Comparison of Global-Scale Lagrangian Transport Properties of the NCEP Reanalysis and CCM3

Bowman, Kenneth P.; Erukhimova, Tatiana

doi:10.1175/1520-0442(2004)017<1135:cogltp>2.0.co;2

Cited by 26 publications

(37 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A number of studies have shown impediments to transport (i.e., transport barriers) between the extra-tropics and the tropics [Bowman and Carrie, 2002;Bowman and Erukhimova, 2004;Hess, 2005;Pierrehumbert and Yang, 1993]. These barriers imply that air within the mid-latitudes tends to recirculate within the mid-latitude region, and air within the tropics and subtropics tends to recirculate within the tropics and subtropics.…”

Section: General Circulation Regimessupporting

confidence: 85%

“…Thus, baseline concentrations at mid-latitude sites are most immediately affected by mid-latitude emissions, with a much smaller contribution from tropical sources. Equator-ward transport between the extra-tropics and tropics occurs primarily in shallow flow near the Earth"s surface associated with the equator-ward branch of the Hadley circulation, and often occurs behind cold fronts [Bowman and Carrie, 2002;Bowman and Erukhimova, 2004]. The poleward return-flow occurs in a more diffuse circulation in the upper troposphere associated with the upper branch of the Hadley cell (Figure 1.7).…”

Section: General Circulation Regimesmentioning

confidence: 99%

“…Therefore, poleward moving air tends to ascend, while equator-ward moving air tends to sink. Mid-latitude meridional stirring occurs along constant potential temperature surfaces on timescales up to 10 days [Bowman and Carrie, 2002;Bowman and Erukhimova, 2004]. Transport along potential temperature surfaces that intersect the surface of the Earth occurs primarily through the action of mid-latitude cyclones [Hess, 2005].…”

Section: General Circulation Regimesmentioning

confidence: 99%

See 2 more Smart Citations

Emission inventories and projections

Streets¹,

Aardenne²

2010

Air Pollution Studies

View full text Add to dashboard Cite

Section: General Circulation Regimessupporting

confidence: 85%

Section: General Circulation Regimesmentioning

confidence: 99%

Section: General Circulation Regimesmentioning

confidence: 99%

See 1 more Smart Citation

Emission inventories and projections

Streets¹,

Aardenne²

2010

Air Pollution Studies

View full text Add to dashboard Cite

“…Our method is not suitable to diagnose redistribution of tracers within the source region and recirculation back into the source region). Horizontally, we divide the earth surface into three equalarea latitude bands called "north" (N), "tropics" (T) and "south" (S), following Bowman and Carrie (2001); Bowman and Erukhimova (2004). "North" refers to the region north of 19 • N, the region south of 19 • S is "south" and the region in the latitude bands in-between 19 • N and 19 • S is "tropics".…”

Section: Experiments Descriptionmentioning

confidence: 99%

Sensitivity of tracer transport to model resolution, prescribed meteorology and tracer lifetime in the general circulation model ECHAM5

2010

View full text Add to dashboard Cite

Abstract. Atmospheric transport of traces gases and aerosols plays an important role in the distribution of air pollutants and radiatively active compounds. For model simulations of chemistry-climate interactions it is important to know how the transport of tracers depends on the geographical resolution of the general circulation model. However, this aspect has been scarcely investigated until now. Here, we analyse tracer transport in the ECHAM5 general circulation model using 6 independent idealized tracers with constant lifetimes, which are released in two different altitudes at the surface and in the stratosphere, respectively. Model resolutions from T21L19 to T106L31 were tested by performing multi-annual simulations with prescribed sea surface temperatures and sea ice fields of the 1990s. The impacts of the tracer lifetime were investigated by varying the globally uniform exponential decay time between 0.5 and 50 months. We also tested the influence of using prescribed meteorological fields (ERA40) instead of climatological sea surface temperature and sea ice fields. Meridional transport of surface tracers decreases in the coarse resolution model due to enhanced vertical mixing, with the exception of the advection into the tropical region, which shows an inconsistent trend between the resolutions. Whereas, the meridional transport of tracers released in the stratosphere was enhanced with higher model resolutions, except in the transport from tropical stratosphere to the Southern Hemisphere, which exhibits an increase trend with increasing model resolution. The idealized tracers exhibit a seasonal cycle, which is modulated by the tracer lifetime. In comparison to the run with prescribed sea surface temperature and sea ice fields, the simulation with prescribed Correspondence to: A. M. Aghedo (adetutu.m.aghedo@jpl.nasa.gov) meteorological fields did not exhibit significant change in the meridional transport, except in the exchange of stratospheric tracers between both hemispheres, where it causes about 100% increase. The import of the surface tracers into the stratosphere is increased by up to a factor of 2.5, and the export from the stratosphere into the troposphere was increased by up to 60% when prescribed meteorological fields is used. The ERA40 simulation also showed larger interannual variability (up to 24% compared to 12% in the standard simulations). Using our surface tracers released in either the northern or Southern Hemisphere, respectively, we calculate inter-hemispheric transport times between 11 and 17 months, consistent with values reported in the literature. While this study cannot be used to relate differences in model results to specific changes in transport processes, it nevertheless provides some insight into the characteristics of tracer transport in the widely used ECHAM5 general circulation model.

show abstract

“…Using a Green's function diagnostic, Bowman and collaborators (Bowman and Carrie 2002;Bowman and Erukhimova 2004;Erukhimova and Bowman 2006) concluded that tropospheric transport can be described qualitatively by the slow mean diabatic circulation and rapid isentropic mixing. In the observations, the mean diabatic circulation exhibits an equator-to-pole cell, with poleward circulations in the stratosphere and in the upper troposphere and an equatorward return flow near the surface (e.g., Tanaka et al 2004).…”

Section: Introductionmentioning

confidence: 99%

Effective Isentropic Diffusivity of Tropospheric Transport

Chen

Plumb

2014

Journal of the Atmospheric Sciences

View full text Add to dashboard Cite

Tropospheric transport can be described qualitatively by the slow mean diabatic circulation and rapid isentropic mixing, yet a quantitative understanding of the transport circulation is complicated, as nearly half of the isentropic surfaces in the troposphere frequently intersect the ground. A theoretical framework for the effective isentropic diffusivity of tropospheric transport is presented. Compared with previous isentropic analysis of effective diffusivity, a new diagnostic is introduced to quantify the eddy diffusivity of the nearsurface isentropic flow. This diagnostic also links the effective eddy diffusivity directly to a diffusive closure of eddy fluxes through a finite-amplitude wave activity equation.The theory is examined in a dry primitive equation model on the sphere. It is found that the upper troposphere is characterized by a diffusivity minimum at the jet's center with enhanced mixing at the jet's flanks and that the lower troposphere is dominated by stronger mixing throughout the baroclinic zone. This structure of isentropic diffusivity is generally consistent with the diffusivity obtained from the geostrophic component of the flow. Furthermore, the isentropic diffusivity agrees broadly with the tracer equivalent length obtained from either a spectral diffusion scheme or a semi-Lagrangian advection scheme, indicating that the effective diffusivity of tropospheric transport is largely dictated by large-scale stirring rather than details of the smallscale diffusion acting on the tracers.

show abstract

Comparison of Global-Scale Lagrangian Transport Properties of the NCEP Reanalysis and CCM3

Cited by 26 publications

References 26 publications

Emission inventories and projections

Emission inventories and projections

Sensitivity of tracer transport to model resolution, prescribed meteorology and tracer lifetime in the general circulation model ECHAM5

Effective Isentropic Diffusivity of Tropospheric Transport

Contact Info

Product

Resources

About