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Atmospheric constituents, such as aerosols and clouds, greatly affect theradiative properties of the atmosphere. Clouds play a substantial role in thisradiative balance. To better understand the contribution of cirrus clouds im-proved modelling and in-situ observations are needed.For further improving current climate-modelling parameters, accurate pa-rameterization of these clouds are required. From in-situ measurements, thesize distribution of cirrus ice particles, their concentration and shape param-eters can be determined. This can be achieved with the iBalloon-borne IceCloud particle Imager (B-ICI). Campaigns done with the B-ICI and resultingparameetrizations have contributed to more accurate characterization of cirrusclouds.The B-ICI is collecting and imaging ice particles with a pixel resolutionof 1,65 µm/pixel. With detailed image analysis at this accuracy particles >20µm can be distinguished, dimensions and concentration can be derived, andparticles can be sorted according to their shape. An improved version of B-ICIis currently being developed. This new version of the instrument is primarilyimproving image quality to enable easier and more automated image processing.Secondarily, changes in the design will reduce the weight of the instrumentand simplify the method for sampling of ice particles. A more light-weightinstrument will allow adding other sensors. In particular, an optical particlecounter to measure aerosol and small ice particles will be added to the B-ICI.This addition of an optical particle counter will result in more accurate sizedistributions in addition of providing complementary aerosol measurements. Inthis paper, we will highlight these changes and improvements in the B-ICI set-up.

The formation of ice particles in Earth's atmosphere strongly influences the dynamics and optical properties of clouds and their impacts on the climate system. Ice formation in clouds is often triggered heterogeneously by ice-nucleating particles (INPs) that represent a very low number of particles in the atmosphere. To date, many sources of INPs, such as mineral and soil dust, have been investigated and identified in the low and mid latitudes. Although less is known about the sources of ice nucleation at high latitudes, efforts have been made to identify the sources of INPs in the Arctic and boreal environments. In this study, we investigate the INP emission potential from high-latitude boreal forests in the mixed-phase cloud regime. We introduce the HyICE-2018 measurement campaign conducted in the boreal forest of Hyytiala, Finland, between February and June 2018. The campaign utilized the infrastructure of the Station for Measuring Ecosystem-Atmosphere Relations (SMEAR) II, with additional INP instruments, including the Portable Ice Nucleation Chamber I and II (PINC and PINCii), the SPectrometer for Ice Nuclei (SPIN), the Portable Ice Nucleation Experiment (PINE), the Ice Nucleation SpEctrometer of the Karlsruhe Institute of Technology (INSEKT) and the Microlitre Nucleation by Immersed Particle Instrument (mu L-NIPI), used to quantify the INP concentrations and sources in the boreal environment. In this contribution, we describe the measurement infrastructure and operating procedures during HyICE-2018, and we report results from specific time periods where INP instruments were run in parallel for inter-comparison purposes. Our results show that the suite of instruments deployed during HyICE-2018 reports consistent results and therefore lays the foundation for forthcoming results to be considered holistically. In addition, we compare measured INP concentrations to INP parameterizations, and we observe good agreement with the Tobo et al. (2013) parameterization developed from measurements conducted in a ponderosa pine forest ecosystem in Colorado, USA., Atmospheric Chemistry and Physics, 22 (8), ISSN:1680-7375, ISSN:1680-7367

The formation of ice particles in Earth’s atmosphere strongly influences the dynamics and optical properties of clouds and their impacts on the climate system. Ice formation in clouds is often triggered heterogeneously by ice nucleating particles (INPs) that represent a very low number of particles in the atmosphere. To date, many sources of INPs, such as mineral and soil dust, have been investigated and identified in the lower latitudes. Although less is known about the sources of ice nucleation at higher latitudes, efforts have been made to identify the sources of INPs in the Arctic and boreal environments. In this study, we investigate the INP emission potential from high latitude boreal forests. We introduce the HyICE-2018 measurement campaign conducted in the boreal forest of Hyytiälä, Finland between February and June 2018. The campaign utilized the infrastructure of the SMEAR II research station with additional instrumentation for measuring INPs to quantify the concentrations and sources of INPs in the boreal environment. In this contribution, we describe the measurement infrastructure and operating procedures during HyICE-2018 and we report results from specific time periods where INP instruments were run in parallel for inter-comparison purposes. Our results show that the suite of instruments deployed during HyICE-2018 reports consistent results and therefore lays the foundation for forthcoming results to be considered holistically. In addition, we compare the INP concentration we measured to INP parameterizations, and we show a very good agreement with the Tobo et al. (2013) parameterization developed from measurements conducted in a ponderosa pine forest ecosystem in Colorado, USA.