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Concentration gradients and dry deposition of nitric acid vapor at the Mauna Loa Observatory, Hawaii

1993; American Geophysical Union; Volume: 98; Issue: D7 Linguagem: Inglês

10.1029/93jd00817

2156-2202

Gangwoong Lee, Liangzhong Zhuang, B. J. Huebert, Tilden Meyers,

Atmospheric and Environmental Gas Dynamics

From August 14 to September 5, 1991, we measured the mixing ratio of nitric acid vapor and several aerosol species (nitrate, sulfate, ammonium and sodium) at three heights (2 m, 10 m and 30 m) at the Mauna Loa Observatory. Well‐defined logarithmic gradients of temperature and HNO 3 vapor were measured throughout the experiment, indicating rapid HNO 3 vapor deposition to the ground. Measured dry deposition velocities for HNO 3 vapor ranged from 0.27 to 4 cm s −1 . The collection efficiency for HNO 3 vapor varied with sampler location and orientation on the sampling tower, due to concentration depletion by the tower or the sampler itself. We found that our long‐term samplers at 8 m may underestimate free tropospheric HNO 3 mixing ratios by about 20% due to dry deposition.