scholarly journals A Coupled OpenFOAM-WRF Study on Atmosphere-Wake-Ocean Interaction

Fluids ◽  
2020 ◽  
Vol 6 (1) ◽  
pp. 12
Author(s):  
John Gilbert ◽  
Jonathan Pitt
Keyword(s):  
Field Data ◽  
Wrf Model ◽  
Coupled Model ◽  
Atmospheric Model ◽  
Ocean Model ◽  
Sea Surface ◽  
Small Scale ◽  
Surface Currents ◽  
Atmospheric Component ◽  
Surface Disturbances

This work aims to better understand how small scale disturbances that are generated at the air-sea interface propagate into the surrounding atmosphere under realistic environmental conditions. To that end, a one-way coupled atmosphere-ocean model is presented, in which predictions of sea surface currents and sea surface temperatures from a microscale ocean model are used as constant boundary conditions in a larger atmospheric model. The coupled model consists of an ocean component implemented while using the open source CFD software OpenFOAM, an atmospheric component solved using the Weather Research and Forecast (WRF) model, and a Python-based utility foamToWRF, which is responsible for mapping field data between the ocean and atmospheric domains. The results are presented for two demonstration cases, which indicate that the proposed coupled model is able to capture the propagation of small scale sea surface disturbances in the atmosphere, although a more thorough study is required in order to properly validate the model.

scholarly journals IMPROVEMENT OF STORM SURGE SIMULATION UPON PARAMETERIZATIONS OF COUPLED AIR-SEA INTERACTIONS

2012 ◽  
Vol 1 (33) ◽  
pp. 51
Author(s):  
Junichi Ninomiya ◽  
Nobuhito Mori ◽  
Tomohiro Yasuda ◽  
Hajime Mase ◽  
Naoto Kihara
Keyword(s):  
Energy Dissipation ◽  
Water Temperature ◽  
Field Data ◽  
Coupled Model ◽  
Wave Model ◽  
Atmospheric Model ◽  
Ocean Model ◽  
Ocean Current ◽  
Wave Energy Dissipation ◽  
Fully Coupled

Coupled atmosphere-ocean model has been developed in various organizations. Warner et al. developed fully coupled model, so-called COAWST, using the atmosphere model WRF, the ocean model ROMS and the wave model SWAN. Though there are several studies with coupled model, there is few research on tropical cyclone event analyzing the changes in ocean current and water temperature in detail. In this study, a series of numerical simulations was carried out targeting Typhoon Melor (2009), and it is analyzed against to the meteorologic and oceanic field data at Tanabe bay, Wakayama Prefecture in Japan. The results show that the wave energy dissipation by the wave model is effective in the change of ocean current and the thermal feedback by the atmospheric model is effective in the change of water temperature due to the typhoon passage.

scholarly journals Characteristics of convective snow bands along the Swedish east coast

2017 ◽  
Vol 8 (1) ◽  
pp. 163-175 ◽  
Author(s):  
Julia Jeworrek ◽  
Lichuan Wu ◽  
Christian Dieterich ◽  
Anna Rutgersson
Keyword(s):  
Regional Climate Model ◽  
East Coast ◽  
Climate Model ◽  
Regional Climate ◽  
Open Water ◽  
Atmospheric Model ◽  
Ocean Model ◽  
Sea Surface ◽  
Precipitation Rate ◽  
Shallow Convection

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.

scholarly journals Verification of the Reliability of Offshore Wind Resource Prediction Using an Atmosphere–Ocean Coupled Model

Energies ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 254
Author(s):  
Minhyeop Kang ◽  
Kyungnam Ko ◽  
Minyeong Kim
Keyword(s):  
Wind Speed ◽  
Energy Production ◽  
Prediction Models ◽  
Wrf Model ◽  
Coupled Model ◽  
Sea Surface ◽  
Offshore Wind ◽  
Wind Effect ◽  
Observation Data ◽  
Wind Resource

An atmosphere–ocean coupled model is proposed as an optimal numerical prediction method for the offshore wind resource. Meteorological prediction models are mainly used for wind speed prediction, with active studies using atmospheric models. Seawater mixing occurring at sea due to solar radiation and wind intensity can significantly change the sea surface temperature (SST), an important variable for predicting wind resources and energy production, considering its wind effect, within a short time. This study used the weather research forecasting and ocean mixed layer (WRF-OML) model, an atmosphere–ocean coupled model, to reflect time-dependent SST and sea surface fluxes. Results are compared with those of the WRF model, another atmospheric model, and verified through comparison with observation data of a meteorological mast (met-mast) at sea. At a height of 94 m, the wind speed predicted had a bias and root mean square error of 1.09 m/s and 2.88 m/s for the WRF model, and −0.07 m/s and 2.45 m/s for the WRF-OML model, respectively. Thus, the WRF-OML model has a higher reliability. In comparing to the met-mast observation data, the annual energy production (AEP) estimation based on the predicted wind speed showed an overestimation of 15.3% and underestimation of 5.9% from the WRF and WRF-OML models, respectively.

Optimizing COSMO_REA6 reanalysis radiation flux for a high resolution coastal ocean model

2020 ◽  
Author(s):  
Martin Vodopivec ◽  
Matjaž Ličer
Keyword(s):  
High Resolution ◽  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Atmospheric Model ◽  
Short Wave ◽  
Ocean Model ◽  
Sea Surface ◽  
Atmospheric Models ◽  
Fine Grid ◽  
Wave Flux

<p>When modelling coastal areas in high spatial resolution, it is also essential to obtain atmospheric forcing with suitably fine grid. The complex coastline and coastal orography exert strong influence on atmospheric fields, wind in particular, and the east Adriatic coast with numerous islands and coastal mountain ridges is a fine example. We decided to use a high resolution COSMO atmospheric reanalysis for our long term ROMS_AGRIF hindcasts, but in our initial experiments we found out that the atmospheric model significantly underestimates the short wave flux over the Mediterranean Sea, probably due to overestimation of high clouds formation and erroneous sea surface temperature used as a boundary condition. We explore different atmospheric models and different combinations of fluxes - direct, diffuse and clear sky solar radiation and combinations of fluxes from different atmospheric models (eg. ERA5). We compare them with solar irradiance observations at a coastal meteorological station and run year-long simulations to compare model sea surface temperature (SST) with satellite observations obtained from Coprenicus Marine Environment Monitoring Service.</p>

Impact of improved Ocean initial condition in Climate Forecast System (CFSv2) Hindcast run

2020 ◽  
Author(s):  
Samir Pokhrel ◽  
Hasibur Rahaman ◽  
Hemantkumar Chaudhari ◽  
Subodh Kumar Saha ◽  
Anupam Hazra
Keyword(s):  
Monsoon Rainfall ◽  
Ocean Model ◽  
Sea Surface ◽  
Sea Surface Salinity ◽  
Climate Forecast ◽  
Surface Currents ◽  
Forecast System ◽  
Surface Salinity ◽  
Climate Forecast System ◽  
The Indian Ocean

<p>IITM provides seasonal monsoon rainfall forecast using modified CGCM CFSv2. The present operational CFSv2 initilized with the INCOIS-GODAS ocean analysis based on MOM4p0d and 3DVar assimilation schemes. Recently new Ocean analysis GODAS-Mom4p1 using Moduler Ocean Model (MOM) upgraded physical model MOM4p1 is generated. This analysis has shown improvement in terms of subsurface temperature, salinity , current as well as sea surface temperature (SST), sea surface salinity (SSS) and surface currents over the Indian Ocean domain with respect to present operational INCOIS-GODAS analysis (Rahaman et al. 2017;Rahman et al. 2019). This newly generated ocean analysis is used to initialize NCEP Climate Forecast System (CFSv2) for the retrospective run from 2011 to 2018. The simulated coupled run has shown improvement in both oceanic as well atmospheric parameters. The more realistic nature of coupled simulations across the atmosphere and ocean may be promising to get better forecast skill.</p>

scholarly journals Dynamical Downscaling of SINTEX-F2v CGCM Seasonal Retrospective Austral Summer Forecasts over Australia

2017 ◽  
Vol 30 (9) ◽  
pp. 3219-3235 ◽  
Author(s):  
J. V. Ratnam ◽  
Takeshi Doi ◽  
Swadhin K. Behera
Keyword(s):  
Dynamical Downscaling ◽  
Wrf Model ◽  
Coupled Model ◽  
Austral Summer ◽  
Circulation Model ◽  
Summer Precipitation ◽  
Ocean Model ◽  
Global Circulation Model ◽  
Seasonal Forecasts ◽  
The Mean

An ensemble of 1-month-lead seasonal retrospective forecasts generated by the Scale Interaction Experiment (SINTEX)–Frontier Research Center for Global Change (FRCGC), version 2 tuned for performance on a vector supercomputer (SINTEX-F2v), coupled global circulation model (CGCM) were downscaled using the Weather Research and Forecasting (WRF) Model to improve the forecast of the austral summer precipitation and 2-m air temperatures over Australia. A set of four experiments was carried out with the WRF Model to improve the forecasts. The first was to drive the WRF Model with the SINTEX-F2v output, and the second was to bias correct the mean component of the SINTEX-F2v forecast and drive the WRF Model with the corrected fields. The other experiments were to use the SINTEX-F2v forecasts and the mean bias-corrected SINTEX-F2v forecasts to drive the WRF Model coupled to a simple mixed layer ocean model. Evaluation of the forecasts revealed the WRF Model driven by bias-corrected SINTEX-F2v forecasts to have a better spatial and temporal representation of forecast precipitation and 2-m air temperature, compared to SINTEX-F2v forecasts. Using a regional coupled model with the bias-corrected SINTEX-F2v forecast as the driver further improved the skill of the precipitation forecasts. The improvement in the WRF Model forecasts is due to better representation of the variables in the bias-corrected SINTEX-F2v forecasts driving the WRF Model. The study brings out the importance of including air–sea interactions and correcting the global forecasts for systematic biases before downscaling them for societal applications over Australia. These results are important for potentially improving austral summer seasonal forecasts over Australia.

Water Masses in the Pacific in CCSM3

2008 ◽  
Vol 21 (17) ◽  
pp. 4514-4528 ◽  
Author(s):  
Lu Anne Thompson ◽  
Wei Cheng
Keyword(s):  
North Pacific ◽  
Coupled Model ◽  
Ocean Model ◽  
Water Masses ◽  
Convergence Zone ◽  
Intermediate Water ◽  
Atmospheric Component ◽  
The North ◽  
Ocean Models ◽  
The North Pacific

Abstract An examination of model water masses in the North Pacific Ocean is performed in the Community Climate System version 3 (CCSM3) and its ocean-only counterpart. While the surface properties of the ocean are well represented in both simulations, biases in thermocline and intermediate-water masses exist that point to errors in both ocean model physics and the atmospheric component of the coupled model. The lack of North Pacific Intermediate Water (NPIW) in both simulations as well as the overexpression of a too-fresh Antarctic Intermediate Water (AAIW) is indicative of ocean model deficiencies. These properties reflect the difficulty of low-resolution ocean models to represent processes that control deep-water formation both in the Southern Ocean and in the Okhotsk Sea. In addition, as is typical of low-resolution ocean models, errors in the position of the Kuroshio, the North Pacific subtropical gyre western boundary current (WBC), impact the formation of the water masses that form the bulk of the thermocline as well as the properties of the NPIW. Biases that arise only in the coupled simulation include too-salty surface water in the subtropical North Pacific and too deep a thermocline, the source of which is the too-strong westerlies at midlatitudes. Biases in the location of the intertropical convergence zone (ITCZ) and the southern Pacific convergence zone (SPCZ) lead to the opposite hemispheric asymmetry in water mass structure when compared to observations. The atmospheric component of the coupled model acts to compound most ocean model biases.

Interdecadal Change in Properties of El Niño–Southern Oscillation in an Intermediate Coupled Model

2005 ◽  
Vol 18 (9) ◽  
pp. 1369-1380 ◽  
Author(s):  
Rong-Hua Zhang ◽  
Antonio J. Busalacchi
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Coupled Model ◽  
Ocean Model ◽  
Sea Surface ◽  
Subsurface Temperature ◽  
Intermediate Coupled Model

Abstract The role of subsurface temperature variability in modulating El Niño–Southern Oscillation (ENSO) properties is examined using an intermediate coupled model (ICM), consisting of an intermediate dynamic ocean model and a sea surface temperature (SST) anomaly model. An empirical procedure is used to parameterize the temperature of subsurface water entrained into the mixed layer (Te) from sea level (SL) anomalies via a singular value decomposition (SVD) analysis for use in simulating sea surface temperature anomalies (SSTAs). The ocean model is coupled to a statistical atmospheric model that estimates wind stress anomalies also from an SVD analysis. Using the empirical Te models constructed from two subperiods, 1963–79 (T63–79e) and 1980–96 (T80–96e), the coupled system exhibits strikingly different properties of interannual variability (the oscillation period, spatial structure, and temporal evolution). For the T63–79e model, the system features a 2-yr oscillation and westward propagation of SSTAs on the equator, while for the T80–96e model, it is characterized by a 5-yr oscillation and eastward propagation. These changes in ENSO properties are consistent with the behavior shift of El Niño observed in the late 1970s. Heat budget analyses further demonstrate a controlling role played by the vertical advection of subsurface temperature anomalies in determining the ENSO properties.

scholarly journals Development of a MetUM (v 11.1) and NEMO (v 3.6) coupled operational forecast model for the Maritime Continent – Part 1: Evaluation of ocean forecasts

2021 ◽  
Vol 14 (2) ◽  
pp. 1081-1100
Author(s):  
Bijoy Thompson ◽  
Claudio Sanchez ◽  
Boon Chong Peter Heng ◽  
Rajesh Kumar ◽  
Jianyu Liu ◽  
...  
Keyword(s):  
Coupled Model ◽  
Forecast Model ◽  
Horizontal Resolution ◽  
Ocean Model ◽  
Sea Surface ◽  
Maritime Continent ◽  
Acceptable Error ◽  
Operational Forecast ◽  
In Situ Observations

Abstract. This article describes the development and ocean forecast evaluation of an atmosphere–ocean coupled prediction system for the Maritime Continent (MC) domain, which includes the eastern Indian and western Pacific oceans. The coupled system comprises regional configurations of the atmospheric model MetUM and ocean model NEMO at a uniform horizontal resolution of 4.5 km × 4.5 km, coupled using the OASIS3-MCT libraries. The coupled model is run as a pre-operational forecast system from 1 to 31 October 2019. Hindcast simulations performed for the period 1 January 2014 to 30 September 2019, using the stand-alone ocean configuration, provided the initial condition to the coupled ocean model. This paper details the evaluations of ocean-only model hindcast and 6 d coupled ocean forecast simulations. Direct comparison of sea surface temperature (SST) and sea surface height (SSH) with analysis, as well as in situ observations, is performed for the ocean-only hindcast evaluation. For the evaluation of coupled ocean model, comparisons of ocean forecast for different forecast lead times with SST analysis and in situ observations of SSH, temperature, and salinity have been performed. Overall, the model forecast deviation of SST, SSH, and subsurface temperature and salinity fields relative to observation is within acceptable error limits of operational forecast models. Typical runtimes of the daily forecast simulations are found to be suitable for the operational forecast applications.

scholarly journals Modelling the mid-Pliocene Warm Period climate with the IPSL coupled model and its atmospheric component LMDZ5A

2012 ◽  
Vol 5 (3) ◽  
pp. 903-917 ◽  
Author(s):  
C. Contoux ◽  
G. Ramstein ◽  
A. Jost
Keyword(s):  
Boundary Conditions ◽  
Coupled Model ◽  
Atmospheric Model ◽  
Warm Period ◽  
Full Description ◽  
Model Intercomparison ◽  
Atmospheric Component ◽  
Model Experiments ◽  
Simulated Precipitation ◽  
Intercomparison Project

Abstract. This paper describes the experimental design and model results of the climate simulations of the mid-Pliocene Warm Period (mPWP, ca. 3.3–3 Ma) using the Institut Pierre Simon Laplace model (IPSLCM5A), in the framework of the Pliocene Model Intercomparison Project (PlioMIP). We use the IPSL atmosphere ocean general circulation model (AOGCM), and its atmospheric component alone (AGCM), to simulate the climate of the mPWP. Boundary conditions such as sea surface temperatures (SSTs), topography, ice-sheet extent and vegetation are derived from the ones imposed by the Pliocene Model Intercomparison Project (PlioMIP), described in Haywood et al. (2010, 2011). We first describe the IPSL model main features, and then give a full description of the boundary conditions used for atmospheric model and coupled model experiments. The climatic outputs of the mPWP simulations are detailed and compared to the corresponding control simulations. The simulated warming relative to the control simulation is 1.94 °C in the atmospheric and 2.07 °C in the coupled model experiments. In both experiments, warming is larger at high latitudes. Mechanisms governing the simulated precipitation patterns are different in the coupled model than in the atmospheric model alone, because of the reduced gradients in imposed SSTs, which impacts the Hadley and Walker circulations. In addition, a sensitivity test to the change of land-sea mask in the atmospheric model, representing a sea-level change from present-day to 25 m higher during the mid-Pliocene, is described. We find that surface temperature differences can be large (several degrees Celsius) but are restricted to the areas that were changed from ocean to land or vice versa. In terms of precipitation, impact on polar regions is minor although the change in land-sea mask is significant in these areas.

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