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  • 1
    Online Resource
    Online Resource
    Predicting subsurface sonar observations with satellite-derived ocean surface data in the California Current Ecosystem
    Public Library of Science (PLoS) ; 2021
    In:  PLOS ONE Vol. 16, No. 8 ( 2021-8-20), p. e0248297-
    Details
    In: PLOS ONE, Public Library of Science (PLoS), Vol. 16, No. 8 ( 2021-8-20), p. e0248297-
    Abstract: Vessel-based sonar systems that focus on the water column provide valuable information on the distribution of underwater marine organisms, but such data are expensive to collect and limited in their spatiotemporal coverage. Satellite data, however, are widely available across large regions and provide information on surface ocean conditions. If satellite data can be linked to subsurface sonar measurements, it may be possible to predict marine life over broader spatial regions with higher frequency using satellite observations. Here, we use random forest models to evaluate the potential for predicting a sonar-derived proxy for subsurface biomass as a function of satellite imagery in the California Current Ecosystem. We find that satellite data may be useful for prediction under some circumstances, but across a range of sonar frequencies and depths, overall model performance was low. Performance in spatial interpolation tasks exceeded performance in spatial and temporal extrapolation, suggesting that this approach is not yet reliable for forecasting or spatial extrapolation. We conclude with some potential limitations and extensions of this work.
    Type of Medium: Online Resource
    ISSN: 1932-6203
    URL: Article
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    DOI: 10.1371/journal.pone.0248297
    DOI: 10.1371/journal.pone.0248297.g001
    DOI: 10.1371/journal.pone.0248297.g002
    DOI: 10.1371/journal.pone.0248297.g003
    DOI: 10.1371/journal.pone.0248297.g004
    DOI: 10.1371/journal.pone.0248297.t001
    DOI: 10.1371/journal.pone.0248297.s001
    DOI: 10.1371/journal.pone.0248297.s002
    DOI: 10.1371/journal.pone.0248297.r001
    DOI: 10.1371/journal.pone.0248297.r002
    DOI: 10.1371/journal.pone.0248297.r003
    DOI: 10.1371/journal.pone.0248297.r004
    DOI: 10.1371/journal.pone.0248297.r005
    DOI: 10.1371/journal.pone.0248297.r006
    Language: English
    Publisher: Public Library of Science (PLoS)
    Publication Date: 2021
    detail.hit.zdb_id: 2267670-3
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  • 2
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    Online Resource
    Tropical Pacific Influence on the Source and Transport of Marine Aerosols to West Antarctica*
    American Meteorological Society ; 2014
    In:  Journal of Climate Vol. 27, No. 3 ( 2014-02-01), p. 1343-1363
    Details
    In: Journal of Climate, American Meteorological Society, Vol. 27, No. 3 ( 2014-02-01), p. 1343-1363
    Abstract: The climate of West Antarctica is strongly influenced by remote forcing from the tropical Pacific. For example, recent surface warming over West Antarctica reflects atmospheric circulation changes over the Amundsen Sea, driven by an atmospheric Rossby wave response to tropical sea surface temperature (SST) anomalies. Here, it is demonstrated that tropical Pacific SST anomalies also influence the source and transport of marine-derived aerosols to the West Antarctic Ice Sheet. Using records from four firn cores collected along the Amundsen coast of West Antarctica, the relationship between sea ice–modulated chemical species and large-scale atmospheric variability in the tropical Pacific from 1979 to 2010 is investigated. Significant correlations are found between marine biogenic aerosols and sea salts, and SST and sea level pressure in the tropical Pacific. In particular, La Niña–like conditions generate an atmospheric Rossby wave response that influences atmospheric circulation over Pine Island Bay. Seasonal regression of atmospheric fields on methanesulfonic acid (MSA) reveals a reduction in onshore wind velocities in summer at Pine Island Bay, consistent with enhanced katabatic flow, polynya opening, and coastal dimethyl sulfide production. Seasonal regression of atmospheric fields on chloride (Cl−) reveals an intensification in onshore wind velocities in winter, consistent with sea salt transport from offshore source regions. Both the source and transport of marine aerosols to West Antarctica are found to be modulated by similar atmospheric dynamics in response to remote forcing. Finally, the regional ice-core array suggests that there is both a temporally and a spatially varying response to remote tropical forcing.
    Type of Medium: Online Resource
    ISSN: 0894-8755 , 1520-0442
    URL: Article
    URL: Article
    DOI: 10.1175/JCLI-D-13-00148.1
    DOI: 10.1175/JCLI-D-13-00148.s1
    RVK:
    UA 4548
    Language: English
    Publisher: American Meteorological Society
    Publication Date: 2014
    detail.hit.zdb_id: 246750-1
    detail.hit.zdb_id: 2021723-7
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  • 3
    Online Resource
    Online Resource
    Divergent trajectories of Antarctic surface melt under two twenty-first-century climate scenarios
    Springer Science and Business Media LLC ; 2015
    In:  Nature Geoscience Vol. 8, No. 12 ( 2015-12), p. 927-932
    Details
    In: Nature Geoscience, Springer Science and Business Media LLC, Vol. 8, No. 12 ( 2015-12), p. 927-932
    Type of Medium: Online Resource
    ISSN: 1752-0894 , 1752-0908
    URL: Article
    DOI: 10.1038/ngeo2563
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2015
    detail.hit.zdb_id: 2396648-8
    detail.hit.zdb_id: 2405323-5
    SSG: 16,13
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  • 4
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    The role of in‐situ ocean data assimilation in ECMWF subseasonal forecasts of SST and MLD over the tropical Pacific Ocean
    Wiley ; 2023
    In:  Quarterly Journal of the Royal Meteorological Society
    Details
    In: Quarterly Journal of the Royal Meteorological Society, Wiley
    Abstract: The tropical Pacific plays an important role in modulating the global climate through its prevailing sea surface temperature spatial structure and dominant climate modes like ENSO, MJO, and their teleconnections. These modes of variability, including their oceanic anomalies, are considered to provide sources of prediction skill on subseasonal timescales in the tropics. Therefore, this study aims to examine how assimilating in‐situ ocean observations influences the initial ocean sea surface temperature (SST) and mixed layer depth (MLD) and their subseasonal forecasts. We analyze two subseasonal forecast systems generated with European Centre for Medium‐Range Weather Forecasts (ECMWF) Integrated Forecast System (IFS) where the ocean states were initialized using two Observing System Experiment (OSE) reanalyses. We find that the SST differences between forecasts with and without ocean data assimilation grow with time, resulting in a reduced cold tongue bias when assimilating ocean observations. Two mechanisms related to air‐sea coupling are considered to contribute to this growth of SST differences. One is a positive feedback between zonal SST gradient, pressure gradient, and surface wind. The other is the difference in Ekman suction and mixing at the equator due to surface wind speed differences. While the initial mixed layer depth (MLD) can be improved through ocean data assimilation, this improvement is not maintained in the forecasts. Instead, the MLD in both experiments rapidly shoals at the beginning of the forecast. These results emphasize how initialization and model biases influence the air‐sea interaction and the accuracy of subseasonal forecast in the tropical Pacific. This article is protected by copyright. All rights reserved.
    Type of Medium: Online Resource
    ISSN: 0035-9009 , 1477-870X
    URL: Article
    DOI: 10.1002/qj.4570
    RVK:
    UA 1000
    RVK:
    UA 7650
    Language: English
    Publisher: Wiley
    Publication Date: 2023
    detail.hit.zdb_id: 3142-2
    detail.hit.zdb_id: 2089168-4
    SSG: 14
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  • 5
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    Online Resource
    Observational evidence of the downstream impact on tropical rainfall from stratospheric Kelvin waves
    Springer Science and Business Media LLC ; 2018
    In:  Climate Dynamics Vol. 50, No. 9-10 ( 2018-5), p. 3775-3782
    Details
    In: Climate Dynamics, Springer Science and Business Media LLC, Vol. 50, No. 9-10 ( 2018-5), p. 3775-3782
    Type of Medium: Online Resource
    ISSN: 0930-7575 , 1432-0894
    URL: Article
    DOI: 10.1007/s00382-017-3844-1
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2018
    detail.hit.zdb_id: 382992-3
    detail.hit.zdb_id: 1471747-5
    SSG: 16,13
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  • 6
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    Are Long-Term Changes in Mixed Layer Depth Influencing North Pacific Marine Heatwaves?
    American Meteorological Society ; 2021
    In:  Bulletin of the American Meteorological Society Vol. 102, No. 1 ( 2021-01), p. S59-S66
    Details
    In: Bulletin of the American Meteorological Society, American Meteorological Society, Vol. 102, No. 1 ( 2021-01), p. S59-S66
    Type of Medium: Online Resource
    ISSN: 0003-0007 , 1520-0477
    URL: Article
    DOI: 10.1175/BAMS-D-20-0144.1
    Language: Unknown
    Publisher: American Meteorological Society
    Publication Date: 2021
    detail.hit.zdb_id: 2029396-3
    detail.hit.zdb_id: 419957-1
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  • 7
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    North Atlantic salinity as a predictor of Sahel rainfall
    American Association for the Advancement of Science (AAAS) ; 2016
    In:  Science Advances Vol. 2, No. 5 ( 2016-05-06)
    Details
    In: Science Advances, American Association for the Advancement of Science (AAAS), Vol. 2, No. 5 ( 2016-05-06)
    Abstract: Water evaporating from the ocean sustains precipitation on land. This ocean-to-land moisture transport leaves an imprint on sea surface salinity (SSS). Thus, the question arises of whether variations in SSS can provide insight into terrestrial precipitation. This study provides evidence that springtime SSS in the subtropical North Atlantic ocean can be used as a predictor of terrestrial precipitation during the subsequent summer monsoon in Africa. Specifically, increased springtime SSS in the central to eastern subtropical North Atlantic tends to be followed by above-normal monsoon-season precipitation in the African Sahel. In the spring, high SSS is associated with enhanced moisture flux divergence from the subtropical oceans, which converges over the African Sahel and helps to elevate local soil moisture content. From spring to the summer monsoon season, the initial water cycling signal is preserved, amplified, and manifested in excessive precipitation. According to our analysis of currently available soil moisture data sets, this 3-month delay is attributable to a positive coupling between soil moisture, moisture flux convergence, and precipitation in the Sahel. Because of the physical connection between salinity, ocean-to-land moisture transport, and local soil moisture feedback, seasonal forecasts of Sahel precipitation can be improved by incorporating SSS into prediction models. Thus, expanded monitoring of ocean salinity should contribute to more skillful predictions of precipitation in vulnerable subtropical regions, such as the Sahel.
    Type of Medium: Online Resource
    ISSN: 2375-2548
    URL: Article
    DOI: 10.1126/sciadv.1501588
    Language: English
    Publisher: American Association for the Advancement of Science (AAAS)
    Publication Date: 2016
    detail.hit.zdb_id: 2810933-8
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  • 8
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    Observed Strengthening of the Zonal Sea Surface Temperature Gradient across the Equatorial Pacific Ocean*
    American Meteorological Society ; 2009
    In:  Journal of Climate Vol. 22, No. 16 ( 2009-08-15), p. 4316-4321
    Details
    In: Journal of Climate, American Meteorological Society, Vol. 22, No. 16 ( 2009-08-15), p. 4316-4321
    Abstract: Decadal variations of very small amplitude [∼0.3°C in sea surface temperature (SST)] in the tropical Pacific Ocean, the genesis region of the interannual El Niño–Southern Oscillation (ENSO) phenomenon, have been shown to have powerful impacts on global climate. Future projections from different climate models do not agree on how this critical feature will change under the influence of anthropogenic forcing. A number of attempts have been made to resolve this issue by examining observed trends from the 1880s to the present, a period of rising atmospheric concentrations of greenhouse gases. A recent attempt concluded that the three major datasets disagreed on the trend in the equatorial gradient of SST. Using a corrected version of one of these datasets, and extending the analysis to the seasonal cycle, it is shown here that all agree that the equatorial Pacific zonal SST gradient has strengthened from 1880 to 2005 during the boreal fall when this gradient is normally strongest. This result appears to favor a theory for future changes based on ocean dynamics over one based on atmospheric energy considerations. Both theories incorporate the expectation, based on ENSO theory, that the zonal sea level pressure (SLP) gradient in the tropical Pacific is coupled to SST and should therefore strengthen along with the SST gradient. While the SLP gradient has not strengthened, it is found that it appears to have weakened only during boreal spring, consistent with the SST seasonal trends. Most of the coupled models included in the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report underestimate the strengthening SST gradient in boreal fall, and show almost no change in the SLP gradient in any season. The observational analyses herein suggest that both theories are at work but with relative strengths that vary seasonally, and that the two theories need not be inconsistent with each other.
    Type of Medium: Online Resource
    ISSN: 1520-0442 , 0894-8755
    URL: Article
    DOI: 10.1175/2009JCLI2936.1
    RVK:
    UA 4548
    Language: English
    Publisher: American Meteorological Society
    Publication Date: 2009
    detail.hit.zdb_id: 246750-1
    detail.hit.zdb_id: 2021723-7
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  • 9
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    Influence of the Atlantic Meridional Overturning Circulation on the Northern Hemisphere Surface Temperature Response to Radiative Forcing
    American Meteorological Society ; 2018
    In:  Journal of Climate Vol. 31, No. 22 ( 2018-11-15), p. 9207-9224
    Details
    In: Journal of Climate, American Meteorological Society, Vol. 31, No. 22 ( 2018-11-15), p. 9207-9224
    Abstract: Many modeling studies have shown that the Atlantic meridional overturning circulation (AMOC) will weaken under increased greenhouse gas forcing, but the influence of AMOC internal variability on climate change in the context of a large initial condition ensemble has received less attention. Here, the Community Earth System Model Large Ensemble (CESM LE) is used to separate the AMOC-forced response from AMOC internal variability, and then assess their joint influence on surface warming. Similar to other models, the CESM LE projects a weakening AMOC in response to increased greenhouse gas forcing caused by freshening and decreased buoyancy fluxes in the North Atlantic. Yet if this forced response is removed using the ensemble mean, there is a positive relationship between global surface warming and AMOC strength. In other words, when the AMOC strengthens relative to the ensemble mean (i.e., weakens less), global surface warming increases relative to the ensemble mean response. This unforced surface warming occurs in northern Eurasia and in the Nordic and Barents Seas near the sea ice edge. Comparison of CESM simulations with and without a dynamic ocean shows that the unforced surface warming in the Nordic and Barents Seas results from both ocean and atmospheric circulation variability. In contrast, this comparison suggests that AMOC-associated Eurasian warming results from atmospheric circulation variability alone. In sum, the AMOC-forced response and AMOC internal variability have distinct relationships with surface temperature. Forced AMOC weakening decreases with surface warming, while unforced AMOC strengthening leads to surface warming.
    Type of Medium: Online Resource
    ISSN: 0894-8755 , 1520-0442
    URL: Article
    DOI: 10.1175/JCLI-D-17-0900.1
    RVK:
    UA 4548
    Language: Unknown
    Publisher: American Meteorological Society
    Publication Date: 2018
    detail.hit.zdb_id: 246750-1
    detail.hit.zdb_id: 2021723-7
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  • 10
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    Online Resource
    The Effect of the Galápagos Islands on ENSO in Forced Ocean and Hybrid Coupled Models
    American Meteorological Society ; 2008
    In:  Journal of Physical Oceanography Vol. 38, No. 11 ( 2008-11-01), p. 2519-2534
    Details
    In: Journal of Physical Oceanography, American Meteorological Society, Vol. 38, No. 11 ( 2008-11-01), p. 2519-2534
    Abstract: An ocean general circulation model (OGCM) of the tropical Pacific Ocean is used to examine the effects of the Galápagos Islands on the El Niño–Southern Oscillation (ENSO). First, a series of experiments is conducted using the OGCM in a forced context, whereby an idealized El Niño event may be examined in cases with and without the Galápagos Islands. In this setup, the sensitivity of the sea surface temperature (SST) anomaly response to the presence of the Galápagos Islands is examined. Second, with the OGCM coupled to the atmosphere via zonal wind stress, experiments are conducted with and without the Galápagos Islands to determine how the Galápagos Islands influence the time scale of ENSO. In the forced setup, the Galápagos Islands lead to a damped SST anomaly given an identical zonal wind stress perturbation. Mixed layer heat budget calculations implicate the entrainment mixing term, which confirms that the difference is due to the Galápagos Islands changing the background mean state, that is, the equatorial thermocline as diagnosed in a previous paper. In the hybrid coupled experiments, there is a clear shift in the power spectrum of SST anomalies in the eastern equatorial Pacific. Specifically, the Galápagos Islands lead to a shift in the ENSO time scale from a biennial to a quasi-quadrennial period. Mechanisms for the shift in ENSO time scale due to the Galápagos Islands are discussed in the context of well-known paradigms for the oscillatory nature of ENSO.
    Type of Medium: Online Resource
    ISSN: 1520-0485 , 0022-3670
    URL: Article
    DOI: 10.1175/2008JPO3848.1
    Language: English
    Publisher: American Meteorological Society
    Publication Date: 2008
    detail.hit.zdb_id: 2042184-9
    detail.hit.zdb_id: 184162-2
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