MATS Science

MATS Science

Our atmosphere is full of waves. Similar to waves in our oceans, these waves can be generated by different mechanisms, propagate over long distances, break into turbulence, and strongly control local conditions. Waves in the atmosphere exist on many scales from local perturbation to global patterns. Recent research has revealed that waves can link together different parts of our climate system over long distances. An important goal of the MATS satellite mission is to investigate waves in the atmosphere. MATS focuses in particular on atmospheric altitudes between 50 and 100 km, the so called mesosphere.

In many ways, the mesosphere can be regarded as a transition region between the "usual atmosphere" around us and the "space" that takes over at higher altitudes. Here waves originating from the lower atmosphere can grow to large amplitudes and strongly affect everything from global wind patterns to local temperatures. In order to understand the atmosphere as a whole, we need to learn more about this transition region and its coupling to atmospheric conditions below and above.

The acronym MATS stands for "Mesospheric Airglow/Aerosol Tomography and Spectroscopy". What is behind this name? From its orbit about 600 km above the Earth's surface, MATS uses optical measurement techniques to study the mesosphere. It does so by making use of optical phenomena that are specific for the mesosphere. One such phenomenon is light emitted from oxygen molecules, a process called airglow. Another phenomenon is light scattered by aerosol particles in the form of "noctilucent clouds", the highest clouds in our atmosphere that can exist at altitudes around 80 km.

In order to gain information about atmospheric structures and wave patterns from these phenomena, MATS applies tomography: by observing at the mesosphere from many different directions it is possible to reconstruct a three-dimensional picture. Even more information can be obtained by combining tomography with spectroscopy: by analyzing the detected light at different wavelengths (colors) it becomes possible to draw conclusions e.g. about atmospheric temperatures, composition or cloud properties. By collecting data from the mesosphere for a period of two years, MATS will thus allow us to address a wide range of scientific questions about this remote part of the atmosphere.

A summary of the expected performance figures of MATS is given in following table

Quantity

Airglow

Temperature

NLC brightness

NLC Ångström

parameter

Temporal coverage

All seasons

All seasons

Summer

Summer

Geographical coverage

Global

Global

Polewards of 45

Polewards of 45

Altitudes (km)

75-100

75-100

80-85

80-85

Precision (typical)

1-5 %

2-20 K

2-5 %

0.25

Resolution (km, better than)

60x20x1

60x20x1

60x10x0.5

60x10x0.5