Ensemble analysis of frost damage on vegetation caused by spring backlashes in a warmer Europe

Abstract. Tree dehardening and budburst will occur earlier in a warmer climate, and this could lead to an increased risk of frost damage caused by temperature backlashes. By using a spring backlash index and a cold hardiness model, we assessed different aspects of risk for frost damage in Norway spruce forests during the present climate and for one future emission scenario. Uncertainties associated with climate modelling were quantified by using temperature data from three climate data sets: (1) E-Obs gridded observed climate data, (2) an ensemble of data from eight regional climate models (RCM) forced by ERA-40 reanalysis data, (3) an ensemble of regional climate scenarios produced by the regional climate model RCA3 driven at the boundary conditions by seven global climate models (GCM), all representing the SRES A1B emission scenario. The frost risk was analysed for three periods, 1961–1990, 2011–2040 and 2070–2097. The RCA3_GCM ensemble indicated that the risk for spring frost damage may increase in the boreo-nemoral forest zone of southern Scandinavia and the Baltic states/Belarus. This is due to an increased frequency of backlashes, lower freezing temperatures after the onset of the vegetation period and the last spring frost occurring when the trees are closer to budburst. The changes could be transient due to the fine balance between an increased risk of frost damage caused by dehardening during a period when freezing temperatures are common and a decreased risk caused by warmer temperatures. In the nemoral zone, the zone with highest risk for spring backlashes during the reference period (1961–1990), the spring frost severity may increase due to frost events occurring when the trees are closer to budburst. However, the risk in terms of frequency of backlashes and freezing temperature were projected to become lower already in the beginning of this century.

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COSMO-CLM Regional Climate Simulations in the CORDEX framework: a review

10.5194/gmd-2020-443 ◽

2021 ◽

Author(s):

Silje Lund Sørland ◽

Roman Brogli ◽

Praveen Kumar Pothapakula ◽

Emmanuele Russo ◽

Jonas Van de Walle ◽

...

Keyword(s):

Climate Models ◽

Regional Climate ◽

Parameter Tuning ◽

Horizontal Resolution ◽

Global Climate Models ◽

Limited Area ◽

Climate Projections ◽

Climate Modelling ◽

Near Surface ◽

Climate Simulations

Abstract. In the last decade, the Climate Limited-area Modeling (CLM) Community has contributed to the Coordinated Re- gional Climate Downscaling Experiment (CORDEX) with an extensive set of regional climate simulations. Using several versions of the COSMO-CLM community model, ERA-Interim reanalysis and eight Global Climate Models from phase 5 of the Coupled Model Intercomparison Project (CMIP5) were dynamically downscaled with horizontal grid spacings of 0.44° (∼50 km), 0.22° (∼25 km) and 0.11° (∼12 km) over the CORDEX domains Europe, South Asia, East Asia, Australasia and Africa. This major effort resulted in 80 regional climate simulations publicly available through the Earth System Grid Fed- eration (ESGF) web portals for use in impact studies and climate scenario assessments. Here we review the production of these simulations and assess their results in terms of mean near-surface temperature and precipitation to aid the future design of the COSMO-CLM model simulations. It is found that a domain-specific parameter tuning is beneficial, while increasing horizontal model resolution (from 50 to 25 or 12 km grid spacing) alone does not always improve the performance of the simulation. Moreover, the COSMO-CLM performance depends on the driving data. This is generally more important than the dependence on horizontal resolution, model version and configuration. Our results emphasize the importance of performing regional climate projections in a coordinated way, where guidance from both the global (GCM) and regional (RCM) climate modelling communities is needed to increase the reliability of the GCM-RCM modelling chain.

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Design of a regional climate modelling projection ensemble experiment – NARCliM

Geoscientific Model Development ◽

10.5194/gmd-7-621-2014 ◽

2014 ◽

Vol 7 (2) ◽

pp. 621-629 ◽

Cited By ~ 112

Author(s):

J. P. Evans ◽

F. Ji ◽

C. Lee ◽

P. Smith ◽

D. Argüeso ◽

...

Keyword(s):

Climate Change ◽

Climate Models ◽

Selection Process ◽

Regional Climate ◽

Global Climate Models ◽

Regional Climate Modelling ◽

Future Research ◽

Climate Projections ◽

Climate Modelling ◽

Future Change

Abstract. Including the impacts of climate change in decision making and planning processes is a challenge facing many regional governments including the New South Wales (NSW) and Australian Capital Territory (ACT) governments in Australia. NARCliM (NSW/ACT Regional Climate Modelling project) is a regional climate modelling project that aims to provide a comprehensive and consistent set of climate projections that can be used by all relevant government departments when considering climate change. To maximise end user engagement and ensure outputs are relevant to the planning process, a series of stakeholder workshops were run to define key aspects of the model experiment including spatial resolution, time slices, and output variables. As with all such experiments, practical considerations limit the number of ensemble members that can be simulated such that choices must be made concerning which global climate models (GCMs) to downscale from, and which regional climate models (RCMs) to downscale with. Here a methodology for making these choices is proposed that aims to sample the uncertainty in both GCM and RCM ensembles, as well as spanning the range of future climate projections present in the GCM ensemble. The RCM selection process uses performance evaluation metrics to eliminate poor performing models from consideration, followed by explicit consideration of model independence in order to retain as much information as possible in a small model subset. In addition to these two steps the GCM selection process also considers the future change in temperature and precipitation projected by each GCM. The final GCM selection is based on a subjective consideration of the GCM independence and future change. The created ensemble provides a more robust view of future regional climate changes. Future research is required to determine objective criteria that could replace the subjective aspects of the selection process.

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A Comprehensive Intermediate-Term Drought Evaluation System and Evaluation of Climate Data Products over the Conterminous United States

Journal of Hydrometeorology ◽

10.1175/jhm-d-20-0314.1 ◽

2021 ◽

Author(s):

Zeyu Xue ◽

Paul Ullrich

Keyword(s):

Evaluation System ◽

Climate Models ◽

Global Climate ◽

Statistical Significance ◽

Regional Climate ◽

Regional Climate Models ◽

Global Climate Models ◽

Statistical Hypothesis ◽

Climate Data ◽

Statistical Hypothesis Testing

AbstractClimate models are frequently-used tools for adaptation planning in light of future uncertainty. However, not all climate models are equally trustworthy, and so model biases must be assessed to select models suitable for producing credible projections. Drought is a well-known and high-impact form of extreme weather, and knowledge of its frequency, intensity, and duration key for regional water management plans. Droughts are also difficult to assess in climate datasets, due to the long duration per event, relative to the length of a typical simulation. Therefore, there is a growing need for a standardized suite of metrics addressing how well models capture this phenomenon. In this study, we present a widely applicable set of metrics for evaluating agreement between climate datasets and observations in the context of drought. Two notable advances are made in our evaluation system: First, statistical hypothesis testing is employed for normalization of individual scores against the threshold for statistical significance. And second, within each evaluation region and dataset, principal feature analysis is used to select the most descriptive metrics among 11 metrics that capture essential features of drought. Our metrics package is applied to three characteristically distinct regions in the conterminous US and across several commonly employed climate datasets (CMIP5/6, LOCA and CORDEX). As a result, insights emerge into the underlying drivers of model bias in global climate models, regional climate models, and statistically downscaled models.

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A regional climate modelling projection ensemble experiment – NARCliM

Geoscientific Model Development Discussions ◽

10.5194/gmdd-6-5117-2013 ◽

2013 ◽

Vol 6 (3) ◽

pp. 5117-5139 ◽

Cited By ~ 3

Author(s):

J. P. Evans ◽

F. Ji ◽

C. Lee ◽

P. Smith ◽

D. Argüeso ◽

...

Keyword(s):

Climate Change ◽

Climate Models ◽

Planning Process ◽

Global Climate ◽

Regional Climate ◽

Global Climate Models ◽

Regional Climate Modelling ◽

Climate Projections ◽

Climate Modelling ◽

User Engagement

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Analysis of the observed and modelled budburst dates of grapevine in Croatia

10.5194/ems2021-20 ◽

2021 ◽

Author(s):

Branimir Omazić ◽

Maja Telišman Prtenjak ◽

Ivan Prša ◽

Marko Karoglan

Keyword(s):

Climate Change ◽

Climate Models ◽

Global Climate ◽

Regional Climate ◽

Regional Climate Models ◽

Climatic Conditions ◽

Global Climate Models ◽

Statistical Characteristics ◽

Base Temperature ◽

Spring Frost

Since changes in temperatures and precipitation significantly affect the biosphere, viticulture as an important economic branch in the moderate latitudes (e.g., mainly between 35&#176;N and 55&#176;N) is strongly influenced by climate change. The most commonly analysed/modelled phenological phases of grapevines are budburst (beginning of grapevine seasonal growth), flowering (crucial for the reproductive cycle) and veraison (initiation of the ripening). Resent studies indicate that budburst is greatly regulated by temperature. Due to climate change and temperature increase, budburst dates show trends in earlier occurrences at several available stations throughout Croatia which increases the vulnerability of the grapevine to the spring frost.The aim of this study is to determine trends and changes in budburst date, their statistical characteristics at available stations in period 1961-2020 in Croatia. We focus on four grapevine varieties, two white (Gra&#353;evina and Chardonnay) and two red (Merlot and Plavac Mali) and performance of statistical models (GDD, Riou&#8217;s model and BRIN model) that predict budburst dates in the present climate. For this purpose an effect of the dormancy period and base temperature on the simulated budburst date have been explored. The study is further extended to future climatic conditions using statistical and numerical climate models. Therefore, a daily output from three CORDEX Regional Climate Models&#8217; (RCMs) simulations (CLMcom-CCLM4-8-17, SMHI-RCA4, CNRM-ALADIN5.3) for Croatian domain are used. All RCMs are forced by Global Climate Models (GCMs) with a moderate (RCP4.5) and a high-end (RCP8.5) green-house gass (GHG) scenario(s) and all the simulations have horizontal grid spacing of 0.11&#176;. Results indicate further earlier appearance of budburst regardless of varieties.

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Effects of GCM selection for regional climate modelling illustrated by the interactive tool GCMeval

10.5194/egusphere-egu2020-13441 ◽

2020 ◽

Author(s):

Oskar A. Landgren ◽

Kajsa Parding ◽

Andreas Dobler ◽

Carol F. McSweeney ◽

Rasmus Benestad ◽

...

Keyword(s):

Climate Models ◽

Global Climate ◽

Regional Climate ◽

Model Performance ◽

Global Climate Models ◽

Future Climate Change ◽

Historical Period ◽

Climate Modelling ◽

Temperature And Precipitation ◽

Skill Scores

With the increasing number of global climate models available, regional modellers have to make choices to select a manageable subset for downscaling. This limits the representation of both present day climate and future climate change compared to the full GCM ensemble.We present the interactive web-based tool called &#8220;GCMeval&#8221;, available at https://gcmeval.met.no. This tool lets you assign weights to different regions, seasons, climate variables, and skill scores and presents a ranking with model performance for a historical period. We demonstrate how the tool can be used to, for example, remove models with the largest historical biases for the selected criteria, or to optimise the spread. The weighting can be used to illustrate the sensitivity of the results to model choice.Based on the choice of regions and weights, the tool produces scatter plots of projected future temperature and precipitation and shows how the selected sub-ensemble compares to the full ensemble. The tool can also be used to evaluate ensemble selections "post-hoc", as demonstrated with examples from CORDEX.

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Application of SWAT in Hydrological Simulation of Complex Mountainous River Basin (Part II: Climate Change Impact Assessment)

Water ◽

10.3390/w13111548 ◽

2021 ◽

Vol 13 (11) ◽

pp. 1548

Author(s):

Suresh Marahatta ◽

Deepak Aryal ◽

Laxmi Prasad Devkota ◽

Utsav Bhattarai ◽

Dibesh Shrestha

Keyword(s):

Climate Change ◽

River Basin ◽

Climate Models ◽

Assessment Tool ◽

Swat Model ◽

Global Climate Models ◽

Climate Data ◽

The Future ◽

The Impact ◽

Mountainous River

This study aims at analysing the impact of climate change (CC) on the river hydrology of a complex mountainous river basin—the Budhigandaki River Basin (BRB)—using the Soil and Water Assessment Tool (SWAT) hydrological model that was calibrated and validated in Part I of this research. A relatively new approach of selecting global climate models (GCMs) for each of the two selected RCPs, 4.5 (stabilization scenario) and 8.5 (high emission scenario), representing four extreme cases (warm-wet, cold-wet, warm-dry, and cold-dry conditions), was applied. Future climate data was bias corrected using a quantile mapping method. The bias-corrected GCM data were forced into the SWAT model one at a time to simulate the future flows of BRB for three 30-year time windows: Immediate Future (2021–2050), Mid Future (2046–2075), and Far Future (2070–2099). The projected flows were compared with the corresponding monthly, seasonal, annual, and fractional differences of extreme flows of the simulated baseline period (1983–2012). The results showed that future long-term average annual flows are expected to increase in all climatic conditions for both RCPs compared to the baseline. The range of predicted changes in future monthly, seasonal, and annual flows shows high uncertainty. The comparative frequency analysis of the annual one-day-maximum and -minimum flows shows increased high flows and decreased low flows in the future. These results imply the necessity for design modifications in hydraulic structures as well as the preference of storage over run-of-river water resources development projects in the study basin from the perspective of climate resilience.

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CRI-HOM: A novel chemical mechanism for simulating Highly Oxygenated Organic Molecules (HOMs) in global chemistry-aerosol-climate models

10.5194/acp-2020-154 ◽

2020 ◽

Author(s):

James Weber ◽

Alexander Archibald ◽

Paul Griffiths ◽

Scott Archer-Nicholls ◽

Torsten Berndt ◽

...

Keyword(s):

Boreal Forest ◽

Radiative Forcing ◽

Organic Molecules ◽

Climate Models ◽

Global Climate Models ◽

Chemical Mechanism ◽

Atmospheric Composition ◽

Climate Modelling ◽

Particle Nucleation ◽

Peroxy Radicals

Abstract. We present here results from a new mechanism, CRI-HOM, which we have developed to simulate the formation of highly oxygenated organic molecules (HOMs) from the gas phase oxidation of α-pinene, one of the most widely emitted BVOCs by mass. This concise scheme adds 12 species and 66 reactions to the Common Representative Intermediates (CRI) mechanism v2.2 Reduction 5 and enables the representation of semi-explicit HOM treatment suitable for long term global chemistry- aerosol-climate modelling, within a comprehensive tropospheric chemical mechanism. The key features of the new mechanism are (i) representation of the autoxidation of peroxy radicals from the hydroxyl radical and ozone initiated reactions of α-pinene, (ii) formation of multiple generations of peroxy radicals, (iii) formation of accretion products (dimers) and (iv) isoprene-driven suppression of accretion product formation, as observed in experiments. The mechanism has been constructed through optimisation against a series of flow tube laboratory experiments. The mechanism predicts a HOM yield of 4–6 % under conditions of low to moderate NOx, in line with experimental observations, and reproduces qualitatively the decline in HOM yield and concentration at higher NOx. The mechanism gives a HOM yield that also increases with temperature, in line with observations, and our mechanism compares favourably to some of the limited observations of [HOM] observed in the boreal forest in Finland and in the south east USA. The reproduction of isoprene-driven suppression of HOMs is a key step forward as it enables global climate models to capture the interaction between the major BVOC species, along with the potential climatic feedbacks. This suppression is demonstrated when the mechanism is used to simulate atmospheric profiles over the boreal forest and rainforest; different isoprene concentrations result in different [HOM] distributions, illustrating the importance of BVOC interactions in atmospheric composition and climate. Finally particle nucleation rates calculated from [HOM] in present day and pre- industrial atmospheres suggest that sulphuric acid free nucleation can compete effectively with other nucleation pathways in the boreal forest, particularly in the pre-industrial, with important implications for the aerosol budget and radiative forcing.

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Performance of SEACLID/CORDEX-SEA multi-model experiments in simulating temperature and rainfall in Vietnam

Vietnam Journal of Earth Sciences ◽

10.15625/0866-7187/41/4/14259 ◽

2019 ◽

Vol 41 (4) ◽

pp. 374-387 ◽

Cited By ~ 1

Author(s):

Nguyen Thi Tuyet ◽

Ngo Duc Thanh ◽

Phan Van Tan

Keyword(s):

Southeast Asia ◽

Climate Models ◽

Global Climate ◽

Regional Climate ◽

Global Climate Models ◽

Red River ◽

Observation Data ◽

Red River Delta ◽

North Central ◽

Climate Downscaling

The study examined the performance of six regional climate experiments conducted under the framework of the Southeast Asia Regional Climate Downscaling/Coordinated Regional Climate Downscaling Experiment-Southeast Asia (SEACLID/CORDEX-SEA) project and their ensemble product (ENS) in simulating temperature at 2 m (T2m) and rainfall (R) in seven climatic sub-regions of Vietnam. The six experiments were named following the names of their driving Global Climate Models (GCMs), i.e., CNRM, CSIRO, ECEA, GFDL, HADG and MPI. The observation data for the period 1986–2005 from 66 stations in Vietnam were used to compare with the model outputs. Results showed that cold biases were prominent among the experiments and ENS well reproduced the seasonal cycle of temperature in the Northeast, Red River Delta, North Central and Central Highlands regions. For rainfall, all the experiments showed wet biases and CSIRO exhibited the best. A scoring system was elaborated to objectively rank the performance of the experiments and the ENS experiment was reported to be the best.

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Projected effects of vegetation feedback on drought characteristics of West Africa using a coupled regional land–vegetation–climate model

10.5194/hess-2019-319 ◽

2019 ◽

Author(s):

Muhammad Shafqat Mehboob ◽

Yeonjoo Kim ◽

Jaehyeong Lee ◽

Myoung-Jin Um ◽

Amir Erfanian ◽

...

Keyword(s):

West Africa ◽

Vegetation Dynamics ◽

Climate Models ◽

Climate Model ◽

Regional Climate ◽

Global Climate Models ◽

Congo Basin ◽

Area Index ◽

Vegetation Feedback ◽

Community Land Model

Abstract. This study investigates the projected effect of vegetation feedback on drought conditions in West Africa using a regional climate model coupled to the National Center for Atmospheric Research Community Land Model, the carbon-nitrogen (CN) module, and the dynamic vegetation (DV) module (RegCM-CLM-CN-DV). The role of vegetation feedback is examined based on simulations with and without the DV module. Simulations from four different global climate models are used as lateral boundary conditions (LBCs) for historical and future periods (i.e., historical: 1981–2000; future: 2081–2100). With utilizing the Standardized Precipitation Evapotranspiration Index (SPEI), we quantify the duration, frequency, and severity of droughts over the focal regions of the Sahel, the Gulf of Guinea, and the Congo Basin. With the vegetation dynamics being considered, future droughts become more prolonged and enhanced over the Sahel, whereas for the Guinea Gulf and Congo Basin, the trend is opposite. Additionally, we show that simulated annual leaf greenness (i.e., the Leaf Area Index) well-correlates with annual minimum SPEI, particularly over the Sahel, which is a transition zone, where the feedback between land-atmosphere is relatively strong. Furthermore, we note that our findings based on the ensemble mean are varying, but consistent among three different LBCs except for one LBC. Our results signify the importance of vegetation dynamics in predicting future droughts in West Africa, where the biosphere and atmosphere interactions play an important role in the regional climate setup.

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