Future response of precipitation extremes over the Nordic region in a convection-permitting regional climate model

There is an increased need for more detailed climate information from impact researchers, stakeholders and policy makers for regional-to-local climate change assessments. In order to design relevant and informative planning strategies on these scales it is important to have reliable climate data and information on high spatial O(1km) and temporal (daily to sub-daily) scales. Such high-resolution data is also beneficial for climate impact modellers as input to their models, e.g. hydrological or urban models that operate on regional to local scales. It has been established that regional climate models (RCMs) provide added value compared to coarser global climate models (GCMs) or re-analysis (e.g. ERA-Interim). However, RCMs with standard spatial resolution O(10 &#8722; 50km) still suffer from inadequacies in representing important regional-to-local climate phenomena and characteristics, both from the implied &#8221;smoothening&#8221; effect within each grid cell which limits the representation of fine scale surface forcings, and the need to parameterize small-scale processes like atmospheric convection. The latter particularly invokes uncertainties in future climate responses of short-duration precipitation extremes such as flash-floods. Here, we compare 20-year simulations with a very high resolution (3 km grid spacing) convection permitting regional climate model (CPRCM) with a standard high-resolution (12 km grid spacing) convection parameterized RCM and their abilities to simulate the climate characteristics of the Nordic region in Europe, with particular focus on precipitation extremes. The study covers both recent past (with boundary data from ERA-Interim and the EC-Earth GCM) and the end of the 21st century (boundary data from EC-Earth using the RCP8.5 radiative forcing scenario). The high model grid resolution combined with the extensive simulated time period which enables assessment on climatological time scales makes this study one of very few for this region.

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Evaluation of extreme precipitation over the Nordic region using a convection-permitting regional climate model

10.5194/egusphere-egu2020-10506 ◽

2020 ◽

Author(s):

Erika Toivonen ◽

Danijel Belušić ◽

Emma Dybro Thomassen ◽

Peter Berg ◽

Ole Bøssing Christensen ◽

...

Keyword(s):

High Resolution ◽

Regional Climate Model ◽

Extreme Precipitation ◽

Climate Model ◽

Daily Precipitation ◽

Regional Climate ◽

Precipitation Extremes ◽

Nordic Region ◽

Mesh Resolution ◽

Grid Mesh

Extreme precipitation events have a major impact upon our society. Although many studies have indicated that it is likely that the frequency of such events will increase in a warmer climate, little has been done to assess changes in extreme precipitation at a sub-daily scale. Recently, there is more and more evidence that high-resolution convection-permitting models (CPMs) (grid-mesh typically < 4 km) can represent especially short-duration precipitation extremes more accurately when compared with coarser-resolution regional climate models (RCMs).This study investigates sub-daily and daily precipitation characteristics based on hourly output data from the HARMONIE-Climate model at 3-km and 12-km grid-mesh resolution over the Nordic region between 1998 and 2018. The RCM modelling chain uses the ERA-Interim reanalysis to drive a 12-km grid-mesh simulation which is further downscaled to 3-km grid-mesh resolution using a non-hydrostatic model set-up.The statistical properties of the modeled extreme precipitation are compared to several sub-daily and daily observational products, including gridded and in-situ gauge data, from April to September. We investigate the skill of the model to represent different aspects of the frequency and intensity of extreme precipitation as well as intensity&#8211;duration&#8211;frequency (IDF) curves that are commonly used to investigate short duration extremes from an urban planning perspective. The high grid resolution combined with the 20-year-long simulation period allows for a robust assessment at a climatological time scale and enables us to examine the added value of high-resolution CPM in reproducing precipitation extremes over the Nordic region. Based on the tentative results, the high-resolution CPM can realistically capture the characteristics of precipitation extremes, for instance, in terms of improved diurnal cycle and maximum intensities of sub-daily precipitation.

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REMOLAND: New high-resolution surface boundary data for the regional climate model REMO and their impacts

10.5194/egusphere-egu2020-3005 ◽

2020 ◽

Author(s):

Katrin Ziegler ◽

Felix Pollinger ◽

Daniel Abel ◽

Heiko Paeth

Keyword(s):

High Resolution ◽

Regional Climate Model ◽

Land Surface ◽

Climate Models ◽

Climate Model ◽

Regional Climate ◽

Regional Climate Models ◽

Data Sets ◽

Surface Boundary ◽

Local Climate

In cooperation with the Climate Service Center Germany (GERICS) we want to improve the land surface module in the regional climate model REMO. Due to the need of high-resolution regional climate models to get information about local climate change, new data and new processes have to be integrated in these models. Based on the REMO2015 version and focusing on EUR-CORDEX region we included and compared five different high-resolution topographic data sets. To improve the thermal and hydrological processes in the model&#8217;s soil we also tested three new soil data sets with a much higher spatial resolution and with new parameters for a new soil parameterization.

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The Value of High-Resolution Met Office Regional Climate Models in the Simulation of Multihourly Precipitation Extremes

Journal of Climate ◽

10.1175/jcli-d-13-00723.1 ◽

2014 ◽

Vol 27 (16) ◽

pp. 6155-6174 ◽

Cited By ~ 93

Author(s):

Steven C. Chan ◽

Elizabeth J. Kendon ◽

Hayley J. Fowler ◽

Stephen Blenkinsop ◽

Nigel M. Roberts ◽

...

Keyword(s):

High Resolution ◽

Time Scales ◽

Return Period ◽

Extreme Events ◽

Climate Models ◽

Climate Model ◽

Regional Climate ◽

Value Theory ◽

Precipitation Extremes ◽

Return Levels

Abstract Extreme value theory is used as a diagnostic for two high-resolution (12-km parameterized convection and 1.5-km explicit convection) Met Office regional climate model (RCM) simulations. On subdaily time scales, the 12-km simulation has weaker June–August (JJA) short-return-period return levels than the 1.5-km RCM, yet the 12-km RCM has overly large high return levels. Comparisons with observations indicate that the 1.5-km RCM is more successful than the 12-km RCM in representing (multi)hourly JJA very extreme events. As accumulation periods increase toward daily time scales, the erroneous 12-km precipitation extremes become more comparable with the observations and the 1.5-km RCM. The 12-km RCM fails to capture the observed low sensitivity of the growth rate to accumulation period changes, which is successfully captured by the 1.5-km RCM. Both simulations have comparable December–February (DJF) extremes, but the DJF extremes are generally weaker than in JJA at daily or shorter time scales. Case studies indicate that “gridpoint storms” are one of the causes of unrealistic very extreme events in the 12-km RCM. Caution is needed in interpreting the realism of 12-km RCM JJA extremes, including short-return-period events, which have return values closer to observations. There is clear evidence that the 1.5-km RCM has a higher degree of realism than the 12-km RCM in the simulation of JJA extremes.

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Realism of Rainfall in a Very High-Resolution Regional Climate Model

Journal of Climate ◽

10.1175/jcli-d-11-00562.1 ◽

2012 ◽

Vol 25 (17) ◽

pp. 5791-5806 ◽

Cited By ~ 232

Author(s):

Elizabeth J. Kendon ◽

Nigel M. Roberts ◽

Catherine A. Senior ◽

Malcolm J. Roberts

Keyword(s):

United Kingdom ◽

High Resolution ◽

Regional Climate Model ◽

Climate Models ◽

Climate Model ◽

Regional Climate ◽

Heavy Rain ◽

Spatial Extent ◽

Hourly Rainfall ◽

Very High

Abstract The realistic representation of rainfall on the local scale in climate models remains a key challenge. Realism encompasses the full spatial and temporal structure of rainfall, and is a key indicator of model skill in representing the underlying processes. In particular, if rainfall is more realistic in a climate model, there is greater confidence in its projections of future change. In this study, the realism of rainfall in a very high-resolution (1.5 km) regional climate model (RCM) is compared to a coarser-resolution 12-km RCM. This is the first time a convection-permitting model has been run for an extended period (1989–2008) over a region of the United Kingdom, allowing the characteristics of rainfall to be evaluated in a climatological sense. In particular, the duration and spatial extent of hourly rainfall across the southern United Kingdom is examined, with a key focus on heavy rainfall. Rainfall in the 1.5-km RCM is found to be much more realistic than in the 12-km RCM. In the 12-km RCM, heavy rain events are not heavy enough, and tend to be too persistent and widespread. While the 1.5-km model does have a tendency for heavy rain to be too intense, it still gives a much better representation of its duration and spatial extent. Long-standing problems in climate models, such as the tendency for too much persistent light rain and errors in the diurnal cycle, are also considerably reduced in the 1.5-km RCM. Biases in the 12-km RCM appear to be linked to deficiencies in the representation of convection.

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Effects of coastal topography on climate: high-resolution simulation with a regional climate model

Climate Research ◽

10.3354/cr01077 ◽

2012 ◽

Vol 52 ◽

pp. 159-174 ◽

Cited By ~ 26

Author(s):

B Önol

Keyword(s):

High Resolution ◽

Regional Climate Model ◽

Climate Model ◽

Regional Climate ◽

Resolution Simulation ◽

Coastal Topography

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Regional Climate Model Inter-Comparison for Antarctica within a Data Science Framework

10.5194/egusphere-egu21-4892 ◽

2021 ◽

Author(s):

Jeremy Carter ◽

Amber Leeson ◽

Andrew Orr ◽

Christoph Kittel ◽

Melchior van Wessem

Keyword(s):

Regional Climate Model ◽

Climate Models ◽

Climate Model ◽

Regional Climate ◽

Regional Climate Models ◽

Future Climate Change ◽

Near Surface ◽

Virtual Lab ◽

Model Variability ◽

The Antarctic

Understanding the surface climatology of the Antarctic ice sheet is essential if we are to adequately predict its response to future climate change. This includes both primary impacts such as increased ice melting and secondary impacts such as ice shelf collapse events. Given its size, and inhospitable environment, weather stations on Antarctica are sparse. Thus, we rely on regional climate models to 1) develop our understanding of how the climate of Antarctica varies in both time and space and 2) provide data to use as context for remote sensing studies and forcing for dynamical process models. Given that there are a number of different regional climate models available that explicitly simulate Antarctic climate, understanding inter- and intra model variability is important.Here, inter- and intra-model variability in Antarctic-wide regional climate model output is assessed for: snowfall; rainfall; snowmelt and near-surface air temperature within a cloud-based virtual lab framework. State-of-the-art regional climate model runs from the Antarctic-CORDEX project using the RACMO, MAR and MetUM models are used, together with the ERA5 and ERA-Interim reanalyses products. Multiple simulations using the same model and domain boundary but run at either different spatial resolutions or with different driving data are used. Traditional analysis techniques are exploited and the question of potential added value from more modern and involved methods such as the use of Gaussian Processes is investigated. The advantages of using a virtual lab in a cloud based environment for increasing transparency and reproducibility, are demonstrated, with a view to ultimately make the code and methods used widely available for other research groups.

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