| 1. |
- Koster, R., et al.
(författare)
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Contribution of land surface initialization to subseasonal forecast skill: First results from a multi-model experiment
- 2010
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Ingår i: Geophysical Research Letters. - 0094-8276. ; 37
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Tidskriftsartikel (refereegranskat)abstract
- The second phase of the Global Land-Atmosphere Coupling Experiment (GLACE-2) is aimed at quantifying, with a suite of long-range forecast systems, the degree to which realistic land surface initialization contributes to the skill of subseasonal precipitation and air temperature forecasts. Results, which focus here on North America, show significant contributions to temperature prediction skill out to two months across large portions of the continent. For precipitation forecasts, contributions to skill are much weaker but are still significant out to 45 days in some locations. Skill levels increase markedly when calculations are conditioned on the magnitude of the initial soil moisture anomaly.
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| 2. |
- Janssens-Maenhout, G., et al.
(författare)
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Toward an operational anthropogenic CO2 emissions monitoring and verification support capacity
- 2020
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Ingår i: Bulletin of the American Meteorological Society. - 0003-0007. ; 101:8, s. 1439-1451
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Tidskriftsartikel (refereegranskat)abstract
- Under the Paris Agreement (PA), progress of emission reduction efforts is tracked on the basis of regular updates to national greenhouse gas (GHG) inventories, referred to as bottom-up estimates. However, only top-down atmospheric measurements can provide observation-based evidence of emission trends. Today, there is no internationally agreed, operational capacity to monitor anthropogenic GHG emission trends using atmospheric measurements to complement national bottom-up inventories. The European Commission (EC), the European Space Agency, the European Centre for Medium-Range Weather Forecasts, the European Organisation for the Exploitation of Meteorological Satellites, and international experts are joining forces to develop such an operational capacity for monitoring anthropogenic CO2 emissions as a new CO2 service under the EC's Copernicus program. Design studies have been used to translate identified needs into defined requirements and functionalities of this anthropogenic CO2 emissions Monitoring and Verification Support (CO2MVS) capacity. It adopts a holistic view and includes components such as atmospheric spaceborne and in situ measurements, bottom-up CO2 emission maps, improved modeling of the carbon cycle, an operational data-assimilation system integrating top-down and bottom-up information, and a policy-relevant decision support tool. The CO2MVS capacity with operational capabilities by 2026 is expected to visualize regular updates of global CO2 emissions, likely at 0.05° x 0.05°. This will complement the PA's enhanced transparency framework, providing actionable information on anthropogenic CO2 emissions that are the main driver of climate change. This information will be available to all stakeholders, including governments and citizens, allowing them to reflect on trends and effectiveness of reduction measures. The new EC gave the green light to pass the CO2MVS from exploratory to implementing phase.
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| 3. |
- Koster, R. D., et al.
(författare)
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The Second Phase of the Global Land–Atmosphere Coupling Experiment: Soil Moisture Contributions to Subseasonal Forecast Skill
- 2011
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Ingår i: Journal of Hydrometeorology. - : American Meteorological Society. - 1525-755X .- 1525-7541. ; 12:5, s. 805-822
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Tidskriftsartikel (refereegranskat)abstract
- The second phase of the Global Land–Atmosphere Coupling Experiment (GLACE-2) is a multi-institutional numerical modeling experiment focused on quantifying, for boreal summer, the subseasonal (out to two months) forecast skill for precipitation and air temperature that can be derived from the realistic initialization of land surface states, notably soil moisture. An overview of the experiment and model behavior at the global scale is described here, along with a determination and characterization of multimodel “consensus” skill. The models show modest but significant skill in predicting air temperatures, especially where the rain gauge network is dense. Given that precipitation is the chief driver of soil moisture, and thereby assuming that rain gauge density is a reasonable proxy for the adequacy of the observational network contributing to soil moisture initialization, this result indeed highlights the potential contribution of enhanced observations to prediction. Land-derived precipitation forecast skill is much weaker than that for air temperature. The skill for predicting air temperature, and to some extent precipitation, increases with the magnitude of the initial soil moisture anomaly. GLACE-2 results are examined further to provide insight into the asymmetric impacts of wet and dry soil moisture initialization on skill.
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| 4. |
- Alessandri, Andrea, et al.
(författare)
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Multi-scale enhancement of climate prediction over land by increasing the model sensitivity to vegetation variability in EC-Earth
- 2017
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Ingår i: Climate Dynamics. - : Springer Science and Business Media LLC. - 1432-0894 .- 0930-7575. ; 49:4, s. 1215-1237
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Tidskriftsartikel (refereegranskat)abstract
- The EC-Earth earth system model has been recently developed to include the dynamics of vegetation. In its original formulation, vegetation variability is simply operated by the Leaf Area Index (LAI), which affects climate basically by changing the vegetation physiological resistance to evapotranspiration. This coupling has been found to have only a weak effect on the surface climate modeled by EC-Earth. In reality, the effective sub-grid vegetation fractional coverage will vary seasonally and at interannual time-scales in response to leaf-canopy growth, phenology and senescence. Therefore it affects biophysical parameters such as the albedo, surface roughness and soil field capacity. To adequately represent this effect in EC-Earth, we included an exponential dependence of the vegetation cover on the LAI. By comparing two sets of simulations performed with and without the new variable fractional-coverage parameterization, spanning from centennial (twentieth century) simulations and retrospective predictions to the decadal (5-years), seasonal and weather time-scales, we show for the first time a significant multi-scale enhancement of vegetation impacts in climate simulation and prediction over land. Particularly large effects at multiple time scales are shown over boreal winter middle-to-high latitudes over Canada, West US, Eastern Europe, Russia and eastern Siberia due to the implemented time-varying shadowing effect by tree-vegetation on snow surfaces. Over Northern Hemisphere boreal forest regions the improved representation of vegetation cover tends to correct the winter warm biases, improves the climate change sensitivity, the decadal potential predictability as well as the skill of forecasts at seasonal and weather time-scales. Significant improvements of the prediction of 2 m temperature and rainfall are also shown over transitional land surface hot spots. Both the potential predictability at decadal time-scale and seasonal-forecasts skill are enhanced over Sahel, North American Great Plains, Nordeste Brazil and South East Asia, mainly related to improved performance in the surface evapotranspiration.
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| 5. |
- Grant, Luke, et al.
(författare)
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Attribution of global lake systems change to anthropogenic forcing
- 2021
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Ingår i: Nature Geoscience. - : Springer Nature. - 1752-0894 .- 1752-0908. ; 14:11, s. 849-854
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Tidskriftsartikel (refereegranskat)abstract
- Lake ecosystems are jeopardized by the impacts of climate change on ice seasonality and water temperatures. Yet historical simulations have not been used to formally attribute changes in lake ice and temperature to anthropogenic drivers. In addition, future projections of these properties are limited to individual lakes or global simulations from single lake models. Here we uncover the human imprint on lakes worldwide using hindcasts and projections from five lake models. Reanalysed trends in lake temperature and ice cover in recent decades are extremely unlikely to be explained by pre-industrial climate variability alone. Ice-cover trends in reanalysis are consistent with lake model simulations under historical conditions, providing attribution of lake changes to anthropogenic climate change. Moreover, lake temperature, ice thickness and duration scale robustly with global mean air temperature across future climate scenarios (+0.9 °C °Cair–1, –0.033 m °Cair–1 and –9.7 d °Cair–1, respectively). These impacts would profoundly alter the functioning of lake ecosystems and the services they provide.
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| 6. |
- Zhou, Ming, et al.
(författare)
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Oligoamine ionic liquids supported on mesoporous microspheres for CO2 separation with good sorption kinetics and low cost
- 2020
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Ingår i: Journal of CO2 Utilization. - : Elsevier. - 2212-9820 .- 2212-9839. ; 39
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Tidskriftsartikel (refereegranskat)abstract
- Ionic liquids display good CO2 absorption capacity but poor absorption kinetics and high costs. In the present work, we show that these problems can be solved by impregnating the new low cost ionic liquid pentaethylenehexammonium chloride [PEHA][Cl] and the corresponding amine precursor on a low cost mesoporous microsphere support. Nitrogen adsorption/ desorption, high-resolution SEM and thermogravimetric analysis were employed to analyze the structural and thermal properties of the prepared sorbents. The CO2 adsorption and desorption performance was studied by column experiments and mathematical models were fitted to the data. The results showed that sorbents displayed excellent sorption kinetics and capacity, comparable to the best reports in the literature. In addition, the sorbents could be regenerated and displayed high thermal stability. Finally, the costs of the sorbents developed in the present work is much lower than previously reported sorbents. Therefore this novel supported IL system could be promising for industrial CO2 removal and recovery applications.
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