A Summary of the ICARTT Measurement Comparison Between the NASA DC-8 and FAAM BAe-146

One of the objectives of the ICARTT (International Consortium on Atmospheric Research on Transport and Transformation) experiment during the summer of 2004 was to examine the transformation of pollutants as they were transported across the North Atlantic. To enable this, measurements were made on several platforms across the North Atlantic, and at times it was attempted to resample air previously encountered by an upstream platform (Lagrangian experiment). To treat all the data collected on the different platforms as a single database and in particular to interpret the Lagrangian measurements it is essential to know how measurements on each platform compare. To facilitate this, a number of comparisons were made between pairs of platforms to create a chain of comparisons across all platforms. The comparison between the measurements on the NASA DC-8 and the FAAM BAe-146 was one such comparison and provides links to the NOAA WP-3D and DLR Falcon. The comparison flight between the NASA DC-8 and the FAAM BAe-146 was carried out on July 28, 2004, following a coordinated plan devised by both INTEX and ITOP science teams. The aircraft rendezvoused west of the Azores (~ 38° North, ~ 38° West) and both planes flew in wing-tip to wing-tip formation for approximately 70 minutes, performing level runs at 22,000 ft, 12,000 ft and 1,000 ft in cloud free air. This allowed both aircraft to sample the same air masses and compare the common measurements quantitatively over an altitude range of 21,000 ft. The species presented here include O3, CO, C2H6, C2H4, C2H2, benzene, toluene, CH2O, acetone, CH3OH, peroxide, total particle concentration, particulate sulfate, nitrate and meteorological parameters, i.e., pressure, ambient temperature, and dew point temperature.