Search NASA⌕ Search

SEARCH · Search NASA

Results for “2011”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2014

Electron reconstruction and identification efficiency measurements with the ATLAS detector using the 2011 LHC proton–proton collision data

Many of the interesting physics processes to be measured at the LHC have a signature involving one or more isolated electrons. The electron reconstruction and identification efficiencies of the ATLAS detector at the LHC have been evaluated using proton–proton collision data collected in 2011 at √s = 7 TeV and corresponding to an integrated luminosity of 4.7 fb -1 . Tag-and-probe methods using events with leptonic decays of W and Z bosons and J/ψ mesons are employed to benchmark these performance parameters. The combination of all measurements results in identification efficiencies determined with an accuracy at the few per mil level for electron transverse energy greater than 30 GeV.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2016

The performance of the jet trigger for the ATLAS detector during 2011 data taking

The performance of the jet trigger for the ATLAS detector at the LHC during the 2011 data taking period is described. During 2011 the LHC provided proton–proton collisions with a centre-of-mass energy of 7 TeV and heavy ion collisions with a 2.76 TeV per nucleon–nucleon collision energy. The ATLAS trigger is a three level system designed to reduce the rate of events from the 40 MHz nominal maximum bunch crossing rate to the approximate 400 Hz which can be written to offline storage. The ATLAS jet trigger is the primary means for the online selection of events containing jets. Events are accepted by the trigger if they contain one or more jets above some transverse energy threshold. During 2011 data taking the jet trigger was fully efficient for jets with transverse energy above 25 GeV for triggers seeded randomly at Level 1. For triggers which require a jet to be identified at each of the three trigger levels, full efficiency is reached for offline jets with transverse energy above 60 GeV. Jets reconstructed in the final trigger level and corresponding to offline jets with transverse energy greater than 60 GeV, are reconstructed with a resolution in transverse energy with respect to offline jets, of better than 4 % in the central region and better than 2.5 % in the forward direction.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2015

Application of an Online-Coupled Regional Climate Model, WRF-CAM5, over East Asia for Examination of Ice Nucleation Schemes: Part I. Comprehensive Model Evaluation and Trend Analysis for 2006 and 2011

Online-coupled climate and chemistry models are necessary to realistically represent the interactions between climate variables and chemical species and accurately simulate aerosol direct and indirect effects on cloud, precipitation, and radiation. In this Part I of a two-part paper, simulations from the Weather Research and Forecasting model coupled with the physics package of Community Atmosphere Model (WRF-CAM5) are conducted with the default heterogeneous ice nucleation parameterization over East Asia for two full years: 2006 and 2011. A comprehensive model evaluation is performed using satellite and surface observations. The model shows an overall acceptable performance for major meteorological variables at the surface and in the boundary layer, as well as column variables (e.g., precipitation, cloud fraction, precipitating water vapor, downward longwave and shortwave radiation). Moderate to large biases exist for cloud condensation nuclei over oceanic areas, cloud variables (e.g., cloud droplet number concentration, cloud liquid and ice water paths, cloud optical depth, longwave and shortwave cloud forcing). These biases indicate a need to improve the model treatments for cloud processes, especially cloud droplets and ice nucleation, as well as to reduce uncertainty in the satellite retrievals. The model simulates well the column abundances of chemical species except for column SO 2 but relatively poor for surface concentrations of several species such as CO, NO 2 , SO 2 , PM2.5, and PM10. Several reasons could contribute to the underestimation of major chemical species in East Asia including underestimations of anthropogenic emissions and natural dust emissions, uncertainties in the spatial and vertical distributions of the anthropogenic emissions, as well as biases in meteorological, radiative, and cloud predictions. Despite moderate to large biases in the chemical predictions, the model performance is generally consistent with or even better than that reported for East Asia with only a few exceptions. The model generally reproduces the observed seasonal variations and the difference between 2006 and 2011 for most variables or chemical species. Overall, these results demonstrate promising skills of WRF-CAM5 for long-term simulations at a regional scale and suggest several areas of potential improvements.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2013

2011 Community Earth System Model (CESM) Tutorial, August 1-5, 2011

In fiscal year 2011, the Community Earth System Model (CESM) tutorial was taught at NCAR from 1-5 August 2011. This project hosted 79 full participants (1 accepted participant from China couldn't get a visa) selected from 180 applications. The tutorial was advertised through emails to CESM mailing lists. NCAR staff and long-term visitors (who were not eligible to attend) were also invited to 'audit' the climate and practical lectures and to work on the practical sessions on their own. 15 NCAR staff and long-term visitors took advantage of this opportunity. The majority of the students were graduate students, but several post-docs, faculty, and other research scientists also attended. Additionally, many people are using the on-line lessons and practical sessions. As of August 18, 2011, 407 people had registered to access and use the tutorial from 33 countries all over the world, but a majority from US universities. In fiscal year 2011, the Climate and Global Dynamics Division Information Systems Group (CGD/ISG) built and operated a temporary computer laboratory in a meeting room. This project was made possible through funding from the National Science Foundation Directorate of Geosciences, and the Department of Energy Office of Science.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2014

12th IAEA Technical Meeting on Energetic Particles in Magnetic Confinement Systems (7–11 September 2011) and 5th IAEA Technical Meeting on Theory of Plasma Instabilities (5–7 September 2011)

The 12th IAEA Technical Meeting on Energetic Particles in Magnetic Confinement Systems took place in Austin, Texas (7–11 September 2011). This meeting was organized jointly with the 5th IAEA Technical Meeting on Theory of Plasma Instabilities (5–7 September 2011). The two meetings shared one day (7 September 2011) with presentations relevant to both groups. Some of the work reported at these meetings was then published in a special issue of Nuclear Fusion [Nucl. Fusion 52 (2012)]. Summaries of the Energetic Particle Conference presentations were given by Kazuo Toi and Boris Breizman. They respectively discussed the experimental and theoretical progress presented at the meeting. Highlights of this meeting include the tremendous progress that has been achieved in the development of diagnostics that enables the ‘viewing’ of internal fluctuations and allows comparison with theoretical predictions, as demonstrated, for example, in the talks of P. Lauber and M. Osakabe. The need and development of hardened diagnostics in the severe radiation environment, such as those that will exist in ITER, was discussed in the talks of V. Kiptily and V.A. Kazakhov. In theoretical studies, much of the effort is focused on nonlinear phenomena. For example, detailed comparison of theory and experiment on D-III-D on the n = 0 geodesic mode was reported in separate papers by R. Nazikian and G. Fu. A large number of theoretical papers were presented on wave chirping including a paper by B.N. Breizman, which notes that wave chirping from a single frequency may emanate continuously once marginal stability conditions have been established. Another area of wide interest was the detailed study of alpha orbits in a burning plasma, where losses can come from symmetry breaking due to finite coil number or magnetic field imperfections introduced by diagnostic or test modules. An important area of development, covered by M.A. Hole and D.A. Spong, is concerned with the self-consistent treatment of the induced fields that accounts for toroidally asymmetric MHD response. In addition, a significant number of studies focused on understanding nonlinear behavior by means of computer simulation of energetic particle driven instability. An under-represented area of investigation was the study of electron runaway formation during major tokamak disruptions. It was noted in an overview by S. Putvinski that electron energies in the 10–20 MeV range is to be expected during projected major disruptions in ITER and that reliable methods for mitigation of the runaway process needs to be developed. Significant recent work in the field of the disruption induced electron runaway, which was reported by J. Riemann, had been submitted to Physics of Plasmas. Overall it is clear that reliable mitigation of electron runaway is an extremely important topic that is in need of better understanding and solutions.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2013

CHANDRA, KECK, AND VLA OBSERVATIONS OF THE CRAB NEBULA DURING THE 2011-APRIL GAMMA-RAY FLARE

We present results from our analysis of Chandra X-Ray Observatory, W. M. Keck Observatory, and Karl G. Jansky Very Large Array (VLA) images of the Crab Nebula that were contemporaneous with the {gamma}-ray flare of 2011 April. Despite hints in the X-ray data, we find no evidence for statistically significant variations that pinpoint the specific location of the flares within the Nebula. The Keck observations extend this conclusion to the 'inner knot', i.e., the feature within an arcsecond of the pulsar. The VLA observations support this conclusion. We also discuss theoretical implications of the {gamma}-ray flares and suggest that the most dramatic {gamma}-ray flares are due to radiation-reaction-limited synchrotron emission associated with sudden, dissipative changes in the current system sustained by the central pulsar.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2014

Measurement of the muon reconstruction performance of the ATLAS detector using 2011 and 2012 LHC proton–proton collision data

This study presents the performance of the ATLAS muon reconstruction during the LHC run with pp collisions at √s = 7–8 TeV in 2011–2012, focusing mainly on data collected in 2012. Measurements of the reconstruction efficiency and of the momentum scale and resolution, based on large reference samples of J/ψ → μμ, Z → μμ and Υ → μμ decays, are presented and compared to Monte Carlo simulations. Corrections to the simulation, to be used in physics analysis, are provided. Over most of the covered phase space (muon |η| < 2.7 and 5 ≲ p T ≲ 100 GeV) the efficiency is above 99% and is measured with per-mille precision. The momentum resolution ranges from 1.7% at central rapidity and for transverse momentum p T ≃ 10 GeV, to 4% at large rapidity and p T ≃ 100 GeV. The momentum scale is known with an uncertainty of 0.05% to 0.2% depending on rapidity. A method for the recovery of final state radiation from the muons is also presented.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2013

SWEIS Yearbook 2011: Comparison of 2011 Data to Projections of the Site-Wide Environmental Impact Statement for Continued Operation of the Los Alamos National Laboratory

Los Alamos National Laboratory (LANL) operations data for CY 2011 mostly fell within the 2008 SWEIS projections. Operation levels for four LANL facilities exceeded the 2008 SWEIS capability projections – Los Alamos Neutron Science Center (LANSCE), Solid Radioactive and Chemical Waste (SRCW), Materials Science Laboratory (MSL) and Radiochemistry Facilities. However, none of these capability increases caused exceedances in waste generation, radioactive air emissions, or NPDES discharge. Several facilities exceeded the SWEIS levels for waste generation quantities; however, all were one-time, non-routine events that do not reflect the day-to-day operations of the Laboratory. In addition, total site-wide waste generation quantities were below SWEIS projections for all waste types, reflecting the overall levels of operations at both the Key and Non-Key Facilities. Although gas and electricity consumption have remained within the 2008 SWEIS limits for utilities, water consumption exceeded the 2008 SWEIS projections by 10 million gallons in CY 2011.

Energy Conservation, Consumption, & Utilization(32↗
DOE OSTI2012

INL Seismic Monitoring Annual Report: January 1, 2011 - December 31, 2011

During 2011, the Idaho National Laboratory Seismic Monitoring Program evaluated 21,928 independent triggers that included earthquakes from around the world, the western United States, and local region of the Snake River Plain. Seismologists located 2,063 earthquakes and man-made blasts within and near the 161-km (or 100-mile) radius of the Idaho National Laboratory. Of these events, 16 were small-to-moderate size earthquakes ranging in magnitude (M) from 3.0 to 4.4. Within the 161-km radius, the majority of 941 earthquakes (M < 4.4) occurred in the active regions of the Basin and Range Province with only six microearthquakes occurring in the Snake River Plain. In the northern and southeastern Basin and Range, eight earthquake swarms occurred and included over 325 events. Five of the Snake River Plain earthquakes were located within and near the northern and southern ends of the Great Rift volcanic rift zone. All have anomalously deep focal depths (16 to 38 km) and waveforms indicative of fluid movement at mid- and lower-crustal levels and are a continuation of activity observed at Craters of the Moon National Monument since 2007. Since 1972, the Idaho National Laboratory has recorded 55 small-magnitude microearthquakes (M ≤ 2.2) within the eastern Snake River Plain and 25 deep microearthquakes (M ≤ 2.3) in the vicinity of Craters of the Moon National Monument.

58 GEOSCIENCES↗
DOE OSTI2018

Crotonaldehyde exposure in U.S. tobacco smokers and nonsmokers: NHANES 2005–2006 and 2011–2012

Highlights: • Crotonaldehyde is a potent eye, respiratory, and skin irritant. • Crotonaldehyde is a major constituent of tobacco smoke. • Exposure to crotonaldehyde can be quantified using its primary urinary metabolite HPMM. • This is the first biomonitoring evaluation of crotonaldehyde exposure in the U.S. population. • Gender, age, ethnicity, and fruit consumption are related to HPMM levels. Crotonaldehyde is an α,β-unsaturated carbonyl compound that is a potent eye, respiratory, and skin irritant. Crotonaldehyde is a major constituent of tobacco smoke and its exposure can be quantified using its urinary metabolite N-acetyl-S-(3-hydroxypropyl-1-methyl)-L-cysteine (HPMM). A large-scale biomonitoring study is needed to determine HPMM levels, as a measure of crotonaldehyde exposure, in the general U.S. population.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2012

Seismic Loading for FAST: May 2011 — August 2011

As more wind farms are constructed in seismically active regions, earthquake loading increases in prominence for design and analysis of wind turbines. Early investigation of seismic load tended to simplify the rotor and nacelle as a lumped mass on top of the turbine tower. This simplification allowed the use of techniques developed for conventional civil structures, such as buildings, to beeasily applied to wind turbines. However, interest is shifting to more detailed models that consider loads for turbine components other than the tower. These improved models offer three key capabilities in consideration of base shaking for turbines: 1) The inclusion of aerodynamics and turbine control; 2) The ability to consider component loads other than just tower loads; and 3) An improvedrepresentation of turbine response in higher modes by reducing modeling simplifications. Both experimental and numerical investigations have shown that, especially for large modern turbines, it is important to consider interaction between earthquake input, aerodynamics, and operational loads. These investigations further show that consideration of higher mode activity may be necessary in theanalysis of the seismic response of turbines. Since the FAST code is already capable of considering these factors, modifications were developed that allow simulation of base shaking. This approach allows consideration of this additional load source within a framework, the FAST code that is already familiar to many researchers and practitioners.

17 WIND ENERGY↗
NASA NTRS2012

The Origin and Evolution of Saturn's 2011-2012 Stratospheric Vortex

The planet-encircling springtime storm in Saturn's troposphere (December 2010-July 2011, Fletcher, L.N. et al. [2011]. Science 332, 1413-1414; Sánchez-Lavega, A. et al. [2011]. Nature 475, 71-74; Fischer, G. et al. [2011]. Nature 475, 75-77) produced dramatic perturbations to stratospheric temperatures, winds and composition at mbar pressures that persisted long after the tropospheric disturbance had abated. Thermal infrared (IR) spectroscopy from the Cassini Composite Infrared Spectrometer (CIRS), supported by ground-based IR imaging from the VISIR instrument on the Very Large Telescope and the MIRSI instrument on NASA's IRTF, is used to track the evolution of a large, hot stratospheric anticyclone between January 2011 and March 2012. The evolutionary sequence can be divided into three phases: (I) the formation and intensification of two distinct warm airmasses near 0.5 mbar between 25 and 35degN (B1 and B2) between January-April 2011, moving westward with different zonal velocities, B1 residing directly above the convective tropospheric storm head; (II) the merging of the warm airmasses to form the large single 'stratospheric beacon' near 40degN (B0) between April and June 2011, disassociated from the storm head and at a higher pressure (2 mbar) than the original beacons, a downward shift of 1.4 scale heights (approximately 85 km) post-merger; and (III) the mature phase characterised by slow cooling (0.11 +/- 0.01 K/day) and longitudinal shrinkage of the anticyclone since July 2011. Peak temperatures of 221.6 +/- 1.4 K at 2 mbar were measured on May 5th 2011 immediately after the merger, some 80 K warmer than the quiescent surroundings. From July 2011 to the time of writing, B0 remained as a long-lived stable stratospheric phenomenon at 2 mbar, moving west with a near-constant velocity of 2.70 +/- 0.04 deg/day (24.5 +/- 0.4 m/s at 40degN relative to System III longitudes). No perturbations to visible clouds and hazes were detected during this period. With no direct tracers of motion in the stratosphere, we use thermal windshear calculations to estimate clockwise peripheral velocities of 200-400 m/s at 2 mbar around B0. The peripheral velocities of the two original airmasses were smaller (70-140 m/s). In August 2011, the size of the vortex as defined by the peripheral collar was 65deg longitude (50,000 km in diameter) and 25deg latitude. Stratospheric acetylene (C2H2) was uniformly enhanced by a factor of three within the vortex, whereas ethane (C2H6) remained unaffected. The passage of B0 generated a new band of warm stratospheric emission at 0.5 mbar at its northern edge, and there are hints of warm stratospheric structures associated with the beacons at higher altitudes (p < 0.1 mbar) than can be reliably observed by CIRS nadir spectroscopy. Analysis of the zonal windshear suggests that Rossby wave perturbations from the convective storm could have propagated vertically into the stratosphere at this point in Saturn's seasonal cycle, one possible source of energy for the formation of these stratospheric anticyclones.

evolution↗
DOE OSTI2012

Annual Radioactive Waste Tank Inspection Program - 2011

Aqueous radioactive wastes from Savannah River Site (SRS) separations and vitrification processes are contained in large underground carbon steel tanks. Inspections made during 2011 to evaluate these vessels and other waste handling facilities along with evaluations based on data from previous inspections are the subject of this report. The 2011 inspection program revealed that the structural integrity and waste confinement capability of the Savannah River Site waste tanks were maintained. All inspections scheduled per SRR-LWE-2011-00026, HLW Tank Farm Inspection Plan for 2011, were completed. Ultrasonic measurements (UT) performed in 2011 met the requirements of C-ESR-G-00006, In-Service Inspection Program for High Level Waste Tanks, Rev. 3, and WSRC-TR-2002-00061, Rev.6. UT inspections were performed on Tanks 25, 26 and 34 and the findings are documented in SRNL-STI-2011-00495, Tank Inspection NDE Results for Fiscal Year 2011, Waste Tanks 25, 26, 34 and 41. A total of 5813 photographs were made and 835 visual and video inspections were performed during 2011. A potential leaksite was discovered at Tank 4 during routine annual inspections performed in 2011. The new crack, which is above the allowable fill level, resulted in no release to the environment or tank annulus. The location of the crack is documented in C-ESR-G-00003, SRS High Level Waste Tank Leaksite Information, Rev.6.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2012

Nevada National Security Site 2011 Waste Management Monitoring Report, Area 3 and Area 5 Radioactive Waste Management Site

Environmental monitoring data are collected at and around the Area 3 and Area 5 Radioactive Waste Management Sites (RWMSs) at the Nevada National Security Site (NNSS). These data are associated with radiation exposure, air, groundwater, meteorology, and vadose zone. This report summarizes the 2011 environmental data to provide an overall evaluation of RWMS performance and to support environmental compliance and performance assessment (PA) activities. Some of these data (e.g., radiation exposure, air, and groundwater) are presented in other reports. Direct radiation monitoring data indicate exposure levels at the RWMSs are within the range of background levels measured at the NNSS. Slightly elevated exposure levels outside the Area 3 RWMS are attributed to nearby historical aboveground nuclear weapons tests. Air monitoring data show tritium concentrations in water vapor and americium and plutonium concentrations in air particles are only slightly above detection limits and background levels. The measured levels of radionuclides in air particulates and moisture are below derived concentration guides for these radionuclides. During the last 2 weeks of March 2011, gamma spectroscopy results for air particles showed measurable activities of iodine-131 ( 131 I), cesium-134 ( 134 Cs), and cesium-137 ( 137 Cs). These results are attributed to the release of fission products from the damaged Fukushima Daiichi power plant in Japan. The remaining gamma spectroscopy results for air particulates collected at the Area 3 and Area 5 RWMS were below minimum detectable concentrations. Groundwater monitoring data indicate the groundwater in the uppermost aquifer beneath the Area 5 RWMS is not impacted by RWMS operations. Results of groundwater analysis from wells around the Area 5 RWMS were all below established investigation levels. The 86.3 millimeters (mm) (3.40 inches [in.]) of precipitation at the Area 3 RWMS during 2011 is 44% below the average of 154.1 mm (6.07 in.), and the 64.8 mm (2.55 in.) of precipitation at the Area 5 RWMS during 2011 is 47% below the average of 122.4 mm (4.82 in.). Water balance measurements indicate that evapotranspiration from the vegetated weighing lysimeter dries the soil and prevents downward percolation of precipitation more effectively than evaporation from the bare-soil weighing lysimeter. Automated vadose zone monitoring on Area 5 RWMS operational waste covers was not done during 2011 due to construction of the final evapotranspiration cover at these monitoring locations. Moisture from precipitation did not percolate below 122 centimeters (4 feet) in the vegetated final mono-layer cover on the U-3ax/bl disposal unit at the Area 3 RWMS before being removed by evapotranspiration. During 2011, there was no drainage through 2.4 meters (8 feet) of soil from the Area 3 drainage lysimeters that received only natural precipitation. Ten percent of the applied precipitation and irrigation drained from the bare-soil drainage lysimeter that received 3 times natural precipitation. All 2011 monitoring data indicate that the Area 3 and Area 5 RWMSs are performing within expectations of the model and parameter assumptions for the facility PAs.

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

Fast rotation of a subkilometer-sized near-Earth object 2011 XA{sub 3}

We present light curve observations and their multiband photometry for near-Earth object (NEO) 2011 XA{sub 3}. The light curve has shown a periodicity of 0.0304 ± 0.0003 days (= 43.8 ± 0.4 minutes). The fast rotation shows that 2011 XA{sub 3} is in a state of tension (i.e., a monolithic asteroid) and cannot be held together by self-gravitation. Moreover, the multiband photometric analysis indicates that the taxonomic class of 2011 XA{sub 3} is S-complex, or V-type. Its estimated effective diameter is 225 ± 97 m (S-complex) and 166 ± 63 m (V-type), respectively. Therefore, 2011 XA{sub 3} is a candidate for the second-largest, fast-rotating, monolithic asteroid. Moreover, the orbital parameters of 2011 XA{sub 3} are apparently similar to those of NEO (3200) Phaethon, but F/B-type. We computed the orbital evolutions of 2011 XA{sub 3} and Phaethon. However, the results of the computation and distinct taxonomy indicate that neither of the asteroids is of common origin.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2013

THE 2011 ERUPTION OF THE RECURRENT NOVA T PYXIDIS: THE DISCOVERY, THE PRE-ERUPTION RISE, THE PRE-ERUPTION ORBITAL PERIOD, AND THE REASON FOR THE LONG DELAY

We report the discovery by M. Linnolt on JD 2,455,665.7931 (UT 2011 April 14.29) of the sixth eruption of the recurrent nova T Pyxidis. This discovery was made just as the initial fast rise was starting, so with fast notification and response by observers worldwide, the entire initial rise was covered (the first for any nova), and with high time resolution in three filters. The speed of the rise peaked at 9 mag day{sup -1}, while the light curve is well fit over only the first two days by a model with a uniformly expanding sphere. We also report the discovery by R. Stubbings of a pre-eruption rise starting 18 days before the eruption, peaking 1.1 mag brighter than its long-time average, and then fading back toward quiescence 4 days before the eruption. This unique and mysterious behavior is only the fourth known (with V1500 Cyg, V533 Her, and T CrB) anticipatory rise closely spaced before a nova eruption. We present 19 timings of photometric minima from 1986 to 2011 February, where the orbital period is fast increasing with P/ P-dot =+313,000 yr. From 2008 to 2011, T Pyx had a small change in this rate of increase, so that the orbital period at the time of eruption was 0.07622950 {+-} 0.00000008 days. This strong and steady increase of the orbital period can only come from mass transfer, for which we calculate a rate of (1.7-3.5) Multiplication-Sign 10{sup -7} M{sub Sun} yr{sup -1}. We report 6116 magnitudes between 1890 and 2011, for an average B = 15.59 {+-} 0.01 from 1967 to 2011, which allows for an eruption in 2011 if the blue flux is nearly proportional to the accretion rate. The ultraviolet-optical-infrared spectral energy distribution is well fit by a power law with f{sub {nu}}{proportional_to}{nu}{sup 1.0}, although the narrow ultraviolet region has a tilt with a fit of f{sub {nu}}{proportional_to}{nu}{sup 1/3}. We prove that most of the T Pyx light is not coming from a disk, or any superposition of blackbodies, but rather is coming from some nonthermal source. We confirm the extinction measure from IUE with E(B - V) = 0.25 {+-} 0.02 mag.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2014

Causes and Implications of Extreme Atmospheric Moisture Demand during the Record-Breaking 2011 Wildfire Season in the Southwestern United States

In 2011, exceptionally low atmospheric moisture content combined with moderately high temperatures to produce a record-high vapor pressure deficit (VPD) in the southwestern United States (SW). These conditions combined with record-low cold-season precipitation to cause widespread drought and extreme wildfires. Although interannual VPD variability is generally dominated by temperature, high VPD in 2011 was also driven by a lack of atmospheric moisture. The May–July 2011 dewpoint in the SW was 4.5 standard deviations below the long-term mean. Lack of atmospheric moisture was promoted by already very dry soils and amplified by a strong ocean-to-continent sea level pressure gradient and upper-level convergence that drove dry northerly winds and subsidence upwind of and over the SW. Subsidence drove divergence of rapid and dry surface winds over the SW, suppressing southerly moisture imports and removing moisture from already dry soils. Model projections developed for the fifth phase of the Coupled Model Intercomparison Project (CMIP5) suggest that by the 2050s warming trends will cause mean warm-season VPD to be comparable to the record-high VPD observed in 2011. CMIP5 projections also suggest increased interannual variability of VPD, independent of trends in background mean levels, as a result of increased variability of dewpoint, temperature, vapor pressure, and saturation vapor pressure. Increased variability in VPD translates to increased probability of 2011-type VPD anomalies, which would be superimposed on ever-greater background VPD levels. Although temperature will continue to be the primary driver of interannual VPD variability, 2011 served as an important reminder that atmospheric moisture content can also drive impactful VPD anomalies.

54 ENVIRONMENTAL SCIENCES↗