source: TI01-discovery/trunk/schema/numsim/NMM/higem/HiGEM_HADGEM_6.1_control.xml @ 1214

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Revision 1214, 27.8 KB checked in by hearnsha, 15 years ago (diff)

Completed Sea Ice description for Higem NumSim

1<?xml version="1.0" encoding="UTF-8"?>
2<NS_Simulated xmlns:xsi=""
3    xmlns:xlink="" xsi:noNamespaceSchemaLocation="../../NumSim.xsd">
4    <!-- Note that this is a handcoded example XML file which should not be regarded as
5        authoratative about the Higem control run, Charlotte Pascoe, May 2006 -->
6    <NS_CodeBase>
7        <NS_Description>This is the HiGEM codebase</NS_Description>
8        <NS_Model>
9            <NS_Name>HiGEM V6.1 Control (xbpjt)</NS_Name>
10            <NS_Category>GCM</NS_Category>
11            <NS_RelatedModel
12                xlink:href=""
13                xlink:title="HiGEM">
14                <NS_Relationship>This is the first HiGEM climate run </NS_Relationship>
15            </NS_RelatedModel>
16            <NS_References>
17                <NS_Reference></NS_Reference>
18            </NS_References>
19            <NS_Component><!-- ATMOSPHERE -->
20                <NS_Name>Atmosphere</NS_Name>
21                <NS_ComponentType>Atmosphere</NS_ComponentType>
22                <NS_Description><!-- SPACE AND TIME -->
23                    The atmospheric component of HiGEM has 38 vertical levels
24                    with a horizontal resolution of 1.25 degrees of latitude by 0.83 degrees of longitude,
25                    which produces a global grid of 288 x 217 grid cells. This is equivalent to a surface
26                    resolution of about 139 km x 92 km at the Equator, reducing to 98 km x 92 km
27                    at 45 degrees of latitude (comparable to a spectral resolution of Nblah).
28                    The atmospheric timestep period is 20 minutes (72 timesteps per 1 days).
29                </NS_Description>               
30                <NS_Component><!-- Radiation Scheme -->
31                    <NS_Name>Radiation Scheme</NS_Name>
32                    <NS_ComponentType>Atmosphere</NS_ComponentType>
33                    <NS_Description> 
34                        A general 2-stream radiation code including cloud microphysics.
35                        The radiation scheme uses 6 spectral bands in the solar (shortwave) wavelenths
36                        and 9 bands in the terrestrial thermal (longwave) wavelengths.
37                        The radiative effects of CO2 and ozone are explicitly represented as well as oxygen, methane, N2O, CFC-11 and CFC-12.
38                        The LW and SW radiative effects of climatological distributions of sulphate, seasalt, soot and biomass aerosols are included.
39                        A cloud area parameterisation produces an Area Cloud Fraction which replaces the bulk value used in the radiation code.
40                        Mixed phase clouds containing both ice and water are segregated into separate sub-clouds for radiation calculations.
41                    </NS_Description>
42                    <NS_References>
43                        <NS_Reference>
44                            JM Edwards, Slingo A, 1996: Studies with a flexible new radiation code. 1. Choosing a configuration for a large-scale model
45                      QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, 122(531) 689-719
46                        </NS_Reference>
47                    </NS_References>
48                </NS_Component>
49                <NS_Component><!-- Land Surface Scheme -->
50                    <NS_Name>Land Surface Scheme</NS_Name>
51                    <NS_ComponentType>LandSurface</NS_ComponentType>
52                    <NS_Description>
53                        The surface albedo is a function of snow depth and the temperature of the snow over sea ice.
54                        The surface hydrology uses the MOSES-II (Met Office Surface Exchange Scheme).
55                        The vegetation distribution is fixed.
56                        Using coastal tiling allows both land and sea to co-exist in the same gridbox.
57                        There are 9 land surface tiles per grid cell.
58                    </NS_Description>
59                    <NS_References>
60                        <NS_Reference>
62                            JOURNAL OF CLIMATE 8 (2): 240-247
63                        </NS_Reference>
64                    </NS_References>
65                </NS_Component>
66                <NS_Component><!-- Boundary Layer Scheme -->
67                    <NS_Name>Boundary Layer Scheme</NS_Name>
68                    <NS_ComponentType>Atmosphere</NS_ComponentType>
69                    <NS_Description>
70                        The boundary layer scheme explicitly parameterises the top-of-mixed-layer entrainment.
71                        It uses a formulation of the surface exchange coefficients based directly on Monin-Obukhov stability functions.
72                        It uses a subgrid diagnosis of cloud-base height in order to improve the accuracy of the buoyancy flux integral
73                        which is used to diagnose the depth of mixing in stratocumulus clouds.                                       
74                        The boundary layer scheme splits the radiative heating increments into separate LW and SW contributions. 
75                        It uses a Richardson number based mixing scheme and orographic roughness fields.
76                        The scheme accounts for the radiative coupling and the thermal capacity of the vegetation canopy.
77                    </NS_Description>
78                    <NS_References>
79                        <NS_Reference>Lock, A. P. 2001: The numerical representation of entrainment in parametrizations of boundary layer turbulent mixing.
80                            MWR, 129, 1148-1163
81                        </NS_Reference>
82                        <NS_Reference>Lock, A. P., A. R. Brown, M. R. Bush, G. M. Martin, R. N. B. Smith et al. 2000:
83                            A new boundary layer mixing scheme. Part I: scheme description and SCM tests. MWR, 128, 3187-3199
84                        </NS_Reference>
85                    </NS_References>
86                </NS_Component>
87                <NS_Component><!-- Convection Scheme -->
88                    <NS_Name>Convection Scheme</NS_Name>
89                    <NS_ComponentType>Atmosphere</NS_ComponentType>
90                    <NS_Description>
91                        Convection is able to transport momentum in the vertical.
92                        The inital convective plume mass flux is determined by a CAPE based clousure scheme.
93                        The radiative representation of anvils modifies the convective cloud amount (CCA) to vary with height during deep convection.
94                        Excluding precipitation from the water path means that the radiation scheme does not 'see' the convective rain and snow.
95                        The accurate treatment of precipitation phase change ensures that precipitation does not change phase if the associated latent
96                        cooling would take the temperature below the freezing point again.
97                    </NS_Description>
98                    <NS_References>
99                        <NS_Reference></NS_Reference>
100                        <NS_Reference></NS_Reference>
101                    </NS_References>
102                </NS_Component>
103                <NS_Component><!-- Gravity Wave Scheme -->
104                    <NS_Name>Gravity Wave Scheme</NS_Name>
105                    <NS_ComponentType>Atmosphere</NS_ComponentType>
106                    <NS_Description>
107                        The orographic gravitity wave scheme also includes flow blocking.
108                        The gravity wave constant is 1.00e+05 and defines the magnitude of the parametrized response.
109                        The critical Froude number is 4.00 and determines the proportion of that drag attributed to flow blocking and gravity wave drag respectively.
110                        The spectral gravity wave scheme is not used.
111                    </NS_Description>
112                    <NS_References>
113                        <NS_Reference>Webster S., A.R. Brown, D.R. Cameron and C.P. Jones, 2003:
114                            Improvements to the Representation of Orography in the Met Office Unified Model.
115                            Quarterly Journal of the Royal Meteorological Society, 129 (591): 1989-2010 Part B.
116                        </NS_Reference>
117                    </NS_References>
118                </NS_Component>
119                <NS_Component><!-- Precipitation and Cloud Scheme -->
120                    <NS_Name>Precipitation and Cloud Scheme</NS_Name>
121                    <NS_ComponentType>Atmosphere</NS_ComponentType>
122                    <NS_Description> The large scale precipitation scheme contains a full microphysical calculation of the cloud phase and
123                        generation of precipitation with water vapour, cloud liquid water and ice particle content as prognostic variables.
124                        Microphysical processes are treated as transfer terms between water vapour, liquid, ice, and rain.
125                        The fraction of cloud ice content that is pristine ice crystals and snow aggregate particles are treated
126                        seperately in the microphysical transfer terms.     
127                        Condensation can occur before grid scale supersaturation and the vapour is condensed to cloud water.
128                        The conversion from vapour to liquid or frozen cloud water is reversible.
129                        A RHcrit parametrization causes the cloud scheme to use 3D diagnosed critical relative humidity.
130                        A cloud area parametrization produces an Area Cloud Fraction which replaces the Bulk value in much of the radiation code.
131                    </NS_Description>
132                    <NS_References>
133                        <NS_Reference>Wood et al. ,2002: Atmos. Res., 65, 109-128</NS_Reference>
134                        <NS_Reference></NS_Reference>
135                        <NS_Reference></NS_Reference>
136                     </NS_References>
137                </NS_Component>
138                <NS_Component><!-- Advection and Diffusion -->
139                    <NS_Name>Advection and Diffusion</NS_Name>
140                    <NS_ComponentType>Atmosphere</NS_ComponentType>
141                    <NS_Description>
142                        A semi-lagrangian advection scheme is used.
143                        The advection of potential temperature, moisture, density and winds are treated separately.
144                        Moisture is conserved using a non-hydrostatic scheme.
145                        A conservative horizontal diffusion scheme is used.
146                        Vertical diffusion is switched off.
147                    </NS_Description>
148                    <NS_References>
149                        <NS_Reference>
151                        </NS_Reference>
152                    </NS_References>
153                </NS_Component>
154                <NS_Component><!-- Aerosols -->
155                    <NS_Name>Aerosols</NS_Name>
156                    <NS_ComponentType>Atmosphere</NS_ComponentType>
157                    <NS_Description>
158                        The aerosol parameterisation includes a sulphur cycle, soot scheme and biomass aerosol scheme.
159                        The sulphur cycle includes SO2 emissions from the surface, chimneys and volcanoes.
160                        The sulphur cycle also uses an interactive dimethyl sulphide scheme.
161                        The biomass scheme includes emissions from the surface and from high levels.
162                    </NS_Description>
163                </NS_Component>
164                <NS_Component><!-- Rivers -->
165                    <NS_Name>Rivers</NS_Name>
166                    <NS_ComponentType>LandSurface</NS_ComponentType>
167                    <NS_Description>
168                        All rivers flow with an effective velocity of 0.4 m/s and a meander ratio of 1.4.
169                        River outflow to the ocean is included.
170                    </NS_Description>
171                </NS_Component>
172            </NS_Component>           
173            <NS_Component><!-- OCEAN -->
174                <NS_Name>Ocean</NS_Name>
175                <NS_ComponentType>Ocean</NS_ComponentType>
176                <NS_Description><!-- SPACE AND TIME -->
177                    The oceanic component of HiGEM has 40 vertical levels with
178                    a horizontal resolution of 0.333 degrees of latitude by 0.333 degrees of longitude,
179                    which produces a global grid of 1082 x 540 grid cells. This is equivalent to a surface
180                    resolution of about 37 km x 37 km at the Equator, reducing to 26 km x 37 km
181                    at 45 degrees of latitude (comparable to a spectral resolution of Nblah).
182                    The atmospheric timestep period is 20 minutes (72 timesteps per 1 days).   
183                    The ocean GCM includes a polar island as standard.
184                    The ocean GCM uses the McDougall equation of state.
185                </NS_Description>
186                <NS_References>
187                    <NS_Reference></NS_Reference>
188                </NS_References>
189                <NS_Component><!-- tracer advection and diffusion-->
190                    <NS_Name>Tracer advection and diffusion</NS_Name>
191                    <NS_ComponentType>Ocean</NS_ComponentType>
192                    <NS_Description>
193                        The advection of active tracers, temperature and salinity, uses a fourth order differencing scheme (Pacanowski and Griffies, 1998)
194                        which uses a fourth order estimate of the tracer gradients together with the second order advective fluxes.                     
195                        The option to use upwind advection in the bottom gridcell at each point avoids instabilities found in high resolution runs.
196                        The Griffies diffusion scheme orientates the mixing tensor to lie along isopycnal rather than horizontal sufarces (Griffies et al., 1998).
197                        Isopycnal diffusivity is 5.00e+02 (m*m/s) and is constant with depth.
198                        The Gent and McWilliams (GM) Scheme parametrises the effect of mesoscale eddies on tracer transports.
199                        The Visbeck scheme allows the diffusivity for the GM scheme to be spatially and temporally variable,
200                        so that it can take large values in eddy-generation regions and small values elsewhere.
201                        The HADCM4 version of the Visbeck scheme uses large-scale density gradients to pick out eddy-generation regions.
202                        The isopycnal diffusivity is tapered as the slope of the isopycnals increases using a hyperbolic tangent function.
203                        A scale-selective version of the Gent and McWilliams scheme (Roberts and Marshall 1998) removes small-scale noise from the tracer fields
204                        without affecting their large-scale distribution and without causing any mixing across isopycnal surfaces.
205                    </NS_Description>
206                    <NS_References>
207                        <NS_Reference>Pacanowski and Griffies, MOM 3.0 Manual, 1998</NS_Reference>
208                        <NS_Reference></NS_Reference>
209                        <NS_Reference>Griffies et al 1998</NS_Reference>
210                        <NS_Reference>Roberts and Marshall, 1998</NS_Reference>
211                    </NS_References>
212                </NS_Component>               
213                <NS_Component><!-- Fourier filtering at high latitudes -->
214                    <NS_Name>Filtering</NS_Name>
215                    <NS_ComponentType>Ocean</NS_ComponentType>
216                    <NS_Description>
217                        Fourier filtering is used to decrease the effective resolution of the model at
218                        high latitudes, allowing a longer timestep to be used. See UMDP 40. Different
219                        filtered regions can be chosen for tracers and velocity and for the northern
220                        and southern hemispheres. In the northern hemisphere, filtering starts at
221                        'First tracer/velocity row in northern hemisphere to be filtered' and goes
222                        right up to the north pole. The filtering removes scales less than the grid
223                        scale on the row defined by 'Tracer/velocity row used to define basic zonal
224                        dimension'. The equator-most row to be filtered in each hemisphere determines
225                        the minimum effective gridlength retained by the filtering.
226                        The first tracer/velocity row in the northern hemisphere: 510/509
227                        Tracer/velocity row used to define basic zonal dimensions: 510/509
228                        The last tracer/velocity row in the southern hemisphere:34/34
229                    </NS_Description>
230                    <NS_References>
231                        <NS_Reference></NS_Reference>
232                    </NS_References>
233                </NS_Component>
234                <NS_Component><!-- Mixed layer and vertical diffusion-->
235                    <NS_Name>Mixed Layer and vertical diffusion</NS_Name>
236                    <NS_ComponentType>Ocean</NS_ComponentType>
237                    <NS_Description>
238                        A Kraus-Turner (1967) type mixed layer model is used to parameterise the effects of surface generated turbulence.
239                        Vertical diffusion is dependent on the Ricardson Number (Peters et al, ?)
240                        The quadratic Large scheme calculates the vertical diffusion coefficient in the mixed layer (Large et al 1994)
241                        The quadratic Large scheme is applied where the Richardson number is less than 0.3 upto a maximum depth of 80 m.
242                    </NS_Description>
243                    <NS_References>
244                        <NS_Reference>Kraus Turner, 1967</NS_Reference>
245                        <NS_Reference></NS_Reference>
246                        <NS_Reference>Peters et al, ?</NS_Reference>
247                        <NS_Reference>W.G.Large et al 1994, Oceanic Vertical Mixing : A review and a model
248                        with a nonlocal boundary layer parametrisation, Rev Geophys, 32, 363-403.</NS_Reference>
249                    </NS_References>
250                </NS_Component>
251                <NS_Component><!-- Barotropic Solution, Momentum Flux and Diffusion -->
252                    <NS_Name>Barotropic Solution, Momentum Flux and Diffusion</NS_Name>
253                    <NS_ComponentType>Ocean</NS_ComponentType>
254                    <NS_Description> 
255                        A free-surface barotropic solution is used with Delphus-Delcross smoothing for the surface height field.
256                        A modifed Cox scheme is used for calculating velocity fluxes.
257                        Horizontal momentum diffusion uses viscosity coeffiecients that are constant in latitude: 0.00.
258                        Biharmonic momentum diffusion allows scale-selective damping to be applied to the velocities
259                        without affecting the large-scale velocity field. It is useful in helping the removal of grid-scale noise in the velocity field.
260                    </NS_Description>
261                </NS_Component>
262                <NS_Component><!-- Convection -->
263                    <NS_Name>Convection</NS_Name>
264                    <NS_ComponentType>Ocean</NS_ComponentType>
265                    <NS_Description>
266                        A Rahmstorf's full convection scheme is used which
267                        is guaranteed to produce a profile having complete static stability.
268                    </NS_Description>
269                </NS_Component>
270                <NS_Component><!-- Salinity Control -->
271                    <NS_Name>Salinity Control</NS_Name>
272                    <NS_Description>
273                        There is no reference salinity, instead salinity limits are applied.
274                        Upper salinity limit: 4.50000e-02 (psu/1000).
275                        Lower salinity limit: 5.00000e-03 (psu/1000).
276                    </NS_Description>
277                </NS_Component>
278                <NS_Component><!-- Ocean straits -->
279                    <NS_Name>Ocean Straits</NS_Name>
280                    <NS_ComponentType>Ocean</NS_ComponentType>
281                    <NS_Description>
282                        A generalised strait exchange scheme is used that advects water from a marginal sea into the main                                   
283                        ocean, with a corresponding return flow.
284                        There is 1 strait in this set up with end coordinates (i,j) at (62, 378) and (65, 378).
285                    </NS_Description>
286                </NS_Component>               
287            </NS_Component>         
288            <NS_Component><!-- SEA ICE (part of ocean scheme really)-->
289                <NS_Name>Sea Ice</NS_Name>
290                <NS_ComponentType>Cryosphere</NS_ComponentType>
291                <NS_Description><!-- Sea Ice -->
292                    The prognostic sea ice model contains ice thermodynamics based on
293                    Semtner's "zero-layer" and calculates prognostic ice depth, ice concentration and snow depth.   
294                    The multiple ice categories model allows the sub-grid scale ice thickness distribution to be represented.
295                    The EVP (elastic-viscous-plastic) dynamics based on Hibler's sea-ice rheology calculates velocities
296                    that are used to advect sea-ice.
297                    A north polar island is included and sea ice can be advected over it.
298                </NS_Description>
299                <NS_References>
300                    <NS_Reference>
301                        Semtner, A. J., 1976:
302                        A model for the thermodynamic growth of sea ice in numerical investigations of climate.
303                        J. Phys. Oceanogr., 6, 379-389.
304                    </NS_Reference>
305                    <NS_Reference>
306                        Hibler, W. D., 1979: Dynamic Thermodynamic Sea Ice Model.
307                        Journal of Physical Oceanography, 9(4), 815-846.
308                    </NS_Reference>
309                </NS_References>
310                <NS_Component><!-- Sea Ice Thermodynamics -->
311                    <NS_Name>Sea Ice Thermodynamics</NS_Name>
312                    <NS_ComponentType>Cryosphere</NS_ComponentType>
313                    <NS_Description>
314                        Ocean to ice heat flux parameterisation uses the 'McPhee scheme'
315                        (McPhee, 1992), which uses both the ocean-ice temperature difference and
316                        the friction velocity in the flux parameterisation. 
317                        The 'McPhee scheme'  produces a flux proportional to the ice concentration
318                        above a marginal sea ice concentration of 0.05.  For lower concentrations,
319                        the heat flux is constant.
321                        Number of sea ice categories is 5.                       
322                        Minimum local ice depth is 0.1 m.
323                        Min local snow thickness: 1.0E-5 m                       
324                        Min local thickness of new ice growing in leads: 0.05m
325                    </NS_Description>
326                    <NS_References>
327                        <NS_Reference>
328                            McPhee, M. G., 1992: Turbulent heat-flux in the upper ocean under sea ice.
329                            Journal of Geophysical Research-Oceans, 97(C4), 5365-5379.
330                        </NS_Reference>
331                        <NS_Reference>
332                            Maykut G. A., M.G. McPhee, 1995: Solar heating of the Arctic mixed layer
333                            Journal of Geophysical Research-Oceans, 100(C12), 24691-24703.
334                        </NS_Reference>
335                    </NS_References>
336                </NS_Component>
337                <NS_Component><!-- Sea Ice Dynamics -->
338                    <NS_Name>Sea Ice Dynamics</NS_Name>
339                    <NS_ComponentType>Cryosphere</NS_ComponentType>
340                    <NS_Description>
341                        The sea ice velocity arises from a balance of windstress, ocean drag, coriolis and internal ice stresses.
342                        It is based on the viscous-plastic sea-ice rheology of Hibler (1979), and recommended for use in
343                        climate modelling by the Sea Ice Model Intercomparison Project [Kreyscher et al, 2000].
344                        Convergence of ice is impeded or prevented when the ice is thick.
345                        The ice ridging scheme converts thinner ice to thicker ice, and if the ice is converging, the scheme
346                        ensures that enough ice ridges to keep the ice concentration equal or below 1 (Hunke and Lipscomb).   
348                        Maximum compressive strength of ice per unit thickness is 2.00e+04 (N/m**2)
349                        Ice strength is smoothed to avoid instabilities at high northern latitudes polewards of 87.5 lat..
350                        Ice velocities are filtered at high northern latiitudes to prevent excessive ridging and buildup of ice.
351                        The Quadratic ice-ocean drag coefficient is 1.50e-02
352                    </NS_Description>
353                    <NS_References>
354                        <NS_Reference>
355                            Hibler, W. D., 1979: Dynamic Thermodynamic Sea Ice Model.
356                            Journal of Physical Oceanography, 9(4), 815-846.                           
357                        </NS_Reference>
358                        <NS_Reference>
359                            Kreyscher M et al., 2000: Results of the Sea Ice Model Intercomparison Project:
360                            Evaluation of sea ice rheology schemes for use in climate simulations
361                            Journal of Geophysical Research-Oceans, 105 (C5): 11299-11320.                             
362                        </NS_Reference>
363                        <NS_Reference>
364                            Thorndike, A. S., D. A. Rothrock, G. A. Maykut et al., 1975:
365                            Thickness Distribution of Sea Ice.
366                            Journal fo Geophysical Research-Oceans and Atmosphereres, 80(33), 4501-4513.
367                        </NS_Reference>
368                        <NS_Reference>
369                            Flato, G. M. and W. D. Hibler, 1995:
370                            Ridging and strength in modeling the thickness distribution of arctic sea-ice.
371                            Journal of Geophysical Research-Oceans, 100 (C9), 18611-18626.                       
372                        </NS_Reference>
373                        <NS_Reference>
374                            Lipscomb, W.H. and E. C. Hunke, 2004: Modeling sea ice transport using incremental remapping.
375                            Monthly Weather Review, 132 (6), 1341-1354.
376                        </NS_Reference>
377                    </NS_References>
378                </NS_Component>
379            </NS_Component>
380            <NS_Component>
381                <NS_Name>Atmos-Ocean Coupler</NS_Name>
382                <NS_ComponentType>Coupler</NS_ComponentType>
383                <NS_Description> 
384                </NS_Description>
385            </NS_Component>
386        </NS_Model>
387    </NS_CodeBase>
388    <NS_Experiment>
389        <NS_Description></NS_Description>
390        <NS_BoundaryCondition NS_Type="Present Day">
391            <NS_Description></NS_Description>
392        </NS_BoundaryCondition>
393        <NS_InitialCondition NS_Type="Unknown">
394            <NS_Description></NS_Description>
395        </NS_InitialCondition>
396    </NS_Experiment>
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