scholarly journals Scale‐aware space‐time stochastic parameterization of subgrid‐scale velocity enhancement of sea surface fluxes

2021 ◽  
Author(s):  
Julie Bessac ◽  
Hannah M. Christensen ◽  
Kota Endo ◽  
Adam H. Monahan ◽  
Nils Weitzel
Keyword(s):  
Space Time ◽  
Surface Fluxes ◽  
Sea Surface ◽  
Subgrid Scale ◽  
Velocity Enhancement

scholarly journals Stochastic Parameterization of Subgrid-Scale Velocity Enhancement of Sea Surface Fluxes

2019 ◽  
Vol 147 (5) ◽  
pp. 1447-1469 ◽  
Author(s):  
Julie Bessac ◽  
Adam H. Monahan ◽  
Hannah M. Christensen ◽  
Nils Weitzel
Keyword(s):  
Climate Models ◽  
Model Simulation ◽  
Regional Analysis ◽  
Surface Flux ◽  
Atmospheric Model ◽  
Surface Fluxes ◽  
Sea Surface ◽  
Subgrid Scale ◽  
Flux Enhancement ◽  
Weather And Climate

Abstract Subgrid-scale (SGS) velocity variations result in gridscale sea surface flux enhancements that must be parameterized in weather and climate models. Traditional parameterizations are deterministic in that they assign a unique value of the SGS velocity flux enhancement to any given configuration of the resolved state. In this study, we assess the statistics of SGS velocity flux enhancement over a range of averaging scales (as a proxy for varying model resolution) through systematic coarse-graining of a convection-permitting atmospheric model simulation over the Indian Ocean and west Pacific warm pool. Conditioning the statistics of the SGS velocity flux enhancement on 1) the fluxes associated with the resolved winds and 2) the precipitation rate, we find that the lack of a separation between “resolved” and “unresolved” scales results in a distribution of flux enhancements for each configuration of the resolved state. That is, the SGS velocity flux enhancement should be represented stochastically rather than deterministically. The spatial and temporal statistics of the SGS velocity flux enhancement are investigated by using basic descriptive statistics and through a fit to an anisotropic space–time covariance structure. Potential spatial inhomogeneities of the statistics of the SGS velocity flux enhancement are investigated through regional analysis, although because of the relatively short duration of the simulation (9 days) distinguishing true inhomogeneity from sampling variability is difficult. Perspectives for the implementation of such a stochastic parameterization in weather and climate models are discussed.

A Deterministic Sea-Clutter Space–Time Model Based on Physical Sea Surface

2016 ◽  
Vol 54 (11) ◽  
pp. 6659-6673 ◽  
Author(s):  
Zhihui Xin ◽  
Guisheng Liao ◽  
Zhiwei Yang ◽  
Yuhong Zhang ◽  
Hongxing Dang
Keyword(s):  
Space Time ◽  
Sea Surface ◽  
Sea Clutter ◽  
Time Model ◽  
Model Based ◽  
Space Time Model

scholarly journals Multi-Physics Ensemble versus Atmosphere–Ocean Coupled Model Simulations for a Tropical-Like Cyclone in the Mediterranean Sea

Atmosphere ◽  
2019 ◽  
Vol 10 (4) ◽  
pp. 202 ◽  
Author(s):  
Antonio Ricchi ◽  
Mario Marcello Miglietta ◽  
Davide Bonaldo ◽  
Guido Cioni ◽  
Umberto Rizza ◽  
...  
Keyword(s):  
High Resolution ◽  
Mediterranean Sea ◽  
Computational Cost ◽  
Ocean Model ◽  
Surface Fluxes ◽  
Ocean Modeling ◽  
Sea Surface ◽  
Regional Ocean Modeling System ◽  
The Mediterranean ◽  
Physics Ensemble

Between 19 and 22 January 2014, a baroclinic wave moving eastward from the Atlantic Ocean generated a cut-off low over the Strait of Gibraltar and was responsible for the subsequent intensification of an extra-tropical cyclone. This system exhibited tropical-like features in the following stages of its life cycle and remained active for approximately 80 h, moving along the Mediterranean Sea from west to east, eventually reaching the Adriatic Sea. Two different modeling approaches, which are comparable in terms of computational cost, are analyzed here to represent the cyclone evolution. First, a multi-physics ensemble using different microphysics and turbulence parameterization schemes available in the WRF (weather research and forecasting) model is employed. Second, the COAWST (coupled ocean–atmosphere wave sediment transport modeling system) suite, including WRF as an atmospheric model, ROMS (regional ocean modeling system) as an ocean model, and SWAN (simulating waves in nearshore) as a wave model, is used. The advantage of using a coupled modeling system is evaluated taking into account air–sea interaction processes at growing levels of complexity. First, a high-resolution sea surface temperature (SST) field, updated every 6 h, is used to force a WRF model stand-alone atmospheric simulation. Later, a two-way atmosphere–ocean coupled configuration is employed using COAWST, where SST is updated using consistent sea surface fluxes in the atmospheric and ocean models. Results show that a 1D ocean model is able to reproduce the evolution of the cyclone rather well, given a high-resolution initial SST field produced by ROMS after a long spin-up time. Additionally, coupled simulations reproduce more accurate (less intense) sea surface heat fluxes and a cyclone track and intensity, compared with a multi-physics ensemble of standalone atmospheric simulations.

Assessment of the role of sea surface fluxes on eastern Mediterranean explosive cyclogenesis with the aid of the limited-area model COSMO.GR

2018 ◽  
Vol 208 ◽  
pp. 132-147 ◽  
Author(s):  
John Kouroutzoglou ◽  
Euripides N. Avgoustoglou ◽  
Helena A. Flocas ◽  
Maria Hatzaki ◽  
Panagiotis Skrimizeas ◽  
...  
Keyword(s):  
Eastern Mediterranean ◽  
Surface Fluxes ◽  
Sea Surface ◽  
Limited Area ◽  
Limited Area Model ◽  
Area Model
Sign in / Sign up

Export Citation Format

Share Document