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Module clim_oggm

The clim_oggm module processes monthly historical climate data from the GSWP3_W5E5 dataset, obtained via the oggm_shop module. It generates monthly 2D raster fields for corrected precipitation, mean temperature, and temperature variability. The module applies a multiplicative correction factor to precipitation (prcp_fac) and a bias correction to temperature (temp_bias). Temperature data is extrapolated across the glacier surface using a reference height and a constant lapse rate (temp_default_gradient). In contrast, precipitation and temperature variability data are distributed across the entire domain without additional corrections. All necessary calibrated parameters are provided by the oggm_shop module. These outputs are intended for use in surface mass balance or enthalpy modeling.

The module also supports generating climate data beyond the observational time frame. This is achieved by defining a reference period (ref_period) to randomly select years within this interval (typically a climate-neutral period). A temperature bias and a precipitation scaling are then applied. These parameters can be specified in a file (file parameter), as shown in the example below. The example illustrates a linear temperature increase of 4 degrees by 2100 (relative to the 1960–1990 period):

time   delta_temp  prec_scal
1900          0.0        1.0
2020          0.0        1.0
2100          4.0        1.0

If the clim_trend_array parameter is set to an empty list ([]), the module reads the data from the specified file. Otherwise, it uses the clim_trend_array parameter, which must be a list of lists.

Contributors: Guillaume Jouvet, Fabien Maussion

Config Structure

clim_oggm:
  update_freq: 1
  file: file.txt
  clim_trend_array:
    - ["time", "delta_temp", "prec_scal"]
    - [1900, 0.0, 1.0]
    - [2020, 0.0, 1.0]
  ref_period: [1960, 1990]
  seed_par: 123

Parameters

Here we store a table with

Name Type Units Description Default Value
update_freq float y Update the climate each X years 1
file string dimless Name of the input file for the climate outside the given datetime frame (time, delta_temp, prec_scaling) file.txt
clim_trend_array list dimless Define climate trend outside available time window [['time', 'delta_temp', 'prec_scal'], [1900, 0.0, 1.0], [2020, 0.0, 1.0]]
ref_period list dimless Define the reference period to pick year outside available time window [1960, 1990]
seed_par integer dimless Seeding parameter to fix for picking randomly year in the ref period 123

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