Measurements and steady state calculations of OH concentrations at Mauna Loa Observatory

In situ OH measurements were made as part of the spring and summer intensives of Mauna Loa Observatory Photochemistry Experiment (MLOPEX 2). These measurements provided an opportunity to compare measured OH concentrations with those predicted by steady state models which use the many other measurements which made up MLOPEX 2 as input parameters. These models thus provide a highly specific real-time view of the environment in which OH was being measured. Both short- and long-term variations of OH are discussed along with their relation to changes in sources and sinks. In general, agreement between measured and modeled OH concentrations is good during periods when free tropospheric air masses, typically downslope, were present. During periods when certain types of upslope boundary layer air dominated the measurement site, however, measured OH concentration averaged about a factor of 2 lower than the model predictions. Possible reasons for the latter differences are suggested, such as unidentified sinks in the boundary layer air.

[1]  D. Tanner,et al.  Measurement of the gas phase concentration of H2SO4 and methane sulfonic acid and estimates of H2SO4 production and loss in the atmosphere , 1993 .

[2]  Yi-Leng Chen,et al.  Diurnal Variation of Surface Airflow and Rainfall Frequencies on the Island of Hawaii , 1994 .

[3]  T. Gerlach,et al.  Volatile budget of Kilauea volcano , 1985, Nature.

[4]  M. Molina,et al.  Chemical kinetics and photochemical data for use in stratospheric modeling , 1985 .

[5]  D. Tanner,et al.  Ions in oceanic and continental air masses , 1991 .

[6]  P. Mcmurry,et al.  Measurement of Expected Nucleation Precursor Species and 3–500-nm Diameter Particles at Mauna Loa Observatory, Hawaii , 1995 .

[7]  D. Tanner,et al.  Ion-assisted tropospheric OH measurements , 1991 .

[8]  Jerald W. Harder,et al.  Intercomparison of tropospheric OH and ancillary trace gas measurements at Fritz Peak Observatory, Colorado , 1994 .

[9]  D. Ehhalt,et al.  Comparison of the Tropospheric Concentration of OH with Model Calculations , 1992 .

[10]  P. Hess,et al.  Trajectories and related variations in the chemical composition of air for the Mauna Loa observatory during 1991 and 1992 , 1996 .

[11]  Roy Rasmussen,et al.  On the Dynamics of Hawaiian Cloud Bands: Island Forcing , 1988 .

[12]  C. J. Hahn,et al.  Meteorological influences during MLOPEX , 1992 .

[13]  E. Robinson,et al.  The Mauna Loa Observatory photochemistry experiment , 1992 .

[14]  D. Tanner,et al.  Present OH measurement limits and associated uncertainties , 1995 .

[15]  G. Mount,et al.  An Intercomparison of Tropospheric OH Measurements at Fritz Peak Observatory, Colorado , 1992, Science.