Application of New Parameterizations for Atmospheric Boundary Layer and Oceanic Mixed Layer to Coupled Hurricane Modeling

2003 ◽  
Author(s):  
Shuyi S. Chen ◽  
William M. Frank ◽  
John C. Wyngaard
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Mixed Layer ◽  
Oceanic Mixed Layer

scholarly journals Application of an atmospheric boundary layer model to a large-scale coupled sea-ice-oceanic mixed-layer model for the Southern Ocean

1991 ◽  
Vol 15 ◽  
pp. 191-195 ◽  
Author(s):  
Achim Stössel
Keyword(s):  
Boundary Layer ◽  
Southern Ocean ◽  
Sea Ice ◽  
Atmospheric Boundary Layer ◽  
Mixed Layer ◽  
Layer Model ◽  
Oceanic Mixed Layer ◽  
Boundary Layer Model ◽  
Ice Model ◽  
Mixed Layer Model

A coupled sea-ice-oceanic mixed-layer model for the Southern Ocean is forced with daily atmospheric variables from the global analyses of the European Center for Medium Range Weather Forecasts (ECMWF). Using the analyses of the lowest level in the calculations of the turbulent heat fluxes and stresses with the appropriate bulk formulae, the simulation results resemble earlier ones with climatological forcing. In order to avoid a predetermination of the simulated sea-ice conditions from the (climatological) specification of the surface boundary conditions in the atmospheric general circulation model (AGCM), the sea-ice model is coupled additionally to a one-dimensional atmospheric boundary layer model. Using the global ECMWF-analyses as before, the coupled model is now forced from the geostrophic level (850 hPa). Without any changes of the original model parameters and physics, the results are rather poor in that the ice extent as well as the ice velocities are generally too low and that the ice thickness distribution resembles the results of a pure thermodynamic sea-ice model. The results with the forcing from the higher level are more realistic when snow and mixed-layer effects are neglected, thus resembling those of Koch (1988) in the Weddell Sea. This indicates that the parameterizations in the atmospheric boundary layer model have to be readjusted in order to interact realistically with the snow-sea-ice-oceanic mixed-layer model. Additionally, it will be demonstrated that the pattern of the wind field, whether from the geostrophic or the surface level, has a significant influence on the sea-ice model results.

scholarly journals Application of an atmospheric boundary layer model to a large-scale coupled sea-ice-oceanic mixed-layer model for the Southern Ocean

1991 ◽  
Vol 15 ◽  
pp. 191-195
Author(s):  
Achim Stössel
Keyword(s):  
Boundary Layer ◽  
Southern Ocean ◽  
Sea Ice ◽  
Atmospheric Boundary Layer ◽  
Mixed Layer ◽  
Layer Model ◽  
Oceanic Mixed Layer ◽  
Boundary Layer Model ◽  
Ice Model ◽  
Mixed Layer Model

A coupled sea-ice-oceanic mixed-layer model for the Southern Ocean is forced with daily atmospheric variables from the global analyses of the European Center for Medium Range Weather Forecasts (ECMWF). Using the analyses of the lowest level in the calculations of the turbulent heat fluxes and stresses with the appropriate bulk formulae, the simulation results resemble earlier ones with climatological forcing. In order to avoid a predetermination of the simulated sea-ice conditions from the (climatological) specification of the surface boundary conditions in the atmospheric general circulation model (AGCM), the sea-ice model is coupled additionally to a one-dimensional atmospheric boundary layer model. Using the global ECMWF-analyses as before, the coupled model is now forced from the geostrophic level (850 hPa). Without any changes of the original model parameters and physics, the results are rather poor in that the ice extent as well as the ice velocities are generally too low and that the ice thickness distribution resembles the results of a pure thermodynamic sea-ice model. The results with the forcing from the higher level are more realistic when snow and mixed-layer effects are neglected, thus resembling those of Koch (1988) in the Weddell Sea. This indicates that the parameterizations in the atmospheric boundary layer model have to be readjusted in order to interact realistically with the snow-sea-ice-oceanic mixed-layer model. Additionally, it will be demonstrated that the pattern of the wind field, whether from the geostrophic or the surface level, has a significant influence on the sea-ice model results.

scholarly journals An observational study of the evolution of the atmospheric boundary-layer over Cabo Frio, Brazil

2007 ◽  
Vol 25 (8) ◽  
pp. 1735-1744 ◽  
Author(s):  
S. H. Franchito ◽  
V. Brahmananda Rao ◽  
T. O. Oda ◽  
J. C. Conforte
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Mixed Layer ◽  
Coastal Upwelling ◽  
Vertical Mixing ◽  
Austral Summer ◽  
Sea Breeze ◽  
Austral Winter ◽  
Atmospheric Mixed Layer ◽  
Cabo Frio

Abstract. The effect of coastal upwelling on the evolution of the atmospheric boundary layer (ABL) in Cabo Frio (Brazil) is investigated. For this purpose, radiosounding data collected in two experiments made during the austral summer (upwelling case) and austral winter (no upwelling case) are analysed. The results show that during the austral summer, cold waters that crop up near the Cabo Frio coast favour the formation of an atmospheric stable layer, which persists during the upwelling episode. Due to the low SSTs, the descending branch of the sea-breeze circulation is located close to the coast, inhibiting the development of a mixed layer mainly during the day. At night, with the reduction of the land-sea thermal contrast the descending motion is weaker, allowing a vertical mixing. The stable ABL favours the formation of a low level jet, which may also contribute to the development of a nocturnal atmospheric mixed layer. During the austral winter, due to the higher SSTs observed near the coast, the ABL is less stable compared with that in the austral summer. Due to warming, a mixed layer is observed during the day. The observed vertical profiles of the zonal winds show that the easterlies at low levels are stronger in the austral summer, indicating that the upwelling modulates the sea-breeze signal, thus confirming model simulations.

scholarly journals Thermodynamic structure of the Atmospheric Boundary Layer over the Arabian Sea and the Indian Ocean during pre-INDOEX and INDOEX-FFP campaigns

2004 ◽  
Vol 22 (8) ◽  
pp. 2679-2691 ◽  
Author(s):  
M. V. Ramana ◽  
P. Krishnan ◽  
S. Muraleedharan Nair ◽  
P. K. Kunhikrishnan
Keyword(s):  
Boundary Layer ◽  
Indian Ocean ◽  
Atmospheric Boundary Layer ◽  
Mixed Layer ◽  
Arabian Sea ◽  
Trade Wind ◽  
Back Trajectory ◽  
Spatial And Temporal Variability ◽  
Air Mass ◽  
The Indian Ocean

Abstract. Spatial and temporal variability of the Marine Atmospheric Boundary Layer (MABL) height for the Indian Ocean Experiment (INDOEX) study period are examined using the data collected through Cross-chained LORAN (Long-Range Aid to Navigation) Atmospheric Sounding System (CLASS) launchings during the Northern Hemispheric winter monsoon period. This paper reports the results of the analyses of the data collected during the pre-INDOEX (1997) and the INDOEX-First Field Phase (FFP; 1998) in the latitude range 14°N to 20°S over the Arabian Sea and the Indian Ocean. Mixed layer heights are derived from thermodynamic profiles and they indicated the variability of heights ranging from 400m to 1100m during daytime depending upon the location. Mixed layer heights over the Indian Ocean are slightly higher during the INDOEX-FFP than the pre-INDOEX due to anomalous conditions prevailing during the INDOEX-FFP. The trade wind inversion height varied from 2.3km to 4.5km during the pre-INDOEX and from 0.4km to 2.5km during the INDOEX-FFP. Elevated plumes of polluted air (lofted aerosol plumes) above the marine boundary layer are observed from thermodynamic profiles of the lower troposphere during the INDOEX-FFP. These elevated plumes are examined using 5-day back trajectory analysis and show that one group of air mass travelled a long way from Saudi Arabia and Iran/Iraq through India before reaching the location of measurement, while the other air mass originates from India and the Bay of Bengal.

scholarly journals Atmospheric boundary layer dynamics from balloon soundings worldwide: CLASS4GL v1.0

2019 ◽  
Vol 12 (5) ◽  
pp. 2139-2153 ◽  
Author(s):  
Hendrik Wouters ◽  
Irina Y. Petrova ◽  
Chiel C. van Heerwaarden ◽  
Jordi Vilà-Guerau de Arellano ◽  
Adriaan J. Teuling ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Mixed Layer ◽  
Weather Prediction ◽  
Potential Temperature ◽  
Specific Humidity ◽  
Weather Extremes ◽  
Coupled Models ◽  
Layer Height ◽  
Mixed Layer Height

Abstract. The coupling between soil, vegetation and atmosphere is thought to be crucial in the development and intensification of weather extremes, especially meteorological droughts, heat waves and severe storms. Therefore, understanding the evolution of the atmospheric boundary layer (ABL) and the role of land–atmosphere feedbacks is necessary for earlier warnings, better climate projection and timely societal adaptation. However, this understanding is hampered by the difficulties of attributing cause–effect relationships from complex coupled models and the irregular space–time distribution of in situ observations of the land–atmosphere system. As such, there is a need for simple deterministic appraisals that systematically discriminate land–atmosphere interactions from observed weather phenomena over large domains and climatological time spans. Here, we present a new interactive data platform to study the behavior of the ABL and land–atmosphere interactions based on worldwide weather balloon soundings and an ABL model. This software tool – referred to as CLASS4GL (http://class4gl.eu, last access: 27 May 2018) – is developed with the objectives of (a) mining appropriate global observational data from ∼15 million weather balloon soundings since 1981 and combining them with satellite and reanalysis data and (b) constraining and initializing a numerical model of the daytime evolution of the ABL that serves as a tool to interpret these observations mechanistically and deterministically. As a result, it fully automizes extensive global model experiments to assess the effects of land and atmospheric conditions on the ABL evolution as observed in different climate regions around the world. The suitability of the set of observations, model formulations and global parameters employed by CLASS4GL is extensively validated. In most cases, the framework is able to realistically reproduce the observed daytime response of the mixed-layer height, potential temperature and specific humidity from the balloon soundings. In this extensive global validation exercise, a bias of 10.1 m h−1, −0.036 K h−1 and 0.06 g kg−1 h−1 is found for the morning-to-afternoon evolution of the mixed-layer height, potential temperature and specific humidity. The virtual tool is in continuous development and aims to foster a better process understanding of the drivers of the ABL evolution and their global distribution, particularly during the onset and amplification of weather extremes. Finally, it can also be used to scrutinize the representation of land–atmosphere feedbacks and ABL dynamics in Earth system models, numerical weather prediction models, atmospheric reanalysis and satellite retrievals, with the ultimate goal of improving local climate projections, providing earlier warning of extreme weather and fostering a more effective development of climate adaptation strategies. The tool can be easily downloaded via http://class4gl.eu (last access: 27 May 2018) and is open source.

Spatio-temporal variability of the thermodynamic characteristics of the marine atmospheric boundary layer (MABL) over the Indian and Southern Ocean (15oN to 70oS)

2021 ◽  
Author(s):  
Neha Salim ◽  
Harilal B Menon ◽  
Nadimpally V P Kiran Kumar
Keyword(s):  
Boundary Layer ◽  
Indian Ocean ◽  
Southern Ocean ◽  
Atmospheric Boundary Layer ◽  
Mixed Layer ◽  
Hadley Cell ◽  
Trade Wind ◽  
Marine Atmospheric Boundary Layer ◽  
Deep Mixed Layer ◽  
The Tropics

<p>The study deals with the thermodynamic characterization of marine atmospheric boundary layer (MABL) prevailing over regions of Indian Ocean and Indian Ocean sector of Southern Ocean from 29 high-resolution radiosondes launched during the International Indian Ocean Expedition (IIOE-2) and Southern Ocean Expedition (SOE-9). IIOE-2 was conducted during December 2015 onboard ORV Sagar Nidhi during which 11 radiosondes were launched, whereas SOE-9 was conducted during January-March 2017 onboard MV SA Agulhas which had 18 radiosonde ascents. These observations spanned latitudes from ~15<sup>o</sup>N to 70<sup>o</sup>S having crossed three major atmospheric circulation cells: Hadley cell, Ferrell cell and Polar cell. In addition, crucial atmospheric mesoscale phenomena such as inter-tropical convergence zone (ITCZ), sub-tropical jet (STJ) and polar jet (PJ) were encountered along with several oceanic fronts. Analysis of thermodynamic structure of MABL showed large variability in the formation of atmospheric sub-layers such as surface layer, mixed layer, cloud layer and trade wind inversion layer within MABL. MABL height varied spatially from tropics and mid-latitudes (12<sup>o</sup>N to 50<sup>o</sup>S) to polar latitudes (60<sup>o</sup>S to 68<sup>o</sup>S). Deep mixed layer were found over the tropics and mid-latitudes (~700 m) while shallow mixed layer was observed over the polar latitudes (~200 m). Deep mixed layer over the tropics were attributed to intense convective mixing while shallow mixed layer over polar regions was attributed to limited convective overturning associated with negative radiation balance at the surface. Convection was negligible over mid-latitudes (43<sup>o</sup>S to 55<sup>o</sup>S) where most of the atmospheric mixing were forced by frontal systems where lifting of air mass was mechanically driven by high speed winds rather than by convection. The enhanced convection over the tropics was confirmed from higher values of convective available potential energy (CAPE > 1000 J/kg) and large negative values of convective inhibition energy (CINE < -50 J/kg). Over the mid-latitude region (43<sup>o</sup>S to 50<sup>o</sup>S), enhanced advection and detrainment of convection was evident with maximum values of BRN shear (~65 knots) and lowest CAPE (~4 J/kg). Over polar latitudes (~60<sup>o</sup>S to 68<sup>o</sup>S), minimum CAPE (~17 J/kg) and low BRN shear (~5 knots) was noticed, which indicated presence of stable boundary layer conditions. A mesoscale phenomenon (i.e., ITCZ) was witnessed at ~5.92<sup>o</sup>S with highest CAPE ~2535.17 J/kg which signifies large convective instability resulting in strong convective updraft aiding thunderstorm activity and moderate precipitation over ITCZ. Analysis of conserved variables (CVA) revealed formation of second mixed layer (SML) structure between 12<sup>o</sup>N and 40<sup>o</sup>S. However, south of 40<sup>o</sup>S this structure ceases. The characteristics of SML structure and the plausible causes for its existence are also investigated.  </p>

scholarly journals Description and implementation of a MiXed Layer model (MXL, v1.0) for the dynamics of the atmospheric boundary layer in the Modular Earth Submodel System (MESSy)

2015 ◽  
Vol 8 (3) ◽  
pp. 453-471 ◽  
Author(s):  
R. H. H. Janssen ◽  
A. Pozzer
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Mixed Layer ◽  
Atmospheric Chemistry ◽  
Surface Fluxes ◽  
Sensitivity Analyses ◽  
Aerosol Formation ◽  
Convective Boundary ◽  
And Performance ◽  
Phase Chemistry

Abstract. We present a new submodel for the Modular Earth Submodel System (MESSy): the MiXed Layer (MXL) model for the diurnal dynamics of the convective boundary layer, including explicit representations of entrainment and surface fluxes. This submodel is embedded in a new MESSy base model (VERTICO), which represents a single atmospheric column. With the implementation of MXL in MESSy, MXL can be used in combination with other MESSy submodels that represent processes related to atmospheric chemistry. For instance, the coupling of MXL with more advanced modules for gas-phase chemistry (such as the Mainz Isoprene Mechanism 2 (MIM2)), emissions, dry deposition and organic aerosol formation than in previous versions of the MXL code is possible. Since MXL is now integrated in the MESSy framework, it can take advantage of future developments of this framework, such as the inclusion of new process submodels. The coupling of MXL with submodels that represent other processes relevant to chemistry in the atmospheric boundary layer (ABL) yields a computationally inexpensive tool that is ideally suited for the analysis of field data, for evaluating new parametrizations for 3-D models, and for performing systematic sensitivity analyses. A case study for the DOMINO campaign in southern Spain is shown to demonstrate the use and performance of MXL/MESSy in reproducing and analysing field observations.

Sign in / Sign up

Export Citation Format

Share Document