
Projects
The AOD group has taken part to two European projects. The ECAWOM
project of the MAST (Marine Science and Technology) program and
the STOWASUS2100 project of the Environment
and Climate program. The goal of ECAWOM
(19941996) (European Coupled
Atmosphere Ocean
Model) has been the development
of a regional coupled atmosphereocean model. The STOWASUS2100
(19972000) (STOrms, WAves,
SUrges Scenarios)
has analyzed the effects of the doubled concentration of greenhouse
gases on storms, ocean waves and coastal surges in the European
Seas.
The AOD group has coordinated two Italian projects, both supported
by CNR (Consiglio Nazionale delle Ricerche), MAAMMed (199798)
and IAMMed (1999). MAAMMed
(Modelli Accoppiati
Atmosfera Mare
nel Mediterraneo, Coupled
Atmosphere Ocean Modeling in the Mediterranean sea) has carried
out the implementation of a meteomarine prediction model in the
Mediterranean region. IAMMed
(Interazione Atmosfera
Mare nel Mediterraneo,
AirSea Interaction in the Mediterranean Sea) has analyzed the
airsea fluxes derived from satellite observations and computed
by model simulations and intercompared these two different fields.
Presently, the AOD group is taking part to two Italian Projects.
The "Programma Ambiente Mediterraneo" (Mediterranean
Environment Program) supported by MURST (Italian Ministry for
the University and Scientific and Technologic Research) and coordinated
by ENEA. The ASIMed project (AirSea Interaction in the Mediterranean
Sea) supported by ASI (Italian Space Agency).
The AOD group acts as consultant for Italian agencies and companies:
Particularly, a deterministic system for the prediction of the
storm surge in the Northern Adriatic is being implemented for
the town council of Venice.
The modeling activity of the AOD group is based on a set of models:
HYPSE (moovie),
POM (moovie),
WAM (moovie),
and MIAO (moovie).
(click on acronym for the description of the model and view the
animation of the model results).
HYPSE (Hydrostatic Padua Surface Elevation Model):
HYPSE is a barotropic (2dimensional) model in curvilinear coordinates,
whose numeric is similar to the external mode of the well known
POM coastal model, but it includes the sea level pressure and
the astronomical tide forcing. The model uses a Arakawa Cgrid,
a leap frog time differencing scheme, but for the diffusion terms
that is integrated using a forward scheme. A standard quadratic
bottom friction term is adopted. HYPSE predicts the sea surface
elevation resulting from the divergence of the horizontal transport.
It is used for the simulation of the storm surge in the Adriatic
Sea. The adjoint of HYPSE is presently been developed and it will
be used for data assimilation studies.
The curvilinear grid used for the operational implementation
of HYPSE in the Adriatic Sea.
The meteorological contribution to the surface elevation
of the Adriatic Sea from 10th to 30th November 1996 computed
by HYPSE using the wind and sea level pressure fields of ECMWF
(click here
or on the image to see the moovie).
The structure of the main semidiurnal tide M2 (left) and
main diurnal tide (right) in the Adriatic Sea.
POM (Princeton Ocean Model):
The original POM model has been developed at Princeton University(
Blumberg A.F. and G.L.Mellor 1987). POM is an ocean circulation
model, which solves the hydrostatic primitive equations, with
a free surface, curvilinear horizontal coordinates, vertical sigmacoordinate,
and a second order closure scheme for the computation of the vertical
mixing. The model adopts a Cgrid with leapfrog time differencing,
but for the diffusion terms which are integrated using a forward
scheme. The integration of the vertical diffusion is fully implicit.
The equations are integrated with a timesplit scheme, where the
barotropic circulation (external mode) is integrated with a time
step more than one order of magnitude smaller than the baroclinic
component (internal mode). The version of POM used by the AOD
group uses has been extensively rewritten and modular version
of the model developed at Princeton, which, however does not modify
the basic dynamics of the model.. The model describes the 3d
structure of the ocean circulation and of the temperature and
salinity fields. It is used by the AOD group mainly for simulation
of the circulation in the Adriatic and Mediterranean Sea.
POM
Manual (pdf format)
POM
Home Page
WAM (WAve Model):
The WAM wave model (WAMDI group, 1987) solves the energy transfer
equation for the wave spectrum. The equation describes the variation
of the wave spectrum F in space and time due to the advection
of energy and local interactions. The wave spectrum is locally
modified by the input of energy from the wind, the redistribution
of energy due to nonlinear interactions and energy dissipation
due to wave breaking. These processes are represented by the source
functions S_{in} , S_{nl}, and S_{ds}
respectively. The energy propagation and the integration of the
source function are treated numerically using different techniques.
The advective term is integrated with a first order upwind scheme.
The source function is integrated with an implicit. scheme that
allows an integration time step greater than the dynamic adjustment
time of the highest frequencies in the model prognostic range.
AOD uses a fortran90 version of WAM, developed by G.Giuliani.
In the standard implementazion, the wave spectrum is discretized
using 12 directions and 25 frequencies extending from 0.041 to
0.42 Hz with a logarithmic increment f_{n+1} = 1.1 f_{n}.
The evolution of the wave field in the Mediterranean
Sea during November 2000 (click here
or on the image to view the moovie).
The evolution of the wave field in the Mediterranean Sea
during December 2000 (click here
or on the image to view the moovie).
Links about WAM:
http://www.dkrz.de/forschung/reports/report4/wamh1.html
http://www.ecmwf.int/research/ifsdocs/WAVES/Chap6_Software2.html
http://www.fnmoc.navy.mil/PUBLIC/WAM/wam_det.html
http://www.cineca.it/meteo/index2.html
http://atmoweb.pstabruzzo.it/wam/
BOLAM (Bologna Limited Area Model)
The BOLAM model has been developed at ISACCNR of Bologna (Buzzi
et al, 1994). It is a grid point, hydrostatic model in sigma coordinates,
computing zonal and meridional wind components $u,v$, potential
temperature theta, specific humidity h and surface
pressure p_{s}. The physics of the model includes:
parameterization of vertical diffusion in the planetary boundary
layer depending on the Richardson number, dry adiabatic adjustment,
soil water and energy balance (the sea surface temperature is
prescribed), radiation, cloud effects, large scale precipitation,
condensation, evaporation, moist convection, and a mycrophysics
scheme with 5 waterspecies. A fourth order horizontal diffusion
is added to the prognostic equations except in the tendency of
surface pressure, while second order horizontal diffusion is applied
to the divergence of the horizontal velocity. Vertical discretization
is of the Lorentz type (vertical velocity is defined at intermediate
levels between the levels of the prognostic variables) with a
variable step which gives higher resolution near the surface and
the tropopause. Horizontal discretization adopts the Arakawa Cgrid.
Time discretization is based on a two timelevel scheme, with
time split integration technique, forward for the horizontal diffusion
terms, pseudoimplicit for the vertical diffusion, forwardbackward
for the gravity wave motion and advection terms.
A parallel version for QUADRICS has been developed in cooperation
with ENEA and is used for operational prediction by Servizi Tecnici
Nazionali (link). It also used for operational predictions by
Servizio Agrometeo Regionale Sardegna (link), Centro Meteoidrologico
della regione Liguria (link), Natioanal Observatory of Athens(link).
BOLAM has been extensively used during the MAP (link) campaign
and in the series of intercomparison studies COMPARE I, II, III
sponsored by WMO.
Links about BOLAM
http://www.cmirl.ge.infn.it/MAP/BOLAM/Bolamin.htm
http://www.cineca.it/editions/ssc97/html/tartagli.htm
http://www.map.ethz
http://www.isao.bo.cnr.it/~dinamica/MAP.html
MIAO (Model of Interacting Atmosphere and Ocean):
MIAO is a trimodular model (atmosphere+wave+ocean) of the coupled
atmospheresea system (called MIAO, Model of Interacting Atmosphere
and Ocean). The model structure consists of three modules:BOLAM,
POM, and WAM. The BOLAM model (BOlogna Limited Area Model, Buzzi
et al. 1993) is a complete meteorological, hydrostatic, gridpoint
model. The POM model (Princeton Ocean Model, Blumberg A.F. and
G.L.Mellor 1987) is a hydrostatic, sigmacoordinate, ocean
circulation model, which adopts a second order closure scheme
for the computation of the vertical mixing. The WAM (WAve Model,
The WAMDI Group 1988) model describes the evolution of the ocean
wave spectrum.
The MIAO model computes the airsea fluxes, accounting for the
feedbacks of the sea on the atmosphere. In this coupled model
the sea surface temperature computed by the ocean circulation
component and the sea surface roughness computed by ocean wave
component are used by atmospheric circulation component which,
in turn, computes the surface fluxes of momentum, heat and moisture.
The representation of the boundary layer in MIAO is based on the
MoninObukhov theory, with an iterative solution on the equation
relating the dynamical quantities at the lowest level of the atmospheric
model to the MoninObukhov length and the SSR.
The model framework allows both oneway and twoway coupling.
In a oneway coupled simulation there is no feedback of the wave
and SST fields on the atmospheric circulation. The twoway coupling
can be restricted to the wave feedback or to the SST feedback,
separately.
Miao is used for regional climate and hindcast studies.
Click here
to see a selection of fields computed by MIAO. The simulation
covers the period 10th to 30th nov.1996. Toppanel: Sea Level
Pressure and surface wind, bottomleft: Significant wave height,
bottomright: sea surface elevation.

