# Main File Surface/Flux (_FLX_)

This section describes the different data field stored in the main file for the surface and fluxes at the surface (…_FLX_…).
This file is only two-dimensional with a constant z=0.

The data stored in the .EDT files are in binary format and can be extracted using LEONARDO or XTract.

FIELD UNIT MEANING
z_topo m Absolute Height of Model Ground Surface (always 0 in recent version)
T Surface K Ground Surface Temperature
T Surface Diff K Difference of Ground Surface to Reference Surface
T Surface Change K/h Change of Ground Surface Temperature
q Surface g/kg Specific Humidity of Surface (availabe vapour)
uv Above Surface m/s Wind Speed at the First Grid Level above Ground Surface
Sensible Heat Flux W/m² Sensible Heat Flux into the Air (+: towards air)
Exchange Coef. Heat m²/s Exchange Coefficient for Heat between Surface and Air
Latent Heat Flux W/m² Sensible Heat Flux into the Air (+: towards air)
Soil Heat Flux W/m² Heat Flux into Soil (+: directed towards deeper layers)