Changes between Initial Version and Version 1 of PDAF_iau_init

Timestamp:

Mar 20, 2025, 6:22:35 PM (13 days ago)

Author:

lnerger

Comment:

--

PDAF_iau_init

@@ +1 @@
+= PDAF_iau_init = 
+
+This page documents the routine `PDAF_iau_init` of PDAF, which was introduced with PDAF V3.0.
+
+This routine initializes parameters for incremental analysis updating, IAU. It further allocates the array in which the ensmelbe increments are stored. This array exists on all processes that are model tasks
+
+The routine is usually called in init_pdaf after the initialization of PDAF in PDAF_init.
+
+
+The interface is the following:
+{{{
+  SUBROUTINE PDAF_iau_init(type_iau, nsteps_iau, flag)
+}}}
+with the following arguments:
+{{{
+    INTEGER, INTENT(in) :: type_iau     !< Type of IAU
+                                           !< (0) no IAU
+                                           !< (1) constant increment weight 1/nsteps_iau
+                                           !< (2) Linear IAU weight with maximum in middle of IAU period
+                                           !< (3) Zero weights for null mode (can be used to apply IAU on user side)
+    INTEGER, INTENT(in) :: nsteps_iau   !< number of time steps in IAU
+    INTEGER, INTENT(out) :: flag           !< Status flag
+}}}
+
+Hints:
+  * type_iau=2 is linearly increasing and decreasing similar to what is used in the ocean model NEMO. Thi sis usually used if the IAU is applied in re-running over the previous observation phase
+  * type_iau=3 stores the increment information, but does not apply the increment. This permits to apply the increment in user-provided code. For this `PDAF_iau_set_pointer` can be used to assess the increment array within PDAF.