Integrating surface-atmosphere Exchange Processes Across Scales - Modeling and Monitoring (IPAS)
Scales play an important role for the analysis and interpretation of climate-relevant feedback processes between biosphere and atmosphere. Particularly for highly structured domains such as Arctic permafrost landscapes, to accurately predict large-scale, long-term changes in ecosystem functionality, we need to investigate processes at fine-scales to understand the drivers of these changes. Also, new observational insight into links between ecosystem characteristics and carbon and energy processes needs to be assimilated into flexible modeling frameworks, ideally combining the individual advantages of different modeling philosophies.
Our working group integrates multi-disciplinary observational and modeling approaches, currently with a regional focus on Arctic permafrost landscapes. The monitoring techniques cover scales ranging from a few centimeters (e.g. soil cores) to thousands of kilometers (e.g. atmospheric trace gas mixing ratios), with a strong focus on atmospheric observations but also including disciplines such as hydrology and soil science. On the modeling site, the IPAS group customizes process-based biogeochemical models, data-driven statistical modeling and atmospheric inverse modeling techniques for application in high-latitude permafrost environments, with the overarching objective of combining their individual strengths, and assimilating the newly generated datasets.
Focus #1: Investigation of carbon-climate feedbacks in high-latitude ecosystems
A core element of this line of research is a permafrost observatory that our group established in 2013 near Chersky, Northeast Siberia. At this site, we investigate with continuous observations the impact of a sustained drainage disturbance through multi-disciplinary observations (e.g. Göckede et al., GCB 2019). Additional Arctic observations include the atmospheric monitoring site Ambarchik and measuring grazing disturbance effects in the Pleistocene Park area near Chersky. New process insights are assimilated into process models (e.g. Castro-Morales et al., BG 2019) to improve projections of Arctic permafrost sustainability under future climate trajectories.
Focus #2: Methane observations and modeling across scales
On the observational side, we have placed a focus on developing quality assessment measures for methane flux observations, e.g. involving wavelet tools (Göckede et al., BG 2019) and footprint modeling. Modeling focuses on constraining regional scale methane budgets with atmospheric inverse methods, with a particular emphasis on linking top-down and bottom-up modeling for the evaluation of process model performance. This research is embedded within the framework of an international working group on Understanding and Predicting Wetland Methane Emissions, coordinated by the USGS Powell Center.
Focus #3: Evaluation of Arctic atmospheric greenhouse gas monitoring networks
Our group has put together a metadata survey on the current status of Arctic eddy-covariance flux towers, flux chamber sites, and tall monitoring towers for calibrated atmospheric greenhouse gas mixing ratios, which is available as a web-tool hosted by NCEAS. Based on the site information, we evaluate the representativeness of the network of eddy-covariance flux towers to capture the variability in carbon fluxes across pan-Arctic ecosystems (e.g. Pallandt et al., BG 2022), and evaluate what signals related to current and future permafrost ecosystem disturbance could reliably be monitored by the pan-Arctic network of tall towers, in combination with atmospheric inverse modeling.