Eleni Anagnostou

Institute of Marine and Coastal Sciences, Rutgers University

Boron, Phosphorus, Barium, and Cadmium in Deep-Sea Coral Aragonite – Potential for Reconstructions of Past Ocean Chemistry

Deep-sea corals hold great promise as high-resolution recorders of sub-surface ocean circulation and chemistry in the past.  However, development of proxies for nutrient distributions and carbonate system variables is still in early stages.  We present new data for element/Ca ratios in a small set of modern samples of the solitary coral Desmophyllum Dianthus collected from Atlantic and Pacific regions covering a wide range of nutrient and carbonate system concentrations (depth ~350-1400m).  We used 193 nm laser ablation HR-ICPMS to obtain high-resolution multi-element measurements.  Mean element/Ca ratios were obtained for ablation lines along septa, avoiding the anomalous regions of rapid accretion and the central band, while integrating ~decades of growth.  To test the relationship to seawater chemistry, means for each sample were regressed against hydrographic data from nearby stations.  The P/Ca values showed a reasonable correlation with seawater phosphate (D(PO4)~1.0, where D=El/Ca in coral divided by element/Ca in seawater; R2~0.7).  When a single high point is ignored, D(PO4) decreases to ~0.3 and the correlation improves (R2~0.78), supporting the potential for a direct seawater nutrient proxy.  These D values, however, are far lower than the D~7.0 reported recently by Montagna et al. 1 for the same species, and more consistent with inorganic incorporation of an oxyanion.  The Ba/Ca values show a very strong correlation to seawater Ba/Ca (R2~0.95), with D~1.7, close to that of surface corals.  Skeletal Cd/Ca is similar in range to reported values for surface corals and D(Cd)~1.0.  The skeletal B/Ca values were examined for relationships to carbonate system variables and pH.  We found strong correlation to seawater carbonate ion concentration (R2~0.77), while the correlation to pH is lower (R2=0.5).  No obvious temperature dependence of B/Ca was observed.  These new findings will be discussed in the context of exploring the potential for reconstruction of rapid changes in past nutrient and carbonate system distributions using deep-sea corals. 

Martha W Buckley

Massachusetts Institute of Technology

A Study of the Formation and Restratification of Eighteen Degree Water using Argo Data, SST Observations, and Air-Sea Heat Flux Estimates

Although Eighteen Degree water (EDW) is one of the most studied mode waters in the world ocean, the processes that lead to the formation and dissipation of EDW are not well understood. Estimates of EDW formation from climatological SSTs and air-sea heat fluxes are 15-20 Sv, whereas estimates of rates calculated from float data are only around 5 Sv. The focus of this study is to attempt to reconcile these conflicting results by examining the cycle of convection and restratification in the upper ocean using Argo data together with observations of SST and air-sea heat flux estimates. By better characterizing the processes that are involved in EDW formation, we hope to improve the representation of EDW in climate models. EDW formation is important to climate because the ocean-to-atmosphere heat flux over the EDW formation region may be essential for the maintenance of the Atlantic storm track. Additionally, EDW and the associated Gulf Stream recirculation is a region where oceanic timescales can possibly imprint themselves on the atmosphere.

An examination of SST, air-sea heat flux, and Argo data demonstrates that EDW is formed south of the Gulf Stream in late winter (March). Analysis of all the terms which may factor into EDW formation using the Walin formula shows that air-sea heat fluxes are the dominant process in EDW formation. However, diapynal fluxes by eddies work to counteract air-sea heat fluxes during periods of intense air-sea heat fluxes. For a horizontal diffusivity KH = 1000 m2s−1, the magnitude of the eddy term is about a third of the air-sea heat flux term. Thus, neglect of horizontal diffusion by eddies may help to explain large EDW estimates calculated in previous studies using climatological SST and air-sea heat fluxes. In EDW volume calculations from both Argo data and the Walin formula, EDW volumes are found to peak in late winter (March) and reach a minimum in the autumn. Additionally, over the three years where we have both Argo data and SST and air-sea heat flux data, EDW volumes calculated using Walin and Argo data are observed to be increasing from year to year. However, the annual cycle observed using Argo floats is around 10 Sv, whereas the annual cycle observed from the Walin formula is only 2-5 Sv. The discrepancy between EDW volume calculated from Argo data and the Walin formula is thought to be due to a considerable underestimate of air-sea heat fluxes due to use of an incorrect bulk formula.

Joe Casola

Atmospheric Sciences, University of Washington

Estimating Snowpack Sensitivity to Changes in Temperature

The sensitivity of snowpack to temperature change is defined here as the amount of April 1 snow water equivalent (SWE) that would be lost in particular hydrologic basin for 1˚C of warming during the winter.  Calculations of this sensitivity can be made using:  1) simple geometric considerations of the hydrologic basin, 2) statistical analysis of station observational records of SWE and temperature in past winters, and, 3) a hydrologic model driven by precipitation and temperature data.  The results of the three methods are presented and discussed.  It is proposed that an estimate of SWE sensitivity to temperature change offers a better indicator of the impact of global warming on snowpack than a linear trend in historical observations of SWE

Leigh Ciofani

Earth System Science and Policy, University of North Dakota

Future Climate Change in the U.S. Upper Midwest: An Analysis of Projected Temperature and Precipitation on a Regional Scale 

The effects of climate change will continue for centuries into the future even if greenhouse gas emissions could be halted immediately. Therefore adaptations will be necessary in addition to mitigation in order for humans to effectively deal with the impacts of climate change.  The Intergovernmental Panel on Climate Change (IPCC) developed multiple future emissions scenarios based on several possible socio-economic pathways that society may follow; various Global Circulation Models (GCMs) incorporated these scenarios to develop projections for future climate change.  However, important regional differences in these variables are expected to occur that may be significant on regional scales; global analyses may not reflect such regional differences.

In this study, future regional climate change projections will be analyzed for the Upper Midwest Aerospace Consortium (UMAC), which includes participants in academia, industry and government from the states of Idaho, Minnesota, Montana, North Dakota, South Dakota, and Wyoming.  Because the UMAC region relies largely on agriculture and related enterprises, future climate change could severely impact the economies of the region. Several GCM outputs for surface temperature and precipitation projections incorporating the IPCC’s emission scenarios were obtained.  Two IPCC emissions scenarios were chosen for analysis: the A1FI and B1 scenarios.  These scenarios represent the high-end and low-end emissions estimates, respectively, and therefore provide the extremes of the projected change.  Projections of monthly temperature and precipitation changes over two time frames: 2011-2040 and 2041-2070 were compared with the historical baseline averages for the 20th century (1961-1990).  Additionally, historical data of the 20th century will be analyzed to highlight the changes that have already occurred during the 20th century in this region.  Indications of potential future climate change for the UMAC region can be important for planned adaptation in dealing with climate change impacts.       

Sarah E. Cullison1, Michael D. DeGrandpre1, & Chris Langdon2

1Chemistry, University of Montana, 2Rosenstiel School of Marine and Atmospheric Science, University of Miami

Understanding Global Warming: Using Autonomous Sensors to Study the Ocean Carbon Cycle

Determining the global sources and sinks of CO2 is important for understanding the global carbon cycle as well as for finding a solution to rising atmospheric CO2 levels.  The oceans regulate atmospheric CO2 to a large extent, making the ocean CO2 cycle of great interest. In an effort to better understand carbon cycling the Submersible Autonomous Moored Instrument for CO2 (SAMI-CO2) and the SAMI-pH were previously developed by DeGrandpre et al. (1995) and Martz et al. (2003) to measure aquatic partial pressure of CO2 and pH, respectively.  The SAMI-CO2 and SAMI-pH data are used to quantify the processes that control the air-sea flux of CO2, diel and seasonal pH and CO2 cycles, and to quantify total alkalinity (AT) and dissolved inorganic carbon (DIC).  While AT and DIC are typically determined from grab samples, collecting these samples even once a day for an extended period is very costly and time consuming.  The deployment of these autonomous sensors eliminates the need to collect grab samples for inorganic carbon studies.   The SAMI-CO2 and SAMI-pH are deployed in tandem for the first time on a coral reef in Puerto Rico, allowing the determination of a baseline for normal pH and CO2 variation, both daily and seasonally on a coral reef.  This data will also produce the first long-term, high-temporal resolution measurements of calcium carbonate saturation index on a reef.

Michael G. Davis1, Robert N. Harris2, David S. Chapman1

1Geology and Geophysics, University of Utah, 2Oceanic and Atmospheric Sciences, Oregon State University

Geothermics of Climate Change: Linking Ground and Air Temperature Change Through Repeat Temperature Measurements in Boreholes from Northwest Utah

Temperature-depth profiles measured in boreholes contain important information about the Earth’s changing surface temperature and provide a direct method for reconstructing surface temperature variations over the past several centuries.  Temperature logs, repeated over a decadal timescale, provide an important test of borehole thermometry when observed transients in the temperature profile are compared with the subsurface transients predicted from the surface temperature changes.  Twelve temperature-depth profiles at the northwestern Utah Emigrant Pass Observatory (EPO) borehole, GC-1, and three at the boreholes SI-1 and DM-1, were acquired between the years 1978 and 2007.  These boreholes are 150 m deep and over the 29-year period subsurface temperature variations extend to about 100 m that we attribute to changes in surface air temperature (SAT).  SAT data from the meteorological station at EPO and nearby Historical Climatology Network stations are used as a forcing function at the Earth’s surface and diffused into the subsurface.  These transients reproduce observed subsurface temperature variations reasonably well at each borehole.  Snow events over this time period seem to have little influence at these time and depth scales.  Observations of the tracking of ground surface temperature (GST) and SAT at EPO, as well as repeat temperature logging of boreholes, offer strong support for using GST histories to complement SAT data and multi-proxy reconstructions in climate change studies.

Pedro Di Nezio

University of Miami

The Role of the Upper Ocean Dynamics in the Response of Tropical Pacific Climate to Warming

The role of upper ocean dynamics in the response of the tropical climate to global warming is analyzed using numerical simulations from the Program for Climate Model Diagnosis and Intercomparison (PCMDI). Analysis of the General Circulation Model (GCM) output from this program suggests that the ocean dynamics plays an important role in the response of the zonal sea surface temperature (SST) gradient of the Pacific Ocean to doubling of CO2 concentration. Moreover, significant discrepancies are identified among models, consistent with complex ocean dynamics identified in previous studies.

The main objective of this study is to quantify the ocean contribution to the sensitivity of the equatorial SST under future scenarios driven by increased CO2 concentrations. Among the mechanisms governing the equatorial SST equilibrium response to warming, two of them appear to be dominant according to previous studies. The ocean ‘dynamical thermostat’ stands as an important process modifying the equatorial SST gradient with origin in the ocean dynamics. Simultaneously, a weakening of the Walker Circulation induced by changes in the hydrological cycle, has been identified as an important primarily atmosphere- driven process controlling the mentioned SST gradient.

As climate warms, these two competing mechanisms, and possibly others, drive changes in both the atmospheric and ocean circulation over the tropical Pacific Ocean. The first leads to a strengthening of the East-West SST contrast, resembling ‘La Niña’ conditions, while the second leads to a weakening of the mentioned SST contrast, contrast resembling ‘El Niño’ conditions. In order to shed light into these opposing effects, the heat budget of the mixed layer is compared across models aiming to not only quantify the role of the ‘dynamical thermostat’ but also identify or rule out other mechanism controlling the SST response. Although, the focus of this study is on the time-mean response of the zonal SST gradient of the equatorial Pacific, changes of this gradient do not necessarily imply a change in frequency or intensity of individual El Niño/La Niña events. However, understanding the interplay between the two effects is important to determine the behavior of this crucial mode of climate variability of important societal impact, since El Niño not only affects weather phenomena including tropical cyclone activity and global patterns of drought and flood but also agricultural productivity and oceanic biological activity.

Jessica Drees

Earth and Space Sciences, University of Washington

An Inverse Approach to Interpolating an Ice Core Depth-Age Relationship

Often Antarctic ice cores can be dated at only a few discrete depths; however, it is desirable to have a physically based interpolation of the depth-age relationship between the sparse dated points.  Piece-wise linear or spline interpolations can introduce serious error, because they do not properly account for the variation of dynamical strain with depth due to ice flow, and they do not account for temporal changes in accumulation rate.  We use an inverse-theory approach incorporating ice dynamics to find a set of model parameters defining an accumulation-rate history that reproduce the measured depth-age data in some “best” sense.  Solving the forward problem produces a depth-age relation, from a given accumulation-rate history.  Our initial forward model for ice divide cores is a one-dimensional kinematic ice-flow model with constant ice-thickness.  Vertical velocity is specified through the accumulation-rate history combined with velocity shape functions, which may be time-dependent.  The accumulation-rate history in the flow model produces a more realistic interpolation of the measured depth-age data.  Extensions to the transient ice-sheet thickness are straightforward.  Here we produce a depth age relation for the Siple Dome ice core using layer-counting and sparse ages of occluded gases (CH4 and O2).

Katie Fagan

Oceanography, University of Washington

Variability in the Surface Water Inorganic Carbon Parameters of a Hawaiian Coral Reef System and Implications for Calcification Rates

The partial pressure of carbon dioxide (pCO2) in the atmosphere has been increasing since the industrial revolution.  When atmospheric CO2 mixes into the surface ocean, CO2 reacts with water to form carbonic acid which lowers the pH of the ocean.  The pH of the world ocean has dropped by about 0.1 since pre-industrial times.  It has been shown that the calcification rates of corals decrease with increasing pCO2 and predicted that by 2100 coral calcification rates may decrease by 30%.  The inorganic carbon parameters of a coral reef system in Hawaii (Kaneohe Bay, on the island of Oahu) have been monitored from 2003 – 2004 and from December 2005 – present.  A time series study was performed from September 2003 through September 2004 in which 23 locations throughout the bay were sampled every other week for total alkalinity and dissolved inorganic carbon analyses.  In addition, a CO2 mooring was installed in southern Kaneohe Bay in December 2005 and has been collecting data almost continuously since that time.  The CO2 mooring collects air and surface seawater pCO2 and O2 and surface water temperature and salinity data every three hours.  Surface water pCO2 in Kaneohe Bay is extremely variable, ranging from 160 to 780 ppm.  pCO2 values were above the atmospheric level most of the time, making Kaneohe Bay a net source of CO2 to the atmosphere.  This is most likely due to calcification by the abundant coral reef system in the bay since calcification produces CO2.  Low surface water pCO2 values were only observed following storm events which bring excess nutrients to the bay, via increased stream flow, that stimulate photosynthesis.  We are currently planning experiments to measure calcification rates of the main reef system in Kaneohe Bay (the barrier reef) in order to verify that calcification is the main process responsible for the high CO2 levels in Kaneohe Bay.  This calcification rate study will also provide data that will be used to determine the pCO2 level at which the barrier reef may switch from net calcification to net dissolution as atmospheric and seawater CO2 levels continue to rise in the future.

Jacob Haqq-Misra, Shawn Domagal-Goldman, Patrick Kasting, & James Kasting

Astrobiology Research Center, Pennsylvania State University

Greenhouse Warming of the Archean Earth

Geologic and biologic evidence suggests that the Earth was warm during its early history, despite the fainter young Sun. Paleosol data place constraints on the atmospheric CO2 present in the Archean, suggesting additional greenhouse mechanisms may have been in place. Methanogenic bacteria present in the anoxic Archean may have contributed to a high concentration of atmospheric CH4, providing an additional source of greenhouse warming, but CH4 alone cannot produce warm Archean surface temperatures. In a low-oxygen environment, however, atmospheric photochemistry will produce higher order hydrocarbons including C2H6, with concentrations of 1-10 ppmv. C2H6 has strong absorption in the atmospheric window region, providing additional greenhouse warming and allowing above-freezing surface temperatures for the Archean. The inclusion of C2H6 absorption and the formation of an organic haze layer indicate the warm climate of the Archean may have been sensitive to the biogenic flux of CH4 from methanogens, an interplay between the climate system and the biosphere.

Paul Hezel

Atmospheric Sciences, University of Washington

Proxy Reconstruction of Sea Ice Extent

Sea ice extent plays an important role in the global energy balance and therefore has significantly affects climate.  There is however, no straightforward record of past sea ice extent, and therefore the potential role of sea ice in past climates is not well understood.  Studies used dinoflagellates, ice rafted debris, and other mechanisms to infer extent and sea ice motions in particular areas.   I will present preliminary work to use methansulfonic acid (MSA) as a proxy indicator of sea ice extent in the Southern Ocean around Antarctica.  MSA is an oxidized form of dimethyl sulfide (DMS), a product of biological activity in the ocean, with increased concentrations in the sea ice zone around Antarctica.  Chemical transport and deposition studies, a regional climate model, the satellite record of ice extent, and timeseries analysis of MSA in ice cores to determine whether MSA has further potential as a proxy for sea ice extent. 

   

Hsun-Ying Kao and Jin-Yi Yu

Earth System Science, University of California, Irvine

Verifying Two-Oscillator Mode of ENSO from the Decadal Changes in ENSO Persistence Barrier

The aim of this project is to present a distinct view of El Nino Southern Oscillation (ENSO). Instead of a typical delay oscillator mode, a new two-oscillator mode is presented in this study. From the examination of decadal changes of persistence barriers in various indices of sea surface temperature (SST), it is noticed that the SST indices in the eastern and central equatorial Pacific present distinct decadal barrier variability. The eastern Pacific SST (NINO1+2 and NINO3) experienced significant decadal variation in the past fifty years. In contrast, the central Pacific SST indices (NINO3.4 and NINO4) went through negligible decadal barrier changes in the same period. This phenomenon is corresponding to the decadal changes in the propagation directions of ENSO SST. The results imply that ENSO SST anomalies in the equatorial Pacific can be considered to consist of two different processes: a central Pacific process whose phase transition and barrier always happen in spring, and an eastern Pacific process whose phase transition and barrier change from decade to decade.

The two processes are influenced by different systems. The eastern Pacific process is more correlated with the subsurface ocean. The zonal mean OHC index averaged over the equatorial Pacific shows decadal barriers variation similar to those in the eastern Pacific SST indices and always leads the NINO3 SST barrier by about one season. On the other hand, the central Pacific process is more correlated with Indian-Australian monsoon. Model experiments demonstrate that the Indian-Australian monsoon is relevant to the quasi-biennial component of ENSO signals and has substantial correlations with central Pacific process but not with eastern Pacific process. Understanding the two-oscillator view can not only describe the ENSO phenomenon more precisely but also improve ENSO prediction.

Michèle LaVigne

Institute of Marine and Coastal Sciences, Rutgers University

Seasonal P/Ca Cycles in a Gulf of Panama Upwelling Coral Skeleton: Evidence for a New Seawater PO4 Proxy

A proxy for surface water nutrient concentrations, recorded in coral skeleton, would provide sub-seasonal resolution records crucial to understanding oceanic nutrient and primary production variability on decadal to centennial timescales.  Records of tropical euphotic zone nutrient supply and uptake dynamics could link decadal-centennial scale climate oscillations to low latitude carbon fixation and sequestration more directly than can be achieve using available paleo-SST/upwelling proxies alone.  A direct coral proxy for seawater phosphate would complement records from established but quantitatively uncertain indirect surface water nutrient proxies such as planktonic foraminiferal Cd/Ca and coral Cd/Ca and Ba/Ca.  Using both solution phase and laser ablation ICP-MS methods, we have found that average skeletal P/Ca in surface corals of different species growing in regions with distinct nutrient regimes (the Gulf of Panama (Pavona gigantea), Martinique (Montastrea faveolata), and Rarotonga (Porites lutea)) appear to describe a linear relationship with ambient surface phosphate.  A 4-year record along the growth axis of the Pavona gigantea coral growing under seasonally varying nutrient levels in the upwelling regime of the Gulf of Panama shows repeated annual cycles of P/Ca in the coral.  Skeletal P/Ca ranges from ~10 -90 umol P/mol Ca with maxima occurring during cool upwelling periods, changing in proportion to known variations in surface water phosphate (~ 0.2 to 0.8 μM seasonally).  Our preliminary data are the first to indicate that a quantitative relationship exists between surface seawater phosphate levels and coral skeletal P/Ca (D~2 vs. deep sea coral D~7).  Based on rigorous solution cleaning and soluble reactive phosphate analyses of drilled powders, we hypothesize that the P/Ca signal measured by ICP-MS is controlled by an organic intracrystalline phase that reflects ambient seawater phosphate.  We plan to further investigate the specific incorporation mechanism of P in coral skeleton and test the validity of this new proxy in corals of different ages and nutrient environments (Florida Keys, modern, and fossilized Line Island corals).  These continuing efforts will help reveal the future utility of coralline P/Ca as a seawater PO4 proxy.

Heather Lazrus1 & Annie Bartos2

1Anthropology, 2Geography, University of Washington

“It’s Getting Hot in Here!”: Social Science Research on Climate Change

The natural sciences have been pushing disciplinary, epistemological, and policy boundaries through groundbreaking research on global climate change.  Current and future research in the social sciences is needed to consider the human dimensions of climate change.  Social science research can contribute to understanding the intersections of natural science research with the cultural, social, economic and political textures of people living now and in the future landscapes created by climate change.  Social science methodologies complement natural science research by focusing on the everyday experiences of people, how people perceive climate change, and how people make sense of climate change. In our poster, we argue that it is important to include social science research in the study of climate change for three significant reasons.  Firstly, a social science dimension to climate change research allows a critical collaboration between traditional environmental knowledge and qualitative observations with more quantifiable climate science occurring in particular landscapes.  Secondly, more research is needed to understand how traditional and spontaneous adaptation mechanisms at individual, household, and community scales can help prepare for current and future disaster risk reduction. Finally, it is important to understand the ways that climate change is being taught in schools, as children will undoubtedly be living in landscapes different from those of their parents.  In turn, climate change education will be an important strategy through which future landscapes will be created.  Although a global phenomenon, local climate change impacts will be (and are already) varied and diverse.  Therefore, our poster will discuss our three rationales for social science research in three spatially and economically differentiated locations.  All of these locations are currently and will continue to experience tangible effects of climate change.  Case studies are drawn from on a developed nation (New Zealand), a least developed country (Tuvalu), and a native population within a developed country (Alaskan Native communities).

Chris Little1, Anand Gnanadesikan2, & Robert Hallberg2

1Geosciences, Princeton University, 2NOAA/Geophysical Fluid Dynamics Laboratory

Utilizing idealized ocean models to understand ice shelf basal melting patterns

The melting of ice shelves from beneath constitutes a loss of ice from the cryosphere and a source of freshwater to the ocean; it also influences ice sheet dynamics. Antarctic ice shelves can be roughly described by two regimes (“warm” and “cold”), characterized by dramatic differences in spatial extent, basal melting rates, and sub-shelf oceanographic conditions.  This poster presents an overview of these regimes and describes two sets of idealized experiments undertaken to reveal key oceanic controls on basal melting.

In simulations of idealized “cold” shelves, asymmetry in melting is driven by oceanic constraints on inflow at depth. Near the grounding line, inflow is diverted by upwelling-induced cyclonic flow. This recirculation and resultant melting pattern are insensitive to changes in bathymetry.  In a second set of simulations under an idealized “warm” ice shelf, oceanic heat is present near the ice interface. The dynamics of the ice-ocean boundary layer (and its model representation) is thus critical to determining where and how much melting occurs. Melting is intensified in areas of strong near-boundary flow and is highly sensitive to turbulence parameterizations.

These examples illustrate how idealized numerical models may help isolate the mechanisms – sub-shelf thermodynamic and dynamic controls, tides, winds, and open ocean dynamics -by which heat drives basal melting. These simulations may also be used to examine sensitivity to changes in model formulation, configuration, and parameterizations, improving our confidence as we look towards realistic, coupled studies of ocean-ice shelf interaction.

Mira Losic

Geography, University of Calgary

Glacial Energy Balance Study in the Canadian Rockies

All of the Alberta’s major rivers are supplied with water from the Rocky Mountains.  The potential effects of predicted glacier retreat and earlier peak snow melt in the season could crucially change mountain river flows, providing part of the motivation and rationale behind trying to better understand the governing processes of mountain headwater watersheds.  Glacier melt runoff does not typically contribute large amounts to alpine streams, however in the later months of the summer when most of the snow has melted, the contribution becomes much more significant.  As the climate of the Earth warms it becomes essential to understand the potential effects of increased glacial melt runoff.

Solar radiation is the largest source of melt energy to alpine glaciers.  Given this it is imperative to understand surface albedo evolution, both spatially and temporally.  The objective of this study is to improve the understanding of glacier energy balance with an emphasis on albedo evolution and the role of melt water storage and refreezing on glacier surfaces. The overarching long-term goal is to incorporate the findings of this study into a much larger, broader study of alpine hydrology, which hopes to understand the function of snow and glacier melt in supplying the source water of mountain rivers, and to develop numerical models describing hydrological processes in the alpine headwater region.

In this coming summer season, I will be conducting field experiments at two glaciers in the Canadian Rockies that will examine energy balance components in greater detail than in previous studies.  Preliminary data characterizing albedo evolution, melt percolation patterns, overnight refreezing and morning thaw, and turbulent heat flux measurements will be processed and modeled in order to develop a more comprehensive energy balance regime.

Johnnie Anna Lyman

Scripps Institution of Oceanography

Modeling Potential Carbon Release from the Arctic Ocean at the Paleocene-Eocene Boundary

The Paleocene-Eocene Boundary is marked by an approximately 2‰ negative excursion in ODP Core 690.  Explanation of the Paleocene-Eocene Carbon Isotope Excursion has been poor.  An event such as overturning of a large, anoxic enclosed basin would explain the excursion.  This event has been modeled using the modern Black Sea as an analog for the Paleocene-Eocene Arctic Ocean.  A warm Arctic with Black Sea-like deposits of organic carbon could be capable of storing over 4000Pg of carbon for a single release if oxidation of this organic carbon took place to a depth of 25cm.  If oxidation took place down to only 10cm, this number would be reduced to 1600Pg.  However, this is still a possible source for the Paleocene-Eocene excursion, since the event consisted of not a single output event, but two smaller output events, as recorded in both DSDP Core 401 and at Bighorn Basin in Wyoming, USA. 

A source such as an overturning basin would be likely since there have been many such excursions in Earth’s history, including events such as the ELMO event in the early Eocene.  Multiple releases over time would be easily explained by multiple overturning events as the hydrological cycle changed.  These overturning events could take place in smaller basins as well, perhaps helping to prolong the PETM event, as well as to create the many smaller events seen throughout Earth’s history, thereby replacing the clathrate gun hypothesis and eliminating a need for large clathrate storage capacity in a warm ocean. A source within the natural carbon cycle may help explain the rapid recovery of these events through sequestration within an anoxic basin.  This eliminates the need for silicate weathering to dictate the speed of removal of carbon from the system, as would be the case for carbon from a previously deeply buried source. 

Stephanie Mumma1, Cathy Whitlock1, & Kenneth Pierce2

1Paleoecology Lab, Department of Earth Sciences, Montana State University, 2USGS, Northern Rocky Mountain Science Center

Preliminary Data on a Long Sediment Core from Lower Red Rock Lake, Southwest Montana

Understanding the biotic response to past climate is important for assessing the ecological impacts and feedbacks associated with future climate change.  Although marine paleoclimate sites dating back to the last full-glacial are generally well-distributed, terrestrial sites of this age are sparse, especially in the Rocky Mountain region.  A recently acquired lake-sediment core from Lower Red Rock Lake (LRRL) located within Red Rock Lakes National Wildlife Refuge in the Centennial Mountains of southwest Montana provides an opportunity to examine vegetation changes since the last full-glacial (Pinedale) in the northern Rocky Mountains.  An AMS radiocarbon date from exposed lacustrine sediments in the basin have a calibrated 14C age range of 19,512 – 20,053 cal yr BP, and these lithologic units are correlated with sediments at a depth of approximately 809-cm in the lake-sediment core.  This correlation implies that the lake-sediments extend back to the culmination of alpine glaciation in the region.  Three more AMS 14C dates are pending, and three ash layers have been submitted for tephrochronology analysis.  Fossil pollen will be used to reconstruct regional temporal variation in vegetation, and loss-on-ignition values will estimate organic content since the last glacial maximum.  Magnetic susceptibility has been measured, and will provide information on allochthonous sediment input in the basin. The full-glacial, late-glacial, and Holocene record at LRRL will contribute to the climate and vegetation history of intermontane basins in the western US.  This investigation will also yield beneficial information on the history of the basin for land-use managers of Red Rock Lakes National Wildlife Refuge. 

David Nicholson, Steve Emerson & Charlie Eriksen

Oceanography, University of Washington

Biological Oxygen Production in the Subtropical North Pacific Gyre from Autonomous Seaglider  Measurements

Seagliders, deployed through most of 2005 in the subtropical North Pacific gyre, made measurements of temperature, salinity and dissolved oxygen to quantify net biological oxygen production at Station ALOHA of the Hawaii Ocean Timeseries.  The Seagliders were equipped with both Seabird Electronics SBE43 and Aanderaa Optode dissolved oxygen sensors.  We calibrated these sensors using Winkler titration oxygen measurements from the HOT program.  An objective analysis mapping technique interpolates these oxygen, temperature and salinity measurments to a regular grid to be used in a mass balance calculation of biological oxygen production.  Observations show that Rossby wave activity at Station ALOHA drives heaving of isopycnals near the base of the euphotic zone.  Such vertical displacements of isopycnal is demonstrated to be a primary control on net biological oxygen production and thus carbon export in the deep euphotic zone.   Net biological oxygen production in the deep euphotic zone was 0.9 to 1.5 mol O2 m2 yr-1.  This production rate accounts for 17 to 25% of net biological oxygen production at Station ALOHA with the other 75 to 83% occurring in the mixed layer.

Courtney O'Neil

Civil and Environmental Engineering, University of Washington

Database Development of GCM Based Climate Scenarios for Use in Hydrologic Resource System Impact Evaluations

Members of TAG (The Alpheus Group) at the University of Washington have been working with the Climate Change Technical Committee to development a consistent set of meteorological and hydrological data that can be applied in water resource evaluations in the future.  In this research, data will be generated to estimate the future impacts forecasted using three different General Circulation Models (GCMs) that include two emission scenarios, for time periods associated with the years 2000, 20205, 2050, and 2075.  The regional scale climate data will be derived from GCM simulations that were downscaled to local station points in the Puget Sound region.  This downscaled climate data can then be used in simulations to evaluate water resource climate change impacts.

To facilitate the general use of these data, the data will be organized and maintained in an easily accessible database.  Entrée to the database will be provided through a website that will be developed by the researchers.  The primary objectives of the database and webpage are to:

-Provide access to precipitation, temperature, and streamflow data at pseudo weather stations and pseudo stream stations for climate impacted periods, including 2000, 2025, 2050, 2075,

-Provide interactive graphic and analysis tools for illustrating the trends for precipitation, temperature, and streamflow at specific stations, and

-Provide interactive graphic and analysis tools for illustrating regional trends for precipitation, temperature, and streamflow

The website is in draft form at www.climate.tag.washington.edu

Sandra Penny

Atmospheric Sciences, University of Washington

The Influence of Orography in Asian Cyclogenesis

The vast areal extent of high midlatitude elevations in Asia and the mechanisms governing mountain-climate interactions in the area have many important consequences for the understanding of modern regional climate variability. On a geological timescale, the history of the evolution of the Tibetan plateau and the geography of the surrounding areas, as well as the sensitivity of Southeast Asia's monsoon to the orography that controls it depend on an understanding of the climate processes in the region. We consider one example: cyclogenesis in the lee of the Mongolian Altai mountains is the dominant mechanism for storm formation in Southeast Asia. They have been the focus of numerous theoretical, numerical, and observational case studies, although most considered only individual events and few considered Asia. To our knowledge the climatological effects of persistent lee cyclogenesis have not been investigated. We develop a metric of lee cyclogenesis in Southeast Asia and use it to investigate the connections between interannual variability in other measures of Asian and Pacific climate.

Jonathan Petters

Meteorology, Pennsylvania State University

Impacts of Three Dimensional Radiative Transfer on Modeled Cloud Dynamics

The interaction of clouds and radiation is recognized as a source of great uncertainty in estimates of climate sensitivity made through the use of general circulation models (GCMs).  Atmospheric radiative transfer in GCMs is currently modeled with the one dimensional (1D) Independent Column Approximation (ICA), where radiation is allowed to propagate only vertically, not between model columns.  ICA is currently favored for two reasons.  First, modeling radiative transfer in three dimensions (3D) is computationally expensive.  Second, when compared to 3D results averaged over scales explicitly resolved by GCMs, ICA gives results that compare well for many modeled cloud fields.  However, 3D radiative transfer may have impacts on cloud dynamics at scales unresolved by GCMs, and these impacts could influence simulations of climate. 

In this study we explore the impacts of two-dimensional radiative transfer on modeled cloud dynamics using the Regional Atmospheric Modeling System (RAMS).  In RAMS atmospheric radiative transfer is currently modeled with ICA.  We are incorporating a radiative transfer solver into RAMS that models 2D or 3D radiative transfer in the solar wavelengths using a Monte Carlo approach.  Solutions found with Monte Carlo approaches are accompanied by an amount of random error, and this random error lessens with increasing computational expense.  We explore this impact a priori by perturbing radiative heating rates calculated with ICA during runtime with varying amounts of random noise.  We investigate the effect of this noise on the evolution of cloud properties in several 2D RAMS simulations.  These ‘noisy ICA’ runs serve as a proxy for modeling atmospheric radiation with the Monte Carlo approach. 

Austin Polebitski1, Richard Palmer2, Matthew Wiley3, Courtney O'Neill1, Ben Enfield1, Kathleen King1, and Lee Traynham1

1Civil and Environmental Engineering, 2Civil and Environmental Engineering, University of Washington, 33Tier Environmental Forecast Group, Seattle

Development of Climate Change Building Blocks for Use in Regional Planning

For engaged stakeholders and city, county, state, and tribal governments to plan for and address the potential impacts of climate change, it is imperative that decision makers develop an understanding of the likely impacts of global warming and strive to communicate these impacts to the public with a common vocabulary. This can be extremely difficult due to the intricacies of the physical processes that underlie climate change, to the limited education the general public receives in the basic sciences, to the evolving nature of our understanding of climate change, and to the more general challenge of communicating complex, scientific issues. Despite these challenges the development of a basic appreciation of the potential impacts of climate change is necessary to adequately plan for the future.

A three county, water supply planning process in Western Washington has identified the need to distill the vast body of literature on climate change that is available into a series of simple building blocks that can be used to educate and inform the general public and stakeholders and decision makers. The goal of this effort was to identify the most salient observations that have been made in the peer reviewed literature during the past two decades of research. This information will be used to identify what is known at a global, regional, and watershed level in regards to the impacts of climate change on water resources.

This paper describes the process by which the thirteen building blocks were constructed and the sources of information that were used. The primary areas that are addressed include climate change impacts on temperature, precipitation, snowpack and glaciers, streamflows, sea level, and on salmonid habitat and populations. The participants in this process represented a wide range of government organizations, and the participants began the process with varying ranges of formal background in the subject. Through a series of facilitated workshops, the group was able to arrive at the building blocks that are now being used to help incorporate climate change impacts into regional water supply planning.

Shraddhanand Shukla & Andrew W. Wood

Civil and Environmental Engineering, University of Washington

Drought Monitoring:  An Evaluation of Drought Indicators Based on Climate and Hydrologic Variables

Declining snowpack in Western United States is an issue of concern to water and energy managers.  While these downward trends are influenced on some level by interannual and decadal climate variability, the main attribution of the changes is to warming temperature trends over longer time scales.  Warmer winter and spring temperatures result in less snowfall and shift snowmelt onset to earlier in the year.  This shift leads to reduced summer streamflow when water demand is in many regions at its seasonal peak.  The snowpack decline and shifts in snowmelt timing have the potential to increase the severity, frequency and duration of drought, with negative implications for water resources in areas that are heavily dependent on snowmelt runoff, such as Washington State.  Timely determination of the current level of drought is essential for the adequate water management and planning. The most widely used drought indicator, the Palmer drought severity index (PDSI), does not keep account of the water stored in the form of snow, thus its applicability for drought monitoring in Washington state is questionable.  We describe the performance of several drought indicators that make use of land surface moisture fields from the Variable Infiltration Capacity (VIC) macroscale hydrological model.  VIC is a physically based model that takes account of process like snow  accumulation and melt and is conceptually better suited to depicting drought severity in hydrologic settings in which the role of snowpack is changing.  A second advantage of the model-based indicators are their finer spatial and temporal resolution, relative to the operational PDSI, which is calculated for climate division spatial units.  We evaluate the PDSI and model-based indices with respect to observed streamflow and drought declaration records, and argue that model-based indices are a potentially viable tool in characterizing drought severity in snowmelt-driven hydroclimate regimes.

Rei Ueyama   

Atmospheric Sciences, University Of Washington

Annular Nonseasonal Variability of the Winds in the Tropical Troposphere

Annular (zonally-symmetric), nonseasonal (departures from the seasonally-varying climatology) variability of the tropical tropospheric wind field is investigated, making use of data from the NCEP Reanalyses for the period of record 1979 through 2001, processed in the form of 5-day (pentadal) means. The variability of the zonally-averaged zonal wind [u] is dominated by the equatorially-symmetric (even) component. Bands of anomalies of a given polarity develop over the equator, widen, and split into northern and southern bands that propagate poleward within their respective hemispheres. The dominant mode of variability of the mean meridional circulations (MMC) consists of a single cell straddling and symmetric about the equator. The fluctuations in [u] and [v] are in forced by temporal variations in the poleward eddy flux of zonal momentum at ~35° latitude. The forcing from the Northern and Southern Hemispheres is asynchronous, but the tropical MMC are more effective at counteracting the odd component: hence the tendency for equatorial symmetry.

Sally Warner and Parker MacCready

Oceanography, University of Washington

A Numerical Investigation of Tidal Energy Dissipation Due to Flow over Rough Topography within an Estuary

Tidal flow over topography in estuaries and coastal regions has been identified as a key mechanism for mixing stratified water and dissipating the ocean's energy.  When currents and topography interact, the amount of barotropic tidal energy that is converted to baroclinic features such as internal waves or directly dissipated depends not only on the size and shape of the topography, but also the depth of the water-column above the topography. In order to explore this relationship between topography, tidal flow, and energy dissipation, a series of numerical experiments were performed using ROMS, the Regional Ocean Modeling System. The goal of these numerical experiments was to calculate drag coefficients that can be used in larger scale models to more accurately parameterize mixing and dissipation in coastal regions and estuaries. The work may also help predict changes in estuaries that will occur due to rising sea level brought on by climate change.

Qiong Yang1, Qiang Fu1, Andrew Gettelman2, Feng Li3, John Austin3, & Holger Vömel4

1Atmospheric Sciences, University of Washington, 2NCAR

3NOAA GFDL/ Princeton University, 4CIRES, University of Colorado

Analysis of Tropical Stratospheric Upward Mass Fluxes: A Comparison of Models and Observations

We quantify the vertical velocity and upward mass flux of Brewer-Dobson circulation (BDC) in the tropical lower stratosphere based on accurate radiative heating rate calculations using eight-year SHADOZ balloon-borne measurements of temperature, ozone and water vapor in the tropics (-20S—10N). The cloud distribution from the ISCCP is utilized to examine the cloud forcing on tropical upwelling of BDC. We find a constant vertical upward mass flux with a magnitude of ~ 1.03day form 19 km to 30 km, which is consistent with the idea that BDC is driven by wave breaking in the extratropics. A strong seasonal cycle exists in both vertical velocity and upward mass flux of BDC, with a maximum in boreal winter but a minimum in boreal summer. The upward mass fluxes also show a large inter-annual variation, exhibiting an increasing trend.  We compare the vertical mass fluxes from the NCAR and GFDL GCMs with those based on observational analysis in terms of annual mean, seasonal variation, and inter-annual variations.

Reddy Yatavelli and Joel Thornton

Atmospheric Sciences, University of Washington

Aerosol Organic Matter: Improving Our Understanding with Chemical Ionization Mass Spectrometry

Organic compounds are important constituents of fine particulate matter (≤ 2.5 μm), contributing 30 – 60% of the aerosol mass depending on the location and season, and up to 80% in forested regions. They can affect the water content of aerosols which has implications for visibility, cloud formation, and climate. Oxidation of organic aerosols can be a potentially large source of volatile oxygenated hydrocarbons, and thus affect photochemistry, in the troposphere and can also have significant impact on human health. Understanding the sources of aerosol organic matter, its chemical transformations and effects on the physical and chemical properties of the aerosols is important for climate and air quality. But, significant uncertainties related to sources and removal processes persist due, in part, to a poor understanding of the species which make up organic matter. Fast, in-situ, and speciated measurements are needed to elucidate chemical and physical mechanisms controlling the sources and sinks of aerosol organics. We are currently developing a novel technique called Micro Orifice Volatilization Impaction – Chemical Ionization Mass Spectrometry (MOVI-CIMS) to begin addressing these issues. This technique will be coupled to a flow reactor in the lab and later to a smog chamber at Pacific Northwest National Lab (PNNL) for in-situ measurements. Realistic parameterizations of organic aerosol evolution are needed to connect satellite-based sensing of aerosol optical properties to emissions of anthropogenic and biogenic aerosol precursors and to improve our global climate and chemistry models.

Xuebin Zhang1 & Michael J. McPhaden2

1Oceanography, University of Washington, 2NOAA/Pacific Marine Environmental Laboratory

Effects of Local Dynamical and Thermodynamical Forcings on Interannual Sea Surface Temperature

This research uses ocean general circulation model to examine the relationship between local wind stress, net heat flux and sea surface temperature variations on interannual time scale in the eastern equatorial Pacific. Effects of local dynamical forcing (wind stress) and thermodynamical forcing (heat flux) can be examined by comparing outputs from control run with full forcings and masked runs without either dynamical or thermodynamical forcings in the eastern Pacific. Local dynamical forcing provides mechanisms to make ENSO warm events stronger and last longer, especially during major ENSO warm events. Local thermodynamical forcing acts as a negative feedback to damp interannual SST anomalies generated by dynamical processes.