ASSESSING COASTAL VULNERABILITY IN FINLAND: A GEOINFORMATION-BASED APPROACH USING GIS

ASSESSING COASTAL VULNERABILITY IN FINLAND: A GEOINFORMATIONBASED APPROACH USING GIS IAG RCG 2025 16-18 September, Timișoara, Romania Konstantina Lymperopoulou1,2); George P. Petropoulos1); Anna Karkani2); Niki Evelpidou2); Spyridon E. Detsikas1) 1) Department of Geography, Harokopio University of Athens 2) Faculty of Geology and Geoenvironment, National and Kapodistrian University of Athens RESULTS INTRODUCTION - METHODS •Arctic is warming 2-3 times faster than global average since 1979, causing sea-level rise, ice retreat, permafrost thaw, and erosion [1]. •Finland's coastline: vulnerable due to low tides, brackish Baltic Sea, eutrophication, and variable isostatic uplift (3-9 mm/year)[2,3]. •uses geoinformation (EO, GIS) for cost-effective monitoring. •Aims: Apply CVI to assess vulnerability for sustainable management and adaptation strategies. Key Findings •CVI range: Spatial variability: 37% very low (south Gulf of Finland, Lapland parts), 27% low, 6% moderate, 29% high (central Gulf of Bothnia), 1% very high. •Geomorphology: 41% high, 25% very high (e.g., vegetated beaches vulnerable). •Coastal Slope: 100% very high (<2.5%, max 0.69%). •MWH: 24% very low, 44% low, 32% moderate (max 0.95m). •TR: 33% very low, 67% moderate. •RSL: 100% very high. •Shoreline Change: 44% moderate (±1.0 m/y). Study Area •. Finland: Northern Europe, 1/3 above Arctic Circle (Lapland, ~180,000 people)[4]. •Coastline: 1,100 km mainland + 39,000 km islands/archipelagos; geology: Precambrian rocks, glaciation features (moraines, eskers)[5,6]. •Challenges: Erosion, storm surges, urban/tourism pressures Methods •CVI formula: CVI = √(a × b × c × d × e × f) / 6 (a=geomorphology, b=shoreline erosion/accretion, c=coastal slope, d=relative sea-level change, e=mean wave height, f=tidal range). •Data sources: CVI Variables Source Reference Period Mean Wave Height (m) [7] 1979-2018 Relative Sea Level change (mm/y) [8] IPCC 2100 Tidal Range (m) [9] 1992-2008 Coastal slope National Land Survey of Finland DEM https://asiointi.maanmittauslaitos.fi/karttapa ikka/?lang=en (accessed on 25 January 2025). - Geomorphol ogy EMODnet Geology / coastal type https://emodnet.ec.europa.eu/geoviewer/#!/ (accessed on 5 May 2025). - Shoreline erosion/ accretion (m/y) EMODnet Geology / coastal migration / satellite data https://emodnet.ec.europa.eu/geoviewer/#!/ (accessed on 5 May 2025). 20072017 •Preprocessing: Coastline split into >90,000 segments; Thiessen polygons for interpolation; slope as % from DEM (grid 10m x 10m, accuracy 1.4m). •Tools: ArcGIS Pro; data from EMODnet, Ranking: CVI Very Low Low Moderate High Very High Variables 1 2 3 4 5 Geomorpholog y Rocky, cliffed coasts, Fiords, Fiards Artificial Construction s Medium Cliffs, indented coasts Low cliffs, glacial drift, alluvial plains, beachrocks , dunes (mixed material) Cobble beaches, Estuaries, Lagoons Barrier beaches, Sand beaches, Salt marshes, Mud flats, Deltas, Mangroves, Coral reefs Coastal Slope % >20 720 47 2.54 <2.5 RSL (mm/y) <1.8 1.82.5 2.53.0 3.03.2 >3.2 Tidal Range (m) >6.0 4.16.0 2.04.0 1.01.9 <1.0 Mean Wave Height (m) <0.55 0.550.85 0.851.05 1.051.25 >1.25 Shoreline erosion/ accretion(m/yr ) >2.0 1.02.0 -1.01.0 -1.1- - 2.0 <- 2.0 RESULTS DISCUSSION Figure 2: Bar chart of % vulnerability per parameter. Figure 3: Spatial CVI map of Finland's coastline. Figure 4: Pie chart of overall CVI classes e) f) a) b) c) d) Figure 3: Vulnerability classification maps: (a) geomorphology, (b) coastal slope, (c) MWH, (d) TR, (e) RSL, (f) SH change. The CVI is effective in revealing spatial variations in Finland's coastal risks, driven by factors such as geomorphology, coastal slope, mean wave height, tidal range, relative sea-level change, and shoreline change. It notes that while southern and some northern regions exhibit low vulnerability due to higher elevations, archipelagos, and limited wave action, central areas, particularly in the Gulf of Bothnia, face higher risks, aligning with prior studies on similar Baltic Sea environments. Key vulnerabilities stem from high geomorphology risks (66% in high or very high categories), universally very high coastal slopes below 2.5%, and dominant relative sea-level change threats, despite post-glacial rebound. Limitations include data temporal inconsistencies, challenges in high-resolution geospatial acquisition, equal parameter weighting potentially overlooking Finland-specific conditions, and the absence of sensitivity analysis, suggesting needs for refined models, socioeconomic integration, and field validation to enhance accuracy. DOI: https://doi.org/10.3390/land14091741 •. Table 1. Data sources used in CVI calculations in this study. Table 2. CVI variables ranking according to Thieler and Hammar-Klose [10]. Figure 1: Geographic Context and shoreline of Finland CONCLUSION Funding: The present research study has been financially supported by the project “EO-PERSIST”, funded by the European Union’s Horizon Europe research and innovation program (HORIZONMSCA-2021-SE-01-01, under grant agreement no. 101086386). Contact: Author emails & and the published paper at the QR code. License: © 2025 by the authors. Open access under CC BY 4.0 Scan to read the paper The study establishes a baseline for Finland's coastal vulnerability using the CVI, emphasizing low overall risks in parameters like mean wave height and tidal range, but elevated concerns from geomorphology, slope, and sealevel rise, with 37% of the coastline classified as very low vulnerability and 29% as high. It recommends future research focusing on improved temporal data fusion, socioeconomic factors, automated geomorphological classification, and field validations to refine assessments. Ultimately, the work underscores the CVI's value as a replicable tool for Arctic regions, aiding sustainable management, infrastructure planning, and climate resilience in Finland's unique coastal setting through geoinformation technologies REFERENCES 1. Intergovernmental Panel on Climate Change (IPCC). Special Report on the Ocean and Cryosphere in a Changing Climate; IPCC: Geneva, Switzerland, 2019. 2. HELCOM. 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