Converting climate change gridded daily rainfall to station daily rainfall—a case study at zengwen reservoir
Journal
Water (Switzerland)
Journal Volume
13
Journal Issue
11
Date Issued
2021
Author(s)
Abstract
With improvements in data quality and technology, the statistical downscaling data of General Circulation Models (GCMs) for climate change impact assessment have been refined from monthly data to daily data, which has greatly promoted the data application level. However, there are differences between GCM downscaling daily data and rainfall station data. If GCM data are directly used for hydrology and water resources assessment, the differences in total amount and rainfall intensity will be revealed and may affect the estimates of the total amount of water resources and water supply capacity. This research proposes a two-stage bias correction method for GCM data and establishes a mechanism for converting grid data to station data. Five GCMs were selected from 33 GCMs, which were ranked by rainfall simulation performance from a baseline period in Taiwan. The watershed of the Zengwen Reservoir in southern Taiwan was selected as the study area for comparison of the three different bias correction methods. The results reveal that the method with the wet-day threshold optimized by objective function with observation rainfall wet days had the best result. Error was greatly reduced in the hydrology model simulation with two-stage bias correction. The results show that the two-stage bias correction method proposed in this study can be used as an advanced method of data pre-processing in climate change impact assessment, which could improve the quality and broaden the extent of GCM daily data. Additionally, GCM ranking can be used by researchers in climate change assessment to understand the suitability of each GCM in Taiwan. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
Subjects
GCMs ranking; General circulation model; Probability of precipitation; Statistical downscaling daily data; Two-stage bias correction method
Other Subjects
Climate models; Data handling; Electromagnetic wave attenuation; Hydrology; Rain; Reservoirs (water); Water resources; Water supply; Bias-correction methods; Climate change assessment; Climate change impact assessments; General circulation model; Hydrology and water resource; Objective functions; Rainfall simulations; Statistical downscaling; Climate change; climate change; data quality; detection method; general circulation model; observational method; precipitation intensity; rainfall; reservoir; simulation; watershed; Taiwan
Type
journal article