Precipitation change indicator: data sources and methods, chapter 5

5. Caveats and limitations

Breaks in the data can be a concern. To mitigate this, the Precipitation Change in Canada indicator uses homogenized and adjusted station data for precipitation. These data have been adjusted to account for discontinuities in the data from non-climatic factors, such as changes in observation methods, equipment or station location. Observations from nearby co-located stations are sometimes merged to produce longer time series.

A given variation in the amount of precipitation for a station with low normal precipitation will result in a much larger departure then for a station with high normal precipitation. This is due to precipitation amounts at monitoring stations being normalized against their respective reference value in the calculation of the national departure.