Sensitivity of Global Modeling Initiative chemistry and transport model simulations of radon-222 and lead-210 to input meteorological data

摘要

We have used the Global Modeling Initiative chemistry and transport model tosimulate the radionuclides radon-222 and lead-210 using three different setsof input meteorological information: 1. Output from the Goddard Space FlightCenter Global Modeling and Assimilation Office GEOS-STRAT assimilation; 2.Output from the Goddard Institute for Space Studies GISS II' generalcirculation model; and 3. Output from the National Center for AtmosphericResearch MACCM3 general circulation model. We intercompare these simulationswith observations to determine the variability resulting from the differentmeteorological data used to drive the model, and to assess the agreement ofthe simulations with observations at the surface and in the uppertroposphere/lower stratosphere region. The observational datasets we use areprimarily climatologies developed from multiple years of observations. Inthe upper troposphere/lower stratosphere region, climatologicaldistributions of lead-210 were constructed from ~25 years of aircraftand balloon observations compiled into the US Environmental MeasurementsLaboratory RANDAB database. Taken as a whole, no simulation stands out assuperior to the others. However, the simulation driven by the NCAR MACCM3meteorological data compares better with lead-210 observations in the uppertroposphere/lower stratosphere region. Comparisons of simulations made withand without convection show that the role played by convective transport andscavenging in the three simulations differs substantially. These differencesmay have implications for evaluation of the importance of very short-livedhalogen-containing species on stratospheric halogen budgets.