Abstract
The rapid development of Satellite Precipitation Products (SPPs) has heightened the need for a hydro-meteorological assessment of the Integrated Multi-satellite Retrievals for Global Precipitation Measurement (IMERG) products in different climate and geographical regions. Reliability of the IMERG early (IMERG_E), late (IMERG_L) and final (IMERG_F) run products in precipitation estimations was evaluated over the Kelantan River Basin, Malaysia from 12 March 2014 to 31 December 2016. The three IMERG products were then incorporated into a calibrated Soil and Water Assessment Tool (SWAT) model to assess their reliability in streamflow simulations. Overall, monthly precipitation variability is well captured by the three SPPs. The IMERG_F exhibited a smaller systematic bias (RB = 7.14%) compared to the IMERG_E (RB = −10.42%) and IMERG_L (RB = −17.92%) in daily precipitation measurement. All the three SPPs (NSE = 0.66~0.71 and R2 = 0.73~0.75) performed comparably well as precipitation gauges (NSE = 0.74 and R2 = 0.79) in the daily streamflow simulation. However, the IMERG_E and IMERG_L showed a significant underestimation of daily streamflow by 27.6% and 36.3%, respectively. The IMERG_E and IMERG_F performed satisfactory in streamflow simulation during the 2014–2015 flood period, with NSE and R2 values of 0.5~0.51 and 0.62~0.65, respectively. With a better peak flow capture ability, the IMERG_F outperformed the near real-time products in cumulative streamflow measurement. The study has also shown that the point-to-pixel or pixel-to-pixel comparison schemes gave comparable conclusions. Future work should focus on the development of a standardized GPM hydro-meteorological assessment framework, so that a fair comparison among IMERG validation studies can be conducted.
Highlights
For the Integrated Multi-satellite Retrievals for Global Precipitation Measurement (IMERG) products, we only considered the pixels over precipitation gauges (Figure 1) to reduce the uncertainty in this assessment
The peak flow simulated by the IMERG_L was found a day earlier. These findings indicate that the IMERG early (IMERG_E) and IMERG final run (IMERG_F) can be alternative precipitation sources to monitor the flood event of the basin
The purpose of the current study was to assess the reliability of the IMERG products (IMERG_E, IMERG_L and IMERG_F) in hydro-meteorological applications in the Kelantan River Basin (KRB), Malaysia
Summary
Precipitation replenishes the water resources on Earth via the hydrological cycle, which are essential for agricultural, industrial, domestic, and drinking purposes. An understanding of precipitation patterns is obviously important in water resources management. Apart from this, reliable precipitation information is vital in monitoring and forecasting water-related hazards such as flood and drought. Sustainable development of the economic, agricultural, ecological, and social fields requires accurate precipitation data. A precipitation gauge is regarded as one of the most reliable approaches of collecting precipitation information, but it is in point form. Various interpolation techniques such as Kringing, Inverse Distance
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