The overarching goal of ARCSIX is to quantify the contributions of surface properties, clouds, aerosol particles, and precipitation to the Arctic summer surface radiation budget and sea ice melt during the entire melt season (May through mid-August). It encompasses three main science questions and one objective:
- Science Question 1 (Radiation): What is the impact of the predominant summer Arctic cloud types on the radiative surface energy budget?
- Science Question 2 (Cloud Life Cycle): What processes control the evolution and maintenance of the predominant cloud regimes in the summertime Arctic?
- Science Question 3 (Sea Ice): How do the two-way interactions between surface properties and atmospheric forcings affect the sea ice evolution?
- Remote Sensing and Modeling Objective: Enhance our long-term space-based monitoring and predictive capabilities of Arctic sea ice, cloud, and aerosols by validating and improving remote sensing algorithms and model parameterizations in the Arctic.
To accomplish ARCSIX's science and objectives, three aircraft flew in coordination. Two aircraft, the NASA WFF P-3 and the Spec, Inc. LearJet, acquired in-situ aerosol particle, cloud, atmospheric, and surface properties along with radiation below, above, and inside the cloud layer, while the third, the NASA LaRC G-III, served as a bridge to satellite observations by surveying with heritage and novel remote sensing instruments from above. This provided the required near-simultaneous characterization of radiative fluxes, surface, and cloud properties to address Science Questions 1 and 3. Statistical sampling of cloud vertical structure, temperature, and humidity profiles, complemented by simultaneous remote sensing, addressed Science Question 2 and the Remote Sensing and Modeling Objective. To extrapolate the spatially and temporally limited field observations beyond ARCSIX itself, the ARCSIX airborne data were integrated with satellite remote sensing observations and model simulations. Targeted sampling of distinct regimes defined by cloud type and the associated prevailing surface and meteorological conditions enabled more valuable combinations of airborne and satellite remote sensing observations and model simulations. This combination of observations and model simulations pushed the performance of remote sensing algorithms towards more realism for various conditions. It culminated in a more realistic depiction of radiative processes, cloud life cycles, and sea ice evolution in climate, regional forecast, and process models.
During the two Summer 2024 deployments (May 24 to June 17 and July 22 to August 17, 2024), the ARCSIX project flew a combined 31 science flights (15 P-3 and 16 G-III), accumulating a combined total of 159 research flight hours.
