start:hype_model_description:processes_above_ground
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start:hype_model_description:processes_above_ground [2018/08/10 15:40] cpers [Temperature adjustments] |
start:hype_model_description:processes_above_ground [2018/08/10 15:43] cpers [Evaporation] |
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| Subbasin precipitation (//precgc//) is for subbasin average elevation (//basinelev//), but can be adjusted for elevation variations within the subbasin. The precipitation of a class (//prec//) is adjusted for classes where the class average elevation is greater than a threshold (general model parameter //pcelevth//). The adjustment is determined by a general parameter (//pcelevadd//) that is the correction per 100m. The class elevation adjustment can alternatively be determined from the basin standard deviation of elevation (//stdbasinelev//) and a parameter //pcelevstd//. The class height adjustment is limited by a general parameter //pcelevmax//. The precipitation of a class can additionally be adjusted with land-use dependent parameter //pcluse//, e.g. for interception evaporation. | Subbasin precipitation (//precgc//) is for subbasin average elevation (//basinelev//), but can be adjusted for elevation variations within the subbasin. The precipitation of a class (//prec//) is adjusted for classes where the class average elevation is greater than a threshold (general model parameter //pcelevth//). The adjustment is determined by a general parameter (//pcelevadd//) that is the correction per 100m. The class elevation adjustment can alternatively be determined from the basin standard deviation of elevation (//stdbasinelev//) and a parameter //pcelevstd//. The class height adjustment is limited by a general parameter //pcelevmax//. The precipitation of a class can additionally be adjusted with land-use dependent parameter //pcluse//, e.g. for interception evaporation. | ||
| - | <m> precgc=preci×(1+pcaddg)×(1+preccorr)×(1+(pcurain×(1-snowfraction)+pcusnow×snowfraction)) </m> | + | <m> precgc=preci*(1+pcaddg)*(1+preccorr)*(1+(pcurain*(1-snowfraction)+pcusnow*snowfraction)) </m> |
| <m> pcorr_{height}=delim{lbrace}{ | <m> pcorr_{height}=delim{lbrace}{ | ||
| matrix{2}{2}{ | matrix{2}{2}{ | ||
| 0 {basinelev+deltah<pcelevth} | 0 {basinelev+deltah<pcelevth} | ||
| - | {MIN({basinelev+deltah-pcelevth}/{100}×pcelevadd+{stdbasinelev}/{100}×pcelevstd,pcevelmax)} else | + | {MIN({basinelev+deltah-pcelevth}/{100}*pcelevadd+{stdbasinelev}/{100}*pcelevstd,pcevelmax)} else |
| }}{} </m> | }}{} </m> | ||
| - | <m> prec=precgc×(1+pcorr_{height} )×(1-pcluse) </m> | + | <m> prec=precgc*(1+pcorr_{height} )*(1-pcluse) </m> |
| Where //deltah// is a class's elevation deviation from the subbasin average elevation and //snowfraction// is the average fraction of precipitation that falls as snow calculated from subbasin temperature (tempgc) and class-dependent temperature threshold or from input. | Where //deltah// is a class's elevation deviation from the subbasin average elevation and //snowfraction// is the average fraction of precipitation that falls as snow calculated from subbasin temperature (tempgc) and class-dependent temperature threshold or from input. | ||
| Line 90: | Line 90: | ||
| Evaporation from soil is assumed to occur from the two upper layers. The potential evaporation is assumed to decrease exponentially with depth (depending on the parameter //epotdist//). The potential evaporation is divided between the two layers (//epotfrac//) with the distribution depending on the potential evaporation in the midpoint of each soil layer (figure 1). This is then used by approximating to a rectangle. Since soil layers differ between classes, the evaporation distribution do to. | Evaporation from soil is assumed to occur from the two upper layers. The potential evaporation is assumed to decrease exponentially with depth (depending on the parameter //epotdist//). The potential evaporation is divided between the two layers (//epotfrac//) with the distribution depending on the potential evaporation in the midpoint of each soil layer (figure 1). This is then used by approximating to a rectangle. Since soil layers differ between classes, the evaporation distribution do to. | ||
| - | <m> epot1 = EXP(-epotdist*soillayerdepth(1){/}2) </m> | + | <m> epot1 = EXP(- epotdist*soillayerdepth(1){/}2) </m> |
| - | <m> epot2 = EXP(-epotdist*(soillayerdepth(1)+{soillayerdepth(2)- | + | <m> epot2 = EXP(- epotdist*(soillayerdepth(1)+{soillayerdepth(2)- |
| soillayerdepth(1)}/2)) </m> | soillayerdepth(1)}/2)) </m> | ||
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| Line 130: | Line 130: | ||
| The actual evaporation is set to zero for temperatures below the threshold temperature and for negative potential evaporation estimates (condensation). The soil evapotranspiration reduction is calculated as: | The actual evaporation is set to zero for temperatures below the threshold temperature and for negative potential evaporation estimates (condensation). The soil evapotranspiration reduction is calculated as: | ||
| - | <m> factor = 1-e^(-tredA*(soiltemp-ttrig)^tredB) </m> | + | <m> factor = 1-e^( - tredA*(soiltemp-ttrig)^tredB) </m> |
| <m> evapp = evapp*factor </m> | <m> evapp = evapp*factor </m> | ||
start/hype_model_description/processes_above_ground.txt · Last modified: 2024/02/21 08:54 by cpers
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