Strong mesoscale haboob dust storms in April 2007 in the central Arabian Peninsula were studied using the cloud‐resolving Weather Research and Forecasting‐Chemistry (WRF‐Chem) modeling system and observations collected during an intensive atmospheric field campaign. The field campaign provided the valuable aircraft and Doppler weather radar measurements. Active convection persisted for several days during the study period. Dust generation was caused by both strong large‐scale winds and locally produced density currents. Because of insufficient spatial resolution, the event was not resolved accurately by the conventional reanalyses. However, the WRF‐Chem model did successfully capture the primary features of the convection, its location, and precipitation patterns. Although the amount of rainfall in the model was slightly underestimated compared to the satellite measurements, it was approximately double the rainfall in the reanalysis. The convection‐associated dust outbreaks were simulated well, with the aerosols optical depth magnitude and the temporal variability being in good agreement with both the ground‐based and satellite aerosol retrievals. The model captured the major dust generation patterns, transport pathways, and several of the largest haboobs identified from the satellite observations. About 25 Tg of dust was emitted in the Arabian Peninsula during the 10‐day period. Approximately 40% of the locally deposited dust was subject to wet removal processes. During periods of high local dust production, the WRF‐Chem model underestimated the PM₁₀ mass concentration (associated mostly with dust particles larger than 3 μm in diameter) by nearly a factor of 2. This suggests that the current dust parameterizations, which prescribe the size distribution of the emitted dust, underestimate the number of large particles that increases at strong wind conditions.

Underwater time-lapse video technology has been used to monitor adult spring and summer chinook salmon (Oncorhynchus tshawytscha) escapement into the Secesh River and Lake Creek, Idaho, since 1998. Underwater time-lapse videography is a passive methodology that does not trap or handle this Endangered Species Act listed species. Secesh River chinook salmon represent a wild spawning aggregate that has not been directly supplemented with hatchery fish. The Secesh River is also a control population under the Idaho Salmon Supplementation study. This project has demonstrated the successful application of underwater video adult salmon abundance monitoring technology in Lake Creek in 1998 and 1999. Emphasis of the project in 2000 was to determine if the temporary fish counting station could be installed early enough to successfully estimate adult spring and summer chinook salmon abundance in the Secesh River (a larger stream). Snow pack in the drainage was 93% of the average during the winter of 1999/2000, providing an opportunity to test the temporary count station structure. The temporary fish counting station was not the appropriate technology to determine adult salmon spawner abundance in the Secesh River. Due to its temporary nature it could not be installed early enough, due to high stream discharge,more » to capture the first upstream migrating salmon. A more permanent structure used with underwater video, or other technology needs to be utilized for accurate salmon escapement monitoring in the Secesh River. A minimum of 813 adult chinook salmon spawners migrated upstream past the Secesh River fish counting station to spawning areas in the Secesh River drainage. Of these fish, more than 324 migrated upstream into Lake Creek. The first upstream migrating adult chinook salmon passed the Secesh River and Lake Creek sites prior to operation of the fish counting stations on June 22. This was 17 and 19 days earlier than the first fish arrival at Lake Creek in 1998 and 1999 respectively. Peak net upstream adult movement at the Secesh River site occurred June 28 and at the Lake Creek site on June 27. Peak of total movement was August 16 at Secesh River and August 7 at Lake Creek. The last fish passed through the Lake Creek fish counting station on August 31 and on September 8 at the Secesh River site. Migrating salmon in the Secesh River and Lake Creek exhibited two behaviorally distinct segments of fish movement. The first segment of movement was characterized, mainly, by upstream movement only. The second segment consisted of upstream and downstream movement with very little net upstream movement. The fish counting stations did not impede salmon movements, nor was spawning displaced downstream. Fish moved freely upstream and downstream through the fish counting structures. Fish movement was greatest between the period of 5:00 p.m. and 4:00 a.m. There appeared to be a segment of ''nomadic'' males that moved into and out of the spawning area, apparently seeking other mates to spawn with. The downstream movement of salmon allowed by this fish counting station design may be an important factor affecting reproductive success as male salmon seek other females to spawn with. Traditional weirs operated for broodstock collection do not allow for downstream movement of adults. This methodology has the potential to provide more consistent and accurate salmon spawner abundance information than single-pass and multiple-pass spawning ground surveys. Accurate adult abundance would allow managers to determine if recovery actions were benefiting these salmon spawning aggregates and if recovery goals were being met. « less

Antarctica InSync is a global effort to synchronise research across Antarctica and the Southern Ocean, connecting ice, ocean, land, climate, and life to protect this vital region. This roadmap paper introduces the scientific and technological motivation and action plan to build an international programme for a coordinated field season in Antarctica and its surrounding seas. It lays out the international collaboration that is required to realise an ambitious action plan and the opportunities for the science community to address important scientific themes that identify current knowledge gaps. In the spirit of the Antarctic Treaty Consultative Meeting (ATCM), the planned scientific action mandates free data exchange, facilitates international collaboration, and derives expert scientific advice together with the Scientific Committee on Antarctic Research (SCAR). Aligned with challenges of the United Nation Ocean and Cryosphere Decades, we plan a shared global effort to better understand the role of Antarctica and its surrounding ocean for our global futures, building on decades of achievements in polar and ocean science. As a milestone leading up to the next International Polar Year in 2032/33 (IPY5), the ambition is to achieve a new level of cooperation, with opportunities for the next generation of polar scientists around the world by enhancing practices in sharing of ideas, infrastructure and information.

Antarctica is changing faster than our current observation networks can robustly assess or predict. Recent extreme events – major ice-shelf collapse, unprecedented heatwaves and abrupt, record-low winter sea ice – show that rare extremes can rapidly reshape the Antarctic system. These changes matter well beyond the polar regions: Antarctica influences global sea level, ocean circulation, and the whole climate system. This white paper sets out the case for Antarctica InSync (2027–2030) to deliver a four-year, coordinated observational baseline ahead of the International Polar Year 2031/32, so it is possible to distinguish temporary anomalies from long-term shifts, detect early warning signs of tipping points, and improve the evidence base for risk management. The result is more reliable projections, better attribution of drivers, and earlier detection of destabilising trajectories – directly supporting policy decisions on climate adaptation, coastal planning, and the design of international monitoring commitments, specifically targeting the following four focus areas bridging ocean-atmosphere-ice interactions and climate variability: • Snow, firn and SMB: Fund coordinated field and satellite-calibration measurements to reduce the largest uncertainty in sea-level projections: how snowfall, melt, refreezing and runoff will change. • Atmosphere and water cycle: Expand weather, precipitation and water-isotope observations to track storms and moisture transport inland – essential for forecasting extremes and future snowfall/rainfall shifts. • Ocean–sea ice–atmosphere coupling: Invest in marginal-ice-zone and ice shelves fronts observations to understand how sea-ice loss and ocean warming amplify extremes, alter heat/moisture exchange, destabilise ice shelves and weaken deep-water formation. • Variability and warming detection: Combine new observations and ice-core and marine records to separate human-driven trends from natural variability and identify early warning signals of irreversible change.