Coupled Atmosphere–Biophysics–Hydrology Models for Environmental Modeling

Walko, R. L.; Band, Lawrence E.; Kittel, T.G.F.; Lammers, R. B.; Lee, Tsengdar J.; Ojima, Dennis S.; Pielke, Roger A.; Taylor, Christopher M.; Tague, Christina; Tremback, Craig J.; Vidale, Pier Luigi

doi:10.1175/1520-0450(2000)039<0931:cabhmf>2.0.co;2

Cited by 522 publications

(430 citation statements)

References 48 publications

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“…The RAMS consists of non-hydrostatic, compressible dynamic equations, a thermodynamic equation and a set of equations representing the cloud microphysics. It estimates the three-dimensional spatial and temporal distribution of wind fields, temperature, mixing ratios and pressure in a terrain-following coordinate system using a two-way nested grid scheme [29][30][31]. RAMS input included European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis data, sea temperature, radiation, land-use and topographic data of the study area.…”

Section: (B) Atmospheric Modellingmentioning

confidence: 99%

Commuting fruit bats beneficially modulate their flight in relation to wind

et al. 2014

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When animals move, their tracks may be strongly influenced by the motion of air or water, and this may affect the speed, energetics and prospects of the journey. Flying organisms, such as bats, may thus benefit from modifying their flight in response to the wind vector. Yet, practical difficulties have so far limited the understanding of this response for free-ranging bats. We tracked nine straw-coloured fruit bats (Eidolon helvum) that flew 42.5 + 17.5 km (mean + s.d.) to and from their roost near Accra, Ghana. Following detailed atmospheric simulations, we found that bats compensated for wind drift, as predicted under constant winds, and decreased their airspeed in response to tailwind assistance such that their groundspeed remained nearly constant. In addition, bats increased their airspeed with increasing crosswind speed. Overall, bats modulated their airspeed in relation to wind speed at different wind directions in a manner predicted by a two-dimensional optimal movement model. We conclude that sophisticated behavioural mechanisms to minimize the cost of transport under various wind conditions have evolved in bats. The bats' response to the wind is similar to that reported for migratory birds and insects, suggesting convergent evolution of flight behaviours in volant organisms.

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Section: (B) Atmospheric Modellingmentioning

confidence: 99%

Commuting fruit bats beneficially modulate their flight in relation to wind

et al. 2014

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“…The spin-up time of the model for the generation of a realistic gravity-wave field is estimated to be less than three hours. RAMS uses a full package of parametrizations for representing cloud microphysics, convection (applied in grids 1-2), and radiation (see Gohm and Mayr (2005) between the surface and the atmosphere are computed by the prognostic sub-model LEAF-2 (Walko et al, 2000), using similarity theory following Louis et al (1982). Most relevant to the present study is the turbulence parametrization, which partly differs from that of Gohm and Mayr (2005).…”

Section: The Mesoscale Model Ramsmentioning

confidence: 99%

On the onset of bora and the formation of rotors and jumps near a mountain gap

Gohm

Mayr

Fix³

et al. 2008

Quart J Royal Meteoro Soc

125

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This study investigates the onset phase of a strong Adriatic bora windstorm that occurred on 4 April 2002. The target area is a gap about 20 km wide embedded in the coastal mountain barrier of the Dinaric Alps that favours strong jet-like winds. Airborne-aerosol back-scatter lidar measurements on board the DLR Falcon research aircraft, together with surface and upper-air observations, are used to verify high-resolution numerical experiments conducted with the mesoscale atmospheric model RAMS and a single-layer shallow-water model (SWM). Especially during the breakthrough phase of the bora, the flow at the gap exit exhibits a complex spatial structure and temporal evolution. On a transect through the centre of the gap, a hydraulic jump forms; this is located close to the coast throughout the night, and starts to propagate downstream in the early morning. On a transect through the edge of the gap, a lee-wave-induced rotor becomes established, due to boundary-layer separation. It starts to propagate downstream about two hours after the jump. This flow evolution implies that the onset of strong winds at the coast occurs several hours earlier downstream of the centre of the gap than downwind of the edge of the gap. Consequently, the wind field in the vicinity of Rijeka airport, located downwind of the gap, is strongly inhomogeneous and transient, and represents a potential hazard to aviation. Measured bora winds at the surface exceed 20 ms −1 , and the simulated wind speed in the gap wind layer exceeds 30 ms −1 . The simulated turbulent kinetic energy exceeds 10 m 2 s −2 .RAMS indicates that wave-breaking near a critical level is the dominant mechanism for the generation of the windstorm. Gap jets can be identified downstream of several mountain passes. The simulated wave pattern above the Dinaric Alps, the wave decay with height due to directional wind shear and the strong flow descent on the leeward side of the barrier are supported by measured back-scatter intensities. Basic bora flow features, including gap jets and jumps, are remarkably well reproduced by SWM simulations. The RAMS reference run captures observed flow phenomena and the temporal flow evolution qualitatively well. A cold low-level bias, an overestimated bora inversion strength, and a slightly too-early bora onset are probably related to insufficient turbulent mixing in the boundary layer. The amplitude of trapped gravity waves, the time of the bora breakthrough and the inversion strength are found to be quite sensitive to the turbulence parametrization.

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“…This convective scheme has been adopted based on previous studies performed within the area of study (Palau et al, 2005;Pérez-Landa et al, 2007). Finally, the LEAF-2 soilvegetation surface scheme was used to calculate sensible and latent heat fluxes exchanged with the atmosphere, using prognostic equations for soil moisture and temperature (Walko et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

Real-time weather forecasting in the Western Mediterranean Basin: An application of the RAMS model

Gómez

Caselles

Estrela

2014

Atmospheric Research

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Moreover, due to the physical complexity of the area of study, the model presents different degree of accuracy between coastal and inland stations. Precipitation has also been verified by means of yes/no contingency tables as well as scatter plots. These tables have been built using 4 specific thresholds that have permitted to compute some categorical statistics. From the results found, it is shown that the precipitation forecast in the area of study is in general over-predicted, but with marked differences between the seasons of the year. Finally, dividing the available data by season of the year, has permitted us to analyse differences in the observed patterns for the magnitudes mentioned above. These results have been used to better understand the behaviour of the RAMS model within the Valencia Region.

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Coupled Atmosphere–Biophysics–Hydrology Models for Environmental Modeling

Cited by 522 publications

References 48 publications

Commuting fruit bats beneficially modulate their flight in relation to wind

Commuting fruit bats beneficially modulate their flight in relation to wind

On the onset of bora and the formation of rotors and jumps near a mountain gap

Real-time weather forecasting in the Western Mediterranean Basin: An application of the RAMS model

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