Climate hazard indices projections based on CORDEX-CORE, CMIP5 and CMIP6 ensemble.

Author(s):

Erika Coppola ◽

Keyword(s):

Regional Climate ◽

Congo Basin ◽

Added Value ◽

Climate Projections ◽

Hazard Indices ◽

Future Time ◽

Climate Services ◽

North East ◽

The Impact ◽

Far Future

Under the CORDEX umbrella the CORDEX-CORE initiative has been developed that was able to produce an ensemble of two RCMs at 0.22&#176; resolution downscaling 3 GCMs for each of the 9 CORDEX domains for two climate scenarios the RCP2.6 and the RCP8.5. The CORDEX-CORE and the CMIP5 driving ensemble together with the most recently produced CMIP6 ensemble has been analyzed and several temperature, heat, wet and dry hazard indicators have been computed for the present day and mid and far future time slices.As a results CORDEX-CORE shows a better validation for several hazard indices due to the higher spatial resolution. For the far future time slice the 3 ensembles project an increase for all the temperature and heat indices under the RCC8.5 scenario. The highest values are always shown by the CMIP6 ensemble except that for Tx>35 &#176;C for which CORDEX-CORE projects higher warming. Extreme wet and flood prone maxima are projected by the regional ensemble over la Plata basin in South America , over the Congo basin in Africa, in east North America, north east Europe , India and Indochina, notably the regions where a better validation is obtained, whereas the global ensembles show quite small or not existent signal. Compound hazard hotspots based on heat and drought indicators have been identified in Central America, in the Amazon region, in the Mediterranean, South Africa, India and Australia since in all these regions a linear relation is shown by the heatwave and drought change signal. Although still limited the CORDEX-CORE initiative was able to produce high resolution climate projections with a quasi global coverage. This can be seen as a first step to foster collaboration among the global and regional climate community. The existence of the first of this kind ensemble together with the previous CORDEX 0.44 ensembles and the global ensemble is very valuable for climate impact assessment studies since can provide information on the mean and extreme regional climate projections but also more robust quantification on the model spread. All being an added value for the impact and climate services communities.

Regional climate simulations at kilometer-scale with RegCM4: Evaluation of precipitation and future projections

10.5194/egusphere-egu2020-9183 ◽

2020 ◽

Author(s):

Paolo Stocchi ◽

Emanuela Pichelli ◽

Erika Coppola ◽

Jose Abraham Torres Alvarez ◽

Filippo Giorgi

Keyword(s):

Global Climate Model ◽

Regional Climate ◽

Added Value ◽

Historical Period ◽

Climate Projections ◽

Model Errors ◽

Grid Spacing ◽

Climate Simulations ◽

Near Future ◽

Far Future

The recent increase in climate modeling activities at convection permitting scales (grid spacing under 4 km) has strongly been motivated by the increased computer capacities in the last years with the aim to reduce the model errors associated with parameterized convection and a more detailed representation of present and future regional climate. Some Regional climate projects addressing on convection permitting modeling simulations and projections have been recently implemented to make more robust conclusions on the added value of convection permitting simulation to future climate projections. Here, we present convection resolving climate simulations performed in the framework the European Climate Prediction System (EUCP) project, using the non-hydrostatic version of the RegCM model. The RegCM simulations have a grid spacing of 3 km, over three different regions (Pan-Alpine, Central Europe, and South-East Europe). These simulations were driven by initial and boundary conditions built from intermediate 12 km simulations driven by the global climate model (GCM) HadGEM2-ES. We considered three time slices each one of them covering a 10-year period, the historical (1996-2005), the near future (2041-2050) and the far future (2090-2099) under the RCP8.5 scenario. The high resolutions (3 km) simulations, over the historical period, are evaluated through comparison with available observations data sets (including in-situ and satellite-based observation of precipitation) and coarse resolution (12 km) simulation is used as benchmark. The kilometer-scale RegCM4.7 scenario (RCP8.5) simulations, driven by HadGEM2-ES, near future (2041-2050) and the far future (2090-2099), are also analyzed and presented, focusing on the future change in terms of mean precipitation, precipitation intensity and frequency and heavy precipitation on daily and hourly timescales in different seasons.

Realised added value in dynamical downscaling of Australian climate change

10.5194/egusphere-egu21-3855 ◽

2021 ◽

Author(s):

Giovanni Di Virgilio ◽

Jason P. Evans ◽

Alejandro Di Luca ◽

Michael R. Grose ◽

Vanessa Round ◽

...

Keyword(s):

Climate Change ◽

Climate Models ◽

Climate Adaptation ◽

Regional Climate ◽

Future Climate ◽

Added Value ◽

Climate Projections ◽

Eastern Australia ◽

Australian Alps ◽

Future Climate Projections

Coarse resolution global climate models (GCM) cannot resolve fine-scale drivers of regional climate, which is the scale where climate adaptation decisions are made. Regional climate models (RCMs) generate high-resolution projections by dynamically downscaling GCM outputs. However, evidence of where and when downscaling provides new information about both the current climate (added value, AV) and projected climate change signals, relative to driving data, is lacking. Seasons and locations where CORDEX-Australasia ERA-Interim and GCM-driven RCMs show AV for mean and extreme precipitation and temperature are identified. A new concept is introduced, &#8216;realised added value&#8217;, that identifies where and when RCMs simultaneously add value in the present climate and project a different climate change signal, thus suggesting plausible improvements in future climate projections by RCMs. ERA-Interim-driven RCMs add value to the simulation of summer-time mean precipitation, especially over northern and eastern Australia. GCM-driven RCMs show AV for precipitation over complex orography in south-eastern Australia during winter and widespread AV for mean and extreme minimum temperature during both seasons, especially over coastal and high-altitude areas. RCM projections of decreased winter rainfall over the Australian Alps and decreased summer rainfall over northern Australia are collocated with notable realised added value. Realised added value averaged across models, variables, seasons and statistics is evident across the majority of Australia and shows where plausible improvements in future climate projections are conferred by RCMs. This assessment of varying RCM capabilities to provide realised added value to GCM projections can be applied globally to inform climate adaptation and model development.

The impact of RCM formulation and resolution on simulated precipitation in Africa

10.5194/esd-2019-55 ◽

2019 ◽

Cited By ~ 2

Author(s):

Minchao Wu ◽

Grigory Nikulin ◽

Erik Kjellström ◽

Danijel Belušić ◽

Colin Jones ◽

...

Keyword(s):

Climate Models ◽

Regional Climate ◽

Regional Climate Models ◽

Horizontal Resolution ◽

Added Value ◽

Primary Control ◽

Model Formulation ◽

Simulated Precipitation ◽

Mean Climate ◽

Abstract. We investigate the impact of model formulation and horizontal resolution on the ability of Regional Climate Models (RCMs) to simulate precipitation in Africa. Two RCMs – SMHI-RCA4 and HCLIM38-ALADIN are utilized for downscaling the ERA-Interim reanalysis over Africa at four different resolutions: 25, 50, 100 and 200 km. Additionally to the two RCMs, two different configurations of the same RCA4 are used. Contrasting different RCMs, configurations and resolutions it is found that model formulation has the primary control over many aspects of the precipitation climatology in Africa. Patterns of spatial biases in seasonal mean precipitation are mostly defined by model formulation while the magnitude of the biases is controlled by resolution. In a similar way, the phase of the diurnal cycle is completely controlled by model formulation (convection scheme) while its amplitude is a function of resolution. Although higher resolution in many cases leads to smaller biases in the time mean climate, the impact of higher resolution is mixed. An improvement in one region/season (e.g. reduction of dry biases) often corresponds to a deterioration in another region/season (e.g. amplification of wet biases). The experiments confirm a pronounced and well known impact of higher resolution – a more realistic distribution of daily precipitation. Even if the time-mean climate is not always greatly sensitive to resolution, what the time-mean climate is made up of, higher order statistics, is sensitive. Therefore, the realism of the simulated precipitation increases as resolution increases. Our results show that improvements in the ability of RCMs to simulate precipitation in Africa compared to their driving reanalysis in many cases are simply related to model formulation and not necessarily to higher resolution. Such model formulation related improvements are strongly model dependent and in general cannot be considered as an added value of downscaling.

Climate Perspectives in the Intra–Americas Seas

Atmosphere ◽

10.3390/atmos11090959 ◽

2020 ◽

Vol 11 (9) ◽

pp. 959

Author(s):

Ana María Durán-Quesada ◽

Rogert Sorí ◽

Paulina Ordoñez ◽

Luis Gimeno

Keyword(s):

Climate Change ◽

Extreme Events ◽

Large Scale ◽

Negative Impact ◽

Current Knowledge ◽

Regional Climate ◽

Climate Projections ◽

Economic Activities ◽

Weather And Climate ◽

The Intra–Americas Seas region is known for its relevance to air–sea interaction processes, the contrast between large water masses and a relatively small continental area, and the occurrence of extreme events. The differing weather systems and the influence of variability at different spatio–temporal scales is a characteristic feature of the region. The impact of hydro–meteorological extreme events has played a huge importance for regional livelihood, having a mostly negative impact on socioeconomics. The frequency and intensity of heavy rainfall events and droughts are often discussed in terms of their impact on economic activities and access to water. Furthermore, future climate projections suggest that warming scenarios are likely to increase the frequency and intensity of extreme events, which poses a major threat to vulnerable communities. In a region where the economy is largely dependent on agriculture and the population is exposed to the impact of extremes, understanding the climate system is key to informed policymaking and management plans. A wealth of knowledge has been published on regional weather and climate, with a majority of studies focusing on specific components of the system. This study aims to provide an integral overview of regional weather and climate suitable for a wider community. Following the presentation of the general features of the region, a large scale is introduced outlining the main structures that affect regional climate. The most relevant climate features are briefly described, focusing on sea surface temperature, low–level circulation, and rainfall patterns. The impact of climate variability at the intra–seasonal, inter–annual, decadal, and multi–decadal scales is discussed. Climate change is considered in the regional context, based on current knowledge for natural and anthropogenic climate change. The present challenges in regional weather and climate studies have also been included in the concluding sections of this review. The overarching aim of this work is to leverage information that may be transferred efficiently to support decision–making processes and provide a solid foundation on regional weather and climate for professionals from different backgrounds.

Temperature and precipitation projections for Poland based on downscaled EuroCORDEX ensemble

10.5194/egusphere-egu2020-14899 ◽

2020 ◽

Author(s):

Joanna Struzewska ◽

Maciej Jefimow ◽

Paulina Jagiełło ◽

Maria Kłeczek ◽

Anahita Sattari ◽

...

Keyword(s):

Regional Climate ◽

Annual Rainfall ◽

Maximum Temperature ◽

Climate Indices ◽

Climate Projections ◽

Spatial And Temporal Variability ◽

Climate Change Scenarios ◽

North East ◽

The North ◽

Temperature And Precipitation

Regional climate projections are necessary to assess possible changes in the exposure and risk to allow planning the adaptation strategies.Projections of temperature and precipitation trends were developed using a consistent methodology and homogeneous datasets to address the needs of up-to-date climate change scenarios for Poland.The Euro-Cordex results with the resolution of 0.11deg (about 12.5km) for RCP4.5 and RCP8.5 were downscaled based on various historical gridded datasets (EOBS, ERA5, UERRA and data from IMWM).Ensemble analysis was undertaken to assess the projection uncertainty and ensemble mean were calculated for base parameters (daily average, minimum, and maximum temperature and daily precipitation sum) as well as for the number of climate indices.We will present spatial and temporal variability of selected climate indices over Poland for subsequent decades. Increase of the annual average temperature is due to the rise in the number of hot days and the reduction of the number of frost days. All temperature indices are characterized by statistically significant trends, strongest for RCP8.5. The most pronounced changes in the frequency and amount of precipitation occur in the north-east of Poland. The total number of days with precipitation increases slightly. The increase in the annual rainfall is due to the increase in the number of days with extreme precipitation.Results are presented via an interactive web portal. Further analysis includes the development of projection for solar radiation, wind speed, humidity and snow cover.

Assessment of the impacts of climate change on maize production in the Wami Ruvu basin of Tanzania

Journal of Water and Climate Change ◽

10.2166/wcc.2016.055 ◽

2016 ◽

Vol 8 (1) ◽

pp. 142-164 ◽

Cited By ~ 3

Author(s):

Philbert Luhunga ◽

Ladslaus Chang'a ◽

George Djolov

Keyword(s):

Climate Change ◽

Climate Models ◽

Regional Climate ◽

Climate Projections ◽

Intergovernmental Panel ◽

Lower Altitude ◽

Rcp 8.5 ◽

Maize Yields ◽

The Impact ◽

Impacts Of Climate Change

The IPCC (Intergovernmental Panel on Climate Change) assessment reports confirm that climate change will hit developing countries the hardest. Adaption is on the agenda of many countries around the world. However, before devising adaption strategies, it is crucial to assess and understand the impacts of climate change at regional and local scales. In this study, the impact of climate change on rain-fed maize (Zea mays) production in the Wami-Ruvu basin of Tanzania was evaluated using the Decision Support System for Agro-technological Transfer. The model was fed with daily minimum and maximum temperatures, rainfall and solar radiation for current climate conditions (1971–2000) as well as future climate projections (2010–2099) for two Representative Concentration Pathways: RCP 4.5 and RCP 8.5. These data were derived from three high-resolution regional climate models, used in the Coordinated Regional Climate Downscaling Experiment program. Results showed that due to climate change future maize yields over the Wami-Ruvu basin will slightly increase relative to the baseline during the current century under RCP 4.5 and RCP 8.5. However, maize yields will decline in the mid and end centuries. The spatial distribution showed that high decline in maize yields are projected over lower altitude regions due to projected increase in temperatures in those areas.

Evaluation of the impacts of climate variability on rainfed maize production over the Wami-Ruvu basin of Tanzania

Journal of Water and Climate Change ◽

10.2166/wcc.2017.036 ◽

2017 ◽

Vol 9 (1) ◽

pp. 207-222 ◽

Author(s):

Philbert Luhunga

Keyword(s):

Climate Variability ◽

Climate Models ◽

Pearson Correlation ◽

Regional Climate ◽

Maximum Temperature ◽

Climate Projections ◽

Historical Climate ◽

Climate Simulations ◽

Maize Yields ◽

AbstractIn this study, the impact of inter-seasonal climate variability on rainfed maize (Zea mays) production over the Wami-Ruvu basin of Tanzania is evaluated. Daily high-resolution climate simulations from the Coordinated Regional Climate Downscaling Experiment_Regional Climate Models (CORDEX_RCMs) are used to drive the Decision Support System for Agro-technological Transfer (DSSAT) to simulate maize yields. Climate simulations for the base period of 35 years (1971–2005) are used to drive DSSAT to simulate maize yields during the historical climate. On the other hand, climate projections for the period 2010–2039 (current), 2040–2069 (mid), and 2070–2099 centuries for two Representative Concentration Pathway (RCP45 and 85) emission scenarios are used to drive DSSAT to simulate maize yields in respective centuries. Statistical approaches based on Pearson correlation coefficient and the coefficients of determination are used in the analysis. Results show that rainfall, maximum temperature, and solar radiation are the most important climate variables that determine variation in rainfed maize yields over the Wami-Ruvu basin of Tanzania. They explain the variability in maize yields in historical climate condition (1971–2005), present century under RCP 4.5, and mid and end centuries under both RCP 4.5 and RCP 8.5.

A Statistical–Dynamical Methodology to Downscale Regional Climate Projections to Urban Scale

Journal of Applied Meteorology and Climatology ◽

10.1175/jamc-d-19-0104.1 ◽

2020 ◽

Vol 59 (6) ◽

pp. 1109-1123 ◽

Author(s):

François DuchÊne ◽

Bert Van Schaeybroeck ◽

Steven Caluwaerts ◽

Rozemien De Troch ◽

Rafiq Hamdi ◽

...

Keyword(s):

Land Surface ◽

Climate Models ◽

Dynamical Downscaling ◽

Heat Waves ◽

Regional Climate ◽

Wave Number ◽

Surface Model ◽

Climate Projections ◽

Short Period ◽

AbstractThe demand of city planners for quantitative information on the impact of climate change on the urban environment is increasing. However, such information is usually extracted from decadelong climate projections generated with global or regional climate models (RCMs). Because of their coarse resolution and unsuitable physical parameterization, however, their model output is not adequate to be used at city scale. A full dynamical downscaling to city level, on the other hand, is computationally too expensive for climatological time scales. A statistical–dynamical computationally inexpensive method is therefore proposed that approximates well the behavior of the full dynamical downscaling approach. The approach downscales RCM simulations using the combination of an RCM at high resolution (H-RES) and a land surface model (LSM). The method involves the setup of a database of urban signatures by running an H-RES RCM with and without urban parameterization for a relatively short period. Using an analog approach, these signatures are first selectively added to the long-term RCM data, which are then used as forcing for an LSM using an urban parameterization in a stand-alone mode. A comparison with a full dynamical downscaling approach is presented for the city of Brussels, Belgium, for 30 summers with the combined ALADIN–AROME model (ALARO-0) coupled to the Surface Externalisée model (SURFEX) as H-RES RCM and SURFEX as LSM. The average bias of the nocturnal urban heat island during heat waves is vanishingly small, and the RMSE is strongly reduced. Not only is the statistical–dynamical approach able to correct the heat-wave number and intensities, it can also improve intervariable correlations and multivariate and temporally correlated indices, such as Humidex.

Physical and biogeochemical impacts of RCP8.5 scenario in the Peru upwelling system

10.5194/bg-2020-4 ◽

2020 ◽

Author(s):

Vincent Echevin ◽

Manon Gévaudan ◽

Dante Espinoza-Morriberon ◽

Jorge Tam ◽

Olivier Aumont ◽

...

Keyword(s):

Climate Change ◽

Coastal Upwelling ◽

Current System ◽

Regional Climate ◽

Physical Parameters ◽

Climate Projections ◽

Surface Cooling ◽

Humboldt Current ◽

Upwelling System ◽

Abstract. The northern Humboldt current system (NHCS or Peru upwelling system) sustains the world's largest small pelagic fishery. While a nearshore surface cooling has been observed off southern Peru in recent decades, there is still considerable debate on the impact of climate change on the regional ecosystem. This calls for more accurate regional climate projections of the 21st century, using adapted tools such as regional eddy-resolving coupled biophysical models. In this study 3 coarse-grid Earth System Models (ESMs) from the Coupled Model Intercomparison Project (CMIP5) are selected based on their biogeochemical biases upstream of the NHCS and simulations for the so-called business-as-usual RCP8.5 climate scenario are dynamically downscaled at 10 km resolution in the NHCS. The impact of regional climate change on temperature, coastal upwelling, nutrient content, deoxygenation and the planktonic ecosystem is documented. We find that the downscaling approach allows to correct major physical and biogeochemical biases of the ESMs. All regional simulations display a surface warming regardless of the coastal upwelling trends. Contrasted evolutions of the NHCS oxygen minimum zone and enhanced stratification of phytoplankton are found in the coastal region. Whereas trends of downscaled physical parameters are consistent with ESM trends, downscaled biogeochemical trends differ markedly. These results suggest that more realism of the ESMs is needed in the eastern equatorial Pacific to gain robustness in the projection of regional trends in the NHCS.

WRF Sensitivity for Seasonal Climate Simulations of Precipitation Fields on the CORDEX South America Domain

Atmosphere ◽

10.3390/atmos13010107 ◽

2022 ◽

Vol 13 (1) ◽

pp. 107

Author(s):

Helber Barros Gomes ◽

Maria Cristina Lemos da Silva ◽

Henrique de Melo Jorge Barbosa ◽

Tércio Ambrizzi ◽

Hakki Baltaci ◽

...

Keyword(s):

South America ◽

Numerical Models ◽

Regional Climate ◽

Wrf Model ◽

Added Value ◽

Climate Projections ◽

South American ◽

Climate Forecasting ◽

Climate Simulations ◽

Simulated Precipitation

Dynamic numerical models of the atmosphere are the main tools used for weather and climate forecasting as well as climate projections. Thus, this work evaluated the systematic errors and areas with large uncertainties in precipitation over the South American continent (SAC) based on regional climate simulations with the weather research and forecasting (WRF) model. Ten simulations using different convective, radiation, and microphysical schemes, and an ensemble mean among them, were performed with a resolution of 50 km, covering the CORDEX-South America domain. First, the seasonal precipitation variability and its differences were discussed. Then, its annual cycle was investigated through nine sub-domains on the SAC (AMZN, AMZS, NEBN, NEBS, SE, SURU, CHAC, PEQU, and TOTL). The Taylor Diagrams were used to assess the sensitivity of the model to different parameterizations and its ability to reproduce the simulated precipitation patterns. The results showed that the WRF simulations were better than the ERA-interim (ERAI) reanalysis when compared to the TRMM, showing the added value of dynamic downscaling. For all sub-domains the best result was obtained with the ensemble compared to the satellite TRMM. The largest errors were observed in the SURU and CHAC regions, and with the greatest dispersion of members during the rainy season. On the other hand, the best results were found in the AMZS, NEBS, and TOTL regions.