Python Package for the Analysis of Precipitation Seasonality

Annual cycles of wet and dry periods are an important feature of the seasonal climate in many areas of the world, including North America. Some regions of North America, like the Great Plains, have well defined wet and dry seasons while other areas, like the U.S. southeast, have multiple or even continuous wet seasons. These seasonal oscillations, much like temperature, can change in any combination of amplitude, periodicity or phase. Alterations to these seasonal parameters can have a tremendous effect on water resources and agriculture, and interact with other extremes such as wildfires and droughts.

Previous investigations into precipitation seasonality have primarily used two types of algorithms to determine the wet and dry season onset and cessation dates. The first class of methods for onset and cessation use threshold values, such as the number of days above or below a daily precipitation amount. The chosen threshold values are regionally specific to study areas or phenomena, such as the Indian Monsoon. The second class of methods generally use some form of cumulative precipitation anomalies to determine the onset and cessation dates.

Our python module contains a collection of these algorithms and other helpful utilities that enables easier analysis of wet and dry seasons. Using multiple algorithms for seasonality can allow for a more detailed analysis of seasonality from the local to regional scope. Analysis using the algorithms will be presented along with an overview of module details.