ACCESS-G: single-level "all-flds" fields
A number of raw and post-processed NWP products are available as outputs from the Australian Community Climate Earth-System Simulator (ACCESS) suite of Numerical Weather Prediction models which are run routinely by the Bureau National Operations Centre (NOC). This document describes the content of the ACCESS-G (version APS3) IDY25000.APS3.all-flds.slv.YYYYMMDDHH.HHH.surface, IDY25006.APS3.all-flds.slv.YYYYMMDDHH.HHH.surface, IDY25001.APS3.all-flds.slv.YYYYMMDDHH.HHH.surface, IDY25020.APS3.all-flds.slv.YYYYMMDDHH.HHH.surface and IDY25021.APS3.all-flds.slv.YYYYMMDDHH.HHH.surface series of products.
For background information about ACCESS please refer to the top-level ACCESS NWP technical data documentation page.
If you require further information or assistance about ACCESS NWP products contact the Bureau's Real-time Data Services Section.
Model summary
ACCESS-G covers a global domain, has a resolution of about 12 km and is run four times per day (00Z, 06Z, 12Z & 18Z basetimes) out to a forecast hour (HHH) of +240 (+84 for 06Z and 18Z). This model consists of both an assimilation and forecast component.
NWP data filename convention
All NWP files in this product series have names that conform to the following convention:
IDY25000.APS3.all-flds.slv.YYYYMMDDHH.HHH.surface.grb2 or
IDY25006.APS3.all-flds.slv.YYYYMMDDHH.HHH.surface.grb2 or IDY25006.APS3.all-flds.slv.YYYYMMDDHH.HHH.surface.nc4 or
IDY25001.APS3.all-flds.slv.YYYYMMDDHH.HHH.surface.grb2 or IDY25001.APS3.all-flds.slv.YYYYMMDDHH.HHH.surface.nc4 or
IDY25020.APS3.all-flds.slv.YYYYMMDDHH.HHH.surface.grb2 or
IDY25021.APS3.all-flds.slv.YYYYMMDDHH.HHH.surface.grb2 or IDY25021.APS3.all-flds.slv.YYYYMMDDHH.HHH.surface.nc4
where
YYYYMMDDHH | Base-date of model run in UTC time. YYYY = year, MM = month, DD = day, HH = hour |
---|---|
HHH | Forecast hour. A HHH of 000 is the analysis time-step. |
Horizontal grid geometries
Variant
[IDY code]
|
Resolution
[Lon x Lat]
|
Domain limits
[W to E, S to N (Lon x Lat grid points)]
|
Parameters
[NC Vars]
|
---|---|---|---|
IDY25000
|
0.176 by 0.117 | 0.088 to 359.912, -89.941 to 89.941 (2048 x 1536) | All |
IDY25006
|
0.176 by 0.117 | 64.951 to 184.482, -64.980 to 16.934 (681 x 700) | All |
IDY25001
|
0.176 by 0.117 | 95.010 to 169.893, -54.902 to 4.980 (427 x 512) | All |
IDY25020
|
0.176 by 0.117 | 0.088 to 359.912, -89.941 to 89.941 (2048 x 1536) | All |
IDY25021
|
0.176 by 0.117 | 95.010 to 169.893, -54.902 to 4.980 (427 x 512) | All |
Please note that
- Latitude values in GRIB and NetCDF files are ordered North to South while longitude values are ordered West to East.
- Longitudes always lie in the range 0.0 to 360.0 degrees. Longitudes can be transformed to lie between -180 and +180 degrees by subtracting 360 degrees from any longitude values greater than 180.
Time steps
- Forecast hours of single-level fields:
- 0 to 240 by 1
Parameters
The following fields are included in this product series. Note that the "G2 d.c.n" table column refers to a field's GRIB2 'discipline'.'parameterCategory'.'parameterNumber' metadata. For more information see GRIB2 format notes.
Single-level fields
G2 d.c.n | NetCDF var | Steps | G2 Units | NC Units | Description |
---|---|---|---|---|---|
0.2.22 | wndgust10m | All | m s-1 | m s-1 | 10m wind gust |
0.2.2 | u10 | All | m s-1 | m s-1 | 10m wind u component |
0.2.3 | v10 | All | m s-1 | m s-1 | 10m wind v component |
0.1.48 | accum_conv_rain | All | kg m-2 | kg m-2 | Accumulated convective rainfall |
0.1.14 | accum_conv_snow | All | kg m-2 | kg m-2 | Accumulated convective snowfall |
0.1.6 | accum_evap | All | kg m-2 | kg m-2 | Accumulated evaporation from land soil surface |
0.1.47 | accum_ls_rain | All | kg m-2 | kg m-2 | Accumulated large scale rainfall |
0.1.15 | accum_ls_snow | All | kg m-2 | kg m-2 | Accumulated large scale snowfall |
0.1.8 | accum_prcp | All | kg m-2 | kg m-2 | Accumulated precipitation |
0.5.3 | av_lwsfcdown | All | W m-2 | W m-2 | Average downwards longwave radiation at the surface |
0.4.7 | av_swsfcdown | All | W m-2 | W m-2 | Average downwards shortwave radiation at the surface |
0.4.7 | av_swirrtop | All | W m-2 | W m-2 | Average incoming shortwave radiation flux |
0.3.1 | av_mslp | All | Pa | Pa | Average mean sea level pressure |
0.2.3 | av10v | All | m s-1 | m s-1 | Average meridional wind at 10m |
0.5.5 | av_netlwsfc | All | W m-2 | W m-2 | Average net longwave radiation at surface |
0.4.9 | av_netswsfc | All | W m-2 | W m-2 | Average net shortwave radiation at surface |
0.5.4 | av_olr | All | W m-2 | W m-2 | Average outgoing longwave radiation |
0.1.206 | av_evap_sea | All | kg m-2 s-1 | kg m-2 s-1 | Average rate of evaporation over open sea |
0.0.0 | av_temp_scrn | All | K | K | Average screen level air temperature |
0.1.0 | av_qsair_scrn | All | kg kg-1 | kg kg-1 | Average screen level specific humidity |
0.0.10 | av_lat_hflx | All | W m-2 | W m-2 | Average surface latent heat flux |
0.2.18 | av_vwnd_strs | All | N m-2 | N m-2 | Average surface meridional wind stress |
0.0.11 | av_sens_hflx | All | W m-2 | W m-2 | Average surface sensible heat flux |
0.4.202 | av_sfc_sw_dif | All | W m-2 | W m-2 | Average surface shortwave diffuse radiation flux |
0.4.203 | av_sfc_sw_dir | All | W m-2 | W m-2 | Average surface shortwave direct radiation flux |
0.2.17 | av_uwnd_strs | All | N m-2 | N m-2 | Average surface zonal wind stress |
0.6.1 | av_ttl_cld | All | % | 1 | Average total cloud coverage |
0.1.207 | av_sfc_mois_flx | All | kg m-2 s-1 | kg m-2 s-1 | Average total surface moisture flux |
0.2.2 | av10u | All | m s-1 | m s-1 | Average zonal wind at 10m |
2.0.13 | canopy_wtr_cont | All | kg m-2 | kg m-2 | Canopy water content |
0.3.0 | conv_cldbse_pres | All | Pa | Pa | Convective cloud-base pressure |
0.3.0 | conv_cldtop_pres | All | Pa | Pa | Convective cloud-top pressure |
0.6.32 | fog_fraction | All | Numeric | 1 | Fog fraction |
0.6.5 | hi_cld | All | % | 1 | High cloud cover |
0.19.0 | vis_precip | All | m | m | Horizontal visibility (incl precip) |
2.0.0 | lnd_mask | All | 1 | 1 | Land mask |
0.6.3 | low_cld | All | % | 1 | Low cloud cover |
0.3.1 | mslp | All | Pa | Pa | Mean sea level pressure |
0.2.3 | v50r | 0 to 83 by 1, 84 to 240 by 3 | m s-1 | m s-1 | Meridional wind at the 50m rho level |
0.6.4 | mid_cld | All | % | 1 | Middle cloud cover |
0.3.18 | abl_ht | All | m | m | Planetary boundary layer height |
0.1.3 | precwtr | 0 to 83 by 1, 84 to 240 by 3 | kg m-2 | kg m-2 | Precipitable water |
0.19.0 | prob_vis_5km_ppt | All | 1 | 1 | Probability of horizontal visibility less than 5 km (incl precip) |
0.0.6 | dewpt_scrn | All | K | K | Screen level dewpoint temperature |
0.0.4 | tmax_scrn | All | K | K | Screen level max temperature |
0.0.5 | tmin_scrn | All | K | K | Screen level min temperature |
0.1.1 | rh2m | All | % | % | Screen level relative humidity w.r.t. water |
0.1.0 | qsair_scrn | All | kg kg-1 | kg kg-1 | Screen level specific humidity |
0.0.0 | temp_scrn | All | K | K | Screen level temperature |
2.0.206 | soil_mois_cont | All | kg m-2 | kg m-2 | Soil moisture available for transpiration |
2.0.3 | soil_mois | All | kg m-2 | kg m-2 | Soil moisture content in a layer |
2.0.3 | soil_mois | All | kg m-2 | kg m-2 | Soil moisture content layer 2 |
2.0.3 | soil_mois | All | kg m-2 | kg m-2 | Soil moisture content layer 3 |
2.0.3 | soil_mois | All | kg m-2 | kg m-2 | Soil moisture content layer 4 |
2.3.18 | soil_temp | All | K | K | Soil temperature in a layer |
2.3.18 | soil_temp | All | K | K | Soil temperature layer 2 |
2.3.18 | soil_temp | All | K | K | Soil temperature layer 3 |
2.3.18 | soil_temp | All | K | K | Soil temperature layer 4 |
0.0.10 | lat_hflx | All | W m-2 | W m-2 | Surface latent heat flux |
0.2.18 | vwnd_strs | All | N m-2 | N m-2 | Surface meridional wind stress |
0.3.0 | sfc_pres | All | Pa | Pa | Surface pressure |
2.0.1 | sfc_rough_len | All | m | m | Surface roughness length for momentum |
0.0.11 | sens_hflx | All | W m-2 | W m-2 | Surface sensible heat flux |
0.0.0 | sfc_temp | All | K | K | Surface temperature |
0.2.17 | uwnd_strs | All | N m-2 | N m-2 | Surface zonal wind stress |
0.3.5 | topog | All | gpm | gpm | Topography height above msl |
0.6.1 | ttl_cld | All | % | 1 | Total cloud cover |
0.2.2 | u50r | 0 to 83 by 1, 84 to 240 by 3 | m s-1 | m s-1 | Zonal wind at the 50m rho level |
Explanation of steps column terms
All | Parameter available at all time-steps |
---|---|
All but steps | Parameter available at all time-steps except as specified |
hhh... | Parameter available from fhr onward |
Notes on specific NWP file-formats
For technical notes about the GRIB2 encoding of ACCESS data, please refer to GRIB2 format notes. For technical notes about the NetCDF4 encoding of ACCESS data, please refer to NetCDF format notes.
Appendix A - Extended Field Descriptions
Extended description of single-level fields
G2 d.c.n | NetCDF var | Detailed description |
---|---|---|
0.2.22 | wndgust10m | Maximum three second wind speed (wind gust) at 10m above ground level. [m s-1] |
0.2.2 | u10 | Zonal (U) component of the wind velocity at 10m above ground level. [m s-1] |
0.2.3 | v10 | Meridional (V) component of the wind velocity at 10m above ground level. [m s-1] |
0.1.48 | accum_conv_rain | Accumulated total convective rainfall amount at the surface. [kg m-2] |
0.1.14 | accum_conv_snow | Accumulated total convective snow amount that falls to the surface. [kg m-2] |
0.1.6 | accum_evap | Accumulated evaporation from land soil surface. [kg m-2] |
0.1.47 | accum_ls_rain | Accumulated total large-scale rain amount at the surface. It does not include a convective contribution. [kg m-2] |
0.1.15 | accum_ls_snow | Accumulated total large-scale snow amount that falls to the surface. It does not include a convective contribution. [kg m-2] |
0.1.8 | accum_prcp | Accumulated total precipitation amount at the surface. This is the sum of rainfall and snowfall at the surface. [kg m-2] |
0.5.3 | av_lwsfcdown | Time-averaged downward flux of longwave radiation at the ground or ocean surface. [W m-2] |
0.4.7 | av_swsfcdown | Time-averaged downward flux of shortwave radiation at the ground or ocean surface. [W m-2] |
0.4.7 | av_swirrtop | Time-averaged incoming flux of shortwave radiation from the sun. [W m-2] |
0.3.1 | av_mslp | Time-averaged atmospheric pressure at mean sea level. [Pa] |
0.2.3 | av10v | Time-averaged meridional (V) component of the wind velocity at 10m above ground level. [m s-1] |
0.5.5 | av_netlwsfc | Time-averaged net downward (total downward minus upward) radiative longwave flux at the surface (ground or ocean). [W m-2] |
0.4.9 | av_netswsfc | Time-averaged net downward (total downward minus upward) radiative shortwave flux at the surface (ground or ocean). [W m-2] |
0.5.4 | av_olr | Time-averaged longwave radiation flux leaving the top of the atmosphere. [W m-2] |
0.1.206 | av_evap_sea | Time-averaged rate of evaporation over open sea. [kg m-2 s-1] |
0.0.0 | av_temp_scrn | Time-averaged atmospheric temperature at 1.5m above ground level (screen level). Calculated by integrating the similarity equations from the surface to 1.5m. [K] |
0.1.0 | av_qsair_scrn | Time-averaged atmospheric specific humidity at 1.5m above ground level (screen level). Calculated by integrating the similarity equations from the surface to 1.5m (surface value taken as saturated specific humidity at the surface temperature). [kg kg-1] |
0.0.10 | av_lat_hflx | Time-averaged latent heat flux at the surface (upward outgoing radiation values are positive). [W m-2] |
0.2.18 | av_vwnd_strs | Time-averaged north-south (meridional) component of the surface stress. [N m-2] |
0.0.11 | av_sens_hflx | Time-averaged sensible heat flux at the surface. This represents the time-averaged exchange of heat between the surface and the air by motion of air; also called “turbulent” heat flux. [W m-2] |
0.4.202 | av_sfc_sw_dif | Time-averaged downward diffuse shortwave radiation flux at the surface. [W m-2] |
0.4.203 | av_sfc_sw_dir | Time-averaged downward direct shortwave radiation flux at the surface. [W m-2] |
0.2.17 | av_uwnd_strs | Time-averaged east-west (zonal) component of the surface stress. [N m-2] |
0.6.1 | av_ttl_cld | Time-averaged total cloud coverage calculated with a maximum-random overlap assumption. [1] |
0.2.2 | av10u | Time-averaged zonal (U) component of the wind velocity at 10m above ground level. [m s-1] |
2.0.13 | canopy_wtr_cont | Quantity of water held in the canopy. [kg m-2] |
0.3.0 | conv_cldbse_pres | Atmospheric pressure at the convective cloud base. [Pa] |
0.3.0 | conv_cldtop_pres | Atmospheric pressure at the convective cloud top. [Pa] |
0.6.32 | fog_fraction | Estimated fog fraction at 1.5m above ground level. Please note that this diagnostic has not be tuned for Australian conditions and does not include dynamic atmospheric particulate densities, which is an important part of the algorithm used to generate this field. At this stage this field is considered experimental and should be used with due caution. [1] |
0.6.5 | hi_cld | High cloud cover, calculated under maximum overlap assumption between ICAO 500hPa and 150hPa levels (5574m and 13608m above mean sea level). [1] |
0.19.0 | vis_precip | Estimated horizontal visibility at approximately 1.5m above ground level, including reduction due to precipitation. Calculated similarly to grib code 20.229. At this stage this field is considered experimental and should be used with due caution. [m] |
2.0.0 | lnd_mask | Land mask (takes the value 1 or -1 if any land is in the grid box, otherwise 0). [1] |
0.6.3 | low_cld | Low cloud cover, calculated under maximum overlap assumption between ICAO 1000hPa and 800Pa levels (111m and 1949m above mean sea level). [1] |
0.3.1 | mslp | Atmospheric pressure at mean sea level. [Pa] |
0.2.3 | v50r | Meridional (V) component of the "50m" rho-level winds (the hybrid- height level with an eta value of 0.0007947). This is the same field as level index 2 rho-level V but has been made available as a single-level "destaggered" field for convenience. [m s-1] |
0.6.4 | mid_cld | Middle cloud cover, calculated under maximum overlap assumption between ICAO 800hPa and 500Pa levels (1949m and 5574m above mean sea level). [1] |
0.3.18 | abl_ht | Height above ground level of the top of the planetary boundary layer (i.e. boundary layer depth). [m] |
0.1.3 | precwtr | Total column precipitable water. [kg m-2] |
0.19.0 | prob_vis_5km_ppt | Probability of horizontal visibility at approximately 1.5m above ground level being less than 5 km with precipitation taken into account. Please note that this diagnostic has not be tuned for Australian conditions and does not include dynamic atmospheric particulate densities, which is an important part of the algorithm used to generate this field. At this stage this field is considered experimental and should be used with due caution. [1] |
0.0.6 | dewpt_scrn | Dewpoint temperature at 1.5m above ground level (screen level). [K] |
0.0.4 | tmax_scrn | Maximum (over a time window) atmospheric air temperature at 1.5m above ground level (screen level). [K] |
0.0.5 | tmin_scrn | Minimum (over a time window) atmospheric air temperature at 1.5m above ground level (screen level). [K] |
0.1.1 | rh2m | Relative humidity at 1.5m above ground level (screen level). Calculated as 100*water_vapour_pressure/saturation_partial_pressure_of_water_vapour where the the saturation partial pressure of water vapour represents the saturation vapour pressure over liquid water for temperatures above the triple point, over ice for temperatures 20 degrees below the triple point, and a linear combination of the two for temperatures in-between. [%] |
0.1.0 | qsair_scrn | Atmospheric specific humidity at 1.5m above ground level (screen level). Calculated by integrating the similarity equations from the surface to 1.5m (surface value taken as saturated specific humidity at the surface temperature). [kg kg-1] |
0.0.0 | temp_scrn | Atmospheric temperature at 1.5m above ground level (screen level). Calculated by integrating the similarity equations from the surface to 1.5m. [K] |
2.0.206 | soil_mois_cont | A measure of soil moisture in the root-zone available for transpiration by plants. The rootzone extends to a depth of about 1m below the soil surface. This field is defined to be the difference between the actual unfrozen soil moisture and the wilting point to the rootzone depth. Note: if the actual soil moisture in a layer falls below the wilting point then this field can be negative, which implies water needs to added for transpiration to take place. [kg m-2] |
2.0.3 | soil_mois | Total (frozen and unfrozen) soil moisture content in soil layer 1 (surface to 0.1m depth). [kg m-2] |
2.0.3 | soil_mois | Total (frozen and unfrozen) soil moisture content in soil layer 2 (0.10m to 0.35m depth). [kg m-2] |
2.0.3 | soil_mois | Total (frozen and unfrozen) soil moisture content in soil layer 3 (0.35m to 1.00m depth). [kg m-2] |
2.0.3 | soil_mois | Total (frozen and unfrozen) soil moisture content in soil layer 4 (1.00m to 3.00m depth). [kg m-2] |
2.3.18 | soil_temp | Mean soil/land-ice temperature within soil layer 1 (surface to 0.1m depth). [K] |
2.3.18 | soil_temp | Mean soil/land-ice temperature within soil layer 1 (0.10m to 0.35m depth). [K] |
2.3.18 | soil_temp | Mean soil/land-ice temperature within soil layer 1 (0.35m to 1.00m depth). [K] |
2.3.18 | soil_temp | Mean soil/land-ice temperature within soil layer 1 (1.00m to 3.00m depth). [K] |
0.0.10 | lat_hflx | Latent heat flux at the surface (upward outgoing radiation values are positive). [W m-2] |
0.2.18 | vwnd_strs | The north-south (meridional) component of the surface stress. [N m-2] |
0.3.0 | sfc_pres | Atmospheric pressure at the surface. [Pa] |
2.0.1 | sfc_rough_len | Surface roughness length for momentum in air. A constant of integration in the logarithmic wind profile. In this diagnostic, the effective roughness of subgrid model orography has been neglected. [m] |
0.0.11 | sens_hflx | Surface sensible heat flux. This represents the exchange of heat between the surface and the air by motion of air; also called “turbulent” heat flux. [W m-2] |
0.0.0 | sfc_temp | Temperature of the land or sea/sea-ice surface. On land points this is the surface "skin" temperature. On ice-free sea points it is the temperature of the sea surface, and on sea points with ice it is a gridbox mean given by: [(ice fraction)*(temperature of top ice layer computed by the atmosphere surface/boundary layer scheme)] + [(1 - ice fraction)*(freezing point of sea water)]. [K] |
0.2.17 | uwnd_strs | The east-west (zonal) component of the surface stress. [N m-2] |
0.3.5 | topog | Height of topography (above the geoid). [gpm] |
0.6.1 | ttl_cld | Total cloud coverage calculated with a maximum-random overlap assumption. [1] |
0.2.2 | u50r | Zonal (U) component of the "50m" rho-level winds (the hybrid-height level with an eta value of 0.0007947). This is the same field as level index 2 rho-level U but has been made available as a single-level "destaggered" field for convenience. [m s-1] |
Please note:
- Fields in the above tables are listed in the same order as shown in the Parameters section of this document.
- Units in the above table refer to NetCDF fields. In some cases the GRIB2 equivalent field has had values scaled/offset to convert to SI units for WMO GRIB2 compliance.
- The nature of fields can not always be deduced easily from their NetCDF variable names. In particular the 'soil_mois_cont' variable name could be misleading. It is always safest to refer to the detailed description of a parameter.
- All accumulated fields are accumulated from the start of the model assimilation window. Hence any of these fields can be non-zero at the model base-time (which is a time-step at the center of the assimilation window).
- Maximum and minimum screen-level temperatures represent a maximum/minimum value over the period from the last model output time-step to the field's nominal forecast-hour.
- The geoid surface is at approximately mean sea level.