Academic Year 2015-2016

 Marine Cycling of Particulate Trace Metals Along the Rapidly Warming Western Antarctic Peninsula

The western Antarctic Peninsula (WAP) is the fastest warming region in the southern hemisphere, and an intensely productive marine system. In contrast to low-productivity offshore waters, shelf waters are rich in iron (Fe), an essential micronutrient for phytoplankton. Fe can be supplied by dust, sea ice, upwelling of waters enriched by interaction with shelf sediments, land runoff, and glacial processes. Many of these are changing as a result of warming. We present three years of particulate trace metal data from surface waters of the Palmer Long Term Ecological Research program, to investigate the sources, cycling and removal of particulate Fe and other biologically active trace elements in this region. Particulate metals show significant enrichment at the coast, consistent with a shallow sediment or glacier/snow runoff source. However, typically lithogenically-sourced elements suggest a greater influence of authigenic and/or biogenic phases than in many other marine provinces. In some areas particulate Fe was very low, similar to open ocean concentrations. Other bioactive trace metals linked to Fe nutrition further suggest Fe limitation in northern outer shelf stations, both on and off the shelf. The interactions between sea-ice cover, mixing supplying Fe from below, glacial inputs, and related impacts of biological uptake will determine the direction and magnitude of changes in the WAP Fe budget as climate change progresses.

 Spatial Analysis of Emerald Ash Borer (EAB) Spread in New Jersey

Emerald Ash Borer (Agrilus planipennis Fairmaireis), is an exotic invasive beetle that affects all species of true ash trees (Fraxinus species) in New Jersey. EAB was first detected in New Jersey during summer 2014. Maximum entropy modeling (Maxent) is utilized with presence-only data to estimate the probability distribution of EAB in New Jersey. This approach is data driven incorporating location specific characteristics. Maximum entropy method estimates the influence of spatial predictors on EAB spread. Relative importance of spatial predictors for EAB presence in New Jersey is evaluated. The model results provide key insights to inform municipalities regarding potential risk factors of EAB spread in New Jersey.

Time for a Change: Temporal and Environmental Dimensions of Variable Sex Expression in Striped Maple, Acer pensylvanicum (Sapindaceae)

Gender in plants is usually a fixed trait, however in rare cases, a plant may change sex expression during its lifetime. Using striped maple (Acer pensylvanicum; Sapindaceae), I investigated the distribution of gender and gender change in this sexually plastic species. The most common pattern was to express the same gender in both years; 75% of all trees did not change sex. While 85% of all males remained male in the second year, only 40% of ambisexual trees remained ambisexual. Among trees changing sex expression, the most common transitions were from male to ambisexual (31%) and male to female (16%). Non-reproductive trees that reached sexual maturity changed exclusively to male. Of trees dying of natural causes, 70% were female before dying. Preliminary data indicate that general tree health, recency, and severity of physical damage correlate with changes of sex expression in striped maple. Pilot forced flowering studies indicate that the final sex of a flower is determined within one month of flowering, with early flowers more frequently expressing female gender. This shows that striped maple may remain receptive to environmental sex-determining cues through early spring, and that early onset of warmer temperatures may have implications for population sex ratios.

Allowances for Evolving Coastal Flood Risk Under Uncertain Local Sea-level Rise

Sea-level rise (SLR) causes estimates of flood risk made under the assumption of stationary mean sea level to be biased low. However, adjustments to flood return levels made assuming fixed increases of sea level are also inaccurate when applied to sea level that is rising over time at an uncertain rate. To accommodate the temporal dynamics of SLR and their uncertainty, we develop an Average Annual Design Life Level (AADLL) metric and associated Design Life SLR (DL-SLR) allowances [1,2]. The AADLL is the flood level corresponding to a time-integrated annual expected probability of occurrence under uncertainty over the design life of an asset; DL-SLR allowances are the adjustment from 2000 levels that maintain current average risk over the design life. Given non-stationary and uncertain sea-level rise, AADLL flood levels and DL-SLR allowances provide estimates of flood protection heights and offsets for different planning horizons and different levels of confidence in SLR projections in coastal areas. Here we employ probabilistic sea-level rise projections [3] to illustrate the calculation of these metrics for a set of long-duration tide gauges along U.S. coastlines. [1] Rootzen et al., 2014, Water Resources Research. [2] Hunter, 2013, Ocean Engineering. [3] Kopp et al., 2014, Earth’s Future.

Arctic Sea Ice Reemergence Mechanisms in a Model Hierarchy

Lagged correlation analysis of Arctic sea ice area anomalies reveals that melt season sea ice anomalies tend to recur the following growth season, and growth season anomalies tend to recur the following melt season. In this work, the regional and temporal characteristics of this phenomenon, termed sea-ice reemergence, are investigated in a hierarchy of climate models. Coupled nonlinear Laplacian spectral analysis (NLSA), a multivariate data analysis technique, is used to study the covariability of Arctic sea-ice concentration (SIC), sea-surface temperature (SST), sea-level pressure (SLP), and sea-ice thickness (SIT). Two mechanisms related to melt season to growth season reemergence are identified: (1) An SST-SIC mechanism, related to local imprinting and persistence of SST anomalies in the seasonal ice zones, and (2) an SLP-SIC mechanism, related to winter-to-winter regime persistence of large-scale SLP teleconnection patterns. An SIT-SIC growth season to melt season reemergence mechanism is also identified, related to winter persistence of SIT anomalies in the central Arctic. The representation of these mechanisms is investigated using the model hierarchy to determine the relative roles of the ocean, atmosphere, and sea ice itself in producing reemergence. It is found that the SST-based and SIT-based mechanisms can exist as stand-alone processes, whereas the SLP mechanism cannot. Dynamical feedback from the ocean to the atmosphere is found to be essential in creating large-scale organized patterns of SIC-SLP covariability. A set of reemergence metrics is introduced, by which one can judge the amplitude and phase of reemergence events and associated mechanisms.

 Climate Change Response Framework

Land managers face the immense challenge of integrating the uncertainties of a changing climate into decisions that span large spatial and temporal scales. The Climate Change Response Framework is a collaborative, cross-boundary approach among scientists, managers, and landowners to incorporate climate change considerations into natural resource management. The Framework delivers credible, relevant information to land managers and provides a process to apply that information at multiple scales through (1) Partnerships that engage a variety of land managers and scientists; (2) Vulnerability assessments that synthesize projected changes in climate and impacts on forest ecosystems in order to provide critical information ecosystem vulnerability to climate change; (3) the Forest Adaptation Resources document which provides a suite of information to help natural resource managers integrate climate change information into land management planning and decisionmaking; and (4) Adaptation Demonstrations which are real-world examples of using the resources described above to demonstrate how managers have integrated climate considerations into planning and activities. These projects grow partnerships, test new ideas, and implement adaptation actions. We are currently building partnerships and developing a vulnerability assessment for the Mid-Atlantic Region. This document will serve as a baseline of information for future adaptation demonstrations, trainings, and outreach.

The Role of Mixed Layer Depth in Regulating Primary Production at Palmer Deep Canyon (West Antarctic Peninsula)

Palmer Deep Canyon in the West Antarctic Peninsula (WAP) is considered a biological “hotspot” by providing predictable food resource and driving penguin foraging locations. However, the physiology and composition of the phytoplankton blooms as well as the physical mechanisms driving them aren’t well understood. The aim of this study is to characterize the dynamics of the spring phytoplankton bloom over Palmer Deep Canyon. Here, a 5-year record of slocum glider deployments is analyzed. The depth of the mixed layer (MLD) was determined (using the maximum of the buoyancy frequency as the criteria), and its biological implications evaluated. In most glider profiles, the lower boundary of the chlorophyll concentration profile appears to be well correlated with the depth of the ML. The shoaling of the MLD in early January results in increased production, as evaluated by increased chlorophyll a concentrations. MLD deepens in early February, where a decreased in phytoplankton concentration is seen, likely due to decreased light availability. Throughout the season, the MLD gets, in average, warmer and saltier.

A Long-term Context (931e-2005 C.E.) for Rapid Warming In Mongolia & An Introduction to a New Climate Proxy

Our understanding of long-term temperature variability and its causes is limited in remote Central Asia, due to sparse meteorological data, as well as a paucity of long-term, high-resolution, temperature-sensitive proxy records. Instrumental records, reaching back to the 1940s, show that temperatures have been increasing rapidly, particularly since the mid 1990’s, and are currently warmer then at any other time in recorded history. We develop a millennium-length tree-ring width chronology from larch trees growing at elevational-treeline sites in Mongolia, where the dominant limiting factor for growth is temperature. The chronology and reconstruction can be calibrated and validated using regionalized meteorological data. The reconstruction allows us to evaluate variability and extremes over the past millennium in Central Asia, a region that is warming faster then many places on Earth. It also places recent warming trends into a long-term context, contributes to our understanding of the MCA and the LIA across Asia, and provides evidence of significant volcanic impacts. We also present preliminary results from novel Blue Light Intensity methods that demonstrate that blue intensity reflectance significantly improves the climate signal of temperature sensitive chronologies and will lead to additional millennial-length reconstructions from several sites that were not previously possible using ring-width alone.

 The Role of Discounting, Inequality Aversion, and Catastrophes in Motivating Strong Climate Change Mitigation: An Inequality-Alert Perspective

Integrated assessment models (IAMs) of climate and the economy provide estimates of the social cost of carbon and inform climate policy. We have developed the NICE model, a variant of the RICE model {a regionally disaggregated version of DICE} to explore the effect of several key parameters on optimal carbon price. Work in press has shown that the distribution of climate damages across income quintiles within regions has an important impact on the optimal carbon price. In this study, we further expand the development of NICE to consider the effects on optimal carbon price of the utility discount rate, the inequality aversion, and the potential role of a climate catastrophe. We find that as aversion to inequality increases, the distribution of climate related damages between different parts of the income distribution has a larger impact on the optimal carbon price. While valuing future generations more generally leads to more aggressive carbon taxation, this change also depends on the inequality aversion and the economic distribution of climate damages. Finally, the possibility of a "climate catastrophe" at 4 to 6C above pre-industrial average temperature is shown to effect policy most strongly when the distribution of climate damages is proportional to income.

Catherine Dillon, Allyson Salisbury, Frank Gallagher, Jason Grabosky

Comparing the leaf Area Index (LAI) of an Urban Forest Before and After Hurricane Sandy

Adequate knowledge of the costs and benefits of trees in urban environments helps to assess environmental damages caused by climate change, urban expansion and anthropogenic pollution. In addition to changes in seasonal average temperature and precipitation, more frequent extreme weather events such as hurricanes associated with climate change pose a significant threat to urban forests. Photosynthetic tissues making up the tree canopy generate life supporting ecological services are susceptible to environmental stresses. Leaf Area Index (LAI) for broadleaf canopies is a dimensionless unit defined as one half of the total leaf surface area per unit of ground surface area. Temporal and spatial comparison of LAI in canopies of the same species offers a quantitative method for comparing assemblage productivity in response to changing soil and climate conditions. This study tests the hypothesis that canopies of broadleaf species in soils with high heavy metal concentrations will have decreased LAI values when compared to their low metal load counterparts. It also tests the hypothesis that canopies in high metal load soils will exhibit lower regeneration rates after flooding caused by Hurricane Sandy. Measurements were collected over the course of the growing season in 2010, 2011, 2012, 2013, and 2015.

 Religious Beliefs a Root Cause of the Denial of Climate Change Being Anthropogenic

Denial of climate change being caused by human activity, or anthropogenic climate change, is thought to be divided between political lines with Republicans generally denying climate change while Democrats believing that climate change not only exists but is caused, at least in part, by humans. There appears to be a correlation between being religious and being a climate change denier. According to a Pew Research poll, 47 percent of Catholics acknowledge that climate change is anthropogenic, with 62 percent of Catholic Democrats but only 24 percent of Catholic Republicans believing in the anthropogeneity of climate change. The source of this denial may be that the deniers believe that that man is all that is to be valued. Imago Dei, the predominant intrinsic value system of religious monotheists, excludes non-humans, leading to neglect of the environment, even if it is closely tied to human beings. We have examined further this relationship between religion, the imago dei intrinsic value system, and anthropogenic climate change. Converting anthropogenic climate change deniers may be a matter of including the environment as being inseparable from human life, so that those that hold imago dei close, can now start taking care of the world they live in.

 Food Waste to Energy:The Intersection of Climate Change Mitigation,Sustainable Development and Resiliency

In 2015, New Jersey’s potential quantities of bio-based feedstock resources, clean energy generation and GHG emissions reduction were estimated. Analysis determined that the amount of food waste generated annually in New Jersey is approximately 704,612 tons. The research found that if food waste generated in the state was efficiently converted into low-carbon energy, NJ could potentially generate an additional 310,000 MWh low-carbon electricity and avoid 370,000 tCO2 /y. However, achieving this potential may be difficult under current practices. Currently, organics are mainly mixed with other constituents of MSW and decompose in the landfills, creating landfill gas (LFG) which is approximately 55% CH4,45 % CO2. LFG collection efficiency is highly debated and research suggests that modeled collection efficiencies are consistently higher than those calculated from field measurements (by 20% on average). Converting source separted food waste and organic waste in a closed Anaerobic Digestion (AD) system can reduce potential CH4 leakages and help mitigate climate change by displacing fossil fuel counterparts. AD systems can generate low carbon energy and biobased products, and the digestate, byproduct of AD, can be used as fertilizer to displace petroleum based fertilizers. Further, succesful AD applications can support opportunities for sustainable development and resiliency for communities.

 Killing the Goose...Antarctic Tourism and Climate Change

Tourism to Antarctica has increased steadily in this century (apart from a decline during the recession) with over 37,000 visitors in the 2013-4 season. While these numbers are small compared to most tourist destinations, the Antarctic (with no permanent residents) is one of the environments most vulnerable to human impacts. Tourists to Antarctica typically travel thousands of miles by air (the U.S. and Germany are the two largest "sending" countries) before sailing from Argentina to the Antartic Peninsula or from Australia to East coast bases. Emissions from this travel contribute to global warming. While visitors who set foot on the continent (by no means all) they do so during the most high-impact time for the environment when wildlife is reproducing. New tourist activities - skydiving, scuba, paragliding, waterskiing, snowmobiling, cycling - can have heavy environmental costs. Habitats are trampled, exotic species introduced, and oil spilled. The counter-argument is that such tourists can be ambassadors for saving the Antarctic environment. Rather than killing the goose which laid the golden egg in Aesop's fable, upscale Antartic tourists could perhaps be encouraged to spend their resources on preservation rather than "adventure."

The JCNERR Tuckerton Peninsula Salt Marsh System: Development of a Sentinel Site for Long-Term Climate Change Research

The Tuckerton Peninsula is the designated sentinel site of the Jacques Cousteau National Estuarine Research Reserve (JCNERR) for the detection, monitoring, and research of climate change effects, most notably sea-level rise, inundation, marsh-edge erosion, and habitat loss. This 2000-ha Spartina salt marsh platform in southern New Jersey is dissected by expanding channel networks and pond development. Loss of marsh habitat area has accelerated due to extreme weather events, storm surge, perimeter shoreline erosion, sea-level rise, and submergence. Sentinel site infrastructure is being installed (i.e., surface elevation tables, tidal stations, and benchmarks) to assess climate change effects. The long-term goal is to document changes in accretion rates, marsh surface elevation, and conversion to intertidal/subtidal habitat with ongoing sea-level rise and coastal subsidence. In addition, biomonitoring surveys, marsh elevation and emergent vegetation mapping, and vegetation health metrics acquisition are ongoing to characterize vital spatio-temporal changes in the system. Together, current and future projects will leverage our understanding of climate change impacts on the peninsula and will help coastal managers plan effective adaptation strategies for future loss of this extensive marsh platform that currently buffers human settlement from extreme weather-related events and inundation associated with rising sea level.

Climate Change Impact on Photochemical Air Quality, Human Exposures, and Cardiovascular Health

BACKGROUND: Climate change is impacting air quality at regional and local scales, as it affects biogenic and anthropogenic emissions and dynamics of atmospheric transport and photochemistry. Indoor air quality is affected as a result of ambient air changes and modifications of human behavior and building dynamics. People, especially susceptible groups (e.g. the elderly), spend most of their time indoors. Since air pollution impacts cardiovascular health, it is important to understand how associated exposures can be controlled under conditions of climate change. METHODS: An interdisciplinary team at EOHSI has commenced a USEPA-funded project studying the effects of climate change on air quality, focusing on outdoor/indoor ozone, and on associated cardiovascular effects within the elderly. The project combines environmental and biological modeling across multiple scales in conjunction with field measurements of air quality (with/without air cleaners) and pulmonary oxidative stress biomarkers (indicators of increased risk). Coordinated environmental/biological measurements are taking place at two locations in distinct US climatic regions (New Brunswick, NJ, and Atlanta, GA). A modeling system employing an enhanced version of CMAQ (Community Multiscale Air Quality Model), coupled with a new indoor chemistry model, links alternative climate change scenarios with regional, local, and indoor photochemical air quality and human exposures.

 Changing Arctics—The Tourist Gaze

In preparation for research in Arctic regions, we signed up for a commercial tourist expedition with the company Adventure Canada, August 8-21, 2015. The trip reinforced and deepened our knowledge about the high Arctic, which was otherwise based on reading, the media, and our imaginations. We here present a verbal and graphic outline of the trip, with particular emphasis on what we saw, experienced and learned about climate change in the Eastern Canadian Arctic and the northwestern Greenland Arctic. We title this “Changing Arctics, ” using the plural to indicate the importance of focusing on particular places and systems of the far north rather than depicting “the Arctic” as a whole. The happy—and sad—fact of a very warm summer and little sea ice made for an easy voyage but also disappointing and disturbing encounters with wildlife. The lack of sea ice on our itinerary meant seeing few polar bears and seals, at least up close, and seemed to underscore the widely-discussed problem of declining polar bears due to climate warming. However, we learned that in much of the region we visited polar bears are not thought to be declining in numbers, in contrast to their fate in other parts of the Arctic. The lack of sea ice also became part of a disturbing story we learned about thick-billed murres and a shift in the major forage fish, from Arctic cod to capelin. Then we found, when our itinerary was drastically changed, that there was a lot of sea ice, just in the wrong places, forcing us to leave Baffin Island and go to Greenland earlier than planned. Finally, we encountered fishing villages and Inuit populations of Greenland’s northwest region, and though we were tempted to think of them as victims of climate change, experiencing as they have major changes in their cold environment, we came to appreciate their adaptability and flexibility. These and other encounters led us to appreciate the need to avoid over-generalizing about “polar bears,” “Inuit” and “the Arctic,” and instead to discern differences as well as similarities in experiences of and responses to climate change.

Polar Interdisciplinary Coordinated Education (ICE): A Program Designed to Connect Scientists, Educators, and Students Using Data and Research from the Arctic and Antarctic Regions.

The Polar ICE team is a group of educators and scientists working together to share scientific research from the Arctic and Antarctica with middle school students. We partner both with scientists to communicate their science beyond their colleagues and academic peers, and collaborate with educators to bring polar science to the classroom highlighting the science research practices. This NSF funded project has three main objectives: 1) Build capacity of polar scientists to communicate with diverse audiences. Polar ICE will partner with approximately sixty polar scientists, including late-stage graduate students, post doctoral researchers, and principal investigators, to develop and apply science communication skills. 2) Create opportunities for educators and students to engage with polar scientists and their research. Polar ICE will offer a variety of professional development programs for middle and high school educators and students interested in virtually joining polar science missions. 3) Evaluate Polar ICE and contribute to our broader understanding of science education practices. Polar ICE will explore the evidence of student engagement in data-focused classroom activities, and their ability to access a personal identity as a scientist. Our evaluation program will include surveys of both educators and scientist collaborators.

Longitudinal Inter-comparison of Modeled and Measured West Greenland Ice Sheet Meltwater Runoff Losses (2004-2014)

Increased surface meltwater runoff, that exits the Greenland ice sheet (GrIS) margin via supra-, en-, and sub-glacial drainage networks into fjords, pro-glacial lakes and rivers, accounts for half or more of total mass loss. Despite its importance, modeled meltwater runoff fluxes are poorly constrained, primarily due to a lack of direct in situ observations. Here, we present the first ever longitudinal inter-comparison of a multi-year dataset (2004-2014) of discharge for four drainage basins – Watson, Akuliarusiarsuup Kuua, Naujat Kuat, and North Rivers - along West Greenland. These in situ hydrologic measurements are compared with modeled runoff output from Modèle Atmosphérique Régional (MAR) regional climate model, and the performance of the model is examined. An analysis of the relationship between modeled and actual ice sheet runoff patterns is assessed, and provides insight into the model’s skill to capture inter-annual and intra-annual variability, spatiotemporal patterns, and extreme melt events. This study’s findings will inform future development and parameterization of ice sheet surface mass balance models.

 The Clickable Histogram (ClickHist) – A New Tool for Sifting Through Big Data in the Earth Sciences

For years, Earth scientists have needed to make do with the sparse, often limiting, and ultimately disappointing availability of observations. Conversely, freely available output from state of the art climate models is now reaching unwieldy sizes, forcing the introduction of petabytes (thousands of terabytes) into the climate science vernacular. There currently exists a gap in Earth science between traditional analysis techniques and tools equipped to handle (or even to sift through) the massive amounts of data currently available. One solution that can fill that gap is the Clickable Histogram (ClickHist), freely available software that enables not only an interactive exploration of Earth science data but adds additional, customized functionality to guide the user from data extrema toward useful case study visualizations. As one example of the power of ClickHist, an implementation known as the Clickable Histogram of Atmospheric Data, or CHAD, will be presented that creates downloadable bundles of manageable size (hundreds of megabytes) for use in Unidata’s Integrated Data Viewer (IDV). ClickHist has transformative potential by spurring undergraduate research projects earlier in students’ studies, particularly if they would have been otherwise excluded due to a lack of prior programming experience.

 Coastal Ocean Primary Production Sensitivities to Extreme Melting of the Greenland Ice Sheet

Responding to the July 2012 extreme melting of the Greenland Ice Sheet, this study investigates how marine primary productivity of the region may be affected by changes resulting from increasing meltwater discharge. Meltwater delivered to the ocean may increase stratification in coastal waters, which is often beneficial to the light-limited phytoplankton typically found in polar regions. However, plumes of buoyant meltwater may also increase nutrient limitation by isolating the phytoplankton from deep nitrogen supplies. To characterize these responses to melt in the coastal ocean west of Greenland, we created a light-influenced marine ecosystem model using Regional Ocean Modeling System (ROMS) model output generated as a part of a larger interdisciplinary Ice Sheet Impact Study. The ROMS produced ocean output for two cases over a ten-year period: with and without meltwater runoff. Using these two cases, we determined the perturbation in mixed layer depth, light availability, and the expected phytoplankton growth rates, due to meltwater over different regions and melting conditions. The sensitivity results indicate a decrease of mixed layer depths with increasing meltwater input, and that the increased light availability caused by greater melting allows for increased primary production, especially in late summer.

Application of Self-organizing Maps to Observed and Simulated Daily Precipitation over the Tropical and Southern Pacific Ocean

Self-organizing maps (SOMs) comprise a class of artificial neural networks that aim to organize complex input data through computation of a set of M x N representative maps. Here we use an SOM routine to isolate the spatial patterns inherent in daily austral summer (December-January-February or DJF) rainfall over the tropical and southern Pacific Ocean basins from Tropical Rainfall Measuring Mission (TRMM) satellite observations as well from an ensemble of models from Phase 5 of the Coupled Model Intercomparison Project (CMIP5). Computing a 2x2 SOM from all available DJFs from 15 years (1998-2013) of TRMM data yields two maps that may be regarded as Intertropical Convergence Zone (ITCZ)-active, in which precipitation is more intense over the ITCZ region compared to the South Pacific Convergence Zone (SPCZ) region, while the remaining maps are SPCZ-dominant. The latter reflect a spatial translation of the principal SPCZ diagonal consistent with the impacts of the El Niño/Southern Oscillation (ENSO) or analogous low-frequency modes of variability on the SPCZ as shown in prior studies. Comparing the CMIP5-based SOMs to TRMM reveals some broad similarities in the orientation and extent of large-scale features, as well as spurious features like the spurious Southern Hemisphere ITCZ in the Eastern Pacific, which underscore errors or biases present in the models. Because of the pronounced impact of ENSO, we further consider SOMs computed separately for each of the El Niño and La Niña phases. While the overall position of the SPCZ is sensitive to the phase of ENSO, within each phase, similar configurations of the slope of the SPCZ diagonal occur. Thus, while the mean position of the SPCZ may be dominantly controlled by ENSO phase, the distinct orientations within the same ENSO phase point to higher-frequency modulation of SPCZ slope. To investigate these controls further, we construct composites of pressure-level winds and specific humidity from the Climate Forecast System Reanalysis product based on the assignment of days to each SOM. These composites show large-scale features in wind and humidity that are consistent with the rainfall maps and which we interpret in terms of previously described mechanisms of SPCZ variability.

Greenland Ice Sheet Meltwater Export and River Discharge

The Greenland ice sheet supplies massive amounts of freshwater and sediments to surrounding oceans, contributing to global sea level rise and influencing marine ecosystems. A large portion of this meltwater runoff flows through rivers draining the entire perimeter of the ice sheet. These unique river systems are characterized by strong seasonality, high sediment loads due to glacial erosion, and variable basin size and hypsometry over a melt season, during which the melting front propagates upwards and engages an increasingly larger drainage basin area. Other sources of Greenland streamflow include runoff from tundra areas, peripheral glaciers and ice caps. Despite the uniqueness and importance of Greenland surface streams, a comprehensive, comparative study of these systems has not been made. Here, we present an investigation of these systems and analyze their role in the total Greenland meltwater export to the ocean. River catchment areas are identified by analyzing high-resolution digital elevation models of ice sheet surface topography. Discharge from individual rivers are derived from the regional surface mass balance model Modèle Atmosphérique Régional (MAR). Our inventory of Greenland Rivers’ hydrological regime, characteristics, and emerging trends provides insights into the current and future state of Greenland streamflow.

 The Effects of Heavy Metal Exposure and Drought on the Photosynthesis of Mature Gray Birch and Quaking Aspen

The interacting effects of heavy metal contaminated soil and drought on the photosynthesis of Betula populifolia (gray birch) and Populus tremuloides (quaking aspen) were studied in the summer of 2015. Climate change predictions suggest North America will experience more intense droughts, frequent heat events, and extreme precipitation. In the urban environment predictions about the effects of climate change – particularly changing hydrologic patterns – on plant growth may be complicated by pollution from both current and historic sources. The interaction between heavy metals contamination and plant water relations during drought is complex. Side effects of heavy metal exposure appears to confer drought tolerance in some species but not in others. The study tests the hypothesis that photosynthetic and transpiration rates of mature gray birch and quaking aspen growing in high metal load (HML) soils will be less affected by a short heat wave and drought followed by a month of below average precipitation compared to the low metal load (LML) plots. Photosynthesis and transpiration were measured monthly from May 2015 to September 2015 using a portable gas exchange analyzer. Measurements were made in trees from two LML plots and two HML forested plots in Liberty State Park, Jersey City, New Jersey.

 Arctic Melt: Native Voices on the Dilemmas of Development

This film, based on field research conducted in the Arctic, presents interviews with Alaska Arctic Natives on the dilemmas of offshore and expanded oil exploration and the risk to their subsistence harvesting and communities. New sea ice minimums and a longer open water season have led to oil company and other industry plans for on- and off-shore development (Shell’s recent retreat is likely short term and other “outsider-driven” development is still proceeding). Oil development has provided the means for social and economic development in the arctic but recent declines in North Slope production significantly reduce revenue for these communities; however, expanded marine and terrestrial development, made possible by sea ice declines, is also a challenge to community sustainability. New infrastructure, population growth, and marine and terrestrial traffic pose threats to marine harvesting and large scale terrestrial development could have a “North Dakota Effect”, undermining community integrity and sustainability. This (rough cut) film short presents the different perspectives on these issues in Alaska North Slope communities.

Decadal Variability Phytoplankton Community Composition in the Coastal Waters of a Warming West Antarctic Peninsula.

The coastal waters of the West Antarctic Peninsula (WAP) are associated with large phytoplankton blooms dominated by large (20 microns) diatoms however, nanoplankton (20 microns) are also an important component in the phytoplankton community. Using a twenty-year time series collected by the Palmer Long Term Ecological Research (Pal LTER) program at the United States Palmer Research Station, we assessed long-term patterns and stability in the coastal phytoplankton communities in the WAP. There was significant interannual variability in the integrated water column chlorophyll a (chl-a) concentrations, which varied by a factor of 5 over the 20-year time series. Within the time series the dominant phytoplankton taxa were diatoms, with the second most abundant phytoplankton taxa present being cryptophyes. Peak biomass was observed in summer months mirroring declines in the seasonal monthly average wind speed. Cryptophytes were most abundant in the summer months of December and January after the seasonal retreat of sea ice. While diatoms were observed over the full range of observed salinities (34.5 to 32) as well as over the full range of in situ temperatures (-1.5 to 2.5° C), the cryptophyte populations were observed in lower salinity (33.75 to 32.5) and colder water (-1 to 1° C). Time series showed that during years when environmental factors favor water column stability, there are anomalously large summer diatom blooms that resulted in high krill recruitment, consistent with the classic Antarctic paradigm of a short diatom−krill−top predator food chain. In low phytoplankton biomass summers there was a recurrent shift to a larger proportion of the overall chl-a being present in cryptophytes. Consistent with modeling studies this suggests a potential shift to multivorous food web, which has significant ecological and biogeochemical implications, such as decreased efficiency of atmospheric carbon sequesteration.

 Investigating Common Era Sea-Level Changes, Chesapeake Bay, U.S. Atlantic Coast.

Proxy based relative sea-level (RSL) reconstructions extend our knowledge of sea-level history beyond the instrumental period and have helped identify spatial and temporal differences along the U.S. Atlantic Coast throughout the Common Era (CE). This paper presents a new RSL CE record utilizing foraminifera from microitdal (0.4m) salt marshes in the Chesapeake Bay region. An extensive stratigraphic survey of the salt marshes located at the Smithsonian Environmental Research Facility, MD, revealed thick sequences of organic salt-mash peat ideally suited for proxy based reconstructions from which a 6.1m core was selected for fossil foraminifera at high (1-5cm) resolution. Estimates of paleo marsh elevation were derived using a modern training set of 60+ surface samples and subtracted from surveyed altitude to provide sea-level index points constrained by a composite chronology combining 15 AMS radiocarbon dates with short-lived radionuclides (210Pb and 137Cs) within a Bayesian temporal framework. The reconstruction reveals sea-levels increasing ~1.6 mm/yr for much of the late Holocene before rates similar to that of observational period are recorded for the past 150 years.

 Synoptic-scale Patterns Associated with Flash Flooding in the Neversink River and Esopus Creek Watersheds in New York, USA

The rapid onset of flash floods make these events important in the Catskill Mountains, where flooding-related turbidity may degrade the quality of water contributed to the New York City water supply system. To increase understanding of flash flooding in the Catskills, synoptic-scale atmospheric conditions associated with these events were examined. Flash floods were identified using USGS 15-minute discharge data from the Esopus Creek and Neversink River gauges. Between 1987 and 2013, 25 flash floods were detected, occurring on 17 days. The discrepancies between the dates of National Weather Service flash flood warnings for the county encompassing the watersheds and the dates of detected flash floods demonstrate the localized nature of flash flooding in the Catskills. The synoptic-scale atmospheric patterns influencing the study area were characterized by a principal component analysis and k-means clustering of NCEP/NCAR 500 mb geopotential height reanalysis data. This procedure was executed in Spatial Synoptic Typer Tools 4.0. Seventeen unique patterns were identified; three were associated with flash floods. Composites of these flood types show a southwesterly flow suggesting advection of moisture from the Atlantic Ocean. This multi-scalar approach links flash flooding with synoptic-scale atmospheric circulation while also highlighting the heterogeneous flash flood regimes in mountain watersheds.

 Wintertime North Pacific Teleconnection Patterns: Seasonal and Interannual Variability

Atmospheric low-frequency anomalies, also known as teleconnec- tion patterns, are most energetic in the Northern Hemisphere dur- ing the winter season. These teleconnections have a far-reaching impact on weather and climate that spans the Northern Hemi- sphere. In this study, the teleconnections of the wintertime North Pacific are examined from the continuum perspective with self- organizing map (SOM) analysis. Using daily ERA-Interim reanal- ysis data for the 1979-2011 period, we found that most of the North Pacific teleconnections can be grouped into several Pacific/North America (PNA)-like, Western Pacific (WP)-like, and East Pacific (EP)-like SOM patterns. Each of the SOM patterns has an e- folding time scale of 7 to 10 days.The WP-like SOM patterns un- dergo a decline in their frequency from early to late winter, and vice versa for the EP-like SOM patterns, corresponding to an east- ward seasonal shift of the North Pacific teleconnections. It is shown that the interannual variability of the PNA, WP, and EP can be interpreted as arising from interannual changes in the frequency of the corresponding SOM patterns. The seasonal shift and inter- decadal trend of these teleconnections are found to be associated with corresponding changes in sea ice and precipitation.

Climate Change Impact on Allergenic Pollen Seasons in the United States

BACKGROUND: Many diseases are linked with climate trends and variations. In particular, climate change is expected to alter spatiotemporal dynamics of allergenic pollen from trees, weeds and grasses, and potentially increase occurrence of allergic airway disease. METHODS: Average changes of allergenic pollen season timing and levels were obtained using trend, correlation and geospatial analyses based on observed airborne pollen count, temperature and precipitation across the contiguous US (CONUS). RESULTS: The allergenic pollen seasons of birch (Betula), oak (Quercus), ragweed (Ambrosia), mugwort (Artemisia) and grass (Poaceae) between 2001-2010 across the CONUS have been observed to start 3.1 (95% CI:1.2-5.0) days earlier on average than in the 1990s (1994-2000). The average peak value and annual total of daily counted airborne pollen have increased by 38.3% (95% CI:19.9-56.7%) and 37.8% (95% CI:16.5-59.2%), respectively. So, allergenic pollen seasons across the CONUS on average have been starting earlier, accompanied with increasing airborne pollen levels, likely due to recent climate change. Changes of allergenic pollen seasons were more prominent at higher latitudes, where enhanced warming and precipitation have been occurring. Population exposures to allergenic pollen at earlier times and higher levels are likely to take place for populations at higher latitudes under changing climate conditions.