Trans-equatorial migration routes, staging sites and wintering areas of a High-Arctic avian predator: The long-tailed skua (Stercorarius longicaudus)

first_imgThe Long-tailed Skua, a small (<300 g) Arctic-breeding predator and seabird, is a functionally very important component of the Arctic vertebrate communities in summer, but little is known about its migration and winter distribution. We used light-level geolocators to track the annual movements of eight adult birds breeding in north-east Greenland (n = 3) and Svalbard (n = 5). All birds wintered in the Southern Hemisphere (mean arrival-departure dates on wintering grounds: 24 October-21 March): five along the south-west coast of Africa (0–40°S, 0–15°E), in the productive Benguela upwelling, and three further south (30–40°S, 0–50°E), in an area extending into the south-west Indian Ocean. Different migratory routes and rates of travel were documented during post-breeding (345 km d−1 in late August-early September) and spring migrations (235 km d−1 in late April) when most birds used a more westerly flyway. Among the different staging areas, a large region off the Grand Banks of Newfoundland appears to be the most important. It was used in autumn by all but one of the tracked birds (from a few days to three weeks) and in spring by five out of eight birds (from one to more than six weeks). Two other staging sites, off the Iberian coast and near the Azores, were used by two birds in spring for five to six weeks. Over one year, individuals travelled between 43,900 and 54,200 km (36,600–45,700 when excluding staging periods) and went as far as 10,500–13,700 km (mean 12,800 km) from their breeding sites. This study has revealed important marine areas in both the south and north Atlantic Ocean. Sustainable management of these ocean basins will benefit Long-tailed Skuas as well as other trans-equatorial migrants from the Arctic.last_img read more

Electron acceleration at Jupiter: greater input from cyclotron-resonant interaction with whistler-mode chorus waves

first_imgJupiter has the most intense radiation belts of all the outer planets. It is not yet known how electrons can be accelerated to energies of 10 MeV or more. It has been suggested that cyclotron-resonant wave-particle interactions by chorus waves could accelerate electrons to a few MeV near the orbit of Io. Here we use the chorus wave intensities observed by the Galileo spacecraft to calculate the changes in electron flux as a result of pitch angle and energy diffusion. We show that, when the bandwidth of the waves and its variation with L are taken into account, pitch angle and energy diffusion due to chorus waves is a factor of 8 larger at L-shells greater than 10 than previously shown. We have used the latitudinal wave intensity profile from Galileo data to model the time evolution of the electron flux using the British Antarctic Survey Radiation Belt (BAS) model. This profile confines intense chorus waves near the magnetic equator with a peak intensity at ∼5° latitude. Electron fluxes in the BAS model increase by an order of magnitude for energies around 3 MeV. Extending our results to L = 14 shows that cyclotron-resonant interactions with chorus waves are equally important for electron acceleration beyond L = 10. These results suggest that there is significant electron acceleration by cyclotron-resonant interactions at Jupiter contributing to the creation of Jupiter’s radiation belts and also increasing the range of L-shells over which this mechanism should be considered.last_img read more

Dynamical Response to the QBO in the Northern Winter Stratosphere: Signatures in Wave Forcing and Eddy Fluxes of Potential Vorticity

first_imgWave–mean flow interactions associated with the Holton–Tan effect (HTE), whereby the tropical quasi-biennial oscillation (QBO) modulates the Northern Hemisphere wintertime stratospheric polar vortex, are studied using the ERA-Interim dataset. Significant evidence of the HTE in isentropic coordinates is found, with a weaker and warmer polar vortex present when the lower-stratospheric QBO is in its easterly phase (QBOe). For the first time, the authors quantify the QBO modulation of wave propagation, wave–mean flow interaction, and wave decay/growth via a calculation of potential vorticity (PV)-based measures, the zonal-mean momentum budget, and up-/downgradient eddy PV fluxes. The effect of the tropospheric subtropical jet on QBO modulation of the wave activity is also investigated. In the subtropical-to-midlatitude lower stratosphere, QBOe is associated with an enhanced upward flux of wave activity, and corresponding wave convergence and wave growth, which leads to a stronger poleward zonal-mean meridional circulation and consequently a warmer polar region. In the middle stratosphere, QBOe is associated with increased poleward wave propagation, leading to enhanced wave convergence and in situ wave growth at high latitudes and contributing to the weaker polar vortex. In agreement with recent studies, the results suggest that the critical-line effect cannot fully account for these wave anomalies associated with the HTE. Instead, it is suggestive of a new, additional mechanism that hinges on the QBO-induced meridional circulation effect on the latitudinal positioning of the subtropical jet. Under QBOe, the QBO-induced meridional circulation causes a poleward shift of the subtropical jet, encouraging more waves to propagate into the stratosphere at midlatitudes.last_img read more

Historical and projected changes in the Southern Hemisphere Sub-tropical Jet during winter from the CMIP5 models

first_imgWe present projected changes in the speed and meridional location of the Subtropical Jet (STJ) during winter using output of the Coupled Model Intercomparison Project Phase 5 (CMIP5) models. We use the ERA-Interim reanalysis dataset to evaluate the historical simulations of the STJ by 18 of the CMIP5 models for the period 1979–2012. Based on the climatology of the STJ from ERA-Interim, we selected the area of study as 70°E–290°E and 20°S–40°S, which is over the Indian and Southern Pacific Oceans, and 300–100 hPa to reduce altitude-related bias. An assessment of the ability of the CMIP5 models in simulating ENSO effects on the jet stream were carried out using standardized zonal wind anomalies at 300–100 hPa. Results show that 47 % of the CMIP5 models used in this study were able to simulate ENSO impacts realistically. In addition, it is more difficult for the models to reproduce the observed intensity of ENSO impacts than the patterns. The historical simulations of the CMIP5 models show a wide range of trends in meridional movement and jet strength, with a multi-model mean of 0.04° decade−1 equatorward and 0.42 ms−1 decade−1 respectively. In contrast to the ERA-Interim analysis, 94 % of the CMIP5 models show a strengthening of the jet in the historical runs. Variability of the jet strength is significantly (5 %) linked to the sea surface temperature changes over the eastern tropical Pacific. The CMIP5 model projections with Representative Concentration Pathways (RCPs) 4.5 and 8.5 were used for analysis of changes of the STJ for the period 2011–2099. Based on the RCP 4.5 (RCP 8.5) scenario the multi-model mean trend of the 18 CMIP5 models project a statistically significant (5 % level) increase in jet strength by the end of the century of 0.29 ms−1 decade−1 (0.60 ms−1 decade−1). Also, the mean meridional location of the jet is projected to shift poleward by 0.006° decade−1 (0.042° decade−1) in 2099 during winter, with the only significant (5 %) trend being with RCP 8.5.last_img read more

Lagrangian ocean analysis: fundamentals and practices

first_imgLagrangian analysis is a powerful way to analyse the output of ocean circulation models and other ocean velocity data such as from altimetry. In the Lagrangian approach, large sets of virtual particles are integrated within the three-dimensional, time-evolving velocity fields. Over several decades, a variety of tools and methods for this purpose have emerged. Here, we review the state of the art in the field of Lagrangian analysis of ocean velocity data, starting from a fundamental kinematic framework and with a focus on large-scale open ocean applications. Beyond the use of explicit velocity fields, we consider the influence of unresolved physics and dynamics on particle trajectories. We comprehensively list and discuss the tools currently available for tracking virtual particles. We then showcase some of the innovative applications of trajectory data, and conclude with some open questions and an outlook. The overall goal of this review paper is to reconcile some of the different techniques and methods in Lagrangian ocean analysis, while recognising the rich diversity of codes that have and continue to emerge, and the challenges of the coming age of petascale computing.last_img read more

Multi-scale assessment of distribution and density of procellariiform seabirds within the Northern Antarctic Peninsula marine ecosystem

first_imgThe Antarctic Peninsula is one of the most rapidly warming regions on earth, and it is likely that the abundance and distribution of marine predators will change as a result.Procellariiform seabirds are highly mobile predators, which target specific habitat characteristics associated with underlying distributions of prey and areas of increased prey availability. We use ship surveys and hurdle models, to estimate the summer distribution and relative density of 11 seabird species within the northern Antarctic Peninsula marine ecosystem. Models differed among species; however, sea surface temperature and depth were frequently associated with seabird occurrence and had the greatest explanatory power across many species. Null models based on observation data were better at predicting seabird density than models that included environmental covariates. This suggests that the main driver of distribution patterns is the broad-scale habitat features, and fine-scale aggregations within these ranges are harder to predict. Our seabird distribution models reflect known habitat associations, species hotspots, and community organization relative to oceanic and coastal marine processes. Application of species distribution models will benefit the assessments of critical habitat and potential responses to climate change and anthropogenic disturbance, which will provide insight into how species may change in polar ecosystems.last_img read more

Mitchell scores 38, Jazz beat Thunder 96-91 to win series

first_imgApril 28, 2018 /Sports News – Local Mitchell scores 38, Jazz beat Thunder 96-91 to win series Associated Press FacebookTwitterLinkedInEmailSALT LAKE CITY (AP) — Donovan Mitchell scored 38 points and the Utah Jazz held off the Oklahoma City Thunder 96-91 in Game 6 on Friday night to advance to the Western Conference semifinals.Russell Westbrook had 46 points for the Thunder and Steven Adams added 19 points and 16 rebounds.The rookie and the MVP went back and forth in the second half, with Mitchell and the Jazz moving on to face the top-seeded Houston Rockets in a series that starts Sunday.Derrick Favors scored 13 points and Rudy Gobert had 12 points and 13 rebounds for the Jazz, who lost starting point guard Ricky Rubio to a left hamstring injury in the first quarter.The Jazz took their biggest lead when Gobert hit two free throws to make it 86-73 with 7:04 remaining.Westbrook’s 3-pointer capped an 18-6 run and drew Oklahoma City to 92-91 with 1:28 to play.Favors hit a jumper for the Jazz but then the Thunder corralled five offensive rebounds in a frantic set of possessions where Oklahoma City missed five shots. After a review, Paul George faked Gobert into the air behind the 3-point line and leaned in but didn’t get the call and shot an airball.Mitchell scampered down the court as the Thunder yelled at the officials and eventually made two free throws with 6.9 seconds left to clinch the game.After struggling to score in the first two periods, the Jazz just gave the ball to Mitchell and set screen after screen to allow him to take advantage of Oklahoma City’s switching defense.In the third quarter, Mitchell scored 22 points to boost the Jazz into a double-digit lead. The rookie scored on electrifying drives to the basket, spinning shots in the lane and rainbow 3-pointers.The arena, awash in gold as the Jazz wore their yellow jerseys and every fan was given a gold T-shirt, roared as Mitchell held his arms aloft and beckoned for more.Mitchell picked up his fifth foul with 10:01 to play but returned to finish the game midway through the fourth quarter.Seven minutes into the game, Rubio began limping and left the game.Facing a team without a true point guard, the Thunder extended their defense and disrupted Utah’s sets. The Jazz were shooting from unfamiliar spots and connected on just 39 percent in the first half.Oklahoma City led by as many as nine before the Jazz tied it at 41 at halftime.TIP-INSThunder: Jerami Grant made his first two 3-pointers of the series, the only Thunder player to make one besides Westbrook. … Other than a technical, the Thunder shot their first free throw with 6:36 left in the half. … George had a playoff-low five points.Jazz: Gobert got a technical foul in the second quarter for complaining. … Favors went 1 for 7 from the free throw line and the Jazz shot 12 of 23 overall. … Mitchell joins Lew Alcindor as the only rookies to score 20 points in each of their first six career playoff games over the last 50 years. … Coming into the game, Mitchell and LeBron James shared the lead for most fourth-quarter points in the playoffs so far. Tags: Basketball/Donovan Mitchell/NBA/NBA Playoffs/Oklahoma City Thunder/Utah Jazz Written bylast_img read more

Various Utah-Based Schools Ranked Highly In Cross Country Polls

first_imgSeptember 18, 2018 /Sports News – Local Various Utah-Based Schools Ranked Highly In Cross Country Polls Written by Brad James Tags: BYU/New Mexico/Northern Arizona/Providence/Southern Utah/USTFCCCA/Utah/Utah State FacebookTwitterLinkedInEmailNEW ORLEANS-Tuesday, the U.S. Track and Field and Cross Country Coaches Association (USTFCCCA) announced their latest rankings for Division I men’s and women’s cross country teams.Several Utah-based schools are among those ranked.For the men, Northern Arizona is the current #1 team in the land, gaining 330 points in the polls. BYU’s men are second with 315 points. The Southern Utah men check in at #15, while Utah State received votes in the polls. Roughly, the Aggies are the #37 team in the land per the polls.For the women, New Mexico is ranked #1 with 330 points and BYU is tied for 11th nationally with Providence. Both the Cougars and Friars have 197 points in the polls.The Utah State women are ranked 15th nationally with 182 points and Utah earned votes for the polls. Based on where they received their recognition, the Utes are 34th in the land.last_img read more

Haws scores 34, BYU turns back Pepperdine 87-76

first_imgJanuary 18, 2019 /Sports News – Local Haws scores 34, BYU turns back Pepperdine 87-76 FacebookTwitterLinkedInEmailMALIBU, Calif. (AP) — TJ Haws scored a career high with 34 points and matched his best with eight assists and BYU pulled away to defeat Pepperdine 87-76 on Thursday night. Eric Cooper Jr. hit a 3-pointer with 3:10 to play to pull the Waves within 76-73 but Haws made eight free throws and Childs had a 3-point play to close it out. Pepperdine missed its last four shots. Ross had 24 points for the Waves (9-10, 2-3) and Edwards had 22. There were 16 ties and 10 lead changes. Pepperdine’s last lead was 57-56 with 10:36 to go when Kameron Edwards converted a 3-point play to cap a 6-0 run. Colbey Ross made a pair of free throws for the Waves to tie the game at 62 but Haws hit a jumper and Yoeli Childs converted a 3-point play for a 67-62 lead at the Waves never caught up. Tags: BYU Cougars Basketball/TJ Haws/WCC Associated Press Written by Haws, who also had seven rebounds, went 18 of 22 from the foul line, career bests for attempts and makes. Childs had 20 points, his fourth straight 20-plus game, 13th this season and 28th in his career. Freshman Gavin Baxter had a career high 13 points for the Cougars (12-8, 4-1 West Coast Conference), going 5 for 5 from the field and 3 of 3 from the line, and had six boards and three blocks.last_img read more

The HERO Sports FCS All-Preseason Team Features SUU; Weber State Players

first_img Tags: Adam Rodriguez/HERO Sports FCS All-Preseason Team/Jerry Rice/Josh Davis/Rashid Shaheed/Southern Utah Football/Trey Tuttle/Ty Whitworth/Weber State Football/Zach Larsen June 6, 2019 /Sports News – Local The HERO Sports FCS All-Preseason Team Features SUU; Weber State Players FacebookTwitterLinkedInEmailOGDEN, Utah-Thursday, the HERO Sports FCS All-Preseason team was announced, featuring representatives from both Weber State and Southern Utah’s football programs.SUU senior offensive lineman Zach Larsen was named to the first team, with five Wildcats being named to the second and third teams.Among the Weber State representatives are sophomore tailback Josh Davis (the reigning Jerry Rice Award winner, given to the top freshman in FCS football) junior return specialist Rashid Shaheed on the second team.Representing the Wildcats on the third team were junior offensive lineman Ty Whitworth, senior defensive lineman Adam Rodriguez and junior kicker Trey Tuttle. Written by Brad Jameslast_img read more