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ACLOUD 2017: Arctic Amplification: Fluxes in the Cloudy Atmospheric Boundary Layer

Start date: 17-05-2017 - End date: 08-07-2017

Status: Not confirmed

Open to sharing: Yes

Confidential: No

Transnational Access: No

Open to training: Yes

Grounded / Maintenance: No


Aircraft name: POLAR 5 - AWI

Airport: Longyearbyen, Svalbard

Project description

Project theme: Measurements of turbulent and radiative energy fluxes above, in and below Arctic boundary layer clouds for differentmeteorological, sea ice and aerosol conditions

Project abstract: The main objectives of this project are (i) to measure energy fluxes in the atmospheric boundary layer (ABL) over polar sea ice in cloudy and clear-sky conditions, (ii) to investigate their dependence on aerosol particle properties and vertical distribution, and (iii) to compare the energy fluxes with respective model results. The analysis of the data of this project will help to understand the role of low- level Arctic clouds in the energy budget of the ABL. The program is closely linked with the planned DFG SFB/Transregio project on Arctic amplification (acronym (AC)3, Arctic Amplification: Climate Relevant Atmospheric and Surface Processes, and Feedback, pre-proposal submitted to DFG in June 2014). The instrumented Polar 5 and Polar 6 aircraft will be used to perform the measurements of turbulent and radiation fluxes as a function of cloud cover, sea ice characteristics, synoptic forcing, and geographic position with a focus on the vertical distribution of the fluxes. Both aircraft will be equipped with remote sensing (Polar 5) and in-situ (mainly on Polar 6) instrumentation. Measurements based on the combination of turbulence and radiation, as well as microphysical probes, Lidar, Radar and microwave sensors for aerosol and cloud properties will improve our understanding of the interaction between cloud characteristics and turbulence and of their role for the ABL energy budget. The campaign will be closely coordinated with a proposed cruise of RV Polarstern (PASCAL, Physical feedbacks of Arctic PBL, Sea ice, Cloud And Aerosol) that will be used as a platform for surface based observations using a large suite of meteorological instrumentation (installed partly on the ship and on sea ice) to determine e.g., the surface energy budget. Due to the close link to (AC)3 and PASCAL several groups from different German research institutes (Universities of Bremen, Köln, and Leipzig, TROPOS Leipzig, AWI Bremerhaven and AWI Potsdam) will benefit from the measurement program although not all of them will directly participate in the measurements.

Science context: Atmospheric boundary layer, polar regions Cloud physics, Ocean-Atmosphere interactions, Radiation

Measurements to be made by aircraft:  Airborne observations of meteorological and sea ice parameters supplementing shipborne observations of the atmospheric profile and surface energy budget by RV Polarstern during the research cruise PASCAL;  Measurements characterizing the mean state of the atmospheric boundary layer during late spring/early summer (temperature, humidity, wind components);  Turbulent fluxes (vertical profiles based on horizontal, vertically staggered flight sections);  Aerosol number and mass size distributions;  Cloud particle shape, concentration, size distribution, scattering phase function;  Aerosol and meteorological profiles up to 3 km altitude;  Spectral upward and downward radiances and broadband irradiances;  Polarized upward radiance and imagery;  Retrieval of cloud optical thickness and effective radius maps based on hyperspectral imaging;

Flights (number and patterns): 15-25 flights, max. 160 h

Instruments: None

Scientific contact

Name: None