Resolving orographic rainfall on the Indian west coast
DRS at CSIR-National Institute of Oceanography
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Title |
Resolving orographic rainfall on the Indian west coast
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Creator |
Suprit, K.
Shankar, D. |
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Subject |
hydrological modelling
multivariate interpolation orographic rainfall ridge Sahyadris Western Ghats freshwater discharge Mandovi river salinity Indian Ocean |
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Description |
We discuss a method to obtain the spatial estimates of rainfall on the Indian west coast for calculating the surface water budget. The region includes the basin of the Mandovi River, a typical west-coast river whose catchment area includes the Sahyadris range. The rainfall maps obtained by a multivariate interpolation scheme, with elevation as the third variable, were able to capture the sharp increase in rainfall on the windward slopes and the exponential decay in rainfall on the leeward side. The rainfall maps were used to force a hydrological model and the simulated discharge was within 16% of the observed discharge in 16 of 18 years during 1981–1998; the average error over the 18 years was 8%, which is much less than the estimated error of ~15–20% in the observed discharge. The Mandovi river discharge provided a reliable and independent validation of the accuracy of the rainfall estimate as the river is purely rain-fed. The method provides a better estimate of rainfall in the Mandovi basin, and therefore for the Indian west coast, than existing rainfall datasets. The key result is that treating the windward and leeward sides separately by an a priori, subjective extraction of the ridge line can reduce the underestimation of rainfall that is common in mountainous terrain when the data coverage is sparse.
CSIR, DOD. |
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Date |
2007-08-01T07:10:29Z
2007-08-01T07:10:29Z 2008 |
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Type |
Journal Article
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Identifier |
International Journal of Climatology, vol.28(5); 643-657, DOI: 10.1002/joc.1566
0899-8418 http://drs.nio.org/drs/handle/2264/645 |
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Language |
en
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Rights |
This is a preprint of an article published in [International Journal of Climatology, DOI: 10.1002/joc.1566]”and located at the following Wiley URL: http://www3.interscience.wiley.com/cgi-bin/jhome/4735. Copyright[2007] Royal Meteorological Society |
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Format |
958597 bytes
application/pdf |
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Publisher |
Royal Meteorological Society
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