321 research outputs found
WHOI Hawaii Ocean Timeseries Station (WHOTS) : WHOTS-6 2009 mooring turnaround cruise report
The Woods Hole Oceanographic Institution (WHOI) Hawaii Ocean Timeseries Site
(WHOTS), 100 km north of Oahu, Hawaii, is intended to provide long-term, high-quality air-sea
fluxes as a part of the NOAA Climate Observation Program. The WHOTS mooring also serves
as a coordinated part of the Hawaiian Ocean Timeseries (HOT) program, contributing to the
goals of observing heat, fresh water and chemical fluxes at a site representative of the
oligotrophic North Pacific Ocean. The approach is to maintain a surface mooring outfitted for
meteorological and oceanographic measurements at a site near 22.75°N, 158°W by successive
mooring turnarounds. These observations will be used to investigate air–sea interaction processes
related to climate variability.
The first WHOTS mooring (WHOTS-1) was deployed in August 2004. Turnaround cruises for
successive moorings (WHOTS-2 through WHOTS-5) have typically been in either June or July.
This report documents recovery of the WHOTS-5 mooring and deployment of the sixth mooring
(WHOTS-6). The moorings utilize Surlyn foam buoys as the surface element and are outfitted
with two Air–Sea Interaction Meteorology (ASIMET) systems. Each ASIMET system measures,
records, and transmits via Argos satellite the surface meteorological variables necessary to
compute air–sea fluxes of heat, moisture and momentum. The upper 155 m of the mooring is
outfitted with oceanographic sensors for the measurement of temperature, conductivity and
velocity in a cooperative effort with R. Lukas of the University of Hawaii (UH). A pCO2 system
is installed on the buoy in a cooperative effort with Chris Sabine at the Pacific Marine
Environmental Laboratory. Dr. Frank Bradley, CSIRO, Australia, assisted with meteorological
sensor comparisons. A NOAA “Teacher at Sea” and a NOAA “Teacher in the Lab” participated
in the cruise.
The WHOTS mooring turnaround was done on the University of Hawaii research vessel
Kilo Moana, Cruise KM-09-16, by the Upper Ocean Processes Group of the Woods Hole
Oceanographic Institution in cooperation with UH and NOAA’s Earth System Research
Laboratory, Physical Sciences Division (ESRL/PSD). The cruise took place between 9 and 17
July 2009. Operations began with deployment of the WHOTS-6 mooring on 10 July at
approximately 22°40.0'N, 157°57.0'W in 4758 m of water. This was followed by meteorological
intercomparisons and CTDs at the WHOTS-6 and WHOTS-5 sites. The WHOTS-5 mooring was
recovered on 15 July 2009. The Kilo Moana then moved to the HOT central site (22°45.0'N,
158°00.0'W) for CTD casts. This report describes the cruise operations in more detail, as well as
some of the in-port operations and pre-cruise buoy preparations.Funding was provided by the National Oceanic and Atmospheric Administration
under Grant No. NA17RJ1223 for the Cooperative Institute for Climate and Ocean Research (CICOR)
Stratus 9/VOCALS ninth setting of the Stratus Ocean Reference Station & VOCALS Regional Experiment
The Ocean Reference Station at 20°S, 85°W under the stratus clouds west of northern Chile is
being maintained to provide ongoing climate-quality records of surface meteorology; air-sea
fluxes of heat, freshwater, and momentum; and of upper ocean temperature, salinity, and velocity
variability. The Stratus Ocean Reference Station (ORS Stratus) is supported by the National
Oceanic and Atmospheric Administration’s (NOAA) Climate Observation Program. It is
recovered and redeployed annually, with cruises that have come between October and December.
During the 2008 cruise on the NOAA ship Ronald H. Brown to the ORS Stratus site, the primary
activities were recovery of the Stratus 8 WHOI surface mooring that had been deployed in
October 2007, deployment of a new (Stratus 9) WHOI surface mooring at that site; in-situ
calibration of the buoy meteorological sensors by comparison with instrumentation put on board
by staff of the NOAA Earth System Research Laboratory (ESRL); and observations of the stratus
clouds and lower atmosphere by NOAA ESRL. A buoy for the Pacific tsunami warning system
was also serviced in collaboration with the Hydrographic and Oceanographic Service of the
Chilean Navy (SHOA). The DART (Deep-Ocean Assessment and Reporting of Tsunami) carries
IMET sensors and subsurface oceanographic instruments. A DART II buoy was deployed north
of the STRATUS buoy, by personnel from the National Data Buoy Center (NDBC)
Argo floats and drifters were launched, and CTD casts carried out during the cruise.
The ORS Stratus buoys are equipped with two Improved Meteorological (IMET) systems, which
provide surface wind speed and direction, air temperature, relative humidity, barometric
pressure, incoming shortwave radiation, incoming longwave radiation, precipitation rate, and sea
surface temperature. Additionally, the Stratus 8 buoy received a partial CO2 detector from the
Pacific Marine Environmental Laboratory (PMEL). IMET data are made available in near real
time using satellite telemetry. The mooring line carries instruments to measure ocean salinity,
temperature, and currents.
The ESRL instrumentation used during the 2008 cruise included cloud radar, radiosonde
balloons, and sensors for mean and turbulent surface meteorology.
Finally, the cruise hosted a teacher participating in NOAA’s Teacher at Sea Program.Funding was provided by the National Oceanic and Atmospheric Administration
under Grant No. NA17RJ1223 for the Cooperative Institute for Climate and Ocean Research (CICOR)
Economic Stress and the Great Recession in Ireland: Polarization, Individualization or ‘Middle Class Squeeze’?
Upper limits on the strength of periodic gravitational waves from PSR J1939+2134
The first science run of the LIGO and GEO gravitational wave detectors
presented the opportunity to test methods of searching for gravitational waves
from known pulsars. Here we present new direct upper limits on the strength of
waves from the pulsar PSR J1939+2134 using two independent analysis methods,
one in the frequency domain using frequentist statistics and one in the time
domain using Bayesian inference. Both methods show that the strain amplitude at
Earth from this pulsar is less than a few times .Comment: 7 pages, 1 figure, to appear in the Proceedings of the 5th Edoardo
Amaldi Conference on Gravitational Waves, Tirrenia, Pisa, Italy, 6-11 July
200
Improving the sensitivity to gravitational-wave sources by modifying the input-output optics of advanced interferometers
We study frequency dependent (FD) input-output schemes for signal-recycling
interferometers, the baseline design of Advanced LIGO and the current
configuration of GEO 600. Complementary to a recent proposal by Harms et al. to
use FD input squeezing and ordinary homodyne detection, we explore a scheme
which uses ordinary squeezed vacuum, but FD readout. Both schemes, which are
sub-optimal among all possible input-output schemes, provide a global noise
suppression by the power squeeze factor, while being realizable by using
detuned Fabry-Perot cavities as input/output filters. At high frequencies, the
two schemes are shown to be equivalent, while at low frequencies our scheme
gives better performance than that of Harms et al., and is nearly fully
optimal. We then study the sensitivity improvement achievable by these schemes
in Advanced LIGO era (with 30-m filter cavities and current estimates of
filter-mirror losses and thermal noise), for neutron star binary inspirals, and
for narrowband GW sources such as low-mass X-ray binaries and known radio
pulsars. Optical losses are shown to be a major obstacle for the actual
implementation of these techniques in Advanced LIGO. On time scales of
third-generation interferometers, like EURO/LIGO-III (~2012), with
kilometer-scale filter cavities, a signal-recycling interferometer with the FD
readout scheme explored in this paper can have performances comparable to
existing proposals. [abridged]Comment: Figs. 9 and 12 corrected; Appendix added for narrowband data analysi
Search for gravitational wave bursts in LIGO's third science run
We report on a search for gravitational wave bursts in data from the three
LIGO interferometric detectors during their third science run. The search
targets subsecond bursts in the frequency range 100-1100 Hz for which no
waveform model is assumed, and has a sensitivity in terms of the
root-sum-square (rss) strain amplitude of hrss ~ 10^{-20} / sqrt(Hz). No
gravitational wave signals were detected in the 8 days of analyzed data.Comment: 12 pages, 6 figures. Amaldi-6 conference proceedings to be published
in Classical and Quantum Gravit
Differential limit on the extremely-high-energy cosmic neutrino flux in the presence of astrophysical background from nine years of IceCube data
We report a quasi-differential upper limit on the extremely-high-energy (EHE)
neutrino flux above GeV based on an analysis of nine years of
IceCube data. The astrophysical neutrino flux measured by IceCube extends to
PeV energies, and it is a background flux when searching for an independent
signal flux at higher energies, such as the cosmogenic neutrino signal. We have
developed a new method to place robust limits on the EHE neutrino flux in the
presence of an astrophysical background, whose spectrum has yet to be
understood with high precision at PeV energies. A distinct event with a
deposited energy above GeV was found in the new two-year sample, in
addition to the one event previously found in the seven-year EHE neutrino
search. These two events represent a neutrino flux that is incompatible with
predictions for a cosmogenic neutrino flux and are considered to be an
astrophysical background in the current study. The obtained limit is the most
stringent to date in the energy range between and GeV. This result constrains neutrino models predicting a three-flavor
neutrino flux of $E_\nu^2\phi_{\nu_e+\nu_\mu+\nu_\tau}\simeq2\times 10^{-8}\
{\rm GeV}/{\rm cm}^2\ \sec\ {\rm sr}10^9\ {\rm GeV}$. A significant part
of the parameter-space for EHE neutrino production scenarios assuming a
proton-dominated composition of ultra-high-energy cosmic rays is excluded.Comment: The version accepted for publication in Physical Review
The Baryon Oscillation Spectroscopic Survey of SDSS-III
The Baryon Oscillation Spectroscopic Survey (BOSS) is designed to measure the
scale of baryon acoustic oscillations (BAO) in the clustering of matter over a
larger volume than the combined efforts of all previous spectroscopic surveys
of large scale structure. BOSS uses 1.5 million luminous galaxies as faint as
i=19.9 over 10,000 square degrees to measure BAO to redshifts z<0.7.
Observations of neutral hydrogen in the Lyman alpha forest in more than 150,000
quasar spectra (g<22) will constrain BAO over the redshift range 2.15<z<3.5.
Early results from BOSS include the first detection of the large-scale
three-dimensional clustering of the Lyman alpha forest and a strong detection
from the Data Release 9 data set of the BAO in the clustering of massive
galaxies at an effective redshift z = 0.57. We project that BOSS will yield
measurements of the angular diameter distance D_A to an accuracy of 1.0% at
redshifts z=0.3 and z=0.57 and measurements of H(z) to 1.8% and 1.7% at the
same redshifts. Forecasts for Lyman alpha forest constraints predict a
measurement of an overall dilation factor that scales the highly degenerate
D_A(z) and H^{-1}(z) parameters to an accuracy of 1.9% at z~2.5 when the survey
is complete. Here, we provide an overview of the selection of spectroscopic
targets, planning of observations, and analysis of data and data quality of
BOSS.Comment: 49 pages, 16 figures, accepted by A
- …