The new BELUGA setup for collocated turbulence and radiation measurements using a tethered balloon: First applications in the cloudy Arctic boundary layer

Abstract

Abstract. The new BELUGA (Balloon-bornE moduLar Utility for profilinG the lower Atmosphere) tethered balloon system is introduced. It combines a set of instruments to measure turbulent and radiative parameters and energy fluxes. BELUGA enables collocated measurements either at a constant altitude or as vertical profiles up to 1.5 km height. In particular, the instrument payload of BELUGA comprises three modular instrument packages for high resolution meteorological, wind vector and broadband radiation measurements. The collocated data acquisition allows to estimate the driving parameters of the energy balance in various altitudes. Heating rates and net irradiances can be related to turbulent fluxes and local turbulence parameters such as dissipation rates. In this paper the technical setup, the instrument performance, and the measurement strategy of BELUGA are explained. Furthermore, the high vertical resolution due to the slow ascent speed is highlighted as a major advantage of tethered balloon-borne observations. Three illustrative case studies of the first application of BELUGA in the Arctic atmospheric boundary layer are presented. As a first example, measurements of a single layer stratocumulus are discussed. They show a pronounced cloud top radiative cooling of up to 6 K h−1. To put this into context, a second case elaborates respective measurements with BELUGA in a cloudless situation. In a third example, a multi layer stratocumulus was probed, revealing reduced turbulence and negligible cloud top radiative cooling for the lower cloud layer. In all three cases the net radiative fluxes are much higher than turbulent fluxes. Altogether, BELUGA has proven its robust performance in cloudy conditions of the Arctic atmospheric boundary layer.

Evaluation of ARM Tethered Balloon System instrumentation for supercooled liquid water and distributed temperature sensing in mixed-phase Arctic clouds

“…Tethered balloon systems have been used to collect tropospheric atmospheric measurements for over 40 years, including profiles of biogenic compounds, chemical species, turbulence, radiation, and meteorological parameters (e.g., Morris et al, 1975;Owens et al, 1982;Greenberg et al, 1998;Knapp et al, 1998;Egerer et al, 2019). Morris et al (1975) developed a portable tethered balloon system that essentially behaved as a tethered radiosonde that was able to be operated by one person at altitudes up to 750 m above ground level (AGL) in wind speeds as high as 10 m/s.…”

“…Knapp et al (1998) combined tethered balloon system and kite measurements to study the anticorrelation between ozone and water vapor mixing ratios. Most recently, in Egerer et al (2019 operated sets of 25 instruments to measure turbulent, energy, and radiative fluxes to altitudes of 1.5 km AGL within Arctic clouds.…”