 International
Website https://www.geosci-instrum-method-data-syst.net/7/67/2018/
Download https://www.geosci-instrum-method-data-syst.net/7/67/2018/gi-7-67-2018.pdf (PDF)

Abstract

Given the importance of atmospheric aerosols, the number of instruments and measurement networks which focus on its characterization is growing. Many challenges are derived from standardization of protocols, monitoring of instrument status to evaluate network data quality, and manipulation and distribution of large volumes of data (raw and processed). CÆLIS is a software system which aims to simplify the management of a network, providing the scientific community a new tool for monitoring instruments, processing data in real time, and working with the data. Since 2008, CÆLIS has been successfully applied to the photometer calibration facility managed by the University of Valladolid, Spain, under the framework of the Aerosol Robotic Network (AERONET). Thanks to the use of advanced tools, this facility has been able to analyze a growing number of stations and data in real time, which greatly benefits network management and data quality control. The work describes the system architecture of CÆLIS and gives some examples of applications and data processing.

Introduction

Atmospheric aerosols are defined as solid or liquid particles suspended in the atmosphere. Many studies have shown the importance of aerosols, which play an important role in global energy balance and human activities. Among their direct impacts, aerosol particles produce radiative forcing in the atmosphere, provide nutrients for oceans, and affect human health. Aerosols generally produce a cooling effect, although an aerosol can also locally warm up the atmosphere depending on its type, height above the surface, and timescale under consideration. Indirectly, they change the chemical composition of clouds and therefore their radiative properties, lifetime, and precipitation. Improving knowledge about the distribution and composition of aerosols is one of the emerging challenges highlighted by the last IPCC report[1], where it is shown that they have the largest uncertainty for the estimates and interpretations of the Earth’s changing energy budget.

Ground-based and orbital instruments have been applied to monitor aerosol properties. Combining instruments is also possible to maximally exploit synergies. For example, satellites have demonstrated the potential of high spatial coverage and resolution, and standardized ground-based networks have the benefit of high accuracy. A common exercise is to validate satellite data with ground-based networks.

One of these ground-based networks is the Aerosol Robotic Network (AERONET).[2] Led by NASA (National Aeronautics and Space Administration; http://aerosnet.gsfc.nasa.gov) and PHOTONS (PHOtométrie pour le Traitement Opérationnel de Normalisation Satellitaire; http://loaphotons.univ-lille1.fr/), AERONET is built as a federation of sub-networks with highly standardized procedures: instrument, calibration, processing, and data distribution. It was created in the 1990s with the objective of global monitoring of aerosol optical properties from the ground, as well as validating satellite retrievals of aerosols. The standard instrument used by the network is the photometer Cimel318. It is an automatic filter radiometer with a two-axis robot and nine spectral channels covering the spectral range of 340 to 1640 nm. It collects direct solar and lunar measurements, sky radiances in the almucantar and principal planes, and hybrid geometrical configurations. Once the data are validated through instrument status and cloud screening, aerosol optical depth (AOD) can be obtained as a direct product of the nine wavelengths. Using inversion algorithms[3][4], many other parameters can be retrieved, such as size distribution, complex refractive index, portion of spherical particles, and single-scattering albedo.

References

  1. Intergovernmental Panel on Climate Change (2014). Climate Change 2013 – The Physical Science Basis: Working Group I Contribution to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge University Press. doi:10.1017/CBO9781107415324. ISBN 9781107415324. 
  2. Holben, B.N.; Eck, T.F.; Slutsker, I. et al. (1998). "AERONET—A Federated Instrument Network and Data Archive for Aerosol Characterization". Remote Sensing of Environment 66 (1): 1–16. doi:10.1016/S0034-4257(98)00031-5. 
  3. Dubovik, O.; King, M.D. (2000). "A flexible inversion algorithm for retrieval of aerosol optical properties from Sun and sky radiance measurements". Journal of Geophysical Research: Atmospheres 105 (D16): 20673-20696. doi:10.1029/2000JD900282. 
  4. Dubovik, O.; Sinyuk, A.; Lapyonok, T. et al. (2006). "Application of spheroid models to account for aerosol particle nonsphericity in remote sensing of desert dust". Journal of Geophysical Research: Atmospheres 111 (D11). doi:10.1029/2005JD006619. 

Notes

This presentation is faithful to the original, with only a few minor changes to presentation. Grammar was cleaned up for smoother reading. In some cases important information was missing from the references, and that information was added. The original article lists references alphabetically, but this version—by design—lists them in order of appearance.