B4. Sources Database SOURCES.DAT
Other Databases: SOILS.DAT, PROFILS.DAT, PLANTS.DAT
Related Stuff: Additional local databases (.CF file)
Introduction
ENVI-met allows to simulate the release and dispersion of gases and particles. To used this option, you must add Sources to the Area-Input file.
At the moment, all sources in the model must be of the same type, e.g. they all have to be S02 sources. You cannot have for example one SO2 source and a NOx source in the model at the same time.
Due to the significant amount of information needed to place sources in the model, the information about the sources is stored in three different locations:
a) the location of the sources is stored in the Area-Input File
b) the type of source is defined in the [SOURCES]-section of the Configuration File
c) the type and height of the source and the emission rate stored in SOURCES.DAT or the optional local database (this section).
So basically, the concept is the same as for plants and soils: a two-char ID is placed in the in the Area Input file and a number of databases is used to define how this ID behaves. However, the separation between the emission rate and the definition of the type of source is a bit artificial. This might be changed in later versions.
Information stored in SOURCES.DAT and optional local database
The database file contains information about
This is an example for a SOURCES.DAT file:
01: ----- Sources-Database. Type (T) 1,4=point, 2,5=line 3,6=area, E in mg/s (1), mg/s*m (2) or mg/s*m² (3), µg/s (4), µg/s*m (5) or µg/s*m² (6)
02: ID T hh.hh E(00h) E(01h) ... E(23h) Name (40)
03: xx 5 0.30 010.00 010.00 ... 010.00 Test_Pointsource 10m,10mg/s
What do the lines and columns mean?
The first two lines are headers to indicate the position of the different data entries.
The meaning of the columns is:
ID: the two-digit ID which links the sources data to the Area Input file.
ENVI-met uses non-case sensitive IDs, "xx" is the same as "XX"
T: Type of source and information, in which unit the emission data is stored
Possible types are Point source (T=1) in mg/s,
Line Source (2) in mg/(s*m) and
Area Source (3) in mg/(s*m²)
If the emission data is given in µg/.. instead of mg/... use types 4,5 and 6 respectively
hh.hh: Height of source in m. (Will be adjusted to grid mesh by ENVI-met)
E(00h) Emission rate at 00.00,
E(01h) Emission rate at 01.00
... and so on until....
E(23) Emission rate at 23.10 (links to the Emission rate at 00.00 for interpolation)
Name Given name for source (up to 40 chars)
The data for the emission rates is dynamically adjusted during the simulation according to the hour of simulation (linear interpolation).