Normalization

The Eq. 3 primitive shared by every test.

The Eq. 3 normalization primitive used by every DEBRA test.

shachen.norm.normalize(x, bounds: Bounds)

N(x) = clip((x - MIN) / (MAX - MIN), 0, 1) (Miller et al. 2017, Eq. 3).

Works on scalars, numpy arrays, and xarray DataArrays. bounds.min may exceed bounds.max (used for the cos-zenith blends specified in zenith-angle space): the sense of the ramp reverses.

shachen.norm.normalize_interp(x, day: Bounds, ngt: Bounds, weight)

N(x) with the interval linearly interpolated between two sets.

weight is per-pixel and selects day at 1, ngt at 0. Used for the Eq. 19 normalization of the terminator confidence factor, whose raw ceiling sits between the day and night ones; the weight is Eq. 20’s B_ngt_trm, so CF_trm is on the day scale where Eq. 22 blends it into CF_day and on the night scale where it blends into CF_ngt.

shachen.norm.normalize_cos_zenith(zenith_deg, zenith_bounds_deg: Bounds, exponent: float)

N(cos(theta); cos(MIN_deg), cos(MAX_deg)) ** exponent (Eqs. 20-21, 25).