April 5, 2021
ACTIVATE wrapped up its winter 2021 flight campaign with five joint research flights this past week (RF 57-61) capped off by a double-flight day on Friday (4/2) to capitalize on another cold air outbreak event. Those two flights included an increased number of dropsondes (~10 per flight) to get extensive temporal and spatial characterization of the vertical atmospheric structure as the cold air outbreak cloud field evolved during the day. Notable in the other flights last week was successful coordination with ASTER and CALIPSO overpasses in our flight region.
March 29, 2021
We executed a joint flight (RF 56) on Tuesday March 23rd on a day marked by fairly ‘clean’ conditions in terms of very low aerosol and cloud drop number concentrations in the marine boundary layer. Cloud fraction on this day was markedly lower than a typical cold air outbreak type of day, which is helpful for ACTIVATE which is aiming to generate statistics in a wide range of conditions associated with aerosols, clouds, and meteorology.
March 22, 2021
The previous week posed significant weather challenges but Saturday (March 20, 2020) did finally provide low clouds evolving in a cold air outbreak. Interesting features in that joint flight (Research Flight 55) were Asian dust residing aloft above the boundary layer clouds, in addition to an interesting layer of depolarizing aerosol right above clouds near the end of flight as observed by the HSRL-2; it is unclear what the source of that layer was, but data analysis with the Falcon data will help unravel those details.
March 15, 2021
ACTIVATE conducted four more successful joint flights (Research Flights 51-54) this past week. We characterized a variety of cloud conditions including post-frontal clouds associated with another cold air outbreak on Monday (March 8) in contrast to the following day (Tuesday March 9) where there was a sharp inversion with uniform cloud top heights and generally thin clouds. Flights this past week were marked by influence from local and regional burning emissions. The second of two flights on Friday (March 12) was coordinated with a CALIPSO overpass.
March 8, 2021
ACTIVATE executed three successful joint flights (Research Flights 48-50) this past week. On Thursday March 4th we coordinated our flight with a NASA A-Train overpass over an area with some scattered marine boundary layer clouds. The back-to-back flights on Friday March 5th served two objectives to capitalize on an excellent cold air outbreak event: (i) characterize the aerosol and meteorological characteristics upwind of the cloud field farther downwind; and (ii) characterize the evolution of the cloud field with the desire to capture the transition from overcast cloudy conditions to open cell structure. Noteworthy features in these flights were dust layers from long-range transport and significant new particle formation.
Febraury 5, 2021
ACTIVATE’s had its first joint flight of the winter 2021 campaign on February 3. We were successful to sample a transition from overcast stratocumulus clouds to broken cumulus clouds near our farthest southeast point of the flight track. There was extensive mixed-phase precipitation in areas closer to shore but pure liquid clouds farther offshore coinciding with the open cell cloud field. Although at low optical depth, an interesting aerosol layer was observed above 6 km that most likely was dust due to its depolarizing nature.
January 30, 2020
This past week ACTIVATE took to the skies again to begin our 2021 winter campaign. In contrast to last year, we started a bit earlier in the month of January to capitalize on a higher frequency of cold air outbreak events. Friday’s flights (January 29) were particularly ideal with both aircraft sampling along cloud streets aligned with the predominant wind direction coming from the north/northwest. We observed a transition from supercooled droplets to mixed phase precipitation with distance away from shore.