The Arctic marine climate system is changing rapidly, which is seen in the warming of the ocean and atmosphere, decline of sea ice cover, increase in river discharge, acidification of the ocean, and changes in marine ecosystems. Socio-economic activities in the coastal and marine Arctic are simultaneously changing. PEEX ("Pan-Eurasian Experiment”) is a research infrastructure program focused on climate and environmental changes in the Northern Eurasian arctic and boreal regions. Implementation of PEEX requires development of an Integrated Arctic Observing System, which is the overall goal of the INTAROS project. In this publication the need for a marine component of the Pan-Eurasian Experiment (MA-PEEX) is elaborated. 

- There is a need for more in situ observations on the marine atmosphere, sea ice, and ocean, but increasing the amount of such observations is a pronounced technological and logistical challenge, Stein Sandven at the Nansen Center says. He refers to has a new publication (Towards an advanced observation system for the marine Arctic in the framework of the Pan-Eurasian Experiment (PEEX)) in Atmospheric Chemistry and Physics which he has been one of authors to. Dmitry Pozdnyakov at Nansen International Environmental and Remote Sensing Centre in St. Petersburg, Russia, has also contributed to this publication.

The publication brings to attention that the SMEAR (Station for Measuring Ecosystem–Atmosphere Relations) concept can be applied in coastal and archipelago stations, but in the Arctic Ocean it will probably be more cost-effective to further develop a strongly distributed marine observation network based on autonomous buoys, moorings, autonomous underwater vehicles (AUVs), and unmanned aerial vehicles (UAVs). These have to be supported by research vessel and aircraft campaigns, as well as various coastal observations, including community-based ones. Major manned drifting stations may occasionally be comparable to terrestrial SMEAR flagship stations. To best utilize the observations, atmosphere–ocean reanalyses need to be further developed. To well integrate MA-PEEX with the existing terrestrial–atmospheric PEEX, focus is needed on the river discharge and associated fluxes, coastal processes, and atmospheric transports in and out of the marine Arctic. More observations and research are also needed on the specific socio-economic challenges and opportunities in the marine and coastal Arctic, and on their interaction with changes in the climate and environmental system. MA-PEEX will promote international collaboration; sustainable marine meteorological, sea ice, and oceanographic observations; advanced data management; and multidisciplinary research on the marine Arctic and its interaction with the Eurasian continent.

Figure 1: Differences in winter (DJF, a) and summer (JJA, b) 2 m air temperature (in ∘C) between the periods 2000–2015 and 1979–1999 according to ERA-Interim reanalysis. Figure drawn applying Climate Reanalyzer.

In this publication the authors first introduce some of the most important multidisciplinary observation systems in the marine Arctic. Then they describe the key processes in the atmosphere, sea ice, and ocean, as well as the observations available to understand and quantify them.

- The knowledge on physical, biogeochemical, and ecosystem processes in the Arctic Ocean and the overlying atmosphere is limited. Improvement of the observing system is, however, a pronounced technological and logistical challenge, Sandven says. 

In the design of MA-PEEX, the SMEAR concept, successfully applied in PEEX (Lappalainen et al., 2018), can be applied in coastal and archipelago stations, such as Tiksi, Cape Baranova, Ny-Ålesund, Barentsburg, and Villum Station Nord. A key question in the design of the observation system for the offshore regions is whether instead of the SMEAR concept it will be more cost-effective to further develop a strongly distributed marine observation network. The trend in marine observations, both globally and in the Arctic, has been towards increasing application of autonomous buoys, moorings, autonomous underwater vehicles (AUVs), and unmanned aerial vehicles (UAVs), and the relative importance of centralized observations in research vessels and ice stations has simultaneously decreased. In the Arctic these trends have been enhanced by the sea ice decline.

- Here we propose how to proceed and what actions are concretely needed to develop MA-PEEX. Particularly important is that MA-PEEX will be well integrated with the existing atmospheric, terrestrial, and socio-economic components of PEEX. MA-PEEX will promote international collaboration; sustainable marine meteorological, cryospheric, and oceanographic observations; advanced data management; and multidisciplinary research on the marine Arctic and its interaction with the Eurasian continent, Sandven explains. 

More observations and research are also needed on the specific socio-economic challenges and opportunities in the marine and coastal Arctic, and on their interaction with changes in the climate and environmental system. MA-PEEX will promote international collaboration; sustainable marine meteorological, sea ice, and oceanographic observations; advanced data management; and multidisciplinary research on the marine Arctic and its interaction with the Eurasian continent.

- MA-PEEX should be designed in collaboration with other programmes addressing the present and future observation networks in the Arctic, including the Sustaining Arctic Observation Networks (SAON) and the Arctic Monitoring and Assessment Programme (AMAP) established by the Arctic Council, the European Commission project Integrated Arctic Observation System (INTAROS), and several other programmes and networks, Sandven says.

Figure 3: Trajectories of Russian “North Pole” drifting stations in the 21st century.

Citation: Vihma, T., Uotila, P., Sandven, S., Pozdnyakov, D., Makshtas, A., Pelyasov, A., Pirazzini, R., Danielsen, F., Chalov, S., Lappalainen, H. K., Ivanov, V., Frolov, I., Albin, A., Cheng, B., Dobrolyubov, S., Arkhipkin, V., Myslenkov, S., Petäjä, T., and Kulmala, M.: Towards an advanced observation system for the marine Arctic in the framework of the Pan-Eurasian Experiment (PEEX), Atmos. Chem. Phys., 19, 1941-1970, https://doi.org/10.5194/acp-19-1941-2019, 2019.