| 5 | | For each ORCHIDEE-dev meeting a main organizer is decided during a weekly meeting as well as the main theme of the meeting. The main organizer will then organize the meeting as much as possible outside the weekly meetings. |
| | 5 | |
| | 6 | ORCHIDEE DEV meetings are scheduled every 2 months or so by the ORCHIDEE projet group. If you want to present your work on this occasion or if you have any suggestion of topic to be discussed, do not hesitate to get in touch with us to organize it ! |
| | 7 | |
| | 8 | Contact : Juliette Lathière (LSCE) juliette.lathiere@lsce.ipsl.fr |
| | 9 | |
| | 10 | = ORCHIDEE DEV meetings agenda = |
| | 11 | |
| | 12 | |
| | 13 | == 12/07/2022 High resolution (visioconference) == |
| | 14 | |
| | 15 | With presentations by: |
| | 16 | |
| | 17 | - '''Jan Polcher''' : The WCRP and GEWEX strategies around km-scale Earth system modelling ; |
| | 18 | - '''Frédérique Cheruy''' : De la très haute résolution au modèle global de climat: L'expérience LMDZ ; |
| | 19 | - '''Philippe Peylin''' : A flexible multi energy/water budget to account for surface heterogeneity ; |
| | 20 | - '''Sebastiaan Luyssaert''' : Digital twins and high resolution models . |
| | 21 | |
| | 22 | == 21/06/2022 Atmospheric dryness and photosynthesis (visioconference) == |
| | 23 | |
| | 24 | '''Zheng Fu''' (post-doctorate researcher at LSCE) presented his work regarding "Atmospheric dryness reduces photosynthesis along a large range of soil water deficits": |
| | 25 | |
| | 26 | Abstract: Both low soil water content (SWC) and high atmospheric dryness (vapor pressure deficit, VPD) can negatively affect terrestrial gross primary production (GPP). The sensitivity of GPP to soil versus atmospheric dryness is difficult to disentangle, however, because of their covariation. Using global eddy-covariance observations, here we show that a decrease in SWC is not universally associated with GPP reduction. GPP increases in response to decreasing SWC when SWC is high and decreases only when SWC is below a threshold. By contrast, the sensitivity of GPP to an increase of VPD is always negative across the full SWC range. We further find canopy conductance decreases with increasing VPD (irrespective of SWC), and with decreasing SWC on drier soils. Maximum photosynthetic assimilation rate has negative sensitivity to VPD, and a positive sensitivity to decreasing SWC when SWC is high. Earth System Models underestimate the negative effect of VPD and the positive effect of SWC on GPP such that they should underestimate the GPP reduction due to increasing VPD in future climates. |
| | 27 | |
| | 28 | = Reports from earlier ORCHIDEE developpers meetings = |
