Parameter

Meaning

full data

before 1991

after 1994

(unit)

A

Expon. trend

50.1

18.2

49.0

(ppm)

t₀

Expon. time constant

61.69

32.32

60.81

(year)

B

Sine amplitude

2.85

2.75

2.96

(ppm)

C

Base line

256.4

291.2

257.3

(ppm)

φ₀

Sine phase

−0.368

−0.410

−0.311

(rad)