oce: an R package for Oceanographic Analysis

Kelley, Dan; Richards, Clark; Layton, Chantelle

doi:10.21105/joss.03594

Cited by 41 publications

(34 citation statements)

References 8 publications

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“…– Moon parameters (presence – when above the horizon –, altitude, illuminated fraction) were extracted with ‘oce' R package (Kelley et al 2020) using some outputs of the ‘moonAngle()' function.…”

Section: Methodsmentioning

confidence: 99%

“…Dawn was considered to begin when the sun is six degrees below the horizon and ends at sunrise time. Dusk begins at sunset time and ends when the sun is six degrees below the horizon.– Night duration was calculated for each location with the difference between sunset and sunrise time.– Moon parameters (presence – when above the horizon –, altitude, illuminated fraction) were extracted with ‘oce' R package (Kelley et al 2020) using some outputs of the ‘moonAngle()' function.…”

Section: Methodsmentioning

confidence: 99%

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Diel at‐sea activity of two species of great albatrosses: the ontogeny of foraging and movement behaviour

Pajot

Corbeau

Jambon³

et al. 2021

Journal of Avian Biology

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The first year of life is a period of high mortality in animals. Reduced foraging capacities of naive individuals might be the primary cause of their mortality. These capacities are supposed to be progressively acquired during the first months of life. In this study, we investigate the ontogeny of flight capacities, by day and night, of first‐year individuals, and compare it with adults from two closely related species of great albatrosses: Amsterdam Diomedea amsterdamensis and wandering Diomedea exulans albatrosses which forage in different environmental conditions. We used 71 tracks of 71 juvenile birds and 141 of 116 incubating adults to compare both age categories. In order to explore the effect of moon light on night activity, we elaborated a new formula which improves the precision of the proxy of moon illumination. By day, we found that juveniles of both species reach some adult foraging capacities in less than two months. By night, albatrosses have reduced activity increasing during the first weeks at sea for juveniles and changing in accordance with moon illumination for both juveniles and adults. A peak of flight activity at dawn and dusk was apparent for both species. Interspecific comparison underlined that Amsterdam albatrosses were more active than wandering albatrosses, suggesting a difference in food and foraging strategy. Overall, we highlighted how life history traits, environmental conditions and time of the day affect the foraging activity of two related species of seabirds.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Diel at‐sea activity of two species of great albatrosses: the ontogeny of foraging and movement behaviour

Pajot

Corbeau

Jambon³

et al. 2021

Journal of Avian Biology

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show abstract

“…Next, we annotated this telemetry data with the following covariates: bear age and cub status from when the bears were tagged; ordinal date and hour of the GPS fix; sun altitude calculated using the R package (Kelley et al, 2022); wind velocity, snow depth, total precipitation, surface solar radiation from the ERA5 meteorological reanalysis project (Hersbach et al, 2020); sea ice concentration (Comiso, 2017); bathymetry (IOC et al, 2003); tidal currents (St-Laurent et al, 2008); and sea ice motion vectors by the National Snow and Ice Data Center (NSIDC; Tschudi et al, 2019, 2020). Spatial covariates provided as a gridded raster were interpolated in space and time as in Togunov et al (2017, 2018).…”

Section: Methodsmentioning

confidence: 99%

Drivers of polar bear behavior, and the possible effects of prey availability on foraging strategy

Togunov

Derocher

Lunn

et al. 2022

Preprint

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Change in behavior is one of the earliest measurable responses to variation in habitat suitability, making the study of factors that promote behaviors particularly important in areas undergoing environmental change. We applied hidden Markov models to remote movement data of 14 polar bears, Ursus maritimus, from Western Hudson Bay, Canada between 2011 and 2021 during the foraging season (January--June) when bears inhabit the sea ice. The model incorporated bear movement and orientation relative to wind to classify three behaviors (stationary/drifting, area-restricted search, and olfactory search), and investigated 11 factors to identify conditions that may promote these behaviors. In contrast to other polar bear populations, we found high levels of evening activity, with active behaviors peaking around 20:00. We identified an increase in activity as the ice-covered season progressed. This apparent shift in foraging strategy from still-hunting to active search corresponds to a shift in prey availability (i.e., increase in haul-out behavior from early winter to the spring pupping and molting seasons). Last, we described spatial patterns of distribution with respect to season and ice concentration that may be indicative of variation in habitat quality and segregation by bear age that may reflect competitive exclusion. Our observations were generally consistent with predictions of the marginal value theorem, and differences between our findings compared to other populations could be explained by variation in regional or temporal variation in resource abundance or distribution. Our findings and methodology can help identify periods, locations, and environmental conditions associated with habitat quality and can improve our understanding polar bear behavioral ecology and aid conservation.

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“…The HadCRUT5 data set can be found at https://www.metoffice.gov.uk/ hadobs/hadcrut5/. All maps were obtained by using the oce R-package 128 .…”

Section: Data Availabilitymentioning

confidence: 99%

Advancing research on compound weather and climate events via large ensemble model simulations

et al. 2023

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Societally relevant weather impacts typically result from compound events, which are rare combinations of weather and climate drivers. Focussing on four event types arising from different combinations of climate variables across space and time, here we illustrate that robust analyses of compound events — such as frequency and uncertainty analysis under present-day and future conditions, event attribution to climate change, and exploration of low-probability-high-impact events — require data with very large sample size. In particular, the required sample is much larger than that needed for analyses of univariate extremes. We demonstrate that Single Model Initial-condition Large Ensemble (SMILE) simulations from multiple climate models, which provide hundreds to thousands of years of weather conditions, are crucial for advancing our assessments of compound events and constructing robust model projections. Combining SMILEs with an improved physical understanding of compound events will ultimately provide practitioners and stakeholders with the best available information on climate risks.

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oce: an R package for Oceanographic Analysis

Cited by 41 publications

References 8 publications

Diel at‐sea activity of two species of great albatrosses: the ontogeny of foraging and movement behaviour

Diel at‐sea activity of two species of great albatrosses: the ontogeny of foraging and movement behaviour

Drivers of polar bear behavior, and the possible effects of prey availability on foraging strategy

Advancing research on compound weather and climate events via large ensemble model simulations

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