Gauge-Based Adjustment of Historical Multi-Sensor Quantitative Precipitation Fields and Resulting Effects on Hydrologic Simulations

This study presents two rain gauge-based re-adjustment schemes aimed at mitigating the biases in archival Multisensor Quantitative Precipitation Estimates (MQPEs) produced by the National Weather Service (NWS). The first and the second schemes re-adjust the MQPEs on monthly and daily scales to match two gridded gauge-only analyses at the respective time scale. These schemes were applied to archival MQPEs from the Mid-Atlantic River Forecasting Center (MARFC) for 1997–2006 and their effects were examined through streamflow simulations for twelve catchments in the state of Maryland. The results were compared with observed streamflow for two periods divided along November 2003, when a software error that contributed to earlier low bias was corrected. The results indicate that either scheme improved the temporal consistency of MQPE bias, though the monthly scheme was slightly more effective. Between the two periods, the adjustment schemes were generally more effective in the earlier one than the latter one.