The sensitivity of a model's stratospheric tape recorder to the choice of advection scheme

Gregory, Alex; West, V.

doi:10.1256/003590002320603430

Cited by 30 publications

(31 citation statements)

References 16 publications

(18 reference statements)

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“…[59] As mentioned in previous work [e.g., Eluszkiewicz et al, 2000;Gregory and West, 2002;Rotman et al, 2001, Figures 3 and 4] the choice of the advection scheme significantly influences the calculated tracer distributions. During the development stage test runs with the semiLagrangian transport scheme (SLT) [Rasch and Williamson, 1990;Rasch et al, 1995] have been performed.…”

Section: Discussionmentioning

confidence: 99%

A new interactive chemistry‐climate model: 1. Present‐day climatology and interannual variability of the middle atmosphere using the model and 9 years of HALOE/UARS data

et al. 2003

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[1] The newly developed middle atmosphere general circulation model with interactive photochemistry, Middle Atmosphere European Centre/Hamburg Model 4 with Chemistry (MA-ECHAM4-CHEM), has been applied for several 20 year ''time slice'' experiments using fixed boundary conditions typical of the early and late 1990s, the 1960s, and the near future, including sensitivity runs to study effects of sea surface temperature and greenhouse gas concentration changes. In part 1 we compare the results for the early and late 1990s with 9 years of data of the Halogen Occultation Experiment (HALOE) on the Upper Atmosphere Research Satellite, some presented for the first time, and other satellite and radiosonde data. We show a statistical analysis as well as snapshots of a set of chemical species for typical situations. The model captures the main features of temperature and ozone distributions including the interannual variability of the Arctic and Antarctic vortices and homogeneous and heterogeneous ozone destruction. A detailed comparison of modeled and observed chlorine and nitrogen species including denitrification and chlorine repartitioning in the polar vortices is presented, showing generally good agreement. This holds also for chemical ozone budgets derived from the model and from satellite data. Computed stratospheric and mesospheric water vapor agrees with the satellite data within about 10%, including dehydration in the Antarctic winter. However, in the tropical lower stratosphere, the concentrations of the source gases are underestimated, presumably because of numerical deficiencies in transport. It is shown that interactive photochemistry is important to get agreement with observed temperatures in the lower stratosphere in highlatitude spring. Our coupled model provides a powerful tool to investigate chemicalradiative-dynamical feedback mechanisms of anthropogenic trace gas emissions and natural variability on climate and stratospheric ozone, at least for quasi-steady-state conditions.INDEX TERMS: 0340 Atmospheric Composition and Structure: Middle atmospherecomposition and chemistry; 0341 Atmospheric Composition and Structure: Middle atmosphere-constituent transport and chemistry (3334); 3337 Meteorology and Atmospheric Dynamics: Numerical modeling and data assimilation; 3319 Meteorology and Atmospheric Dynamics: General circulation; KEYWORDS: chemistryclimate model, stratospheric ozone, UARS satellite data, chlorine partitioning, polar ozone Citation: Steil, B., C. Brühl, E. Manzini, P. J. Crutzen, J. Lelieveld, P. J. Rasch, E. Roeckner, and K. Krüger, A new interactive chemistry-climate model: 1. Present-day climatology and interannual variability of the middle atmosphere using the model and 9 years of HALOE/UARS data,

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Section: Discussionmentioning

confidence: 99%

A new interactive chemistry‐climate model: 1. Present‐day climatology and interannual variability of the middle atmosphere using the model and 9 years of HALOE/UARS data

et al. 2003

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“…Like UMCAM, the horizontal resolution is 2.5 • latitude × 3.75 • longitude but the model has 64 vertical levels between the surface and 0.01 hPa. Advection is calculated with the monotonic Quintic-Mono scheme (Gregory and West, 2002), and convection with the bulk penetrative mass flux scheme (Gregory and Rowntree, 1990). There is no mixing of tracers in the boundary layer.…”

Section: Umslimcat Ccmmentioning

confidence: 99%

Representation of tropical deep convection in atmospheric models – Part 2: Tracer transport

et al. 2011

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Abstract. The tropical transport processes of 14 different models or model versions were compared, within the framework of the SCOUT-O3 (Stratospheric-Climate Links with Emphasis on the Upper Troposphere and Lower Stratosphere) project. The tested models range from the regional to the global scale, and include numerical weather prediction (NWP), chemical transport, and chemistry-climate models. Idealised tracers were used in order to prevent the model's chemistry schemes from influencing the results substantially, so that the effects of modelled transport could be isolated. We find large differences in the vertical transport of very short-lived tracers (with a lifetime of 6 h) within the tropical troposphere. Peak convective outflow altitudes rangeCorrespondence to: C. R. Hoyle (christopher.hoyle@env.ethz.ch) from around 300 hPa to almost 100 hPa among the different models, and the upper tropospheric tracer mixing ratios differ by up to an order of magnitude. The timing of convective events is found to be different between the models, even among those which source their forcing data from the same NWP model (ECMWF). The differences are less pronounced for longer lived tracers, however they could have implications for modelling the halogen burden of the lowermost stratosphere through transport of species such as bromoform, or short-lived hydrocarbons into the lowermost stratosphere. The modelled tracer profiles are strongly influenced by the convective transport parameterisations, and different boundary layer mixing parameterisations also have a large impact on the modelled tracer profiles. Preferential locations for rapid transport from the surface into the upper troposphere are similar in all models, and are mostly concentrated over the western Pacific, the Maritime Continent and the Indian Published by Copernicus Publications on behalf of the European Geosciences Union. Ocean. In contrast, models do not indicate that upward transport is highest over western Africa.

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“…In our version of the UM, the model's default tracer advection scheme has been replaced by the QUINTIC-MONO scheme (Gregory and West 2002). This scheme performs much better in maintaining realistic tracer distributions in the presence of strong gradients.…”

Section: Model and Experiments (A) Met Office Unified Modelmentioning

confidence: 99%

A new coupled chemistry–climate model for the stratosphere: The importance of coupling for future O<SUB>3</SUB>-climate predictions

Tian

Chipperfield

2005

Q. J. R. Meteorol. Soc.

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SUMMARYWe have created a new interactive model for coupled chemistry-climate studies of the stratosphere. The model combines the detailed stratospheric chemistry modules developed and tested in the SLIMCAT/ TOMCAT off-line chemical transport models (CTM) with a version of the Met Office Unified Model (UM). The resulting chemistry-climate model (CCM), called UMCHEM, has a detailed description of stratospheric gasphase and heterogeneous chemistry. The chemical fields of O 3 , N 2 O, CH 4 and H 2 O are used interactively in the radiative heating calculation.We present results from a series of 10-year 'time-slice' experiments for 2000 and 2050 conditions. The UMCHEM model performs well in reproducing basic features of the stratosphere. The distribution of longlived tracers and 'age of air' compare well with observations. For O 3 , the model tends to underestimate the stratospheric column at high latitudes by ∼20 DU. This is due to an underestimate of poleward transport in the mid-low stratosphere. The UMCHEM reproduces well the seasonal cycle in monthly mean column O 3 at midhigh latitudes, though the variability is slightly smaller than observations and smaller than in the SLIMCAT CTM. Other comparisons with the CTM, which has an identical chemistry scheme, show differences resulting from the models' meteorologies. For example, while the CTM reproduces the observed NO y versus N 2 O correlation, the UMCHEM overestimates the slope by about a factor of 2.Including full chemistry in the UM causes important differences in the model's meteorology. As the zonal mean ozone climatology used in the UM is larger than that calculated in UMCHEM, with a maximum difference of 4 ppmv in the upper stratosphere, the UMCHEM temperature is about 4 K lower in the Antarctic lower stratosphere and 1-6 K higher in the upper stratosphere. The age of air is less in the basic UM by about 1-3 months in the lower stratosphere but slightly greater in the upper stratosphere. Coupling of the more realistic stratospheric chemistry water vapour warms the model stratosphere by ∼1-2 K. This water vapour coupling also results in a decrease in ozone with a maximum difference of about 250 ppbv in the tropical and southern highlatitude upper stratosphere, while in the tropical lower stratosphere ozone concentrations are increased by up to 30 ppbv.For 2050 conditions, the model produces a column O 3 5% higher than present-day values in the tropics, about 15% higher in the Arctic winter/spring and up to 90% higher in the much smaller Antarctic O 3 hole. This large O 3 increase more than offsets the effect of cooling in the Antarctic late spring induced by greenhouse gases.

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The sensitivity of a model's stratospheric tape recorder to the choice of advection scheme

Cited by 30 publications

References 16 publications

A new interactive chemistry‐climate model: 1. Present‐day climatology and interannual variability of the middle atmosphere using the model and 9 years of HALOE/UARS data

A new interactive chemistry‐climate model: 1. Present‐day climatology and interannual variability of the middle atmosphere using the model and 9 years of HALOE/UARS data

Representation of tropical deep convection in atmospheric models – Part 2: Tracer transport

A new coupled chemistry–climate model for the stratosphere: The importance of coupling for future O<SUB>3</SUB>-climate predictions

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