A holistic microclimate model

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remark_1_flux [2012/07/07 00:58] – 134.93.180.188remark_1_flux [2012/07/07 01:02] – 134.93.180.188
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-So, we get for the longwave radiation from the **free sky (LW_free)**:+So, we get for the longwave radiation from the **free sky (''LW_free'')**: 
 +  LW_free= trans_plant*LW_sky+ (1-trans_plant)*LW_plant\\ 
 +where ''LW_sky'' is the atmospheric counter radiation and ''LW_plant'' is the radiation of the leafs (averaged over a vertical column)
  
- +For the **obstructed sky ''(LW_obst)''**, the rule is: 
 +  //LW_obst= max(q_lw_envi,q_lwsurf)//
  
-LW_free= trans_plant*LW_sky+ (1-trans_plant)*LW_plant+where ''q_LW_envi'' is an averaged value over all facade temperatures in the model  and ''q_lwsurf'' is the longwave radiation of the surface concerned itself. The "max" function ensures that the highest of the values is used (see above)
  
-  +Finally, the total incoming longwave radiation is weighted between ''LW_free'' and ''LW_obst'' using the ''SVF'': 
- +  //LW_total= SVF*LW_free+(1-SVF)*LW_obst//
-where LW_sky is the atmospheric counter radiation and LW_plant is the radiation of the leafs (averaged over a vertical column) +
- +
-  +
- +
-For the **obstructed sky (LW_obst)**, the rule is: +
- +
-  +
- +
-LW_obst= max(q_lw_envi,q_lwsurf) +
- +
-  +
- +
-where q_LW_envi is an averaged value over all facade temperatures in the model  and q_lwsurf is the longwave radiation of the surface concerned itself. The "max" function ensures that the highest of the values is used (see above) +
- +
-  +
- +
-Finally, the total incoming longwave radiation is weighted between LW_free and LW_obst using the SVF: +
- +
-  +
- +
-LW_total= SVF*LW_free+(1-SVF)*LW_obst +
- +
- +
  
 The values found in the receptor files for radiation coming from the vegetation, the sky and from the environment are based on this calculation for the selected surface: The values found in the receptor files for radiation coming from the vegetation, the sky and from the environment are based on this calculation for the selected surface:
- +  //from vegetation = SVF*(1-trans_plant)*LW_plant
-  +
- +
-from vegetation = SVF*(1-trans_plant)*LW_plant+
 from sky=SVF*trans_plant*LW_sky  from sky=SVF*trans_plant*LW_sky 
-from environment= (1-SVF)*max(q_lw_envi,q_lwsurf)+from environment= (1-SVF)*max(q_lw_envi,q_lwsurf)//
  
    
 They are **NOT** the total amount of longwave radiation **emitted** (e.g. from the plants) but the amount of radiation **reaching** the surface of interest!  They are **NOT** the total amount of longwave radiation **emitted** (e.g. from the plants) but the amount of radiation **reaching** the surface of interest!