Regional Climate Modeling for the Baltic Sea Region

2020 ◽  
Author(s):  
Erik Kjellström ◽  
Ole Bøssing Christensen
Keyword(s):  
Climate Change ◽  
Baltic Sea ◽  
Climate Models ◽  
Climate Modeling ◽  
Regional Climate ◽  
Regional Climate Modeling ◽  
Sea Surface ◽  
The Baltic Sea ◽  
Baltic Sea Region ◽  
The Baltic

Regional climate models (RCMs) are commonly used to provide detailed regional to local information for climate change assessments, impact studies, and work on climate change adaptation. The Baltic Sea region is well suited for RCM evaluation due to its complexity and good availability of observations. Evaluation of RCM performance over the Baltic Sea region suggests that: • Given appropriate boundary conditions, RCMs can reproduce many aspects of the climate in the Baltic Sea region. • High resolution improves the ability of RCMs to simulate significant processes in a realistic way. • When forced by global climate models (GCMs) with errors in their representation of the large-scale atmospheric circulation and/or sea surface conditions, performance of RCMs deteriorates. • Compared to GCMs, RCMs can add value on the regional scale, related to both the atmosphere and other parts of the climate system, such as the Baltic Sea, if appropriate coupled regional model systems are used. Future directions for regional climate modeling in the Baltic Sea region would involve testing and applying even more high-resolution, convection permitting, models to generally better represent climate features like heavy precipitation extremes. Also, phenomena more specific to the Baltic Sea region are expected to benefit from higher resolution (these include, for example, convective snowbands over the sea in winter). Continued work on better describing the fully coupled regional climate system involving the atmosphere and its interaction with the sea surface and land areas is also foreseen as beneficial. In this respect, atmospheric aerosols are important components that deserve more attention.

scholarly journals Coupled regional Earth system modelling in the Baltic Sea region

2021 ◽  
Author(s):  
Matthias Gröger ◽  
Christian Dieterich ◽  
Jari Haapala ◽  
Ha Thi Minh Ho-Hagemann ◽  
Stefan Hagemann ◽  
...  
Keyword(s):  
Climate Change ◽  
Baltic Sea ◽  
Regional Climate ◽  
Model Systems ◽  
Earth System ◽  
The Baltic Sea ◽  
Coupled Models ◽  
Baltic Sea Region ◽  
Ocean Models ◽  
The Baltic

Abstract. Non-linear responses to externally forced climate change are known to dampen or amplify the local climate impact due to complex cross compartmental feedback loops in the earth system. These feedbacks are less well represented in traditional standalone atmosphere and ocean models on which many of today's regional climate assessments rely on (e.g. EuroCordex, NOSCCA, BACC II). This promotes the development of regional climate models for the Baltic Sea region by coupling different compartments of the earth system into more comprehensive models. Coupled models more realistically represent feedback loops than the information imposed into the region by using prescribed boundary conditions, and thus, permit a higher degree of freedom. In the past, several coupled model systems have been developed for Europe and the Baltic Sea region. This article reviews recent progress of model systems that allow two way communication between atmosphere and ocean models, models for the land surface including the terrestrial biosphere, as well as wave models at the air sea interface and hydrology models for water cycle closure. However, several processes that have so far mostly been realized by one way coupling such as marine biogeochemistry, nutrient cycling and atmospheric chemistry (e.g. aerosols) are not considered here.Compared to uncoupled standalone models, coupled earth system models models can modify mean near surface air temperatures locally up to several degrees compared to their standalone atmospheric counterparts using prescribed surface boundary conditions. Over open ocean areas, the representation of small scale oceanic processes such as vertical mixing, and sea ice dynamics appear essential to accurately resolve the air sea heat exchange in the Baltic Sea region and can only be provided by online coupled high resolution ocean models. In addition, the coupling of wave models at the ocean-atmosphere interface allows a more explicit formulation of small-scale to microphysical processes with local feedbacks to water temperature and large scale processes such as oceanic upwelling. Over land, important climate feedbacks arise from dynamical terrestrial vegetation changes as well as the implementation of land use scenarios and afforestation/deforestation that further alter surface albedo, roughness length and evapotranspiration. Furthermore, a good representation of surface temperatures and roughness length over open sea and land areas is critical for the representation of climatic extremes like e.g. heavy precipitation, storms, or tropical nights, and appear to be sensitive to coupling.For the present-day climate, many coupled atmosphere-ocean and atmosphere-land surface models demonstrate added value with respect to single climate variables in particular when low quality boundary data were used in the respective standalone model. This makes coupled models a prospective tool for downscaling climate change scenarios from global climate models because these models often have large biases on the regional scale. However, the coupling of hydrology models for closing the water cycle remains problematic as the accuracy of precipitation provided by the atmosphere models is in most cases insufficient to realistically simulate the runoff to the Baltic Sea without bias adjustments.Many regional standalone ocean and atmosphere models are tuned to well represent present day climatologies rather than accurately simulate climate change. More research is necessary about how the regional climate sensitivity (e.g. the models’ response to a given change in global mean temperature) is affected by coupling and how the spread is altered in multi-model and multi-scenario ensembles of coupled models compared to uncoupled ones.

scholarly journals Coupled regional Earth system modeling in the Baltic Sea region

2021 ◽  
Vol 12 (3) ◽  
pp. 939-973
Author(s):  
Matthias Gröger ◽  
Christian Dieterich ◽  
Jari Haapala ◽  
Ha Thi Minh Ho-Hagemann ◽  
Stefan Hagemann ◽  
...  
Keyword(s):  
Climate Change ◽  
Baltic Sea ◽  
Regional Climate ◽  
Model Systems ◽  
Earth System ◽  
The Baltic Sea ◽  
Coupled Models ◽  
Baltic Sea Region ◽  
Ocean Models ◽  
The Baltic

Abstract. Nonlinear responses to externally forced climate change are known to dampen or amplify the local climate impact due to complex cross-compartmental feedback loops in the Earth system. These feedbacks are less well represented in the traditional stand-alone atmosphere and ocean models on which many of today's regional climate assessments rely (e.g., EURO-CORDEX, NOSCCA and BACC II). This has promoted the development of regional climate models for the Baltic Sea region by coupling different compartments of the Earth system into more comprehensive models. Coupled models more realistically represent feedback loops than the information imposed on the region by prescribed boundary conditions and, thus, permit more degrees of freedom. In the past, several coupled model systems have been developed for Europe and the Baltic Sea region. This article reviews recent progress on model systems that allow two-way communication between atmosphere and ocean models; models for the land surface, including the terrestrial biosphere; and wave models at the air–sea interface and hydrology models for water cycle closure. However, several processes that have mostly been realized by one-way coupling to date, such as marine biogeochemistry, nutrient cycling and atmospheric chemistry (e.g., aerosols), are not considered here. In contrast to uncoupled stand-alone models, coupled Earth system models can modify mean near-surface air temperatures locally by up to several degrees compared with their stand-alone atmospheric counterparts using prescribed surface boundary conditions. The representation of small-scale oceanic processes, such as vertical mixing and sea-ice dynamics, appears essential to accurately resolve the air–sea heat exchange over the Baltic Sea, and these parameters can only be provided by online coupled high-resolution ocean models. In addition, the coupling of wave models at the ocean–atmosphere interface allows for a more explicit formulation of small-scale to microphysical processes with local feedbacks to water temperature and large-scale processes such as oceanic upwelling. Over land, important climate feedbacks arise from dynamical terrestrial vegetation changes as well as the implementation of land-use scenarios and afforestation/deforestation that further alter surface albedo, roughness length and evapotranspiration. Furthermore, a good representation of surface temperatures and roughness length over open sea and land areas is critical for the representation of climatic extremes such as heavy precipitation, storms, or tropical nights (defined as nights where the daily minimum temperature does not fall below 20 ∘C), and these parameters appear to be sensitive to coupling. For the present-day climate, many coupled atmosphere–ocean and atmosphere–land surface models have demonstrated the added value of single climate variables, in particular when low-quality boundary data were used in the respective stand-alone model. This makes coupled models a prospective tool for downscaling climate change scenarios from global climate models because these models often have large biases on the regional scale. However, the coupling of hydrology models to close the water cycle remains problematic, as the accuracy of precipitation provided by atmosphere models is, in most cases, insufficient to realistically simulate the runoff to the Baltic Sea without bias adjustments. Many regional stand-alone ocean and atmosphere models are tuned to suitably represent present-day climatologies rather than to accurately simulate climate change. Therefore, more research is required into how the regional climate sensitivity (e.g., the models' response to a given change in global mean temperature) is affected by coupling and how the spread is altered in multi-model and multi-scenario ensembles of coupled models compared with uncoupled ones.

Projections for Temperature, Precipitation, Wind, and Snow in the Baltic Sea Region until 2100

2018 ◽  
Author(s):  
Ole Bøssing Christensen ◽  
Erik Kjellström
Keyword(s):  
Climate Change ◽  
Wind Speed ◽  
Baltic Sea ◽  
Climate Models ◽  
Global Climate Models ◽  
Anthropogenic Climate Change ◽  
The Baltic Sea ◽  
Baltic Sea Region ◽  
The Future ◽  
The Baltic

The ecosystems and the societies of the Baltic Sea region are quite sensitive to fluctuations in climate, and therefore it is expected that anthropogenic climate change will affect the region considerably. With numerical climate models, a large amount of projections of meteorological variables affected by anthropogenic climate change have been performed in the Baltic Sea region for periods reaching the end of this century.Existing global and regional climate model studies suggest that:• The future Baltic climate will get warmer, mostly so in winter. Changes increase with time or increasing emissions of greenhouse gases. There is a large spread between different models, but they all project warming. In the northern part of the region, temperature change will be higher than the global average warming.• Daily minimum temperatures will increase more than average temperature, particularly in winter.• Future average precipitation amounts will be larger than today. The relative increase is largest in winter. In summer, increases in the far north and decreases in the south are seen in most simulations. In the intermediate region, the sign of change is uncertain.• Precipitation extremes are expected to increase, though with a higher degree of uncertainty in magnitude compared to projected changes in temperature extremes.• Future changes in wind speed are highly dependent on changes in the large-scale circulation simulated by global climate models (GCMs). The results do not all agree, and it is not possible to assess whether there will be a general increase or decrease in wind speed in the future.• Only very small high-altitude mountain areas in a few simulations are projected to experience a reduction in winter snow amount of less than 50%. The southern half of the Baltic Sea region is projected to experience significant reductions in snow amount, with median reductions of around 75%.

scholarly journals Atmospheric regional climate projections for the Baltic Sea Region until 2100

2021 ◽  
Author(s):  
Ole B. Christensen ◽  
Erik Kjellström ◽  
Christian Dieterich ◽  
Matthias Gröger ◽  
H. E. Markus Meier
Keyword(s):  
Climate Change ◽  
Baltic Sea ◽  
Regional Climate Model ◽  
Climate Model ◽  
Regional Climate ◽  
Future Climate Change ◽  
Climate Projections ◽  
The Baltic Sea ◽  
Baltic Sea Region ◽  
The Baltic

Abstract. The Baltic Sea Region is very sensitive to climate change; it is a region with spatially varying climate and diverse ecosystems, but also under pressure due to high population in large parts of the area. Climate change impacts could easily exacerbate other anthropogenic stressors such as biodiversity stress from society and eutrophication of the Baltic Sea considerably. Therefore, there has been a focus on estimations of future climate change and its impacts in recent research. In this review paper, we will concentrate on a presentation of recent climate projections from both atmosphere-only and coupled atmosphere-ocean regional climate models. The recent regional climate model projections strengthen the picture from previous assessments. This includes a strong warming, in particular in the north in winter. Precipitation is projected to increase in the whole region apart from the southern half during summer. Consequently, the new results lend more credibility to estimates of uncertainties and robust features of future climate change. Furthermore, the larger number of scenarios gives opportunities to better address impacts of mitigation measures. The coupled atmosphere-ocean model locally modifies the climate change signal relative to that in the stand-alone atmosphere regional climate model. Differences are largest in areas where the coupled system arrives at different sea-surface temperatures and sea-ice conditions.

scholarly journals Human impacts and their interactions in the Baltic Sea region

2021 ◽  
Author(s):  
Marcus Reckermann ◽  
Anders Omstedt ◽  
Tarmo Soomere ◽  
Juris Aigars ◽  
Naveed Akhtar ◽  
...  
Keyword(s):  
Climate Change ◽  
Baltic Sea ◽  
Human Activities ◽  
Human Impacts ◽  
The Other ◽  
Indigenous Species ◽  
General Description ◽  
The Baltic Sea ◽  
Baltic Sea Region ◽  
The Baltic

Abstract. Coastal environments, in particular heavily populated semi-enclosed marginal seas and coasts like the Baltic Sea region, are stongly affected by human activities. A multitude of human impacts, including climate change, affects the different compartments of the environment, and these effects interact with each other. As part of the Baltic Earth Assessment Reports (BEAR), we present an inventory and discussion of different human-induced factors and processes affecting the environment of the Baltic Sea region, and their interrelations. Some are naturally occurring and modified by human activities (i.e. climate change, coastal processes, hypoxia, acidification, submarine groundwater discharges, marine ecosystems, non-indigenous species, land use and land cover), some are completely human-induced (i.e. agriculture, aquaculture, fisheries, river regulations, offshore wind farms, shipping, chemical contamination, dumped warfare agents, marine litter and microplastics, tourism, coastal management), and they are all interrelated to different degrees. We present a general description and analysis of the state of knowledge on these interrelations. Our main insight is that climate change has an overarching, integrating impact on all of the other factors and can be interpreted as a background effect, which has different implications for the other factors. Impacts on the environment and the human sphere can be roughly allocated to anthropogenic drivers such as food production, energy production, transport, industry and economy. We conclude that a sound management and regulation of human activities must be implemented in order to use and keep the environments and ecosystems of the Baltic Sea region sustainably in a good shape. This must balance the human needs, which exert tremendous pressures on the systems, as humans are the overwhelming driving force for almost all changes we see. The findings from this inventory of available information and analysis of the different factors and their interactions in the Baltic Sea region can largely be transferred to other comparable marginal and coastal seas in the world.

Implementation of NEMO v4.0.1 as ocean component for the regional climate modeling framework

2020 ◽  
Author(s):  
Janna Abalichin ◽  
Birte-Marie Ehlers ◽  
Frank Janssen
Keyword(s):  
Climate Change ◽  
Baltic Sea ◽  
North Sea ◽  
Climate Modeling ◽  
Regional Climate ◽  
Regional Climate Modeling ◽  
Water Levels ◽  
Climate Extreme ◽  
Modeling Framework ◽  
The Impact

<p>The ‘German Strategy for Adaptation to Climate Change’ (DAS) provides the political framework to climate change mitigation and adaptation in Germany. The associated ‘Adaption Action Plan’ envisages the establishment of an operational forecasting and projection service for climate, extreme weather and coastal and inland waterbodies. This service is intended to make use of a regional climate modeling framework, with NEMO v4.0.(1) as the ocean component. The atmospheric component will be provided by the German Weather Service (either the current weather forecasting model ICON or COSMO will be used) and will be coupled to NEMO after testing and calibration of NEMO on the regional scale.</p><p>The area of interest includes besides the North Sea and the Baltic Sea the entire North-West-Shelf to take into account cross-shelf transport, the water exchange between North Sea and Baltic Sea and the impact of North Atlantic weather systems on the internal dynamics of the seas. One focus area will be German Bight, well known for its large tidal flats, which make wetting & drying a desirable model feature, which will be tested in future. The used/implemented bathymetry includes the up to date measurements of the sea floor from the EMODNET network.</p><p>To achieve a proper description of the dynamics in this region the model has to be calibrated with regard to the timing and amplitude of the water levels in the coastal waters, the water inflow through the Danish straits, the thermal stratification as well as the seasonality and thickness of the sea ice in the Northern Baltic Sea.</p><p>These efforts are carried out in the pilot project ‘Projection Service for Waterways and Shipping’ (ProWaS).</p>

scholarly journals Regional Climate Modeling over South America: A Review

2013 ◽  
Vol 2013 ◽  
pp. 1-13 ◽  
Author(s):  
Silvina A. Solman
Keyword(s):  
Climate Change ◽  
South America ◽  
Climate Models ◽  
Climate Modeling ◽  
Regional Climate ◽  
Regional Climate Change ◽  
Regional Climate Models ◽  
Regional Climate Modeling ◽  
South American ◽  
Sensitivity Studies

This review summarizes the progress achieved on regional climate modeling activities over South America since the early efforts at the beginning of the 2000s until now. During the last 10 years, simulations with regional climate models (RCMs) have been performed for several purposes over the region. Early efforts were mainly focused on sensitivity studies to both physical mechanisms and technical aspects of RCMs. The last developments were focused mainly on providing high-resolution information on regional climate change. This paper describes the most outstanding contributions from the isolated efforts to the ongoing coordinated RCM activities in the framework of the CORDEX initiative, which represents a major endeavor to produce ensemble climate change projections at regional scales and allows exploring the associated range of uncertainties. The remaining challenges in modeling South American climate features are also discussed.

Sign in / Sign up

Export Citation Format

Share Document