ITR: A Computational Framework for Observational Science: Data Assimilation Methods and their Application for Understanding North Atlantic Zooplankton Dynamics

This project will develop a modular data assimilation system, investigate several algorithms to make data assimilation more efficient, and will apply this system to investigate zooplankton dynamics in the North Atlantic. The goal of data assimilation is to find the value of the control variables (typically, the initial conditions or boundary conditions or model parameters) producing the best agreement between the model and the data. A data assimilation system consists of a forward model representing known dynamics. This model is integrated and the deviation between its predictions and available observations are quantified by a cost function. An adjoint model, representing the inverse of the known dynamics, is then run to determine the dependence of the cost function on the control variables. From the results of the adjoint model, the control variables are adjusted and the entire procedure repeats until the system converges on an answer. Because of the many iterations of the forward/adjoint system are required to find an answer, data assimilation is a computationally intensive process. The proposed data assimilation system will attempt to improve the effciency through parallelization and algorithmic improvements. Specifically, this project will evaluate three standard minimization algorithms and a new algorithm based on multigrid techniques. Using this system, data from the Continous Plankton Recorder survey, the only ongoing basin-wide plankton survey, will be assimilated to provide an accurate, quantitative description of the seasonal and interannual changes of North Atlantic zooplankton populations (especially, Calanus finmarchicus) in the Gulf of Maine and across the entire North Atlantic. This description will provide a better mechanistic understanding of the processes responsible for observed patterns in these populations. Such an understanding is prerequisite for predicting the impact of climate variability and change on zooplankton populations and the ecosystems they support.Broader Impacts: The proposed data assimilation system is a general model for many data assimilation problems including operational oceanography and numerical weather prediction. This project\u27s association with the Cornell Theory Center (CTC) allows a unique opportunity to share its data assimilation system to a wide audience. With the help of CTC staff, a web interface to the system running on CTC\u27s .NET cluster will be built. This interface will allow researchers and students across the world to access a high-performance data assimilation system. The development of the data assimilation system will be integrated into a series of computational tools courses offered at Cornell. This project will also provide research opportunities for both graduate students and undergraduates

Letter From Commander and Chief John J. Pershing to Major General Edward F. McGlauchlin, Jr., March 29, 1919

Letter from Commander and Chief John J. Pershing to Major General Edward F. McGlauchlin, Jr. dated March 29, 1919. It summerizes the First Divisions military service during the war.https://digitalmaine.com/foss_241503/1004/thumbnail.jp

Correspondence: WWI Letter Signed by John J. Pershing, France; March 26, 1919

Correspondence: WWI Letter Signed by John J. Pershing, France; March 26, 191

Collaborative Research: Life Histories of Species in the Genus Calanus in the North Atlantic and North Pacific Oceans and Responses to Climate Forcing

Species in the genus Calanus are predominant in the mesozooplankton of the North Atlantic and North Pacific Oceans. Their key role in marine food web interactions has been recognized in GLOBEC programs, both in the U.S. and internationally. Considerable knowledge of life history characteristics, including growth, reproduction, mortality, diapause behavior and demography has been acquired from both laboratory experiments and measurements at sea. This project reviews and synthesizes this knowledge and uses it to develop an Individual Based Life Cycle model for sibling species in two sympatric species pairs, C.marshallae and C. pacificus in the North Pacific Ocean and C. finmarchicus and C.helgolandicus in the North Atlantic, that have been the particular focus of GLOBEC programs and other recent research projects in the U.S., Canada and Europe. The IBLC model is then applied to make predictions about the life history response of each species to forcing under reasonable climate change scenarios for ambient food and temperature. The project involves training of a graduate student and two postdoctoral researchers in evaluation and prediction of effects of climate change on marine plankton populations. It fosters international collaboration with Canadian and European researchers, including participation in a workshop in Europe. Outreach to the broader fishing and management community is through seminars, information exchange sessions with fishermen managers, including the Maine Fisherman?s Forum, collaboration in affiliated projects with colleagues involved in herring and tuna research in the Gulf of Maine and in climate and fisheries interactions within NOAA

Collaborative Proposal: CAMEO: Using interdecadal comparisons to understand trade-offs between abundance and condition in fishery ecosystems

The investigators will conduct a model-based investigation of the dynamics of a productive pelagic ecosystems in the Gulf of Maine. The middle trophic levels in highly productive marine ecosystems are typically dominated by a few species of pelagic fish, such as sardines and anchovies in upwelling environments or herring and/or capelin in temperate and subpolar regions. These species act as important conduits for energy to higher trophic levels, including larger fish, seabirds, and cetaceans. When abundant, small pelagics can exert significant pressure on their prey, typically large mesozooplankton. Small pelagic fish exhibit complex dynamics and managing these species under an ecosystem approach is challenging. This modeling study will track both the abundance and condition of representative copepods (Calanus finmarchicus, Centropages typicus), herring, and bluefin tuna. The investigators will use a rigorous comparison of conditions from the 1980s and 1990s to develop the model. They will examine the sensitivity of this ecosystem to changes in fishing pressure on the middle trophic levels and to changes in the magnitude and timing of primary production. They will also consider the impact of increased temperature on the ability of C. finmarchicus to accumulate lipids and alter the condition of herring and tuna.The project will lead to improved knowledge of ecosystems with productive food webs. It will also directly impact address issues related to the management of the herring resource in the Gulf of Maine. The investigators will examine the consequences of ignoring condition of zooplankton and fish, as is the case with the current stock assessment. They will also explore the dynamical properties of the model ecosystem and consider under what conditions it is possible to have both abundant and well conditioned herring

Influence of fuel composition and flame temperature on the formation of thermal and fuel NOx in residual oil flames

Journal ArticleA 900 kw model package boiler and a 20 kw laboratory tunnel furnace were used to study fuel and thermal NO, formation during heavy oil combustion. Package boiler results indicated that atomizer design, spray/ flow field interactions, and fuel composition were significant, dependent parameters. These effects were then investigated in detail in the laboratory furnace. One distillate and nine heavy oils were studied. Fuel NO.,., isolated with an argon/oxygen/carbon dioxide oxidant, was found to be a major source of NOx emissions. Fuel NOx formation increased approximately linearily with increasing nitrogen content from 0.05 to 0.79 wt. percent nitrogen. Fuel nitrogen oxidation was insensitive to temperature changes (over the theoretical temperature range of 2100 to 2500°K) except for one oil which exhibited a sudden increase at the highest temperature. Fuel NOx was insensitive to drop size, but thermal NOx increased with decreased mean droplet size. Percentage conversion of bound nitrogen decreased with increasing nitrogen content except for one oil containing substantial refractory nitrogen. Doping studies indicated that fuel sulfur can enhance fuel NOx formation and that nitrogen and hydrocarbon volatility are not first order parameters with a rapid mix burner under fuel-lean conditions

Pulverized coal combustion: NOx formation mechanisms under fuel rich and staged combustion conditions

Journal ArticleA 2 Kg/h pulverized fuel one dimensional flame combustor was used to determine time resolved NO profiles under fuel rich and staged combustion conditions. Seven solid fuels, including two coal chars, were investigated. Results show that at all fuel rich conditions NO is formed rapidly and then is slowly destroyed

Control of NOx and particulate emissions from spreader-stokers fired with hogged wood

Journal ArticleThe formation and emission of nitrogen oxides and particulate carry-over were studied from spreader-stoker combustion of hogged Douglas-fir, with a focus on optimizing the combustion conditions in each of the two distinct combustion zones, the bed phase and the suspension phase local oxygen availability was the controlling parameter for nitric oxide formation. Minimum nitric oxide emissions were found when local air:fuel stoichiometric ratios were held at 0.70-0.85, with emissions reduced as much as 39%. Long first-stage residence times allowed intermediate nitrogenous species to decay to molecular nitrogen, if there was sufficient oxygen for first-stage formation of nitric oxide. Entrainment of large particulates was a function of furnace gas velocities in the bed zone. Operation of the furnace at low stoichiometric ratios (fuel rich) in the bed zone reduced these gas velocities and thus reduced particulate emissions

Understanding Copepod Life-history and Diversity Using a Next-generation Zooplankton Model

Evolution has shaped the physiology, life history, and behavior of a species to the physical conditions and to the communities of predators and prey within its range. Within a community, the number of species is determined by both physical properties such as temperature and biological properties like the magnitude and timing of primary productivity, and ecological interactions such as predation. Despite well-known correlations between diversity and properties such as temperature, the mechanisms that drive these correlations are not well-described, especially in the oceans. The investigators will conduct a model-based investigation of diversity patterns in marine ecosystems, focusing on calanoid copepods. Diversity changes on both sides of the Atlantic suggest three main hypotheses, relating copepod diversity to environmental stability, productivity, and size-based predation. To test these, the investigators will develop a novel model of copepod population dynamics. The model treats developmental stage and mass as continua, leading to a single partial differential equation for abundance as a function of stage and mass. This approach facilitates the use of algorithms from computational fluid mechanics to resolve numerical dispersion problems that characterize many copepod abundance models. This new modeling framework will be tested by building a model for the species Calanus finmarchicus and Pseudocalanus newmani to compare the results of the model with prior observations and models for two contrasting ecosystems, the Gulf of Maine and Gulf of St. Lawrence. The model formalizes trade-offs between temperature-dependent development, mass-dependent and temperature-dependent growth, and mass-dependent mortality. A series of 1-D simulations will be conducted, encompassing a range of environmental conditions. Each simulation will be initialized with many distinct species, where a species is described by a set of parameters specifying key physiological and life history parameters. These will be coupled to a nutrient-phytoplankton-microzooplankton model and integrated for many years. This procedure will produce a community of copepods adapted to conditions in each simulated environment. By studying how the modeled copepod communities respond to changes in physical conditions, productivity, and predation, mechanisms accounting for copepod diversity patterns will be tested.The project will lead to improved models for important copepod species that can be incorporated into ongoing and future ecosystem forecasts. The information on copepod biogeographic limits developed by this study could support estimates of copepod distributions under climate change. The model will be designed to work in a basin-scale model. By allowing adaption to physical and biological conditions, the emergent copepod communities should provide more realistic estimates of the impact of climate change. The project will support the professional development of one graduate student and one postdoctoral associate. It will also engage one undergraduate summer intern each year. Concepts related to this project will be communicated to the wider public on a blog at SeascapeModeling.org

CNH: Collaborative Research: Direct and Indirect Coupling of Fisheries Through Economic, Regulatory, Environmental, and Ecological Linkages

The productivity and resilience of fisheries are subject to a multitude of dynamic and interrelated influences that arise from complex coupling of fish populations with the natural and human systems of which they are a part. With few exceptions, fisheries currently are managed independently, ignoring important natural and human linkages among them. The biological productivity, sustainability, and consequently human benefits of complex fishery systems may be substantially increased if these linkages are better understood and if this understanding is applied to management. The American lobster (Homarus americanus), Atlantic herring (Clupea harengus) and Northeast multispecies groundfish fisheries in the Gulf of Maine are of major ecological, economic, social, and cultural importance to the New England region. They are subject to an array of natural and human linkages that have not yet been systematically studied. This interdisciplinary research project will examine key natural and human linkages among these fisheries and integrate them into a quantitative framework, using numerical modeling to explore how improved understanding of complexity can improve sustainability and increase the flow of human benefits. An important component of the research is the translation of concepts and results into an educational program that will teach a new generation of students about the human and natural complexity of the Gulf of Maine ecosystem and create a sustained interest in marine science. The research is organized by themes. Theme 1 focuses on management of the coupled fishery system. Numerical models will be used to integrate research undertaken in themes 2,3, and 4 and to explore how information regarding interrelated natural and human processes can be used to improve management of these resources. Theme 2 will use econometric estimation and bioeconomic modeling to investigate the human connections between these fisheries that arise through movement of labor and capital between fisheries, regulatory interventions and markets for inputs and outputs, such as herring used as an input to lobster harvest. Theme 3 will synthesize and analyze existing data to characterize variability in transport and survival of early life stages to identify exogenous processes (especially climate-related processes) that drive variability in recruitment. Theme 4 will combine new field studies with analysis of existing data to examine the impact of natural and human-induced trophic interactions among lobster, herring, and groundfish on the population dynamics of these species. Theme 5 will focus on translating research findings into an interactive marine science education program, based at the Gulf of Maine Research Institute, which serves fifth and sixth graders throughout the state of Maine.The project will make important contributions to science by improving basic understanding of the dynamic interrelationships of physical, ecological, and human-economic processes that determine the productivity and variability of the Gulf of Maine lobster, herring, and groundfish fisheries. It also will help develop concepts, research methodologies, and models relevant to fishery systems around the world. There is general agreement on the need to take an ecosystem approach to managing fisheries, but little concrete progress has been made in doing so. This project will develop concepts and methodologies needed to implement an ecosystem approach to fishery management. The project brings together a team of researchers from a broad range of disciplines and will demonstrate the benefits of an integrated interdisciplinary approach to investigating natural-human systems. The research will develop new understanding and approaches for management of important Northeast U.S. fisheries. The new information and insights will be conveyed to fishery managers through seminars, participation in the management process, and publications. The research will be coordinated with an ongoing, interactive marine education activity. A broader goal of that education program is to increase the number of students pursuing education and informed careers in the sciences by generating interest and excitement about science at a critical age. The project also will provide training for graduate students and undergraduate assistants in quantitative, multidisciplinary approaches to the study and management of coupled natural-human systems. This project is supported by an award resulting from the NSF competition focusing on the Dynamics of Coupled Natural and Human Systems