m9brady / cis-historical-date

Estimating standardized dates for historical Canadian Ice Service regional ice charts

Canadian Ice Service (CIS) Historical Dates

In recent years, regional ice analysis charts produced by the CIS are generated on a regular basis and are said to be valid for Monday of a given week [1]. However, charts produced in years prior did not have this regular schedule so one way to introduce standardization is to use a fixed "Historical Date" to enable climatological (long-term) analysis.

This Python code repository attempts to estimate the HIST_DATE given a chart-issuance date with zero third-party dependencies.

To learn more about the charts produced by the CIS, go to https://www.canada.ca/en/environment-climate-change/services/ice-forecasts-observations/latest-conditions/products-guides/chart-descriptions.html

How-To

0. Ensure you have Python installed and available for use

1. Download the repository:

git clone https://github.com/m9brady/cis-historical-date
cd cis-historical-date

2. Run the examples:

python example.py
chart_date: 20150302 --> hist_date: 0305
chart_date: 19780713 --> hist_date: 0716
chart_date: 20120301 --> hist_date: 0226
chart_date: 19951231 --> hist_date: 0101

3. Use the function interactively:

>>> from cis import calc_historical_date
>>> calc_historical_date('20140901')
'0903'

References

[1] https://www.canada.ca/en/environment-climate-change/services/ice-forecasts-observations/latest-conditions/products-guides/chart-descriptions.html#weekly_ice