The hyperspectral and polarization resolving imager specMACS during EUREC4A

The EUREC⁴A field campaign, which takes place in January and February 2020 in the trade wind region east of Barbados, aims to Elucidate the Couplings Between Clouds, Convection and Circulation (Bony et al. 2017). For this field campaign, the hyperspectral imaging system specMACS (Ewald et al. 2016) has been equipped with additional color and polarization resolving cameras. The system is operated in downwards looking perspective on board the HALO research aircraft during this field campaign, aiming at the observation and characterization of clouds.

The combination of push-broom type spectral imaging sensors with two dimensional polarization resolving cameras offers new possibilities for cloud remote sensing. Using two dimensional images and stereographic techniques, the three dimensional structure of the cloud scene can be reconstructed (Kölling et al. 2019). The availability of a 3D model of the observed scene then allows to properly fuse passive observations from multiple sensors into a common data base. Additional information like cloud top height, cloud surface orientation, and an estimate of shadowed regions can aid previously available retrieval methods. Furthermore, the availability of polarization resolving images allows to strongly amplify the signal of single scattering processes. This and the large field of view of the two dimensional cameras largely improves the ability to derive cloud droplet size and width of the size distribution from the observation of cloudbows and glories (Mayer et. al. 2004, Pörtge 2019).

The poster will give an overview about the current instrument configuration and show data and first results from the EUREC⁴A field campaign.

References
Bony, S., Stevens, B., Ament, F. et al.: EUREC⁴A: A Field Campaign to Elucidate the Couplings Between Clouds, Convection and Circulation, Surv Geophys (2017) 38: 1529. https://doi.org/10.1007/s10712-017-9428-0

Ewald, F., Kölling, T., Baumgartner, A., Zinner, T., and Mayer, B.: Design and characterization of specMACS, a multipurpose hyperspectral cloud and sky imager, Atmos. Meas. Tech., 9, 2015–2042, https://doi.org/10.5194/amt-9-2015-2016, 2016.

Kölling, T., T. Zinner, B. Mayer, 2019, Aircraft-based stereographic reconstruction of 3-D cloud geometry, Atmos. Meas. Tech., 12, 1155-1166, https://doi.org/10.5194/amt-12-1155-2019, 2019.

Mayer, B., Schröder, M., Preusker, R., and Schüller, L.: Remote sensing of water cloud droplet size distributions using the backscatter glory: a case study, Atmos. Chem. Phys., 4, 1255–1263, https://doi.org/10.5194/acp-4-1255-2004, 2004.

Veronika Pörtge. Cloud Droplet Size Distributions from Observations of Glory and Cloudbow. Master’s thesis, Ludwig-Maximilians-Universität München, 11 2019.