| 1 | = Soil hydrology = |
| 2 | The default configuration leads to severe water stress of vegetation in particular on clay soils. |
| 3 | All the following has to be added to the PARAM/run.def |
| 4 | |
| 5 | === soil depth === |
| 6 | The default depth of soils in ORCHIDEE is 2m. |
| 7 | You should increase the soil depth to more than 2m in case the actual soils are deeper. |
| 8 | I suggest to use maximum 4m depth, as deeper soil can make problem while are unlikely to improve further the simulated GPP and heat fluxes. |
| 9 | PARAM/run.def: |
| 10 | {{{ |
| 11 | # increase soil depth to 4m: |
| 12 | DEPTH_MAX_H=4.0 |
| 13 | }}} |
| 14 | |
| 15 | === soil resistance to evaporation === |
| 16 | I strongly advise to activate the soil resistance to evaporation when the upper layers dry out. |
| 17 | Without this resistance vegetation on clay soils experience severe water stress during the dry season. |
| 18 | The effect of soil resistance on sandy soils is rather small. |
| 19 | PARAM/run.def: |
| 20 | {{{ |
| 21 | DO_RSOIL=y |
| 22 | }}} |
| 23 | |
| 24 | === re-infiltration of runoff === |
| 25 | I suggest to keep the default value. However, if you are not happy with the evaporation to precipitation ratio (Budyko ratio) you can tune it by increasing or decreasing the re-infiltration of runoff. |
| 26 | The higher the re-infiltration ratio is the higher the Budyko ratio gets. |
| 27 | {{{ |
| 28 | # Increase slope if you want a higher E/P ratio; decrease it if you want a lower E/P ratio; default=0.5 |
| 29 | SLOPE=0.5 |
| 30 | }}} |
| 31 | |