On the use of mass-conserving wind fields in chemistry-transport models

Bregman, B.; Segers, Arjo; Krol, Maarten; Meijer, E.; Velthoven, P. van

doi:10.5194/acp-3-447-2003

Cited by 51 publications

(35 citation statements)

References 24 publications

(37 reference statements)

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“…The seasonality of CO biomass emissions is based on the Hao and Liu [1994] estimates. Meteorological ECMWF analysis input fields used in TM4 are pre-processed as described by Bregman et al [2003].…”

Section: Model Descriptionmentioning

confidence: 99%

Quantitative analysis of SCIAMACHY carbon monoxide total column measurements

Laat

Gloudemans

Schrijver

et al. 2006

Geophysical Research Letters

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[1] This paper presents a first quantitative and systematic analysis of one year of SCIAMACHY Carbon Monoxide (CO) total column retrievals from the IMLM algorithm (v6.3) using a chemistry-transport model simulation. The global distribution of modeled and measured CO show similar spatial patterns: a north-south gradient, low CO over mountains, and high CO over emission regions. CO column errors due to instrument noise are closely related to surface albedo and are less than 6% for monthly means at high surface albedo locations, improving to $1% for ideal circumstances: cloud-free pixels, high surface albedo, and spatial averaging (3°Â 2°). Quantitative comparison shows that measured and modeled seasonality agree very well at several locations with different types of seasonal cycles. Differences between SCIAMACHY CO and model results are less than 13% except for regions with large instrument-noise errors. Differences larger than the 2s instrument-noise error (95% confidence interval) occur in some regions with small noise errors, for example southern Africa. In this case the SCIAMACHY CO variations are different from the model biomass-burning emission seasonal cycle and more in agreement with observed fire count seasonality. The comparison with model results indicates that despite unforeseen time-dependent instrument-calibration complications, SCIAMACHY CO total column retrievals are of sufficient quality to provide useful new information on the global distribution and variation of CO. Citation: de Laat, A. T.

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Section: Model Descriptionmentioning

confidence: 99%

Quantitative analysis of SCIAMACHY carbon monoxide total column measurements

Laat

Gloudemans

Schrijver

et al. 2006

Geophysical Research Letters

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“…Here the vertical mass fluxes are calculated directly from the spectral fields, and the local mass balance over the exchange interval is closed by slightly adjusting the horizontal mass fluxes. This method has been shown to lead to superior chemistry simulations compared to methods that make use of interpolated wind fields (Bregman et al, 2003).…”

Section: Data Exchange and Transformationsmentioning

confidence: 99%

Simulation of tropospheric chemistry and aerosols with the climate model EC-Earth

et al. 2014

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Abstract. We have integrated the atmospheric chemistry and transport model TM5 into the global climate model EC-Earth version 2.4. We present an overview of the TM5 model and the two-way data exchange between TM5 and the IFS model from the European Centre for Medium-Range Weather Forecasts (ECMWF), the atmospheric general circulation model of EC-Earth. In this paper we evaluate the simulation of tropospheric chemistry and aerosols in a oneway coupled configuration. We have carried out a decadal simulation for present-day conditions and calculated chemical budgets and climatologies of tracer concentrations and aerosol optical depth. For comparison we have also performed offline simulations driven by meteorological fields from ECMWF's ERA-Interim reanalysis and output from the EC-Earth model itself. Compared to the offline simulations, the online-coupled system produces more efficient vertical mixing in the troposphere, which reflects an improvement of the treatment of cumulus convection. The chemistry in the EC-Earth simulations is affected by the fact that the current version of EC-Earth produces a cold bias with too dry air in large parts of the troposphere. Compared to the ERA-Interim driven simulation, the oxidizing capacity in EC-Earth is lower in the tropics and higher in the extratropics. The atmospheric lifetime of methane in EC-Earth is 9.4 years, which is 7 % longer than the lifetime obtained with ERA-Interim but remains well within the range reported in the literature. We further evaluate the model by comparing the simulated climatologies of surface radon-222 and carbon monoxide, tropospheric and surface ozone, and aerosol optical depth against observational data. The work presented in this study is the first step in the development of EC-Earth into an Earth system model with fully interactive atmospheric chemistry and aerosols.

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“…Furthermore, temporal snapshots of reanalysis data are not physically consistent with each other (Stohl et al, 2004). Therefore, in offline transport calculation, reanalysis wind data should be modified in advance to restore the dynamical consistency with pressure tendencies; otherwise the tracer mass cannot be conserved (Heimann and Keeling, 1989;Heimann, 1995;Bregman et al, 2003). …”

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confidence: 99%

A 4D-Var inversion system based on the icosahedral grid model (NICAM-TM 4D-Var v1.0) – Part 1: Offline forward and adjoint transport models

et al. 2017

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Abstract. A four-dimensional variational (4D-Var) method is a popular algorithm for inverting atmospheric greenhouse gas (GHG) measurements. In order to meet the computationally intense 4D-Var iterative calculation, offline forward and adjoint transport models are developed based on the Nonhydrostatic ICosahedral Atmospheric Model (NICAM). By introducing flexibility into the temporal resolution of the input meteorological data, the forward model developed in this study is not only computationally efficient, it is also found to nearly match the transport performance of the online model. In a transport simulation of atmospheric carbon dioxide (CO 2 ), the data-thinning error (error resulting from reduction in the time resolution of the meteorological data used to drive the offline transport model) is minimized by employing high temporal resolution data of the vertical diffusion coefficient; with a low 6-hourly temporal resolution, significant concentration biases near the surface are introduced. The new adjoint model can be run in discrete or continuous adjoint mode for the advection process. The discrete adjoint is characterized by perfect adjoint relationship with the forward model that switches off the flux limiter, while the continuous adjoint is characterized by an imperfect but reasonable adjoint relationship with its corresponding forward model. In the latter case, both the forward and adjoint models use the flux limiter to ensure the monotonicity of tracer concentrations and sensitivities. Trajectory analysis for high CO 2 concentration events are performed to test adjoint sensitivities. We also demonstrate the potential usefulness of our adjoint model for diagnosing tracer transport. Both the offline forward and adjoint models have computational efficiency about 10 times higher than the online model. A description of our new 4D-Var system that includes an optimization method, along with its application in an atmospheric CO 2 inversion and the effects of using either the discrete or continuous adjoint method, is presented in an accompanying paper (Niwa et al., 2016).

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On the use of mass-conserving wind fields in chemistry-transport models

Cited by 51 publications

References 24 publications

Quantitative analysis of SCIAMACHY carbon monoxide total column measurements

Quantitative analysis of SCIAMACHY carbon monoxide total column measurements

Simulation of tropospheric chemistry and aerosols with the climate model EC-Earth

A 4D-Var inversion system based on the icosahedral grid model (NICAM-TM 4D-Var v1.0) – Part 1: Offline forward and adjoint transport models

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