Developing Intensity-Duration-Frequency (IDF) curves using GPM-IMERG v6
data: A Case Study from South India
Abstract
With the availability of satellite-based precipitation products, it is
pertinent to develop methods to use these data products for the purpose
of design of hydraulic structures. The satellite precipitation products
play a vital role in ungauged locations or when information is required
a catchment scale. Prior to such applications, the accuracy and
uncertainty associated with the products have to be investigated. This
study compares Intensity Duration Frequency (IDF) curves using the
recent precipitation product Global Precipitation Measurement (GPM-IMERG
V6) with ground-based gauge data over the southeastern part of India and
quantifies the uncertainty associated. Further, for comparison, a
bias-corrected dataset is used in the study to understand the
implication of bias correction of the satellite product in the IDF
generation. The spatial correlation between the satellite IDF and the
gauge-based IDF improves significantly after bias correction and the
value is as high as 0.75 for 2- 10 year return period. The bias between
the satellite IDF and gauge IDF is low in the north part of the study
region and is high in the southeastern part, prone to extreme rainfall.
Further, a significant percentage of the satellite-based IDFs (with and
without bias correction) lie inside the confidence interval of the
gauge-based data.