
Now we are done, that was our last scheduled measurement flight of CARRIBA 2011 with the helicopter CFNHG carrying ACTOS and SMART-Helios. Many thanks to all contributors and the people who gave me the opportunity to be a part of this project!
Thus we went there and dipped ACTOS into them. Some were really thick up to more than 8000 ft and contained a lot of liquid water. We continued cloud chasing for approximately 40 min in height between 5000 and 6000 ft. Before going back to Concorde helipad we went below cloud level for another short horizontal leg. This layer was obviously influenced by biomass burning, the particle concentrations were relatively high and we could also smell it.
After all, another interesting flight giving probably interesting results about the influence of transported dust on trade wind cumulus clouds.
A typical size distribution of marine aerosol was measured on April the 9th at the ground-based measurement station at Ragged Point (red). The Aitken and accumulation mode, seperated by the so called Hoppel-minimum can be seen in the Figure. On April the 15th a Saharan dust layer with a maximum total number concentration at 2-4 km height was situated above the measurement region. Through synoptic scale advection of these Saharan dust to the measurement region since 14/04/2011 and following downmixing of those particles into the boundary layer, the shape of the number size distribution has changed. Compared to the typical measured number concentration in this marine region (red), the entrainment of the Saharan dust causes an increased number concentration (black) and the typical shape of the Hoppel-minimum gets almost lost.
To compare with yesterdays flight we went down below cloud level to 1100 ft. We flew a horizontal leg there for approximately 7 min followed by vertical profiles through the transition layer: between 1100 and 2500 ft. Since there was still flight time left, we flew through some more clouds and this time the second higher cloud layer was almost gone. After another horizontal leg within 2500 ft between clouds we flew back to the airport below cloud base.