Description Usage Arguments Details Value Examples

View source: R/calculate_stats.R

`CalcFdcPerf`

calculates flow duration curve statistics for streamflow
output.

1 2 | ```
CalcFdcPerf(strDf.mod, strDf.obs, strCol.mod = "q_cms",
strCol.obs = "q_cms", stdate = NULL, enddate = NULL)
``` |

`strDf.mod` |
The forecast point output dataframe (required). Assumes only one forecast point per file, so if you have multiple forecast points in your output dataframe, use subset to isolate a single forecast point's data. Also assumes model output and observation both contain POSIXct fields (called "POSIXct"). |

`strDf.obs` |
The observed streamflow dataframe. Assumes only one gage per file, so if you have multiple gages in your dataframe, use subset to isolate a single gage's data. Also assumes model output and observation both contain POSIXct fields (called "POSIXct"). |

`strCol.mod` |
The column name for the streamflow time series for the MODEL data (default="q_cms") |

`strCol.obs` |
The column name for the streamflow time series for the OBSERVED data (default="q_cms") |

`stdate` |
Start date for statistics (DEFAULT=NULL, all records will be used). Date MUST be specified in POSIXct format with appropriate timezone (e.g., as.POSIXct("2013-05-01 00:00:00", format="%Y-%m-%d %H:%M:%S", tz="UTC")) |

`enddate` |
End date for statistics (DEFAULT=NULL, all records will be used). Date MUST be specified in POSIXct format with appropriate timezone (e.g., as.POSIXct("2013-05-01 00:00:00", format="%Y-%m-%d %H:%M:%S", tz="UTC")) |

`CalcFdcPerf`

reads a model forecast point streamflow timeseries (i.e.,
created using `ReadFrxstPts`

) and a streamflow observation
timeseries (i.e., created using `ReadUsgsGage`

) and calculates
flow duration curve statistics at various exceedance thresholds (e.g., 10%,
20%, etc.). The tool will subset data to matching time periods (e.g., if the
observed data is at 5-min increments and modelled data is at 1-hr increments,
the tool will subset the observed data to select only observations on the
matching hour break).

Flow Duration Curve Statistics:

(mod = model output, obs = observations)

p.exceed: exceedance threshold (e.g., 0.2 means a flow value that is exceeded 20% of the time)

q.mod: MODEL flow value at specified exceedance threshold (in native flow units)

q.obs: OBSERVED flow value at specified exceedance threshold (in native flow units)

q.err: difference between model and observed flow values [mod-obs] (in native flow units)

q.perr: percent error in model flow [(mod-obs)/obs]

A new dataframe containing the flow duration curve statistics.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 | ```
## Take forecast point model output for Fourmile Creek (modStrh.mod1.fc)
## and a corresponding USGS gage observation file (obsStrh.fc), both at an
## hourly time step, and calculate flow duration curve statistics. The
## model forecast point data was imported using ReadFrxstPts and the gage
## observation data was imported using ReadUsgsGage.
## Not run:
CalcFdcPerf(modStr1h.allrt.fc, obsStr5min.fc)
Output:
p.exceed q.mod q.obs
0.1 3.07 5.25
0.2 1.35 2.31
0.3 0.82 1.06
0.4 0.48 0.65
0.5 0.29 0.45
0.6 0.18 0.34
0.7 0.14 0.25
0.8 0.11 0.19
0.9 0.08 0.16
## End(Not run)
``` |

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