This slide shows an ensemble of the Volume Mixing Ratio (VMR) profiles of CO along the path of the RV Polarstern along the Atlantic Ocean. The VMR profiles were retrieved from two cruises during the summer months of the northern and southern hemisphere. The first cruise took place in Dec. 1999 to Jan. 2000 (southern hemisphere summer) from Bremerhaven, Germany to Antarctica. The second cruise took place in June 2000 (northern hemisphere summer) from Bremerhaven to Ny-Alesund.
The collected profiles show a “slice” of the atmospheric CO mixing ratios along the path of the Polarstern from 79°N to 70°S and from about 2 km to 15 km. (The VMR color codes have the same values as the color bar on slide 5. With blue corresponding to about 20 ppb and red to about 160ppb to 210 ppb).
Backward trajectories, are also plotted with the following height levels:
- Green lines: 700 hPa (2.6 km)
- Blue lines: 300 hPa (8.7 km)
- Magenta lines: 140 hPa (14.2 km)
- (source: HYSPLIT trajectories for cruise 1999-2000.).
White lines represent the coastlines of the different continents and countries. The red dots represent fire counts taken from MODIS web fire mapper (»http://maps.geog.umd.edu/default.asp)
Note the region with high CO VMRs near the equator (indicated by the reddish color). According to the trajectories, air parcels ending up in this region originated near areas with high fire counts.
The relatively CO rich northern hemisphere could also be distinguished. The lower troposphere of the southern hemisphere is relatively clean, however high CO VMRs have been detected at 10 km-15 km south of 20°S. Backward trajectories indicate that this high CO may have originated from the south American continent. Convective transport of polluted air from the surface of the continent to high altitudes above the Atlantic most likely explains the high CO enhancements in the upper troposphere
