Abstract
Earth system models (ESMs) are currently the most advanced tools with which to study the interactions among humans, ecosystem productivity, and the climate. The inclusion of storm damage in ESMs has long been hampered by their big-leaf approach, which ignores the canopy structure information that is required for process-based wind-throw modelling. Recently the big-leaf assumptions in the large-scale land surface model ORCHIDEE-CAN were replaced by a three-dimensional description of the canopy structure. This opened the way to the integration of the processes from the small-scale wind damage risk model ForestGALES into ORCHIDEE-CAN. The integration of ForestGALES into ORCHIDEE-CAN required, however, developing numerically efficient solutions to deal with (1) landscape heterogeneity, i.e. account for newly established forest edges for the parameterization of gusts; (2) downscaling spatially and temporally aggregated wind fields to obtain more realistic wind speeds that would represents gusts; and (3) downscaling storm damage within the 2500ĝ€-km2 pixels of ORCHIDEE-CAN. This new version of ORCHIDEE-CAN was parameterized over Sweden. Subsequently, the performance of the model was tested against data for historical storms in southern Sweden between 1951 and 2010 and south-western France in 2009. In years without big storms, here defined as a storm damaging less than 15ĝ€- × ĝ€-106ĝ€-m3 of wood in Sweden, the model error is 1.62ĝ€- × ĝ€-106ĝ€-m3, which is about 100ĝ€-% of the observed damage. For years with big storms, such as Gudrun in 2005, the model error increased to 5.05ĝ€- × ĝ€-106ĝ€-m3, which is between 10 and 50ĝ€-% of the observed damage. When the same model parameters were used over France, the model reproduced a decrease in leaf area index and an increase in albedo, in accordance with SPOT-VGT and MODIS records following the passing of Cyclone Klaus in 2009. The current version of ORCHIDEE-CAN (revision 4262) is therefore expected to have the capability to capture the dynamics of forest structure due to storm disturbance on both regional and global scales, although the empirical parameters calculating gustiness from the gridded wind fields and storm damage from critical wind speeds may benefit from regional fitting.
Original language | English |
---|---|
Pages (from-to) | 771-791 |
Number of pages | 21 |
Journal | Geoscientific Model Development |
Volume | 11 |
Issue number | 2 |
DOIs | |
Publication status | Published - 2 Mar 2018 |
Funding
Acknowledgements. This work was funded through a bilateral agreement between the Swedish Research Council (VR) and the French Alternative Energies and Atomic Energy Commission (LSCE-IPSL, CEA, CNRS, and UVSQ). Part of the computational resources was provided by the Research Center for Environmental Changes (RCEC) at Academia Sinica (RCEC, AS) and the National Central University (NCU) in Taiwan. Yi-Ying Chen received funding through the Ministry of Science and Technology, R.O.C. (MOST 106-2111-M-001-001-MY3). Sebastiaan Luyssaert was funded in part through an Amsterdam Academic Alliance fellowship. We thank the two anonymous reviewers and the editor, Hisashi Sato, for their very helpful observations and suggestions.
Funders | Funder number |
---|---|
LSCE-IPSL | |
Ministry of Science and Technology | |
Natural Environment Research Council | NE/I022183/1 |
Vetenskapsrådet | |
Ministry of Science and Technology, Taiwan | 106-2111-M-001-001-MY3 |
Centre National de la Recherche Scientifique | |
National Central University | |
Commissariat à l'Énergie Atomique et aux Énergies Alternatives |