sup3r.bias.mixins.ZeroRateMixin

class ZeroRateMixin

Bases: object

Estimate zero rate

[Pierce2015].

References

[Pierce2015] (1,2,3)

Pierce, D. W., Cayan, D. R., Maurer, E. P., Abatzoglou, J. T., & Hegewisch, K. C. (2015). Improved bias correction techniques for hydrological simulations of climate change. Journal of Hydrometeorology, 16(6), 2421-2442.

Methods

zero_precipitation_rate(arr[, threshold])

Rate of (nearly) zero precipitation days

static zero_precipitation_rate(arr: ndarray, threshold: float = 0.0)

Rate of (nearly) zero precipitation days

Estimate the rate of values less than a given threshold. In concept the threshold would be zero (thus the name zero precipitation rate) but it is often used a small threshold to truncate negligible values. For instance, [Pierce2015] uses 0.01 mm/day for PresRat correction.

Parameters:

• arr (np.ndarray) – An array of values to be analyzed. Usually precipitation but it could be applied to other quantities.

• threshold (float) – Minimum value accepted. Less than that is assumed to be zero.

Returns:

rate (float) – Rate of days with negligible precipitation (see Z_gf in [Pierce2015]).

Notes

The NaN are ignored for the rate estimate. Therefore, a large number of NaN might compromise the confidence of the estimator.

If the input values are all non-finite, it returns NaN.

Examples

>>> ZeroRateMixin().zero_precipitation_rate([2, 3, 4], 1)
0.0

>>> ZeroRateMixin().zero_precipitation_rate([0, 1, 2, 3], 1)
0.25

>>> ZeroRateMixin().zero_precipitation_rate([0, 1, 2, 3, np.nan], 1)
0.25