3. Deal with errors

OGGM will not be able to run on a number of glaciers. We summarized the reasons for this in our GMD publication and showed that the number of failing glaciers can be quite high depending on the region considered.

In this example, we run the model on a list of three glaciers: two of them will end with errors: one because it already failed at preprocessing (i.e. prior to this run), and one will fail during the run.

Script

The important part of the script is the set-up of the continue_on_error global parameter to True. This will allow OGGM to continue the run despite of some glaciers having errors, a useful feature for regional or global applications.

# Python imports
import logging

# Locals
import oggm.cfg as cfg
from oggm import utils, workflow, tasks

# For timing the run
import time
start = time.time()

# Module logger
log = logging.getLogger(__name__)

# Initialize OGGM and set up the default run parameters
cfg.initialize(logging_level='WORKFLOW')

# Here we override some of the default parameters
# How many grid points around the glacier?
# We make it small because we want the model to error because
# of flowing out of the domain
cfg.PARAMS['border'] = 80

# This is the important bit!
# We tell OGGM to continue despite of errors
cfg.PARAMS['continue_on_error'] = True

# Local working directory (where OGGM will write its output)
WORKING_DIR = utils.gettempdir('OGGM_Errors')
utils.mkdir(WORKING_DIR, reset=True)
cfg.PATHS['working_dir'] = WORKING_DIR

rgi_ids = ['RGI60-11.00897', 'RGI60-11.01450', 'RGI60-11.03295']

log.workflow('Starting OGGM run')
log.workflow('Number of glaciers: {}'.format(len(rgi_ids)))

# Go - get the pre-processed glacier directories
gdirs = workflow.init_glacier_directories(rgi_ids, from_prepro_level=4)

# We can step directly to the experiment!
# Random climate representative for the recent climate (1985-2015)
# with a negative bias added to the random temperature series
workflow.execute_entity_task(tasks.run_random_climate, gdirs,
                             nyears=150, seed=0,
                             temperature_bias=-1)

# Write the compiled output
utils.compile_glacier_statistics(gdirs)
utils.compile_run_output(gdirs)

# Log
m, s = divmod(time.time() - start, 60)
h, m = divmod(m, 60)
log.workflow('OGGM is done! Time needed: %d:%02d:%02d' % (h, m, s))

If everything went “well”, you should see an output similar to:

2020-03-24 18:54:32: oggm.cfg: Using configuration file: /home/mowglie/disk/Dropbox/HomeDocs/git/oggm-fork/oggm/params.cfg
2020-03-24 18:54:32: oggm.cfg: Multiprocessing switched ON according to the parameter file.
2020-03-24 18:54:32: oggm.cfg: Multiprocessing: using all available processors (N=8)
2020-03-24 18:54:32: __main__: Starting OGGM run
2020-03-24 18:54:32: __main__: Number of glaciers: 3
2020-03-24 18:54:32: oggm.workflow: init_glacier_directories from prepro level 4 on 3 glaciers.
2020-03-24 18:54:32: oggm.workflow: Execute entity task gdir_from_prepro on 3 glaciers
2020-03-24 18:54:32: oggm.workflow: Initializing multiprocessing pool with N=8 processes.
2020-03-24 18:55:00: oggm.workflow: Execute entity task run_random_climate on 3 glaciers
2020-03-24 18:55:00: oggm.core.flowline: RuntimeError occurred during task run_random_climate on RGI60-11.03295: Need a valid `model_flowlines` file. If you explicitly want to use `inversion_flowlines`, set use_inversion_flowlines=True.
2020-03-24 18:55:10: oggm.core.flowline: RuntimeError occurred during task run_random_climate on RGI60-11.00897: Glacier exceeds domain boundaries, at year: 135.83333333333334
2020-03-24 18:55:31: oggm.workflow: Execute entity task glacier_statistics on 3 glaciers
2020-03-24 18:55:31: __main__: OGGM is done! Time needed: 0:00:59

Dealing with errors

The simplest way to deal with errors is to look for NaNS (“not a number”) in the run_output*.nc files: glaciers with errors will have NaNs in place of their timeseries. For an in-depth analysis of the cause of these errors, OGGM delivers some tools to help you out. We have prepared two notebooks to show you their usage:

  • deal_with_errors.ipynb builds upon the example above to analyse the output
  • preprocessing_errors.ipynb reproduces the error analysis of our GMD paper

You can open these tutorials online by following this link:

https://img.shields.io/badge/Launch-OGGM%20tutorials-579ACA.svg?style=popout&logo=data:image/png;base64,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