Output Files: Atmosphere data (_AT_)

Dimension Nr Variables Format
3D 43 (with Water Spray) Binary (EDX/EDT)

Atmosphere Data

Contains the general model state of the 3D atmospheric ENVI-met model from the first level above ground to the top of the 3D model.

The Atmosphere data files are produced each main output interval (default: 60 min) and represent the general state of the atmosphere at the given model time. These files contain a broad selection of different items from simple meteorological data such as wind speed and air temperature up to detailed information such as plant CO2 fluxes. Using the _AT_ files, most of the processes in the atmosphere can be analysed. However, there are further files concerning the atmosphere dealing with more specific topics such as radiation or pollutant dispersions.

Note, that the surface data are not part of the atmosphere data, but of the Surface/ Flux (_FX_) files.

If you use Water Spray in your simulation, the data on the spray distribution and cooling effect are also stored in this file.

Variable list

Variable Unit Description
Objects - Single object IDs to visualize the model domain: 1: Building, 2: Terrain, 4: Containes Source, 11 -15: Vegetation with increasing LAD. These definitions are also stored in the default LEONARDO Special Layer Definition File
Flow u m/s Wind speed. Vector component along the West-East axis (+: East, -: West)
Flow v m/s Wind speed. Vector component along the North-South axis (+: South, -: North)
Flow w m/s Wind speed. Vector component along the vertical axis (+: up, -: down)
Wind Speed m/s Wind speed. Vector sum over all 3 axis
Wind Speed Change % Wind speed change in percent referring to the undisturbed inflow profile at the same height level.
Wind Direction deg Wind direction of horizontal component in geographic reference (0: N..90:E..180:S etc)
Pressure Perturbation Pa Dynamic pressure as a result of the wind field calculation. Pressure values will add up over time, use spatial difference values only if required
Potential Air Temperature °C Potential air temperature at reference (and model default) pressure. For the 3D model, it can be treated like the absolute air temperature
Air Temperature Delta K Difference between the local air temperature and the reference air temperature at inflow at the same height level
Air Temperature Change K/h Changes of air temperature compared to the last _AT_ output file
Specific Humidity g/kg Specific air humidity
Relative Humidity % Relative air humidity (Caution: Depends both on Specific air humidity and air temperature)
TKE m²/m³ Local Turbulent Kinetic Energy
Dissipation m³/m³ Local dissipation rate of Turbulent Kinetic Energy
Mean Radiant Temperature °C The composed radiative fluxes and air temperature for a standing person
Vertical Exchange Coefficient Impulse m²/s Calculated vertical exchange coefficient for impulse
Horizontal Exchange Coefficient Impulse m²/s Calculated horizontal exchange coefficient for impulse (At the moment for microscale assumed to be equal to the vertical exchange coefficient)
Direct Shortwave Radiation W/m² Available direct solar radiation referring to a reference surface perpendicular to the incoming sun rays (maximum value before applying Lamberts' law)
Diffuse Shortwave Radiation W/m² Available diffuse solar radiation referring to a horizontal reference surface
Reflected Shortwave Radiation W/m² Availablereflected solar radiation from the environment referring to a horizontal reference surface
Air Temperature Change through LW Cooling K/h Effect of longwave radiation divergence on air temperature per time

Vegetation Data

Vegetation LAD m²/m³ One-sided Leaf Area Density (Surface of leaf area per m³ air)
Leaf Temperature °C Temperature of the leaf
Temperature Flux at Leaf K*m/s Temperature Flux in K from leaf to atmosphere
Stomata Resistance s/m Actual resistance of stomata to vapour transfer
Vapour Flux at Leaf g/kg*m/s Evaportation and transpiration flux on leaf per leaf area unit
Water on Leafes g/ m² Liquid water on leaf per leaf area


CO2 mg/m³ Atmospheric CO2
CO2 ppm Atmospheric CO2
CO2 Flux at Leaf mg/kg*m/s CO2 Flux at leaf per leaf area unit

Water Spray (only if active)

Spray source g/s Actual emission rate of water spray at source
Spray concentration g/m³ Mass of water spray in the air
Spray evaporation g/(m³s) Local evaporation rate of water spray
Spray Cooling K/s Local cooling rate of air due to water spray evaporation

Other Data

Local Mixing Length m Local mixing length calculated from TKE model
TKE normalised with 1D model - Local TKE normlized to 1 with 1D reference model
Dissipation normalised with 1D model - Local TKE dissiplation normlized to 1 with 1D reference model
Km normalised with 1D model - Local Km normlized to 1 with 1D reference model
TKE Mechanical Turbulence Production ( ) Local TKE mechnical production normlized to 1 with 1D reference model
Div Rlw Temp change K/h Radiative cooling/heating rate of air due to longwave radiation divergence
Building Number - Internal Building Number
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