[7547] | 1 | \include{Preamble} |
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| 2 | |
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| 3 | \begin{document} |
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| 4 | |
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[9024] | 5 | \title{Draft description of NEMO wetting and drying scheme: 29 November 2017 } |
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[7547] | 6 | |
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[9024] | 7 | \author{ Enda O'Dea, Hedong Liu, Jason Holt, Andrew Coward and Michael J. Bell } |
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[7547] | 8 | |
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| 9 | %------------------------------------------------------------------------ |
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| 10 | % End of temporary latex header (to be removed) |
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| 11 | %------------------------------------------------------------------------ |
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| 12 | |
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| 13 | % ================================================================ |
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| 14 | % Chapter Ocean Dynamics (DYN) |
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| 15 | % ================================================================ |
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| 16 | \chapter{Ocean Dynamics (DYN)} |
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| 17 | \label{DYN} |
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| 18 | \minitoc |
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| 19 | |
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| 20 | % add a figure for dynvor ens, ene latices |
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| 21 | |
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| 22 | $\ $\newline % force a new ligne |
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| 23 | |
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| 24 | % ================================================================ |
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| 25 | % Wetting and drying |
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| 26 | % ================================================================ |
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[7598] | 27 | |
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[7547] | 28 | %---------------------------------------------------------------------------------------- |
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| 29 | % The WAD test cases |
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| 30 | %---------------------------------------------------------------------------------------- |
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[10499] | 31 | \section [The WAD test cases (\textit{usrdef\_zgr})] |
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[7547] | 32 | {The WAD test cases (\mdl{usrdef\_zgr})} |
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| 33 | \label{WAD_test_cases} |
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| 34 | |
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[7609] | 35 | This section contains details of the seven test cases that can be run as part of the |
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[7547] | 36 | WAD\_TEST\_CASES configuration. All the test cases are shallow (less than 10m deep), |
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[7609] | 37 | basins or channels with 4m high walls and some of topography that can wet and dry up to |
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| 38 | 2.5m above sea-level. The horizontal grid is uniform with a 1km resolution and measures |
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| 39 | 52km by 34km. These dimensions are determined by a combination of code in the |
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| 40 | \mdl{usrdef\_nam} module located in the WAD\_TEST\_CASES/MY\_SRC directory and setting |
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| 41 | read in from the namusr\_def namelist. The first six test cases are closed systems with no |
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| 42 | rotation or external forcing and motion is simply initiated by an initial ssh slope. The |
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| 43 | seventh test case introduces and open boundary at the right-hand end of the channel which |
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| 44 | is forced with sinousoidally varying ssh and barotropic velocities. |
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[7547] | 45 | |
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| 46 | \namdisplay{nam_wad_usr} |
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| 47 | |
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[7609] | 48 | The $\mathrm{nn\_wad\_test}$ parameter can takes values 1 to 7 and it is this parameter |
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| 49 | that determines which of the test cases will be run. Most cases can be run with the |
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| 50 | default settings but the simple linear slope cases (tests 1 and 5) can be run with lower |
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| 51 | values of $\mathrm{rn\_wdmin1}$. Any recommended changes to the default namelist settings |
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| 52 | will be stated in the individual subsections. |
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[7547] | 53 | |
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[7609] | 54 | Test case 7 requires additional {\tt namelist\_cfg} changes to activate the open boundary |
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| 55 | and lengthen the duration of the run (in order to demonstrate the full forcing cycle). |
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| 56 | There is also a simple python script which needs to be run in order to generate the |
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[7610] | 57 | boundary forcing files. Full details are given in subsection (\ref{WAD_test_case7}). |
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[7609] | 58 | |
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| 59 | \clearpage |
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[10499] | 60 | \subsection [WAD test case 1 : A simple linear slope] |
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[7547] | 61 | {WAD test case 1 : A simple linear slope} |
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| 62 | \label{WAD_test_case1} |
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| 63 | |
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| 64 | The first test case is a simple linear slope (in the x-direction, uniform in y) with an |
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| 65 | adverse SSH gradient that, when released, creates a surge up the slope. The parameters are |
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| 66 | chosen such that the surge rises above sea-level before falling back and oscillating |
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| 67 | towards an equilibrium position. This case can be run with $\mathrm{rn\_wdmin1}$ values as |
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[7609] | 68 | low as 0.075m. I.e. the following change may be made to the default values in {\tt |
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| 69 | namelist\_cfg} (for this test only): |
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[7547] | 70 | |
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[7609] | 71 | \namdisplay{nam_wad_tc1} |
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| 72 | |
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[7547] | 73 | %>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> |
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[7609] | 74 | \begin{figure}[htb] \begin{center} |
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[7547] | 75 | \includegraphics[width=0.8\textwidth]{Fig_WAD_TC1} |
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| 76 | \caption{ \label{Fig_WAD_TC1} |
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| 77 | The evolution of the sea surface height in WAD\_TEST\_CASE 1 from the initial state (t=0) |
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| 78 | over the first three hours of simulation. Note that in this time-frame the resultant surge |
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| 79 | reaches to nearly 2m above sea-level before retreating.} |
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| 80 | \end{center}\end{figure} |
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| 81 | %>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> |
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| 82 | |
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[7609] | 83 | \clearpage |
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[10499] | 84 | \subsection [WAD test case 2 : A parabolic channel ] |
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[7547] | 85 | {WAD test case 2 : A parabolic channel} |
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| 86 | \label{WAD_test_case2} |
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| 87 | |
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[7609] | 88 | The second and third test cases use a closed channel which is parabolic in x and uniform |
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| 89 | in y. Test case 2 uses a gentler initial SSH slope which nevertheless demonstrates the |
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| 90 | ability to wet and dry on both sides of the channel. This solution requires values of |
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| 91 | $\mathrm{rn\_wdmin1}$ at least 0.3m ({\it Q.: A function of the maximum topographic |
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| 92 | slope?}) |
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[7547] | 93 | |
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[7609] | 94 | \namdisplay{nam_wad_tc2} |
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[7547] | 95 | |
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| 96 | %>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> |
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[7609] | 97 | \begin{figure}[htb] \begin{center} |
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[7547] | 98 | \includegraphics[width=0.8\textwidth]{Fig_WAD_TC2} |
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| 99 | \caption{ \label{Fig_WAD_TC2} |
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| 100 | The evolution of the sea surface height in WAD\_TEST\_CASE 2 from the initial state (t=0) |
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| 101 | over the first three hours of simulation. Note that in this time-frame the resultant sloshing |
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| 102 | causes wetting and drying on both sides of the parabolic channel.} |
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| 103 | \end{center}\end{figure} |
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| 104 | %>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> |
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| 105 | |
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[7609] | 106 | \clearpage |
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[10499] | 107 | \subsection [WAD test case 3 : A parabolic channel (extreme slope) ] |
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[7547] | 108 | {WAD test case 3 : A parabolic channel (extreme slope)} |
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| 109 | \label{WAD_test_case3} |
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| 110 | |
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[7609] | 111 | Similar to test case 2 but with a steeper initial SSH slope. The solution is similar but more vigorous. |
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[7547] | 112 | |
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[7609] | 113 | \namdisplay{nam_wad_tc3} |
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| 114 | |
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[7547] | 115 | %>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> |
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[7609] | 116 | \begin{figure}[htb] \begin{center} |
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[7547] | 117 | \includegraphics[width=0.8\textwidth]{Fig_WAD_TC3} |
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| 118 | \caption{ \label{Fig_WAD_TC3} |
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| 119 | The evolution of the sea surface height in WAD\_TEST\_CASE 3 from the initial state (t=0) |
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| 120 | over the first three hours of simulation. Note that in this time-frame the resultant sloshing |
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| 121 | causes wetting and drying on both sides of the parabolic channel.} |
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| 122 | \end{center}\end{figure} |
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| 123 | %>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> |
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| 124 | |
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[7609] | 125 | \clearpage |
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[10499] | 126 | \subsection [WAD test case 4 : A parabolic bowl ] |
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[7547] | 127 | {WAD test case 4 : A parabolic bowl} |
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| 128 | \label{WAD_test_case4} |
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| 129 | |
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| 130 | Test case 4 includes variation in the y-direction in the form of a parabolic bowl. The |
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| 131 | initial condition is now a raised bulge centred over the bowl. Figure \ref{Fig_WAD_TC4} |
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| 132 | shows a cross-section of the SSH in the X-direction but features can be seen to propagate |
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| 133 | in all directions and interfere when return paths cross. |
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| 134 | |
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[7609] | 135 | \namdisplay{nam_wad_tc4} |
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[7547] | 136 | |
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| 137 | %>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> |
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[7609] | 138 | \begin{figure}[htb] \begin{center} |
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[7547] | 139 | \includegraphics[width=0.8\textwidth]{Fig_WAD_TC4} |
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| 140 | \caption{ \label{Fig_WAD_TC4} |
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| 141 | The evolution of the sea surface height in WAD\_TEST\_CASE 4 from the initial state (t=0) |
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| 142 | over the first three hours of simulation. Note that this test case is a parabolic bowl with |
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| 143 | variations occurring in the y-direction too (not shown here).} |
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| 144 | \end{center}\end{figure} |
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| 145 | %>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> |
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| 146 | |
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[7609] | 147 | \clearpage |
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[10499] | 148 | \subsection [WAD test case 5 : A double slope with shelf channel ] |
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[7547] | 149 | {WAD test case 5 : A double slope with shelf channel} |
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| 150 | \label{WAD_test_case5} |
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| 151 | |
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| 152 | Similar in nature to test case 1 but with a change in slope and a mid-depth shelf. |
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| 153 | |
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[7609] | 154 | \namdisplay{nam_wad_tc5} |
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[7547] | 155 | |
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| 156 | %>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> |
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[7609] | 157 | \begin{figure}[htb] \begin{center} |
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[7547] | 158 | \includegraphics[width=0.8\textwidth]{Fig_WAD_TC5} |
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| 159 | \caption{ \label{Fig_WAD_TC5} |
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| 160 | The evolution of the sea surface height in WAD\_TEST\_CASE 5 from the initial state (t=0) |
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| 161 | over the first three hours of simulation. The surge resulting in this case wets to the full |
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| 162 | depth permitted (2.5m above sea-level) and is only halted by the 4m high side walls.} |
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| 163 | \end{center}\end{figure} |
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| 164 | %>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> |
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| 165 | |
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[7609] | 166 | \clearpage |
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[10499] | 167 | \subsection [WAD test case 6 : A parabolic channel with central bar ] |
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[7547] | 168 | {WAD test case 6 : A parabolic channel with central bar} |
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| 169 | \label{WAD_test_case6} |
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| 170 | |
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| 171 | Test cases 1 to 5 have all used uniform T and S conditions. The dashed line in each plot |
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| 172 | shows the surface salinity along the y=17 line which remains satisfactorily constant. Test |
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| 173 | case 6 introduces variation in salinity by taking a parabolic channel divided by a central |
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| 174 | bar (gaussian) and using two different salinity values in each half of the channel. This |
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| 175 | step change in salinity is initially enforced by the central bar but the bar is |
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| 176 | subsequently over-topped after the initial SSH gradient is released. The time series in |
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| 177 | this case shows the SSH evolution with the water coloured according to local salinity |
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| 178 | values. Encroachment of the high salinity (red) waters into the low salinity (blue) basin |
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| 179 | can clearly be seen. |
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| 180 | |
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[7609] | 181 | \namdisplay{nam_wad_tc6} |
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[7547] | 182 | |
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| 183 | %>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> |
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[7609] | 184 | \begin{figure}[htb] \begin{center} |
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[7547] | 185 | \includegraphics[width=0.8\textwidth]{Fig_WAD_TC6} |
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| 186 | \caption{ \label{Fig_WAD_TC6} |
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| 187 | The evolution of the sea surface height in WAD\_TEST\_CASE 6 from the initial state (t=0) |
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| 188 | over the first three hours of simulation. Water is coloured according to local salinity |
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| 189 | values. Encroachment of the high salinity (red) waters into the low salinity (blue) basin |
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| 190 | can clearly be seen although the largest influx occurs early in the sequence between the |
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| 191 | frames shown.} |
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| 192 | \end{center}\end{figure} |
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| 193 | %>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> |
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| 194 | |
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[7609] | 195 | \clearpage |
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[10499] | 196 | \subsection [WAD test case 7 : A double slope with shelf, open-ended channel ] |
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[7609] | 197 | {WAD test case 7 : A double slope with shelf, open-ended channel} |
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| 198 | \label{WAD_test_case7} |
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[7547] | 199 | |
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[7609] | 200 | Similar in nature to test case 5 but with an open boundary forced with a sinusoidally |
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| 201 | varying ssh. This test case has been introduced to emulate a typical coastal application |
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| 202 | with a tidally forced open boundary. The bathymetry and setup is identical to test case 5 |
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| 203 | except the right hand end of the channel is now open and has simple ssh and barotropic |
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| 204 | velocity boundary conditions applied at the open boundary. Several additional steps and |
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| 205 | namelist changes are required to run this test. |
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| 206 | |
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| 207 | \namdisplay{nam_wad_tc7} |
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| 208 | |
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| 209 | In addition, the boundary condition files must be generated using the python script |
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| 210 | provided. |
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| 211 | |
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| 212 | \begin{verbatim} |
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| 213 | python ./makebdy_tc7.py |
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| 214 | \end{verbatim} |
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| 215 | |
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| 216 | will create the following boundary files for this test (assuming a suitably configured |
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| 217 | python environment: python2.7 with netCDF4 and numpy): |
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| 218 | |
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| 219 | \begin{verbatim} |
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| 220 | bdyssh_tc7_m12d30.nc bdyuv_tc7_m12d30.nc |
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| 221 | bdyssh_tc7_m01d01.nc bdyuv_tc7_m01d01.nc |
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| 222 | bdyssh_tc7_m01d02.nc bdyuv_tc7_m01d02.nc |
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| 223 | bdyssh_tc7_m01d03.nc bdyuv_tc7_m01d03.nc |
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| 224 | \end{verbatim} |
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| 225 | |
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| 226 | These are sufficient for up to a three day simulation; the script is easily adapted if |
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| 227 | longer periods are required. |
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| 228 | |
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| 229 | %>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> |
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| 230 | \begin{sidewaysfigure}[htb] \begin{center} |
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| 231 | \includegraphics[width=0.8\textwidth]{Fig_WAD_TC7} |
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| 232 | \caption{ \label{Fig_WAD_TC7} |
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| 233 | The evolution of the sea surface height in WAD\_TEST\_CASE 7 from the initial state (t=0) |
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| 234 | over the first 24 hours of simulation. After the initial surge the solution settles into a |
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| 235 | simulated tidal cycle with an amplitude of 5m. This is enough to repeatedly wet and dry |
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| 236 | both shelves.} |
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| 237 | |
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| 238 | \end{center}\end{sidewaysfigure} |
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| 239 | %>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> |
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| 240 | |
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| 241 | |
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[7547] | 242 | % ================================================================ |
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| 243 | |
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[10499] | 244 | %\bibliographystyle{wileyqj} |
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| 245 | %\bibliographystyle{../../../doc/latex/NEMO/main/ametsoc.bst} |
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| 246 | %\bibliography{references} |
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[7547] | 247 | |
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| 248 | \end{document} |
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