12,194 research outputs found
Wind profiler demonstration system
The National Oceanic and Atmospheric Administration (NOAA) has started procurement of a 30-station demonstration network of Doppler radar wind profilers to be deployed in the central United States by 1989. The purposes of this demonstration network are: (1) to assess the impact of a large wind profiler network on meteorological forecasting; (2) to test wind profiler hardware designed specifically for commercial production and widespread deployment; and (3) to provide wind data for research programs involving weather phenomena in the central United States
Operating manual for coaxial injection combustion model
An operating manual for the coaxial injection combustion model (CICM) is presented as the final report for an eleven month effort designed to provide improvement, to verify, and to document the comprehensive computer program for analyzing the performance of thrust chamber operation with gas/liquid coaxial jet injection. The effort culminated in delivery of an operation FORTRAN IV computer program and associated documentation pertaining to the combustion conditions in the space shuttle main engine. The computer program is structured for compatibility with the standardized Joint Army-Navy-NASA-Air Force (JANNAF) performance evaluation procedure. Use of the CICM in conjunction with the JANNAF procedure allows the analysis of engine systems using coaxial gas/liquid injection
Near Infrared Surface Properties of the Two Intrinsically Brightest Minor Planets (90377) Sedna and (90482) Orcus
We present low resolution K band spectra taken at the Gemini 8 meter
telescope of (90377) Sedna and (90482) Orcus (provisional designations 2003
VB12 and 2004 DW, respectively), currently the two minor planets with the
greatest absolute magnitudes (i.e. the two most reflective minor planets). We
place crude limits on the surface composition of these two bodies using a Hapke
model for a wide variety of assumed albedos. The unusual minor planet (90377)
Sedna was discovered on November 14, 2003 UT at roughly 90 AU with 1.6 times
the heliocentric distance and perihelion distance of any other bound minor
planet. It is the first solar system object discovered between the Kuiper Belt
and the Oort Cloud, and may represent a transition population between the two.
The reflectance spectrum of (90377) Sedna appears largely featureless at the
current signal-to-noise ratio, suggesting a surface likely to be highly
processed by cosmic rays. For large grain models (100 micron to 1 cm) we find
that (90377) Sedna must have less than 70% surface fraction of water ice and
less than 60% surface fraction of methane ice to 3 sigma confidence. Minor
planet (90482) Orcus shows strong water ice absorption corresponding to less
than 50% surface fraction for grain models 25 micron and larger. Orcus cannot
have more than 30% of its surface covered by large (100 mm to 1 cm) methane
grains to 3 sigma confidence.Comment: Accepted for publication in the Astrophysical Journa
Strategies to reduce nutrient pollution from manure management in China
As the demand for livestock products continues to increase in China, so too does the challenge of managing increasing quantities of manure. Urgent action is needed to control point source (housing, storage and processing) and diffuse (field application) pollution and improve the utilization of manure nutrients and organic matter. Here, we review strategies to improve management at each stage of the manure management chain and at different scales. Many strategies require infrastructure investment, e.g., for containment of all manure fractions. Engineering solutions are needed to develop advanced composting systems with lower environmental footprints and design more efficient nutrient stripping technologies. At the field-scale, there is an urgent need to develop a manure nutrient recommendation system that accounts for the range of manure types, cropping systems, soils and climates throughout China. At the regional scale, coordinated planning is necessary to promote recoupling of livestock and cropping systems, and reduce nutrient accumulation in regions with little available landbank, while minimizing the risk of pollution swapping from one region to another. A range of stakeholders are needed to support the step change and innovation required to improve manure management, reduce reliance on inorganic fertilizers, and generate new business opportunities
Underground CO2 storage: demonstrating regulatory conformance by convergence of history-matched modeled and observed CO2 plume behavior using Sleipner time-lapse seismics
One of the three key regulatory requirements in Europe for transfer of storage site liability is to demonstrate conformity between predictive models of reservoir performance and monitoring observations. This is a challenging requirement because a perfect and unique match between observed and modeled behavior is near impossible to achieve. This study takes the time-lapse seismic monitoring data from the Sleipner storage operation to demonstrate that as more seismic data becomes available with time, predictive models can be matched more accurately to observations and become more reliable predictors of future performance. Six simple performance measures were defined: plume footprint area, maximum lateral migration distance of CO2 from the injection point, area of CO2 accumulation trapped at top reservoir, volume of CO2 accumulation trapped at top reservoir, area of all CO2 layers summed, and spreading co-efficient. Model scenarios were developed to predict plume migration up to 2008. Scenarios were developed for 1996 (baseline), 2001, and 2006 conditions, with models constrained by the information available at those times, and compared with monitoring datasets obtained up to 2008. The 1996 predictive range did generally encompass the future observed plume behavior, but with such a wide range of uncertainty as to render it of only marginal practical use. The 2001 predictions (which used the 1999 and 2001 seismic monitoring datasets) had a much lower uncertainty range, with the 2006 uncertainties somewhat lower again. There are still deficiencies in the actual quality of match but a robust convergence, with time, of predicted and observed models is clearly demonstrated. We propose modeling-monitoring convergence as a generic approach to demonstrating conformance
Land-ocean shifts in tropical precipitation linked to surface temperature and humidity change
This is the final version of the article. Available from American Meteorological Society via the DOI in this record.A compositing scheme that predicts changes in tropical precipitation under
climate change from changes in near-surface relative humidity (RH) and
temperature is presented. As shown by earlier work, regions of high tropical
precipitation in general circulation models (GCMs) are associated with high
near-surface RH and temperature. Under climate change, we find that high
precipitation continues to be associated with the highest surface RH and temperatures
in most CMIP5 GCMs, meaning that it is the “rank” of a given GCM
gridbox with respect to others that determines how much precipitation falls
rather than the absolute value of surface temperature or RH change, consistent
with the weak temperature gradient approximation. Further, we demonstrate
that the majority of CMIP5 GCMs are close to a threshold near which
reductions in land RH produce large reductions in the RH-ranking of some
land regions, causing reductions in precipitation over land, particularly South
America, and compensating increases over ocean. Recent work on predicting
future changes in specific humidity allows us to predict the qualitative sense of
precipitation change in some GCMs when land surface humidity changes are
unknown. However, the magnitudes of predicted changes are too small. Further
study, perhaps into the role of radiative and land-atmosphere feedbacks
that we neglect, is necessary.We are grateful to Richard Allan, whose suggestions substantially improved
results. We acknowledge the World Climate Research Programmes Working Group on Coupled
Modelling, which is responsible for CMIP, and we thank the climate modeling groups (listed in
Table 1) for producing and making available their model output. For CMIP the U.S. Department of
Energy’s Program for Climate Model Diagnosis and Intercomparison provides coordinating sup-
port and led development of software infrastructure in partnership with the Global Organization
for Earth System Science Portals. We thank the JASMIN and CEDA team for making available the
JASMIN computing resource (Lawrence et al. 2013). FHL was part supported by the UK-China
Research & Innovation Partnership Fund through the Met Office Climate Science for Service Part-
nership (CSSP) China as part of the Newton Fund; AJF was supported by the NERC PROBEC
project NE/K016016/1; RC was supported by the Newton Fund through the Met Office CSSP
Brazi
7-Li(p,n) Nuclear Data Library for Incident Proton Energies to 150 MeV
We describe evaluation methods that make use of experimental data, and
nuclear model calculations, to develop an ENDF-formatted data library for the
reaction p + Li7 for incident protons with energies up to 150 MeV. The
important 7-Li(p,n_0) and 7-Li(p,n_1) reactions are evaluated from the
experimental data, with their angular distributions represented using Lengendre
polynomial expansions. The decay of the remaining reaction flux is estimated
from GNASH nuclear model calculations. The evaluated ENDF-data are described in
detail, and illustrated in numerous figures. We also illustrate the use of
these data in a representative application by a radiation transport simulation
with the code MCNPX.Comment: 11 pages, 8 figures, LaTeX, submitted to Proc. 2000 ANS/ENS
International Meeting, Nuclear Applications of Accelerator Technology
(AccApp00), November 12-16, Washington, DC, US
Critical review of the impacts of grazing intensity on soil organic carbon storage and other soil quality indicators in extensively managed grasslands
Acknowledgements This work contributes to the N-Circle project (grant number BB/N013484/1), and CINAg (BB/N013468/1) Virtual Joint Centres on Agricultural Nitrogen (funded by the Newton Fund via UK BBSRC/NERC), U-GRASS (grant number NE/M016900/1), the Belmont Forum/FACCE-JPI DEVIL project (grant number NE/M021327/1), Soils-R-GGREAT (grant number NE/P019455/1), ADVENT (grant number NE/M019713/1), Sêr Cymru LCEE-NRN project, Climate-Smart Grass and the Scottish Government’s Strategic Research Programme.Peer reviewedPublisher PD
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