Near Future Typicality for precipitation wettest quarter

Typicality quantifies climate change relative to historical climate variability. For a given climate variable, we define near future climate change as the difference between the future mean (2011-2040) and a mid-20th century baseline mean (1948-1980). This is referred to as a “delta”. We define climate variability as the deviation around the baseline mean, measured by taking the difference between the baseline mean and the value for each individual year in the baseline. These are called “anomalies”. To calculate typicality, for each 800m pixel across the study area, we compute the proportion of baseline anomalies that are greater than the current delta. This produces an index between 0 and 1 that measures the degree to which the current delta falls within historical levels of variability. A typicality value of 1 results when the current delta isn’t more extreme than any of the baseline anomalies, indicating “typical” climate conditions. A typicality of 0 results when the delta is larger than every anomaly in the baseline, indicating “novel” climate conditions. A typicality value of 0.25 would indicate that current delta is more extreme than 75% of the anomalies that occurred across all the baseline years.