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 in height. In particular, the instrument payload of BELUGA comprises three modular instrument packages for high-resolution meteorological, wind vector and broadband radiation measurements. Collocated data acquisition allows for estimates of the driving parameters in the energy balance at various heights. 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 multilayer 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.

New particle formation and its effect on cloud condensation nuclei abundance in the summer Arctic: a case study in the Fram Strait and Barents Sea

“…If compared to a study from Antarctica (Jokinen et al, 2018) or laboratory studies by Dunne et al (2016) from the CERN CLOUD (Cosmics Leaving Outdoor Droplets) chamber, our calculated H 2 SO 4 concentration is 10 to 30 times lower than that from previous studies. On the other hand, the results of this study are in agreement with a study by Ehn et al (2007), who studied the relationship between particle hygroscopicity and sulfuric acid concentration in boreal forest. The authors reported that the concentration of H 2 SO 4 , corresponding to 15 and 20 nm particle HGFs of 1.34 and 1.46, was in a range of 10 7 molecules cm −3 .…”

Application of the shipborne remote sensing supersite OCEANET for profiling of Arctic aerosols and clouds during Polarstern cruise PS106

“…Added value of the OCEANET measurements can be obtained when they are accompanied by additional observations. During the two-week ice floe camp performed in the frame of PASCAL, a tethered balloon site was set up for turbulence and radiation observations (Egerer et al, 2019) and a network covering 15 pyranometers to determine the spatial variability of the solar radiation was installed (Barrientos Velasco et al, 2019). In the context of this study, the turbulence as determined from the three-dimensional wind vector measured with high temporal resolution of several tens of Hertz by an ultrasonic anemometer attached to the tether of the balloon was used.…”

“…If this criteria was matched within more than one wavenumber interval the mean of all ε i for one spectrum was calculated. In order to evaluate the EDR estimated by cloud radar measurements, it was compared to EDR derived from the tethered balloon (Egerer et al, 2019). The time periods used for deriving EDR from the tethered balloon was 15 minutes, during which it was located at a constant height above ground.…”

“…Though being a key requirement to study the Arctic energy budget, detailed observations of Arctic clouds still are rare. To study these clouds, different aircraft campaigns have been conducted in recent years in the Arctic (e.g., Curry et al, 2000;Jacob et al, 2010;McFarquhar et al, 2011;Wendisch et al, 2019). While airborne measurements yield an unique, accurate description of the observed cloud, they lack the ability to measure the entire tropospheric column at once.…”

“…These data sets serve, e.g., as basis for model evaluation (Illingworth et al, 2007;Neggers, 2019) and radiative transfer calculations (Barrientos Velasco et al, 2019;Ebell et al, 2019). Hence, additionally to the airborne campaigns, several shipborne campaigns equipped with remote sensing instrumentation have been conducted in the past years in the Arctic (e.g., Uttal et al, 2002;Tjernström et al, 2004;Tjernström et al, 2014;Granskog et al, 2018;Wendisch et al, 2019). Observations of space-borne cloud radar and lidar, as done aboard Cloudsat (Stephens et al, 2008) and CALIPSO (Winker et al, 2003) provide in addition a large-scale overview of the Arctic cloud coverage (Liu et al, 2012).…”