620 research outputs found
Infrared measurements of atmospheric constituents
The objective of this program is to obtain data concerning the concentration versus altitude of various constituents of interest in the photochemistry of the stratospheric ozone layer. Data pertinent to this objective are obtained using balloon-borne instruments to measure the atmospheric transmission and emission in the mid infrared. In addition to obtaining constituent profile information, the spectral data obtained are also used to identify absorption or emission features which may interfere with the retrieval of constituent data from satellite instruments using lower spectral resolution. The spectral resolution obtained with the solar spectral system is 0.0025 cm(exp -1) and represents about a factor of 5 greater resolution than any solar spectra previously obtained in this spectral region. As a result of the increase in spectral resolution, a large number of features are observed in these spectra which were not observed in previous studies. Identification and analysis of these features is in progress. The results of this analysis to date shows a number of HNO3 features which have not been observed before, and these occur where they will interfere with the retrieval of other constituents. An example of the interference is the occurrence of features in the 780.2 cm(exp -1) region which overlap the ClONO2 feature which will be used for retrieval of ClONO2 by the CLAES instrument on UARS. A number of features due to COF2 were also identified in the 1250 cm(exp -1) region which may interfere with retrieval of N2O5
Traveling Wave Fronts and Localized Traveling Wave Convection in Binary Fluid Mixtures
Nonlinear fronts between spatially extended traveling wave convection (TW)
and quiescent fluid and spatially localized traveling waves (LTWs) are
investigated in quantitative detail in the bistable regime of binary fluid
mixtures heated from below. A finite-difference method is used to solve the
full hydrodynamic field equations in a vertical cross section of the layer
perpendicular to the convection roll axes. Results are presented for
ethanol-water parameters with several strongly negative separation ratios where
TW solutions bifurcate subcritically. Fronts and LTWs are compared with each
other and similarities and differences are elucidated. Phase propagation out of
the quiescent fluid into the convective structure entails a unique selection of
the latter while fronts and interfaces where the phase moves into the quiescent
state behave differently. Interpretations of various experimental observations
are suggested.Comment: 46 pages, 11 figures. Accepted for publication in Phys. Rev.
Chemical ozone loss in the Arctic winter 1991â1992
Chemical ozone loss in winter 1991â1992 is recalculated based on observations of the HALOE satellite instrument, Version 19, ER-2 aircraft measurements and balloon data. HALOE satellite observations are shown to be reliable in the lower stratosphere below 400 K, at altitudes where the measurements are most likely disturbed by the enhanced sulfate aerosol loading, as a result of the Mt.~Pinatubo eruption in June 1991. Significant chemical ozone loss (13â17 DU) is observed below 380 K from Kiruna balloon observations and HALOE satellite data between December 1991 and March 1992. For the two winters after the Mt. Pinatubo eruption, HALOE satellite observations show a stronger extent of chemical ozone loss towards lower altitudes compared to other Arctic winters between 1991 and 2003. In spite of already occurring deactivation of chlorine in March 1992, MIPAS-B and LPMA balloon observations indicate that chlorine was still activated at lower altitudes, consistent with observed chemical ozone loss occurring between February and March and April. Large chemical ozone loss of more than 70 DU in the Arctic winter 1991â1992 as calculated in earlier studies is corroborated here
Bromine in the tropical troposphere and stratosphere as derived from balloon-borne BrO observations
The first tropospheric and stratospheric (4 to 33 km) BrO profile is presented for the inner tropics derived from balloon-borne DOAS (Differential Optical Absorption Spectroscopy) measurements. In combination with photochemical modelling, total stratospheric inorganic bromine (Br<sub>y</sub>) is deduced to be (21.5&plusmn;2.5) ppt in 4.5-year-old air, probed in 2005. We derive a total contribution of (5.2&plusmn;2.5) ppt from brominated very short-lived substances and inorganic product gases to stratospheric Br<sub>y</sub> Tropospheric BrO was found to be <1 ppt. Our results are compared to two 3-D CTM SLIMCAT model runs, which differ in the lifetime of the bromine source gases, affecting the vertical distribution of Br<sub>y</sub> in the lower stratosphere. Bromine source gas measurements performed 10 days earlier Laube et al., 2008, indicate a lower Br<sub>y</sub> of (17.5&plusmn;0.4) ppt. Potential reasons for this discrepancy are discussed
AZ ĂLELMISZERGAZDASĂG KĂLKERESKEDELME 2016. Ă©v IâX. hĂłnap
A mezĆgazdasĂĄgi Ă©s Ă©lelmiszeripari termĂ©kek kivitele 6607 milliĂł eurĂłt, behozatala 4216 milliĂł eurĂłt tett ki 2016 elsĆ tĂz hĂłnapjĂĄban. Az agrĂĄr-kĂŒlkereskedelmi forgalom 2391 milliĂł eurĂł aktĂvumot eredmĂ©nyezett. A kivitel Ă©rtĂ©ke 1,4 szĂĄzalĂ©kkal, a behozatalĂ© 4,8 szĂĄzalĂ©kkal emelkedett, az aktĂvum 4,1 szĂĄzalĂ©kkal, 103 milliĂł eurĂłval elmaradt a 2015. januĂĄrâoktĂłberi Ă©rtĂ©ktĆl. A mezĆgazdasĂĄgi Ă©s Ă©lelmiszeripari termĂ©kek rĂ©szesedĂ©se a teljes nemzetgazdasĂĄgi exportbĂłl 2016 oktĂłberĂ©ben 8,9 szĂĄzalĂ©k, 2016 januĂĄrâoktĂłberi idĆszakĂĄban 8,5 szĂĄzalĂ©k, az importbĂłl 2016 oktĂłberĂ©ben 6,3 szĂĄzalĂ©k, 2016 januĂĄrâoktĂłberi idĆszakĂĄban 6,1 szĂĄzalĂ©k volt. Az agrĂĄrexport arĂĄnya 2016 januĂĄrâoktĂłberi idĆszakĂĄban 0,1 szĂĄzalĂ©kponttal alacsonyabb, mĂg az import arĂĄnya 0,2 szĂĄzalĂ©kponttal magasabb volt, mint 2015 elsĆ tĂz hĂłnapjĂĄban
Intermittency of Height Fluctuations and Velocity Increment of The Kardar-Parisi-Zhang and Burgers Equations with infinitesimal surface tension and Viscosity in 1+1 Dimensions
The Kardar-Parisi-Zhang (KPZ) equation with infinitesimal surface tension,
dynamically develops sharply connected valley structures within which the
height derivative is not continuous. We discuss the intermittency issue in the
problem of stationary state forced KPZ equation in 1+1--dimensions. It is
proved that the moments of height increments behave as with for length scales . The length scale is the characteristic length of the
forcing term. We have checked the analytical results by direct numerical
simulation.Comment: 13 pages, 9 figure
Vortex disruption by magnetohydrodynamic feedback
In an electrically conducting fluid, vortices stretch out a weak, large-scale magnetic field to form strong current sheets on their edges. Associated with these current sheets are magnetic stresses, which are subsequently released through reconnection, leading to vortex disruption, and possibly even destruction. This disruption phenomenon is investigated here in the context of two-dimensional, homogeneous, incompressible magnetohydrodynamics. We derive a simple order of magnitude estimate for the magnetic stressesâand thus the degree of disruptionâthat depends on the strength of the background magnetic field (measured by the parameter M, a ratio between the AlfvĂ©n speed and a typical flow speed) and on the magnetic diffusivity (measured by the magnetic Reynolds number Rm). The resulting estimate suggests that significant disruption occurs when MÂČRm=O(1). To test our prediction, we analyze direct numerical simulations of vortices generated by the breakup of unstable shear flows with an initially weak background magnetic field. Using the Okubo-Weiss vortex coherence criterion, we introduce a vortex disruption measure, and show that it is consistent with our predicted scaling, for vortices generated by instabilities of both a shear layer and a jet
Technical note: First spectral measurement of the Earth's upwelling emission using an uncooled wideband Fourier transform spectrometer
The first spectral measurement of Earth's emitted radiation to space in the wideband range from 100 to 1400 cm<sup>−1</sup> with 0.5 cm<sup>−1</sup> spectral resolution is presented. The measurement was performed from a stratospheric balloon in tropical region using a Fourier transform spectrometer, during a field campaign held in Brazil in June 2005. The instrument, which has uncooled components including the detector module, is a prototype developed as part of the study for the REFIR (Radiation Explorer in the Far InfraRed) space mission. This paper shows the results of the field campaign with particular attention to the measurement capabilities of the prototype. The results are compared with measurements taken by IASI-balloon (Infrared Atmospheric Sounding Interferometer – Balloon version), aboard the same platform, and with forward model estimations. The infrared signature of clouds is observed in the measurements
A Method for Calculating the Structure of (Singular) Spacetimes in the Large
A formalism and its numerical implementation is presented which allows to
calculate quantities determining the spacetime structure in the large directly.
This is achieved by conformal techniques by which future null infinity
(\Scri{}^+) and future timelike infinity () are mapped to grid points on
the numerical grid. The determination of the causal structure of singularities,
the localization of event horizons, the extraction of radiation, and the
avoidance of unphysical reflections at the outer boundary of the grid, are
demonstrated with calculations of spherically symmetric models with a scalar
field as matter and radiation model.Comment: 29 pages, AGG2
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