Double mass analysis
 |
This article has multiple issues. Please help improve it or discuss these issues on the talk page.
|
Double mass analysis [1] is a commonly used data analysis approach for investigating the behaviour of records made of hydrological or meteorological data at a number of locations. It is used to determine whether there is a need for corrections to the data to account for changes in data collection procedures or other local conditions. Such changes may result from a variety of things including changes in instrumentation, changes in observation procedures, or changes in gauge location or surrounding conditions. Double mass analysis for checking consistency of a hydrological or meteorological record is considered to be an essential tool before taking it for analysis purpose.
An example of a double mass analysis is a "double mass plot", or "double mass curve".[2] For this, points and/or a joining line are plotted where the x- and y- coordinates are determined by the running totals of the values observed at two stations. If both stations are affected to the same extent by the same trends then a double mass curve should follow a straight line. A break in the slope of the curve would indicate that conditions have changed at one location but not at another.
[edit] Notes
- ^ Searcy, J.K. and C.H. Hardison (1960). Double-mass curves. U.S. Geological Survey Water-Supply Paper 1541-B'
- ^ Wilson, E.M. (1983) Engineering Hydrology, 3rd edition. Macmillan Press, London. p.27
[edit] Further reading
- Dubreuil P. (1974). "Initiation à l'analyse hydrologique". Masson& Cie et ORSTOM, Paris.
