Smart tetroons for Lagrangian air-mass tracking during ACE 1

A series of "smart" tetroons was released from shipboard during the recent ACE 1 field experiment designed to monitor changes in the sulfur budget in a remote marine boundary layer (MBL) south of Tasmania, Australia. The smar t tetroons were designed at NOAA Air Resources Laboratory Field Research Di vision to provide air parcel tracking information. The adjective smart here refers here to the fact that the buoyancy of the tetroons automatically ad justs through the action of a pump and valves when the tetroon travels vert ically outside a range of pressures set prior to tetroon release. The smart tetroon design provides GPS location, barometric pressure, temperature, re lative humidity, and tetroon status data via a transponder to the NCAR C-13 0 research aircraft flying in the vicinity of the tetroons. In this paper w e will describe (1) the design and capability of the smart tetroons and the ir performance during the two Lagrangian experiments conducted during ACE 1 , (2) the synoptic context of the Lagrangians, including the origin of the air parcels being tracked, and (3) the results of trajectory predictions de rived from the National Center for Environmental Prediction (NCEP) Global S pectral Model (GSM) and Australia's Commonwealth Scientific and Industrial Research Organization (CSIRO) Division of Atmospheric Research (DAR) limite d-area model.