ALBERT

Description: Arctic warming is affecting snow cover and soil hydrology, with consequences for carbon sequestration in tundra ecosystems. The scarcity of observations in the Arctic has limited our understanding of the impact of covarying environmental drivers on the carbon balance of tundra ecosystems. In this study, we address some of these uncertainties through a novel record of 119 site-years of summer data from eddy covariance towers representing dominant tundra vegetation types located on continuous permafrost in the Arctic. Here we found that earlier snowmelt was associated with more tundra net CO2 sequestration and higher gross primary productivity (GPP) only in June and July, but with lower net carbon sequestration and lower GPP in August. Although higher evapotranspiration (ET) can result in soil drying with the progression of the summer, we did not find significantly lower soil moisture with earlier snowmelt, nor evidence that water stress affected GPP in the late growing season. Our results suggest that the expected increased CO2 sequestration arising from Arctic warming and the associated increase in growing season length may not materialize if tundra ecosystems are not able to continue sequestering CO2 later in the season.

Description: The term "space weather" summarizes phenomena in the solar system that originate from the sun and can affect modern technological infrastucture - including disturbances of navigation systems (e.g. GNSS), problems in power supply operation, as well as the loss of radio communication. The SWAP (Space Weather: The Austrian Platform) project deals with the diffusion of space weather information and expertise to potential users and the public. Funded as part of the Austrian Space Applications Programme (FFG), the project is carried out by a consortium of eight partners in space weather research and application. Our aims are to (1) create a network of national experts in the field, (2) establish a national space weather platform, and (3) plot a road map for future development in Austria. In this presentation, we will provide an overview on our progress in developing a national platform. A newly established website serves as a single point of entry into the topic of space weather in Austria. We use this platform as a launchpad to contact potential stakeholders and provide a resource of combined space weather expertise, with the intent to extend awareness of space weather events and their potential consequences. Using a space weather “atlas”, the website ties together the existing expertise with space weather topics. A direct line of contact to the relevant experts is provided in case of extreme events. We have identified various stakeholders including regional warning centres, power grid operators, groups relying on GPS and radio signals, and the press, among others.

Description: Tsunamis are one of the most devastating natural disasters, causing widespread destruction and loss of life. In recent years, advances in science and technology have led to the development of sophisticated tsunami early warning systems, with promising operational applications. However, much work remains to be done in order to further improve the accuracy and timeliness of warning systems, and for enhancing the preparedness of at-risk communities. In December 2017, the U.N. proclaimed the Decade of Ocean Science for Sustainable Development (2021–2030), also referred to as the Ocean Decade. The Ocean Decade Tsunami Programme (ODTP) approved by the UNESCO IOC in 2021 in response to the call to Ocean Decade action provides an excellent framework for international cooperation to enhance the end-to-end tsunami early warning and mitigation systems. The main objectives of the ODTP are (i) to develop the warning systems’ capability to issue actionable and timely tsunami warnings for tsunamis from all identified sources to 100% of coasts at risk and (ii) 100% of communities at risk to be prepared and resilient to tsunamis by 2030 through programmes like the UNESCO IOC Tsunami Ready Recognition Programme. A Research, Development and Implementation Plan is being prepared by the ODTP Science Committee highlighting the goals, status, challenges, potential solutions and implementation pathways for enhancing (i) risk knowledge, (ii) detection, analysis and forecasting, (iii) warning dissemination and communication, and (iv) preparedness and response capabilities. The plan also highlights capacity development needs, governance aspects and international cooperation in achieving the objectives of the ODTP.

Description: Long-term atmospheric CO2 concentration records have suggested a reduction in the positive effect of warming on high-latitude carbon uptake since the 1990s. A variety of mechanisms have been proposed to explain the reduced net carbon sink of northern ecosystems with increased air temperature, including water stress on vegetation and increased respiration over recent decades. However, the lack of consistent long-term carbon flux and in situ soil moisture data has severely limited our ability to identify the mechanisms responsible for the recent reduced carbon sink strength. In this study, we used a record of nearly 100 site-years of eddy covariance data from 11 continuous permafrost tundra sites distributed across the circumpolar Arctic to test the temperature (expressed as growing degree days, GDD) responses of gross primary production (GPP), net ecosystem exchange (NEE), and ecosystem respiration (ER) at different periods of the summer (early, peak, and late summer) including dominant tundra vegetation classes (graminoids and mosses, and shrubs). We further tested GPP, NEE, and ER relationships with soil moisture and vapor pressure deficit to identify potential moisture limitations on plant productivity and net carbon exchange. Our results show a decrease in GPP with rising GDD during the peak summer (July) for both vegetation classes, and a significant relationship between the peak summer GPP and soil moisture after statistically controlling for GDD in a partial correlation analysis. These results suggest that tundra ecosystems might not benefit from increased temperature as much as suggested by several terrestrial biosphere models, if decreased soil moisture limits the peak summer plant productivity, reducing the ability of these ecosystems to sequester carbon during the summer.