verification (version 1.01)

verify: Verification function

Description

Based on the type of inputs, this function calculates a range of verification statistics and skill scores. Additionally, it creates a verify class object that can be further analyzed.

Usage

verify(obs, pred,  tseries= NULL, baseline = NULL,           frcst.type = "prob", obs.type = "binary",  thresholds = seq(0,1,0.1) )

Arguments

obs

The value with which the verifications are verified.

pred

Prediction of event. The prediction may be in the form of the a point prediction or the probability of a forecast.

tseries

Optional time series vector. This allows certain types of plots to be made.

baseline

In meteorology, climatology is the baseline that represents the no-skill forecast. In other fields this field would differ. This field is used to calculate certain skill scores. If left NULL, these statistics are calculated using sa

frcst.type

Forecast type. Either "prob", "binary", or "cont". Defaults to "prob"

obs.type

Observation type. Either "binary", or "cont". Defaults to "binary"

thresholds

Thresholds to be considered for point forecasts of continuous events.

Value

• An object of the verify class. Depending on the type of data used, the following information may be returned. The following notation is used to describe which values are produced for which type of forecast/observations. (BB = binary/binary, PB = probablistic/binary, CC = continuous/continuous.)
• BS
  Brier Score (PB)
• BSS
  Brier Skill Score(PB)
• SS
  Skill Score (BB)
• hit.rate
  Hit rate, aka PODy, $h$ (PB)
• false.alarm.rate
  False alarm rate, PODn, $f$ (PB)
• TS
  Threat Score or Critical Success Index (CSI)(BB)
• ETS
  Equitable Threat Score (BB)
• BIAS
  Bias (BB)
• PC
  Percent correct or hit rate (BB)
• Cont.Table
  Contingency Table (BB)
• HSS
  Heidke Skill Score(BB)
• KSS
  Kuniper Skill Score (BB)
• ME
  Mean error (CC)
• MSE
  Mean-squared error (CC)
• MAE
  Mean absolute error (CC)

References

Wilks, D. S. (1995) Statistical Methods in the Atmospheric Sciences Chapter 7, San Diego: Academic Press.

WMO Joint WWRP/WGNE Working Group on Verification Website http://www.bom.gov.au/bmrc/wefor/staff/eee/verif/verif_web_page.html

World Meteorological Organization Verification Website http://www.wmo.ch/web/aom/pwsp/Verification.html

Examples

# binary/binary example
obs<- round(runif(100))
pred<- round(runif(100))

A<- verify(obs, pred, frcst.type = "binary", obs.type = "binary")
summary(A)
#  probabilistic/ binary example
pred<- runif(100)
A<- verify(obs, pred, frcst.type = "prob", obs.type = "binary")
summary(A)
# continuous/ continuous example
obs<- rnorm(100)
pred<- rnorm(100)
baseline <- rnorm(100, sd = 0.5) 

A<- verify(obs, pred, baseline = baseline,  frcst.type = "cont", obs.type = "cont")
summary(A)