This document species the NetCDF data contract for contrail forecast data as returned by the Contrail Forecast API method getGrids.
Data format
Forecast grids cover the whole globe and are returned in the netCDF4 format.
Dimensions
| Name | Type | Description |
|---|---|---|
longitude |
float32 |
-180 to +180 (inclusive), as configured in the request. Grid resolution is 0.25 degrees but may change in the future. |
latitude |
float32 |
-90 to +90 (inclusive), as configured in the request. Grid resolution is 0.25 degrees but may change in the future. |
flight_level |
int16 |
[270, 280, 290, 300, 310, 320, 330, 340, 350, 360, 370, 380, 390, 400, 410, 420, 430, 440], as configured in the request, in hectofeet. Flight levels are derived from pressure levels. |
time |
datetime64[ns] |
The requested real world forecast date and time, in UTC. |
forecast_reference_time |
datetime64[ns] |
Date and time at which the forecast was computed, rather than the time of forecast itself, in UTC. |
Variables
contrails (float32): (longitude, latitude, flight_level, time) continuous contrail forcing index values from [0 - 4].
Contrail forcing index values are inspired by turbulence forecast values.
Severity values can be interpreted as:
| Value | Interpretation |
|---|---|
| 0 | None |
| 1 | Low (light) |
| 2 | Moderate |
| 3 | High (severe) |
| 4 | Extreme |
Example
Example scaling translatesef_per_m to contrails index:
ds["contrails"] = ds["ef_per_m"].clip(min=1e7, max=2e9)
ds["contrails"] = ((ds["contrails"] - 1e7) / (2e9 - 1e7)) * 4ef_per_m to contrails index, see Energy Forcing Interpretation.