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rodos:alsmc_prognosis_adm_atprogn.f_2008.05 [2008/07/10 09:14]
ju created
rodos:alsmc_prognosis_adm_atprogn.f_2008.05 [2015/03/24 15:32] (current)
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 === 1) Determination of effective local roughness length z0 from Rogis land-use data(similar to Atdiagn.f): === === 1) Determination of effective local roughness length z0 from Rogis land-use data(similar to Atdiagn.f): ===
 === Before Patch 2008.05: === === Before Patch 2008.05: ===
-Effective local roughness length was determined from averaging the land-use-grid ​+Effective local roughness length was determined from averaging the land-use-grid
 related roughness length over a square area of 4000 x 4000 m2. related roughness length over a square area of 4000 x 4000 m2.
 === Now: === === Now: ===
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 === 2) Change of sigma parameters of a puff during change from time step M to M+1. === === 2) Change of sigma parameters of a puff during change from time step M to M+1. ===
 === Before Patch 2008.05: === === Before Patch 2008.05: ===
-Due to change of turbulence from step M to M+1 (either by change of stability class  +Due to change of turbulence from step M to M+1 (either by change of stability class or by change of roughness length) the sigma parameters of a puff can only increase, never decrease. This increase was applied both to the sigma parameters at puff head and puff end.
-or by change of roughness length) the sigma parameters of a puff can only increase, ​ +
-never decrease. This increase was applied both to the sigma parameters at puff head  +
-and puff end.+
 === Now: === === Now: ===
-  *This increase is applied to the sigma at puff head only, the sigma parameters at  +  *This increase is applied to the sigma at puff head only, the sigma parameters at puff end stay the same as the sigma parameters at the head of the puff at the time step before. This makes a more realistic smooth transition of the puff size.
-puff end stay the same as the sigma parameters at the head of the puff at the time  +
-step before. This makes a more realistic smooth transition of the puff size.+
 ===  === ===  ===
 === 3) Effective transport velocity of a long puff (time step 1800s or 3600s) during release. === === 3) Effective transport velocity of a long puff (time step 1800s or 3600s) during release. ===
 === Before Patch 2008.05: === === Before Patch 2008.05: ===
-The effective transport velocity of a puff during release from the source was the  +The effective transport velocity of a puff during release from the source was the wind velocity at source height. Especially at low release heights this could cause a too short initial puff length because the increase of the vertical size of the puff was neglected. During the following time step the end of this puff again was transported with that speed, but the head was transported with a vertical mass profile weighted enhanced speed.
-wind velocity at source height. Especially at low release heights this could cause  +
-a too short initial puff length because the increase of the vertical size of the  +
-puff was neglected. During the following time step the end of this puff again was  +
-transported with that speed, but the head was transported with a vertical mass  +
-profile weighted enhanced speed.+
 === Now: === === Now: ===
-  *The effective transport velocity of a puff during release from the source is  +  *The effective transport velocity of a puff during release from the source is modified: it is 50% urel plus 50% u100 for stability A to E, and 70% urel plus 30% u100 for stability F. (urel is wind speed at release height).
-modified: it is 50% urel plus 50% u100 for stability A to E, and 70% urel plus 30%  +
-u100 for stability F. (urel is wind speed at release height).+
 ===  === ===  ===
 === 4) Averaged sideward transport of a long puff if wind speeds at head and end of puff differ very much. === === 4) Averaged sideward transport of a long puff if wind speeds at head and end of puff differ very much. ===
 === Before Patch 2008.05: === === Before Patch 2008.05: ===
-In cases of sideward transport of a long puff with strong difference of  +In cases of sideward transport of a long puff with strong difference of displacements at puff head and puff end it could happen that the geometry of the parallelogram needed for calculation of time-integrated concentrations failed.
-displacements at puff head and puff end it could happen that the geometry of the  +
-parallelogram needed for calculation of time-integrated concentrations failed.+
 === Now: === === Now: ===
-  *If there is transport of the long puff to sideward, and if the relative ​ +  *If there is transport of the long puff to sideward, and if the relative difference of displacements of puff head and puff end would exceed 20 %, then transport of the puff is calculated with the average of wind vectors at puff head and puff end.
-difference of displacements of puff head and puff end would exceed 20 %, then  +
-transport of the puff is calculated with the average of wind vectors at puff head  +
-and puff end.+
  
rodos/alsmc_prognosis_adm_atprogn.f_2008.05.1215674079.txt.gz · Last modified: 2015/03/24 15:32 (external edit)