orog

Surface Altitude (m)

The parameter is the altitude of the Earth's surface or the geometric height of the surface above the geoid. It is the lower boundary of the UK Met Office Unified Model over land and describes the physical features and elevation variations across landscapes. It is also known as surface geopotential height. This parameter does not vary in time.

BARPA-C/AUST-04/fx, BARPA-R/AUS-15/fx, BARPA-R/AUST-15/fx

sftlf

Percentage of the grid cell occupied by land (including lakes) (%)

Percentage of the modelling grid box occupied by land, including lakes.

BARPA-C/AUST-04/fx, BARPA-R/AUS-15/fx, BARPA-R/AUST-15/fx

pr

Precipitation (kg m-2 s-1)

This parameter is the rate of total precipitation, comprising rain and snow, at the surface. The parameter is the rate the precipitation would have if it were spread evenly over the model grid cell. Since 1 kg of water spread evenly over 1 square-metre of surface has 1 mm depth, the units of kg m-2 s-1 are equivalent to mm per second. In the case where the UK Met Office Unified Model was set up with a horizontal grid spacing of 10 km or longer, the parameter combines the contributions from the convection scheme and the cloud scheme. The rate of precipitation produced by the convection scheme is available in the parameter prc, and that produced by the cloud scheme is available in the parameter prra.

BARPA-C/AUST-04/1hr, BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/1hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

prc

Convective Precipitation (kg m-2 s-1)

This parameter is the rate of precipitation, comprising rain and snow, at the surface, generated by the convection parameterisation scheme in the UK Met Office Unified Model when set up with a horizontal grid spacing of 10 km or longer. The convection scheme estimates sub-grid scale convection and precipitation at spatial scales smaller than the grid length. This differs from the precipitation generated by the cloud scheme in the Unified Model, which describes the formation and dissipation of clouds and precipitation due to changes in atmospheric conditions simulated at spatial scales of the grid cell or longer. The parameter is the rate the precipitation would have if it were spread evenly over the model grid cell. Since 1 kg of water spread evenly over 1 square-metre of surface has 1 mm depth, the units of kg m-2 s-1 are equivalent to mm per second. The total precipitation rate that combines the contributions from the convection scheme and the cloud scheme is available in the parameter pr. The contribution simulated by the cloud scheme is available in the parameter prra.

BARPA-R/AUS-15/1hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

prga

Graupel Sediment Rate (kg kg-1 s-1)

This parameter is the rate of graupel at the surface, estimated by the cloud scheme in the UK Met Office Unified Model. Graupels forms when supercooled water droplets freeze onto falling snowflakes. The precipitation was generated as the result of changes in atmospheric conditions simulated at the spatial scales of the model grid cell or longer. The parameter is the rate the precipitation would have if it were spread evenly over the model grid cell. Since 1 kg of water equivalent spread evenly over 1 square-metre of surface has 1 mm depth, the units of kg m-2 s-1 are equivalent to mm per second.

BARPA-C/AUST-04/1hr, BARPA-C/AUST-04/20min

prhmax

Daily Maximum Hourly Precipitation Rate (kg m-2 s-1)

This parameter is the daily maximum hourly rate of total precipitation, comprising rain and snow, at the surface. The parameter is the rate the precipitation would have if it were spread evenly over the model grid cell. Since 1 kg of water spread evenly over 1 square-metre of surface has 1 mm depth, the units of kg m-2 s-1 are equivalent to mm per second. In the case where the UK Met Office Unified Model was set up with a horizontal grid spacing of 10 km or longer, the parameter combines the contributions from the convection scheme and the cloud scheme.

BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

prra

Large Scale Rainfall Rate (kg m-2 s-1)

This parameter is the rate of precipitation, comprising rain and snow, at the surface, generated by the cloud scheme in the UK Met Office Unified Model. The precipitation was generated as the result of changes in atmospheric conditions simulated at the spatial scales of the model grid cell or longer. The parameter is the rate the precipitation would have if it were spread evenly over the model grid cell. Since 1 kg of water spread evenly over 1 square-metre of surface has 1 mm depth, the units of kg m-2 s-1 are equivalent to mm per second. The total precipitation rate that combines both rain and snow is available in the parameter pr.

BARPA-C/AUST-04/1hr, BARPA-C/AUST-04/20min

prsn

Snowfall Flux (kg m-2 s-1)

This parameter is the rate of snow at the surface, generated by the cloud scheme in the UK Met Office Unified Model. The precipitation was generated as the result of changes in atmospheric conditions simulated at the spatial scales of the model grid cell or longer. The parameter is the rate the precipitation would have if it were spread evenly over the model grid cell. Since 1 kg of water equivalent spread evenly over 1 square-metre of surface has 1 mm depth, the units of kg m-2 s-1 are equivalent to mm per second. The total precipitation rate that combines both rain and snow is available in the parameter pr.

BARPA-C/AUST-04/1hr, BARPA-C/AUST-04/20min, BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/1hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

prsnmax

Hourly Maximum Snowfall Flux (kg m-2 s-1)

This parameter is the hourly maximum rate of snow at the surface. The parameter is the rate the precipitation would have if it were spread evenly over the model grid cell. Since 1 kg of water equivalent spread evenly over 1 square-metre of surface has 1 mm depth, the units of kg m-2 s-1 are equivalent to mm per second.

BARPA-C/AUST-04/1hr

prw

Water Vapor Path (kg m-2)

This parameter is the integrated mass of water vapour in a vertical column of the atmosphere, extending from the Earth's surface to the top of the atmosphere. It is useful for predicting precipitation and studying humidity levels.

BARPA-C/AUST-04/1hr, BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/1hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

This parameter is likely very similar to PW. Some difference may be due to the range of vertical levels across which integration was made.

ares

Aerodynamic Resistance (s m-1)

This parameter is the aerodynamic resistance in an atmospheric model. It is a measure of how easily air can move between the land surface and the first atmospheric model level. The resistance depends on wind speed, surface roughness, and atmospheric stability, and indicates how different land surfaces interact with the atmosphere.

BARPA-C/AUST-04/6hr

cw

Total Canopy Water Storage (kg m-2)

This parameter is a measure of the amount of water stored in the canopy for each model grid box, expressed in the units of kg m-2 (per unit area). It does not include soil moisture or precipitation.

BARPA-C/AUST-04/6hr

evspsbl

Evaporation Including Sublimation and Transpiration (kg m-2 s-1)

The rate of evapotranspiration from the surface to the atmosphere. This includes evaporation from the sea surface, evaporation from the soil surface, transpiration from plants and evaporation from the vegetative canopy.

BARPA-C/AUST-04/1hr, BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/1hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

evspsblpot

Potential Evapotranspiration (kg m-2 s-1)

This parameter is the potential evapotranspiration (PET), the ET that would occur if the soil and vegetation are saturated. It is a flux parameter to indicate it is a quantity expressed as per unit area, per second. The PET scales with the friction velocity for each tile type (e.g., grass, shrub, broadleaf tree, bare soil), which depends on the canopy heights etc. PET is computed by the model for each tile type and the average across the tiles are computed and published. It is of note that the energy constraint is not imposed on the calculation of this diagnostic in the model, which is different from using the Penman-Monteith equation. In other words, the PET diagnostic is simply driven by a surface to atmosphere humidity difference.

BARPA-C/AUST-04/1hr, BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/1hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

mrfso

Soil Frozen Water Content (kg m-2)

The total mass of frozen water per unit area summed over the four soil layers. This parameter has two spatial coordinates. There are four soil levels, representing a total depth of (0-3m) below the surface. Units are kg/m2. This parameter is valid on land points only.

BARPA-C/AUST-04/6hr, BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/6hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

mrfsol

Frozen Water Content of Soil Layer (kg m-2)

The total mass of frozen water per unit area in each soil layer. This parameter has three spatial coordinates, with the third representing the soil level. There are four soil levels, representing (0-10cm), (10-35cm), (35cm-1m) and (1m-3m) below the surface. Units are kg/m2. This parameter is valid on land points only.

BARPA-C/AUST-04/6hr, BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/6hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

mrfsos

Frozen Water Content in Upper Portion of Soil Column (kg m-2)

The mass of frozen moisture per unit area in the top soil layer. Units are kg/m2. The top soil layer represents the top 10-cm below the surface.

BARPA-C/AUST-04/1hr, BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/1hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

mrro

Total Runoff (kg m-2 s-1)

The total rate of runoff per unit area, precipitation which hits the ground and moves away rather than being absorbed by the soil. Units are kg/m2/s. This parameter represents the sum of both surface and subsurface runoff. A river routing model has not been applied, so runoff is removed from the system as soon as it forms. This parameter is valid on land points only.

BARPA-C/AUST-04/1hr, BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/6hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

mrros

Surface Runoff (kg m-2 s-1)

The rate of surface runoff per unit area, precipitation which hits the ground and moves away rather than being absorbed by the soil. Units are kg/m2. This parameter represents the surface runoff only. A river routing model has not been applied, so runoff is removed from the system as soon as it forms. This parameter is valid on land points only.

BARPA-C/AUST-04/1hr, BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/6hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

mrso

Total Soil Moisture Content (kg m-2)

The total mass of moisture summed over the four soil layers. This parameter has two spatial coordinates. There are four soil levels, representing a total depth of (0-3m) below the surface. Units are kg/m2. Divide by the soil level depths (3 m) and by the density of water (1000 kg/m3) to convert into the moisture fraction. This parameter is valid on land points only.

BARPA-C/AUST-04/6hr, BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/6hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

mrsol

Total Water Content of Soil Layer (kg m-2)

The total mass of moisture per unit area in each soil layer. This parameter has three spatial coordinates, with the third representing the soil level. There are four soil levels, representing (0-10cm), (10-35cm), (35cm-1m) and (1m-3m) below the surface. Units are kg/m2. Divide by the soil level depths (0.1, 0.25, 0.65 and 2 m) and by the density of water (1000 kg/m3) to convert into the moisture fraction. This parameter is valid on land points only.

BARPA-C/AUST-04/6hr, BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/6hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

mrsos

Moisture in Upper Portion of Soil Column (kg m-2)

The mass of moisture per unit area in the top soil layer. Units are kg/m2. The top soil layer represents the top 10-cm below the surface. This parameter is valid on land points only.

BARPA-C/AUST-04/1hr, BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/1hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

sfcMoisflx

Surface Total Moisture Flux (kg m-2 s-1)

The total moisture flux per unit area between the surface and the atmosphere. This parameter does not include precipitation.

BARPA-C/AUST-04/6hr

sic

Sea Ice Area Fraction (%)

This parameter indicates how much of a given ocean area is covered by sea ice. It is expressed as a fraction, ranging from 0 (no ice) to 1 (completely ice-covered).

BARPA-C/AUST-04/6hr, BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/6hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

snd

Snow Depth (m)

This parameter represents the instantaneous depth of snow on top of the land surface. It has units of metres. It is valid on land grid-cells only.

BARPA-C/AUST-04/6hr, BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/6hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

snm

Surface Snow Melt (kg m-2 s-1)

This is the rate at which the snow mass per unit area on top of the land surface melts. It has units of kg/m2/s. It is valid on land grid-cells only.

BARPA-C/AUST-04/6hr, BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/6hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

snw

Surface Snow Amount (kg m-2)

This parameter is the mass of snow per unit area present on the land surface. It has units of kg/m2. It is present on land grid-cells only.

BARPA-C/AUST-04/6hr, BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/6hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

soildrainage

Drainage out of Soil Model (kg m-2 s-1)

This parameter is the rate of water drains freely from the bottom of the soil column in the Joint UK Land Simulator (JULES). The version of the model does not include a water table or groundwater flow. This parameter is valid on land grid-cells only.

BARPA-C/AUST-04/6hr

throughfall

Canopy Throughfall Rate (kg m-2 s-1)

The rate per unit area that water falls through the vegetative canopy. Units are kg/m2/s.

BARPA-C/AUST-04/6hr

ts* (ts, tsmean)

Surface Temperature (K)

This parameter is the temperature of the land or sea/sea-ice surface of the Earth. Over land, this is the surface skin temperature. On ice-free sea areas, it is the temperature of sea surface. On sea areas with ice, it is a ice fraction weighted sum of temperature of top ice layer and freezing point of sea water. It has units of kelvin (K) and can be converted to degrees Celsius by subtracting 273.15. This parameter is available as instantaneous and time-averaged quantities.

BARPA-C/AUST-04/1hr, BARPA-C/AUST-04/20min, BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/1hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

tsl

Temperature of Soil (K)

This parameter is the temperature of the soil at 4 soil layers. The model has a four-layer representation of soil column. The depth of first (topmost) soil layer is 0 to 10 cm where the surface is at 0 cm. The second layer is 10 to 35 cm, with a thickness of 20 cm. The third layer is 35 cm to 1 metre, with a thickness of 65 cm. The last (deepest) layer is 1 metre to 3 metres, with a thickness of 2 metre. It has units of kelvin (K) and can be converted to degrees Celsius by subtracting 273.15.

BARPA-C/AUST-04/6hr, BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/6hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

z0

Surface Roughness Length (m)

This parameter quantifies the roughness of the Earth's surface due to various roughness elements such as vegetation and terrain features, which affects the flow of air over it. It represents the height above the ground at which the wind speed theoretically becomes zero due to the surface's roughness element. The parameter can be useful for predicting how wind speed changes with height.

BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

hus* (hus10, hus100, hus150, hus1000, hus150, hus20, hus200, hus250, hus30, hus300, hus400, hus50, hus500, hus600, hus70, hus700, hus750, hus800, hus850, hus900, hus925, hus950, hus975)

Specific Humidity (1)

This parameter is the ratio of the mass of water vapour to the total mass of air, expressed as kilogram of water vapour per kilogram of moist air. The total mass of moist air includes the mass of the dry air, water vapour, cloud liquid and ice, rain and snow. This is available at multiple pressure levels in the atmosphere.

BARPA-C/AUST-04/3hr, BARPA-C/AUST-04/6hr, BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/6hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

omega500

Downward Air Velocity in pressure coordinates (Pa s-1)

This parameter is the speed of air motion in the upward or downward direction. It is expressed with a pressure-based vertical coordinate system and has units of pascals per second. Since atmospheric pressure decreases with height, positive values corresponds downward motion and negative values indicate upward motion.

BARPA-R/AUS-15/6hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

This parameter is identical to wap500.

radrefl1km

Radar reflectivity at 1km altitude (dBZ)

This parameter represents the radar reflectivity at an altitude of 1 km above the surface. This altitude is typically used for comparisons between model simulated reflectivity with network radars. The units are dBZ and has a lower bound of -40 dBZ when there is no cloud or precipitation. The reflectivity assumes contributions from rain, snow, graupel and liquid cloud.

BARPA-C/AUST-04/20min

ta* (ta10, ta100, ta1000, ta150, ta20, ta200, ta250, ta30, ta300, ta400, ta50, ta500, ta600, ta70, ta700, ta750, ta800, ta850, ta900, ta925, ta950, ta975)

Air Temperature (K)

This parameter refers to the temperature in the atmosphere. It has units of kelvin (K) and can be converted to degrees Celsius by subtracting 273.15. This parameter is available on multiple pressure levels through the atmosphere.

BARPA-C/AUST-04/3hr, BARPA-C/AUST-04/6hr, BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/6hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

ta*m (ta100m, ta1500m, ta150m, ta200m, ta250m, ta50m)

Air Temperature (K)

This parameter is the temperature in the atmosphere. It has units of kelvin (K) and can be converted to degrees Celsius by subtracting 273.15. This parameter is available at multiple geometric heights above the surface of the Earth.

BARPA-C/AUST-04/1hr, BARPA-C/AUST-04/20min, BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/1hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

ua* (ua10, ua100, ua1000, ua150, ua20, ua200, ua250, ua30, ua300, ua400, ua50, ua500, ua600, ua70, ua700, ua750, ua800, ua850, ua900, ua925, ua950, ua975)

Eastward Wind (m s-1)

This parameter is the northward component of the wind, at a pressure level in the atmosphere, as given in the variable name. When positive, it is the horizontal speed of air moving towards the east, and when negative, it is towards the west. It can be combined with the northward component of wind (va<NNN>) to give the speed and direction of the horizontal wind. This parameter is available on multiple pressure levels through the atmosphere.

BARPA-C/AUST-04/3hr, BARPA-C/AUST-04/6hr, BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/6hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

ua*m (ua100m, ua1500m, ua150m, ua200m, ua250m, ua50m)

Eastward Wind (m s-1)

This parameter is the eastward component of the wind, at a height of some metres above the surface, as given in the variable name. When positive, it is the horizontal speed of air moving towards the east, and when negative, it is towards the west. It can be combined with the northward component of wind (va<NNN>m) to give the speed and direction of the horizontal wind. This parameter is available at multiple geometric heights above the surface of the Earth.

BARPA-C/AUST-04/1hr, BARPA-C/AUST-04/20min, BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/1hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

va* (va10, va100, va1000, va150, va20, va200, va250, va30, va300, va400, va50, va500, va600, va70, va700, va750, va800, va850, va900, va925, va950, va975)

Northward Wind (m s-1)

This parameter is the northward component of the wind, at a pressure level in the atmosphere, as given in the variable name. When positive, it is the horizontal speed of air moving towards the north, and when negative, it is towards the south. It can be combined with the eastward component of wind (ua<NNN>) to give the speed and direction of the horizontal wind. This parameter is available on multiple pressure levels through the atmosphere.

BARPA-C/AUST-04/3hr, BARPA-C/AUST-04/6hr, BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/6hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

va*m (va100m, va1500m, va150m, va200m, va250m, va50m)

Northward Wind (m s-1)

This parameter is the northward component of the wind, at a height of some metres above the surface, as given in the variable name. When positive, it is the horizontal speed of air moving towards the north, and when negative, it is towards the south. It can be combined with the eastward component of wind (ua<NNN>m) to give the speed and direction of the horizontal wind. This parameter is available at multiple geometric heights above the surface of the Earth.

BARPA-C/AUST-04/1hr, BARPA-C/AUST-04/20min, BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/1hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

wa* (wa10, wa100, wa150, wa1000, wa150, wa20, wa200, wa250, wa30, wa300, wa400, wa50, wa500, wa600, wa70, wa700, wa750, wa800, wa850, wa900, wa925, wa950, wa975)

Upward Air Velocity (m s-1)

This parameter is the speed of air motion in the upward or downward direction. It is expressed with a geometric vertical coordinate system and has units of metres per second, and is different from wap<NNN> that is expressed in a pressure-based vertical coordinate system. Positive values correspond upward motion and negative values indicate upward motion.

BARPA-C/AUST-04/3hr, BARPA-C/AUST-04/6hr, BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/6hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

wap* (wap10, wap100, wap150, wap1000, wap150, wap20, wap200, wap250, wap30, wap300, wap400, wap50, wap500, wap600, wap70, wap700, wap750, wap800, wap850, wap900, wap925, wap950, wap975)

Upward air velocity in pressure/second (Pa s-1)

This parameter is the speed of air motion in the upward or downward direction. It is expressed with a pressure-based vertical coordinate system and has units of pascals per second, and is different from wa<NNN> that is expressed in a geometric vertical coordinate system. Since atmospheric pressure decreases with height, positive values corresponds downward motion and negative values indicate upward motion.

BARPA-C/AUST-04/3hr, BARPA-C/AUST-04/6hr, BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon

zg* (zg10, zg100, zg150, zg1000, zg150, zg20, zg200, zg250, zg30, zg300, zg400, zg50, zg500, zg600, zg70, zg700, zg750, zg800, zg850, zg900, zg925, zg950, zg975)

Geopotential Height (m)

This parameter is the height of a specific pressure level above mean sea level. It is commonly used for analysis of weather patterns. Synoptic charts of geopotential height plotted at constant pressure levels can be used to identify weather systems such as troughs, ridges, cyclones, and anticyclones. The parameter can be converted to geopotential, which is the gravitational potential energy of a unit mass relative to mean sea level, multiplying with the Earth's gravitational acceleration g of 9.80665 m s-2.

BARPA-C/AUST-04/3hr, BARPA-C/AUST-04/6hr, BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/6hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

zmla

Height of Boundary Layer (m)

This parameter is the depth of the atmosphere boundary layer, in units of m. The boundary layer is the lowest part of the atmosphere that directly interacts with the Earth's surface.

BARPA-C/AUST-04/1hr, BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/1hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

ztp

Tropopause height (m)

Height of the model identified tropopause, in units of m. The tropopuse height is the boundary between the troposphere and the stratosphere. Thunderstorms and convection are capped by the tropopause so its height can indicate how tall are the storms. Further, jet streams often flow near the tropospause.

BARPA-C/AUST-04/1hr

clh

High Level Cloud Fraction (%)

This parameter is the proportion of a grid box covered by cloud occurring in the high levels of the troposphere between ICAO (International Civil Aviation Organization) 500 and 150 hPa levels (5574m and 13608m above mean sea level). It is calculated from cloud at the appropriate model levels between this range. The parameter is calculated under maximum-random overlap assumption.

BARPA-C/AUST-04/1hr, BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/1hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

clivi

Ice Water Path (kg m-2)

This parameter is the total mass of ice particles suspended in clouds within a vertical column of the atmosphere, represented over a unit area. This parameter has units of kg/m2.

BARPA-C/AUST-04/1hr, BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/1hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

cll

Low Level Cloud Fraction (%)

This parameter is the proportion of a grid box covered by cloud occurring in the lower levels of the troposphere between ICAO (International Civil Aviation Organization) 1000hPa and 800Pa levels (111m and 1949m above mean sea level). It is calculated from cloud at the appropriate model levels between this range. The parameter is calculated under maximum-random overlap assumption.

BARPA-C/AUST-04/1hr, BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/1hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

clm

Mid Level Cloud Fraction (%)

This parameter is the proportion of a grid box covered by cloud occurring in the middle levels of the troposphere between ICAO (International Civil Aviation Organization) 800hPa and 500Pa levels (1949m and 5574m above mean sea level). It is calculated from cloud at the appropriate model levels between this range. The parameter is calculated under maximum-random overlap assumption.

BARPA-C/AUST-04/1hr, BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/1hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

clt

Total Cloud Cover Percentage (%)

This parameter is the proportion of a grid box covered by cloud occurring at all model levels through the atmosphere. The parameter is calculated under maximum-random overlap assumption.

BARPA-C/AUST-04/1hr, BARPA-C/AUST-04/20min, BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/1hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

clwvi

Condensed Water Path (kg m-2)

The vertical integral of liquid water mass contained in clouds. This parameter has units of kg/m2.

BARPA-C/AUST-04/1hr, BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/1hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

coltotdrym

Total column dry mass (kg m-2)

This parameter is the total mass of dry air, excluding water vapour, precipitation and cloud condensates like cloud water or cloud ice, in a vertical column of the atmosphere. It has units of kg/m2. Together with coltotwetm parameter, it is useful for studying the movement of moisture and gases in the atmosphere.

BARPA-C/AUST-04/1hr

coltotwetm

Total column wet mass (kg m-2)

This parameter is the total mass of all atmospheric constituents, including water vapour, precipitation, cloud condensates and dry air, in a vertical column of the atmosphere. It has units of kg/m2. It is useful for studying the movement of mass in the atmosphere.

BARPA-C/AUST-04/1hr

helicity* (helicity, helicitymax, helicitymin)

Updraft Helicity (2000-5000m) (m2 s-2)

This parameter is a measure of the rotation within a storm's updraft, combining vertical velocity (updraft speed) and vertical vorticity (rotation). This is calculated by integrating the product of updraft speed and vorticity over a specific depth of the atmosphere 2-5 km AGL. It is useful for identifying areas where strong, rotating updrafts are likely to occur, which is associated with severe weather events like supercells and tornadoes. The parameter is available as instantaneous, time-maximum and time-minimum quantities.

BARPA-C/AUST-04/1hr, BARPA-C/AUST-04/20min

maxcolrefl

Maximum Radar Reflectivity in the grid column due to all hydrometeors (dBZ)

This parameter represents the maximum value of radar reflectivity in each model column, defined as extending from the surface to the top of the model (40-80 km). It includes contributions from all hydrometeors, namely rain, snow, graupel and liquid cloud. Its units are dBZ and a minimum value of -40 dBZ is set where there is no cloud or precipitation.

BARPA-C/AUST-04/1hr

maxcolwa

Maximum vertical wind speed in column (m s-1)

This parameter is the maximum value of speed of vertical air motion in each model column. It is expressed with a geometric vertical coordinate system and has units of metres per second. Positive values correspond upward motion and negative values indicate upward motion.

BARPA-C/AUST-04/1hr

qfluxu

Eastward column-integrated moisture flux (kg m-1 s-1)

This parameter is the movement of water vapour in the atmosphere from west to east, integrated over the vertical column of the atmosphere. It is useful for understanding the transport of moisture across regions, affecting weather patterns and precipitation.

BARPA-C/AUST-04/3hr

qfluxv

Northward column-integrated moisture flux (kg m-1 s-1)

This parameter is the movement of water vapour in the atmosphere from south to north, integrated over the vertical column of the atmosphere. It is useful for understanding the transport of moisture across regions, affecting weather patterns and precipitation.

BARPA-C/AUST-04/3hr

rlds

Surface Downwelling Longwave Radiation (W m-2)

This parameter is the amount of longwave (infrared) radiation that.

BARPA-C/AUST-04/1hr, BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/1hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

rldscs

Surface Downwelling Clear-Sky Longwave Radiation (W m-2)

This parameter is the amount of longwave (infrared) radiation that is emitted by the atmosphere and reaches the Earth's surface under clear-sky conditions. It is referred as a flux parameter to indicate it is a quantity expressed as per unit area.

BARPA-C/AUST-04/1hr, BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/1hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

rlus

Surface Upwelling Longwave Radiation (W m-2)

This parameter is the amount of longwave (infrared) radiation emitted by the Earth's surface and the reflected atmospheric downward longwave radiation. It is referred as a flux parameter to indicate it is a quantity expressed as per unit area.

BARPA-C/AUST-04/1hr, BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/1hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

rluscs

Surface Upwelling Clear-Sky Longwave Radiation (W m-2)

This parameter is the amount of longwave (infrared) radiation emitted by the Earth's surface and the reflected atmospheric downward longwave radiation under clear-sky conditions. It is referred as a flux parameter to indicate it is a quantity expressed as per unit area.

BARPA-C/AUST-04/1hr, BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/1hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

rlut

TOA Outgoing Longwave Radiation (W m-2)

This parameter is the amount of longwave (infrared) radiation emitted into space by the Earth and its atmosphere. It is also called the outgoing longwave radiation or OLR. It is referred as a flux parameter to indicate it is a quantity expressed as per unit area.

BARPA-C/AUST-04/1hr, BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/1hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

rlutcs

TOA Outgoing Clear-Sky Longwave Radiation (W m-2)

This parameter is the amount of longwave (infrared) radiation emitted into space by the Earth and its atmosphere without the interference of clouds. It is referred as a flux parameter to indicate it is a quantity expressed as per unit area.

BARPA-C/AUST-04/1hr, BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/1hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

rsds

Surface Downwelling Shortwave Radiation (W m-2)

This parameter is the shortwave radiation from the Sun, incident on the Earth's surface. It is referred as a flux parameter to indicate it is a quantity expressed as per unit area. It is a combination of direct and diffused solar radiation. Its direct component has not accounted for the solar zenith angle. This parameter can be treated as an estimate of global horizontal irradiance (GHI).

BARPA-C/AUST-04/1hr, BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/1hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

rsdscs

Surface Downwelling Clear-Sky Shortwave Radiation (W m-2)

This parameter is the amount of solar radiation that reaches the Earth's surface under clear-sky conditions, without interference from clouds. It is a flux parameter to indicate it is a quantity expressed as per unit area.

BARPA-C/AUST-04/1hr, BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/1hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

rsdsdif

Surface diffused downwelling shortwave radiation (W m-2)

This parameter is the diffused shortwave radiation from the Sun, incident on the Earth's surface. It is a flux parameter to indicate it is a quantity expressed as per unit area. Different from the direct shortwave radiation, it consists of rays that arrive at the surface after scattering by clouds and particles in the atmosphere. The parameter has been corrected for the solar zenith angle.

BARPA-C/AUST-04/20min

rsdsdir

Surface Direct Downwelling Shortwave Radiation (W m-2)

This parameter is the direct shortwave radiation from the Sun, incident on the Earth's surface. It is a flux parameter to indicate it is a quantity expressed as per unit area. Different from the diffused shortwave radiation, it consists of rays that come directly from the Sun's position in the sky. The parameter has been corrected for the solar zenith angle and the effect of topography.

BARPA-C/AUST-04/1hr, BARPA-C/AUST-04/20min, BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/1hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

A commonly used quantity direct normal irradiance (DNI) can be derived by dividing this parameter by the cosine of the solar zenith angle.

rsdt

TOA Incident Shortwave Radiation (W m-2)

This parameter is the amount of solar radiation that reaches the top of the Earth's atmosphere. This radiation is primarily shortwave. It is a flux parameter to indicate it is a quantity expressed as per unit area.

BARPA-C/AUST-04/1hr, BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/1hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

rss

Net downward shortwave flux at surface (W m-2)

This parameter is the difference between the incoming and outgoing shortwave radiation at the Earth's surface. The incoming radiation includes direct sunlight and diffused sky radiation that reaches the surface, and the outgoing radiation is the portion of the incoming radiation that is reflected back into the atmosphere, mainly due to the surface's albedo. Its value is positive when the incoming radiation exceeds the outgoing. It is a flux parameter to indicate it is a quantity expressed as per unit area.

BARPA-C/AUST-04/20min

rsus

Surface Upwelling Shortwave Radiation (W m-2)

This parameter is the amount of shortwave solar radiation that is reflected back into the atmosphere from the Earth's surface, mainly due to the surface's albedo. It is a flux parameter to indicate it is a quantity expressed as per unit area.

BARPA-C/AUST-04/1hr, BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/1hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

rsuscs

Surface Upwelling Clear-Sky Shortwave Radiation (W m-2)

This parameter is the amount of shortwave solar radiation that is reflected back into the atmosphere from the Earth's surface under clear-sky conditions, mainly due to the surface's albedo. It is a flux parameter to indicate it is a quantity expressed as per unit area.

BARPA-C/AUST-04/1hr, BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/1hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

rsut

TOA Outgoing Shortwave Radiation (W m-2)

This parameter is the amount of shortwave solar radiation that is reflected back into space from the top of the Earth's atmosphere. It is a flux parameter to indicate it is a quantity expressed as per unit area.

BARPA-C/AUST-04/1hr, BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/1hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

rsutcs

TOA Outgoing Clear-Sky Shortwave Radiation (W m-2)

This parameter is the amount of shortwave solar radiation that is reflected back into space from the top of the Earth's atmosphere, under clear-sky conditions. It does not include radiation reflected by cloud. It is a flux parameter to indicate it is a quantity expressed as per unit area.

BARPA-C/AUST-04/1hr, BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/1hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

sund

Daily Duration of Sunshine (s)

This parameter is the length of time, in a day, that the direct solar irradiance exceeds a threshold value of 120 W m2. It indicates the level of cloudiness and sunniness of a location.

BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon

AUSWIND

AusWind Parameter (1)

AUSWIND is a diagnostic developed by Brown and Dowdy (2021a) as a proxy for severe convective wind (SCW) events in reanalyses and climate models. Brown and Dowdy (2021a) developed four logistic regression models relating the probability of an SCW to characteristics of the large-scale environment using data from Australia. AUSWIND is based on one of these models; specifically, the one trained on measured wind gusts using data from version 1 of the Bureaa of Meteorology Atmospheric Regional Reanalysis for Australia (BARRA). The logistic regression equation takes five convective parameters as input, namely effective bulk wind difference (EBWD), 1-3 km lapse rate (LR13), 0-3 km mean wind speed (U03mean), mixed-layer equilibrium level (MLEL), and 0-3 km minimum relative humidity (RH03min). The output (AUSWIND) represents the probability of an SCW event, specifically within the next hour, though the diagnostic can be applied to longer time periods (3 or 6 hours) if hourly data are not available. Brown and Dowdy (2021b) used AUSWIND alongside several other parameters to investigate the climatology and projected trends in SCW events across Australia.

BARPA-R/AUST-15/3hr

AUSWIND has previously been referred to as the Brown and Dowdy Statistical Diagnostic (BDSD; e.g., Brown and Dowdy 2021b).

BWD03

0 to 3 km AGL Bulk Wind Difference (m s-1)

Bulk wind difference (BWD) is defined as the vector difference between the winds at the top and bottom of a layer. It provides a measure of vertical wind shear, a key ingredient for organised convective storms such as squall lines and supercells. The magnitude of the 0-3 km BWD (BWD03) is a component of the fixed-layer SHERB (severe hazards in environments of reduced buoyancy) parameter, a diagnostic developed in the US for forecasting severe weather in high-shear, low-CAPE environments (Sherburn and Parker 2014). The direction of the 0-3 km BWD (BWD03dir) can be used in combination with its magnitude to compute the eastward and northward components of the vector. These can in turn be used in combination with the components of the 0-1 km BWD to compute the 1-3 km BWD or in combination with the components of the 0-6 km BWD to compute the 3-6 km BWD.

BARPA-R/AUST-15/3hr

The lowest model level is used in place of 0 km AGL. Directions represent the "from direction" and are measured clockwise from the north, such that values of 0, 90, 180, and 270 degrees represent vectors pointing from the north, east, south, and west, respectively.

BWD06

0 to 6 km AGL Bulk Wind Difference (m s-1)

Bulk wind difference (BWD) is defined as the vector difference between the winds at the top and bottom of a layer. It provides a measure of vertical wind shear, a key ingredient for organised convective storms such as squall lines and supercells. The magnitude of the 0-6 km BWD (BWD06) has been found to discriminate between supercells and ordinary thunderstorms (Rasmussen and Blanchard 1998; Thompson et al. 2003) and is thus a useful diagnostic for severe weather, such as large hail and tornadoes (e.g., Rasmussen 2003; Thompson et al. 2012; Taszarek et all. 2020). BWD06 is a component of the original fixed-layer supercell composite parameter (SCP) and significant tornado parameter (STP), diagnostics developed in the US for forecasting supercell thunderstorms and tornadoes, respectively (Thompson et al. 2003). It is also a component of the significant hail parameter (SHIP) and the derecho composite parameter (DCP), diagnostics developed in the US for forecasting large hail and cold pool-driven severe convective wind gusts, respectively (Storm Prediction Center 2024a,c). BWD06 can additionally be combined with mixed-layer or most-unstable CAPE to calculate WMAXSHEAR, a simple composite parameter that shows skill in discriminating between and severe and non-severe thunderstorms (e.g., Taszarek et al. 2020). The direction of the 0-6 km BWD (BWD06dir) can be used in combination with its magnitude to compute the eastward and northward components of the vector. These can in turn be used in combination with the components of the 0-3 km BWD to compute the 3-6 km BWD or in combination with the components of the 0-9 km BWD to compute the 6-9 km BWD.

BARPA-R/AUST-15/3hr

The lowest model level is used in place of 0 km AGL. Directions represent the "from direction" and are measured clockwise from the north, such that values of 0, 90, 180, and 270 degrees represent vectors pointing from the north, east, south, and west, respectively.

CAPE* (CAPE, CAPEmax)

Convective Available Potential Energy (J kg-1)

Convective available potential energy (CAPE) is defined as the vertical integral of positive buoyancy between the level of free convection (LFC) and the equilibrium level (EL). It provides a measure of conditional instability, a key ingredient for thunderstorm development. Higher values of CAPE have been shown to be more favourable for thunderstorms (e.g., Craven and Brooks 2004; Westermeyer et al. 2017) and severe weather, including large hail and tornadoes (e.g., Rasmussen and Blanchard 1998; Thompson et al. 2012; Taszarek et al. 2020). However, large CAPE does not guarantee that thunderstorms or severe weather will occur.

BARPA-C/AUST-04/1hr, BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/1hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon, BARPA-R/AUST-15/3hr, BARPA-R/AUST-15/day, BARPA-R/AUST-15/mon

The surface-based (SB) parcel is defined using the properties at the lowest model level. The parcel is assumed to ascend dry adiabatically to the lifting condensation level (LCL) and pseudoadiabatically thereafter. Ice processes, entrainment, and pressure perturbations are all neglected.

CIN* (CIN, CINmax)

Convective Inhibition (J kg-1)

Convective inhibition (CIN) is defined as minus the vertical integral of negative buoyancy between the surface and the equilibrium level (EL). It provides a measure of the negative energy that must be overcome in order for conditional instability to be released. Lower values of CIN have been shown to be more favourable for thunderstorms (e.g., Westermeyer et al. 2017) and tornadoes (e.g., Thompson et al. 2012), as well as for the persistence of supercells following the nocturnal transition (Gropp and Davenport 2018). However, a moderate amount of CIN (tens to a few hundred J/kg) can delay convection initiation, allowing CAPE to build up to levels more favourable for severe thunderstorms. Note that CIN is undefined (NaN) where CAPE = 0.

BARPA-C/AUST-04/1hr, BARPA-C/AUST-04/day, BARPA-C/AUST-04/mon, BARPA-R/AUS-15/1hr, BARPA-R/AUS-15/day, BARPA-R/AUS-15/mon, BARPA-R/AUST-15/3hr, BARPA-R/AUST-15/day, BARPA-R/AUST-15/mon

The surface-based (SB) parcel is defined using the properties at the lowest model level. The parcel is assumed to ascend dry adiabatically to the lifting condensation level (LCL) and pseudoadiabatically thereafter. Ice processes, entrainment, and pressure perturbations are all neglected.

DCAPE

Downdraft Convective Available Potential Energy (J kg-1)

Downdraft convective available potential energy (DCAPE) is defined as minus the vertical integral of negative buoyancy between the downdraft parcel level (DPL) and the surface. It provides a measure of the energy available to a saturated descending parcel of air, which can be converted to horizontal momentum when the parcel reaches the surface. Higher values of DCAPE have been found to be more favourable for cold pool-driven severe convective windstorms, such as derechos (e.g., Evans and Doswell 2001; Kuchera and Parker 2006; Cohen et al. 2007). DCAPE is a component of the derecho composite parameter (DCP), a diagnostic developed in the US for forecasting cold pool-driven severe convective windstorms (Storm Prediction Center, 2024a). Note that DCAPE is undefined (NaN) where the downdraft parcel is undefined.

BARPA-R/AUST-15/3hr

The downdraft parcel is defined using the properties at the level of minimum wet-bulb potential temperature between the most-unstable lifting condensation level (MULCL) and the mid-point between the MULCL and most-unstable equilibrium level (MUEL). Where the distance between the MULCL and MUEL is less than 2 km, the downdraft parcel is undefined. The parcel is assumed to descend pseudoadiabatically. Ice processes, entrainment, and pressure perturbations are all neglected.

DCP

Derecho Composite Parameter (1)

The derecho composite parameter (DCP) is a multi-ingredient composite index developed in the US for forecasting cold-pool-driven severe convective wind (SCW) events (Storm Prediction Center 2024a). It combines downdraft convective available potential energy (DCAPE), most-unstable convective available potential energy (MUCAPE), 0-6 km bulk wind difference (BWD06), and 0-6 km mean wind (U06mean). Brown and Dowdy (2021a) found that DCP was one of the more skilful diagnostics for SCW events in Australia, when applied to data from ERA5, though it was significantly outperformed by their own logistic regression-based diagnostic (AUSWIND). Brown and Dowdy (2021b) used DCP alongside other parameters (including AUSWIND) to investigate the climatology and projected trends in SCW events across Australia.

BARPA-R/AUST-15/3hr

FZL

Freezing Level Height AGL (m)

The freezing level (FZL) is defined as the height above ground level (AGL) at which the environmental temperature first drops below 0 degC. A higher FZL is indicative of a warmer environment, which may be more favourable for thunderstorms but less favourable for hail (particularly small hail) due to enhanced melting. FZL is a component of the improved instability-shear hail proxy for Australia developed by Raupach et al. (2023). Note that FZL is undefined (NaN) where the temperature at the lowest model level is below 0 degC.

BARPA-R/AUST-15/3hr

LR03

0 to 3 km AGL Lapse Rate (K m-1)

The 0-3 km lapse rate (LR03) is defined as the difference in temperature between the surface and 3 km above ground level (AGL) divided by the layer depth. Large values of LR03 may be favourable for severe convective winds as they will promote a more rapid decrease in buoyancy for descending saturated parcels. LR03 is a component of the enhanced stretching potential (ESP), a diagnostic developed in the US for forecasting tornadoes (Storm Prediction Center, 2024b). It can also be combined with the 0-1 km lapse rate (LR01) to compute the 1-3 km lapse rate, which is a component of the Australian severe convective wind parameter (AUSWIND) developed by Brown and Dowdy (2021a).

BARPA-R/AUST-15/3hr

The lowest model level is used in place of 0 km AGL.

LR75

700 to 500 hPa Lapse Rate (K m-1)

The 700-500 hPa lapse rate (LR75) is defined as the difference in temperature between 700 and 500 hPa divided by the layer depth. Large values of LR75 may be favourable for thunderstorms and severe weather as they will promote larger CAPE and stronger convective updrafts. They can also indicate the presence of an elevated mixed layer (EML) (e.g., Carlson et al. 1983). LR75 is a component of the significant hail parameter (SHIP), a diagnostic developed in the US for forecasting large hail (Storm Prediction Center, 2024c). It is also a component of the SHERB (severe hazards in environments of reduced buoyancy) parameter, a diagnostic developed in the US for forecasting severe weather in high-shear, low-CAPE environments (Sherburn and Parker 2014).

BARPA-R/AUST-15/3hr

Lapse rate is defined as the temperature at the bottom of the layer minus the temperature at the top of the layer, divided by the layer depth. Positive LR thus indicates decreasing temperatures with height across the layer.

MLCAPE

Convective Available Potential Energy for Mixed-Layer Parcel (J kg-1)

Convective available potential energy (CAPE) is defined as the vertical integral of positive buoyancy between the level of free convection (LFC) and the equilibrium level (EL). It provides a measure of conditional instability, a key ingredient for thunderstorm development. Higher values of CAPE have been shown to be more favourable for thunderstorms (e.g., Craven and Brooks 2004; Westermeyer et al. 2017) and severe weather, including large hail and tornadoes (e.g., Rasmussen and Blanchard 1998; Thompson et al. 2012; Taszarek et al. 2020). However, large CAPE does not guarantee that thunderstorms or severe weather will occur. MLCAPE is a component of the significant tornado parameter (STP), a diagnostic developed in the US for forecasting tornadoes (Thompson et al. 2003, 2007; Coffer et al. 2019). It is also used as a predictor in the tornado and severe wind classifiers for the ProbSevere nowcasting system (Cintineo et al. 2020).

BARPA-R/AUST-15/3hr

The mixed-layer (ML) parcel is defined using the lowest model level pressure and the average potential temperature and mixing ratio over the lowest 500 m. The parcel is assumed to ascend dry adiabatically to the lifting condensation level (LCL) and pseudoadiabatically thereafter. Ice processes, entrainment, and pressure perturbations are all neglected.

MLCAPE03

Convective Available Potential Energy in 0 to 3 km AGL Layer for Mixed-Layer Parcel (J kg-1)

0-3 km mixed-layer convective available potential energy (MLCAPE03) is defined as the vertical integral of positive buoyancy between the level of free convection (LFC) and 3 km above ground level (AGL). Large values of MLCAPE03 have been linked to an enhanced risk of tornadoes (e.g., Rasmussen 2003; Taszarek et al. 2020), including those not associated with supercell storms (Carusco and Davies 2005). MLCAPE03 is a component of the enhanced stretching potential (ESP), a diagnostic developed in the US for forecasting tornadoes (Storm Prediction Center, 2024b).

BARPA-R/AUST-15/3hr

The mixed-layer (ML) parcel is defined using the lowest model level pressure and the average potential temperature and mixing ratio over the lowest 500 m. The parcel is assumed to ascend dry adiabatically to the lifting condensation level (LCL) and pseudoadiabatically thereafter. Ice processes, entrainment, and pressure perturbations are all neglected.

MLCIN

Convective Inhibition for Mixed-Layer Parcel (J kg-1)

Convective inhibition (CIN) is defined as minus the vertical integral of negative buoyancy between the surface and the equilibrium level (EL). It provides a measure of the negative energy that must be overcome in order for conditional instability to be released. Lower values of CIN have been shown to be more favourable for thunderstorms (e.g., Westermeyer et al. 2017) and tornadoes (e.g., Thompson et al. 2012), as well as for the persistence of supercells following the nocturnal transition (Gropp and Davenport 2018). However, a moderate amount of CIN (tens to a few hundred J/kg) can delay convection initiation, allowing CAPE to build up to levels more favourable for severe thunderstorms. MLCIN is a component of the significant tornado parameter (STP), a diagnostic developed in the US for forecasting tornadoes (Thompson et al. 2003, 2007; Coffer et al. 2019). It is also used as a predictor in the tornado classifier for the ProbSevere nowcasting system (Cintineo et al. 2020). Note that MLCIN is undefined (NaN) where MLCAPE = 0.

BARPA-R/AUST-15/3hr

The mixed-layer (ML) parcel is defined using the lowest model level pressure and the average potential temperature and mixing ratio over the lowest 500 m. The parcel is assumed to ascend dry adiabatically to the lifting condensation level (LCL) and pseudoadiabatically thereafter. Ice processes, entrainment, and pressure perturbations are all neglected.

MLLCL

Lifting Condensation Level Height AGL for Mixed-Layer Parcel (m)

The lifting condensation level (LCL) is defined as the level at which an adiabatically lifted parcel becomes saturated. It can be used as a proxy for convective cloud base. A higher LCL is generally less favourable for tornadoes but more favourable for downdraft-driven severe windstorms such as downbursts and derechos. MLLCL is a component of the significant tornado parameter (STP), a diagnostic developed in the US for forecasting tornadoes (Thompson et al. 2003, 2007; Coffer et al. 2019). It is also used as a predictor in the Additive Regression Convective Hazard Model (AR-CHaMo) for very large hail (Battaglioli et al. 2023).

BARPA-R/AUST-15/3hr

The mixed-layer (ML) parcel is defined using the lowest model level pressure and the average potential temperature and mixing ratio over the lowest 500 m. The parcel is assumed to ascend dry adiabatically to the lifting condensation level (LCL) and pseudoadiabatically thereafter. Ice processes, entrainment, and pressure perturbations are all neglected.

MUCAPE* (MUCAPE, MUCAPEmax)

Convective Available Potential Energy for Most-Unstable Parcel (J kg-1)

Convective available potential energy (CAPE) is defined as the vertical integral of positive buoyancy between the level of free convection (LFC) and the equilibrium level (EL). It provides a measure of conditional instability, a key ingredient for thunderstorm development. Higher values of CAPE have been shown to be more favourable for thunderstorms (e.g., Craven and Brooks 2004; Westermeyer et al. 2017) and severe weather, including large hail and tornadoes (e.g., Rasmussen and Blanchard 1998; Thompson et al. 2012; Taszarek et al. 2020). However, large CAPE does not guarantee that thunderstorms or severe weather will occur. MUCAPE is a component of the supercell composite parameter (SCP), a diagnostic developed in the US for forecasting supercell thunderstorms (Thompson et al. 2003, 2007; Gropp and Davenport 2018). It is also used as a predictor in the severe wind classifier for the ProbSevere nowcasting system (Cintineo et al. 2020).

BARPA-C/AUST-04/1hr, BARPA-C/AUST-04/3hr, BARPA-R/AUST-15/3hr

The most-unstable (MU) parcel is defined by lifting parcels from every model level between the surface and 500 hPa or the -20 degC level (whichever is lower) and retaining the one with the largest CAPE. If all lifted parcels feature CAPE = 0, the MU parcel is defined using the properties at the lowest model level. The parcel is assumed to ascend dry adiabatically to the lifting condensation level (LCL) and pseudoadiabatically thereafter. Ice processes, entrainment, and pressure perturbations are all neglected.

MUCIN* (MUCIN, MUCINmax)

Convective Inhibition for Most-Unstable Parcel (J kg-1)

Convective inhibition (CIN) is defined as minus the vertical integral of negative buoyancy between the surface and the equilibrium level (EL). It provides a measure of the negative energy that must be overcome in order for conditional instability to be released. Lower values of CIN have been shown to be more favourable for thunderstorms (e.g., Westermeyer et al. 2017) and tornadoes (e.g., Thompson et al. 2012), as well as for the persistence of supercells following the nocturnal transition (Gropp and Davenport 2018). However, a moderate amount of CIN (tens to a few hundred J/kg) can delay convection initiation, allowing CAPE to build up to levels more favourable for severe thunderstorms. MUCIN is a component of the CIN-scaled supercell composite parameter (SCP), a diagnostic developed in the US for forecasting supercell thunderstorms (Gropp and Davenport 2018). Note that MUCIN is undefined (NaN) where MUCAPE = 0.

BARPA-C/AUST-04/1hr, BARPA-C/AUST-04/3hr, BARPA-R/AUST-15/3hr

The most-unstable (MU) parcel is defined by lifting parcels from every model level between the surface and 500 hPa or the -20 degC level (whichever is lower) and retaining the one with the largest CAPE. If all lifted parcels feature CAPE = 0, the MU parcel is defined using the properties at the lowest model level. The parcel is assumed to ascend dry adiabatically to the lifting condensation level (LCL) and pseudoadiabatically thereafter. Ice processes, entrainment, and pressure perturbations are all neglected.

MUEL

Equilibrium Level Height AGL for Most-Unstable Parcel (m)

The equilibrium level (EL) is defined as the level at which a saturated and positively buoyant parcel becomes negatively buoyant. It represents the top of the free convective layer (FCL). In profiles featuring multiple FCLs, the EL of the FCL with maximum CAPE is used. The EL can be used as a proxy for convective cloud top. All else being equal, a higher EL is associated with larger CAPE, suggesting conditions more favourable for thunderstorms and severe weather. MUEL is a component of the significant hail parameter (SHIP), a diagnostic developed in the US for forecasting large hail (Storm Prediction Center, 2024c). Note that MUEL is undefined (NaN) where MUCAPE = 0.

BARPA-R/AUST-15/3hr

The most-unstable (MU) parcel is defined by lifting parcels from every model level between the surface and 500 hPa or the -20 degC level (whichever is lower) and retaining the one with the largest CAPE. If all lifted parcels feature CAPE = 0, the MU parcel is defined using the properties at the lowest model level. The parcel is assumed to ascend dry adiabatically to the lifting condensation level (LCL) and pseudoadiabatically thereafter. Ice processes, entrainment, and pressure perturbations are all neglected.

SCP* (SCPl, SCPr)

Fixed-Layer Supercell Composite Parameter for Bunkers Left Mover (1)

The supercell composite parameter (SCP) is a multi-ingredient composite index developed in the US for forecasting supercell thunderstorms (Thompson et al. 2002; Thompson et al. 2004). Values of SCP > 1 are considered indicative of enviromments favourable for supercells. Here, a fixed-layer version of SCP is used, which combines most-unstable convective available potential energy (MUCAPE) and convective inhibition (MUCIN), 0-6 km bulk wind difference (BWD06), and 0-3 km storm-relative helicity (SRH03). The MUCIN term was found by Gropp and Davenport (2018) to improve discimination between persistent and decaying supercells during the nocturnal transition. Varients of SCP are computed using Bunkers left (SCPl) and Bunkers right (SCPr) storm motion in the calculation of SRH03.

BARPA-R/AUST-15/3hr

The storm motion vector for right-moving supercells is calculated using Eq. 1 from Bunkers et al. (2000). The storm motion vector for left-moving supercells is calculated using a corrected version of Eq. 2 from Bunkers et al. (2000). Following Bunkers et al. (2014), the advective component of storm motion is calculated as the pressure-weighted 0-8 km mean wind.

SHIP

Significant Hail Parameter (1)

The Significant Hail Parameter (SHIP) is a multi-ingredient composite index developed in the US for forecasting large hail (Storm Prediction Center, 2024c). It combines most-unstable convective available potential energy (MUCAPE) and parcel mixing ratio at the lifted parcel level (MULPLmixr), air temperature at 500 hPa (ta500), 700-500 hPa lapse rate (LR75), and 0-6 km bulk wind difference (BWD06). SHIP has been used by Bednarczyk and Sousounis (2018) and by Dowdy et al. (2020) to investigate the climatology of hail-favourable environments across Australia.

BARPA-R/AUST-15/3hr

The secondary scaling factors (based on MUCAPE, LR75, and FZL) applied in the Storm Prediction Center's definition of SHIP are not used here; however, they can readily be applied post-hoc using the relevant parameters.

STP* (STPl, STPr)

Fixed-Layer Significant Tornado Parameter for Bunkers Left Mover (1)

The significant tornado parameter (STP) is a multi-ingredient composite index developed in the US for forecasting significant (EF2 or greater) tornadoes, conditional on the occurrence of a supercell thunderstorm (Thompson et al. 2002; Thompson et al. 2004). Values of STP > 1 are considered indicative of environments favourable for significant tornadoes. Here, a fixed-layer version of STP is used, which combines mixed-layer convective available potential energy (MLCAPE), convective inhibition (MLCIN), and lifting condensation level height (MLLCL), 0-6 km bulk wind difference (BWD06), and 0-1 km storm-relative helicity (SRH01). Variants of SCP are computed using Bunkers left (SCPl) and Bunkers right (SCPr) storm motion in the calculation of SRH01.

BARPA-R/AUST-15/3hr

The storm motion vector for right-moving supercells is calculated using Eq. 1 from Bunkers et al. (2000). The storm motion vector for left-moving supercells is calculated using a corrected version of Eq. 2 from Bunkers et al. (2000). Following Bunkers et al. (2014), the advective component of storm motion is calculated as the pressure-weighted 0-8 km mean wind.