DEVELOPMENT OF INTENSITY DURATION FREQUENCY CURVES USING TRMM PRECIPITATION DATA
Intensity–duration–frequency (IDF) relationship of rainfall amounts is one of the most commonly used tools in water resources engineering for planning, design and operation of water resources projects. The objective of this research is to derive IDF relationship of rainfall using TRMM data. The Tropical Rainfall Measuring Mission (TRMM) is a joint mission of NASA and JAXA (Japan Aerospace Exploration Agency) to study rainfall for weather and climate research. The IDF relationships are useful in the design of urban drainage works, e.g. storm sewers, culverts and other hydraulic structures. In poorly instrumented areas, rainfall records are often absent or short, compounding the statistical challenge of estimating extreme rainfall characteristics and designing flood control structures. The TRMM data which generally give the precipitation amount are processed to get the rainfall intensity at desired intervals such as 6 hours, 12 hours etc. for preparing an annual maximum data series. Gumbel's distribution is used for obtaining max rainfall intensity for a given duration having a particular return period. The data so obtained is used for plotting the IDF curves. The data is processed using Matlab and GIS software. The IDF curves obtained thus could be widely used for getting a composite idea of what rainfall intensity could be expected for a desired duration and a given frequency of rainfall. IDF'S can also be used for developing hydrographs for getting a rough idea of maximum discharge, which would be further useful in planning urban drainage works and other hydraulic structures such as culverts, spillways, dams e.t.c and thus indirectly by flood forcasting preventing urban flooding, helping in storm water drainage and discarding the chances of waterlogging and various other ill effects of flooding.
KEYWORDS: Gumbels distribution, hydrographs, flood forcasting, TRMM, IDF curves