An Alternative Approach to Nonhydrostatic Modeling

Janjić, Zavisă; Gerrity, Joseph P.; Ničković, Slobodan

doi:10.1175/1520-0493(2001)129<1164:aaatnm>2.0.co;2

Cited by 249 publications

(139 citation statements)

References 12 publications

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“…3.3. Janjic, 2004;Janjic and Black, 2007;Janjic et al, 2011) is a unified atmospheric model developed at the National Centers for Environmental Prediction (NCEP) (Janjic et al, 2001;Janjic, 2003). A powerful element of the model constitutes its nonhydrostatic dynamical core, activated depending on the resolution, providing the capability to be used for applications spanning at a wide range of temporal (from short-to longterm) and spatial (from regional to global) scales.…”

Section: Model Descriptionmentioning

confidence: 99%

“…An additional dynamic feature of the NMMB is the consideration of various parameterization schemes which can be incorporated into the numerical simulations. In our experiments, the parameterization schemes of Betts-Miller-Janjic (Betts, 1986;Betts and Miller, 1986;Janjic, 1994Janjic, , 2000, Ferrier (Ferrier et al, 2002), Mellor-Yamada-Janjic (Janjic et al, 2001) and Monin-Obukhov (Monin and Obukhov, 1954) have been utilized for the convection, cloud microphysics, turbulence and surface layer, respectively, as well as the NOAH land model (Ek et al, 2003). Moreover, only the greenhouse gases are taken into account and not the emitted short lived atmospheric gases.…”

Section: Model Descriptionmentioning

confidence: 99%

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Direct radiative effects during intense Mediterranean desert dust outbreaks

et al. 2018

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Abstract. The direct radiative effect (DRE) during 20 intense and widespread dust outbreaks, which affected the broader Mediterranean basin over the period March 2000-February 2013, has been calculated with the NMMB-MONARCH model at regional (Sahara and European continent) and shortterm temporal (84 h) scales. According to model simulations, the maximum dust aerosol optical depths (AODs) range from ∼ 2.5 to ∼ 5.5 among the identified cases. At midday, dust outbreaks locally induce a NET (shortwave plus longwave) strong atmospheric warming (DRE ATM values up to 285 W m −2 ; Niger-Chad; dust AODs up to ∼ 5.5) and a strong surface cooling (DRE NETSURF values down to −337 W m −2 ), whereas they strongly reduce the downward radiation at the ground level (DRE SURF values down to −589 W m −2 over the Eastern Mediterranean, for extremely high dust AODs, 4.5-5). During night-time, reverse effects of smaller magnitude are found. At the top of the atmosphere (TOA), positive (planetary warming) DREs up to 85 W m −2 are found over highly reflective surfaces (Niger-Chad; dust AODs up to ∼ 5.5) while negative (planetary cooling) DREs down to −184 W m −2 (Eastern Mediterranean; dust AODs 4.5-5) are computed over dark surfaces at noon. Dust outbreaks significantly affect the mean regional radiation budget, with NET DREs ranging from −8.5 to 0.5 W m −2 , from −31.6 to 2.1 W m −2 , from −22.2 to 2.2 W m −2 and from −1.7 to 20.4 W m −2 for TOA, SURF, NETSURF and ATM, respectively. Although the shortwave DREs are larger than the longwave ones, the latter are comparable or even larger at TOA, particularly over the Sahara at midday. As a response to the strong surface day-time cooling, dust outbreaks cause a reduction in the regional sensible and latent heat fluxes by up to 45 and 4 W m −2 , respectively, averaged over land areas of the simulation domain. Dust outbreaks reduce the temperature at 2 m by up to 4 K during day-time, whereas a reverse tendency of similar magnitude is found during nighttime. Depending on the vertical distribution of dust loads and time, mineral particles heat (cool) the atmosphere by up to 0.9 K (0.8 K) during day-time (night-time) within atmospheric dust layers. Beneath and above the dust clouds, mineral particles cool (warm) the atmosphere by up to 1.3 K (1.2 K) at noon (night-time). On a regional mean basis, negative feedbacks on the total emitted dust (reduced by 19.5 %) and dust AOD (reduced by 6.9 %) are found when dust interacts with the radiation. Through the consideration of dust radiative effects in numerical simulations, the model positive and negative biases for the downward surface SW or LW radiation, respectively, with respect to Baseline Surface Radiation Network (BSRN) measurements, are reduced. In addition, they also reduce the model near-surface (at 2 m) nocturnal cold biases by up to 0.5 K (regional averages), as well as the model warm biases at 950 and 700 hPa, where the dust concentration is maximized, by up to 0.4 K. However, improvements are relatively small and do not happen in all ...

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Section: Model Descriptionmentioning

confidence: 99%

Section: Model Descriptionmentioning

confidence: 99%

Direct radiative effects during intense Mediterranean desert dust outbreaks

et al. 2018

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“…The model employed 30 layers vertically, with the lowest computational layer being approximately 18 m above ground level and the top at 50 hPa. The initial guess field and lateral boundary values for the outermost domain were compiled from the North American Model (NAM) [27]. Four-dimensional data assimilation was conducted using vertical soundings and surface measurements.…”

Section: Model Descriptionsmentioning

confidence: 99%

A Conservative Downscaling of Satellite-Detected Chemical Compositions: NO2 Column Densities of OMI, GOME-2, and CMAQ

et al. 2018

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A conservative downscaling technique was applied when comparing nitrogen dioxide (NO 2 ) column densities from space-borne observations and a fine-scale regional model. The conservative downscaling was designed to enhance the spatial resolution of satellite measurements by applying the fine-scale spatial structure from the model, with strict mass conservation at each satellite footprint pixel level. With the downscaling approach, NO 2 column densities from the Ozone Monitoring Instrument (OMI; 13 × 24 km nadir footprint resolution) and the Global Ozone Monitoring Experiment-2 (GOME-2; 40 × 80 km) show excellent agreement with the Community Multiscale Air Quality (CMAQ; 4 × 4 km) NO 2 column densities, with R = 0.96 for OMI and R = 0.97 for GOME-2. We further introduce an approach to reconstruct surface NO 2 concentrations by combining satellite column densities and simulated surface-to-column ratios from the model. Compared with the Environmental Protection Agency's (EPA) Air Quality System (AQS) surface observations, the reconstructed surface concentrations show a good agreement; R = 0.86 for both OMI and GOME-2. This study demonstrates that the conservative downscaling approach is a useful tool to compare coarse-scale satellites with fine-scale models or observations in urban areas for air quality and emissions studies. The reconstructed fine-scale surface concentration field could be used for future epidemiology and urbanization studies.

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“…The atmospheric component is based on the Workstation Eta non-hydrostatic limited area model (Papadopoulos et al, 2002;Janjic, 2001;Nickovic et al, 2001;Mesinger et al, 1988). The ocean wave component is based on the fourth generation OpenMP (OMP) version of the WAM model (Monbaliu et al, 2000;Korres et al, 2011) and the resulting name of the coupled system is WEW.…”

Section: Overview Of Modeling Components Of the Coupled Systemmentioning

confidence: 99%

A fully coupled atmosphere–ocean wave modeling system for the Mediterranean Sea: interactions and sensitivity to the resolved scales and mechanisms

et al. 2016

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Abstract. It is commonly accepted that there is a need for a better understanding of the factors that contribute to air-sea interactions and their feedbacks. In this context it is important to develop advanced numerical prediction systems that treat the atmosphere and the ocean as a unified system. The realistic description and understanding of the exchange processes near the ocean surface requires knowledge of the sea state and its evolution. This can be achieved by considering the sea surface and the atmosphere as a continuously crosstalking dynamic system. Following and adapting concepts already developed and implemented in large-scale numerical weather models and in hurricane simulations, this study aims to present the effort towards developing a new, highresolution, two-way fully coupled atmosphere-ocean wave model in order to support both operational and research activities. A specific issue that is emphasized is the determination and parameterization of the air-sea momentum fluxes in conditions of extremely high and time-varying winds. Software considerations, data exchange as well as computational and scientific performance of the coupled system, the so-called WEW (worketa-wam), are also discussed. In a case study of a high-impact weather and sea-state event, the wind-wave parameterization scheme reduces the resulted wind speed and the significant wave height as a response to the increased aerodynamic drag over rough sea surfaces. Overall, WEW offers a more realistic representation of the momentum exchanges in the ocean wind-wave system and includes the effects of the resolved wave spectrum on the drag coefficient and its feedback on the momentum flux.

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An Alternative Approach to Nonhydrostatic Modeling

Cited by 249 publications

References 12 publications

Direct radiative effects during intense Mediterranean desert dust outbreaks

Direct radiative effects during intense Mediterranean desert dust outbreaks

A Conservative Downscaling of Satellite-Detected Chemical Compositions: NO2 Column Densities of OMI, GOME-2, and CMAQ

A fully coupled atmosphere–ocean wave modeling system for the Mediterranean Sea: interactions and sensitivity to the resolved scales and mechanisms

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