ALBERT

Description: Abstract Increasingly knowledge is shared using new web‐based channels. The use of these channels is relatively new in the realm of soil science. However, they may prove to be very useful for connecting time‐poor, geographically dispersed audiences in an efficient and cost‐effective way. There has been limited study of this form of knowledge sharing for natural science (let alone soil science). In New South Wales (NSW), Australia, the NSW Department of Primary Industries (NSW DPI) has coordinated the Soil Network of Knowledge (SNoK) monthly webinar over 3 years, with over 40 webinars targeting an audience of next users of soil information. Aggregated data collected from these webinars indicated that the majority of information is used for professional development by participants. Whether this will eventually lead to on‐ground practice change because of the improved professional and technical knowledge of participants is still a moot point and will require further investigation over time. The information collected on attendance and participation showed that webinars are a good way to connect with some target audiences such as other government bodies that have a historical relationship with NSW DPI. However, other target audiences that NSW DPI has always found difficulty in engaging, such as private advisers, require more active overtures to drive participation. The growing subscriber base is encouraging.

Description: The revegetation of cleared landscapes with woody plants (termed “environmental planting”) has the potential to sequester carbon (C), provide habitat, and increase biodiversity and connectivity. These environmental values are potentially offset by an increased fire hazard posed by revegetation. There is a need to understand the influence environmental planting has on landscape fire behavior and to determine how this changes as plantings age. This study examined how environmental values, regenerative capacity, fuel metrics, and potential fire behavior change with time since planting. We assessed 57 sites across the Albury-Wodonga region (New South Wales, Australia). This included a range of environmental planting ages (4–40 yr time since planting), remnants, and pastures. Carbon storage increased with age of planting, with largest C stores found in remnants (105 tC/ha), while habitat complexity plateaued around 20 yr, with no significant difference between moderately aged plantings (14–20 yr), old plantings (〉20 yr), and remnants. Modeled rate of fire spread was faster in pastures compared to environmental plantings and remnants. Flame height was slightly higher (0.5–1 m) in pastures than environmental plantings and remnants under a Very High Forest Fire Danger Index (FFDI), but this trend reversed under Extreme and Catastrophic conditions with flame heights greatest in environmental plantings and remnants albeit with slower rates of spread. This research highlights the importance of environmental plantings in the landscape in terms of C storage and environmental values and indicates the perceived hazard associated with rate of spread and flame height may not be justified at or less than Very High FFDI. However, at FFDI greater than Very High fire behavior may be significantly enhanced in environmental plantings and remnants. Further consideration needs to be given to the size and design of plantings and the type of species planted to fully develop an understanding of the complexities of fire risk. This study allows land managers to make informed decisions regarding the values and risks associated with revegetation of cleared landscapes with woody plants.

Description: Carbon dioxide ($ext{CO}_{2}$) capture and subsurface storage is one method for reducing anthropogenic $ext{CO}_{2}$ emissions to mitigate climate change. It is well known that large-scale fluid injection into the subsurface leads to a buildup in pressure that gradually spreads and dissipates through lateral and vertical migration of water. This dissipation can have an important feedback on the shape of the $ext{CO}_{2}$ plume during injection, but the impact of vertical pressure dissipation, in particular, remains poorly understood. Here, we investigate the impact of lateral and vertical pressure dissipation on the injection of $ext{CO}_{2}$ into a layered aquifer system. We develop a compressible, two-phase model that couples pressure dissipation to the propagation of a $ext{CO}_{2}$ gravity current. We show that our vertically integrated, sharp-interface model is capable of efficiently and accurately capturing water migration in a layered aquifer system with an arbitrary number of aquifers. We identify two limiting cases – ‘no leakage’ and ‘strong leakage’ – in which we derive analytical expressions for the water pressure field for the corresponding single-phase injection problem. We demonstrate that pressure dissipation acts to suppress the formation of an advancing $ext{CO}_{2}$ tongue during injection, reducing the lateral extent of the plume. The properties of the seals and the number of aquifers determine the strength of pressure dissipation and subsequent coupling with the $ext{CO}_{2}$ plume. The impact of pressure dissipation on the shape of the $ext{CO}_{2}$ plume is likely to be important for storage efficiency and security.

Description: Equatorial East Africa (EEA) suffers from significant flood risks. These can be mitigated with pre-emptive action, however currently available early warnings are limited to a few days lead time. Extending warnings using subseasonal climate forecasts could open a window for more extensive preparedness activity. However before these forecasts can be used, the basis of their skill and relevance for flood risk must be established. Here we demonstrate that subseasonal forecasts are particularly skillful over EEA. Forecasts can skillfully anticipate weekly upper quintile rainfall within a season, at lead times of two weeks and beyond. We demonstrate the link between the Madden-Julian Oscillation (MJO) and extreme rainfall events in the region, and confirm that leading forecast models accurately represent the EEA teleconnection to the MJO. The relevance of weekly rainfall totals for fluvial flood risk in the region is investigated using a long record of streamflow from the Nzoia river in Western Kenya. Both heavy rainfall and high antecedent rainfall conditions are identified as key drivers of flood risk, with upper quintile weekly rainfall shown to skillfully discriminate flood events. We additionally evaluate GloFAS global flood forecasts for the Nzoia basin. Though these are able to anticipate some flooding events with several weeks lead time, analysis suggests action based on these would result in a false alarm more than 50% of the time. Overall, these results build on the scientific evidence base that supports the use of subseasonal forecasts in EEA, and activities to advance their use are discussed.