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CryoBioLinks: Assessing cryosphere-biosphere linkages with Earth Observations in northern high latitudes

CryoBioLinks: Assessing cryosphere-biosphere linkages with Earth Observations in northern high latitudes

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Kristin Böttcher, 1.11.2024

Climate warming in the northern high-latitudes has consequences for cryosphere conditions in the boreal zone (snow cover, soil freeze-thaw and permafrost). Cryosphere changes will subsequently affect the biosphere e.g. through changes in the carbon uptake and release by vegetation. The CryoBioLinks project aimed at improving the knowledge about these interactions and assessed the suitability of satellite-based snow melt, soil freeze and thaw observations to inform on the carbon uptake periods in boreal forests. The project determined soil freeze and thaw dates and the non-frozen period from the ESA SMOS Level 3 Soil Freeze and Thaw product (Figure 1).  Snow melt dates were estimated from the ESA cci snow cover fraction on the ground (SCFG) using the Earth System Data Lab (ESDL). Eddy covariance measurements from evergreen coniferous forest sites in Finland and Canada were used to determine carbon uptake and release periods. It was found that satellite-derived snow melt, thaw and freeze dates can provide reasonable proxies for estimating the length of the carbon uptake period in boreal forests (Figure 2).  Furthermore, results showed that year-to-year anomalies in snow melt and thaw, both from in situ and satellite observations, were correlated with the recovery of photosynthesis and ecosystem respiration in the studied boreal forest ecosystems.  Earlier snow melt and thaw were related to an increase in gross primary production and ecosystem respiration during the first six months of the year.  Future work could broaden the approach to study the influence of cryosphere dynamics on the carbon fluxes also in Arctic tundra and wetland ecosystems. 

Figure 1. The length of the non-frozen period in the northern high latitudes mapped from SMOS Freeze and Thaw observations.
Figure 2. Average seasonal cycle of gross primary production (GPP) and total ecosystem respiration (TER) for a boreal coniferous forest. Vertical lines indicate the SMOS thaw and freeze date (Black) and snow melt date from ESA ESA cci_snow Snow Cover Fraction – on the ground (SCFG) (Blue).

Publications:

Böttcher, K., Thum, T., Rautiainen, K., Aurela, M., Pulliainen, J., Plummer, S., Johnson, B., Koponen, S., Lacroix, F., and Zaehle, S. (2023). Assessing cryosphere-biosphere linkages in boreal forests with Earth Observation and modelling, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-15103, https://doi.org/10.5194/egusphere-egu23-15103, 2023.

Pulliainen, J., Aurela, M., Aalto, T., Böttcher, K., Cohen, J., Derksen, C., Heimann, M., Helbig, M., Kolari, P., Kontu, A., Krasnova, A., Launiainen, S., Lemmetyinen, J., Lindqvist, H., Lindroth, A., Lohila, A., Luojus, K., Mammarella, I., Markkanen, T., Nevala, E., Noe, S., Peichl, M., Pumpanen, J., Rautiainen, K., Salminen, M., Sonnentag, O., Takala, M., Thum, T., Vesala, T., & Vestin, P. (2024). Increase in gross primary production of boreal forests balanced out by increase in ecosystem respiration. Remote Sensing of Environment, 313, 114376, https://doi.org/10.1016/j.rse.2024.114376

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