Dr. Pete Akers

Atmospheric rivers are narrow bands of intense atmospheric moisture transport that fuel extreme precipitation events, destructive flooding, and powerful storms. Global climate models suggest that anthropogenic climate change will strengthen atmospheric rivers in the future, but despite this threat, relatively limited research has been published on Irish-impacting atmospheric river events. Project ISOTAISE will work to address this oversight with a four-year program dedicated to improving our understanding of Irish atmospheric rivers through stable isotopic monitoring and synoptic climate reanalysis. Through four work packages, ISO-TAISE will markedly advance Irish climate science through the production and open access publishing of isotopic climate data collected at resolutions unprecedented for Ireland. In the first work package, a state of the art laser isotope spectrometer will be installed to continuously analyse ambient water vapor in Dublin for the full project duration. The resulting dataset will offer 5 isotopic parameters (including the rare 17O and 17O-excess) at resolutions as fine as 5 min. Next, a review of severe atmospheric rivers affecting Ireland from 1981-2019 will identify their moisture sourcing and transport through Irish and European reanalysis climate data in order to link historical climatology of atmospheric rivers to climate projection output. The third work package complements the first by providing isotopic composition records of ~daily precipitation samples and weekly River Dodder samples from near the water vapor monitoring station. These samples, analysed on a second laser spectrometer dedicated to liquid water isotope analysis, will allow the creation of an isotopic climatology for Dublin and Ireland focused on three components of the water cycle (atmospheric water vapor, precipitation, and stream flow). For the ambitious fourth work package, the second spectrometer will be deployed in the field directly in the path of an intense atmospheric river making landfall in Ireland. This deployment will be made 1-2 days prior to a forecasted landfall, and the spectrometer will be used in conjunction with precipitation sampling to capture the full isotopic evolution of an atmospheric river in both water vapor and precipitation. This isotopic case study will provide valuable insight to meteorologists around the world regarding the moisture transport and cloud microphysics occurring during atmospheric river passage. Finally, to fully translate the findings of ISOTAISE into climate change impact, the project will produce a policy advisement document targeting policymakers that highlights actionable items learned about present and future atmospheric river risk from ISO-TAISE.

Blanket bog carbon storage and biodiversity are critical components of a sustainable Ireland, but a warming and drying climate may push blanket bogs beyond a tipping point into ecological collapse. Worryingly, the exact environmental conditions that lead to this threshold are unknown. We could constrain uncertainty about blanket bog resilience by knowing the maximum aridity levels that blanket bogs have survived in the past, but reconstructing long histories of bog aridity is challenged by the lack of a peat-sourced proxy for water lost to evapotranspiration (ET). In project DRYPEAT, we will develop a new ET proxy using deuterium-excess (dxs), a second-order stable isotopic parameter, of bog plant cellulose. In a key innovation, DRYPEAT will use the differences in cellulose dxs between non-vascular Sphagnum and other vascular bog plants to directly capture the previously unquantified transpiration component of ET. Our proxy development will be achieved through sustained monitoring of bog precipitation, surface waters, and vegetation in the Wicklow Mountains and then applied to multiple peat cores to compare past high ET periods when the bogs survived with predicted future ET extremes. DRYPEAT will thus aid Irish climate mitigation planning while also expanding the technical capacity of Irish geoscience research.