Get_flood_metrics: Get_flood_metrics

In sarahforte/CESIfun: Calculating flood and drought metrics, executing trend tests using specific parameters

Description

Get_flood_metrics takes in a character representing the station number within 1014 RHBN_U stations and a vector of numerics or a character, calculates four flood metrics: pot_threshold: the upper threshold that was calculated in Threshold_build function from above; pot_days:days over the threshold within a year; pot_events:independent flood events over a year; pot_ma_dur: the maximum consecutive duration over the threshold within a year; The four metrics will then be recorded in a table and returned.

Usage

Get_flood_metrics(station, year = "all")

Arguments

station	a character representing a station we want the flood metrics to be calculated at;
year	a vector of numeric representing the list of years we want thew flood metrics to be calculated at, defaulted to 'all' indicating all the years at the station;

Details

Note that there are requirements regarding the independence conditions for pot_event metric, we implement a check for the correlation between flood events. Referring to Lang etal (1999), we set two conditions: 1) R > 5+log(A/1.609^2); 2) Xmin < 0.75 * min(Xi, Xj); where R is the time in days between two peaks, A is the watershed area in squared kilometers; Xmin is the minimum flow between the adjacent flow peaks Xi and Xj. In order for two seperate peaks to be considered as independent events of drought or flood, both conditions need to be met. If either of the conditions fail, we consider two events as the same one. R is defined within the iteration.

Value

A dataframe of the format: || STATION_NUMBER || Year || pot_days || pot_events || pot_threshold || pot_max_dur ||

References

Slater et al.(2016). On the impact of gaps on trend detection un extreme streamflow time series. Int.J.climatol. 37:3976-3983(2017). doi: 10.1002/joc.4954

sarahforte/CESIfun documentation built on Dec. 22, 2021, 10:16 p.m.