Does the GPM mission improve the systematic error component in satellite rainfall estimates over TRMM? An evaluation at a pan-India scale
The last couple of decades have seen the outburst of a number of satellite-based precipitation products with Tropical Rainfall Measuring Mission (TRMM) as the most widely used for hydrologic applications. Transition of TRMM into the Global Precipitation Measurement (GPM) promises enhanced spatio-...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2017-12-01
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| Series: | Hydrology and Earth System Sciences |
| Online Access: | https://www.hydrol-earth-syst-sci.net/21/6117/2017/hess-21-6117-2017.pdf |
| Summary: | The last couple of decades have seen the outburst of a number of satellite-based
precipitation products with Tropical Rainfall Measuring Mission (TRMM) as the
most widely used for hydrologic applications. Transition of TRMM into the Global
Precipitation Measurement (GPM) promises enhanced spatio-temporal resolution
along with upgrades to sensors and rainfall estimation techniques. The dependence
of systematic error components in rainfall estimates of the Integrated
Multi-satellitE Retrievals for GPM (IMERG), and their variation with
climatology and topography, was evaluated over 86 basins in India for year
2014 and compared with the corresponding (2014) and retrospective (1998–2013)
TRMM estimates. IMERG outperformed TRMM for all rainfall intensities across a
majority of Indian basins, with significant improvement in low rainfall
estimates showing smaller negative biases in 75 out of 86 basins. Low
rainfall estimates in TRMM showed a systematic dependence on basin
climatology, with significant overprediction in semi-arid basins, which
gradually improved in the higher rainfall basins. Medium and high rainfall
estimates of TRMM exhibited a strong dependence on basin topography, with
declining skill in higher elevation basins. The systematic dependence of error
components on basin climatology and topography was reduced in IMERG,
especially in terms of topography. Rainfall-runoff modeling using the Variable
Infiltration Capacity (VIC) model over two flood-prone basins (Mahanadi and
Wainganga) revealed that improvement in rainfall estimates in IMERG did not
translate into improvement in runoff simulations. More studies are required
over basins in different hydroclimatic zones to evaluate the hydrologic
significance of IMERG. |
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| ISSN: | 1027-5606 1607-7938 |