Tropical deep convection and its impact on composition in global and mesoscale models - Part 1: Meteorology and comparison with observations.

Russo, M. R.; Marécal, Virginie; Hoyle, C. R.; Arteta, Joaquim; Chemel, Charles; Chipperfield, Martyn; Dessens, Olivier; Feng, Weiyue; Hosking, J. R. M.; Telford, P.; Wild, Oliver; Yang, Xuan; Pyle, J. A.

doi:10.5194/acpd-10-19469-2010

Cited by 4 publications

(3 citation statements)

References 70 publications

(47 reference statements)

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“…In the first paper (Russo, 2010) (hereafter R 2010), we present a comparison of the models' meteorological parameters with satellite-based measurements. In this second paper we compare the results of model tracer transport.…”

Section: Introductionmentioning

confidence: 99%

Tropical deep convection and its impact on composition in global and mesoscale models – Part 2: Tracer transport

Hoyle¹,

Marécal²,

Russo³

et al. 2010

Preprint

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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), chemistry transport, and climate chemistry 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 hours) within the tropical troposphere. Peak convective outflow altitudes range 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 differ 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 the modelling of the halogen burden of the lowermost stratosphere through species such as bromoform, or for the transport of short lived hydrocarbons into the lowermost stratosphere. The modelled tracer profiles are found to be strongly influenced by the convective transport parameterisations, and boundary layer mixing parameterisations of the models. The location of rapid transport into the upper troposphere is similar among the models, and is mostly concentrated over the western Pacific, the Maritime Continent and the Indian Ocean. In contrast, none of the models indicates significant enhancement in upward transport over western Africa. The mean mixing ratios of an idealised CO like tracer in the upper tropical troposphere are found to be sensitive to the surface CO mixing ratios in the regions with the most active convection, revealing the importance of correctly modelling both the location of convective transport and the geographical pollutant emission patterns

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Section: Introductionmentioning

confidence: 99%

Tropical deep convection and its impact on composition in global and mesoscale models – Part 2: Tracer transport

Hoyle¹,

Marécal²,

Russo³

et al. 2010

Preprint

Self Cite

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show abstract

“…Even though convection is parameterised in the model, recent studies find that this very model setup is suitable for transporting VSLS as shown by comparing the distribution of modelled high cloud to observations (Russo et al, 2010) and vertical transport of idealised short-lived tracers (Hoyle et al, 2010).…”

Section: Discussionmentioning

confidence: 99%

“…Recent studies provide further evidence that this very model setup is suitable for transporting VSLS as shown by comparing the distribution of modelled high cloud to observations (Russo et al, 2010) and vertical convective transport of idealised short-lived tracers (Hoyle et al, 2010). This analysis allows for the comparison between competing hypotheses for troposphere-stratosphere transport (TST), namely of Newell and Gould-Stewart (1981) who proposed a "Stratospheric Fountain" where the Maritime Continent and West Pacific are the main region for TST, and Liu and Zipser (2005) who argue for many "Stratospheric Fountains" (driven by convection over Africa, Maritime Continent and South America).…”

Section: Introductionmentioning

confidence: 90%

Modelling deep convection and its impacts on the tropical tropopause layer

Hosking¹,

Russo²,

Braesicke³

et al. 2010

Preprint

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The UK Met Office's Unified Model is used at a high global resolution (N216, ~0.83° × ~0.56°, ~60 km) to assess the impact of deep tropical convection on the structure of the tropical tropopause layer (TTL). We focus on the potential for rapid transport of short-lived ozone depleting species to the stratosphere by rapid convective uplift. The modelled horizontal structure of organised convection is shown to match closely with signatures found in the OLR satellite data. In the model, deep convective elevators rapidly lift air from 4–5 km up to 12–14 km. The influx of tropospheric air entering the TTL (11–12 km) is similar for all tropical regions with most convection stopping below ~14 km. The tropical tropopause is coldest and driest between November and February, coinciding with the greatest upwelling over the tropical warm pool. As this deep convection is co-located with bromine-rich biogenic coastal emissions, this period and location could potentially be the preferential gateway for stratospheric bromine

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Modelling deep convection and its impacts on the tropical tropopause layer

et al. 2010

Self Cite

View full text Add to dashboard Cite

Abstract. The UK Met Office's Unified Model is used at a climate resolution (N216, ∼0.83 • ×∼0.56 • , ∼60 km) to assess the impact of deep tropical convection on the structure of the tropical tropopause layer (TTL). We focus on the potential for rapid transport of short-lived ozone depleting species to the stratosphere by rapid convective uplift. The modelled horizontal structure of organised convection is shown to match closely with signatures found in the OLR satellite data. In the model, deep convective elevators rapidly lift air from 4-5 km up to 12-14 km. The influx of tropospheric air entering the TTL (11-12 km) is similar for all tropical regions with most convection stopping below ∼14 km. The tropical tropopause is coldest and driest between November and February, coinciding with the greatest upwelling over the tropical warm pool. As this deep convection is co-located with bromine-rich biogenic coastal emissions, this period and location could potentially be the preferential gateway for stratospheric bromine.

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Tropical deep convection and its impact on composition in global and mesoscale models - Part 1: Meteorology and comparison with observations.

Cited by 4 publications

References 70 publications

Tropical deep convection and its impact on composition in global and mesoscale models – Part 2: Tracer transport

Tropical deep convection and its impact on composition in global and mesoscale models – Part 2: Tracer transport

Modelling deep convection and its impacts on the tropical tropopause layer

Modelling deep convection and its impacts on the tropical tropopause layer

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