Home > User’s guide > 3. Off-line Guide > 3.3. One example of off-line surfex application > 3.3.2. ascii format files > 3.3.2.1. PGD.txt

3.3.2.1. PGD.txt

This file contains the information related to physiography and orography essentially. The file is splitted into several parts. The first one corresponds to the gridbox as seen as a single pixel where quantities are aggregated. The corresponding field names are prefixed with FULL. This gridbox may be separated into four tiles respectively associated to nature, town, sea/ocean and lake). The corresponding field names are respectively prefixed with NATURE, TOWN, SEA and WATER.
The physiographic parameters written out into PGD.txt file are mainly the fraction of land covers contained in each gridbox. These fractions are computed from ECOCLIMAP database.

 &FULL   DIM_FULL        
(-)                                               
 1280
 &FULL   DIM_SEA         
(-)                                               
 0
 &FULL   DIM_NATURE      
(-)                                               
 1279
 &FULL   DIM_WATER       
(-)                                               
 1
 &FULL   DIM_TOWN        
(-)                                               
 240
 &FULL   ECOCLIMAP       
(-)                                               
 T
 &NATURE ISBA            
ISBA                                              
3-L                                     
 &NATURE PHOTO           
PHOTO                                             
NON                                     
 &NATURE GROUND_LAYER    
GROUND_LAYER                                      
 3
 &NATURE PATCH_NUMBER    
PATCH_NUMBER                                      
 1

Value of DIM_FULL indicates that this is a 2D exercise, and the gridbox contains a non-zero fraction of nature, of water (lake) and of town, but there's no fraction of sea because the number of points with a non-zero fraction of sea DIM_SEA is zero. 1279 gridboxes contain vegetation and 240 gridboxes contain a fraction of town, onmly one gridbow contains a fraction ok inland water(lake). Surface scheme to treat vegetation is Isba 3-L which means that soil is represented with 3 layers. The number of patches is 1, it indicates that the vegetation is not splitted into patches like it could (this should be the case for the A-gs option of Isba that treats explicitly photosynthesis).

Figure 3.5: Orography field taken from PGD.txt file

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