Brightband Forecast Data Availability

Brightband forecast data will be made available as a zarr store. All forecasts have a 32 day lead time, 1.5 degree resolution, 64 ensemble members, and are initialized at 00Z. Every value is a daily mean. When read into xarray as a dataset, all forecasts have the following properties:

Dimensions and Coordinates

The forecasts will have five dimensions and coordinates:

member: 64 values (0 to 63), one per ensemble member
lead_time: a timedelta value representing the forecast step from a given forecast initialization date, in 32 daily steps from 1 to 32 days
latitude and longitude: coordinates for the 1.5 degree grid (121 latitudes from 90 to -90, 240 longitudes from 0 to 358.5)
level: 18 values representing pressure levels in hPa (1000, 925, 850, 700, 600, 500, 400, 300, 250, 200, 150, 100, 70, 50, 30, 10, 5, 2)

Each store holds a single initialization. init_time is a scalar coordinate, and valid_time (init_time + lead_time) is a coordinate along lead_time. A value at a given valid_time is the mean over the 24 hours ending at that time, i.e. the average of the 6-hourly states from valid_time - 18h to valid_time.

Variables

4D Variables

Six variables will have shape (member, lead_time, level, latitude, longitude). These variables are available at all pressure levels, except specific_humidity, which is available from 1000 to 150 hPa (its values at 100 hPa and above are NaN):

temperature
u_component_of_wind
v_component_of_wind
specific_humidity
geopotential
vertical_velocity

3D Surface and near-surface variables

There are 22 variables with shape (member, lead_time, latitude, longitude):

2m_temperature
2m_dewpoint_temperature
mean_total_precipitation_rate
10m_u_component_of_wind
10m_v_component_of_wind
100m_u_component_of_wind
100m_v_component_of_wind
mean_sea_level_pressure
soil_temperature_level_1
soil_temperature_level_2
soil_temperature_level_3
soil_temperature_level_4
volumetric_soil_water_layer_1
volumetric_soil_water_layer_2
volumetric_soil_water_layer_3
volumetric_soil_water_layer_4
sea_surface_temperature
sea_ice_cover
snow_depth
mean_surface_downward_short_wave_radiation_flux
mean_top_net_long_wave_radiation_flux

Metadata