Rainfall double-mass selected-split slopes calculator

Calculate early cumulative slope and late cumulative slope with your own figures.

Your numbers

Use the units shown. Results update as you change valid inputs.

Use early cumulative slope and late cumulative slope to compare changes to your inputs. The method and limits below explain the scope.

Examples

Examples

Try the starting example

Station rainfall by period (mm)
20,30,40,20,25,30
Reference rainfall by same period (mm)
20,30,40,40,50,60
Candidate split after period (count)
3
Early cumulative slope
1
Late cumulative slope
0.5
Late/early slope ratio
0.5
Cumulative reference/station pairs (JSON)
[[20,20],[50,50],[90,90],[130,110],[180,135],[240,165]]

Try another scenario

Station rainfall by period (mm)
[21, 30, 40, 20, 25, 30]
Reference rainfall by same period (mm)
[20, 30, 40, 40, 50, 60]
Candidate split after period (count)
3
Early cumulative slope
1.011111
Late cumulative slope
0.5
Late/early slope ratio
0.494505
Cumulative reference/station pairs (JSON)
[[20,21],[50,51],[90,91],[130,111],[180,136],[240,166]]
Calculation method

Calculation method

Early cumulative slope

Compare through-increment mass slopes before and after a user-selected split; this diagnostic does not establish a causal station change.

Late cumulative slope

Compare through-increment mass slopes before and after a user-selected split; this diagnostic does not establish a causal station change.

Late/early slope ratio

Compare through-increment mass slopes before and after a user-selected split; this diagnostic does not establish a causal station change.

Cumulative reference/station pairs (JSON)

Compare through-increment mass slopes before and after a user-selected split; this diagnostic does not establish a causal station change.

Symbols and units
a
Station rainfall by period (mm)
b
Reference rainfall by same period (mm)
c
Candidate split after period (count)

Use the units shown. A list keeps the order in which you enter its values. The symbol ^ means “raised to the power of”.

Assumptions & limits

Assumptions & limits

  • User-supplied measurements and assumptions; Compare through-increment mass slopes before and after a user-selected split; this diagnostic does not establish a causal station change. Supported limits: Finite numeric values bounded to 1e9 magnitude; lists and tables contain 1–100 records unless a stricter bound is stated. Inputs use the units shown. Lists explicitly paired by a method must have matching lengths; independent polynomial coefficient vectors may differ. Respect stated physical, interpolation, policy and computational domain limits.
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Further reading

Method reference ↗

Background reading; this does not imply endorsement or independent review of SumFizz.

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