source: NEMO/trunk/RELEASE_NOTES.rst @ 10150

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First version of release notes for upcoming 4.0

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1================
2NEMO 4.0 Release
3================
4
5.. contents::
6
7----------
8What's new
9----------
10
11Original sea-ice component SI\ :sup:`3`\
12========================================
13
14| Meeting in 2017, the `sea ice working group`_ decided to gather sea ice developers and
15  scientific expertise within the NEMO community in order to build a unified model.
16  The replacement of LIM (Louvain-la-Neuve Ice Model) has required the backport of
17  the desired functionalities from each of CICE, GELATO and LIM into a common code in the NEMO framework.
18| This new model has been named SI\ :sup:`3`\ ("sea ice cubed") and
19  means "**Sea Ice modelling Integrated Initiative**".
20
21- Physics
22
23  * Landfast ice: simple grounding with a "release" stress (not fully operational)
24  * Lateral melting
25  * Melt ponds: constant or `Holland 2012`_ formulation (and soon topographic melt ponds)
26  * Ice-atm. drags from `Lupkes 2012`_ (depending on ice concentration) or `Lupkes 2014`_
27    (Depending on sea ice concentration and atm. stability)
28- Numerics
29
30  * Advection: Ultimate-Macho scheme
31  * Rheology: adaptive EVP (`Kimmritz 2016`_)
32  * Coupling interface: conductivity as surface forcing instead of heat fluxes (Met Office requirement)
33- Performance
34
35  * All thermodynamics in 1D
36  * Reduced mpp communications
37- Users & developers friendly
38
39  * Comprehensive set of outputs (universal units and understandable names + includes limp)
40  * New architecture and namelist
41  * All processes can be decoupled from each other (switch on/off)
42  * Ice categories bounds can be defined by the user or set automatically
43  * For open boundaries, the number of ice categories from the forcing model can be different
44    from the number of categories in the regional simulation
45  * Fully compatible with AGRIF
46
47First Test Cases
48================
49
50Define and install a separate repository for test cases to all easy contributions from the NEMO Users Community
51
52+-------------------+--------------------------------------------------------+------------------------------------+
53| Name              | Purpose                                                | References                         |
54+===================+=================+======================================+====================================+
55| ``CANAL``         | East-west periodic canal of variable size with several |                                    |
56|                   | initial states and associated geostrophic currents     |                                    |
57|                   | (zonal jets or vortex).                                |                                    |
58+-------------------+--------------------------------------------------------+------------------------------------+
59| ``ICEDYN``        | East-west + north-south periodic channel.              |                                    |
60|                   | The common configuration includes an AGRIF zoom (1:3)  |                                    |
61|                   | in the middle of the basin to test how an ice patch is |                                    |
62|                   | advected through it but one can also test the          |                                    |
63|                   | advection schemes (Prather and Ultimate-Macho) by      |                                    |
64|                   | removing the ``key_agrif`` in the CPP keys.            |                                    |
65+-------------------+--------------------------------------------------------+------------------------------------+
66| ``ISOMIP``        | Simple box configuration with an iceshelf with simple  | `Hunter 2006`_                     |
67|                   | geometry on top.                                       |                                    |
68|                   | The purpose of this test case is to evaluate the       |                                    |
69|                   | impact of various schemes and new development with     |                                    |
70|                   | iceshelf cavities.                                     |                                    |
71+-------------------+--------------------------------------------------------+------------------------------------+
72| ``LOCK_EXCHANGE`` | Classical fluid dynamics experiment that has been      | - `Haidvogel and Beckmann 1999`_   |
73|                   | adapted for testing advection schemes in ocean         | - `Burchard and Bolding 2002`_     |
74|                   | circulation models.                                    | - `Ilıcak 2012`_                   |
75|                   | This experiment can in particular illustrate the       |                                    |
76|                   | impact of different choices of numerical schemes       |                                    |
77|                   | and/or subgrid closures on spurious interior mixing.   |                                    |
78+-------------------+--------------------------------------------------------+------------------------------------+
79| ``OVERFLOW``      | Adapted from the non-rotating overflow configuration   | - `Haidvogel and Beckmann 1999`_   |
80|                   | Illustrates the impact of different choices of         | - `Ilıcak 2012`_                   |
81|                   | numerical schemes and/or subgrid closures on spurious  |                                    |
82|                   | interior mixing close to bottom topography.            |                                    |
83+-------------------+--------------------------------------------------------+------------------------------------+
84| ``VORTEX``        | Illustrates the propagation of an anticyclonic eddy    | - `Debreu 2012`_                   |
85|                   | over a Beta plan and flat bottom.                      | - `Penven 2006`_                   |
86|                   | It is implemented here with an online refined          | - `Spall and Holland 1991`_        |
87|                   | subdomain (thanks to AGRIF library) out of which the   |                                    |
88|                   | vortex propagates and serves as a benchmark to         |                                    |
89|                   | diagnose nesting errors.                               |                                    |
90+-------------------+--------------------------------------------------------+------------------------------------+
91| ``WAD``           | Set of simple closed basin geometries for testing the  |                                    |
92|                   | wetting and drying capabilities.                       |                                    |
93|                   | Examples range from a closed channel with EW linear    |                                    |
94|                   | bottom slope to a parabolic EW channel with a Gaussian |                                    |
95|                   | ridge.                                                 |                                    |
96+-------------------+--------------------------------------------------------+------------------------------------+
97
98-----------
99Improvments
100-----------
101
102Core components
103===============
104
105Passive tracer TOP and biogeochemical PISCES components
106-------------------------------------------------------
107
108- The passive tracers transport component was redesigned toward a modular structure and
109  users can enable each module directly through logical flags in namelist_top (no more Fortran macros!).
110- TOP on-line user documentation is available on NEMO Trac platform (TOP-UserQuickGuide_)
111- TOP currently accounts for the following 5 modules:
112
113  * ``CFC`` contains inorganic carbon tracers (CFC11/CFC12/SF6)
114  * ``MY_TRC`` is a template for new modules (or external couplings)
115  * ``AGE`` deals with water age tracking
116  * ``C14`` as a radiocarbon passive tracer
117  * ``PISCES`` the companion ecosystem model
118- A generalized infrastructure was developed to handle the prescription of either surface, coastal, or
119  open boundaries conditions for each passive tracer.
120- PISCES model contains new developments and modifications:
121
122  * Particulate Organic Carbon (POC) component comes with a new liability scheme,
123    while the former Kriest parameterisation was superseded;
124  * A complex iron chemistry scheme is now available, with an improved description of ligands for
125    the marine iron cycle
126  * Carbonate chemistry is based on MOCSY 2.0 routines (see `Orr and Epitalon 2015`_),
127    by complying also with CMIP6 standards.
128  * Ecosystem components can be optionally modelled by means of explicit nutrient quotas (PISCES-QUOTA)
129
130AGRIF (embedded zooms)
131----------------------
132
133- Now compatible with new sea ice component and z* coordinate
134- Extended ghost cells area to properly handle scheme with spatial order >2
135- Added vertical refinement (beta)
136- Nesting tools for setup now up to date and working
137
138Adding of 3 Reference Configurations
139------------------------------------
140
141- ``AGRIF_DEMO``: 2 interlocked zooms (1:4 & 1:3) in the Nordic Seas + 1 zoom (1:1) at the equator
142- ``ORCA2_OFF_TRC``: a benchmark simulation environment to deal with inert carbon tracers dynamics by
143  exploiting the offline coupling with NEMO.
144- ``SPITZ12``: regional configuration around the Svalbard archipelago.
145
146Misc. improvments
147=================
148
149Physics
150-------
151
152- Bulk formulae : move to aerobulk package (`Brodeau 2017`_), i.e. NCAR, COARE and ECMWF bulk
153  (remove Clio and MFS bulk)
154- Fix for tracer conservation with split explicit free surface
155- Wetting and drying
156- iso-neutral mixing (iso and triad operators): add the Method of Stabilizing Correction (MSC)
157  (more accurate calculation) + add a bilaplacian case
158- Lateral physics (LDF): scale aware setting of eddy viscosity and diffusivity
159- Wave coupling: large scale wave interaction process added in momentum and tracer equations
160- Remove the acceleration of convergence
161 
162Numerics
163--------
164
165- Added tidal self attraction and loading either read from a file or from usual "scalar" approximation
166- Vertical physics (ZDF) (modularity, share shear production calculation between TKE and GKS,
167  removal of all ZDF CPP keys, removal of avmu & avmv, minimization of MPP comm.: ~15 removed)
168- Remove the split-explicit ZDF scheme for both TRA and DYN
169- Lateral physics (LDF): simplification of user interface and removal of CPP keys
170- Add a 4th order centered (CEN) and Flux Corrected Transport (FCT) tracer advection
171  (using a 4th compact in the vertical)
172- Generalised lbc_lnk and lbc_nfd
173- Configuration interface completely rewritten (DOM module mainly suppressed,
174  and in place: domain_cfg.nc file, or usr_def module)
175- Vorticity: 2 new energy conserving scheme:  ENT with Coriolis defined at T-point
176  (better for Flux form) and EET a variant of EEN where e3t is used instead of e3f
177  (solved the issue with e3f specification but is not enstrophy conserving)
178- Wave coupling: coupled interface to external wave model
179
180Performances
181------------
182
183- MPI Message passing recoded to reduce number of MPI communications (suppression of redundant communications,
184  gather multiple communications into one)
185- Back to standard dynamical allocation (remove of wrk_alloc/dealloc statements)
186- XIOS software for IOs version 2 as default, and optionally available for restarts
187- Unify mppini
188- Use non uniform jpi/jpj with dynamic allocation to avoid ghost rows/columns
189
190Environment
191-----------
192
193- Revised structure of namelist_ref/_cfg and default reference values.
194- Reorganisation of SVN repository to be compliant with usual directory tree and facilitate building of
195  NEMO executable
196- Improvements of reliability through automatic and regular testing of the changes made in repository
197
198.. _sea ice working group:       http://forge.ipsl.jussieu.fr/nemo/wiki/WorkingGroups/SI3
199.. _TOP-UserQuickGuide:          http://forge.ipsl.jussieu.fr/nemo/wiki/WorkingGroups/top-dg/TOP-UserQuickGuide
200
201.. _Hunter 2006:                 http://staff.acecrc.org.au/~bkgalton/ISOMIP/test_cavities.pdf
202.. _Brodeau 2017:                http://doi.org/10.1175/JPO-D-16-0169.1
203.. _Haidvogel and Beckmann 1999: http://hdl.handle.net/10013/epic.11761
204.. _Burchard and Bolding 2002:   http://www.researchgate.net/publication/258128069_GETM_A_General_Estuarine_Transport_Model_Scientific_Documentation
205.. _Ilıcak 2012:                 http://doi.org/10.1016/j.ocemod.2011.10.003
206.. _Debreu 2012:                 http://doi.org/10.1016/j.ocemod.2012.03.003
207.. _Penven 2006:                 http://doi.org/10.1016/j.ocemod.2005.05.002
208.. _Spall and Holland 1991:      http://www.researchgate.net/publication/232101325_A_Nested_Primitive_Equation_Model_for_Oceanic_Applications
209.. _Holland 2012:                http://doi.org/10.1175/JCLI-D-11-00078.1
210.. _Lupkes 2012:                 http://doi.org/10.1029/2012JD017630
211.. _Lupkes 2014:                 http://doi.org/10.1002/2014JD022418
212.. _Kimmritz 2016:               http://doi.org/10.1016/j.ocemod.2016.03.004
213.. _Orr and Epitalon 2015:       http://doi.org/10.5194/gmd-8-485-2015
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