Capturing the Atlantic cold tongue and coastal upwelling in an intermediate-level ocean model coupled to a regional climate model

Abstract. Convective snow bands develop in response to a cold air outbreak from the continent or the frozen sea over the open water surface of lakes or seas. The comparatively warm water body triggers shallow convection due to increased heat and moisture fluxes. Strong winds can align with this convection into wind-parallel cloud bands, which appear stationary as the wind direction remains consistent for the time period of the snow band event, delivering enduring snow precipitation at the approaching coast. The statistical analysis of a dataset from an 11-year high-resolution atmospheric regional climate model (RCA4) indicated 4 to 7 days a year of moderate to highly favourable conditions for the development of convective snow bands in the Baltic Sea region. The heaviest and most frequent lake effect snow was affecting the regions of Gävle and Västervik (along the Swedish east coast) as well as Gdansk (along the Polish coast). However, the hourly precipitation rate is often higher in Gävle than in the Västervik region. Two case studies comparing five different RCA4 model setups have shown that the Rossby Centre atmospheric regional climate model RCA4 provides a superior representation of the sea surface with more accurate sea surface temperature (SST) values when coupled to the ice–ocean model NEMO as opposed to the forcing by the ERA-40 reanalysis data. The refinement of the resolution of the atmospheric model component leads, especially in the horizontal direction, to significant improvement in the representation of the mesoscale circulation process as well as the local precipitation rate and area by the model.

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Assessment of Indian summer monsoon variability in a regional climate model coupled to a slab ocean model

Theoretical and Applied Climatology ◽

10.1007/s00704-019-02951-4 ◽

2019 ◽

Vol 138 (3-4) ◽

pp. 1939-1949

Author(s):

Uppara Umakanth ◽

Amit P. Kesarkar

Keyword(s):

Regional Climate Model ◽

Summer Monsoon ◽

Indian Summer Monsoon ◽

Climate Model ◽

Regional Climate ◽

Ocean Model ◽

Monsoon Variability ◽

Slab Ocean

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The COSMO-CLM 4.8 regional climate model coupled to regional ocean, land surface and global earth system models using OASIS3-MCT: description and performance

Geoscientific Model Development ◽

10.5194/gmd-10-1549-2017 ◽

2017 ◽

Vol 10 (4) ◽

pp. 1549-1586 ◽

Cited By ~ 15

Author(s):

Andreas Will ◽

Naveed Akhtar ◽

Jennifer Brauch ◽

Marcus Breil ◽

Edouard Davin ◽

...

Keyword(s):

Regional Climate Model ◽

Direct Cost ◽

Land Surface ◽

Climate Model ◽

Regional Climate ◽

Ocean Model ◽

Earth System ◽

Climate System Model ◽

Community Land Model ◽

Computational Performance

Abstract. We developed a coupled regional climate system model based on the CCLM regional climate model. Within this model system, using OASIS3-MCT as a coupler, CCLM can be coupled to two land surface models (the Community Land Model (CLM) and VEG3D), the NEMO-MED12 regional ocean model for the Mediterranean Sea, two ocean models for the North and Baltic seas (NEMO-NORDIC and TRIMNP+CICE) and the MPI-ESM Earth system model.We first present the different model components and the unified OASIS3-MCT interface which handles all couplings in a consistent way, minimising the model source code modifications and defining the physical and numerical aspects of the couplings. We also address specific coupling issues like the handling of different domains, multiple usage of the MCT library and exchange of 3-D fields.We analyse and compare the computational performance of the different couplings based on real-case simulations over Europe. The usage of the LUCIA tool implemented in OASIS3-MCT enables the quantification of the contributions of the coupled components to the overall coupling cost. These individual contributions are (1) cost of the model(s) coupled, (2) direct cost of coupling including horizontal interpolation and communication between the components, (3) load imbalance, (4) cost of different usage of processors by CCLM in coupled and stand-alone mode and (5) residual cost including i.a. CCLM additional computations.Finally a procedure for finding an optimum processor configuration for each of the couplings was developed considering the time to solution, computing cost and parallel efficiency of the simulation. The optimum configurations are presented for sequential, concurrent and mixed (sequential+concurrent) coupling layouts. The procedure applied can be regarded as independent of the specific coupling layout and coupling details.We found that the direct cost of coupling, i.e. communications and horizontal interpolation, in OASIS3-MCT remains below 7 % of the CCLM stand-alone cost for all couplings investigated. This is in particular true for the exchange of 450 2-D fields between CCLM and MPI-ESM. We identified remaining limitations in the coupling strategies and discuss possible future improvements of the computational efficiency.

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Characteristics of Convective Snow Bands in the Baltic Sea Area

10.5194/esd-2016-43 ◽

2016 ◽

Author(s):

Julia Jeworrek ◽

Lichuan Wu ◽

Christian Dieterich ◽

Anna Rutgersson

Keyword(s):

Baltic Sea ◽

Regional Climate Model ◽

Climate Model ◽

Regional Climate ◽

Open Water ◽

Ocean Model ◽

Precipitation Rate ◽

Shallow Convection ◽

The Baltic Sea ◽

The Baltic

Abstract. Convective snow bands develop in response to a cold air outbreak from the continent over the open water surface of lakes or seas. The comparatively warm water body triggers shallow convection due to increased heat and moisture fluxes. Strong winds can align with this convection into wind-parallel cloud bands, which appear stationary as the wind direction remains consistent for the time period of the snow band event, delivering enduring snow precipitation at the approaching coast. The statistical analysis of a dataset from an 11-year high resolution atmospheric regional climate model (RCA4) indicated 4 to 7 days a year of moderate to highly favorable conditions for the development of convective snow bands in the Baltic Sea region. The heaviest and most frequent lake effect snow was affecting the regions of Gävle and Västervik (along the Swedish east coast) as well as Gdansk (along the Polish coast). However, the hourly precipitation rate is often higher in Gävle than in the Västervik region. Two case studies comparing five different RCA4 model setups have shown that the Rossby Centre atmospheric regional climate model RCA4 provides a superior representation of the sea surface with more accurate SST values when coupled to the ice-ocean model NEMO as opposed to the forcing by the ERA-40 reanalysis data. The refinement of the resolution of the atmospheric model component lead especially in horizontal direction to significant improvement on the representation of the mesoscale circulation process as well as the local precipitation rate and area by the model.

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Future changes in extreme precipitation in central Serbia

Journal of Hydrology and Hydromechanics ◽

10.2478/johh-2021-0006 ◽

2021 ◽

Vol 69 (2) ◽

pp. 196-208

Author(s):

Ranka Erić ◽

Ratko Kadović ◽

Vladimir Đurđević ◽

Vesna Đukić

Keyword(s):

Regional Climate Model ◽

Extreme Precipitation ◽

Climate Model ◽

Daily Precipitation ◽

Regional Climate ◽

Ocean Model ◽

Data Sets ◽

Observation Data ◽

Historical Observation ◽

Projected Changes

Abstract This paper presents the results of a study focused on the projected changes in extreme precipitation during the 21st century in Central Serbia. The changes are investigated on the basis of historical and modelled data sets of daily precipitation. The historical observation data were recorded at 18 synoptic weather stations in Central Serbia and modelled data were extracted from the regional climate model EBU-POM (Eta Belgrade University-Princeton Ocean Model) under the A1B scenario. The average number of days in a year with precipition ≥ 20, 30, 40 and 50 mm (R20, R30, R40 and R50), the share of daily precipitation above the 20, 30, 40 and 50 mm (P20, P30, P40, P50) in the total annual precipitation and the monthly distribution of these heavy daily precipitation are used as indices of changes in extreme precipitation. These indices, for the three periods 2011–2040, 2041–2070 and 2071–2100, are determined and compared with those obtained for the historical reference period 1961–1990. The results have shown that the main changes in extreme precipitation in Central Serbia will be in their spatial distribution, and the uncertainty of the occurrence of extreme events will decrease. In the future the increase will be more pronounced than the decrease of these indices. We strongly emphasize the benefit of this paper for both the prevention of natural disasters in the study area and for the improvement of the regional climate model.

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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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Qinghai-Xizang (Tibetan) Plateau climate simulation using the regional climate model RegCM3

Climate Research ◽

10.3354/cr01167 ◽

2013 ◽

Vol 57 (3) ◽

pp. 173-186 ◽

Cited By ~ 18

Author(s):

X Wang ◽

M Yang ◽

G Wan ◽

X Chen ◽

G Pang

Keyword(s):

Tibetan Plateau ◽

Regional Climate Model ◽

Climate Model ◽

Regional Climate ◽

Climate Simulation

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Evaluation of net shortwave radiation over China with a regional climate model

Climate Research ◽

10.3354/cr01598 ◽

2020 ◽

Vol 80 (2) ◽

pp. 147-163

Author(s):

X Liu ◽

Y Kang ◽

Q Liu ◽

Z Guo ◽

Y Chen ◽

...

Keyword(s):

Regional Climate Model ◽

Climate Model ◽

Regional Climate ◽

Radiant Energy ◽

Energy System ◽

Radiation Budget ◽

Shortwave Radiation ◽

Monsoon Region ◽

Clear Sky ◽

Sky Conditions

The regional climate model RegCM version 4.6, developed by the European Centre for Medium-Range Weather Forecasts Reanalysis, was used to simulate the radiation budget over China. Clouds and the Earth’s Radiant Energy System (CERES) satellite data were utilized to evaluate the simulation results based on 4 radiative components: net shortwave (NSW) radiation at the surface of the earth and top of the atmosphere (TOA) under all-sky and clear-sky conditions. The performance of the model for low-value areas of NSW was superior to that for high-value areas. NSW at the surface and TOA under all-sky conditions was significantly underestimated; the spatial distribution of the bias was negative in the north and positive in the south, bounded by 25°N for the annual and seasonal averaged difference maps. Compared with the all-sky condition, the simulation effect under clear-sky conditions was significantly better, which indicates that the cloud fraction is the key factor affecting the accuracy of the simulation. In particular, the bias of the TOA NSW under the clear-sky condition was <±10 W m-2 in the eastern areas. The performance of the model was better over the eastern monsoon region in winter and autumn for surface NSW under clear-sky conditions, which may be related to different levels of air pollution during each season. Among the 3 areas, the regional average biases overall were largest (negative) over the Qinghai-Tibet alpine region and smallest over the eastern monsoon region.

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