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All sourcesNASA NTRSDOE OSTI
DOE OSTI2011

Distributed Wind Policy Comparison Tool

Power through Policy: 'Best Practices' for Cost-Effective Distributed Wind is a U.S. Department of Energy (DOE)-funded project to identify distributed wind technology policy best practices and to help policymakers, utilities, advocates, and consumers examine their effectiveness using a pro forma model. Incorporating a customized feed from the Database of State Incentives for Renewables and Efficiency (DSIRE), the Web-based Distributed Wind Policy Comparison Tool (Policy Tool) is designed to assist state, local, and utility officials in understanding the financial impacts of different policy options to help reduce the cost of distributed wind technologies. The Policy Tool can be used to evaluate the ways that a variety of federal and state policies and incentives impact the economics of distributed wind (and subsequently its expected market growth). It also allows policymakers to determine the impact of policy options, addressing market challenges identified in the U.S. DOE’s '20% Wind Energy by 2030' report and helping to meet COE targets.

distributed↗
DOE OSTI2013

Algae Biofuels Co-Location Assessment Tool

ABCLAT was built to help any model user with spatially explicit Nitrogen, Phosphorous, and Carbon Dioxide nutrient flux information, and solar resource information evaluate algal cultivation potential. Initial applications of this modeling framework include Algae Biofuels Co-Location Assessment Tool Canada and Australia. The Canadian application was copyrighted November 29th 2011 as the Algae Biofuels Co-Location Assessment Tool for Canada. This copyright assertion is for the general framework from which any country or region with the requisite data could create a regionally specific application. The ABCLAT model framework developed by SNL looks at the growth potential in a given region as a function of available nutrients from wastewater and other sources, carbon dioxide from power plants, available solar potential, and if available, land cover and use information. The model framework evaluates the biomass potential, fixed carbon dioxide, potential algal biocrude and required land area for nutrient sources. ABCLAT is built with an object-oriented software program that can provide an easy to use interface for exploring questions related to aigal biomass production.

Source record↗
DOE OSTI2013

Improved Management of the Technical Interfaces Between the Hanford Tank Farm Operator and the Hanford Waste Treatment Plant - 13383

The Department of Energy (DOE) is constructing the Waste Treatment and Immobilization Plant (WTP) at the Hanford site in Washington to treat and immobilize approximately 114 million gallons of high level radioactive waste (after all retrievals are accomplished). In order for the WTP to be designed and operated successfully, close coordination between the WTP engineering, procurement, and construction contractor, Bechtel National, Inc. and the tank farms operating contractor (TOC), Washington River Protection Solutions, LLC, is necessary. To develop optimal solutions for DOE and for the treatment of the waste, it is important to deal with the fact that two different prime contractors, with somewhat differing contracts, are tasked with retrieving and delivering the waste and for treating and immobilizing that waste. The WTP and the TOC have over the years cooperated to manage the technical interface. To manage what is becoming a much more complicated interface as the WTP design progresses and new technical issues have been identified, an organizational change was made by WTP and TOC in November of 2011. This organizational change created a co-located integrated project team (IPT) to deal with mutual and interface issues. The Technical Organization within the One System IPT includes employees from both TOC and WTP. This team has worked on a variety of technical issues of mutual interest and concern. Technical issues currently being addressed include: - The waste acceptance criteria; - Waste feed delivery and the associated data quality objectives (DQO); - Evaluation of the effects of performing a riser cut on a single shell tank on WTP operations; - The disposition of secondary waste from both TOC and WTP; - The close coordination of the TOC double shell tank mixing and sampling program and the Large Scale Integrated Test (LSIT) program for pulse jet mixers at WTP along with the associated responses to the Defense Nuclear Facilities Safety Board (DNFSB) Recommendation 2010-2; - Development of a set of alternatives to the current baseline that involve aspects of direct feed, feed conditioning, and design changes. The One System Technical Organization has served WTP, TOC, and DOE well in managing and resolving issues at the interface. This paper describes the organizational structure used to improve the interface and several examples of technical interface issues that have been successfully addressed by the new organization. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2014

Measurements of Space Radiation On, and On the Way To, Mars - Paper 123

The Mars Science Laboratory (MSL) spacecraft, with the Curiosity rover inside, was launched to Mars on November 25, 2011, and landed successfully on August 6, 2012. Curiosity's science payload includes ten science instruments, one of which is the Radiation Assessment Detector, RAD. The radiation environment in deep space is harsh, and is a limiting factor in planning future human missions. RAD's measurements of the radiation environments on Mars, and on a spacecraft during transit to Mars, are important precursors to a crewed mission. RAD is a compact instrument with a mass of just 1.56 kg. Despite its small size, RAD is capable of measuring the charged and neutral particles that make up the complex environments created by Galactic Cosmic Rays (GCRs) and Solar Energetic Particles (SEPs) as they traverse shielding materials. The space radiation environment consists of a continuous flux of GCRs, the intensity of which is modulated by solar activity. At or near times of solar maximum, the interplanetary magnetic field is relatively strong, and lower-energy GCRs are screened. At solar minimum, the field weakens with a corresponding increase in GCR fluxes. SEP events are sporadic, and are more likely to occur near solar maximum. Both GCRs and SEPs present potential health risks to astronauts, but the risks are of different types. The dose rate from GCRs is modest and cannot cause acute health effects. However serious late effects may arise; of particular concern are the largely unknown health effects of exposure to high-energy GCR heavy ions. There is no terrestrial analog for this exposure and this leads to large uncertainties in health risk estimates. In contrast, SEP events can be extremely intense and could potentially cause acute health effects, but they are also dominated by protons with energies below 100 MeV, which means that shielding is a practical and effective option. (authors)

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2011

Three-Dimensional Numerical Evaluation of Thermal Performance of Uninsulated Wall Assemblies

This study describes a detailed 3D computational fluid dynamics model that evaluates the thermal performance of uninsulated wall assemblies. It accounts for conduction through framing, convection, and radiation and allows for material property variations with temperature. This research was presented at the ASME 2011 International Mechanical Engineering Congress and Exhibition; Denver, Colorado; November 11-17, 2011

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2015

Site Investigation Results, 2009-2011, Inman, Kansas (Final Report)

The Commodity Credit Corporation of the U.S. Department of Agriculture (CCC/USDA) operated a grain storage facility at the southern edge of the city of Inman, Kansas, from 1954 to 1965. During this time, commercial grain fumigants containing carbon tetrachloride were in common use by the grain storage industry to preserve grain in their facilities. In 1997, trace to low levels of carbon tetrachloride (below the maximum contamination level [MCL] of 5.0 µg/L) were detected in three private wells near the former grain storage facility at Inman, as part of a statewide USDA private well sampling program that was implemented by the Kansas Department of Health and Environment (KDHE) near former CCC/USDA facilities. No public water supply wells were identified in 1998 by the KDHE within 1 mi of the town. Carbon tetrachloride is the contaminant of primary concern at sites associated with grain storage operations. To determine whether the former CCC/USDA facility at Inman is a potential contaminant source and its possible relationship to the contamination in groundwater, the CCC/USDA agreed to conduct investigations at Inman. The investigations were performed by the Environmental Science Division of Argonne National Laboratory in accordance with the Intergovernmental Agreement between the KDHE and the Farm Service Agency of the USDA. Argonne, on behalf of the CCC/USDA, developed a Work Plan (Argonne 2007) and subsequently a Summary of Investigation Results and Proposed Work Plan (Appendix A) for a phased site investigation. The proposed work was approved by the KDHE (2007, 2011). The investigations were conducted from November 2009 to September 2011, as proposed in the two work plans. This report presents the findings of the 2009-2011 investigations at Inman.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2015

FInal Report: Site Investigation Results, 2009-2011, at Inman, Kansas

The Commodity Credit Corporation of the U.S. Department of Agriculture (CCC/USDA) operated a grain storage facility at the southern edge of the city of Inman, Kansas, from 1954 to 1965. During this time, commercial grain fumigants containing carbon tetrachloride were in common use by the grain storage industry to preserve grain in their facilities. In 1997, trace to low levels of carbon tetrachloride (below the maximum contamination level [MCL] of 5.0 μg/L) were detected in three private wells near the former grain storage facility at Inman, as part of a statewide USDA private well sampling program that was implemented by the Kansas Department of Health and Environment (KDHE) near former CCC/USDA facilities. No public water supply wells were identified in 1998 by the KDHE within 1 mi of the town. Carbon tetrachloride is the contaminant of primary concern at sites associated with grain storage operations. To determine whether the former CCC/USDA facility at Inman is a potential contaminant source and its possible relationship to the contamination in groundwater, the CCC/USDA agreed to conduct investigations at Inman. The investigations were performed by the Environmental Science Division of Argonne National Laboratory in accordance with the Intergovernmental Agreement between the KDHE and the Farm Service Agency of the USDA. Argonne, on behalf of the CCC/USDA, developed a Work Plan (Argonne 2007) and subsequently a Summary of Investigation Results and Proposed Work Plan (Appendix A) for a phased site investigation. The proposed work was approved by the KDHE (2007, 2011). The investigations were conducted from November 2009 to September 2011, as proposed in the two work plans. This report presents the findings of the 2009-2011 investigations at Inman.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS2011

Summary Report for National Aeronautics Space Administration (NASA) and Centro Para Prevencao da Poluicao (C3P) 2011 International Workshop on Environment and Alternative Energy

The C3P &. NASA International Workshop on Environment and Alternative Energy was held on November 15-18, 2011 at the European Space Agency (ESA)'s Research and Technology Centre (ESTEC) in Noordwijk, The Netherlands. The theme of the workshop was "Global Collaboration in Environmental and Alternative Energy Strategies". The workshop was held at ESTEC's conference center. More than 110 individuals from eleven countries attended the workshop. For the first time since the inception of NASA-C3P workshops, a full day was dedicated to a student session. Fifteen students from around the globe gave oral presentations along with poster displays relating to the latest technologies in environmental and alternative energy strategies. Judges from NASA, C3P and ESA awarded plaques to the top three students. In addition to the students, thirty eight U.S. and international subject matter experts presented on the following general environmental-related topics: (1) Hazardous materials management and substitution in support of space operations (2) Emerging renewable and alternative energy technologies (3) Sustainable development and redevelopment (4) Remediation technologies and strategies The workshop also included a panel discussion on the topic of the challenges of operating installations across borders. Throughout the workshop, attendees heard about the scope of environmental and energy challenges that industry and governments face. They heard about technologies for increasing energy efficiency and increasing use of renewable energy. They learned about ways companies and government agencies are using materials, processes, goods and services in a manner more respectful with the environment and in compliance with health and safety rules. The concept of partnerships and their inherent benefits was evidenced throughout the workshop. Partnering is a key aspect of sustainability because sustainable development is complicated. Through formal presentations and side discussions, attendees commented on the need for continued exploration of joint projects of mutual interest.

Greene, Brian↗
DOE OSTI2012

Beyond the born approximation: Measuring the two-photon exchange effect at CLAS

Recent results from experiments at Jefferson Laboratory, Newport News VA, which measured the ratio of the electric to magnetic form factors of the proton, G{sub E}/G{sub M}, have forced us to reexamine the single photon exchange approximation in lepton-proton elastic scattering. Discrepancies between the ratio obtained via the time-tested Rosenbluth separation method and newer polarization transfer measurements, which differ by as much as a factor of three, may be resolved by considering the effect of two photon exchange (TPE) processes. The CLAS TPE experiment at Jefferson Laboratory, will determine the effect of two-photon exchange in elastic lepton-proton scattering by precisely measuring the ratio of positron-proton to electron-proton elastic cross sections over a large kinematic range (0.1 < {xi} < 0.96, 0.2 {ge} Q{sup 2} {le} 2.0 GeV{sup 2}). We accomplish this by directing the 5.5 GeV primary electron beam, provided by the Continuous Electron Beam Accelerator Facility (CEBAF), onto a set of radiators and converters to produce simultaneous and identical beams of electron and positrons which collide with our proton target. Acceptance and efficiency concerns are minimized by only considering the ratios of the elastic cross sections and by switching polarity of magnets in the beamline and the spectrometer. Guided by the results of a short 2006 test run and extensive GEANT based modeling, new shielding and beamline components were designed to maximize luminosity. We took data from November 2010 - February 2011. The unique experimental design and challenges of the TPE experiment and the current analysis status will be presented.

43 PARTICLE ACCELERATORS↗
DOE OSTI2012

Review of APR+ Level 2 PSA. Revision 2

Brookhaven National Laboratory (BNL) assisted the Korea Institute of Nuclear Safety (KINS) in reviewing the Level 2 Probabilistic Safety Assessment (PSA) of the APR+ Advanced Pressurized Water Reactor (PWR) prepared by the Korea Hydro & Nuclear Power Co., Ltd (KHNP) and KEPCO Engineering & Construction Co., Inc. (KEPCO-E&C). The work described in this report involves a review of the APR+ Level 2 PSA submittal [Ref. 1]. The PSA and, therefore, the review is limited to consideration of accidents initiated by internal events. As part of the review process, the review team also developed three sets of Requests for Additional Information (RAIs). These RAIs were provided to KHNP and KEPCO-E&C for their evaluation and response. This final detailed report documents the review findings for each technical element of the PSA and includes consideration of all of the RAIs made by the reviewers as well as the associated responses. This final report was preceded by an interim report [Ref. 2] that focused on identifying important issues regarding the PSA. In addition, a final meeting on the project was held at BNL on November 21-22, 2011, where BNL and KINS reviewers discussed their preliminary review findings with KHNP and KEPCO-E&C staffs. Additional information obtained during this final meeting was also used to inform the review findings of this final report. The review focused not only on the robustness of the APR+ design to withstand severe accidents, but also on the capability and acceptability of the Level 2 PSA in terms of level of detail and completeness. The Korean nuclear regulatory authorities will decide whether the PSA is acceptable and the BNL review team is providing its comments for KINS consideration. Section 2.0 provides the basis for the BNL review. Section 3.0 presents the review of each technical element of the PSA. Conclusions and a summary are presented in Section 4.0. Section 5.0 contains the references.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2012

Wind Turbine Tribology Seminar - A Recap

Tribology is the science and engineering of interacting surfaces in relative motion. It includes the study and application of the principles of friction, lubrication, and wear. It is an important phenomenon that not only impacts the design and operation of wind turbine gearboxes, but also their subsequent maintenance requirements and overall reliability. With the major growth and increasing dependency on renewable energy, mechanical reliability is an extremely important issue. The Wind Turbine Tribology Seminar was convened to explore the state-of-the-art in wind turbine tribology and lubricant technologies, raise industry awareness of a very complex topic, present the science behind each technology, and identify possible R&D areas. To understand the background of work that had already been accomplished, and to consolidate some level of collective understanding of tribology by acknowledged experts, the National Renewable Energy Laboratory (NREL), Argonne National Laboratory (ANL), and the U.S. Department of Energy (DOE) hosted a wind turbine tribology seminar. It was held at the Renaissance Boulder Flatiron Hotel in Broomfield, Colorado on November 15-17, 2011. This report is a summary of the content and conclusions.

17 WIND ENERGY↗
DOE OSTI2011

International Symposium on Clusters and Nanostructures (Energy, Environment, and Health)

The international Symposium on Clusters and Nanostructures was held in Richmond, Virginia during November 7-10, 2011. The symposium focused on the roles clusters and nanostructures play in solving outstanding problems in clean and sustainable energy, environment, and health; three of the most important issues facing science and society. Many of the materials issues in renewable energies, environmental impacts of energy technologies as well as beneficial and toxicity issues of nanoparticles in health are intertwined. Realizing that both fundamental and applied materials issues require a multidisciplinary approach the symposium provided a forum by bringing researchers from physics, chemistry, materials science, and engineering fields to share their ideas and results, identify outstanding problems, and develop new collaborations. Clean and sustainable energy sessions addressed challenges in production, storage, conversion, and efficiency of renewable energies such as solar, wind, bio, thermo-electric, and hydrogen. Environmental issues dealt with air- and water-pollution and conservation, environmental remediation and hydrocarbon processing. Topics in health included therapeutic and diagnostic methods as well as health hazards attributed to nanoparticles. Cross-cutting topics such as reactions, catalysis, electronic, optical, and magnetic properties were also covered.

Jena, Puru↗
NASA NTRS2015

A High-Resolution Merged Wind Dataset for DYNAMO: Progress and Future Plans

In order to support research on optimal data assimilation methods for the Cyclone Global Navigation Satellite System (CYGNSS), launching in 2016, work has been ongoing to produce a high‐resolution merged wind dataset for the Dynamics of the Madden Julian Oscillation (DYNAMO) field campaign, which took place during late 2011/early 2012. The winds are produced by assimilating DYNAMO observations into the Weather Research and Forecasting (WRF) three‐dimensional variational (3DVAR) system. Data sources from the DYNAMO campaign include the upper‐air sounding network, radial velocities from the radar network, vector winds from the Advanced Scatterometer (ASCAT) and Oceansat‐2 Scatterometer (OSCAT) satellite instruments, the NOAA High Resolution Doppler Lidar (HRDL), and several others. In order the prep them for 3DVAR, significant additional quality control work is being done for the currently available TOGA and SMART‐R radar datasets, including automatically dealiasing radial velocities and correcting for intermittent TOGA antenna azimuth angle errors. The assimilated winds are being made available as model output fields from WRF on two separate grids with different horizontal resolutions ‐ a 3‐km grid focusing on the main DYNAMO quadrilateral (i.e., Gan Island, the R/V Revelle, the R/V Mirai, and Diego Garcia), and a 1‐km grid focusing on the Revelle. The wind dataset is focused on three separate approximately 2‐week periods during the Madden Julian Oscillation (MJO) onsets that occurred in October, November, and December 2011. Work is ongoing to convert the 10‐m surface winds from these model fields to simulated CYGNSS observations using the CYGNSS End‐To‐End Simulator (E2ES), and these simulated satellite observations are being compared to radar observations of DYNAMO precipitation systems to document the anticipated ability of CYGNSS to provide information on the relationships between surface winds and oceanic precipitation at the mesoscale level. This research will improve our understanding of the future utility of CYGNSS for documenting key MJO processes.

Lang, Timothy J.↗
NASA NTRS2023

SNPP and N20 VIIRS Day/Night Band (DNB) Calibration and Performance

The first two Visible Infrared Imaging Radiometer Suite (VIIRS) instruments, on-board the Suomi National Polar-orbiting Partnership (SNPP) and the NOAA-20 (N20) satellites, have been operating for over 11 and 5 years since their launches on28 October 2011 and 18 November 2017 respectively. The day-night band (DNB) onboard VIIRS is a panchromatic visible/near-infrared (Vis/NIR) channel designed to detect radiance from the brightest daytime scenes down to very dim nighttime scenes illuminated by a quarter moon. In this paper, we present the SNPP and N20 VIIRS DNB calibration results performed by the NASA VIIRS Characterization Support Team (VCST) to generate the calibration coefficient look up tables (LUTs) for the latest NASA Level 1B Collection 2 products. The differing DNB straylight contamination between VIIRS instruments is discussed along with the correction methodology and performance.

Junqiang Sun↗
DOE OSTI2011

Measurements of the Two-Photon Exchange Effect in Lepton-Proton Elastic Scattering at CLAS

Recent results from experiments at Jefferson Laboratory, Newport News VA, which measured the ratio of the electric to magnetic form factors of the proton, GE/GM, have forced us to reexamine the single photon exchange approximation in lepton-proton elastic scattering. Discrepancies between the ratio obtained via the time-tested Rosenbluth separation method and newer polarization transfer measurements, which differ by as much as a factor of three, may be resolved by considering the effect of two photon exchange (TPE) processes. The CLAS TPE experiment at Jefferson Laboratory, will determine the effect of two-photon exchange in elastic lepton-proton scattering by precisely measuring the ratio of positron-proton to electron- proton elastic cross sections over a large kinematic range (0.1 < epsilon < 0.96, 0.2 <= Q2 <= 2.0GeV 2). We accomplish this by directing the 5.5 GeV primary electron beam, provided by the Continuous Electron Beam Accelerator Facility (CEBAF), onto a set of radiators and converters to produce simultaneous and identical beams of electron and positrons which collide with our proton target. Acceptance and efficiency concerns are minimized by only considering the ratios of the elastic cross sections and by switching polarity of magnets in the beamline and the spectrometer. Guided by the results of a short 2006 test run and extensive GEANT based modeling, new shielding and beamline components were designed to maximize luminosity. We took data from November 2010 ? February 2011. The unique experimental design and challenges of the TPE experiment and the current analysis status will be presented.

Bennett, Robert↗
DOE OSTI2013

Postpartum Hemorrhage Treated with Gelfoam Slurry Embolization Using the Superselective Technique: Immediate Results and 1-Month MRI Follow-up

To evaluate the efficacy and safety of superselective embolization of the uterine arteries in a postpartum hemorrhage. Between November 2004 and January 2011, a total of 44 consecutive women (median {+-} standard deviation age 34 {+-} 3 years, range 23-41 years) were referred to our institution for postpartum intractable hemorrhage management. All patients were embolized with a microcatheter that was placed deep into the uterine arteries upstream of the cervical arteries. The embolic agent was a mixture of contrast medium and 5 Multiplication-Sign 5 Multiplication-Sign 5 cm pieces of gelfoam (Gelita-Spon) modified into a gelatin emulsion as follows: rapid mixing through a three-way stopcock with two 2.5-ml syringes. A 1-ml syringe was used for injection. One month after embolization, all patients underwent magnetic resonance imaging and clinical examination. Technical and clinical success was obtained in all cases. Thirty-five patients experienced bleeding related to poor retraction of the uterus, 7 patients because of a tear of the cervix and 2 because of a vaginal hematoma. Pre- and postembolization red blood cell transfusions were (mean {+-} standard deviation [SD]) 6 {+-} 1.2 (range 3-8) U and 2 {+-} 0.7 (range 2-4) U, respectively. One-month magnetic resonance imaging follow-up revealed no sign of ischemic myometrium or necrosis, and no instances of uterine rupture and no pelvic vein thrombosis. Incidental findings included two small intramyometrial hematic collections. All uterine arteries were patent via magnetic resonance angiography. Seventeen patients had concomitant fibroids, all of which appeared hypovascular. This technique permits good, safe clinical results with no marked damage to the uterine arteries or the uterus itself.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2015

Prospective Evaluation of the Optimal Duration of Bed Rest After Vascular Interventions Using a 3-French Introducer Sheath

PurposeTo assess optimal bed-rest duration after vascular intervention by way of the common femoral artery using 3F introducer sheaths.Materials and MethodsEligibility criteria for this single-center, prospective study included clinically necessary angiography, no coagulopathy or anticoagulant therapy, no hypersensitivity to contrast medium, age >20 years, and written, informed consent. Enrolled patients were assigned to one of three groups (105/group) with the duration of bed rest deceased sequentially. A sheath was inserted by way of the common femoral artery using the Seldinger technique. The first group (level 1) received 3 h of bed rest after the vascular intervention. If no bleeding or hematomas developed, the next group (level 2) received 2.5 h of bed rest. If still no bleeding or hematomas developed, the final group (level 3) received 2 h of bed rest. If any patient had bleeding or hematomas after bed rest, the study was terminated, and the bed rest of the preceding level was considered the optimal duration.ResultsA total of 105 patients were enrolled at level 1 between November 2010 and September 2011. Eight patients were excluded from analysis because cessation of bed rest was delayed. None of the remaining subjects experienced postoperative bleeding; therefore, patient enrollment at level 2 began in September 2011. However, puncture site bleeding occurred in the 52nd patient immediately after cessation of bed rest, necessitating study termination.ConclusionTo prevent bleeding, at least 3 h of postoperative bed rest is recommended for patients undergoing angiography using 3F sheaths.

62 RADIOLOGY AND NUCLEAR MEDICINE↗
DOE OSTI2018

Revealing the causes and temporal distribution of tree mortality in Central Amazonia

Tree mortality is a critical process in forest ecosystems, as it influences floristic composition, structure, dynamics, carbon storage, and forest nutrient cycling. However, the mechanisms behind tree death in tropical regions are still poorly characterized. This lack of information is mainly because tree mortality data come from long-interval inventories and studies that measured tree death seasonally are scarce. Here in this study, we offer novel insights into the power of fine temporal scale observations and we use a natural history approach to understand the processes and mechanism of tree mortality. We monitored tree mortality every month during one year, in 10 ha of terra-firme forest. To determine the pathways of mortality, we considered the state of the tree at the start of the investigation and the pre and post-mortem characteristics. From November 2010 to October 2011, 67 out of 5808 trees died. Despite the 2010 drought, mortality was highly correlated with monthly rainfall (r = 0.85). In total, six pathways of mortality were assessed. Storms were the main cause of mortality, killing 45% of all dead trees, followed by Biotic/abiotic factors accounting for 30% of tree mortality. The high mortality registered in the rainy season was mostly (78%) due to healthy trees dying uprooted or snapped. Lastly, we would benefit from studies that assess mortality on a monthly basis and in combination with quantitative long-term data, we can substantially improve our understanding of the mechanisms behind tree death in the tropics.

2010 drought↗