Global Satellite Images

The range of available satellite images has been expanded. In addition to the RGB channel, three IR channels with central wavelengths of 1.6 μm, 3.9 μm as well as 10.4 μm have been added to the API:

parameters: sat_ir_016:idx | sat_ir_039:idx | sat_ir_104:idx

Each channel can be used to identify different phenomena:

  • IR 1.6 μm:

    • Differentiation between ice and water clouds (higher absorption in ice than in water)

    • Easy recognition of snow (due to low reflectivity of ice and snow)

    • Water clouds can be distinguished from snow cover

  •  

  • IR 3.9 μm:

    • Provides images during daytime and nighttime

    • Urban heat islands can be detected at night

    • Recognition of low clouds and fog as well as thin cirrus clouds (day and night)

    • Recognition of sand, volcanic eruptions and wildfires

    • Besides the distinction of cloud phases, super-cooled clouds can be identified

    • Recognition of convective clouds

  •  

  • IR 10.4 μm:

    • Provides images during daytime and nighttime

    • Allows for interpretation of surface and cloud top temperatures

    • Enables continuous monitoring of air masses and the development of cyclones and anticyclones

sat_example

Comparison of RGB channel (left) and channel 3.9 μm (right). The advantage of using a different wavelength is the ability of getting nighttime images. Besides, convective clouds within the ITCZ are clearly visible.


 

Equivalent Potential Temperature (θe)

The important meteorological parameter θe is also available in the API now. It is a powerful concept for identifying different air masses and weather patterns such as frontal systems. The parameter can be queried for all common pressure levels and is continuously available at all heights. Units can be either in Celsius or Kelvin.

parameter: theta_e_<level>:<unit>

theta_e_example

Two cyclones with cold and warm front with clearly visible warm sector.

Documentation θe


 

Probability for Snowfall

Another new parameter is the probability for snowfall. This parameter checks all relevant meteorological conditions in order to decide if precipitation occurs in the form of snow. The result is provided in percent.

parameter: snow_fall:p

snowfall_example

Probability for snowfall on the Balkans during the passage of a cold front on April 14th in 2020.

Documentation Snowfall Probability


 

Cold Index

This new index tells how favorable given weather conditions are for catching a cold. The higher the index, the higher the risk.

parameter: cold_index:idx

cold_index

Cold index for Switzerland on March 7th, 2020.

Documentation Cold Index


 

Soil Frost

This parameter evaluates surface and ground temperatures and calculates the probability for soil frost.

parameter: soil_frost:p

soilfrost_example

Probability for soil frost on April 1st, 2020 (red colors indicate high probabilities).

Documentation Soil Frost


 

Apparent Temperature

The apparent temperature unites effects of relative humidity, wind speed and solar radiation and acts as a measure for the human thermal comfort.

parameter: t_apparent:C

tapparent_example

Air temperature and apparent temperature for St. Gallen (end of June/beginning of July 2019).

Documentation Apparent Temperature


 

Leisure Indices

The new leisure indices assess specific meteorological conditions for different outdoor/indoor activities. Activities that can be queried are: ballooning, bbq, beach, biking, climbing, fishing, gardening, gliding, hiking, hunting, sailing, skiing and tv.

parameter: leisure_<activity>:idx

Documentation Leisure Indices