flagGRDCoutliers: Flag GRDC outliers
In messamat/globalIRmap: What the Package Does (One Line, Title Case)

Description Usage Arguments Details Value Source

Flag potential outliers in daily discharge records for a given GRDC gauging station following the criteria developed for GSIM by Gudmundsson et al. (2018).

1	flagGRDCoutliers(in_gaugetab)

in_gaugetab

data.table containing formatted daily discharge record from GRDC gauging station (as formatted by readformatGRDC.

Criteria to flag a daily discharge value (Qt) as a potential outlier include:

Negative values (Qt < 0)
At least ten identical consecutive discharge values (for Qt > 0)
|log(Qt + 0.01) - mean| are larger than the mean values of log(Q + 0.01) plus or minus 6 times the standard deviation of log(Q + 0.01) computed for that calendar day for the entire length of the series. The mean and SD are computed for a 5-day window centred on the calendar day to ensure that a sufficient amount of data is considered. The log-transformation is used to account for the skewness of the distribution of daily streamflow values.
Qt for which Original != Calculated discharge in GRDC record

data.table of daily discharge records with additional columns for outlier flags

Gudmundsson, L., Do, H. X., Leonard, M., & Westra, S. (2018). The Global Streamflow Indices and Metadata Archive (GSIM) – Part 2: Quality control, time-series indices and homogeneity assessment. Earth System Science Data, 10(2), 787–804. https://doi.org/10.5194/essd-10-787-2018

messamat/globalIRmap documentation built on July 4, 2021, 10:48 a.m.