diff --git a/README.src/README.src.changes.3p01 b/README.src/README.src.changes.3p01 new file mode 100644 index 0000000..00d3a95 --- /dev/null +++ b/README.src/README.src.changes.3p01 @@ -0,0 +1,50 @@ +README.src/README.src.changes.3p01 + +Significant changes since 2.3.01: + +a) Added blkdat variable oneta0. 1+eta is the scale factor from depth +to depth + non-steric_SSH. So 1+eta=0.0 is dry land, which isn't allowed. +oneta0 sets a minimum on 1+eta. A typical value is 0.1, and there +will be entries in the model .log file if oneta is clipped to oneta0. + +b) Added blkdat variable lbmont. When HYCOM is run with sshflg=2 the +Montgomery potential is offset so that montg1 in an archive file +represents steric SSH. This makes tidal analysis easier since non-steric +SSH (including tides) is srfhgt-montg1. The Browning & Kreiss barotropic +open boundary reads montg1, and it needs to know if this is the original +field or the field corrected via sshflg=2. Hence the new blkdat variable +lbmont. This only has an effect when lbflag=2, and in all legacy cases +lbmont will be 0 (false). + +c) Added lmask_rdnest. Mean archives can contain large layer velocities +near the bottom because of a mismatch between the p-grid layer thickness +mean projected onto cell faces and u-grid and v-grid layer thickness means. +These no longer occur for means calculated by the running model, but old +in-line means and off-line means (e.g. monthly or annual) still have this +issue. To prevent these large velocities effecting the baroclinic nesting, +rdnest_in has a compile time parameter, lmask_rdnest, that, when .true., +masks nest velocities (sets rmunv to zero) when they are outside the +near-surface range. It is .false. unless CPP macro RDNEST_MASK is set. + +d) The Browning&Kreiss (latbdt) and Flather (latbdtf) barotropic nesting +routines have been overhauled. Flather now uses p-grid nested velocities, +[uv]pnst, as in Browning&Kreiss. The Browning&Kreiss normal transport now +always has an along port 1-2-1 smoother applied to it. Added a compile +time parameter, npline, to control how often pline is updated in latbdt. +It is set to 1 unless the CPP macro LATBDT_NPLINE3 sets it to 3. + +e) A new variable, sports, has been optionally added to ports.input. It is +a scale factor that is applied to all the nested barotropic velocities. Use +1.0 (the default if it is absent) to get the orignal velocities. If present, +it is the 1st line of ports.input: + 1.2 'sports' = scale factor for nested velocity (typically 1.0) + 6 'nports' = number of boundary port sections + +f) Added wndflg=-4,-5. When wndflg is set to 4 or 5 U10 winds are read in +and wind stress is calculated inside HYCOM using a bulk parameterization. +This can be based either on absolute winds (U10) or relative winds (U10-Uocn). +Previously, wndflg=4 always used relative winds and wndflg=5 recently used +absolute winds (although the original Large&Yeager parameterizion used +relative winds, and code for relative winds was included but commented out). +Now, wndflg=4,5 uses relative winds and the new options wndflg=-4,-5 use +absolute winds. Note that 2.3.00's wndflg=5 becomes 2.3.01's wndflg=-5.