NOGAPS-ALPHA model simulations of stratospheric ozone during the SOLVE2 campaign

[摘要] This paper presents three-dimensional prognostic O₃ simulationswith parameterized gas-phase photochemistry from the new NOGAPS-ALPHA middle atmosphereforecast model. We compare 5-day NOGAPS-ALPHA hindcasts ofstratospheric O₃ with satellite andDC-8 aircraft measurements for two cases duringthe SOLVE II campaign: (1) the cold, isolated vortex during 11-16 January 2003;and (2) the rapidly developing stratospheric warming of 17-22 January 2003.In the first case we test three different photochemistry parameterizations.NOGAPS-ALPHA O₃ simulations using the NRL-CHEM2D parameterization give thebest agreement with SAGE III and POAM III profile measurements.5-day NOGAPS-ALPHA hindcasts of polar O₃ initialized with the NASA GEOS4 analyses produce better agreementwith observations than do the operational ECMWF O₃ forecasts of case 1.For case 2, both NOGAPS-ALPHA and ECMWF114-h forecasts of the split vortex structure in lower stratospheric O₃ on 21 January 2003 show comparable skill. UpdatedECMWF O₃ forecasts of this event at hour 42 display markedimprovement from the 114-h forecast; corresponding updated 42-hourNOGAPS-ALPHA prognostic O₃ fields initialized with theGEOS4 analyses do not improve significantly. When NOGAPS-ALPHAprognostic O₃ is initialized with the higher resolution ECMWF O₃ analyses, the NOGAPS-ALPHA 42-hour lower stratospheric O₃ fieldsclosely match the operational 42-hour ECMWF O₃ forecast of the 21 January event.We find that stratospheric O₃ forecastsat high latitudes in winter can depend on both model initialconditions and the treatment of photochemistry over periods of 1-5 days.Overall, these results show that the new O₃ initialization,photochemistry parameterization,and spectral transport in the NOGAPS-ALPHANWP model can provide reliable short-range stratospheric O₃ forecastsduring Arctic winter.

[学科分类] 大气科学