Ship-based measurements of ice nuclei concentrations over the Arctic, Atlantic, Pacific and Southern oceans

Abstract

Abstract. Ambient concentrations of ice-forming particles measured during ship expeditions are collected and summarised with the aim of determining the spatial distribution and variability in ice nuclei in oceanic regions. The presented data from literature and previously unpublished data from over 23 months of ship-based measurements stretch from the Arctic to the Southern Ocean and include a circumnavigation of Antarctica. In comparison to continental observations, ship-based measurements of ambient ice nuclei show 1 to 2 orders of magnitude lower mean concentrations. To quantify the geographical variability in oceanic areas, the concentration range of potential ice nuclei in different climate zones is analysed by meridionally dividing the expedition tracks into tropical, temperate and polar climate zones. We find that concentrations of ice nuclei in these meridional zones follow temperature spectra with similar slopes but vary in absolute concentration. Typically, the frequency with which specific concentrations of ice nuclei are observed at a certain temperature follows a log-normal distribution. A consequence of the log-normal distribution is that the mean concentration is higher than the most frequently measured concentration. Finally, the potential contribution of ship exhaust to the measured ice nuclei concentration on board research vessels is analysed as function of temperature. We find a sharp onset of the influence at approximately −36 ∘C but none at warmer temperatures that could bias ship-based measurements.

Opinion: Cloud-phase climate feedback and the importance of ice-nucleating particles

“…In general, the INP concentrations in air masses associated with land are higher than those with a strong marine influence (McCluskey et al, 2018b;Vergara-Temprado et al, 2017;DeMott et al, 2016;Welti et al, 2020). This terrestrialmarine divide is related to the sources in the two environments.…”

“…Further evidence for a strong terrestrial source of INPs in the Arctic was found by Irish et al (2019a), with a correlation between INP concentrations and the time that air spent over bare land during late summer. In addition to mineral dust, which tends to control the INP population only below about −15 • C (Murray et al, 2012), there is evidence that there are strong sources of terrestrial biogenic material active at much warmer temperatures across the Arctic (Tobo et al, 2019;Wex et al, 2019). Terrestrial biogenic material might be associated with sediments from rivers (Tobo et al, 2019) or vegetated areas (Conen et al, 2016;Schnell and Vali, 1976).…”

Heterogeneous ice nucleation ability of aerosol particles generated from Arctic sea surface microlayer and surface seawater samples at cirrus temperatures

“…A wealth of recent studies has substantiated early findings from the 1970s that sea spray aerosol (SSA) particles are able to act as ice-nucleating particles (INPs) in the immersion freezing mode for clouds in the mixed-phase temperature regime between 273 and 235 K (e.g. Bigg, 1973;Schnell and Vali, 1975;Knopf et al, 2011;Wilson et al, 2015;DeMott et al, 2016;Ladino et al, 2016;McCluskey et al, 2017;Creamean et al, 2019;Irish et al, 2019;Welti et al, 2020;Wilbourn et al, 2020;Wolf et al, 2020). As a comprehensive overview of previous investigations, we recommend the compilation in Table 1 by Ickes et al (2020).…”

“…Mason et al, 2015;Ladino et al, 2019;Wex et al, 2019), ship-and aircraft-based measurements (e.g. McCluskey et al, 2018a;Hartmann et al, 2020;Welti et al, 2020), as well as complex laboratory experiments where phytoplankton blooms were simulated in large seawater tanks and wave channels, generating SSA particles by plunging sheets of water or breaking waves (e.g. DeMott et al, 2016;McCluskey et al, 2017;McCluskey et al, 2018b).…”

Measurement report: Ice nucleating abilities of biomass burning, African dust, and sea spray aerosol particles over the Yucatán Peninsula

“…Bigg (1973) collected aerosol samples in Australia, Schnell and Vali (1975) in Huntington Beach (California, US), in the Caribbean off Nassau (Bahamas), and in Vancouver and Nova Scotia (Canada), Rosinski et al (1987) over the Pacific Ocean, and Rosinski et al (1988) in the Gulf of Mexico (GoM). More recently, the ice nucleating abilities of particles present in the Arctic sea surface microlayer (Wilson et al, 2015;Irish et al, 2017Irish et al, , 2019 and the Arctic ambient aerosol were evaluated (DeMott et al, 2016;Creamean et al, 2018;Wex et al, 2019). Similar studies were performed over the eastern Mediterranean by Gong et al (2019), over the Southern Ocean by McCluskey et al (2018) and Welti et al (2020), over the North Atlantic by Wilbourn et al (2020), and over the tropical Atlantic by DeMott et al (2016), Welti et al (2018), Ladino et al (2019), Ladino et al (2020), and Gong et al (2020a).…”