Bias correction of dynamically downscaled precipitation to compute soil water deficit for explaining year-to-year variation of tree growth over northeastern France

Authors
Boulard, Damien; Castel, Thierry; Camberlin, Pierre; Sergent, Anne Sophie; Asse, Daphné; Bréda, Nathalie; Badeau, Vincent; Rossi, Aurélien; Pohl, Benjamin
Publication Year
2017
Language
English
Format
article
Status
Published version
Description
This paper documents the accuracy of a post-correction method applied to precipitation regionalized by the Weather Research and Forecasting (WRF) Regional Climate Model (RCM) for improving simulated rainfall and feeding impact studies. The WRF simulation covers Burgundy (northeastern France) at a 8-km resolution and over a 20-year long period (1989–2008). Previous results show a strong deficiency of the WRF model for simulating precipitation, especially when convective processes are involved. In order to reduce such biases, a Quantile Mapping (QM) method is applied to WRF-simulated precipitation using the mesoscale atmospheric analyses system SAFRAN («Système d'Analyse Fournissant des Renseignements Adaptés à la Nivologie») that provides precipitation data at an 8 km resolution. Raw and post-corrected model outputs are next used to compute the soil water balance of 30 Douglas-fir and 57 common Beech stands across Burgundy, for which radial growth data are available. Results show that the QM method succeeds at reducing the model's wet biases in spring and summer. Significant improvements are also noted for rainfall seasonality and interannual variability, as well as its spatial distribution. Based on both raw and post-corrected rainfall time series, a Soil Water Deficit Index (SWDI) is next computed as the sum of the daily deviations between the relative extractible water and a critical value of 40% below which the low soil water content induce stomatal regulation. Post-correcting WRF precipitation does not significantly improve the simulation of the SWDI upon the raw (uncorrected) model outputs. Two characteristic years were diagnosed to explain this unexpected lack of improvement. Although the QM method allows producing realistic precipitation amounts, it does not correct the timing errors produced by the climate model, which is yet a major issue to obtain reliable estimators of local-scale bioclimatic conditions for impact studies. A realistic temporality of simulated precipitation is thus required before using any systematic post-correction method for appropriate climate impact assessment over temperate forests.
Fil: Boulard, Damien. Universite de Bourgogne; Francia
Fil: Castel, Thierry. Universite de Bourgogne; Francia
Fil: Camberlin, Pierre. Universite de Bourgogne; Francia
Fil: Sergent, Anne Sophie. Institut National de la Recherche Agronomique; Francia. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Patagonia Norte. Estación Experimental Agropecuaria San Carlos de Bariloche; Argentina
Fil: Asse, Daphné. Crea Centre de Recherches Sur Les Ecosystèmes Daltitud; Francia
Fil: Bréda, Nathalie. Institut National de la Recherche Agronomique; Francia
Fil: Badeau, Vincent. Institut National de la Recherche Agronomique; Francia
Fil: Rossi, Aurélien. Universite de Bourgogne; Francia
Fil: Pohl, Benjamin. Universite de Bourgogne; Francia
Subject
COMMON BEECH
DOUGLAS-FIR
QUANTILE MAPPING
REGIONAL CLIMATE MODELLING
SOIL WATER DEFICIT
WATER BALANCE
WRF
Meteorología y Ciencias Atmosféricas
Ciencias de la Tierra y relacionadas con el Medio Ambiente
CIENCIAS NATURALES Y EXACTAS
Access level
Restricted access
License
https://creativecommons.org/licenses/by-nc-nd/2.5/ar/
Repository
CONICET Digital (CONICET)
Institution
Consejo Nacional de Investigaciones Científicas y Técnicas
OAI Identifier
oai:ri.conicet.gov.ar:11336/65536