Uncertainty of measurement for a given pollutant
unc_year.Rd
Compute measurement uncertainty for time series of a given pollutant.
Arguments
- obs
A numeric vector, data.frame or data.table of observed concentration data.
- alpha
Non-proportional fraction factor (0 <= a <= 1). Default value = 0.20 (for NO_2).
- RV
Reference value. Default value = 200 (for NO_2).
- U_RV
Standard measurement uncertainty around the RV. Default value = 0.24 (for NO_2).
- Np
Parameter to account for the compensation of errors. Default value = 5.2 (for NO_2).
- Nnp
Parameter to account for the compensation of errors. Default value = 5.5 (for NO_2).
- ...
Optional parameters passed to mean, such as
na.rm = TRUE
.
Details
The function computes the 95th percentile uncertainty for yearly averaged measurement, as described in Annex 1 of Janssen et al., FAIRMODE Guidance Document on Modelling Quality Objectives and Benchmarking (Fairmode MQO Guidance V3.2): $$ U(\bar{O}) \approx U_r(RV) \sqrt{\frac{1 - \alpha^2}{N_p} \bar{O}^2 + \frac{\alpha^2 \cdot RV^2}{N_{np}}} $$
The values of the parameters for various pollutants are reported in Table 6 of the Fairmode MQO Guidance.