Atmospheric Pressure and Density API Parameters

Pressure Adjusted to Sea Level | Mean Pressure Adjusted to Sea Level over the Last 10 Years | Surface Pressure | Surface Pressure Mean | Pressure at Higher Altitudes | Air Density | Geopotential Height | Interval Values of Geopotential Height | Layer Thickness

The computation of pressure parameters is based on data of NASA's SRTM digital elevation model, where it is available (between 60°N and 60°S). Model topography is used elsewhere.

Pressure Adjusted to Sea Level

Gives the pressure adjusted to sea level. To adjust the pressure to the mean sea level atmospheric conditions such as temperature are taken into account.
This parameter is also known as QFF.
msl_pressure:<unit>

Available units: hPa, Pa, psi

Examples

Note (especially for aviation):
It is possible to get from weather station data the pressure that is adjusted to mean sea level by applying the standard atmosphere of ICAO. This mean sea level pressure is also known as QNH.

msl_pressure_icao:<unit>

Available units: hPa, Pa

Examples

Mean Pressure Adjusted to Sea Level over the Last 10 Years

Gives the mean adjusted pressure (QFF) over the last 10 years on a certain date at a specific location.

msl_pressure_10y_mean:<unit>

Available units: hPa, psi

Examples:

Surface Pressure

Gives the surface pressure also known as QFE.
sfc_pressure:<unit>

Available units: hPa, Pa, psi

Examples

Surface Pressure Mean

Gives the surface pressure mean over the given interval.
sfc_pressure_mean_<interval>:<unit>

Available intervals: 1h - 24h (spacing: 1 h)

Available units: hPa, Pa, psi

Examples

Pressure at Higher Altitudes

The atmospheric pressure is available at any height level above ground up to 10 km.
pressure_<level>:<unit>

Available altitude levels: 1m - 20000m (continuously)

The level can be combined with the mean over a time interval.
pressure_mean_<level>_<interval>:<unit>

Available intervals: 1h - 24h (spacing: 1 h)

Available units: hPa, Pa, psi

Examples

Atmospheric Density

The density of air at any height level above ground up to 10 km.
air_density_<level>:<unit>

Available altitude levels: 2m - 20000m (continuously)

Available flight levels: FL10 - FL900 (continuously)

Available units: kgm3

air_density_mean_<level>_<time>:<unit>

Available intervals: 1h - 24h (spacing: 1 h)

Available units: kgm3

Examples

Geopotential Height

Gives the geopotential height in meters or decameters at the indicated level. The geopotential height differs from geometric height (elevation above sea level) and takes into account the variation of gravity with latitude and elevation.

geopotential_height_<level>:<unit>

Available levels (global): 1000hPa, 950hPa, 925hPa, 900hPa, 850hPa, 800hPa, 700hPa, 500hPa, 300hPa, 250hPa, 200hPa, 150hPa, 100hPa, 70hPa, 50hPa, 10hPa
Available flight levels: FL10 - FL900 (continuously)

Available units: m, dam

Examples

Interval Values of Geopotential Height

Gives the mean, maximum or minimum geopotential at the indicated flight level over the indicated duration.

geopotential_height_<measure>_<level>_<interval>:<unit>

Available flight levels: FL10 - FL900 (continuously)

Available measures: mean, min, max

Available intervals: 1h, 3h, 6h, 12h, 24h

Available units: m, dam

Examples

Layer Thickness

Layer thickness is a measure of how warm or cold a layer of the atmosphere is, usually a layer in the lowest 5 km (17,000 feet) of the troposphere; high values mean warm air, and low values mean cold air. Rain and snow are equally likely when the 500-1000 hPa thickness is about 5225 gpm (or 522 dam). Rain is rare when the 500-1000 hPa thickness is less than 5190 gpm. Snow is extremely rare when the 500-1000 hPa thickness is greater than 5395 gpm.

layer_thickness_<upper_level>_<lower_level>:<unit>
>Available level combinations:

layer_thickness_500hPa_1000hPa:<unit>

layer_thickness_500hPa_700hPa:<unit>

layer_thickness_700hPa_1000hPa:<unit>

layer_thickness_700hPa_850hPa:<unit>

layer_thickness_850hPa_1000hPa:<unit>

Available units: m, dam

Example