A proposal submitted to:
Lead Principal Investigator :
Arthur J. Miller, Research Oceanographer
Climate Research Division
Scripps Institution of Oceanography, UCSD
La Jolla, CA 92093-0224 ajmiller@ucsd.edu.edu
, (858) 534-8033
Principal Investigators :
Fei Chai, Associate Professor of Oceanography,
School of Marine Sciences
University of Maine
Orono, ME 04469-5741 fchai@maine.edu
, (207) 581-4317
Niklas Schneider, Associate Professor of Oceanography,
School of Ocean and Earth Science and Technology
International Pacific Research Center
University of Hawaii
Honolulu, Hawaii 96822 nschneid@hawaii.edu
, (808) 956-8383
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ABSTRACT
Recent work reveals that anomalies of wintertime SST in a large area surrounding the
Kuroshio-Oyashio Extension (KOE) in the northwest Pacific are predictable from the history of wind stress over North Pacific. This predictable component of SST is of interest for North Pacific climate because the KOE is a region of vigorous air-sea interaction, which is linked to large-scale
North Pacific/North American atmospheric climate variability. This predictable component of SST
(and the associated upper-ocean temperature, velocity and upwelling fields) is also of interest because the region has commercially important fisheries that are linked to ecosystem changes driven by this variability of the KOE region.
Important gaps remain in our understanding of the mechanisms involved in the predictable part of the physical-ocean climate variations and in the ways that the atmosphere and marine ecosystems may respond to these predictable changes. These gaps include the path and speed of the planetary waves carrying the predictable signal in the North Pacific, the processes by which these waves change SST, horizontal velocity and upwelling in the North Pacific, the detailed nature of the atmospheric tropospheric response across the North Pacific/North American sector, and the structure of the oceanic biological response. This proposal aims to clarify these issues using a combination of ocean models, coupled ocean-atmosphere models (especially CCSM3), and biogeochemical models, along with in situ and satellite observations of relevant variables.
This research is deeply rooted in NOAA’s CLIVAR agenda and is also relevant to NOAA’s
Global Carbon Cycle program.
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1. Results from Prior Research
We present here very brief statements about a few of the most important results of funded projects over the past three years that are relevant to the proposed research.
NSF OCE-0082543 “ Analysis of Decadal Variability in the North Pacific ” ($498K, 2000-2005 with NCE): Miller and Schneider explored various aspects of decadal variability in observations, simple models and the ECHO-2 coupled model. Major results include demonstrating that the delayed negative feedback loop of the midlatitude gyre mode originally proposed by Latif-Barnett is not active in their updated model (Schneider et al., 2002) and that predictions of SST in the
Kuroshio-Oyashio Extension region are possible with leads up to three years (Schneider and Miller,
2001).
DOE DE-FG0301ER63255 “ Predictability and Diagnosis of Low-Frequency Climate
Processes in the Pacific
” ($970K, 2001-2005 with NCE): Schneider, Barnett, Cayan and Miller explored various aspects of predictability and regional impacts of decadal variability, including influence of the PDO on tropical teleconnections, the emergence of decadal spiciness anomalies in the tropics (Schneider, 2004), regional impacts of decadal variability on ocean biology (Miller et al., 2004a; Di Lorenzo et al., 2004b), and extreme events over western North America.
NOAA NA17RJ1231 “ Consortium for the Ocean’s Role in Climate ” ($137K, 2001-2006),
“ Experimental Climate Prediction Center” ($120K, 2001-2004), and “ North Pacific Climate
Variability and Steller Sea Lion Ecology
” ($250K, 2001-2004 with NCE): Miller worked with many co-investigators on many topics including developing data assimilation techniques for interpreting observations (Di Lorenzo et al., 2004a), building ocean forecasting models (Auad et al., 2004), validating NCEP fluxes against COADS fluxes (Auad et al., 2001), and using physical models in biological applications (McGowan et al., 2003; Miller et al., 2004b).
NSF OCE-01-37272 “ Biogeochemical Modeling of Carbon Partitioning in the Pacific: The
Role of Si and Fe in Regulating Production by Siliceous and Calcifying Phytoplankton
” ($246K for
UMaine, 2002-2005), and NASA NAG-59348 “ Physical variability, ecosystem response and biogeochemical consequences in the Pacific Ocean: understanding oceanic carbon cycling between
1950-2000 ” ($240K for UMaine, 2001-2004): Chai has worked with several co-investigators on these two projects focusing on biogeochemical model development for the Pacific Ocean and investigating the impact of climate variability on biological productivity and carbon cycle in the
Pacific. To date, nine publications have been supported by both NSF and NASA research project
(listed in Chai’s CV and Reference Section).
NOAA NA17RJ1231
“Forecasting Climate Changes over North America From Predictions of
Ocean Mixed Anomalies in the Tropical and Mid-latitude Pacific” ($281K, 2002-2004): Schneider investigated the role of Ekman advection and ocean heat flux convergences in the Kuroshio extension on Northern Hemisphere climate, and explored the forcing of the Pacific Decadal
Oscillation. These results are being prepared for publication.
2. Statement of Work a. Background
The identification of predictive skill in interdecadal climate variability has been a longstanding goal of climate dynamics research. But the bulk of the climate variance in the 10-50 year band in full-physics coupled models and observations appears to be primarily controlled by stochastic
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processes rather than oscillatory feedback loops (e.g., see the reviews by Miller and Schneider
2000; Pierce 2001; Miller et al., 2004a).
Yet in a recent investigation of the mechanisms involved in North Pacific interdecadal climate variability in the Latif and Barnett (1994) ECHO2 coupled model, Schneider et al. (2002) noted that part of the oceanic response in the North Pacific has a predictable component on interannual timescales (Figure 1).This is because the atmosphere, even though it is internally and unpredictably
Figure 1 . (Top) Time series of observed Feb-Mar-Apr
(FMA) SST anomalies in the Kuroshio-Oyashio
Extension (KOE) along 40N, 140E-170E. Connected red dots are observations from the NCEP/NCAR reanalysis; thick red line is the three-year average. The smoothed SSTs are repeated as red line in the center and bottom panels. (Center) Solid black line is the hindcast of SST anomalies using a simple long Rossby equation forced by NCEP/NCAR reanalysis wind stress (see
Schneider and Miller, 2001). Blue line is observed
100m-400m XBT temperature , a proxy for thermocline depth. (Bottom) Retrospective forecasts (green lines) of
KOE SST using a single baroclinic mode Rossby wave model. These three-year forecasts are launched each year and use observed winds up to time zero, and climatological winds for the three forecast years. Green diamonds are the real-time forecasts for FMA of 2004,
2005, and 2006 obtained from reanalysis winds up to
May 2003. (Note the SST forecast skill can be increased by initializing them from observed SST, rather than hindcast SST as done here.) excited, drives open-ocean thermocline anomalies that subsequently propagate westward as baroclinic Rossby waves (e.g., Fu and Qiu, 2002) towards the Kuroshio-Oyashio Extension (KOE) region. It is rather surprising that western boundary current dynamics do not need to be modeled in detail to allow for the effect of these incoming Rossby waves in the KOE region (35N-40N; 140E-
170E). But the hindcast (and forecast) skill clearly shows that wind forcing is the dominant forcing function for 5-30 year timescales in the KOE region.
Figure 2 shows a schematic of this process in the context of large-scale climate variability in the
North Pacific Ocean, the canonical SST pattern, and the Pacific Decadal Oscillation (PDO; Mantua et al., 1997). The ocean response of the Kuroshio Extension accounts for approximately one third of the decadal variance (Figure 3) of the PDO an index of decadal variability of the North Pacific, widely used for climate and biological studies. Understanding the physics of the KOE response, its role in forcing the atmosphere, and its influence on the ocean ecosystem is therefore paramount before attempting to exploit the relationships between the PDO index and fisheries or climate anomalies.
Westward propagating thermocline anomalies are important for climate prediction to the extent that they can influence SST and consequently affect the atmosphere. The KOE region is special in this regard because the mean isopycnals slope strongly upward there, so that baroclinic Rossby waves can readily change isopycnal positioning, which causes SST to be altered as well (Xie et al.
2000; Seager et al. 2001, Qiu 2004). Moreover, Schneider et al. (2002) show that these SST
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anomalies, which are forced by ocean dynamics, vent their anomalous heat content to the atmosphere and influence the rainfall patterns in the northwest Pacific in the coupled model; limited observations suggest that these same atmospheric response mechanisms occur in nature
(Figure 4).
Figure 2 .
(a) Schematic diagram of the canonical pattern of decadal
SST response in the North Pacific. This pattern is largely controlled by, and is in phase with, surface forcing (Ekman current advection, vertical mixing, and surface heat fluxes) by the wind stress associated with a decadal change in the Aleutian Low. It often has a strong correlation with tropical Pacific SST due to atmospheric and oceanic teleconnections. It accounts for a large fraction of the PDO variance. (b)
Schematic diagram of the KOE SST pattern of decadal SST response in the North Pacific. This pattern is largely controlled by the thermocline response to wind-stress curl forcing associated with a decadal change in the Aleutian Low. It has a several-year phase lag with the response in
(a) due to Rossby wave propagation from the central North Pacific to the KOE region. It accounts for a smaller fraction of the PDO variance.
(c) Schematic diagram of the basin-scale thermocline response pattern to wind-stress curl forcing associated with a decadal change in the
Aleutian Low. It tends to be in phase with the (a) in the eastern basin and in phase with (b) in the western basin. Anomalous geostrophic currents follow the thermocline gradients around the gyres. From Miller et al. (2004a).
Figure 3 . Spectra of the PDO index (black), the
PDO reconstruction (red) based on an AR-1 process forced by NINO3.4 (Newman et al.,
2003), the NPI index (Trenberth and Hurrell,
1994), and the KOE advection index (Qiu,
2003). Each of the contributions to the PDO reconstruction are shown separately as colored lines: NPI (green), NINO3.4 (blue) and KOE
(light green). Note that at decadal frequencies, the KOE response contributes significantly to the
PDO variance. From Schneider (in preparation).
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Figure 4 . Precipitation anomalies vs. SST for Jan-Feb-Mar over the KOE region for
(top) ECHO2 coupled model analyzed by
Schneider et al. (2002) and (bottom) observations of Xie and Arkin, thick line smoothed with a five point triangular filter.
Warm SST is associated with enhanced rainfall in both the coupled model and observations. The details of how this local response in rainfall is transferred by the atmosphere downstream across the North
Pacific will be studied in this proposed effort. (Unpublished figure.)
The adjustment of the KOE region to incoming Rossby waves is also of tremendous interest to biologists. Fisheries and other biological communities in the KOE region are clearly influenced by changing oceanic physical conditions, particularly SST (Kawasaki and Omori 1995; Sugimoto and
Tadokoro 1997; Mackas and Tsuda 1999;Yasuda et al. 1999). Biologists have long attempted to link specific physical processes to the ecosystem response. This is especially of interest for explaining basin-scale coherency between fish populations, such as sardines and anchovies, which covary between Japan, the U.S. West coast, and the Peruvian coast (Schwartzlose et al. 1999;
Chavez et al., 2003) and salmon, which covary between the Gulf of Alaska and the U.S. West coast
(Mantua et al. 1997; Hare et al. 1999; Schwing et al. 2002). In the North Pacific, biological modeling suggests that decadal variability can influence primary and secondary production
(Polovina et al., 1995; Chai et al., 2003; Di Lorenzo et al. 2003b). Many observational studies, though, have difficulty going further than noting correlations between SST (or other physical variables) and a given population, due to short, sparsely sampled, or noisy, biological records. b. Scientific Objectives
The identification of a predictable component in midlatitude SST is therefore of great interest to climate dynamics and biological oceanography. However, there are several things that are poorly understood about these potentially predictable signals, including the path and structure of the propagating Rossby waves , the mechanisms by which the incoming Rossby waves alter the physics of the KOE region , the local and remote response of the atmosphere to the KOE SST anomalies through the local ocean-atmosphere feedback, and the ways in which the oceanic biology can react to these physical changes. We therefore propose to expand our understanding of these three key processes in order to more readily exploit the forecasts of KOE SST that can be, and have been, made (Figure 1; Schneider and Miller 2001).
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Specifically, our research will address these four key scientific questions:
(1) What are the processes that determine the lag between central Pacific atmospheric forcing and the arrival of decadal signals in the KOE?
The two-to-five-year lag between anomalous atmospheric conditions in the North Pacific and changes of the ocean conditions in the KOE region has been clearly established from observations, model hindcasts and coupled model integrations (Deser et al. 1999; Miller et al. 1998; Pierce et al.
2001; Seager et al. 2001; Lysne and Deser 2002; Schneider et al. 2002; Qiu 2004). This lag is believed to reflect the propagation of long baroclinic Rossby waves.
However, there is disagreement about the wave paths and speeds (e.g., Liu 1999). On the one hand, Seager et al. (2001) state that a typical westward Rossby wave speed of 1.3 cm/s does not reproduce KOE simulations well and speculate that single baroclinic mode models are not appropriate. In contrast, Qiu (2004) shows that interannual anomalies of sea level observed by satellite altimetry can be well reproduced with a baroclinic Rossby wave model with westward speeds determined from TOPEX autospectra. Schneider and Miller (2001) based their forecasts on a single baroclinic Rossby wave model with a westward speed of 2.5 cm/s faster than expected from a Rossby wave at 40N in a resting background state, but similar to speeds expected in the presence of realistic background baroclinic and barotropic flows (Killworth et al. 1997).
The determination of the path and speed of these waves is critical, since the local phase and amplitude of these waves in the KOE region result from the accumulated atmospheric forcing along the wave's trajectory. Indeed, in very recent work, Qiu (2004) has shown that decadal timescale changes in the strength of Kuroshio zonal currents (and SST) can be due to the different phase speeds of Rossby waves propagating along paths north (38N) and south (32N) of the Kuroshio from the central North Pacific forcing region. His reduced gravity shallow-water model sea level variations correlated well with TOPEX observations of sea level except westward of 160E in the region near and north of the KOE. Non-linear mesoscale eddies likely explain much of this disagreement, but thermodynamic forcing/response, meridional propagation and western-boundary reflection may also be important and these are neglected in his shallow water model.
By investigating full-physics ocean model hindcasts, we will seek to determine the path, speed and planetary wave dynamics of the linkage between Pacific atmospheric forcing and changes in the KOE SST, currents and thermocline structure.
(2) What are the specific mechanisms by which SST in the KOE region is altered by
(predictable) incoming Rossby waves?
The full-physics coupled model analysis by Schneider et al. (2002) suggests that vertical mixing communicates the temperature anomalies in the thermocline to the surface and drives the KOE SST anomalies (which the air sea heat fluxes subsequently damp). But that was for a coarsely resolved
(2.8 degree), strongly viscous ocean model. Qiu (2004), in contrast, showed that incoming Rossby waves control the strength of the Kuroshio current, which supports the previous studies by Qiu
(2000) and Vivier et al. (2002) that showed anomalous geostrophic advection is essential to explaining SST anomalies in the KOE on interannual timescales. Other studies have suggested changes in western boundary current transport (Seager et al. 2001) in the surface layer, or mesoscale eddy dynamics (Qiu and Miao 2000; Dewar, 2001), are more important in controlling long-time variations of KOE SST. Finally, Qiu and Huang (1995) show that horizontal advection across a sloping mixed layer base (so-called obduction) is an important climatological process in the KOE so that zonal shifts of the KOE currents in the presence of strong spatial gradients mixed layer depths may mean anomalous obduction is an important process.
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These upper ocean processes in the KOE need to be understood to translate the predictable
Rossby waves in the thermocline to anomalies at the surface in a physically consistent way. By studying primitive equation ocean model hindcasts in conjunction with observations, we will be in a better position to understand the importance of these large-scale climate processes.
(3) What is the local and remote atmospheric response to the changes in SST induced by the arriving Rossby waves?
Schneider et al. (2002) showed that SST anomalies in the KOE drive a local atmospheric response through surface heat flux forcing, which is especially evident in the rainfall field over the ocean (Figure 4). But the processes by which SST anomalies in the KOE region force the atmosphere are poorly understood (Lau, 1997). The downstream atmospheric pattern of response, which may or may not close a midlatitude decadal oscillatory loop, is highly dependent on this local feedback. Because the atmosphere is particularly sensitive to SST anomalies in the KOE region, where the storm tracks pass over it (Peng et al., 1997), a detailed study of the local and basin-scale structure of the atmospheric response needs to be undertaken in this decadal context of gyre-scale circulation adjustment to Rossby wave arrivals.
We will study these feedback processes in global coupled climate models (especially CCSM3) as a contribution to the coupled model evaluation project (CMEP).
(4) What portion of the ecosystem variability in the KOE region is controlled by the physical response generated by (predictable) incoming Rossby waves?
Biological populations in this region are known to be sensitive to many physical oceanographic changes. These include direct sensitivity to temperature (growth rates, metabolism, spawning grounds, etc.), sensitivity to nutrient inputs due to changes in upwelling or horizontal nutrient transport, sensitivity to advection away from the region (e.g., larval dispersal), and many other hypothesized processes (see, e.g., Miller and Schneider, 2000, and Miller et al., 2004a, for recent reviews). Careful comparison of the predictable part of the oceanic physics with the available biological observations can help to clarify the predictable component of biology. Modeling of the biological response with a multiple nutrients multiple-plankton ecosystem model coupled with circulation model and forced by observed atmospheric forcing can also help to interpret these physical-biological mechanisms in a quantifiable way. These ocean biological changes may also influence the physical climate system through phytoplankton absorption of radiation, which alters mixed layer depth and SST, and phytoplankton DMS fluxes to the atmosphere, which alters cloud condensation nuclei concentrations (Miller et al., 2003; Miller et al., 2004a).
The ecosystem changes in the KOE region are also likely to be linked to other North Pacific regional ecosystem changes by the large-scale response of the ocean to climate forcing. There is overwhelming evidence that climatic shifts in the North Pacific Ocean (e.g., the 1976-77 shift discussed by Trenberth and Hurrell, 1994; Miller et al., 1994) have triggered ecosystem responses
(Mantua et al., 1997; Sugimoto and Tadoroko, 1997; McGowan et al., 1998, 2004; Chai et al 2003).
Widespread ecological changes associated with the 1976-77 climatic regime shift were observed throughout the North Pacific Ocean and the Bering Sea, ranging from plankton to the higher trophic levels (Venrick et al., 1987; Polovina et al., 1994; Francis and Hare, 1994; Limsakul et al., 2002).
Understanding how the structure and phasing of the ocean’s response to climate forcing can organize the basin-wide patterns of ecosystem response and biogeochemical consequences is an important part of the Global Carbon Cycle program.
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b. Proposed Methodology
We propose to address the four key questions (above) by studying the climate-forced physical and biological response in the KOE region using ocean models, coupled climate models, and ocean ecosystem models, along with the available in situ and satellite observations.
Dynamical Response of KOE region to Climate Forcing: Ocean general circulation models will be key tools in our investigations of the ocean's dynamical response in the KOE region to remote (mid-basin) forcing. Key techniques will include detailed analysis of pre-existing ocean model hindcasts (historical scenarios driven by observed forcing), supplemented by targeted numerical experiments designed to isolate the relevant physics. We have experience analyzing several different ocean models in hindcasting scenarios geared towards understanding the largescale response of the Pacific Ocean to observed atmospheric forcing over interdecadal timescales.
We now propose to study these models in the light of the understanding we have gained of the importance of incoming baroclinic Rossby waves and surface/sub-surface linkages in the KOE region.
The Pacific basin-wide ocean model runs whose output we will analyze will include the Simple
Ocean Data Assimilation (SODA) analysis in the Pacific domain (Carton et al. 2000), the MOM hindcasts of Chai et al. (2003), and a Regional Ocean Modeling System (ROMS) hindcast of the
Pacific. Each model has certain benefits in the hindcasting scenarios as follows.
The SODA analysis of the period 1950-2000 is a weak-constraints assimilation of the available surface and sub-surface data in the ocean using the z-coordinate MOM2 (2.5 x 1.5 deg midlatitude resolution) driven by a combination of COADS and NCEP surface forcing. This run is freely available on the web. (A more recent, 0.4 x 0.28 deg, eddy-permitting beta-version of SODA, called SODA-POP, will also be available during the course of this research; Giese, personal communication, 2004). SODA represents the best-guess state of the ocean for each month over the period of the analysis, and provides us with fundamental information of the way the ocean behaved over the time period. Since it has weak constraints, however, the momentum, vorticity and heat budgets include non-physical forcing terms that drive the model towards observations, which means that the physical balances can be obscured by this forcing. Hence we also use freely evolving ocean hindcasts of the Pacific, validated with both the SODA analysis and observations, to better elucidate dynamics.
The Chai et al. (2003; and in preparation) hindcasts incorporate 0.5 to 2 deg resolution versions of MOM with no assimilation. It covers a portion of the Pacific Ocean (45S-65N, 100E-70W) with several of the latest parameterizations by Li et al. (2001). It is forced by monthly averaged wind stress and heat flux from COADS over the period from 1950 to 2000. These runs reside at
University of Maine, and has been studied in several other contexts already. [Note that these runs already has an ecosystem model running along with it as described later.]
We propose to execute a new hindcast using the generalized sigma coordinate ocean model called ROMS (Marchesiello et al., 2001). This will be run at 1-deg (or finer) horizontal resolution and 20-layer vertical resolution over the period 1950-2000 using NCEP forcing (following Di
Lorenzo et al., 2003b) in order to better study the finer-scale details of the incoming baroclinic
Rossby wave son the western boundary current system. [This model may also serve as a precursor to running a regional high-resolution eddy-resolving model of the KOE to be driven by boundary condition specified by the 1-deg hindcast.] We are confident that we can easily execute this hindcast, because we have a great deal of experience now with running ROMS in both openboundary and closed-boundary domains (Miller et al., 2000; Di Lorenzo et al., 2003a,b), including the development of the tangent linear and adjoint model for ROMS (Moore et al., 2003).
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In order to determine if the hindcasts are behaving realistically, they will be validated using the
SODA analysis (3D temperature and velocity fields), satellite observations of sea level (Le Traon et al. 1998; now resident on disk at Scripps), NCEP SST analyses, and subsurface temperature observations (e.g., White, 1997; freely available on the web). Skill scores (correlation, rms error) will be assessed for sea level, SST, sub-surface temperature and currents to determine which simulation is most realistic. Mesoscale noise will, of course, obscure this assessment in the KOE region, but in the central North Pacific and in the regions quite close to the KOE, Fu and Qiu
(2002) and Qiu (2004) have shown that simple 1.5 layer Rossby wave models do a remarkably good job of predicting TOPEX sea level.
Ocean hindcasts with these models must treat air-sea heat flux anomalies in the KOE region carefully. This is because surface heat fluxes in this area act as a damping agent in wintertime, yet act as a forcing agent during the other seasons (Schneider et al., 2002). This is in contrast to most of the extra-tropical Pacific, where they are a forcing term year-round. Prescribing KOE air-sea fluxes estimated from observations in a model hindcast might therefore normally lead to incorrect and misleading anomalies of SST. Instead a model should predict the air-sea fluxes in wintertime since they locally damp SST anomalies in wintertime that are generated by the ocean. This could be accomplished with perhaps a wintertime-only Newtonian damping formulation or with a Seager et al. (2001) formulation of midlatitude heat flux in this region for the proposed ROMS hindcast.
Analysis of the KOE SST heat budget and surface current fields in the individual model runs will be carefully assessed with this knowledge in mind.
In these hindcasts, we will examine the 3-dimensional structure of baroclinic Rossby waves excited by the changes in wind-stress curl in the 8-30 year period band along the latitudinal range of the North Pacific that is relevant to the KOE region. The Rossby waves will be diagnosed in the three-dimensional ocean stream function, estimated from the model's sea level, temperature and salinity (Schneider et al. 2002). Propagating features will be identified by complex empirical orthogonal functions (CEOFs) and extended EOFs (EEOFs). We will determine the generation of the waves by the evaluation of the model's vorticity budgets and comparison with the atmospheric forcing. The propagation path, speed and vertical structure of these waves in the model simulations will be compared to single baroclinic mode, forced Rossby waves as explored for one latitude band by Schneider and Miller (2001) and two latitude bands by Qiu (2004). Is the first baroclinic mode adequate to explain the signals, or are higher modes also important? Is the barotropic mode relevant in any region of the response, such as in the western boundary current? How does the timedependent thermocline state (which is altered by thermodynamic forcing) affect the propagation speed and baroclinic mode partitioning? Via a careful analysis of these model hindcasts we propose to attempt to untangle the physics of Rossby wave propagation and test and reconcile the differing hypotheses.
The impact of the incoming Rossby wave on initiation, spreading and maintenance of the KOE region SST anomalies will be assessed by constructing 3D heat budgets. We seek to determine the relative roles of horizontal advection within the mixed layer, anomalous entrainment and vertical advection at the base of the mixed layer, and anomalous obduction. From the coupled model analysis (Schneider et al. 2002) we expect that the anomalous heat budget is quasi-steady, i.e. that the rate of change of temperature is a small residual term compared to large competing terms of advection, air sea heat exchanges and mixing. The anomalous heat budgets will be compared with the mean and anomalous stream function, upper ocean temperatures and mixed layer depths to relate the balance of heat budget terms to the anomalous currents, thermocline and mixed layer depth associated with arriving Rossby waves. We will determine the interplay of the Rossby wave
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signals with the upper-ocean seasonal cycle including effects such as reemergence (Alexander et al.
1999; Deser et al., 2003) and the dependence of spring and summer anomalies on the previous winter conditions (dubbed ‘footprinting’ by Vimont et al. 2001 in a different context). Model runs will be compared against each other and against observations including SST, XBT and TOPEX sea level.
This analysis of non-eddy resolving ocean models will result in a better understanding of how the KOE region adjusts to incoming Rossby wave son interannual to interdecadal timescales and will point to mechanisms by which the biology may respond. We will also identify the best model response to be used for the ecosystem studies.
Mesoscale eddies, however, are also implicated in controlling long-time scale changes in the physical oceanography of the KOE region. For example, the KOE has been characterized as occurring in bi-modal states, one with primarily zonal flow and one with a strong meander linked to strong southward Oyashio penetration (Qiu 2000). If our large-scale (that is, 1-deg resolution) hindcasts are found to be unsuitable, in that the mesoscale activity cannot be ignored, we will run a regional eddy-resolving version of ROMS in the KOE region to explore the importance of eddies on the long-term changes of SST.
These eddy-resolved runs (if warranted) will be multi-decade runs designed to identify the importance of changes in eddy statistics on interannual SST anomalies. This will be with a nominally10-km resolution version of ROMS (which we have experience using in the CalCOFI region; Miller et al., 2000; Di Lorenzo et al., 2003a,b; and in the Gulf of Alaska; Miller et al.,
2004b). The base climate run (10-20 years in duration) will be driven locally by atmospheric forcing and on the boundaries by climatological Levitus (or better) boundary conditions. The boundary-forced run (also 10-20 years long) will include time dependent boundary conditions specified from the ROMS basin-scale run or the best large-scale ocean model hindcast (likely the
SODA analysis). We will focus on the major KOE event of the mid-1980s that was linked to windstress curl forcing as described by Schneider and Miller (2001) and to the Kuroshio spin-up and spin-down observed by Qiu (2004) with TOPEX during the 1990s and 2000s. Does the arrival of
Rossby waves organize a particular response in the mesoscale (e.g., elongated versus contracted mode, or stronger vs. weaker eddy variance) that is associated with SST anomalies in this region?
By this analysis we will be better able to address key issues of changes in mesoscale eddy dynamics due to large-scale climate forcing in the KOE region.
Atmospheric response to KOE SST Forcing : The details of the atmospheric response to the
SST anomalies induced by incoming baroclinic Rossby waves will be studied in the CCSM3 simulation that is due to become available in early summer or fall 2004. The CCSM3 runs are part of the Coupled Model Evaluation Project (CMEP) of CLIVAR, and include current climate runs along with greenhouse gas forced future climate runs.
Our first step will be to determine the evolution of decadal North Pacific variability in the
CCSM3 simulations for current and future climates. We will calculate the degree to which windforced dynamic ocean processes drive SST variability in the KOE region by investigating the roles of air-sea fluxes of heat and subsurface variability in determining changes of SST. By regression with a KOE regional index, we will then determine the associated pattern of anomalous wind stress, atmospheric pressure, and precipitation over the Pacific, experimenting with few month ocean leads to exclude contemporaneous atmosphere to ocean forcing (Czaja and Frankignoul, 2002). The atmospheric model vorticity, heat, and moisture budgets will then be assessed to determine the influence of this KOE SST forcing.
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This will allow us to build up a coherent picture of the large-scale ocean-atmosphere dynamics involved in low-frequency North Pacific climate variability. We will also be in a position to compare these CCSM3 current-climate results with other runs in the CMEP as well as with our previous results with PCM, ECHO2 and observations. We will repeat the analysis for the 21 st century future climate states of CCSM3 to determine how decadal variability induced by this
Rossby wave process may change in the future. Additional runs of the CCSM3 may be warranted after our analysis, to understand the sensitivity of the atmosphere to KOE SST and its downstream response. We have extensive experience designing and executing these coupled runs on our local
PC clusters at Scripps (COMPAS) and other supercomputers on which we have access.
Ecosystem response to Climate Forcing : Rossby waves originating in the central North Pacific have been shown to force the dominant observed changes in SST and upper-ocean temperature and currents in the KOE region for interannual and interdecadal timescales (Schneider and Miller,
2001; Qiu, 2004). This KOE temperature and current variability has often been implicated in causing ocean biology changes on these same timescales in this region. We propose to follow two major lines of identifying what part of the KOE ecosystem response if directly linked to environmental changes generated by the incoming Rossby waves discussed previously. The first line involves studying an existing hindcast of the ecosystem changes in the North Pacific. The second line involves installing the ecosystem model in the best ocean model hindcast of the KOE physical variability. Both these lines of research will be supported with careful comparison to the available observations of biological variables, including CZCS/SeaWiFS/MODIS chlorophyll-a, in the KOE region.
Our first step in understanding the large-scale part of the ecosystem response to incoming
Rossby waves is to diagnose the North Pacific ocean ecosystem hindcast executed by Chai et al.
(2003). The existing ecosystem model was originally designed for the equatorial Pacific by Chai and his colleagues (Chai et al., 2002; Dugdale et al., 2002; Jiang et al., 2003). The model includes multiple nutrients (NO
3
, PO
4
, Si(OH)
4
, and effects of iron (i.e., modeling iron indirectly following
Chai et al. 2002), two sizes of phytoplankton and zooplankton, nonliving detrital particles, dissolved oxygen, as well as total CO2 (Figure 5). The ecosystem model has been incorporated into the MOM hindcast described in the previous section. The initial conditions for nutrients are from the processed NODC station data by NODC (World Ocean Atlas 2001). Below the euphotic zone, sinking particulate organic matter is converted to inorganic nutrients by a regeneration process similar to the one introduced by Chai et al. (2003) and Jiang et al. (2003), in which organic matter decays to NH
4
and then is nitrified to NO
3
. The flux of particulate material is specified using an empirical function from Karl et al. (1996). The Si(OH)
4
regeneration is modeled through detritus silica (DSi) dissolution process, which depends upon temperature, sinking velocity, and total DSi concentration after Jiang et al. (2003) and Jiang and Chai (2004). The carbon and oxygen cycle are linked with biological productivity and regeneration processes through a Redfield ratio.
Chai and colleagues (Chai et al., 2003; Chai et al., submitted to GRL; Jiang et al., 2003; Jiang and Chai, 2004) have investigated various aspects of the basin-scale ecosystem response to different physical and biogeochemical processes, including the decadal physical forcing changes.
As a preliminary example of the model response to decadal changes in the oceanic physical state, Figure 6 shows a combined EOF of thermocline depth (temperature at 342 m) and 0-100m integrated annual-mean small and large phytoplankton and small and large zooplankton for the region north of 20N. The five variables are treated as a single variable in the EOF analysis, and the two classes of plankton, which are similar in structure, are added together afterwards to simplify the plot. The first EOF is a long-term trend (not shown). The second EOF explains 14% of the total
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combined variance and reveals the major decadal changes of subsurface temperature observed in recent decades after the 1976-77 climate shift. The cuspate signature of westward propagating
Rossby waves producing a westward-intensified response in the KOE region is evident in the 342m temperature fields. The biology responds to this change in upwelling by yielding higher productivity north of the KOE (where there is anomalous upwelling) after the shift and lower productivity after it (where there is anomalous downwelling). Note that the strong biological response in the subtropical front is evident in these plots simply because it is temporally correlated to the SST (not shown; see Miller et al., 2004a). We anticipate that the response in the KOE region is strongly influenced by anomalous upwelling by Rossby waves, while the response in the subtropical front is due to changes in surface mixing causing a deepened mixed layer. The former process has been shown to be predictable, while the latter is probably not predictable.
Figure 5.
The intercompartmental flow chart of the ecosystem and linkage to carbon cycle and physical processes in the euphotic zone, an updated version from the model of Chai et al. (2003).
Figure 6 . Combined EOF of anomalies of annual mean 342m temperature (thermocline depth) and vertical integrals of phyto and zooplankton from the Chai et al. (2003) hindcast. The PC shows the transition to western-intensified cold conditions north of the KOE (Miller et al., 1998) in the 1980s and a switch to warm conditions after the late
1980s. Although the largest biological response is around the subtropical front
(associated with SST changes there, not shown), a coherent large-scale biological response occurs north of Japan and in the
KOE region in response to physical oceanographic changes. The thermocline changes seen here are clearly spatially matched to the biological changes around
Japan and in the KOE region (unlike the SST there). N.b.: The strong biological response around the subtropical front appears here because it is temporally correlated to the thermocline changes but is very likely driven by changes in SST and MLD (Polovina et al.,
1995). From Miller et al. (2004a).
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We propose to further analyze this model run in the context of Rossby wave forcing of the KOE region and its link to decadal-scale climate variability. We will study the ecosystem budgets and use statistical pattern analysis techniques (combined EOFs, complex EOFs, etc.) to link the effects of physical forcing by incoming Rossby waves to the regional ecosystem response in the KOE region and relate the biological changes to thermocline depth, changes in advection etc. explored above. We will attempt to validate the response using the available observations of biology in the
KOE region, including the CZCS/SeaWiFS/MODIS chlorophyll-a observations. We will then use those results to attempt to quantify hindcast and forecast skill of the model and observed biological fields.
The Chai et al. (2003) model gives a good larger-scale picture of the response of the KOE ecosystem to incoming Rossby waves. But in order to obtain a more complete and better resolved picture of the mechanisms involved, we also propose to install an ecosystem model in the best ocean model hindcast of the physical variations. This ecosystem model will likely be the one used by Chai et al. However, we have been also involved for several years in studying the biological ocean response to 3D time-dependent physical forcing using ecosystem models in the CalCOFI region (Miller et al., 2000; Di Lorenzo et al., 2003a). The CalCOFI ecosystem model is already a part of ROMS and consists of a 7-component model including nitrate, phytoplankton, zooplankton, small detritus, large detritus, ammonia and chlorophyll (a non-linear diagnostic quantity), which is a simpler version of the Chai et al. model. We may choose to implement either of these two models depending on their performance in validation tests.
This research will result in a better understanding of the predictable part of the biology driven by incoming Rossby waves. Predictive skill of the ecosystem response to incoming Rossby waves, relative to the total variability of the ecosystem, will be assessed following the skill quantification strategy of Schneider and Miller (2001). If an eddy-resolved KOE response is found to be necessary (see part 2.1), the ecosystem model will be run in these hindcasts with eddy-resolving resolution (roughly 10km). This will help us link the small-scale changes to large-scale driving. c. Work Plan
Year 1: Our efforts will focus on analyzing the output from the ocean model hindcasts and the
CCSM3 current climate runs. In these, we will determine the 3D spatial and temporal structure of the incoming Rossby waves in the KOE region. The SODA analysis will be obtained and analyzed for 1950-2000 changes. The Chai et al. (2003; and in preparation) models will be diagnosed for the
1950-2000 period. The atmospheric response to the KOE SST anomalies will be determined by regression analysis. The ecosystem response of the Chai model will be linked to the part of the flows driven by the incoming Rossby waves.
Year 2: Work will continue on the diagnostic analyses of the ocean model and CCSMS3 hindcasts, and begin on the CCSM3 21 st
century runs. Additional CCSM3 runs will be designed and executed. The ecosystem model will be installed in the best physical ocean model hindcast.
This involves adding the ecosystem components to the ocean model's tracer advection fields. (We have successfully done this before with MOM and ROMS.) An ecosystem hindcast over the last 50 years will be executed and analyzed for the best physical model. We plan on executing these runs on our local alpha workstations and PCs.
Year 3: Final analyses of CCSM3 diagnostics will be completed and physical-biological ocean model hindcasts will be executed. Predictive skill of the oceanic and ecosystem response to incoming Rossby waves will be assessed in the context of total ecosystem variability. If
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appropriate, the eddy-resolved run of the KOE region with and without forcing on the boundaries by the best ocean model hindcast will be executed and analyzed for the impact of incoming Rossby waves on the mesoscale eddies and ecosystem response. d. Coordination of Activities
The work to be carried out within this investigation will be a collaboration among the three institutions, Scripps Institution of Oceanography (SIO), the University of Maine, and the University of Hawaii. Although all three PI’s will contribute expertise and advice to all components, each PI will lead key efforts. Miller and Schneider will work jointly and be responsible for the development, diagnosis and validation of the ocean model hindcasts and forecasts. Scripps Ph.D. student David Mansbach, who will make this a major focal point of his dissertation under Miller’s supervision, will execute the main analysis of the CCSM3 runs. Chai will be responsible for the biological ocean model simulations and for designing modifications to the NPZD model formulations. He will be aided by Scripps biological oceanographer Dr. Neilson who works under
Miller’s supervision.
Communication between SIO and University of Maine will be accomplished primarily by email and telephone. The PIs will also meet regularly, at least once per year, at one of the home institutions and will also occasionally meet at scientific conferences. e. Relevance to the goals of the Climate and Global Change Program
This research is deeply rooted in NOAA’s CLIVAR agenda, including focus on “the large-scale recurrent pattern of the PDO,” “global coupled ocean-atmosphere dynamics,” “understanding global climate variability and potential changes due to climate system feedbacks,” and “developing the observational, theoretical and computational means to predict variability…on seasonal to multidecadal time scales and regional spatial scales.” This research also is relevant to NOAA’s Global
Carbon Cycle agenda, including focus on “quantifying spatial patterns and variability of carbon sources and sinks at the global to regional scales.” f. Benefits to the Public and Scientific Community
The results of our research may have important practical use in improving atmospheric climate forecasting on interannual timescales in the North Pacific and on creating novel forecasts of the ecosystem (including fisheries) in the KOE region of the North Pacific.
Predictions of midlatitude SST at lead times of up to three years are unprecedented. Our proposed research will help us explore in detail the governing physics and exploit this predictive skill by assessing its importance in air-sea feedbacks that may influence decadal variability. If significant retrospective forecast skill in the KOE ecosystem is quantified, actual forecasts of ocean biological response to predicted physical oceanographic changes could be executed. These may prove useful for fisheries managers. g. NEPA Statement
All the research proposed here will be executed in normal university offices, using normal computers, and will not require any environmental assessment or the use of harzardous chemicals.
3. References
Alexander, M. A, C. Deser and M. S. Timlin, 1999: The reemergence of SST anomalies in the North Pacific Ocean. J.
Climate , 12 , 2419-2433.
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Auad, G., A. J. Miller, J. O. Roads and D. R. Cayan, 2001: Pacific Ocean wind stresses and surface heat fluxes from the NCEP Reanalysis and observations: Cross-statistics and ocean model responses . J. Geophys. Res ., 106 , 22,249-
22,265.
Auad, G., A. J. Miller and J. O. Roads, 2004: Pacific Ocean forecasts , J. Marine Sys., 45 , 75-90.
Carton, J. A., G. Chepurin, X. H. Cao, and B. Giese, 2000: A Simple Ocean Data Assimilation analysis of the global upper ocean 1950-95. Part I: Methodology . J. Phys. Oceanogr ., 30 , 294-309.
Chai, F. R. C. Dugdale, T-H Peng, F. P. Wilkerson, and R. T. Barber.2002: One dimensional ecosystem model of the equatorial pacificupwelling system, Part I: model development and silicon and nitrogen cycle. Deep-Sea Res .,
49 , 2713-2745.
Chai, F., M. Jiang, R. T. Barber, R. C. Dugdale, and Y. Chao, 2003:Interdecadal variation of the Transition Zone
Chlorophyll Front, A physical-biological model simulation between 1960 and 1990 J. Oceanography, 59 , 461-
475.
Chai, F., M. Jiang, R. C. Dugdale, T-H Peng, F. P. Wilkerson, Y. Chao, and R. T. Barber, 2003: Ecosystem and carbon cycle modeling in the Equatorial Pacific Ocean, model simulated variability between 1965 and 1992.
Geophys. Res. Lett., sub judice .
Chavez, F. P., J. Ryan, S. E. Lluch-Cota, and M. Niquen, 2003:From anchovies to sardines and back: Multidecadal change in the Pacific Ocean. Science , 299 , 217-221.
Czaja A, Frankignoul C, 2002: Observed impact of Atlantic SST anomalies on the North Atlantic oscillation, J .
Climate , 15 , 606-623.
Deser, C., M. A. Alexander and M. S. Timlin, 1999: Evidence for a wind-driven intensification of the Kuroshio Current
Extensionfrom the 1970s to the 1980s. J. Climate , 12 , 1697-1706.
Deser, C., M. A. Alexander and M. S. Timlin, 2003:Understanding the persistence of sea surface temperature anomalies in midlatitudes. J. Climate , 16 , 57-72.
Dewar, W. K., 2001: On ocean dynamics in midlatitude climate. J. Climate , 14 , 4380-4397.
Di Lorenzo, E., A. J. Miller, D. J. Neilson, B. D. Cornuelle and J. R. Moisan, 2003a: Modeling observed California
Current mesoscale eddies and the ecosystem response. International Journal of Remote Sensing , 25 , 1307-1312.
Di Lorenzo, E., A. J. Miller, N. Schneider and J. C. McWilliams, 2003b: The warming of the California Current:
Dynamics, thermodynamics and ecosystem implications. J. Phys. Oceanogr., sub judice .
Dugdale, R.C., R. Barber, F. Chai, T.H. Peng, and F.P. Wilkerson, 2002: One dimensional ecosystem model of the equatorial pacific upwelling system, Part II: Sensitivity analysis and comparison with JGOFS EqPac data.
Deep-
Sea Res ., 49 , 2747-2768.
Francis, R. C. & Hare, S. R., (1994). Decadal scale regime shifts in the large marine ecosystems of the Northeast
Pacific: a case for historical science. Fisheries Oceanography , 3 , 279-291.
Fu, L.-L., and B. Qiu, 2002: Low-frequency variability of the North Pacific Ocean: The roles of boundary- and winddriven baroclinic Rossby waves. J. Geophys. Res ., 107 , art. 13.
Hare, S. R., N. J. Mantua, and R. C. Francis, 1999:Inverse production regimes: Alaska and West Coast Pacific salmon.
Fisheries , 24 , 6-14.
Jiang, M-S, F. Chai, R.T. Barber, R.C. Dugdale, F. Wilkerson, and T-H Peng (2003). A nitrate and silicate budget in the Equatorial Pacific Ocean: A coupled biological-physical model study. Deep Sea Res.
, 50 , 2971-2996.
Jiang, M-S and F. Chai (2004): Iron and silicate regulation on new and export production in the equatorial Pacific: A physical-biological model study. Geophys. Res. Lett., 31 , L07307. 10.1029/2003GL018598
Karl, D.M., Christian, J.R., Dore, J.E. and al., 1996: Seasonal and interannual variability in primary production and particle flux at Station ALOHA. Deep-Sea Research , 43 , 539-568.
Kawasaki, T., and M. Omori, 1995:Possible mechanisms underlying fluctuations in the far-eastern sardine population inferred from time-series of 2 biological traits. Fisheries Oceanogr ., 4 , 238-242.
Killworth, P. D., D. B. Chelton and R. A. DeSzoeke, 1997: The speed of observed and theoretical long Planetary waves. J. Phys. Oceanogr ., 27 , 1946-1966.
Latif, M., and T. P. Barnett, 1994: Causes of decadal climate variability over the North Pacific and North America.
Science , 266 , 634-637.
Lau, N. C., (1997). Interactions between global SST anomalies and the midlatitude atmospheric circulation. Bulletin of the American Meteorological Society , 78 , 21-33.
Le Traon, P. Y., F. Nadal, and N. Ducet, 1998: An improved mapping method ofmultisatellite altimeter data. J. Atmos.
Oceanic Tech ., 15 , 522-534.
Li, X., Yi Chao, J.C. McWilliams, and L.-L. Fu, 2001:A comparison of two vertical mixing schemes in a Pacific
OGCM, J. Climate , 14 , 1377-1398.
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Limsakul, A., T. Saino, T. Midorikaw, and J. I. Goes, 2002: Temporal variations in lower trophic level biological environments in the northwestern North Pacific SubtropicalGyre from 1950 to 1997. Prog. Oceanogr ., 49 , 129-
149.
Liu, Z., 1999: Planetary wave modes in thermocline circulation: Non-Doppler-shift mode, advective mode and Green mode. Quart. J. Royal Meteor. Soc., 125 , 1315-1339
Lysne, J. and C. Deser, 2002: Wind-driven thermocline variability in the Pacific: A model/data comparison. J. Climate ,
15 , 829-845.
Marchesiello, P., J. C. McWilliams and A. Shchepetkin, Open boundary conditions for long-term integration of regional oceanic models, Ocean Modelling , 3 , 1-20, 2001.
Mackas, D. L., and A. Tsuda, 1999: Mesozooplankton in the eastern and western subarctic Pacific: community structure, seasonal life histories, and interannual variability. Prog. Oceanogr ., 43 , 335-363.
Mantua, N. J. S. R. Hare, Y. Zhang, Y., J. M. Wallace, and R. C. Francis, 1997:A Pacific interdecadal climate oscillation with impact on salmon production. Bull. Am. Met. Soc ., 78 , 1069-1079.
McGowan, J.A., D.R. Cayan, and L.M. Dorman. 1998: Climate-ocean variabilityand ecosystem response in the
Northeast Pacific. Science , 281 , 210-217.
McGowan, J. A., S. J. Bograd, R. J. Lynn and A. J. Miller, 2003: The biological response to the 1977 regime shift in the California Current. Deep-Sea Res., 50 , 2567-2582.
Miller, A. J., Cayan, D. R., Barnett, T. P., Graham, N. E., and Oberhuber, J. M., 1994:Interdecadal variability of the
Pacific Ocean: Model response to observed heat flux and wind stress anomalies. Clim. Dyn ., 9 , 287-302.
Miller, A. J., D. R. Cayan and W. B. White, 1998:A westward intensified decadal change in the North Pacific thermocline and gyre-scale circulation. J. Climate , 11 , 3112-3127.
Miller, A. J., Di Lorenzo, E., Neilson, D. J., Cornuelle, B. D.,and Moisan, J. R., 2000: Modeling CalCOFI observations during El Nino: Fitting physics and biology. Calif. Coop. Oceanic Fish. Invest. Rep.
41 : 87-97.
Miller, A. J., and Schneider, N., 2000: Interdecadal climate regime dynamics in the North Pacific Ocean: Theories, observations and ecosystem impacts. Progr. Oceanogr . 47 : 355-379.
Miller, A. J., M. A. Alexander, G. J. Boer, F. Chai, K. Denman, D. J. Erickson, R. Frouin, A. J. Gabric, E. A. Laws, M.
R. Lewis, Z. Liu, R. Murtugudde, S. Nakamoto, D. J. Neilson, J. R. Norris, J. C. Ohlmann, R. I. Perry, N.
Schneider, K. M. Shell and A. Timmermann (2003): Potential feedbacks between Pacific Ocean ecosystems and interdecadal climate variations., Bull. Am. Meteorol. Soc.
, 84 , 617-633.
Miller, A. J., F. Chai, S. Chiba, J. R. Moisan and D. J. Neilson, 2004a: Decadal-scale climate and ecosystem interactions in the North Pacific Ocean . Journal of Oceanography, 60 , 163-188.
Miller, A. J., E. Di Lorenzo, D. J. Neilson, H.-J. Kim, A. Capotondi, M. A. Alexander, S. J. Bograd, F. B. Schwing, R.
Mendelssohn, K. Hedstrom and D. L. Musgrave, 2004b: Interdecadal changes in mesoscale eddy variance in the
Gulf of Alaska circulation: Implications for the Steller sea lion decline, Atmosphere-Ocean , sub judice.
Moore, A. M., H. G. Arango, B. D. Cornuelle, E. Di Lorenzo, A. J. Miller, D. J. Neilson, The ROMS tangent linear and adjoint models: A comprehensive ocean prediction system, Ocean Modelling , 7 , 227-258, 2004.
Newman M, Compo GP, Alexander MA, ENSO-forced variability of the Pacific decadal oscillation. J. Climate, 16 :
3853-3857, 2003.
Peng, S., Robinson, W. A., & Hoerling, M. P., (1997). The modeled atmospheric response to midlatitude SST anomalies and its dependence on background circulation states. Journal of Climate , 10, 971-987.
Pierce, D. W., 2001: Distinguishing Coupled Ocean-Atmosphere Interactions from Background Noise in the North
Pacific. Prog. Oceanogr ., 49 , 331-352.
Pierce, D. W., Barnett, T. P., Schneider, N., Saravanan, R., Dommenget, D., and Latif, M., 2001: The role of ocean dynamics in producing decadal climate variability in theNorth Pacific. Climate Dynamics , 18 , 51-70.
Polovina, J. J, G. T. Mitchum, N. E. Graham, M. P. Craig, E. E.DeMartini, and E. N. Flint, 1994: Physical and biological consequences of a climate event in the central North Pacific. Fish. Oceanogr ., 3 , 15-21.
Polovina, J. J., Mitchum, G. T., and Evans, G. T., 1995: Decadal and basin-scale variation in mixed layer depth and the impact on biological production in the Central and North Pacific, 1960-88. Deep Sea Res ., 42 , 1701-1716.
Qiu, B., 2000: Interannual variability of the Kuroshio Extension system and its impact on the wintertime SST field . J.
Phys. Oceanogr ., 25 , 1827-1842.
Qiu, B., 2004: Kuroshio Extension variability and forcing of the Pacific decadal oscillations: Responses and potential feedback. J. Phys. Oceanogr ., 33, 2465-2482.
Qiu, B. and W. Miao, 2000: Kuroshio path variations south of Japan: Bimodality as a self-sustained internal oscillation.
J. Phys. Oceanogr ., 30 , 2124--2137.
Qiu, B. and R. X. Huang, 1995: Ventilation of the North Atlantic and North Pacific: Subduction vs.obduction. J. Phys.
Oceanogr ., 25 , 2374-2390.
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Schneider, N., 2004: The response of tropical climate to the equatorial emergence of spiciness anomalies . J. Climate ,
17 , 1083-1095.
Schneider, N. and A. J. Miller, 2001: Predicting Western North Pacific ocean climate. J. Climate , 14 , 3997--4002.
Schneider, N., A. J. Miller, and D. W. Pierce, 2002: Anatomy of North Pacific decadal variability. J. Climate , 15 , 586-
605.
Schwartzlose, R. A., Alheit, J., Bakun, A., Baumgartner, T. R., Cloete, R., Crawford, R. J. M., Fletcher, W. J., Green-
Ruiz, Y., Hagen, E., Kawasaki, T., Lluch-Belda, D., Lluch-Cota, S. E., MacCall, A. D., Matsuura, Y., Nevarez-
Martinez, M. O., Parrish, R. H., Roy, C., Serra, R., Shust, K. V., Ward, M. N., and Zuzunaga, J. Z.,
1999:Worldwide large-scale fluctuations of sardine and anchovy populations. S. Afr. J. Marine Sci., 21 :289-347.
Schwing, F. B., T. Murphree, and P. M. Green, 2002: The Northern Oscillation Index (NOI): a new climate index for the northeast Pacific. Prog. Oceanogr ., 53 , 115-139.
Seager, R., Y. Kushnir, N. Naik, M. A. Cane,and J. A. Miller, 2001: Wind-driven shifts in the latitude of the Kuroshio-
Oyashio Extension and generation of SST anomalies on decadal timescales. J. Climate , 14 , 4249--4265.
Sugimoto, T. and K. Tadokoro, 1997: Interannual-interdecadal variations in zooplankton biomass, chlorophyll concentration and physical environment in the subarctic Pacific and Bering Sea. Fish. Oceanograph ., 6 , 74-93.
Trenberth, K. E. and J. W. Hurrell, 1994: Decadal atmosphere-ocean variations in the Pacific. Clim. Dyn ., 9 , 303-319.
Venrick, E. L., J. A. McGowan, D. R. Cayan, and T. L. Hayward, 1987: Climate and chlorophyll a: long-term trends in the central north Pacific Ocean. Science , 238 , 70-72.
Vimont, D. J., D. S. Battisti and A. C. Hirst, 2001: Footprinting: A seasonal connection between the tropics and midlatitudes. Geophys. Res. Lett ., 28 , 3923-3926.
Vivier, F., K. A. Kelly, L. Thompson, 2002: Heat budget in the Kuroshio Extension region: 1993-1999 , J. Phys.
Oceanogr ., 32 , 3436-3454.
White, W. B., 1995: Design of a global observing system for gyre-scale upper ocean temperature variability. Prog.
Oceanogr ., 36 , 169-217.
Xie, S. P., T. Kunitani, A. Kubokawa, M. Nonaka and S. Hosoda, 2000: Interdecadal thermocline variability in the
North Pacific for 1958-1997: A GCM simulation. J.
Phys. Oceanogr ., 30 , 2798-2813.
Yasuda, I., H. Sugisaki, Y. Watanabe, S. S. Minobe, and Y. Oozeki, 1999: Interdecadal variations in Japanese sardine and ocean/climate. Fisheries Oceanogr ., 8 , 18-24.
4. Budget Justification
Each principal investigator brings synergistic expertise to this project. Miller and Schneider lead the physical ocean and climate modeling side of this proposal, having expertise in designing numerical experiments, analyzing ocean and coupled model physics and comparing results with observations. Chai leads the biological modeling and observations side of this proposal, having expertise in building biological models and driving them with 3D physical variables from primitive equation models.
Mr. David Mansbach is a 2 nd
year Ph.D. student in the Climate Sciences curriculum at Scripps who will make this project a central focus of his dissertation. He will execute the bulk of the coupled model analyses and experiments, and assist with some of the physical ocean model runs and analyses. Dr. Doug Neilson (Ph.D. in biological oceanography, 1995, UC, Santa Barbara) is an ecosystem modeler at Scripps and has been modifying, designing and executing NPZD model runs for many years.
Travel expenses for visiting the University of Maine for collaboration among the PIs and for presenting the results of this work at scientific meetings (e.g., CLIVAR, GLOBEC or PICES) are included. To facilitate the work with the extensive data sets, we request purchase of CPU upgrades for our PC workstations each year.
Project specific costs for supplies and materials (computer tapes, color laser printing charges, etc.) as well as telephone, FAX, mailing, Xeroxing, computer tapes, are also requested. Supply and expense items categorized as project specific are for expenses that specifically benefit this project, are reasonable and necessary for the performance of this project, and can be readily allocable to this project. Funds are also requested for scientific journal publications.
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