Creating a retrospective run

Creating a retrospective run with or without routing

Problem

You need to create a new retrospective run. There can be a number of reasons for this, for example

• new nowcast/forecast project
• new or updated meteorological forcings
• change in retrospective period

Method

A long-term retrospective run is typically performed in the following way:

• The hydrological model is run with a cold start for the full retrospective period for which meteorological forcings are available (e.g. 1915-01-01 through 2005-12-31)
• The model state from the end of the run is recycled and use to restart at the beginning of the run (e.g. the state file from 2005-12-31 is used to start on 1915-01-01)
• The model is then run for one year (e.g. 1915-01-01 through 1915-12-31)
• The state file from the end of the run is again recycled to restart at the beginning of the run (e.g. the state file from 1915-12-31 is used to start on 1915-01-01)
• The previous two steps are repeated 10 times
• The model is then restarted one final time and allowed to run through the end of the retrospective period (e.g. 1915-01-01 through 2005-12-31)
• If routing is enabled, the flows from the final simulation are routed
• The first year is discarded from any further analysis

Script(s) to run

create_retro_run.pl

Expected outcome(s)

PATHS NEED UPDATING

• The control file for the final run will be in <CONTROL_DIR>
• Output files for a long-term model run will be stored in <RESULTS_RETRO_DIR>. Any intermediate files created during the runs will also be created in this directed, but will be overwritten in the final run.
• The state files for the start and the end of the run will be stored in <STATE_RETRO_DIR>. The intermediate state files are deleted to avoid confusion.
• If routing is enabled, then the routed flows will be in <>