James G. Anderson - US grants

This grant is to provide statistical, computing and data management support for the Cancer and Acute Leukemia Group B (CALGB). These activities will involve collaboration in all appropriate activities associated with the planning, monitoring data collection and analysis of data obtained from clinical trials conducted by the CALGB. Research and development of statistical methodology and computer software aimed at more effective planning, data management and analysis of clinical trial data will also be conducted. The data base and computer science developments will be the responsibility of Frontier Science and Technology Research Foundation under a consortium agreement with the Harvard School of Public Health.

This grant is to provide statistical, computing and data management support for the Cancer and Acute Leukemia Group B (CALGB). These activities will involve collaboration in all appropriate activities associated with the planning, monitoring, data collection and analysis of data obtained from clinical trails conducted by the CALGB. Research and development of statistical methodology and computer software aimed at more effective planning, data management and analysis of clinical trials will also be conducted. The data base and computer science development will be the responsibility of Frontier Science and Technology Research Foundation under a consortium agreement with the Harvard School of Public Health.

Researchers at Harvard University and Aurora Flight Sciences are developing the Perseus unmanned aircraft as a dedicated platform for high-altitude atmospheric science research. Its initial mission is to carry a 50kg (110 lb) payload to an altitude of 25 km (82,000 ft) and return it for reuse. The combination of computationally based low Reynolds number aerodynamics, lightweight composite structures, and advanced microelectronics represented in Perseus promises to offer significant capability enhancements for a variety of atmospheric investigations, both research and operational. Some of the missions proposed to date include measuring the stratospheric chemistry, earth's radiation budget, determining sources and sinks of CO2 and CH4, studying stratosphere-troposphere exchange, hurricane research and forecasting, and tropical meteorology. Many of these missions require platforms with either high altitude capability or long duration.

Research in atmospheric chemistry has the ultimate goal of simulating by mathematical modeling any complex system of coupled chemical reactions in the atmosphere. The result can be the capability of predicting any changes in the composition of the atmosphere resulting from varying natural conditions or the introduction of man-made contaminants. The resolution of important practical and scientific problems requires the acquisition of the best possible values of the reaction speeds (kinetic constants) of the may elementary steps that make up the chemistry of the atmosphere. Among these problems are the stability of the stratospheric ozone layer, the appearance in urban air of secondary pollutants that were not present in the emissions of any contaminating source, and the course of evolution of planetary atmospheres, including the atmosphere of our own planet. This project attacks one of the most difficult, but necessary, aspects of atmospheric chemistry - the measurement of the reaction rates for chemical processes involving free radicals, most of which are unstable and extremely reactive fragments of the stable molecules of the atmosphere. Because they are so reactive, they occur in exceedingly low concentrations and are therefore measurable only by highly sophisticated techniques. It is their high reactivity, however, that makes them such active participants in the chemistry of the air and can allow them to determine the fate of more abundant species, such as hydrocarbons, sulfur dioxide, ozone, etc. The project will measure the reaction rates for several key chemical processes involving radical-radical and radical-molecule interactions in the sulfur, nitrogen, halogen, oxygen and hydrogen systems. These systems are important elements in contemporary approaches to the chemistries of clean and polluted air.

9302370 Anderson Water vapor is the dominant greenhouse gas and, as the original Central Equatorial Pacific Experiment (CEPEX) proposal pints out, water vapor is therefore the dominant regulator of the Earth's energy budget and thus the critical regulator of climate. An understanding of the processes that dictate the distribution of water vapor and the processes that link the distribution of water in all its phases to the frequency-dependent divergence of flux and radiance constitutes a central element in any considered strategy to understand secular trends of the Earth's climate. The PIs will augment the array of CEPEX observations with in situ observations of water vapor, ozone, pressure and temperature from the ER-2 aircraft. Water vapor measurements will be carried out using the Lyman- alpha photofragmentionion technique: Water vapor + hv hydroxyl(A) + hydrogen hydroxyl radical(X) + hv + hydrogen that fragments a water vapor molecule with 121.6 nm radiation from a plasma discharge lamp and observes 308 nm radiation from the electronically excited product hydroxyl radical. This experiment is done both in absorption and in fluorescence to provide a dynamic range of five orders of magnitude in water vapor concentration and an absolute calibration of the instrument during each flight. Ozone observations will be done using ultraviolet absorption in the Hartley continuum at 257nm. The instrument uses an on-board Hg resonance lamp; a MnO2 getter to establish the absorption cell count rate in the absence of ozone in the sample; a Roots blower to actively aspirate the measurement cell; and counting electronics to obtain fractional absorption levels of one part in 105. This research is important because it will provide water vapor and ozone observations needed to help interpret climate processes in a climate-sensitive part of the world. ***

9414843 Anderson Several key areas of atmospheric chemistry suffer from a lack of data on reaction rate coefficients and reaction mechanisms, especially in the conditions (pressure, temperature, and composition) of the Earth's atmosphere. These areas include (1) many of the reactions that limit the rate at which natural and anthropogenic free radicals in the stratosphere destroy ozone, (2) vital reactions that couple the chemical cycles of oxygen, nitrogen, and hydrogen throughout the troposphere and stratosphere, and (3) the mechanisms by which dimethylsulfide is oxidized in the remote atmosphere to form sulfate aerosols. In addition, many aspects of a comprehensive theory explaining the relative reactivity of molecules with free radicals are still not well developed. One objective of this research is to allow investigators to test simultaneous observations of many of the species central to atmospheric chemistry in order to determine whether laboratory chemistry agrees with atmospheric observations. Tests of this sort are currently hindered more by incomplete kinetic data than any other cause,particularly at the pressures (10 - 200 torr) and temperatures (185- 250 Kelvin) found in the upper troposphere and lower stratosphere. The investigators will employ a technique known as high pressure flow kinetics to probe numerous key reactions over the full range of tropospheric and lower stratospheric temperatures, pressures, and compositions. This technique, simultaneously avoids complicating wall reactions and extends the range of flow tube kinetics to atmospheric pressure. By avoiding wall reactions, experiments can be performed at temperatures far lower than previously obtainable. A second objective is enhanced knowledge of the oxidation pathways of dimethyl sulfide (DMS). DMS, a naturally occurring sulfur compound emitted from the ocean surface into the marine atmosphere, is the most important naturally occurring sulfur species in the atmosphere. It is believed to be the source of most of the aerosol particles in the marine atmosphere; these particles, in turn, serve as condensation nuclei for marine clouds. It has been postulated that the availability of these condensation nuclei affects the albedo of clouds, and thus that changes in DMS production caused by global climate change could in turn lead to further climate forcing, either ameliorating or worsening the initial effect. The sulfate aerosols also directly scatter a small portion of the incoming solar radiation away from the Earth's surface. The investigators will focus on three key points in a proposed DMS oxidation sequence in a effort to reconcile atmospheric observations with laboratory measurements. A key aspect of the work will be the observation of both reactant and product species in the reactions being studied. Fluorescence and absorption measurement of free radicals will be combined with high resolution Fourier transform infrared spectroscopy, which will allow simultaneous measurement of many species. The addition of a mass spectrometer will allow the detection of otherwise undetectable species at low concentrations, particularly in the DMS system.

With this award from the Chemistry Research Instrumentation and Facilities (CRIF) Program, the Department of Chemistry at Harvard University will acquire an FEI DualBeam 820 focused ion beam workstation. This instrument will facilitate research in a number of areas, including a) studies of step coverage in chemical vapor deposition of thin films; b) deposition of barrier materials; c) high dielectric constant materials; d) electrical properties of one-dimensional nanostructures; e) construction of nanotube probe microscopy tips; f) high resolution near-field fluorescence microscopy with nanofabricated metal tips for spectroscopic imaging of photosynthetic membranes; and g) near-field coherent anti-Stokes Raman spectroscopy studies of biological membranes.

A focused ion beam (FIB) in conjunction with a field-emission scanning electron microscope allows high-resolution in-situ imaging/monitoring of the nanofabrication process. The ability of FIB to fabricate and manipulate materials at the namometer scale is indispensable to the materials chemist since this length scale, which bridges both molecular and bulk systems, is expected to be the focus of much of chemical research in the future.

The research funded by this proposal will focus on unresolved questions about the chemistry of ozone catalysis (HOx, NOx, and ClOx) in the lower stratosphere. Laboratory experiments will address rate constants and mechanisms of reactions including OH+NO2, OH+HONO2, O+O3, Cl+RH, Cl+O3, and OH+HCl over the pressure and temperature ranges of the lower stratosphere, (50-200 torr). Experiments will employ a high pressure flow (HPF) technique, producing data that is distinct from and independent of pulsed laser photolysis studies. The HPF method enables rigorously wall-less experiments at arbitrary temperatures, while retaining the advantages of well-defined thermal radical distributions with no interference from other reagents. Radical measurements will be carried out with a combination of laser in-duced fluorescence (LIF), resonance fluorescence (RF), and infrared cavity ringdown laser absorption spectroscopy (IR-CRLAS). In situ FTIR absorption and in situ GC/MS analysis will insure both accurate quantification of molecular species and strict exclusion of contaminants, and laser doppler velocimetry will provide highly accurate velocity measurements. The experimental work will be combined with theoretical calculations to provide insight into the factors controlling these rates and mechanisms, which in turn will greatly increase confidence in the data. These calculations will focus simultaneously on the factors governing the potential energy surface for each reaction and on the dynamics on each surface.

This project is a laboratory study of a diverse set of atmospheric reactions potentially important to odd hydrogen (HOx) and organic analog (ROx) cycling in the troposphere and stratosphere. Initially, laboratory experiments will involve direct detection of short-lived intermediates and weakly bound complexes by isolating and identifying spectroscopic signatures. Reaction kinetics of these various reactive intermediates will then be studied using a variety of sensitive spectroscopic techniques and reactant flow systems designed to cover broad ranges of temperature and pressure representative of the ambient atmosphere (troposphere and stratosphere). Laboratory results will be combined with theoretical calculations involving quantum mechanical and statistical-dynamical computations. The broader impacts of this work include results that will be important in gaining a better understanding of the oxidative pathways controlling the oxidizing capacity of the Earth's atmosphere, and thereby improve greatly our understanding of some important reactions driving tropospheric and stratospheric chemistry. This project will also provide laboratory research training for three graduate students and one postdoctoral researcher.

The trace atmospheric free radical species, iodine monoxide (IO), is thought to be a key photochemical constituent in the marine boundary layer where it participates in ozone depletion reactions. It is also implicated in mercury removal processes occurring in the polar spring, and may take part in the formation of marine aerosols. Its potential reactivity with other radical families(NOx and HOx cycles), further underline its elusive reactivity in global photochemical processes in both the troposphere and stratosphere. However, its concentration and distribution over time and space are notably under-observed.
Instrumentation emplying laser-induced fluorescence spectroscopy, intended for either ground based or airborne use, will be constructed and implemented to have an estimated detection limit of 0.1 ppt per second or better. As well as presenting a challenging detection threshold, this fast response sensor is needed to resolve the expected highly inhomogeneous distribution of IO in marine boundary layers and other parts of the atmosphere.

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).

The primary objective of this project is to construct a new generation of field-deployable instrumentation capable of establishing simultaneously the isotopically differentiated (carbon-12 and carbon-13) fluxes of carbon dioxide and methane emitted from the carbon reservoirs of the high latitude permafrost regions of the Northern Hemisphere as these systems melt with the advance of increased temperatures. The determination of the fluxes of these carbon isotopes from Arctic carbon reservoirs is a critically important set of observations that is needed for the prediction of both the rate and irreversibility of the climate forcing resulting from the flow of heat into these systems. Observing these isotopic fluxes with the requisite precision and traceable accuracy in real time will be achieved with a new instrument that combines recent advances on multiple technological fronts including: Integrated Cavity Output Spectroscopy (ICOS) to achieve path lengths of 2 to 4 kilometers in a 50 centimeter cell, field-programmable gate-array based control electronics, advanced mid-infrared electro-optic technology, and high-level software fitting routines for data analysis.

This instrumentation development project will reflect the highly interdisciplinary nature of climate research at Harvard that directly links faculty, postdoctoral scientists, graduate and undergraduate students across the Departments of Earth and Planetary Sciences, Chemistry and Chemical Biology, and the School of Engineering and Applied Sciences, and will engage the Harvard University Center for the Environment. The new observations will involve highly collaborative activities with colleagues studying the fusion of in situ data with regional models, with colleagues studying the biogeochemistry of carbon dioxide and methane release from reservoirs at mid and high latitudes, with colleagues studying the paleorecord, with colleagues involved in developing computer modeling strategies for climate forecasting, and with the large community of undergraduates and graduate students at Harvard and at other universities across the country. Student-level engagement from concept to completion is crucial, not only to the successful construction and deployment of the proposed carbon isotope instrument, but to the broader scientific future of the United States, which will come to rely even more on scientists whose training and philosophy is centered on the physical sciences in the service of key societal objectives. Because of the scale of the carbon flux problem, the design of the instrument will be made freely available to the broader climate research community.

This proposal directly addresses the release of carbon dioxide and methane from terrestrial melt zones and ocean systems that result from the loss of the Arctic Ocean ice cover. Airborne measurements of the fluxes of isotopologues of methane and carbon dioxide will be conducted using a new spectrometer system developed at Harvard under an NSF MRI initiative. This instrument has sufficient precision and accuracy to distinguish between thermogenic and biogenic sources of carbon in the Arctic, as well as measuring N2O and water vapor, as well as other tracers. NOAA?s Atmospheric Turbulence and Division Division (ATDD) bring their expertise in field deployments of airborne flux systems as well as a Best Air Turbulence (BAT) probe to the field mission. The broader impacts of the proposed activity emerge from the unique measurements and monitoring strategy of this project to develop a foundation for a national carbon monitoring network, which will be a key component of any program or international agreement to limit carbon emissions. The project will fill a technological void and deliver a system that is versatile by design, allowing for myriad future applications that are centered on specific carbon-related issues, such as sequestration and forest chemistry, as well as assessing the overall country-by-country inventory of carbon.

This research includes the deployment of instrumentation to study ozone loss over the central United States in summer. The instrumentation will be integrated onto a new generation of solar powered stratospheric aircraft. Ozone loss over the over the central US in summer could result in an associated increase in exposure to UV radiation at the surface.

Recent observations have associated certain atmospheric flow patterns and convective storms over the central U.S. in summer with conditions that may lead to the amplification in the catalytic loss rates of ozone for the dominant halogen, hydrogen, and nitrogen catalytic cycles. These observations define for the first time (a) the frequency and depth of convective penetration of water into the stratosphere over the United States in summer employing the NEXRAD weather radar network, (b) the altitude dependent distribution of inorganic chlorine established in the same coordinate system as the radar observations, (c) the high accuracy, high spatial resolution temperature structure of the stratosphere over the US in summer that resolves spatial and structural variability of temperature, including the impact of gravity waves on the temperature structure, and (d) the resulting amplification in the catalytic loss rates of ozone for the dominant halogen, hydrogen, and nitrogen catalytic cycles. These new observations imply significantly increased risk of ozone loss over the Great Plains in summer.