Evaluation and Correction of GPM IMERG Precipitation Products over the Capital Circle in Northeast China at Multiple Spatiotemporal Scales

Table 2

List of the statistical metrics used in the evaluation.

Statistic metrics	Equation	Optimum value
Mean (M)	;	NA
Correlation coefficient (CC)		1
NRMSE		0
RMSE		0
BIAS		0
NSE		1
Underreporting rate (UR)		0
False alarm ratio (FAR)		0
Critical success index (CSI)		1

Note: n represents number of samples; represents the satellite precipitation estimate; represents the gauge observed precipitation; Cov() represents the covariance; represents standard deviations of gauge precipitation; represents standard deviations of satellite precipitation; represents the precipitation observed by the gauge and satellite simultaneously; represents the precipitation observed by the gauge but not observed by the satellite; is contrary to ; and represents the precipitation observed neither by the gauge nor the satellite.