In its first marine deployment, the DOE Atmospheric Radiation Measurement (ARM) Program second mobile facility (AMF2) crossed the Pacific Ocean between Los Angeles and Honolulu repeatedly from October 2012 to September 2013. The goal of these travels was to improve the way global climate models represent cloud transformations from one type to another (stratocumulus to cumulus). A lack of data on these transformations has limited the models' abilities to understand and predict cloud effects on climate.
EVS atmospheric scientists designed the AMF2 and devoted four years to developing it, operating it, and then modifying the instruments and their packaging for the shipboard deployment. EVS was responsible for AMF2 management and operations until March 2015.
The AMF2 is housed mostly in converted shipping containers. Adaptations for the Pacific voyage included construction of new instrument mounts, adding protection from the elements, economizing on shipboard space, and strengthening data intake capabilities and archival support. A stabilized platform was added to keep an essential cloud-probing radar pointing at the zenith while the ship rolls and pitches in the Pacific waves.
The home of the AMF2 during its yearlong voyage was the Horizon Lines containership Spirit, which traversed a scheduled shipping route between California and Hawaii approximately 25 times during the year. Making continuous observations along this path every two weeks allowed the AMF2 to gather a consistent, detailed data set over all seasons. The AMF2 instruments were installed while Spirit was in port in Los Angeles in September 2012.
The AMF2 route crossed a region of the ocean in which low-lying marine boundary layer clouds are abundant. Such clouds are constantly undergoing transformations and influencing Earth's climate by reflecting sunlight and affecting radiative interactions between the atmosphere and the ocean. These variable cloud conditions became the ideal laboratory for AMF2 to gather the data needed to improve global climate models. For this purpose, AMF2 data are superior to what was available previously. The AMF2 data are far more detailed than satellite observations, and they cover a much longer period than the previous marine measurements.
The route Spirit follows also coincided with the line of study in a DOE project called MAGIC. MAGIC is comparing the results from major climate models. The AMF2 data will help the modeling effort by providing constraints, validation, and support. MAGIC is a collaboration between Brookhaven National Laboratory, Lawrence Livermore National Laboratory, the National Aeronautics and Space Administration, Stony Brook University, and other universities and private consultants. The AMF2, which was crucial to gathering the data needed for MAGIC, was operated and maintained by EVS atmospheric scientists; they sailed the Pacific with the mobile laboratory in two-week shifts.
For the science community, the data gathered by the AMF2 will improve understanding of clouds, aerosols, Earth's energy and water balance, and the interactions among these entities in the marine environment. The AMF2 provided a data set of unequaled quality and richness for evaluating and improving climate models. The data was placed in the ARM Data Archive for use by anyone who is interested.
For Horizon Lines, collaborating in the MAGIC campaign was an opportunity to contribute to improvements in both the safety and economy of marine shipping. Pete Strohla, Vice President of Operating Services, said, “Our hope is that better understanding of climate change will facilitate more accurate weather forecasting, which in turn will help our industry plan safer and more fuel-efficient vessel routes.”
MAGIC – the Marine ARM GPIC Investigation of Clouds – is a project of the DOE Office of Science. GPIC stands for GCSS Pacific Cross-section Intercomparison; GPIC is a working group of the GCSS. The GCSS (the GEWEX Cloud Systems Study) is an aspect of GEWEX, which in turn is a core project of the World Climate Research Programme.
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