RmarineHeatWaves {RmarineHeatWaves}

RmarineHeatWaves.

Description

This package is an R implementation of the python script marineHeatWaves (https://github.com/ecjoliver/marineHeatWaves) written by Eric C. J. Oliver as part of the marine heat waves definition by Hobday et al. (2016).

Details

Although the title of the package refers to marine heat waves (MHW), it is equally capable of detecting marine cold spells (MCS). This functionality to detect cold events is also present in the python package, where it was implemented as a result of the publication Schlegel et al. (2017) that discusses the quantification and detection of anomalously cold events. As of release 0.16.0, the detect function may also be applied to time series of other natural phenomena which one might want to express in terms of the summary metrics outlined in the paper by Hobday et al. (2016).

The main function is the detection function detect which takes as input a time series of temperature (and a corresponding series of dates) and outputs a set of detected MHWs or MCS, as well as the climatological (varying by day-of-year) seasonal cycle and extremes threshold. There are various helper functions to fascilitate developing an uninterrupted time series of temperatures (e.g. make_whole) and some options to produce graphical summaries and representations of the detected events such as event_line and lolli_plot, or the ggplot2 equivalents, geom_flame and geom_lolli.

This package is demonstrated by applying the MHW definition to observed SST records and showing how it identifies three historical MHWs: the 2011 Western Australia event, the 2012 Northwest Atlantic event and the 2003 Mediterranean event. These data are included herewith.

One may also use the exceedance function to calculate consecutive days above or below a given static threshold. The output of this function is similar to detect.

Author(s)

Albertus J. Smit <[e-mail]>, Robert W. Schlegel, Eric C. J. Oliver

References

Hobday, A. J. et al. (2016), A hierarchical approach to defining marine heatwaves. Progress in Oceanography, 141, pp. 227-238, <DOI:10.1016/j.pocean.2015.12.014> (official citation for this package).

Schlegel, R. W., Oliver, E. C. J., Wernberg, T. W., Smit, A. J. (2017) Coastal and offshore co-occurrences of marine heatwaves and cold-spells. Progress in Oceanography, 151, pp. 189-205, <DOI:10.1016/j.pocean.2017.01.004>