scholarly journals Evaluation of the CAMS global atmospheric trace gas reanalysis 2003–2016 using aircraft campaign observations

2020 ◽  
Vol 20 (7) ◽  
pp. 4493-4521 ◽  
Author(s):  
Yuting Wang ◽  
Yong-Feng Ma ◽  
Henk Eskes ◽  
Antje Inness ◽  
Johannes Flemming ◽  
...  

Abstract. The Copernicus Atmosphere Monitoring Service (CAMS) operated by the European Centre for Medium-Range Weather Forecasts (ECMWF) has produced a global reanalysis of aerosol and reactive gases (called CAMSRA) for the period 2003–2016. Space observations of ozone, carbon monoxide, NO2 and aerosol optical depth are assimilated by a 4D-Var method in the 60-layer ECMWF global atmospheric model, which for the reanalysis is operated at a horizontal resolution of about 80 km. As a contribution to the evaluation of the reanalysis, we compare atmospheric concentrations of different reactive species provided by the CAMS reanalysis with independent observational data gathered by airborne instrumentation during the field campaigns INTEX-A, INTEX-B, NEAQS-ITCT, ITOP, AMMA, ARCTAS, VOCALS, YAK-AEROSIB, HIPPO and KORUS-AQ. We show that the reanalysis rather successfully reproduces the observed concentrations of chemical species that are assimilated in the system, including O3 and CO with biases generally less than 20 %, but generally underestimates the concentrations of the primary hydrocarbons and secondary organic species. In some cases, large discrepancies also exist for fast-reacting radicals such as OH and HO2.

2019 ◽  
Author(s):  
Yuting Wang ◽  
Yong-Feng Ma ◽  
Henk Eskes ◽  
Antje Inness ◽  
Johannes Flemming ◽  
...  

Abstract. The Copernicus Atmosphere Monitoring Service (CAMS) operated by the European Centre for Medium Range Weather Forecasts (ECMWF) has produced a global reanalysis of aerosol and reactive gases (called CAMSRA) for the period 2003–2016. Space observations of ozone, carbon monoxide, NO2 and aerosol optical depth are assimilated by a 4-D Var method in the 60-layer ECMWF global atmospheric model, which for the reanalysis is operated at a horizontal resolution of about 80 km. As a contribution to the evaluation of the reanalysis, we compare atmospheric concentrations of different reactive species provided by the CAMS reanalysis with independent observational data gathered by airborne instrumentation during the field campaigns INTEX-A, INTEX-B, NEAQS-ITCT, ITOP, AMMA, ARCTAS, VOCALS, YAK-AEROSIB, HIPPO and KORUS-AQ. We show that the reanalysis reproduces rather successfully the observed concentrations of chemical species that are assimilated in the system including O3 and CO with the biases generally less than 20 %, but generally underestimate the concentrations of the primary hydrocarbons and secondary organic species. In some cases, large discrepancies also exist for fast-reacting radicals such as OH and HO2.


2016 ◽  
Vol 31 (5) ◽  
pp. 1547-1572 ◽  
Author(s):  
Silvio N. Figueroa ◽  
José P. Bonatti ◽  
Paulo Y. Kubota ◽  
Georg A. Grell ◽  
Hugh Morrison ◽  
...  

Abstract This article describes the main features of the Brazilian Global Atmospheric Model (BAM), analyses of its performance for tropical rainfall forecasting, and its sensitivity to convective scheme and horizontal resolution. BAM is the new global atmospheric model of the Center for Weather Forecasting and Climate Research [Centro de Previsão de Tempo e Estudos Climáticos (CPTEC)], which includes a new dynamical core and state-of-the-art parameterization schemes. BAM’s dynamical core incorporates a monotonic two-time-level semi-Lagrangian scheme, which is carried out completely on the model grid for the tridimensional transport of moisture, microphysical prognostic variables, and tracers. The performance of the quantitative precipitation forecasts (QPFs) from two convective schemes, the Grell–Dévényi (GD) scheme and its modified version (GDM), and two different horizontal resolutions are evaluated against the daily TRMM Multisatellite Precipitation Analysis over different tropical regions. Three main results are 1) the QPF skill was improved substantially with GDM in comparison to GD; 2) the increase in the horizontal resolution without any ad hoc tuning improves the variance of precipitation over continents with complex orography, such as Africa and South America, whereas over oceans there are no significant differences; and 3) the systematic errors (dry or wet biases) remain virtually unchanged for 5-day forecasts. Despite improvements in the tropical precipitation forecasts, especially over southeastern Brazil, dry biases over the Amazon and La Plata remain in BAM. Improving the precipitation forecasts over these regions remains a challenge for the future development of the model to be used not only for numerical weather prediction over South America but also for global climate simulations.


2008 ◽  
Vol 65 (1) ◽  
pp. 263-275 ◽  
Author(s):  
Richard Kleeman

Abstract The nature of statistical predictability is analyzed in a T42 global atmospheric model that is able to adequately capture the main features of the midlatitude atmosphere. Key novel features of the present study include very large prediction ensembles and information theoretic techniques. It is found globally that predictability declines in a quasi-linear fashion with time for short-term predictions (3–25 days), while for long ranges (30–45 days) there is an exponential tail. In general, beyond 45 days the prediction and climatological ensembles have essentially converged, which means that beyond that point, atmospheric initial conditions are irrelevant to atmospheric statistical prediction. Regional predictions show considerable variation in behavior. Both of the (northern) winter storm-track regions show a close-to-quasi-linear decline in predictability toward a cutoff at around 40 days. The (southern) summer storm track shows a much more exponential and considerably slower decline with a small amount of predictability still in evidence even at 90 days. Because the winter storm tracks dominate global variance the behavior of their predictability tends to dominate the global measure, except at longer lags. Variability in predictability with respect to initial conditions is also examined, and it is found that this is related more strongly to ensemble signal rather than ensemble spread. This result may serve to explain why the relation between weather forecast skill and ensemble spread is often observed to be significantly less than perfect. Results herein suggest that the ensemble signal as well as spread variations may be a major contributor to skill variations. Finally, it is found that the sensitivity of the calculated global predictability to changes in model horizontal resolution is not large; results from a T85 resolution model are not qualitatively all that different from the T42 case.


2017 ◽  
Vol 14 ◽  
pp. 247-251 ◽  
Author(s):  
Dragan Latinović ◽  
Sin Chan Chou ◽  
Miodrag Rančić

Abstract. Global Eta Framework (GEF) is a global atmospheric model developed in general curvilinear coordinates and capable of running on arbitrary rectangular quasi-uniform spherical grids, using stepwise (Eta) representation of the terrain. In this study, the model is run on a cubed-sphere grid topology, in a version with uniform Jacobians (UJ), which provides equal-area grid cells, and a smooth transition of coordinate lines across the edges of the cubed-sphere. Within a project at the Brazilian Center for Weather Forecasts and Climate Studies (CPTEC), a nonhydrostatic version of this model is under development and will be applied for seasonal prediction studies. This note describes preliminary tests with the GEF on the UJ cubed-sphere in which model performance is evaluated in seasonal simulations at a horizontal resolution of approximately 25 km, running in the hydrostatic mode. Comparison of these simulations with the ERA-Interim reanalyses shows that the 850 hPa temperature is underestimated, while precipitation pattern is mostly underestimated in tropical continental regions and overestimated in tropical oceanic regions. Nevertheless, the model is still able to well capture the main seasonal climate characteristics. These results will be used as a control run in further tests with the nonhydrostatic version of the model.


1991 ◽  
Vol 02 (01) ◽  
pp. 158-186 ◽  
Author(s):  
A.J. SIMMONS ◽  
D. DENT

A general introduction to numerical weather prediction is given. The development of the operational forecasting system of the European Centre for Medium-Range Weather Forecasts is summarized, and some results are presented illustrating sensitivity to the horizontal resolution of the atmospheric model, the factor which is most significant in determining computational needs. The spectral method used for the horizontal discretization is described, and computational aspects of its implementation on CRAY-1 and CRAY X-MP machines are discussed. The organization of the multi-tasking employed in the model is presented, and performance figures are given. There is a brief concluding discussion of some likely future developments in medium-range weather prediction.


2019 ◽  
Vol 19 (6) ◽  
pp. 3515-3556 ◽  
Author(s):  
Antje Inness ◽  
Melanie Ades ◽  
Anna Agustí-Panareda ◽  
Jérôme Barré ◽  
Anna Benedictow ◽  
...  

Abstract. The Copernicus Atmosphere Monitoring Service (CAMS) reanalysis is the latest global reanalysis dataset of atmospheric composition produced by the European Centre for Medium-Range Weather Forecasts (ECMWF), consisting of three-dimensional time-consistent atmospheric composition fields, including aerosols and chemical species. The dataset currently covers the period 2003–2016 and will be extended in the future by adding 1 year each year. A reanalysis for greenhouse gases is being produced separately. The CAMS reanalysis builds on the experience gained during the production of the earlier Monitoring Atmospheric Composition and Climate (MACC) reanalysis and CAMS interim reanalysis. Satellite retrievals of total column CO; tropospheric column NO2; aerosol optical depth (AOD); and total column, partial column and profile ozone retrievals were assimilated for the CAMS reanalysis with ECMWF's Integrated Forecasting System. The new reanalysis has an increased horizontal resolution of about 80 km and provides more chemical species at a better temporal resolution (3-hourly analysis fields, 3-hourly forecast fields and hourly surface forecast fields) than the previously produced CAMS interim reanalysis. The CAMS reanalysis has smaller biases compared with most of the independent ozone, carbon monoxide, nitrogen dioxide and aerosol optical depth observations used for validation in this paper than the previous two reanalyses and is much improved and more consistent in time, especially compared to the MACC reanalysis. The CAMS reanalysis is a dataset that can be used to compute climatologies, study trends, evaluate models, benchmark other reanalyses or serve as boundary conditions for regional models for past periods.


2015 ◽  
Vol 8 (11) ◽  
pp. 3523-3543 ◽  
Author(s):  
H. Eskes ◽  
V. Huijnen ◽  
A. Arola ◽  
A. Benedictow ◽  
A.-M. Blechschmidt ◽  
...  

Abstract. The European MACC (Monitoring Atmospheric Composition and Climate) project is preparing the operational Copernicus Atmosphere Monitoring Service (CAMS), one of the services of the European Copernicus Programme on Earth observation and environmental services. MACC uses data assimilation to combine in situ and remote sensing observations with global and regional models of atmospheric reactive gases, aerosols, and greenhouse gases, and is based on the Integrated Forecasting System of the European Centre for Medium-Range Weather Forecasts (ECMWF). The global component of the MACC service has a dedicated validation activity to document the quality of the atmospheric composition products. In this paper we discuss the approach to validation that has been developed over the past 3 years. Topics discussed are the validation requirements, the operational aspects, the measurement data sets used, the structure of the validation reports, the models and assimilation systems validated, the procedure to introduce new upgrades, and the scoring methods. One specific target of the MACC system concerns forecasting special events with high-pollution concentrations. Such events receive extra attention in the validation process. Finally, a summary is provided of the results from the validation of the latest set of daily global analysis and forecast products from the MACC system reported in November 2014.


2020 ◽  
Author(s):  
Jerome Barre ◽  
Ilse Aben ◽  
Melanie Ades ◽  
Anna Agusti-Panareda ◽  
Gianpaolo Balsamo ◽  
...  

<p>The European Union’s Copernicus Atmosphere Monitoring Service (CAMS) operationally provides daily forecasts of global atmospheric composition. It uses the ECMWF Integrated Forecasting System (IFS), which includes meteorological and atmospheric composition variables, such as reactive gases, greenhouse gases and aerosols, for its global forecasts and reanalyses. The current green-house gases operational suite monitors CH4 and CO2 and assimilates TANSO and IASI retrievals for both species. The TROPOspheric Monitoring Instrument (TROPOMI) on board the Sentinel-5 Precursor (S5P) satellite launched in October 2017 yields a wealth of atmospheric composition data, including CH<sub>4</sub> retrievals at unprecedented high horizontal resolution (7km) and up to daily revisit time. We used the IFS to perform monitoring experiments at different horizontal resolutions (25 km and 9 km). We also performed first data assimilation experiments at 25 km horizontal resolution.</p><p>This first set of monitoring experiments shows the potential of the TROPOMI CH<sub>4</sub> retrievals to correct known biases that exist in the current CAMS analyses and forecasts. Assimilation experiments of TROPOMI CH<sub>4</sub> shows that adding the instrument in the operational chain would significantly improve the analysis and forecasts. Detection of CH<sub>4</sub> sources seen by TROPOMI compared to CAMS also shows the potential of the instrument to inform on and infer anthropogenic and natural sources. For example, discrepancies between TROPOMI retrievals and CAMS fields in the CH<sub>4</sub> levels associated with oil and gas extraction activities show very promising perspectives for monitoring and analysis of CH<sub>4</sub> concentration and emissions. We will finally discuss the challenges and progress made towards performing inversions using the IFS operational system.  </p>


Atmosphere ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 192
Author(s):  
Rita Cesari ◽  
Tony Christian Landi ◽  
Massimo D’Isidoro ◽  
Mihaela Mircea ◽  
Felicita Russo ◽  
...  

This work presents the on-line coupled meteorology–chemistry transport model BOLCHEM, based on the hydrostatic meteorological BOLAM model, the gas chemistry module SAPRC90, and the aerosol dynamic module AERO3. It includes parameterizations to describe natural source emissions, dry and wet removal processes, as well as the transport and dispersion of air pollutants. The equations for different processes are solved on the same grid during the same integration step, by means of a time-split scheme. This paper describes the model and its performance at horizontal resolution of 0.2∘× 0.2∘ over Europe and 0.1∘× 0.1∘ in a nested configuration over Italy, for one year run (December 2009–November 2010). The model has been evaluated against the AIRBASE data of the European Environmental Agency. The basic statistics for higher resolution simulations of O3, NO2 and particulate matter concentrations (PM2.5 and PM10) have been compared with those from Copernicus Atmosphere Monitoring Service (CAMS) ensemble median. In summer, for O3 we found a correlation coefficient R of 0.72 and mean bias of 2.15 over European domain and a correlation coefficient R of 0.67 and mean bias of 2.36 over Italian domain. PM10 and PM2.5 are better reproduced in the winter, the latter with a correlation coefficient R of 0.66 and the mean bias MB of 0.35 over Italian domain.


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