Research papersDeveloping intensity duration frequency curves based on scaling theory using linear probability weighted moments: A case study from India

- The scaling characteristics of rainfall in India is investigated.
- Using the scaling laws or relationships, IDF curves were derived at high temporal resolution.
- The results show that the method based on scaling relationships were very useful in urban hydrology.

In this study, presence of multi-scale behaviour in rainfall IDF relationship has been established using Linear Probability Weighted Moments (LPWMs) for some selected stations in India. Simple, non-central moments (SMs) have seen widespread use in similar scaling studies but these latter statistical attributes are known to mask the 'true' scaling pattern and, consequently, leading to inappropriate inferences. There is a general agreement amongst researchers that conventional higher order moments do indeed amplify the extreme observations and drastically affect scaling exponents. Additional advantage of LPWMs over SMs is that they exist even when the standard moments do not exist. As an alternative, this study presents a comparison with results based on use of the robust LPWMs which have revealed, in sharp contrast with the conventional moments, a definitive multi-scaling behaviour in all four rainfall observation stations that were selected from different climatic zones. The multi-scale IDF curves derived using LPWMs show a good agreement with observations and it is accordingly concluded that LPWMs provide a more reliable tool for investigating scaling in sequences of observed rainfall corresponding to various durations.