Overview: Recent advances in the understanding of the northern Eurasian environments and of the urban air quality in China – a Pan-Eurasian Experiment (PEEX) programme perspective

Abstract

Abstract. The Pan-Eurasian Experiment (PEEX) Science Plan, released in 2015, addressed a need for a holistic system understanding and outlined the most urgent research needs for the rapidly changing Arctic-boreal region. Air quality in China, together with the long-range transport of atmospheric pollutants, was also indicated as one of the most crucial topics of the research agenda. These two geographical regions, the northern Eurasian Arctic-boreal region and China, especially the megacities in China, were identified as a “PEEX region”. It is also important to recognize that the PEEX geographical region is an area where science-based policy actions would have significant impacts on the global climate. This paper summarizes results obtained during the last 5 years in the northern Eurasian region, together with recent observations of the air quality in the urban environments in China, in the context of the PEEX programme. The main regions of interest are the Russian Arctic, northern Eurasian boreal forests (Siberia) and peatlands, and the megacities in China. We frame our analysis against research themes introduced in the PEEX Science Plan in 2015. We summarize recent progress towards an enhanced holistic understanding of the land–atmosphere–ocean systems feedbacks. We conclude that although the scientific knowledge in these regions has increased, the new results are in many cases insufficient, and there are still gaps in our understanding of large-scale climate–Earth surface interactions and feedbacks. This arises from limitations in research infrastructures, especially the lack of coordinated, continuous and comprehensive in situ observations of the study region as well as integrative data analyses, hindering a comprehensive system analysis. The fast-changing environment and ecosystem changes driven by climate change, socio-economic activities like the China Silk Road Initiative, and the global trends like urbanization further complicate such analyses. We recognize new topics with an increasing importance in the near future, especially “the enhancing biological sequestration capacity of greenhouse gases into forests and soils to mitigate climate change” and the “socio-economic development to tackle air quality issues”.

Newly identified climatically and environmentally significant high-latitude dust sources

“…Snow is also essential in the catchment areas (i.e., areas supplying watercourses) and for many snow-dependent organisms, including plants, animals, and microbes (Zhu et al, 2019). Melt can also run hydroelectric power plants that supply electricity (e.g., Lappalainen et al, 2022). This all highlights the importance of investigations and continuous assessment of the temporal and spatial significance and contribution of different light-absorbing impurities in enhancing or initiating cryospheric melt in the changing climate.…”

Institute for Atmospheric and Earth System Research (INAR): Showcases for making science diplomacy

“…The Part I of the ACP PEEX special issue (2016-2020) consists of 56 papers (acp.copernicus.org/articles/special_issue395.html). The research overview of the published ACP PEEX Part I special issue is under preparation (Lappalainen et al, 2022). The Part II of ACP PEEX special issue was opened in 2021 (acp.copernicus.org/articles/special_ issue1103.html).…”

Observations and geophysical value-added datasets for cold high mountain and polar regions

“…Awareness of the open sharing and interoperability of Earth observations and valueadded datasets has been promoted by international programs and projects; for example, the Group on Earth Observations (GEO), the GEO Cold Regions Initiative (Qiu et al, 2016;Pirazzini et al, 2020;GEO, 2022), and the Pan-Eurasian Experiment program (Lappalainen et al, 2022), as well as environmental projects concerned with polar regions, such as the Integrated Arctic Observation System (INTAROS), which is part of the EU's Horizon 2020 project (Sandven et al, 2020), and its counterpart project Multi-Parameters Arctic Environmental Observations and Information Services funded by Ministry of Science and Technology of China (MARIS); the ERA-PLANET Strand-4 Integrative and Comprehensive Understanding on Polar Environments project (iCUPE) (Petäjä et al, 2020); the CASEarth Poles project (Li et al, 2020), which is part of the Chinese Academy of Sciences Big Earth Data Science Engineering Program (Guo, 2018); the Digital Belt and Road Program Working Group on High Mountain and Cold Regions (Qiu et al, 2017); and the Third Pole Environment (Yao et al, 2012;Yao et al, 2022).…”