Topic 2b - Part 1: Air quality measurements - in situ instruments & validating satellite data

In situ measurements are ones that are obtained through direct contact with the respective subject.

In this video Dr Andreas Richter shows us an in situ instrument on the roof of Bremen University in Germany. This is the IUP-Bremen MAX-DOAS (Multi Axis Differential Optical Absorption Spectroscopy) instrument. This instrument is equipped with a smaller telescope housing which is mounted on a pan-and-tilt head that allows a direct pointing in any viewing direction.

The instrument works by light, that has been scattered in the atmosphere, entering the telescope housing through a quartz glass window, and this light is focused by a lens limiting the field of view onto an optical quartz fibre bundle, which is then looked at in the lab.

In situ instruments like this one can be used for the validation of satellite measurements. The MAX-DOAS instrument for example can be compared with measurements from satellite instruments such as GOME, GOME-2, SCIAMACHY, Sentinel-5p and OMI.

Featured Educator:

  • Dr Andreas Richter

Don’t forget you can download the video, transcript and take any quizzes available with the links on the right.

Optional Further Reading

Interactive Apps

Satellite tracking app - Topic 2b part 1

The satellites featured in this topic are as follows:

Sentinel-5p; Aura; ENVISAT; ERS-2; Metop-a; Metop-b; OCO-2

You can also use the drop-down menu in the app to view these satellites.


Telescope unit of the Bremen MAX-DOAS instrument

The MAX-DOAS is a remote sensing instrument collecting scattered sunlight in the UV and visible wavelength range, used in the MeSMarT project.