The AssimInfo.txt file contains additional model settings to info.txt and is therefore located in the same folder as info.txt. If assimilation is switched on (assimilation Y) in info.txt, the AssimInfo.txt file is used to define what kind of data assimilation is to be performed. The file information is divided into four groups:

1. general settings,
2. setting of control variables,
3. observation settings, and
4. meteorological forcing data settings.

The settings are usually kept in their four groups, but that is not necessary. The general settings all start with the letters G_, while the control variable settings start with A_, observations settings with O_ and forcing settings with F_. The control variable settings determine the group of HYPE states to which the filtering is applied.

The basic format in the AssimInfo.txt file is simply a row-wise combination of codes and argument(s):

!! <comment>
<code 1.1> [<code 1.2>] <argument 1> [<argument 2>] ... [<argument n>] 
<code 2.1> [<code 2.2>] <argument 1> [<argument 2>] ... [<argument m>] 
...

Comment rows can be added anywhere and are marked with double exclamation marks, i.e. !!, or '!!' followed by a space. For other rows, the first code string decides what information is to be read. The code can be written within or without apostrophes ('…'). Codes are not case sensitive. Maximum 18000 characters can be read on a single line.

These are the variables controlled by assimilation. They are set as a group by category or separate by name. The categories and names are specific to the HYPE model. If they are turned off, the analysis is NOT applied to variables in this category. Instead, they are re-initialized to the ensemble mean (or median depending on G_MEANOUT) after each time step. If they are turned on, the analysis IS APPLIED whenever there are observations available. No re-initialization.

Format of control variable lines: They start with A_ followed by include_ or exclude_ followed by bycategory or byname followed by [category] or [name]. To identify the variable by name, the category of the variable need to be set on a line directly before the variable. Example:

A_INCLUDE_BYCATEGORY SNOW 
A_INCLUDE_BYCATEGORY SOIL 
A_EXCLUDE_BYCATEGORY GLACIER 

The observation settings determine which observations should be assimilated. The observations settings are given as a table with one observation variable per line. The settings include which HYPE outvar variables to compare, the ensemble generation model, minimum and maximum values allowed, standard deviation parameters, and parameters for generation of spatially correlated perturbations. The columns are in the order given in the table below.

The meterological forcing data settings determine which forcing data should be perturbed and included in assimilation. The settings are given as a table with one forcing variable per line. The settings include the ensemble generation model, minimum and maximum values allowed, standard deviation parameters, and parameters for generation of spatially correlated perturbations. The columns are in the order given in the table below.