Changeset 3609 for branches/2012/dev_NOC_2012_rev3555/DOC/TexFiles
- Timestamp:
- 2012-11-19T16:51:17+01:00 (12 years ago)
- Location:
- branches/2012/dev_NOC_2012_rev3555/DOC/TexFiles
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branches/2012/dev_NOC_2012_rev3555/DOC/TexFiles/Biblio/Biblio.bib
r3294 r3609 2064 2064 volume = {3}, 2065 2065 pages = {1--20} 2066 } 2067 2068 2069 @article{Martin_Adcroft_OM10, 2070 author = {T. Martin and A. Adcroft}, 2071 title = {Parameterizing the fresh-water flux from land ice to ocean with interactive icebergs in a coupled climate model}, 2072 journal = OM, 2073 year = {2010}, 2074 volume = {34}, number = {3--4}, 2075 pages = {111--124}, 2076 issn = {1463-5003}, 2077 doi = {10.1016/j.ocemod.2010.05.001}, 2078 url = {http://dx.doi.org/10.1016/j.ocemod.2010.05.001} 2066 2079 } 2067 2080 -
branches/2012/dev_NOC_2012_rev3555/DOC/TexFiles/Chapters/Chap_SBC.tex
r3607 r3609 1 1 % ================================================================ 2 % Chapter Ñ Surface Boundary Condition (SBC )3 % ================================================================ 4 \chapter{Surface Boundary Condition (SBC ) }2 % Chapter Ñ Surface Boundary Condition (SBC, ICB) 3 % ================================================================ 4 \chapter{Surface Boundary Condition (SBC, ICB) } 5 5 \label{SBC} 6 6 \minitoc … … 56 56 Next the scheme for interpolation on the fly is described. 57 57 Finally, the different options that further modify the fluxes applied to the ocean are discussed. 58 One of these is modification by icebergs (see \S\ref{ICB_icebergs}), which act as drifting sources of fresh water. 58 59 59 60 … … 921 922 %} 922 923 924 925 % ================================================================ 926 % Handling of icebergs 927 % ================================================================ 928 \section{ Handling of icebergs (ICB) } 929 \label{ICB_icebergs} 930 %------------------------------------------namberg---------------------------------------------------- 931 \namdisplay{namberg} 932 %------------------------------------------------------------------------------------------------------------- 933 934 Icebergs are modelled as lagrangian particles in NEMO. 935 Their physical behaviour is controlled by equations as described in \citet{Martin_Adcroft_OM10} ). 936 (Note that the authors kindly provided a copy of their code to act as a basis for implementation in NEMO.) 937 Icebergs are initially spawned into one of ten classes which have specific mass and thickness as described by 938 \np{rn\_initial\_mass} and \np{rn\_initial\_thickness}. 939 Each class has an associated scaling (\np{rn\_mass\_scaling}), which is an integer representing how many icebergs 940 of this class are being described as one lagrangian point (this reduces the numerical problem of tracking every single iceberg). 941 They are enabled by setting \np{ln\_icebergs}~=~true. 942 943 Two initialisation schemes are possible. 944 \begin{description} 945 \item[\np{nn\_test\_icebergs}~$>$~0] 946 In this scheme, the value of \np{nn\_test\_icebergs} represents the class of iceberg to generate 947 (so between 1 and 10), and \np{nn\_test\_icebergs} provides a lon/lat box in the domain at each 948 grid point of which an iceberg is generated at the beginning of the run. 949 (Note that this happens each time the timestep equals \np{nn\_nit000}.) 950 \np{nn\_test\_icebergs} is defined by four numbers in \np{nn\_test\_box} representing the corners 951 of the geographical box: lonmin,lonmax,latmin,latmax 952 \item[\np{nn\_test\_icebergs}~=~-1] 953 In this scheme the model reads a calving file supplied in the \np{sn\_icb} parameter. 954 This should be a file with a field on the configuration grid (typically ORCA) representing ice accumulation rate at each model point. 955 These should be ocean points adjacent to land where icebergs are known to calve. 956 Most points in this input grid are going to have value zero. 957 When the model runs, ice is accumulated at each grid point which has a non-zero source term. 958 At each time step, a test is performed to see if there is enough ice mass to calve an iceberg of each class in order (1 to 10). 959 Note that this is the initial mass multiplied by the number each particle represents ($i.e.$ the scaling). 960 If there is enough ice, a new iceberg is spawned and the total available ice reduced accordingly. 961 \end{description} 962 963 Icebergs are influenced by wind, waves and currents, bottom melt and erosion. 964 The latter act to disintegrate the iceberg. This is either all melted freshwater, or 965 (if \np{rn\_bits\_erosion\_fraction}~$>$~0) into melt and additionally small ice bits 966 which are assumed to propagate with their larger parent and thus delay fluxing into the ocean. 967 Melt water (and other variables on the configuration grid) are written into the main NEMO model output files. 968 969 Extensive diagnostics can be produced. 970 Separate output files are maintained for human-readable iceberg information. 971 A separate file is produced for each processor (independent of \np{ln\_ctl}). 972 The amount of information is controlled by two integer parameters: 973 \begin{description} 974 \item[\np{nn\_verbose\_level}] takes a value between one and four and represents 975 an increasing number of points in the code at which variables are written, and an 976 increasing level of obscurity. 977 \item[\np{nn\_verbose\_write}] is the number of timesteps between writes 978 \end{description} 979 980 Iceberg trajectories can also be written out and this is enabled by setting \np{nn\_sample\_rate}~$>$~0. 981 A non-zero value represents how many timesteps between writes of information into the output file. 982 These output files are in NETCDF format. 983 When \key{mpp\_mpi} is defined, each output file contains only those icebergs in the corresponding processor. 984 Trajectory points are written out in the order of their parent iceberg in the model's "linked list" of icebergs. 985 So care is needed to recreate data for individual icebergs, since its trajectory data may be spread across 986 multiple files. 987 988 923 989 % ================================================================ 924 990 % Miscellanea options … … 1101 1167 the expense of having more idle CICE processors in areas where there is no sea ice. 1102 1168 1103 1104 1169 % ------------------------------------------------------------------------------------------------------------- 1105 1170 % Freshwater budget control
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