Tropospheric water vapour observations by ground-based lidar

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SESS Report 2021 The State of Environmental Science in Svalbard - an annual report

Executive Summary The State of Environmental Science in Svalbard (SESS) report 2021 together with its predecessors contributes to the documentation of the state of the Arctic environment in and around Svalbard, and highlights research conducted within the Svalbard Integrated Arctic Earth Observing System (SIOS). Climate change is a global problem, but many of its impacts are being felt most strongly in the Arctic. Given its remote but accessible location, Svalbard constitutes an ideal place to study the Arctic environment in general, including, more specifically, the causes and consequences of climate change. The Arctic Climate Change Update (2021) emphasised the severity of global climate change for ecosystems across the Arctic. They are undergoing radical changes regarding their structure and functioning, affecting flora, fauna and livelihoods of Arctic communities. Oceanic ecosystems and food webs are directly and indirectly altered by the warming and freshening of the Arctic Ocean. A prolonged open water period and the expansion of open water areas caused by declining sea ice affect under-ice productivity and diversity. These changes have cascading effects through ecosystems and impact the distribution, abundance and seasonality of a variety of marine species. Svalbard is located at one of the key oceanic gateways to the Arctic. This land–ice–ocean transition zone is a system particularly vulnerable to environmental changes. Svalbard’s environment is influenced by maritime processes; thus extensive observation of the ocean system is nowadays necessary. The chapter on the iMOP project reports seawater temperature and salinity variability over the last decades and indicates changes of Svalbard fjord seawater properties. The chapter highlights the role of a collaborative and supportive network of observatory operators and encourages joint planning and maintenance of future marine observatories. Arctic vegetation plays a key role in land–atmosphere interactions. Alterations can lead to ecosystem–climate feedbacks and exacerbate climate change. Extreme precipitation events are already becoming more frequent. Together with an increasing rain-to-snow ratio they impact the structure and functioning of terrestrial ecosystems. Dynamics in Arctic tundra ecosystems are expected to undergo fundamental changes with increasing temperatures as predicted by climate models. To detect, document, understand and predict those changes, COAT Svalbard provides a long-term and real-time operational observation system through ecosystem-based terrestrial monitoring. The observation system consists of six modules comprising food web pathways as well as one climate-monitoring module and focuses on two contrasting regions in Svalbard to allow for intercomparison. To date, the project has done an initial assessment of tundra ecosystems in Norway and will now begin with the long-term ecosystembased monitoring. For remote regions such as the Svalbard archipelago, terrestrial photography is a crucial addition to satellite imagery, because land-based cameras offer high temporal resolution and insensitivity towards varying weather conditions. PASSES provides an overview of cameras operating in Svalbard managed by research institutions and private companies. The survey revealed difficulties and knowledge gaps preventing the full potential of the terrestrial photography network in Svalbard from being used. Therefore, PASSES recommends the creation of a Svalbard camera system network. The effects of climate change contributed to a specific anomaly of the springtime Arctic atmosphere, namely a pronounced depletion of stratospheric ozone during March and April 2020, which can be called an Arctic ozone hole. In Svalbard, the amount of ozone loss was recorded by ground-based dedicated spectroscopic instruments measuring the total ozone column as well as the UV irradiance (EXAODEP-2020, an update of UV Ozone). The latter is important for effects on the biota. Corresponding erythemal daily doses for spring 2020 show a doubling compared to previous years with less or no ozone depletion. While the correspondence between ozone loss and increase in UV doses follows a well-known relationship, the possible later consequences of the observed springtime increase of UV doses on Svalbard’s environment need to be further studied. A particular method to observe the Svalbard environment, which has seen a very strong increase in usage during recent years, is the application of unmanned airborne or marine vehicles. The update on recent publications using these devices (UAV Svalbard) reveals that especially conventional remotely operated aerial vehicles (drones) with camera equipment are now widely used. It is recommended to SIOS to foster interdisciplinary communication among the multitude of drone users to establish exchange of information and data. New EU regulations for drone operations are being put in place from 2022 onwards also in Svalbard. Climate services are receiving more and more attention from Arctic countries, because they translate data into relevant and timely information, thereby supporting governments, societies and industries in planning and decision-making processes. SIOS contributes to climate services by providing research infrastructure with an overarching goal to develop and maintain a regional observational system for long-term measurements in and around Svalbard. The SIOS Core Data (SCD) consists of a list of essential Earth System Science variables relevant to determine environmental change in the Arctic. SCD is developed to improve the relevance and availability of scientific information addressing ESS topics for decision-making. SIOS Core Data providers have committed to maintain the observations for at least five years, to make the data publicly available, and to follow advanced principles of scientific data management and stewardship. Arctic climate change is posing risks to the safety, health and well-being of Arctic communities and ecosystems. Still, there remain gaps in our understanding of physical processes and societal implications. The authors of the SESS chapters have highlighted some unanswered questions and suggested concrete actions that should be taken to address them. The editors would like to thank the authors for their valuable contributions to the SESS Report 2021. These chapters illustrate how SIOS projects contribute to ensure the future vitality and resilience of Arctic peoples, communities and ecosystems

Near-range receiver unit of next generation PollyXT used with Koldeway aerosol Raman lidar in Arctic

The Near-range Aerosol Raman lidar (NARLa) receiver unit, that was designed to enhance the detection range of the NeXT generation PollyXT Aerosol-Depolarization-Raman (ADR) lidar of the University of Warsaw, was employed next the Koldeway Aerosol Raman Lidar (KARL) at the AWI-IPEV German-French station in Arctic during Spring 2015. Here we introduce shortly design of both lidars, the scheme of their installation next to each other, and preliminary results of observations aiming at arctic haze investigation by the lidars and the iCAP a set of particle counter and aethalometer installed under a tethered balloon

2014年冬季北極成層圏でのエアロゾル中不揮発性成分の観測

第6回極域科学シンポジウム[OM] 極域気水圏11月16日（月）　国立極地研究所１階交流アトリウ

Investigation of aerosol optical properties in the European Arctic using Lidar remote sensing technique

Aerosol strongly affect the radiation balance, especially in the Arctic where climate change is significantly faster compared to lower latitudes. The interaction between aerosol and radiation can be either direct (scattering and absorption) or indirect (aerosol serving as cloud condensation nuclei and ice nucleating particles). Aerosol optical properties can be provided by Lidar (Light Detection and Ranging) systems with high spatial and temporal resolution. In this study, we utilize data from a ground-based Lidar system located in Ny-Ålesund, Spitsbergen and an air-borne system installed onboard the research aircraft Polar5. Our focus is on a rare event of elevated aerosol layers, which persistently appeared over two different parts of the European Arctic during PAMARCMiP (Polar Air-borne Measurements and Arctic Regional Climate Model Simulation Project) campaign in spring 2018. Results show that the detected layers exhibit similar optical properties, namely aerosol backscatter coefficient, which is indicative of aerosol abundance and aerosol depolarization ratio, which is an indicator of the aerosol shape. The main hypothesis is that although the existence of those layers is rare, they impact on the radiation budget of the Arctic. In the next steps of our research, we will investigate the occurrence of similar aerosol layers in the springtime of previous years using long-term measurements from the Lidar system located in Ny-Ålesund. Our goal is to assess the effect of different aerosol layers on the surface radiation budget and gain a better understanding of their role in the amplified Arctic climate change, utilizing radiation measurements from the Ny-Ålesund BSRN (Baseline Surface Radiation Network) station

Optical Properties of Arctic Aerosol during PAMARCMiP 2018

Aerosol strongly affect the radiation balance, especially in the Arctic where climate change is significantly faster compared to lower latitudes, a phenomenon known as Arctic Amplification. The interaction between aerosol and radiation can be either direct (scattering and absorption) or indirect (aerosol serving as cloud condensation nuclei and ice nucleating particles).Aerosol concentration in the accumulation mode exhibits an annual maximum in the Arctic in springtime, forming the Arctic Haze. In this work, elevated layers from the European Arctic are analyzed in terms of their optical and hygroscopic properties

Arctic experiment for ICESat/GLAS ground validation with a Micro-Pulse Lidar at Ny-Alesund, Svalbard

A Micro-Pulse Lidar (MPL) has been operated in Ny-Alesund, Svalbard (78°55\u27N, 11°56\u27E, 0.010 km msl) to collect zenith scattering profiles of aerosols and clouds since 1998. The Ice, Cloud, and land Elevation Satellite (ICESat) was launched by NASA in January 2003 with a single payload instrument, the Geoscience Laser Altimeter System (GLAS), designed for active remote sensing of the atmosphere as well as ice sheet height change in the cryosphere. Overpass experiments for ground validation of the ICESat/GLAS atmospheric measurements were performed in 2003 and 2004. Two case-studies comparing lidar measurements from space-borne GLAS and ground-based MPL in the Arctic are described here for a geometrically thick but optically thin cloud and a geometrically thin but optically thick cloud. The result validates the basic procedure for cloud signal processing and attenuation correction of the GLAS data