Projects
The AOD group has taken part to two European projects. The ECAWOM project of the
MAST (Marine Science and Technology) program and the STOWASUS-2100 project of
the Environment and Climate program. The goal of ECAWOM (1994-1996) (link 
descriptionpage} (European Coupled Atmosphere Ocean Model) has been the
development of a regional coupled atmosphere-ocean model. The STOWASUS-2100
(1997-2000)(link  descriptionpage) (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 (1997-98) (link  descriptionpage) and
IAMMed (1999)(link  descriptionpage). MAAMMed (Modelli Accoppiati Atmosfera
Mare nel Mediterraneo, Coupled Atmosphere Ocean Modeling in the Mediterranean sea)
has carried out the implementation of a meteo-marine prediction model in the
Mediterranean region. IAMMed (Interazione Atmosfera Mare nel Mediterraneo, Air-Sea
Interaction in the Mediterranean Sea) has analyzed the air-sea 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 (Air-Sea 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
(linkdescriptionpage), POM(linkdescriptionpage), WAM(linkdescriptionpage),
and MIAO (linkdescriptionpage).
HYPSE (Hydrostatic Padua Surface Elevation Model):.
HYPSE is a barotropic (2-dimensional) 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 C-grid, 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.
Figs:
Adr_hypse.gif
Caption: The curvilinear grid used for the operational implementation of HYPSE in the
Adriatic Sea
Hypse_moovie_icon  link to : Hypse_moovie.gif (actually an anigif)
Caption: 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
%missing M2.gif (left) K1.gif (right)
%missing Caption: The structure of the main semidiurnal tide M2 (left) and main diurnal
%missing tide (right) in the Adriatic Sea.
POM (Princeton Ocean Model): (link to home page and to manual POM_manual.pdf)
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
$\sigma$ coordinate, and a second order closure scheme for the computation of the
vertical mixing. The model adopts a C-grid with leap-frog 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 time-split 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 3-d 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_moovie.gif (anigif file) (missing… under development)
Caption The annual cycle of the water temperature along a section extending across the
Mediterranean Sea from the Gibraltar Strait (left) to the coast of Lebanon (right).
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 $f_{n+1} = 1.1 f_n$ .
Figs: wam_moovie_nov_icon.gifwam_moovie_nov.gif
Caption The evolution of the wave field in the Mediterranean Sea during November
2000.
Figs: wam_moovie_dic_icon.gifwam_moovie_dic.gif
Caption The evolution of the wave field in the Mediterranean Sea during December
2000.
BOLAM (Bologna Limited Area Model)
The BOLAM model has been developed at ISAC-CNR 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 water-species. 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 C-grid. Time discretization is based on a
two time-level scheme, with time split integration technique, forward for the horizontal
diffusion terms, pseudo-implicit for the vertical diffusion, forward-backward 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.
MIAO (Model of Interacting Atmosphere and Ocean), MIAO is a tri-modular model
(atmosphere+wave+ocean) of the coupled atmosphere-sea 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, grid-point model.
The POM model (Princeton Ocean Model, Blumberg A.F. and G.L.Mellor 1987) is a
hydrostatic, $\sigma$ coordinate, 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 air-sea 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 Monin-Obukhov theory, with an iterative solution on the
equation relating the dynamical quantities at the lowest level of the atmospheric model to
the Monin-Obukhov length and the SSR.
The model framework allows both one-way and two-way coupling. In a one-way coupled
simulation there is no feedback of the wave and SST fields on the atmospheric
circulation. The two-way coupling can be restricted to the wave feedback or to the SST
feedback, separately.
Miao is used for regional climate and hindcast studies.
(link Miao_moovie anigif
Caption: selection of fields computed by MIAO. The simulation covers the period 10th to
30th nov.1996. Top-panel: Sea Level Pressure and surface wind, bottom-left: Significant
wave height, bottom-right: sea surface elevation