Franklin Schwing | National Oceanographic Data Center (original) (raw)
Papers by Franklin Schwing
Progress in Oceanography, 2011
The study of climate impacts on Living Marine Resources (LMRs) has increased rapidly in recent ye... more The study of climate impacts on Living Marine Resources (LMRs) has increased rapidly in recent years with the availability of climate model simulations contributed to the assessment reports of the Intergovernmental Panel on Climate Change (IPCC). Collaboration between climate and LMR scientists and shared understanding of critical challenges for such applications are essential for developing robust projections of climate impacts on LMRs. This paper assesses present approaches for generating projections of climate impacts on LMRs using IPCC-class climate models, recommends practices that should be followed for these applications, and identifies priority developments that could improve current projections. Understanding of the climate system and its representation within climate models has progressed to a point where many climate model outputs can now be used effectively to make LMR projections. However, uncertainty in climate model projections (particularly biases and inter-model spread at regional to local scales), coarse climate model resolution, and the uncertainty and potential complexity of the mechanisms underlying the response of LMRs to climate limit the robustness and precision of LMR projections. A variety of techniques including the analysis of multi-model ensembles, bias corrections, and statistical and dynamical downscaling can ameliorate some limitations, though the assumptions underlying these approaches and the sensitivity of results to their application must be assessed for each application. Developments in LMR science that could improve current projections of climate impacts on LMRs include improved understanding of the multi-scale mechanisms that link climate and LMRs and better representations of these mechanisms within more holistic LMR models. These developments require a strong baseline of field and laboratory observations including long time series and measurements over the broad range of spatial and temporal scales over which LMRs and climate interact. Priority developments for 0079-6611/$ -see front matter Published by Elsevier Ltd.
This report summarizes the recent state of the California Current System (CCS), primarily during ... more This report summarizes the recent state of the California Current System (CCS), primarily during the period April 2005 through early 2006, and includes observations of ocean conditions made from Washington State south to Baja California. During 2005, the CCS experienced very unusual "ocean weather." For example, off Washington, Oregon and northern California, the start of upwelling was delayed, resulting in anomalously warm sea surface temperatures through the spring and the early summer months. The warming observed in the northern California Current (NCC) in the spring and early summer appeared to be a regional phenomenon, since waters south of approximately 35˚N to the California-Mexico border were near the long-term average, and cooler-than-normal temperatures prevailed off Baja California. The extent of the warming and subsequent ecosystem response was similar to that of a major tropical El Niño event. However, we know from observations made at the equator that equatorial waters were in an El Niño-neutral state. The impacts on the NCC pelagic ecosystem were profound with very low biomass of zooplankton observed in Monterey Bay, the Gulf of the Farallones, and off Oregon, accompanied by unprecedented reproductive failure and mortality in sev-eral locally-breeding seabird species. Recruitment failure was seen in a variety of fishes as well. The proximate cause was a delay in the initiation of the upwelling season in the NCC (which usually begins in April) to a nearly unprecedented start time of late July. Thus, animals that reproduce in spring and in other years would find bountiful food resources, found themselves faced with famine rather than feast. Similarly, marine mammals and birds which migrate to the NCC upwelling region in spring and summer, which would otherwise find a high biomass of energetically-rich zooplankton and small pelagic fish upon which to feed, were equally disappointed. Moreover, 2005 marked the third year of chronically warm conditions in the NCC, a situation which could have led to a general reduction in physiological condition of fish and birds, rendering them less tolerant of adverse ocean conditions in 2005.
Fisheries Oceanography, 2007
Declines of Steller sea lion (Eumetopias jubatus) populations in the Aleutian Islands and Gulf of... more Declines of Steller sea lion (Eumetopias jubatus) populations in the Aleutian Islands and Gulf of Alaska could be a consequence of physical oceanographic changes associated with the 1976-77 climate regime shift. Changes in ocean climate are hypothesized to have affected the quantity, quality, and accessibility of prey, which in turn may have affected the rates of birth and death of sea lions. Recent studies of the spatial and temporal variations in the ocean climate system of the North Pacific support this hypothesis. Ocean climate changes appear to have created adaptive opportunities for various species that are preyed upon by Steller sea lions at mid-trophic levels. The east-west asymmetry of the oceanic response to climate forcing after 1976-77 is consistent with both the temporal aspect (populations decreased after the late 1970s) and the spatial aspect of the decline (western, but not eastern, sea lion populations decreased). These broad-scale climate variations appear to be modulated by regionally sensitive biogeographic structures along the Aleutian Islands and Gulf of Alaska, which include a transition point from coastal to open-ocean conditions at Samalga Pass westward along the Aleutian Islands. These transition points delineate distinct clusterings of different combinations of prey species, which are in turn correlated with differential population sizes and trajectories of Steller sea lions. Archaeological records spanning 4000 yr further indicate that sea lion populations have experienced major shifts in abundance in the past. Shifts in ocean climate are the most parsimonious underlying explanation for the broad suite of ecosystem changes that have been observed in the North Pacific Ocean in recent decades.
Declines of Steller sea lion (Eumetopias jubatus) populations in the Aleutian Islands and Gulf of... more Declines of Steller sea lion (Eumetopias jubatus) populations in the Aleutian Islands and Gulf of Alaska could be a consequence of physical oceanographic changes associated with the 1976-77 climate regime shift. Changes in ocean climate are hypothesized to have affected the quantity, quality and accessibility of prey, which in turn may have affected the rates of birth and death of sea lions. Recent studies of the spatial and temporal variations in the ocean climate system of the North Pacific support this hypothesis. Ocean climate changes appear to have created adaptive opportunities for various species that are preyed upon by Steller sea lions at mid-trophic levels. The eastwest asymmetry of the oceanic response to climate forcing after 1976-77 is consistent with both the temporal aspect (populations decreased after the late 1970's) and the spatial aspect of the decline (western, but not eastern, sea lion populations decreased). These broad-scale climate variations appear to be modulated by regionally sensitive biogeographic structures along the Aleutian Islands and Gulf of Alaska, which include a transition point from coastal to open-ocean conditions at Samalga Pass westward along the Aleutian Islands. These transition points delineate distinct clusterings of different combinations of prey species, which are in turn correlated with differential population sizes and trajectories of Steller sea lions. Archaeological records spanning 4000 years further indicate that sea lion populations have experienced major shifts in abundance in the past. Shifts in ocean climate are the most parsimonious underlying explanation for the broad suite of ecosystem changes that have been observed in the North Pacific Ocean in recent decades.
Declines of Steller sea lion (Eumetopias jubatus) populations in the Aleutian Islands and Gulf of... more Declines of Steller sea lion (Eumetopias jubatus) populations in the Aleutian Islands and Gulf of Alaska could be a consequence of physical oceanographic changes associated with the 1976-77 climate regime shift. Changes in ocean climate are hypothesized to have affected the quantity, quality, and accessibility of prey, which in turn may have affected the rates of birth and death of sea lions. Recent studies of the spatial and temporal variations in the ocean climate system of the North Pacific support this hypothesis. Ocean climate changes appear to have created adaptive opportunities for various species that are preyed upon by Steller sea lions at mid-trophic levels. The east-west asymmetry of the oceanic response to climate forcing after 1976-77 is consistent with both the temporal aspect (populations decreased after the late 1970s) and the spatial aspect of the decline (western, but not eastern, sea lion populations decreased). These broad-scale climate variations appear to be modulated by regionally sensitive biogeographic structures along the Aleutian Islands and Gulf of Alaska, which include a transition point from coastal to open-ocean conditions at Samalga Pass westward along the Aleutian Islands. These transition points delineate distinct clusterings of different combinations of prey species, which are in turn correlated with differential population sizes and trajectories of Steller sea lions. Archaeological records spanning 4000 yr further indicate that sea lion populations have experienced major shifts in abundance in the past. Shifts in ocean climate are the most parsimonious underlying explanation for the broad suite of ecosystem changes that have been observed in the North Pacific Ocean in recent decades.
Marine Geology, 2002
From August 1993 to August 1994, six moorings that measure current, temperature, salinity, and wa... more From August 1993 to August 1994, six moorings that measure current, temperature, salinity, and water clarity were deployed along the axis of Monterey Canyon to study the circulation and transport of water and suspended particulate matter through the canyon system. The moorings occupied three sites that are morphologically different: a narrow transverse section (axis width 900 m) at 1450 m water depth, a wide transverse section at 2837 m, and a third site in the fan valley axis farther offshore at 3223 m that recorded for 3 yr. In addition, CTD/transmissometer casts were conducted within and near the Monterey Canyon during four cruises. Our data show a mainly biogenic, surface turbid layer, a limited intermediate nepheloid layer, and a bottom nepheloid layer. There is a consistent presence of a turbid layer within the canyon at a water depth of about 1500 m. Tidal flow dominates at all sites, but currents above the canyon rim and within the canyon appear to belong to two distinct dynamic systems. Bottom intensification of currents plays an important role in raising the near-bottom shear stress high enough that bottom sediments are often, if not always, resuspended. Mean flow pattern suggests a convergence zone between the narrow and wide site: the near-bed (100 m above bottom where the lowest current meter was located) mean transport is down-canyon at the 1450-m site, while the near-bottom transport at the 2837-m site is up-canyon, at a smaller magnitude. Transport at the 3223-m site is dominantly NNW, cross-canyon, with periods of up-canyon flow over 3 yr. A very high-turbidity event was recorded 100 m above the canyon bottom at the narrow site. The event started very abruptly and lasted more than a week. This event was not detected at either of the deeper sites. A canyon head flushing event is likely the cause. ß
Eos, Transactions American Geophysical Union, 2004
Fisheries Oceanography, 2006
Both low-and high-resolution studies of wind and upwelling were conducted off the west coasts of ... more Both low-and high-resolution studies of wind and upwelling were conducted off the west coasts of North and South America between August 1999 and December 2001. For the low-resolution study, done at 25 regional sites spanning both coasts, weekly mean winds were calculated from satellite measurements, from geostrophic estimates, and from an operational 100-km-resolution global atmospheric model. The satellite-measured winds, used as the reference, showed that the coastal regions of both North and South America were divided into fairly uniform climatic domains located at higher, mid, and lower latitudes. All three weekly-mean wind data sets were compared at each of the 25 sites, and then used to estimate upwelling based on the method employed by NOAA's Pacific Fisheries Environmental Laboratory. Within each of the wind domains, model-derived wind and upwelling estimates agreed with satellite-derived values better than those from geostrophic-derived estimates. To investigate variability between the regional sites, a 9-km-resolution atmospheric model was run for an area off California which spanned four of the regional sites. This high-resolution model, verified with satellite measurements, revealed jets of wind curving and intensifying around coastal promontories. These near-shore wind jets, undetected in the global model, resulted in strong upwelling bands on the order of 50 km alongshore by 20 km offshore. These bands are critical for calculating local upwelling. Our results indicate that regional upwelling estimates for fisheries research can be improved by replacing geostrophic estimates of winds with those from a global atmospheric model. For localized coastal upwelling estimates, however, models with resolution an order of magnitude higher are required.
J Phys Oceanogr, 1992
A linear, barotropic numerical model that features realistic bathymetry of the Scotian Shelf prov... more A linear, barotropic numerical model that features realistic bathymetry of the Scotian Shelf provides solutions forced by steady and periodic wind stress that are generally incoherent on spatial scales of the shelf width. Closed circulation cells occur in d a t i o n with, and on the scales of, major bathymetric features. Bathymetrically steered now is prevalenf and more evident at lower frequencies. Model transport forced by a coastally trapped wave propagating across the backward boundary is not sensitive to the modal structure of the incident wave; bathymetry rapidly modifies the wave form as it propagates in the free diredon. Higher modes and reflected waves are probably dissipated over short distances by scattering and strong bottom stress. Patterns seen in the model solutions are consistent with resulu from more fundamental models, and are readily explained by relatively simple vorticity balances.
suggests that ENSO events are now starting from a higher level, leading to a stronger El Niño (we... more suggests that ENSO events are now starting from a higher level, leading to a stronger El Niño (weaker La Niña) signal in the atmosphere and ocean.
Oceanography, Dec 1, 2013
This report is a summary and preliminary analysis of recent observations of oceanographc and biol... more This report is a summary and preliminary analysis of recent observations of oceanographc and biological struc- ture of the California Current region, with emphasis on atmospheric pressure and wind fields, ocean circulation pattern and hydrographic structure, and upper-ocean plankton distributions. There was a strong transition in atmospheric circulation and sea-surface temperature be- tween the fall of 1994 and wintedspring 1995.
... NEWELL GARFIELD, DAN E. TRACY Department of Oceanography Naval Postgraduate School Monterey, ... more ... NEWELL GARFIELD, DAN E. TRACY Department of Oceanography Naval Postgraduate School Monterey, California 93943 ... Data Buoy Center (NDBC) moored buoys - 46013 (Bodega Bay: 38.2"N, 123.3"W); 46026 (Farallones: 37.8"N, 122.7"W); 46012 (Half Moon Bay: 37.4"N ...
Investigaciones Marinas, 2002
Geophys Res Lett, 2005
State-space models were applied to several climate indices associated with the El Niño-Southern O... more State-space models were applied to several climate indices associated with the El Niño-Southern Oscillation (ENSO), including the Southern Oscillation Index (SOI) and its component sea level pressure series; the NINO3 sea surface temperature index; and the Northern Oscillation Index (NOI). The best models for each series include a significant long-term nonparametric trend combined with a stochastic stationary cyclic term that clearly delineates the El Niño and La Niña events. There is no evidence that the frequency of ENSO events has changed over the 20th century. The long-term trend, however, has contributed to an apparent increase in the magnitude of recent El Niño events. This trend, potentially related to global warming, has increased the level of each series by an amount equal to 30-50% of the amplitude of their corresponding annual cycle or cyclic ENSO term. Thus, the background sea surface temperature in the eastern equatorial Pacific is more than 0.5°C warmer now than prior to 1950, implying a greater overall impact of El Niño events.
Progress in Oceanography, 2011
The study of climate impacts on Living Marine Resources (LMRs) has increased rapidly in recent ye... more The study of climate impacts on Living Marine Resources (LMRs) has increased rapidly in recent years with the availability of climate model simulations contributed to the assessment reports of the Intergovernmental Panel on Climate Change (IPCC). Collaboration between climate and LMR scientists and shared understanding of critical challenges for such applications are essential for developing robust projections of climate impacts on LMRs. This paper assesses present approaches for generating projections of climate impacts on LMRs using IPCC-class climate models, recommends practices that should be followed for these applications, and identifies priority developments that could improve current projections. Understanding of the climate system and its representation within climate models has progressed to a point where many climate model outputs can now be used effectively to make LMR projections. However, uncertainty in climate model projections (particularly biases and inter-model spread at regional to local scales), coarse climate model resolution, and the uncertainty and potential complexity of the mechanisms underlying the response of LMRs to climate limit the robustness and precision of LMR projections. A variety of techniques including the analysis of multi-model ensembles, bias corrections, and statistical and dynamical downscaling can ameliorate some limitations, though the assumptions underlying these approaches and the sensitivity of results to their application must be assessed for each application. Developments in LMR science that could improve current projections of climate impacts on LMRs include improved understanding of the multi-scale mechanisms that link climate and LMRs and better representations of these mechanisms within more holistic LMR models. These developments require a strong baseline of field and laboratory observations including long time series and measurements over the broad range of spatial and temporal scales over which LMRs and climate interact. Priority developments for 0079-6611/$ -see front matter Published by Elsevier Ltd.
This report summarizes the recent state of the California Current System (CCS), primarily during ... more This report summarizes the recent state of the California Current System (CCS), primarily during the period April 2005 through early 2006, and includes observations of ocean conditions made from Washington State south to Baja California. During 2005, the CCS experienced very unusual "ocean weather." For example, off Washington, Oregon and northern California, the start of upwelling was delayed, resulting in anomalously warm sea surface temperatures through the spring and the early summer months. The warming observed in the northern California Current (NCC) in the spring and early summer appeared to be a regional phenomenon, since waters south of approximately 35˚N to the California-Mexico border were near the long-term average, and cooler-than-normal temperatures prevailed off Baja California. The extent of the warming and subsequent ecosystem response was similar to that of a major tropical El Niño event. However, we know from observations made at the equator that equatorial waters were in an El Niño-neutral state. The impacts on the NCC pelagic ecosystem were profound with very low biomass of zooplankton observed in Monterey Bay, the Gulf of the Farallones, and off Oregon, accompanied by unprecedented reproductive failure and mortality in sev-eral locally-breeding seabird species. Recruitment failure was seen in a variety of fishes as well. The proximate cause was a delay in the initiation of the upwelling season in the NCC (which usually begins in April) to a nearly unprecedented start time of late July. Thus, animals that reproduce in spring and in other years would find bountiful food resources, found themselves faced with famine rather than feast. Similarly, marine mammals and birds which migrate to the NCC upwelling region in spring and summer, which would otherwise find a high biomass of energetically-rich zooplankton and small pelagic fish upon which to feed, were equally disappointed. Moreover, 2005 marked the third year of chronically warm conditions in the NCC, a situation which could have led to a general reduction in physiological condition of fish and birds, rendering them less tolerant of adverse ocean conditions in 2005.
Fisheries Oceanography, 2007
Declines of Steller sea lion (Eumetopias jubatus) populations in the Aleutian Islands and Gulf of... more Declines of Steller sea lion (Eumetopias jubatus) populations in the Aleutian Islands and Gulf of Alaska could be a consequence of physical oceanographic changes associated with the 1976-77 climate regime shift. Changes in ocean climate are hypothesized to have affected the quantity, quality, and accessibility of prey, which in turn may have affected the rates of birth and death of sea lions. Recent studies of the spatial and temporal variations in the ocean climate system of the North Pacific support this hypothesis. Ocean climate changes appear to have created adaptive opportunities for various species that are preyed upon by Steller sea lions at mid-trophic levels. The east-west asymmetry of the oceanic response to climate forcing after 1976-77 is consistent with both the temporal aspect (populations decreased after the late 1970s) and the spatial aspect of the decline (western, but not eastern, sea lion populations decreased). These broad-scale climate variations appear to be modulated by regionally sensitive biogeographic structures along the Aleutian Islands and Gulf of Alaska, which include a transition point from coastal to open-ocean conditions at Samalga Pass westward along the Aleutian Islands. These transition points delineate distinct clusterings of different combinations of prey species, which are in turn correlated with differential population sizes and trajectories of Steller sea lions. Archaeological records spanning 4000 yr further indicate that sea lion populations have experienced major shifts in abundance in the past. Shifts in ocean climate are the most parsimonious underlying explanation for the broad suite of ecosystem changes that have been observed in the North Pacific Ocean in recent decades.
Declines of Steller sea lion (Eumetopias jubatus) populations in the Aleutian Islands and Gulf of... more Declines of Steller sea lion (Eumetopias jubatus) populations in the Aleutian Islands and Gulf of Alaska could be a consequence of physical oceanographic changes associated with the 1976-77 climate regime shift. Changes in ocean climate are hypothesized to have affected the quantity, quality and accessibility of prey, which in turn may have affected the rates of birth and death of sea lions. Recent studies of the spatial and temporal variations in the ocean climate system of the North Pacific support this hypothesis. Ocean climate changes appear to have created adaptive opportunities for various species that are preyed upon by Steller sea lions at mid-trophic levels. The eastwest asymmetry of the oceanic response to climate forcing after 1976-77 is consistent with both the temporal aspect (populations decreased after the late 1970's) and the spatial aspect of the decline (western, but not eastern, sea lion populations decreased). These broad-scale climate variations appear to be modulated by regionally sensitive biogeographic structures along the Aleutian Islands and Gulf of Alaska, which include a transition point from coastal to open-ocean conditions at Samalga Pass westward along the Aleutian Islands. These transition points delineate distinct clusterings of different combinations of prey species, which are in turn correlated with differential population sizes and trajectories of Steller sea lions. Archaeological records spanning 4000 years further indicate that sea lion populations have experienced major shifts in abundance in the past. Shifts in ocean climate are the most parsimonious underlying explanation for the broad suite of ecosystem changes that have been observed in the North Pacific Ocean in recent decades.
Declines of Steller sea lion (Eumetopias jubatus) populations in the Aleutian Islands and Gulf of... more Declines of Steller sea lion (Eumetopias jubatus) populations in the Aleutian Islands and Gulf of Alaska could be a consequence of physical oceanographic changes associated with the 1976-77 climate regime shift. Changes in ocean climate are hypothesized to have affected the quantity, quality, and accessibility of prey, which in turn may have affected the rates of birth and death of sea lions. Recent studies of the spatial and temporal variations in the ocean climate system of the North Pacific support this hypothesis. Ocean climate changes appear to have created adaptive opportunities for various species that are preyed upon by Steller sea lions at mid-trophic levels. The east-west asymmetry of the oceanic response to climate forcing after 1976-77 is consistent with both the temporal aspect (populations decreased after the late 1970s) and the spatial aspect of the decline (western, but not eastern, sea lion populations decreased). These broad-scale climate variations appear to be modulated by regionally sensitive biogeographic structures along the Aleutian Islands and Gulf of Alaska, which include a transition point from coastal to open-ocean conditions at Samalga Pass westward along the Aleutian Islands. These transition points delineate distinct clusterings of different combinations of prey species, which are in turn correlated with differential population sizes and trajectories of Steller sea lions. Archaeological records spanning 4000 yr further indicate that sea lion populations have experienced major shifts in abundance in the past. Shifts in ocean climate are the most parsimonious underlying explanation for the broad suite of ecosystem changes that have been observed in the North Pacific Ocean in recent decades.
Marine Geology, 2002
From August 1993 to August 1994, six moorings that measure current, temperature, salinity, and wa... more From August 1993 to August 1994, six moorings that measure current, temperature, salinity, and water clarity were deployed along the axis of Monterey Canyon to study the circulation and transport of water and suspended particulate matter through the canyon system. The moorings occupied three sites that are morphologically different: a narrow transverse section (axis width 900 m) at 1450 m water depth, a wide transverse section at 2837 m, and a third site in the fan valley axis farther offshore at 3223 m that recorded for 3 yr. In addition, CTD/transmissometer casts were conducted within and near the Monterey Canyon during four cruises. Our data show a mainly biogenic, surface turbid layer, a limited intermediate nepheloid layer, and a bottom nepheloid layer. There is a consistent presence of a turbid layer within the canyon at a water depth of about 1500 m. Tidal flow dominates at all sites, but currents above the canyon rim and within the canyon appear to belong to two distinct dynamic systems. Bottom intensification of currents plays an important role in raising the near-bottom shear stress high enough that bottom sediments are often, if not always, resuspended. Mean flow pattern suggests a convergence zone between the narrow and wide site: the near-bed (100 m above bottom where the lowest current meter was located) mean transport is down-canyon at the 1450-m site, while the near-bottom transport at the 2837-m site is up-canyon, at a smaller magnitude. Transport at the 3223-m site is dominantly NNW, cross-canyon, with periods of up-canyon flow over 3 yr. A very high-turbidity event was recorded 100 m above the canyon bottom at the narrow site. The event started very abruptly and lasted more than a week. This event was not detected at either of the deeper sites. A canyon head flushing event is likely the cause. ß
Eos, Transactions American Geophysical Union, 2004
Fisheries Oceanography, 2006
Both low-and high-resolution studies of wind and upwelling were conducted off the west coasts of ... more Both low-and high-resolution studies of wind and upwelling were conducted off the west coasts of North and South America between August 1999 and December 2001. For the low-resolution study, done at 25 regional sites spanning both coasts, weekly mean winds were calculated from satellite measurements, from geostrophic estimates, and from an operational 100-km-resolution global atmospheric model. The satellite-measured winds, used as the reference, showed that the coastal regions of both North and South America were divided into fairly uniform climatic domains located at higher, mid, and lower latitudes. All three weekly-mean wind data sets were compared at each of the 25 sites, and then used to estimate upwelling based on the method employed by NOAA's Pacific Fisheries Environmental Laboratory. Within each of the wind domains, model-derived wind and upwelling estimates agreed with satellite-derived values better than those from geostrophic-derived estimates. To investigate variability between the regional sites, a 9-km-resolution atmospheric model was run for an area off California which spanned four of the regional sites. This high-resolution model, verified with satellite measurements, revealed jets of wind curving and intensifying around coastal promontories. These near-shore wind jets, undetected in the global model, resulted in strong upwelling bands on the order of 50 km alongshore by 20 km offshore. These bands are critical for calculating local upwelling. Our results indicate that regional upwelling estimates for fisheries research can be improved by replacing geostrophic estimates of winds with those from a global atmospheric model. For localized coastal upwelling estimates, however, models with resolution an order of magnitude higher are required.
J Phys Oceanogr, 1992
A linear, barotropic numerical model that features realistic bathymetry of the Scotian Shelf prov... more A linear, barotropic numerical model that features realistic bathymetry of the Scotian Shelf provides solutions forced by steady and periodic wind stress that are generally incoherent on spatial scales of the shelf width. Closed circulation cells occur in d a t i o n with, and on the scales of, major bathymetric features. Bathymetrically steered now is prevalenf and more evident at lower frequencies. Model transport forced by a coastally trapped wave propagating across the backward boundary is not sensitive to the modal structure of the incident wave; bathymetry rapidly modifies the wave form as it propagates in the free diredon. Higher modes and reflected waves are probably dissipated over short distances by scattering and strong bottom stress. Patterns seen in the model solutions are consistent with resulu from more fundamental models, and are readily explained by relatively simple vorticity balances.
suggests that ENSO events are now starting from a higher level, leading to a stronger El Niño (we... more suggests that ENSO events are now starting from a higher level, leading to a stronger El Niño (weaker La Niña) signal in the atmosphere and ocean.
Oceanography, Dec 1, 2013
This report is a summary and preliminary analysis of recent observations of oceanographc and biol... more This report is a summary and preliminary analysis of recent observations of oceanographc and biological struc- ture of the California Current region, with emphasis on atmospheric pressure and wind fields, ocean circulation pattern and hydrographic structure, and upper-ocean plankton distributions. There was a strong transition in atmospheric circulation and sea-surface temperature be- tween the fall of 1994 and wintedspring 1995.
... NEWELL GARFIELD, DAN E. TRACY Department of Oceanography Naval Postgraduate School Monterey, ... more ... NEWELL GARFIELD, DAN E. TRACY Department of Oceanography Naval Postgraduate School Monterey, California 93943 ... Data Buoy Center (NDBC) moored buoys - 46013 (Bodega Bay: 38.2"N, 123.3"W); 46026 (Farallones: 37.8"N, 122.7"W); 46012 (Half Moon Bay: 37.4"N ...
Investigaciones Marinas, 2002
Geophys Res Lett, 2005
State-space models were applied to several climate indices associated with the El Niño-Southern O... more State-space models were applied to several climate indices associated with the El Niño-Southern Oscillation (ENSO), including the Southern Oscillation Index (SOI) and its component sea level pressure series; the NINO3 sea surface temperature index; and the Northern Oscillation Index (NOI). The best models for each series include a significant long-term nonparametric trend combined with a stochastic stationary cyclic term that clearly delineates the El Niño and La Niña events. There is no evidence that the frequency of ENSO events has changed over the 20th century. The long-term trend, however, has contributed to an apparent increase in the magnitude of recent El Niño events. This trend, potentially related to global warming, has increased the level of each series by an amount equal to 30-50% of the amplitude of their corresponding annual cycle or cyclic ENSO term. Thus, the background sea surface temperature in the eastern equatorial Pacific is more than 0.5°C warmer now than prior to 1950, implying a greater overall impact of El Niño events.