53 research outputs found
Chesapeake Bay Watershed Model Application and Calculation Of Nutrient and Sediment Loadings. Appendix H: Tracking Best Management Practice Nutrient Reductions in the Chesapeake Bay Program
Seasonal and intra-diurnal variability of small-scale gravity waves in OH airglow at two Alpine stations
Between December 2013 and August 2017 the instrument FAIM (Fast Airglow
IMager) observed the OH airglow emission at two Alpine stations. A year of
measurements was performed at Oberpfaffenhofen, Germany (48.09∘ N,
11.28∘ E) and 2 years at Sonnblick, Austria (47.05∘ N,
12.96∘ E). Both stations are part of the network for the detection
of mesospheric change (NDMC). The temporal resolution is two frames per
second and the field-of-view is 55 km × 60 km and
75 km × 90 km at the OH layer altitude of 87 km with a spatial
resolution of 200 and 280 m per pixel, respectively. This resulted in two
dense data sets allowing precise derivation of horizontal gravity wave
parameters. The analysis is based on a two-dimensional fast Fourier transform
with fully automatic peak extraction. By combining the information of
consecutive images, time-dependent parameters such as the horizontal phase
speed are extracted. The instrument is mainly sensitive to high-frequency
small- and medium-scale gravity waves. A clear seasonal dependency concerning
the meridional propagation direction is found for these waves in summer in
the direction to the summer pole. The zonal direction of propagation is
eastwards in summer and westwards in winter. Investigations of the data set
revealed an intra-diurnal variability, which may be related to tides. The
observed horizontal phase speed and the number of wave events per
observation hour are higher in summer than in winter.</p
Discovery of the Cadmium Isotopes
Thirty-seven cadmium isotopes have so far been observed; the discovery of
these isotopes is discussed. For each isotope a brief summary of the first
refereed publication, including the production and identification method, is
presented.Comment: to be published in Atomic Data and Nuclear Data Table
Selective laser ionization of N 82 indium isotopes: the new r-process nuclide In
Production yields and beta-decay half-lives of very neutron-rich indium isotopes were determined at CERN/ISOLDE using isobaric selectivity of a resonance-ionization laser ion-source. Beta-delayed neutron multiscaling measurements have yielded improved half-lives for 206(6)~ms In, 165(3)~ms In and 141(5)~ms In. With 92(10)~ms In, a new r-process nuclide has been identified which acts as an important `waiting-point' in the In isotopic chain for neutron densities in the range n--10 n/cm, where the r-matter flow has already passed the abundance-peak region
Observations of OH airglow from ground, aircraft, and satellite: investigation of wave-like structures before a minor stratospheric warming
In January and February 2016, the OH airglow camera system FAIM (Fast Airglow
Imager) measured during six flights on board the research aircraft FALCON in
northern Scandinavia. Flight 1 (14 January 2016) covering the same ground
track in several flight legs and flight 5 (28 January 2016) along the
shoreline of Norway are discussed in detail in this study. The images of the
OH airglow intensity are analysed with a two-dimensional FFT regarding
horizontal periodic structures between 3 and 26 km horizontal wavelength and
their direction of propagation. Two ground-based spectrometers (GRIPS,
Ground-based Infrared P-branch Spectrometer) provided OH airglow
temperatures. One was placed at ALOMAR, Northern Norway (Arctic Lidar
Observatory for Middle Atmosphere Research; 69.28∘ N,
16.01∘ E) and the other one at Kiruna, northern Sweden
(67.86∘ N, 20.24∘ E). Especially during the last third of
January 2016, the weather conditions at Kiruna were good enough for the
computation of nightly means of gravity wave potential energy density.
Coincident TIMED-SABER (Thermosphere Ionosphere Mesosphere Energetics
Dynamics–Sounding of the Atmosphere using Broadband Emission Radiometry)
measurements complete the data set. They allow for the derivation of
information about the Brunt–Väisälä frequency and about the
height of the OH airglow layer as well as its thickness.
The data are analysed with respect to the temporal and spatial evolution of
mesopause gravity wave activity just before a minor stratospheric warming at
the end of January 2016. Wave events with periods longer (shorter) than
60 min might mainly be generated in the troposphere (at or above the height
of the stratospheric jet). Special emphasis is placed on small-scale
signatures, i.e. on ripples, which may be signatures of local instability
and which may be related to a step in a wave-breaking process. The most
mountainous regions are characterized by the highest occurrence rate of
wave-like structures in both flights.</p
Decay of neutron-rich Mn nuclides and deformation of heavy Fe isotopes
The use of chemically selective laser ionization combined with beta-delayed neutron counting at CERN/ISOLDE has permitted identification and half-life measurements for 623-ms Mn-61 up through 14-ms Mn-69. The measured half-lives are found to be significantly longer near N=40 than the values calculated with a QRPA shell model using ground-state deformations from the FRDM and ETFSI models. Gamma-ray singles and coincidence spectroscopy has been performed for Mn-64 and Mn-66 decays to levels of Fe-64 and Fe-66, revealing a significant drop in the energy of the first 2+ state in these nuclides that suggests an unanticipated increase in collectivity near N=40
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