tridimensional compressible non hydrostatic resolution 1km navier-stokes equations
DESCRIPTION
ARPS( Advanced Regional Prediction System ) Version 4.5.1. Center for Analysis and Prediction of Storms (CAPS), Oklahoma University. tridimensional compressible non hydrostatic resolution 1km Navier-Stokes equations Generalized coordinate system - PowerPoint PPT PresentationTRANSCRIPT
ARPS(Advanced Regional Prediction System )Version 4.5.1.
Center for Analysis and Prediction of Storms (CAPS), Oklahoma University
•tridimensional• compressible • non hydrostatic• resolution 1km •Navier-Stokes equations• Generalized coordinate systemParameterized microphysics (Kessler and Lin)
Main Equations
•Prognostic equations for u, v, w,, p’ and Where: : water vapor, cloud water , rain water, cloud ice, snow and hail (graupel)•Equation of state
SqGDqGqV
qW
qv
quq
t
q
c
))(
(
)(
*
*
****
Conservation equations for mixing ratios (vapor qv,
cloud water qc , rain water qr, cloud ice qi, snow qs
and hail qh.)advection
sedimentation mixing
Sources (microphysical processes)
General simulation parameters.
• Domain: 90x96x20 km • Horizontal Resolution : 1 km• Vertical Resolution : 0.5 km • Time Resolution: 6 s• Lateral Boundary Conditions: Open (Klemp and
Wilhemson, 1978) • Top and Bottom B.C. Zero normal gradient• Considered:
Orography, Radiative effects, Land Use, Coriolis.
July 2, 2001 Severe storm
Convection initiated with an ellipsoidal perturbation
Θmax= 4KCentral coordinates: x=50 km, y=37 km, z=1.5 kmDimensions: 10x30x1.5 km (Simulating the form and
dimensions of a preexisting storm)
•Control output : every 60 s
•Total simulation time: 3 h
t = 30 min., t = 50 min., t = 70 minVertical Vorticity (x 10-5 s-1), z = 6 km
w(m/s)
Vertical Vorticity, z = 9 km
qc and qR (g/kg) for the Wmax. slice in the Y-Z plane
qi and qH (g/kg) for for the Wmax. slice in the Y-Z plane
qc and qR (g/kg) for theWmax. slice in the Y-Z plane
qi and qH (g/kg) for theWmax. slice in the Y-Z plane
Trajectories of the centers of both cells and the center of the system. Point labels indicate simulation time.
Left moving cell
Center of the system
Right moving cell
Left moving cell
Center of the system
Right moving cell
CONCLUSIONS• Low precipitations supercell system, generated in
an environment of high instability, and clockwise turning hodograph with low wind speeds at the lower levels and strong, and nearly unidirectional wind shear at heights from 6 to 12 km.
• Split storm structure, more clear at upper levels• Left moving cell disspated by the entrainment of
cold air, generated in the central downdraft at low and middle levels, conditioned by the wind profile.