Monitoring aerosol properties in the Indian Ocean

05 Mar 2021

Marion Dufresne
The CIMEL CE318T ship-photometer on-board the Marion Dufresne vessel (Copyright CNRS 2021)

A ship-borne photometer of CIMEL CE318-T type was permanently installed in early January 2021 aboard the French research vessel Marion Dufresne in the frame of the MAP-IO (Marion Dufresne Atmospheric Program - Indian Ocean) research programme [1].

The ship-borne instrument was developed at Laboratoire d'Optique Atmosphérique (LOA), Lille (France) to enable measurement of atmospheric aerosols from mobile platforms, and to expand and automate the AErosol RObotic NETwork (AERONET) coverage to the vast ocean [2], an area which is currently manually operated within the Maritime Aerosol Network (MAN) branch of AERONET [3].

The instrument will be engaged mainly in the Southern Hemisphere/Indian Ocean to measure Aerosol Optical Depth (AOD) and column-mean Ångström coefficient. The campaign that just started is the result of the following preparatory activities, where the system was tested, improved and validated [4]:

  1. Mediterranean and Arabian basins (AQABA - 2017) [5]
  2. During trans-Atlantic cruises aboard the German vessel Polarstern (OCEANET - 2018, 2019) [6]
  3. Indian Ocean (SEA2CLOUD - 2020)

Preliminary results from MAP-IO

Data are transmitted via satellite to LOA/CNRS where they are processed to produce spectral AOD, water vapour content, Ångström exponent, and sky radiance for AERONET. The joint retrieval of spectral AOD and sky radiances is funded in the frame of several national and European programs such as ESA/IDEAS-QA4EO, AERONET, ACTRIS, Labex CaPPA.

Map of AOD
Map of the first daytime recorded AOD (level 1.5) between 13 and 31 January 2021 (Source: Luc Blarel at LOA/CNRS/U. Lille).

Next steps and perspectives

The automatic AERONET compatible ship-borne CE318-T photometer will contribute to satellite Cal/Val activities of current and upcoming Earth observation missions. Several research or commercial vessels will be equipped with this system to continuously measure and monitor aerosol properties over the oceans. A processing chain dedicated to mobile platforms is under development and will be implemented at the ACTRIS Data Center.

The system will again be improved during the MAP-IO operation in the frame of AGORA-Lab, a joint partnership programme between CNRS-LOA and CIMEL SME. A future version could target radiance measurements from the ocean surface as well, possibly measuring water-leaving radiance. Integration of an automatic lidar system, ideal companion of photometer and in situ aerosol measurements, will be also tested.


For further information on this project, please contact:


  1. Tulet P. et al., Marion Dufresne Atmospheric Program, Indian Ocean (MAP-IO), Surveillance, bancarisation et exploitation scientifique des données atmosphériques sur l’océan Indien dans un contexte changement climatique, LACY, Université de la Réunion, 2019.
  2. Goloub, P., Blarel, L., Dubois, G., Popovici, I., Podvin, T., Torres, B., Victori, S., Maupin, F., and Pikridas, M.: Current results on mobile system prototype development for Aerosol Cal/Val activities, ESA/IDEAS Project WP 3440-1/3/5, 12 December 2017.
  3. Smirnov, A., B. N. Holben, I. Slutsker, D. M. Giles, C. R. McClain, T. F. Eck, S. M. Sakerin, A. Macke, P. Croot, G. Zibordi, P. K. Quinn, J. Sciare, S. Kinne, M. Harvey, T. J. Smyth, S. Piketh, T. Zielinski, A. Proshutinsky, J. I. Goes, N. B. Nelson, P. Larouche, V. F. Radionov, P. Goloub, K. Krishna Moorthy, R. Matarrese, E. J. Robertson, and F. Jourdin (2009), Maritime Aerosol Network as a component of Aerosol Robotic Network, J. Geophys. Res., 114, D06204, doi:10.1029/2008JD01125
  4. Popovici, I., Goloub, P., Blarel, L., Podvin, T., Dubois, G., Torres, B., Victori, S., Maupin, S., Ducos, F., Loisil, R., Delegove, R., Unga, F., Pikridas, M., Sciare, J., Yin, Z., Baars, H. Mobile systems for aerosol remote sensing: Development, Evaluation and Data Processing by LOA using ACTRIS/non ACTRIS data, ACTRIS-2 workshop, Darmstadt/EUMETSAT, 2019.
  5. Unga F., Popovici, I-E, Dubois, G., Blarel L., Pikridas M., Vouterakos P., Sciare J., Goloub P., Torres B., Victori S., Maupin F, Canini M., Mortier A., Lelieveld J., Mobile ship-borne sun/sky/lunar photometer and ceilometer observations during the AQABA campaign, Geophysical Research Abstracts, 2019, Vol. 21.
  6. Yin, Z., Ansmann, A., Baars, H., Seifert, P., Engelmann, R., Radenz, M., Jimenez, C., Herzog, A., Ohneiser, K., Hanbuch, K., Blarel, L., Goloub, P., Dubois, G., Victori, S., and Maupin, F.: Aerosol measurements with a shipborne Sun–sky–lunar photometer and collocated multiwavelength Raman polarization lidar over the Atlantic Ocean, Atmos. Meas. Tech., 12, 5685–5698,, 2019