The Constructor

Analysis and Presentation of Rainfall Data

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Analysis of Rainfall Data

Before using rainfall records at a station for any analysis, the data has to be checked for Missing rainfall data can be estimated using the rainfall data at neighbouring stations.

Estimation of Missing Rainfall Data

Required to find the missing annual precipitation at station X (not included in the m neighbouring stations), given the annual precipitation values at m neighbouring raingauge stations . Let the normal annual precipitation at the m+1 stations be If the normal precipitations at the different stations are within 10% of the normal annual precipitation at station X, then If the normal precipitation at any of the m stations vary by more than 10% from the normal annual precipitation at station X, then is estimated by the normal ratio method as

Test for Consistency of Record

Inconsistency would arise in the rainfall data at a raingauge station if conditions relevant to recording of rainfall at the station undergoes significant change during the period of record. It would be felt from the time a significant change took place. Some common causes for inconsistency of record Check for inconsistency of record is done by the double mass curve technique (based on the principle that when each recorded data comes to same parent population, they will be consistent.

Figure: Double mass curve

Thus older records are brought to the new regime at X.

Presentation of Rainfall Data

Mass Curve of Rainfall

Figure: Mass curve of rainfall


Figure: Hyetograph of a storm

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