bluuebunny/crossref_metadata_2025_split huggingface dataset:
The sensitivity of simulated orographic precipitation to model components other than cloud microphysics
Authors: Zängl G. 
Published: July 2004

AbstractNumerical simulations of an orographic precipitation event observed during the MAP field phase are presented in order to investigate side effects on the simulated precipitation. The simulations are conducted with the Penn State University—National Center for Atmospheric Research mesoscale model MM5 in a configuration with four interactively nested domains and a finest grid spacing of 1.4 km. The sensitivity tests examine the impact of the boundary‐layer parametrization, the set‐up of the convection parametrizations in the outer model domains, the implementation of the horizontal diffusion and the specification of the vertical coordinate. For reference, five different cloud microphysical parametrizations are compared against each other.The results show that each of the side effects arising from the model numerics and from the physics parametrizations not related to cloud microphysics can be as large as, or even larger than, the impact of the microphysical parametrization itself. A particularly large sensitivity is found for the horizontal diffusion of temperature and moisture. Computing this diffusion along the terrain‐following coordinate surfaces rather than truly horizontally increases the average precipitation in the 1.4 km domain by about 35%, and a comparison with surface observations indicates a pronounced deterioration of the model results. The other sensitivities are found to range between 10% and 15% on a domain average. An important conclusion emanating from these results is that future model development should pay much more attention to the cross‐sensitivities between the model numerics, the convection and boundary‐layer parametrizations and the cloud microphysical parametrization. Copyright © 2004 Royal Meteorological Society.
Oxidized nitrogen and ozone interaction with forests. I: Experimental observations and analysis of exchange with Douglas fir
Authors: Dorsey J. R. , Duyzer J. H. , Gallagher M. W. , Coe H. , Pilegaard K. , Weststrate J. H. , Jensen N. O. , Walton S. 
Published: July 2004

AbstractMeasurements of NOx and O3 exchange to and from a forest canopy are described with reference to canopy and ecosystem processes leading to emission of NO2. The soil below the forested measurement location is shown to be a net source of reactive oxidized nitrogen (as NO). It is shown that a large fraction (around 58% on average) of the emitted NO escapes out of the trunk space to react within and above the canopy.Fluxes of NO2 above the canopy are bi‐directional, with large fluxes and most emission events taking place during the day. Deposition is shown to take place without significant changes in the vertical flux; however there appears to be rapid chemical reaction leading to significant flux divergence taking place during emission events. Above the top of the canopy (22 m), changes of 200% in the NO2 flux between 25 and 35 m are not uncommon.Ozone deposition to the forest system has been investigated. The flux is often related to stomatal deposition, but there are periods when large non‐stomatal fluxes are observed. At night there is a large vertical divergence in the ozone flux above the canopy, probably related to reaction with NO from the forest soil. The reaction of O3 with volatile organic compounds is found, in general, to be negligible with respect to ozone concentrations and fluxes.Ozone is found to deposit mainly to leaf stomata during the day, with a small but not insignificant contribution from NO reaction. However, the nocturnal ozone budget for the forest changes significantly, with most of the measured deposition accounted for by soil uptake and reaction with NO. The resultant problems related to inadequate treatment of air chemistry when interpreting O3 fluxes in high NO emission environments are identified. Copyright © 2004 Royal Meteorological Society.
Oxidized nitrogen and ozone interaction with forests. II: Multi‐layer process‐oriented modelling results and a sensitivity study for Douglas fir
Authors: Duyzer J. H. , Dorsey J. R. , Gallagher M. W. , Pilegaard K. , Walton S. 
Published: July 2004

AbstractAn existing process‐oriented multi‐layer canopy model is applied to data from an intensive NOx and O3 surface exchange experiment, and a sensitivity study is conducted. The canopy was a mature 22.5 m Douglas fir stand.Comparison of measured data and model results shows that the model represents the concentration and fluxes of ozone well above the canopy, with adequate accuracy for concentration and fluxes below the canopy. A similar pattern is demonstrated for NO2 concentration above and below a forest canopy, with the fluxes being calculated correctly to within at least an order of magnitude below the canopy, and more accurately above. The model can reproduce the processes leading to the observed NO2 emission from forest stands.The sensitivity study demonstrates the complex interdependence of oxidized nitrogen flux controlling variables within the canopy, with NO2 emission favoured by high NO soil emission and canopy resistance and by low global radiation, leaf area index and ambient NO2 concentrations. Realistic alterations of these variables can cause reversal of the NO2 flux, leading to an ‘ecosystem compensation point’ between 17 and 35 ppbv at night, and 5 to 10 ppbv during the day for the forest canopy investigated. This highlights our improved understanding of the controls on NO2 flux, explaining and quantifying some previously reported reversals in NO2 flux above forest canopies.The effect of soil NO emission on ozone flux is investigated. During the day, reaction with NO may account for only 10% of observed ozone deposition, however, at night, this figure can rise to around 50%. The effect of volatile organic compounds on forest ozone deposition was found not to be large. Copyright © 2004 Royal Meteorological Society.
Numerical simulations of the 12–13 August 2002 flooding event in eastern Germany
Authors: Zängl G. 
Published: July 2004

AbstractIn this paper, high‐resolution numerical simulations of the 12–13 August 2002 flooding event in eastern Germany are presented. The simulations are performed with the Penn State/National Center for Atmospheric Research mesoscale model MM5 in a four‐domain configuration with a finest horizontal resolution of 1 km. Sensitivity experiments are performed with coarser resolutions (3 and 9 km), with different cloud microphysical parametrizations and with a different date of initialization. Moreover, tests with 1 km resolution but the smoothed topography of the 9 km runs are conducted in order to isolate the contribution of the model topography to the differences between the 1 km runs and the 9 km runs.The results show that the high‐resolution runs reproduce the observed structure of the precipitation field very well. In particular, the location of the rainfall maximum is correct to within 15 km. The quantitative agreement between model results and observations is fairly good in regions with light to moderate rain, but large amounts of precipitation tend to be underpredicted. For observed 36‐hour rainfall accumulations exceeding 200 mm, the negative bias typically ranges between 15 and 30 Copyright © 2004 Royal Meteorological Society.
Cloud characteristics and channel selection for IASI radiances in meteorologically sensitive areas
Authors: Fourri'e Nadia , Rabier Florence 
Published: July 2004

AbstractThe cloudiness in simulated Infrared Atmospheric Sounding Interferometer (IASI) pixels deduced from the Advanced Very‐High‐Resolution Radiometer (AVHRR) satellite imager is studied specifically in meteorologically sensitive areas during the Fronts and Atlantic Storm‐Track Experiment. It is found that few clear AVHRR observations are located in the IASI pixels in these regions, which are covered by high‐level and low‐level clouds. The IASI channel selection is then studied in the context of the sensitive areas for the pixels with low‐level clouds. The Entropy Reduction (ER) method, which was previously studied in a general context, is compared with two other channel selection methods using selection criteria based on adjoint sensitivity: the sensitivity to observations and the so‐called Kalman‐filter sensitivity. It is found that, even though the ‘sensitive’ methods give slightly better results than the ER one, the latter performs quite robustly and at a lower computational cost. The robustness to the specification of the background‐error covariance matrix is then studied. It is shown that channel selection based on the ER method is particularly robust to the specification of the background‐error covariance matrix, but the analysis step itself requires an accurate determination of the background‐error covariance matrix. In addition it is shown that an independently computed constant channel set gives comparable results to the optimal channel set. Copyright © 2004 Royal Meteorological Society.
1/f noise and pulse‐like events in the tropical atmospheric surface variabilities
Authors: Yano Jun‐ichi , Blender Richard , Zhang Chidong , Fraedrich Klaus 
Published: July 2004

AbstractThis study discusses the 1/f ‐noise behaviour and its connection with pulse‐like events in tropical surface meteorological data. The 1/f noise, withf being frequency, refers to the unique spectrum shape of signals that represents the same degree of variability for a whole spectrum range with very long lag‐correlations. The pulse‐like events are characterized by their high localizations in time and a lack of a distinct spectrum peak.Approximate 1/f ‐noise behaviour is found in tropical surface temperature, moisture, and wind speed for periods of 1 hour to beyond 10 days and in oceanic wind stress up to 2‐year periods. The origin of the 1/f noise can be closely tied to pulse‐like events with a highly intermittent nature in the time series. Examples for such pulse‐like events include the cumulus convection events leading to convective downdraughts and intraseasonal westerly wind events associated with the Madden–Julian oscillations (MJO). A method based on the wavelet is introduced to extract individual pulse‐like events. These events are characterized by a 1/f spectrum extending up to 1–2 decades of frequency centred around their characteristic durations. Their successive occurrences are mutually uncorrelated and the individual pulse‐like events themselves constitute a 1/f spectrum for a frequency range around their durations. The superposition of these events of various durations yields the 1/f ‐noise spectrum for much wider ranges. Physical implications of these findings to convective quasi‐equilibrium and MJO‐El Niño Southern Oscillation relationship are discussed. Copyright © 2004 Royal Meteorological Society.
Benjamin–Feir instability of Rossby waves on a jet
Authors: Esler J. G. 
Published: July 2004

AbstractLarge‐scale waves on the extratropical tropopause have been widely observed to spontaneously organize into groups or wave packets. Here, a simple paradigm for this wave packet formation is presented. Firstly, a weakly nonlinear theory of Rossby wave propagation on a potential‐vorticity front, based on small non‐dimensional wave amplitude ε, is developed. As is typical for systems allowing conservative one‐dimensional wave propagation, the evolution of the wave envelope is governed by the nonlinear Schrödinger equation. The sense of the nonlinearity is consistent with Benjamin–Feir instability, where uniform wave trains are unstable to sideband modulations, leading to the formation of wave packets. Next, numerical results from contour dynamics integrations show that the weakly nonlinear predictions for sideband growth rates are quantitatively accurate up to ε∼0.5, and that unstable sideband growth is qualitatively similar, but slower than predicted, at higher values of ε. For ε≥0.6 the formation of wave packets leads to wave‐breaking, this occuring at much lower initial wave amplitudes than for unmodulated uniform wave trains previously studied. The numerical results reveal that the length and time‐scales of the Benjamin–Feir instability are broadly consistent with observed wave packet formation in the extratropics. Copyright © 2004 Royal Meteorological Society.
Ability of Electric Field Strength, Frequency, and Current Duration to Stun Farmed Atlantic Salmon and Pollock and Relations to Observed Injuries Using Sinusoidal and Square Wave Alternating Current
Authors: Roth Bjorn , Moeller Dag , Slinde Erik 
Published: July 2004

Abstract
The effects of electricity as a stunning method in the slaughtering process of Atlantic salmon Salmo salar and pollock Pollachius virens were studied. About 330 slaughter-sized Atlantic salmon were exposed to sinusoidal alternating current (AC) in seawater. Electrical field strength ranged from 25 to 100 V/m and current duration from 1 to 10 s at frequencies between 30 and 2,000 Hz. In addition, 122 pollock and 25 salmon were stunned by applying square wave AC in the range of 50–1,000 Hz. After stunning, subsequent unconsciousness was evaluated by means of behavioral responses, and injuries were observed by examining fillets. For sinusoidal AC, the proportion of Atlantic salmon sufficiently stunned and the occurrences of obviously broken spinal columns and hemorrhages were dependent on the electrical frequency used. The AC frequency was the most predominant factor in both stunning and inflicted injuries. The proportion of injured salmon exhibited a unimodal response to sinusoidal AC frequency, increasing from 30 Hz to 50– 80 Hz and declining with higher frequencies. There was not a consistent injury-versus-frequency pattern for pollock exposed to square wave AC. For Atlantic salmon, use of square wave AC did inflict a higher rate of injuries than that of sinusoidal AC. For minimizing the occurrence of injuries while sustaining sufficient stunning before slaughter, sinusoidal AC frequencies between 500 and 1,000 Hz are recommended at field strengths exceeding 50 V/m and current durations of 10 s.
Effects of Clove Oil, Tricaine, and CO2 on Gamete Quality in Steelhead and White Sturgeon
Authors: Holcomb M , Woolsey J , Cloud J G , Ingermann R L 
Published: July 2004

Abstract
This study examined the direct impact of three commonly used anesthetics—clove oil (86% eugenol), tricaine (tricaine methanesulfonate [MS-222]), and CO2—on egg quality for steelhead Oncorhynchus mykiss and that of clove oil and tricaine on the motility of sperm from both steelhead and white sturgeon Acipenser transmontanus. Exposure of unfertilized eggs for 6 or 24 h to 150 mg clove oil/L, 225 mg tricaine/L, or less than 100 mm Hg CO2 resulted in no reduction in egg fertility or embryo survival to hatch. However, higher doses (1,500 mg clove oil/L; 2,250 and 22,500 mg tricaine/L; or more than 125 mm Hg CO2) negatively impacted egg quality. Similarly, a 3-h exposure to clove oil (150 mg/L) or tricaine (225 mg/L) produced no significant effect on sperm motility in steelhead. White sturgeon sperm showed a modest decline in motility after incubation in clove oil. Thus, the data suggest that clove oil and tricaine can be used on fish prior to gamete harvesting without significant adverse impacts on gametes. Although CO2 is unlikely to have deleterious effects on eggs, CO2-associated declines in ovarian fluid pH may be of concern when ovarian fluid pH is used as an indicator of egg quality.
Comparison of Production, Meat Yield, and Meat Quality Traits of NWAC103 Line Channel Catfish, Norris Line Channel Catfish, and Female Channel Catfish × Male Blue Catfish F1 Hybrids
Authors: Bosworth Brian G , Wolters William R , Silva Juan L , Chamul Roberto S , Park Sinyoung 
Published: July 2004

Abstract
NWAC103 line channel catfish Ictalurus punctatus, Norris line channel catfish, and Norris line female channel catfish × Dycus Farm line male blue catfish I. furcatus F1 hybrids were compared for production, meat yield, and meat quality traits. Juvenile fish from each genetic group were stocked at 12,000 fish/ha into three, 0.04-ha ponds per genetic group. Fish were fed once daily to satiation from June through October, and fed on days when afternoon water temperatures were above 17°C from November through December. Fish were harvested, weighed, and counted in January, and 150 fish per genetic group (50 fish per pond) were processed and measured for meat and body component yield. Instrumental and sensory panel evaluations of quality were measured on fresh, frozen-thawed, and baked fillets. Stocking weight, harvest weight, and net production (kg/ha) were highest for the NWAC103 line channel catfish, intermediate for the hybrid, and lowest for the Norris line channel catfish. Growth at unit size (a), percent weight gain, survival, and feed conversion were not significantly different among genetic groups. Carcass yield (relative to whole weight) and fillet yield were higher for the hybrid than for the two channel catfish lines, and higher for females than for males in all genetic groups. Head yield and total viscera yield were higher for the channel catfish lines than the hybrid. Head yield was higher for males than for females, and total viscera yield was higher for females than for males. Visceral fat yield was higher for the hybrid than for the two channel catfish lines. Instrumental and sensory panel analysis indicated only minor differences among genetic groups for fillet quality. Thus, catfish producers and processors can improve important traits and increase profits by utilizing catfish lines with superior performance.
Application of Chemical Coagulation Aids for the Removal of Suspended Solids (TSS) and Phosphorus from the Microscreen Effluent Discharge of an Intensive Recirculating Aquaculture System
Authors: Ebeling James M , Ogden Sarah R , Sibrell Philip L , Rishel Kata L 
Published: July 2004

Abstract
An evaluation of two commonly used coagulation–flocculation aids (alum and ferric chloride) was conducted to determine optimum conditions for treating the backwash effluent from microscreen filters in an intensive recirculating aquaculture system. Tests were carried out to evaluate the dosages and conditions (mixing and flocculation stirring speeds, durations, and settling times) required to achieve optimum waste capture. The orthophosphate removal efficiency for alum and ferric chloride were greater than 90% at a dosage of 60 mg/L. Optimum turbidity removal was achieved with a 60-mg/L dosage for both alum and ferric chloride. Both alum and ferric chloride demonstrated excellent removal of suspended solids from initial total suspended solid values of approximately 320 mg/L to approximately 10 mg/L at a dosage of 60 mg/L. Flocculation and mixing speed and duration played only a minor role in the removal efficiencies for both orthophosphates and suspended solids. Both coagulation–flocculation aids also exhibited excellent settling characteristics, with the majority of the floc quickly settling out in the first 5 min.
Changes in Water Hardness Influence Colonization of Saprolegnia diclina
Authors: Barnes Michael E , Gabel Audrey C , Durben Dan J , Hightower Timothy R , Berger Tate J 
Published: July 2004

Abstract
Experiments were conducted to determine the effects of different water hardness concentrations on colonization of Saprolegnia diclina in an attempt to explain some of the differences in fungal growth and antifungal chemical effectiveness observed at various fish hatcheries. Fungal growth on nonviable seeds of hemp Cannabis sativa was observed significantly sooner in water where hardness was elevated due to the addition of calcium sulfate dihydrate in each of the experiments. Seeds in test tubes containing water with a hardness of 300 mg/L exhibited fungal colonization in approximately one-half the amount of time observed with seeds in water with hardness less than 150 mg/L. In petri dishes containing inoculated corn meal plugs, the growth of S. diclina was observed at only 24 h on seeds in water with a hardness of 450 mg/L, which was significantly quicker than the 31 h from seeds in water hardness of 150 and 300 mg/L. This, in turn, was significantly quicker than the 35 h required for growth in the 0 mg/L hardness control water. Results were similar in a subsequent experiment where the inoculated plugs were removed from the petri dishes prior to seed placement. The relatively minor changes in pH following the addition of water hardness-altering chemicals did not affect the timing of fungal colonization, as a separate experiment indicated no differences in fungal growth in pH ranging from 3 to 10.
Demonstrating Data and Test Result Validity for Diagnostic Aquatic Animal Health Laboratories
Authors: Wiegers Ann L. , Heidel Jerry R. , Scarfe A. David 
Published: July 2004

Abstract
The information in this article is aimed towards the managers in laboratories that conduct testing in support of aquatic animal disease diagnosis or the determination of health status. This includes laboratories that do regulatory work—directly or indirectly—those who do testing for trade, and those who will be required to respond swiftly and effectively in the case of a national animal health emergency. The ability to demonstrate validity is essential for national security, protection of public and animal health, minimization of liability, and support of business and trade. Veterinarians, wildlife specialists, and aquatic animal health specialists may also find it valuable, as many points are directly pertinent to the establishment of a quality program in a clinical or individual practice laboratory. Data and test result validity are critical to timely and accurate diagnosis and treatment, effective disease and health management, reliable surveillance, and quick, appropriate responses in the event of an animal health emergency. There are currently four general areas of importance regarding the demonstration of data and test result validity: The conduct of testing; the use of valid, approved test methods; proficiency testing; and the use of reference materials. Demonstration of validity is achieved via the implementation and use of appropriate and documented technical, operational, and managerial policies, systems, procedures, and specifications that are scientifically sound, that meet the requirements of relevant third-party consensus standards, and that can be verified by recognized, third-party accreditation. The basis for the requirements of laboratory accreditation and accreditation body recognition programs in the United States and internationally that address these areas of analytical endeavor is discussed. Recent legislation and activities in establishing a unified national system of accreditation that meets applicable international standards may assist in creating national laboratory systems capable of effectively addressing data and test result validity and credibility in critical diagnostic areas.