Top ARM Accomplishment: Improvements in Aircraft Campaigns
ARM has mounted aircraft campaigns at three of its five permanent sites, and at some of its mobile facility sites, in order to do more in-depth process studies of the clouds most relevant to climate. Several campaigns are worthy of special note. First, ARM resolved the biggest debate ever to occur in the atmospheric radiation community, concerning claims of “enhanced shortwave cloud absorption” in the 1990s, by sponsoring two extensive aircraft campaigns (ARESE I and II). The ARESE campaigns strongly pushed the community into the study of 3D effects, leading directly to an ARM-sponsored book on 3D cloud radiation – the first of its kind. ARESE also identified and solved a heretofore-unknown infrared-loss problem in surface radiometers that led directly to improved surface radiation measurements worldwide. Second, ARM conducted two groundbreaking studies of aerosol-cloud interactions (M-PACE and ISDAC) in the Arctic; M-PACE spawned a GCSS intercomparison among 17 models — the maximum for any field campaign, ever.
ARM also brought radical innovations to aircraft campaigns. In the early 1990s, ARM was the first program ever to employ a UAV (Unmanned Aerial Vehicle) for atmospheric research, and was the first to fly a UAV for 24 hours, a full diurnal cycle. For seven years in the 2000s, ARM flew a single-engine Cessna several times a week to create the longest aerial dataset about aerosol ever gathered. Recently, ARM invented a new kind of aircraft campaign lasting six months or more, and completed two such campaigns in 2009 and 2010.