Model dynamics - Revision history

RosDeath: /* function calcwdth */

2007-11-12T15:14:40Z

function calcwdth

2007-11-12T15:11:22Z

function calcwdth

2007-11-12T15:10:54Z

function calcwdth

2007-11-12T15:08:30Z

function calcwdth

2007-11-12T14:58:44Z

function calcflux

2007-11-09T17:20:49Z

function calcthck

2007-11-09T17:19:58Z

subroutine putpcgc

2007-11-09T17:19:50Z

function calcthck

2007-11-09T16:02:36Z

subroutine slapsolv

2007-11-09T16:00:13Z

subroutine slapsolv

@@ Line 42: / Line 42: @@
 This function returns the scaled width of the glacier.  This is determined using, <br>
-<math>w^{'}=w^{'}_{r}\left({\frac{H^{'}}{H^{'}_{r}}^{p}}\right) </math>
+<math>w^{'}=w^{'}_{r}\left({\frac{H^{'}}{H^{'}_{r}}}\right)^{p}+ w^{'}_{l}</math>
-where standard symbols are defined in Table 1, and wr and Hr are (scaled) reference widths and thickness.  The parameter p is typically 0.5 and is hard coded in the function, while w1 is a small number incorporated to stop width becoming zero in the vent of zero ice thickness (which is important in the ice thickness solver).
+where standard symbols are defined in , and <math>w_{r}</math> and <math>H_{r}</math> are (scaled) reference widths and thickness.  The parameter ''p'' is typically 0.5 and is hard coded in the function, while <math>w_{l}</math> is a small number incorporated to stop width becoming zero in the event of zero ice thickness (which is important in the ice thickness solver).
-This function is called from valley and the returned information is held in array wdth.
+This function is called from '''valley''' and the returned information is held in array '''wdth'''.

@@ Line 42: / Line 42: @@
 This function returns the scaled width of the glacier.  This is determined using, <br>
-<math>w^{'}=w^{'}_{r}/left({/frac{H^{'}}{H^{'}_{r}}^{p}}/right) </math>
+<math>w^{'}=w^{'}_{r}\left({\frac{H^{'}}{H^{'}_{r}}^{p}}\right) </math>
 where standard symbols are defined in Table 1, and wr and Hr are (scaled) reference widths and thickness.  The parameter p is typically 0.5 and is hard coded in the function, while w1 is a small number incorporated to stop width becoming zero in the vent of zero ice thickness (which is important in the ice thickness solver).
 This function is called from valley and the returned information is held in array wdth.

@@ Line 42: / Line 42: @@
 This function returns the scaled width of the glacier.  This is determined using, <br>
-<math>w^{'}=w^{'}_{r} </math>
+<math>w^{'}=w^{'}_{r}/left({/frac{H^{'}}{H^{'}_{r}}^{p}}/right) </math>
 where standard symbols are defined in Table 1, and wr and Hr are (scaled) reference widths and thickness.  The parameter p is typically 0.5 and is hard coded in the function, while w1 is a small number incorporated to stop width becoming zero in the vent of zero ice thickness (which is important in the ice thickness solver).
 This function is called from valley and the returned information is held in array wdth.

@@ Line 41: / Line 41: @@
 == function calcwdth ==
-This function returns the scaled width of the glacier.  This is determined using
+This function returns the scaled width of the glacier.  This is determined using, <br>
 where standard symbols are defined in Table 1, and wr and Hr are (scaled) reference widths and thickness.  The parameter p is typically 0.5 and is hard coded in the function, while w1 is a small number incorporated to stop width becoming zero in the vent of zero ice thickness (which is important in the ice thickness solver).
 This function is called from valley and the returned information is held in array wdth.

@@ Line 37: / Line 37: @@
 where standard symbols are defined in ''Table 1''. The flux is scaled and is determined on a staggered grid that has points positioned halfway between adjacent thickness grid points. The algorithm takes into account any branching in the system. If both up and downstream points have no ice then the flux is set to zero.<br>
-Note that this calculation is not needed for the main thickness-evolution calculation and is performed solely for diagnostic reasons. This function is called directly from valley and the returned information is held in array, '''''flux'''''.
+Note that this calculation is not needed for the main thickness-evolution calculation and is performed solely for diagnostic reasons. This function is called directly from '''valley''' and the returned information is held in array, '''''flux'''''.
 == function calcwdth ==

@@ Line 31: / Line 31: @@
 This subroutine is called from calcthck.
-function calcflux
+== function calcflux ==
 This function returns the total horizontal flux of ice along the glacier.  This is determined from,
 ::<math>Q^{'}=q^{'}w^{'}=-D^{'}w{'}\frac{\delta\,s^{'}}{\delta\,x^{'}}</math>
@@ Line 38: / Line 39: @@
 Note that this calculation is not needed for the main thickness-evolution calculation and is performed solely for diagnostic reasons. This function is called directly from valley and the returned information is held in array, '''''flux'''''.
 function calcwdth
 This function returns the scaled width of the glacier.  This is determined using
 where standard symbols are defined in Table 1, and wr and Hr are (scaled) reference widths and thickness.  The parameter p is typically 0.5 and is hard coded in the function, while w1 is a small number incorporated to stop width becoming zero in the vent of zero ice thickness (which is important in the ice thickness solver).
 This function is called from valley and the returned information is held in array wdth.

@@ Line 25: / Line 25: @@
 This simple subroutine fills a sparse matrix using the coefficients supplied.  The sparse matrix has a three column format (row, column and value) and can be used with the SLAP matrix algebra library.  The subroutine checks to ensure no zero values are entered.  The sparse matrix itself is held in module pcgdwk.
 This subroutine is called from calcthck and is called once per matrix element.
 === subroutine slapsolv ===

@@ Line 1: / Line 1: @@
-=== function calcthck ===
+The model dynamics allow the glacier thickness and width to evolve in response to the climate perturbations applied.
 This function returns ice thickness along the glacier at the new time including the effects of local mass balance and ice flow.  This is done using an implicit technique and is complicated by the need to incorporate the effect of possible branches in the glacier system.  The equation to be solved is,
 ::<math>\frac{\delta\,s} {\delta\,t}= b - \frac{1} {w}  \frac{\delta\,wq} {\delta\,x}</math> <br>
@@ Line 19: / Line 20: @@
 #With the matrix '''''A''''' and vector '''''b''''' filled, we can obtain '''''x''''' by standard matrix inversion algorithms (in this case SLAP, see '''[[slapsolve]]'''). We only do this if there is a significant length of glacier etc.
 #Finally, unpack the new surface elevations from the matrix inversion output to the appropriate positions in the surface elevation array (usrf) using information in mask, and then find new thicknesses using bedrock elevation (topg) and glacier length.
 === subroutine putpcgc ===