Impact of correcting sub-daily climate model biases for hydrological studies
<p>The study of climate change impact on water resources has accelerated worldwide over the past 2 decades. An important component of such studies is the bias-correction step, which accounts for spatiotemporal biases present in climate model outputs over a reference period, and which allows fo...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2022-03-01
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| Series: | Hydrology and Earth System Sciences |
| Online Access: | https://hess.copernicus.org/articles/26/1545/2022/hess-26-1545-2022.pdf |
| Summary: | <p>The study of climate change impact on water resources has accelerated worldwide over the past 2 decades. An important component of such studies is the bias-correction step, which accounts for spatiotemporal biases present in climate model outputs over a reference period, and which allows for realistic streamflow simulations using future climate scenarios. Most of the literature on bias correction focuses on daily scale climate model
temporal resolution. However, a large amount of regional and global climate simulations are becoming increasingly available at the sub-daily time
step, and even extend to the hourly scale, with convection-permitting models exploring sub-hourly time resolution. Recent studies have shown that
the diurnal cycle of variables simulated by climate models is also biased, which raises issues respecting the necessity (or not) of correcting such
biases prior to generating streamflows at the sub-daily timescale. This paper investigates the impact of bias-correcting the diurnal cycle of
climate model outputs on the computation of streamflow over 133 small to large North American catchments. A standard hydrological modeling chain was
set up using the temperature and precipitation outputs from a high spatial (0.11<span class="inline-formula"><sup>∘</sup></span>) and temporal (1 <span class="inline-formula">h</span>) regional climate model large
ensemble (ClimEx-LE). Two bias-corrected time series were generated using a multivariate quantile mapping method, with and without correction of the
diurnal cycles of temperature and precipitation. The impact of this correction was evaluated on three small (<span class="inline-formula"><</span> 500 <span class="inline-formula">km<sup>2</sup></span>), medium (between 500 and 1000 <span class="inline-formula">km<sup>2</sup></span>), and large (<span class="inline-formula">></span> 1000 <span class="inline-formula">km<sup>2</sup></span>) surface area catchment size classes. Results show relatively small (3 % to 5 %) but systematic decreases in the relative error of most simulated flow quantiles when bias-correcting the diurnal cycle of precipitation and temperature. There was a clear relationship with catchment size, with improvements being most noticeable for the small catchments. The diurnal cycle correction allowed for hydrological simulations to accurately represent the diurnal cycle of summer streamflow in small catchments. Bias-correcting the diurnal cycle of precipitation and temperature is therefore recommended when conducting impact studies at the sub-daily timescale on small catchments.</p> |
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| ISSN: | 1027-5606 1607-7938 |