Abstract. Past studies have suggested that ozone in the troposphere has increased globally throughout much of 20th century due to increases anthropogenic emissions and transport. We show, by combining satellite measurements with a chemical transport model, during last four decades tropospheric does indeed indicate are global nature, yet still highly regional. Satellite from Nimbus-7 Earth Probe Total Ozone Mapping Spectrometer (TOMS) merged Aura Monitoring Instrument/Microwave Limb Sounder...

1998-2016 ozone trends in the lower stratosphere (LS) are examined using Modern-Era Retrospective Analysis for Research and Applications Version 2 (MERRA-2) related NASA products. After removing biases resulting from step-changes MERRA-2 observations, a discernible negative trend of -1.67±0.54 Dobson units per decade (DU/decade) is found 10-km layer above tropopause between 20°N 60°N. A weaker but statistically significant -1.17±0.33 DU/decade exists 50°S 20°S. In Tropics, positive seen 5-km...

Abstract Eight years of ozone measurements retrieved from the Ozone Monitoring Instrument and Microwave Limb Sounder, both on EOS Aura satellite, have been assimilated into Goddard Earth Observing System Version 5 (GEOS‐5) data assimilation system. This study evaluates this product, highlighting its potential for science. The impact observations GEOS‐5 system is explored by examining spatial distribution observation‐minus‐forecast statistics. Independent are used product validation....

This study examines the relationship between extratropical cross‐tropopause fluxes of mass and ozone. The adiabatic diabatic components net are also compared. rate change in lowermost stratosphere flux across 380 K isentropic surface used to determine tropopause framework a global circulation model. is calculated from heating at tropopause, component determined by difference fluxes. Consistent ozone fields obtained driving Goddard Chemistry Transport Model with meteorological output model...

Abstract Measurements from the Ozone Monitoring Instrument (OMI) and Microwave Limb Sounder (MLS), both on board Aura spacecraft, have been used to produce daily global maps of column profile ozone since August 2004. Here we compare evaluate three strategies obtain tropospheric stratospheric OMI MLS measurements: trajectory mapping, direct retrieval, data assimilation. Evaluation is based an assessment that includes validation using ozonesondes comparisons with Global Modeling Initiative...

Abstract The El Niño–Southern Oscillation (ENSO) and the Quasi‐Biennial (QBO) are natural sources of ozone variability in tropical midlatitude upper troposphere lower stratosphere. Regional tropospheric variations have previously been attributed to ENSO‐ QBO‐induced changes stratosphere‐troposphere exchange around subtropical jets (STJs). We use Goddard Earth Observing System Data Assimilation analyses Ozone Monitoring Instrument Microwave Limb Sounder data mapped a STJ coordinate examine...

Abstract. We use GEOS-5 analyses of Ozone Monitoring Instrument (OMI) and Microwave Limb Sounder (MLS) ozone observations to investigate the magnitude spatial distribution El Niño Southern Oscillation (ENSO) influence on tropospheric column (TCO) into middle latitudes. This study provides first explicit spatially resolved characterization ENSO demonstrates coherent patterns teleconnections impacting TCO in extratropics. The response is evaluated characterized by both variance explained...

The Goddard Earth Observing System, version 4 general circulation model (GCM) is used to examine the influence of sea surface temperatures (SSTs) on stratospheric and extratropical stratosphere‐troposphere exchange (STE). simulation uses observed SSTs from 1949 1998 at lower boundary. atmospheric greenhouse gas (GHG) burden interannually constant artificially decouple radiative SST forcing. A stronger gradient tropics through middle latitudes results in a greater meridional temperature...

Abstract. We examine the relative contribution of processes controlling interannual variability (IAV) tropospheric ozone over four sub-regions southern hemispheric maximum (SHTOM) a 20-year period. Our study is based on hindcast simulations from National Aeronautics and Space Administration Global Modeling Initiative chemistry transport model (NASA GMI-CTM) stratospheric chemistry, driven by assimilated Modern Era Retrospective Analysis for Research Applications (MERRA) meteorological...

Abstract. The NASA Global Modeling Initiative has developed a combined stratosphere/troposphere chemistry and transport model which fully represents the processes governing atmospheric composition near tropopause. We evaluate ozone distributions tropopause, using two high vertical resolution monthly mean profile climatologies constructed with ozonesonde data, one by averaging on pressure levels other relative to thermal At is high-biased in SH tropics NH midlatitudes ~45% 4° latitude ×5°...

The extratropical stratosphere–troposphere exchange (STE) of ozone from 2005 to 2010 is estimated by combining Microwave Limb Sounder observations and MERRA reanalysis meteorological fields in an established direct diagnostic framework. multiyear mean STE 275 Tg yr −1 214 the Northern Southern Hemispheres, respectively. year‐to‐year variability greater Hemisphere, where difference between highest lowest annual flux 15% compared with 6% Hemisphere. Variability lower stratospheric net mass...

Abstract. In this study we use ozone and stratospheric tracer simulations from the high-resolution (0.5∘×0.5∘) Goddard Earth Observing System, Version 5 (GEOS-5), in a replay mode to impact of on tropospheric interannual variability (IAV). We these conjunction with ozonesonde measurements 1990 2016 during winter spring seasons. The include (StratO3) aid evaluation IAV at different altitudes locations. model is good agreement observed variation ozone, except for post-Pinatubo period...

The role of dry stratospheric air descending to low and middle tropospheric levels in a severe weather outbreak the midwestern United States is examined using NCEP Eta model output, Rapid Update Cycle (RUC) analyses, Earth probe Total Ozone Mapping Spectrometer (EP/TOMS) total ozone data. While was not found play direct convection, backward trajectories show descended 800 hPa just west convection. Damaging surface winds associated with thunderstorms also occurred region greatest descent....

Observed co‐variations between polar total column ozone and the Southern Hemisphere Annular Mode (SAM) during 1962–2004 are presented evaluated in a chemistry‐climate model (CCM). Results show that austral spring variability at South Pole is significantly related to SAM, perhaps up four months later; this relationship only seen simulations include depletion. The SAM also linked following late – early summer over cap, since both respond wave‐driving of stratosphere. Overall, CCM captures many...

Observations from long-term ozonesonde measurements show robust variations and trends in the evolution of ozone middle upper troposphere over Réunion Island (21.1°S, 55.5°E) June-August. Here we examine possible causes observed variation at using hindcast simulations by stratosphere-troposphere Global Modeling Initiative chemical transport model (GMI-CTM) for 1992-2014, driven assimilated Modern-Era Retrospective Analysis Research Applications (MERRA) meteorological fields. is edge...

High‐resolution (∼40 km) along‐track total column ozone data from the Total Ozone Mapping Spectrometer (TOMS) instrument are compared with a high‐resolution mesoscale numerical model analysis of an intense cyclone in Midwestern United States. increased by ∼100 DU (nearly 38%) as TOMS passed over associated tropopause fold region. Complex structure is seen meteorological fields and compares well observations. support showing that stratospheric descent was confined to levels above ∼600 hPa;...

A new method of estimating the downward ozone flux across midlatitude tropopause is introduced. The algorithm derives estimate from total column observations. Vertical information given by analysis potential vorticity fields. This yields an annual 500 ± 140 Tg yr −1 stratospheric injection into northern hemisphere, troposphere. exhibits expected spring maximum and autumn minimum. distribution cross‐tropopause transport latitude consistent with seasonal frequency baroclinic systems. also...

We use the high‐resolution dynamic limb sounder (HIRDLS) high‐vertical resolution ozone profiles in northern hemisphere lower stratosphere to examine meridional transport out of tropics. focus on February 2005–2007 when there are differences dynamical background due states quasi‐biennial oscillation and polar vortex. HIRDLS data reveal a large number low laminae that have characteristics tropical air at midlatitudes. More observed 2006 than 2005 or 2007. Because can form, move tropics,...

Abstract. Statistical relationships between the variability of area covered by double tropopause events (DTs), strength tropical upwelling, total column ozone and lower stratospheric water vapour are analyzed. The QBO ENSO signals in upwelling as well their influence on statistical also presented. analysis is based both reanalysed data (ERA-Interim) satellite data. Significant anticorrelations were found DTs midlatitudes Northern Hemisphere. This relationship confirmed a large positive...

The downward flux of ozone across the midlatitude (30°–60°) tropopause is calculated using changes in potential vorticity (PV) and a statistical relationship between PV flux. This approach separates dynamical aspects transport from seasonal cycle lowermost stratosphere. Northern Hemisphere (NH) larger (∼24%) than that Southern (SH) during year 2000. SH total horizontal area exchange equal to or slightly greater NH throughout an annual cycle. mean parcels near are also similar SH, suggesting...

On 26 January 2006, the High Resolution Dynamic Limb Sounder (HIRDLS) observed low mixing ratios of ozone and nitric acid in a ∼2 km layer near 100 hPa extending from subtropics to 55°N over North America. The subsequent evolution is simulated with Global Modeling Initiative model substantiated HIRDLS observations. Air transported poleward 80°N. Although there evidence extratropical air, much tropical intrusion returns subtropics. This study demonstrates that GMI resolve thin events....

Abstract. Past studies have suggested that ozone in the troposphere has increased globally throughout much of 20th century due to increases anthropogenic emissions and transport. We show by combining satellite measurements with a chemical transport model during last four decades tropospheric does indeed indicate are global nature, yet still highly regional. Satellite from Nimbus-7 Earth Probe Total Ozone Mapping Spectrometer (TOMS) merged Aura Monitoring Instrument/Microwave Limb Sounder...

The impact of changes in the abundance greenhouse gases (GHGs) on evolution tropospheric ozone (O 3 ) between 1960 and 2005 is examined using a version Goddard Earth Observing System chemistry‐climate model (GEOS CCM) with combined troposphere‐stratosphere chemical mechanism. Simulations are performed to isolate relative role increases methane (CH 4 stratospheric depleting substances (ODSs) O . GHGs (CO 2 , N O, CH ODSs) cause around 1–8% zonal‐mean tropics northern extratropics, but...

We present evidence for stratospheric mass transport into, and remaining in, the troposphere in an intense midlatitude cyclone. Mesoscale forecast model analysis fields from Analysis Prediction System were compared with total ozone observations Total Ozone Measurement Spectrometer. Coupled parcel back trajectory calculations, analyses suggest that two mechanisms contributed to exchange: (1) A region of dynamically induced exchange occurred on cyclone's southern edge. Parcels originally...