In situ vertical profiles of black carbon aerosol over the Pacific, Arctic, and Antarctic Regions (80°N to 67°S Latitudes)

In three weeks of January 2009, the NSF /NCAR GV research aircraft flew the HIAPER Pole-to-Pole Observations (HIPPO) mission, with a Single-Particle Soot Photometer (SP2) on board. The SP2 characterized the mass of refractory black carbon (rBC) in individual aerosol particles measured in situ over a total of 138 vertical profiles primarily between 0.3 and 8 km AMSL from 80N to 67 S, including some profiles to 13 km. These measurements of rBC, which are unprecedented in scope, were primarily obtained in the remote central and eastern Pacific, allowing sampling far from sources. Air of extremely low rBC loadings (rBC mass < 0.05 ng/kg air) was detected in both the southern hemisphere lower troposphere and the tropical middle troposphere. Enhanced BC loadings were observed at high northern latitudes associated with Arctic haze and at northern midlatitudes in the central Pacific in air masses tracing back to northern Asia. These results form a powerful constraint on global model treatments of rBC lifetime and transport. A comparison will be made between observed [zonal average is the mean on a latitude circle; I think you mean binned in longitude] profiles and those generated from the AEROCOM suite of global models.