Measurements

The FAAM aircraft is equipped to measure a wide range of atmospheric variables, using instrumentation maintained by FAAM and its external collaborators and users. Some instrumentation is always fitted (barring serviceability issues), and some is user-selectable, depending on the project or application. Unless there are exceptional circumstances, data from all science instruments is made openly available at the Centre for Environmental Data Analysis (see Working with Processed Data).

Measurements made on every flight

Staff at the FAAM Airborne Laboratory maintain and operate a suite of instruments on the aircraft that cover the essential measurements that most of our users require as standard. These measurements are sometimes referred to as ‘core’ measurements (note that the words ‘core’ and ‘non-core’ are historical terms with diverse interpretations that can be somewhat confusing). As of May 2025, these measurements are as follows:

  • Aircraft position, orientation and velocity

  • High precision time

  • Pressure

  • Temperature

  • Water vapour concentration

  • Air motion

  • Electrical field measurements

  • Aerosol scattering

  • Bulk ice and liquid water content

  • Brightness temperature of the Earth’s surface or cloud tops

It is also possible to collect filter samples on any flight. The equipment to facilitate this is maintained by FAAM but usually operated by a FAAM-trained member of staff from the external organisation requiring the filter sample. FAAM does not provide any facilities for the preparation or analysis of filter samples, but can advise on previous use cases.

User-selectable measurements

Even though we can carry up to 4 tonnes of science equipment, there isn’t space to fit all of the instruments that could potentially be used at the same time. Some instruments or their inlets add weight and drag to the aircraft, increasing fuel consumption and reducing range, so these are only fitted when required for science.

User-selectable measurements provided by staff at FAAM are as follows (May 2025):

  • Carbon dioxide concentration

  • Methane concentration

  • Ozone concentration

  • Sulphur dioxide concentration

  • Nitrogen oxide, nitrogen dioxide and nitrous acid concentrations

  • Cloud condensation nuclei number concentration

  • Aerosol absorption

  • Aerosol concentration (various size ranges)

  • Cloud particle concentration and size

  • Cloud particle state and shape

  • Broadband radiative flux (visible and infrared) from above and below

  • Airframe static charge

FAAM staff are also able to launch dropsondes, which measure atmospheric profiles of pressure, temperature, relative humidity and wind beneath the aircraft.

User-selectable measurements made using instruments maintained and operated externally to FAAM are as follows (May 2025):

  • Aerosol LiDAR profiles

  • Non-refractory aerosol composition

  • Methane and nitrous oxide concentration

  • Ethane/13CH4 isotope concentration

  • Additional measurements of cloud particle concentration, size, state and shape

  • Speciated reactive nitrogen compounds

  • Formaldehyde

  • Actinic flux photolysis rates

  • Black carbon in individual aerosol particles

  • Particle size distribution, depolarisation

In addition to the above, there is also equipment that can be fitted that can enable the collection of gas samples for subsequent laboratory analysis. As with filters, FAAM does not provide any facilities for the analysis of gas samples, but can advise on previous use cases.

Potential future measurement capabilities include:

  • Volatile organic compound concentration

  • Ice nucleating particle concentration

  • Bioaerosol particle size distribution, imagery and emission spectra

  • Expanded range of trace gas concentrations

  • Peroxide concentrations

  • OH, HO2 ,RO2 radicals and OH reactivity

  • Sulfur dioxide, nitric oxide, nitrogen dioxide, and ozone concentrations

  • 3D wind profiles

  • Refractory aerosol composition and size

  • Concentrations of methane, ethane and C-13 isotopologues of methane

  • Improvements in the measurement of stereo particle size distribution; concentration; shape, aspect ratio, volume, and mass of cloud and precipitation particles

  • Aerosol backscatter above and below the aircraft

  • Holographic cloud particle imaging

  • Mid-to-far-infrared radiometry

Detailed information about measurements

Making measurements on an airborne platform can be challenging, and there are many factors to consider in interpreting data collected in this way. For example, it is important to consider instrument response rates, frequency of measurement, factors influencing measurement uncertainty, calibration procedures and traceability. Some instruments do not perform well under all conditions (e.g. some do not work in cloud, others only work when the aircraft is flying straight and level), and some instruments require in-flight calibration that can lead to loss of science data during these periods of calibration.

We have a wealth of information available to users, and this is best accessed via our in-house science team. Each flying project is assigned a FAAM-Science Link, a scientific member of staff at the facility who acts as a conduit for information between scientific users and the specialists responsible for FAAM’s instruments and data. The FAAM-Science Link will be able to answer many of your questions and point you towards relevant resources, as well as put you in touch with colleagues with more detailed knowledge if required.

Specifying your measurement requirements

See also Specifying Your Requirements.

When completing the FAAM Application Form you will be asked to identify which instruments you would like to be made available your project, and the degree of importance for your science. We understand that it can be difficult to know which instruments to select, and an in-depth knowledge of the various instruments is not required. FAAM staff, such as the Science Partnerships Lead and the FAAM-Science Link, are available to support you with this throughout your project lifecycle.

Many of the instruments that can be used on the FAAM aircraft require some discussion in advance with a relevant scientist. Details of who to contact are given in the instrument tab on the FAAM Application Form. Where the use of an instrument requires significant consumables, for example dropsondes and SATCOM data transfer, these additional costs are recovered directly from the project. Available instruments may change depending on user requirements and serviceability.