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revision 1.8 by dimitri, Fri Jan 18 17:33:56 2008 UTC revision 1.10 by dimitri, Mon Feb 25 16:50:56 2008 UTC
# Line 1  Line 1 
1    % $Header$
2    % $Name$
3  \documentclass[12pt]{article}  \documentclass[12pt]{article}
4    
5  \usepackage[]{graphicx}  \usepackage[]{graphicx}
# Line 50  Line 52 
52  \maketitle  \maketitle
53    
54  \begin{abstract}  \begin{abstract}
55    Some blabla  
56    As part of ongoing efforts to obtain a best possible synthesis of most
57    available, global-scale, ocean and sea ice data, dynamic and thermodynamic
58    sea-ice model components have been incorporated in the Massachusetts Institute
59    of Technology general circulation model (MITgcm).  Sea-ice dynamics use either
60    a visco-plastic rheology solved with a line successive relaxation (LSR)
61    technique, reformulated on an Arakawa C-grid in order to match the oceanic and
62    atmospheric grids of the MITgcm, and modified to permit efficient and accurate
63    automatic differentiation of the coupled ocean and sea-ice model
64    configurations.
65    
66  \end{abstract}  \end{abstract}
67    
68  \section{Introduction}  \section{Introduction}
# Line 134  The maximum ice pressure $P_{\max}$, a m Line 146  The maximum ice pressure $P_{\max}$, a m
146  both thickness $h$ and compactness (concentration) $c$:  both thickness $h$ and compactness (concentration) $c$:
147  \begin{equation}  \begin{equation}
148    P_{\max} = P^{*}c\,h\,e^{[C^{*}\cdot(1-c)]},    P_{\max} = P^{*}c\,h\,e^{[C^{*}\cdot(1-c)]},
149  \label{icestrength}  \label{eq:icestrength}
150  \end{equation}  \end{equation}
151  with the constants $P^{*}$ and $C^{*}$. The nonlinear bulk and shear  with the constants $P^{*}$ and $C^{*}$. The nonlinear bulk and shear
152  viscosities $\eta$ and $\zeta$ are functions of ice strain rate  viscosities $\eta$ and $\zeta$ are functions of ice strain rate
# Line 435  These reduced viscosities lead to small Line 447  These reduced viscosities lead to small
447  which in turn can have a strong effect on solutions in the limit of  which in turn can have a strong effect on solutions in the limit of
448  nearly rigid regimes (arching and blocking, not shown).  nearly rigid regimes (arching and blocking, not shown).
449    
450    \ml{[Say something about performance? This is tricky, as the
451      perfomance depends strongly on the configuration. A run with slowly
452      changing forcing is favorable for LSR, because then only very few
453      iterations are required for convergences while EVP uses its fixed
454      number of internal timesteps. If the forcing in changing fast, LSR
455      needs far more iterations while EVP still uses the fixed number of
456      internal timesteps. I have produces runs where for slow forcing LSR
457      is much faster than EVP and for fast forcing, LSR is much slower
458      than EVP. EVP is certainly more efficient in terms of vectorization
459      and MFLOPS on our SX8, but is that a criterion?]}
460    
461  \subsection{C-grid}  \subsection{C-grid}
462  \begin{itemize}  \begin{itemize}
463  \item no-slip vs. free-slip for both lsr and evp;  \item no-slip vs. free-slip for both lsr and evp;
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