Calibrating the meteorological sensors of an air-mass following drifting balloon

The atmospheric temperature profile in Arctic winter plays a key role in the observed
Arctic amplification of global temperature changes. In the cold season, the Arctic atmo-
spheric temperature and moisture profiles are a product of advection and transformation
of air masses from lower latitudes [1, 2]. These poleward flowing air masses cool and dry
over several days, losing the majority of their initial heat and moisture content along
their trajectory. The occurrence of the resulting transition [3, 4] proves to be difficult to
understand using fixed-in-place (Eularian) observations [5, 6].

Altitude controlled drifting (CMET) balloons provide vertical profiles of the lower bound-
ary layer in an air-mass following (Lagrangian) perspective [7], deemed necessary for the
understanding of arctic air mass transformations [4].

While these balloons measure the same properties as commercial grade radiosondes,
their sensors have been found to be prone to radiative bias, lag and hysteresis effects dur-
ing previous deployments [8]. Accurate measurements within the arctic boundary layer
therefore require to distinguish between the sensor related errors, small-scale atmospheric
variability between adjacent ascending/descending legs and the observed processes.

Within this study, we followed established procedures used for calibrating and processing
radiosondes observations using a ground based standard humidity chamber, temperature
measurement and sensor manufacturer information.

We developed a pre-flight calibration routine combined with a processing tool for the
balloons’ raw data, correcting for the individual sensor characteristics, the balloons flight
dynamics and environmental factors. An evaluation of the radiative bias on temperature
measurements in a ground test chamber is planned later this year.

In summary, this will provide a comprehensive understanding of the total measurement
uncertainties of each sensor validated against a common reference standard for flight data
processing. Furthermore, our work aims at serving as a best-practice guideline for all
present and future users deploying the CMET system.

 

 

1. Wexler. Cooling in the lower atmosphere and the structure of polar continental
air. (1936)

2. Curry. On the Formation of Continental Polar Air. (1983)

3. Stramler et al. Synoptically Driven Arctic Winter
States. (2011)

4. Pithan et al. Role of air-mass transformations in exchange between the Arctic
and mid-latitudes. (2018)

5. Lonardi et al. Tethered balloon-borne observations of thermal-infrared irradiance
and cooling rate profiles in the Arctic atmospheric boundary layer. (2024)

6. Becker et al. In situ sounding of radiative flux profiles through the Arctic lower
troposphere. (2020)

7. Voss et al. Continuous In-Situ Soundings in the Arctic Boundary Layer: A
New Atmospheric Measurement Technique Using Controlled Meteorological Bal-
loons. (2012)

8. Roberts et al. Controlled meteorological (CMET) free balloon profiling of the
Arctic atmospheric boundary layer around Spitsbergen compared to ERA-Interim
and Arctic System Reanalyses. (2016)