bluuebunny/crossref_metadata_2025 huggingface dataset:
Surface chloride salt formation on space shuttle exhaust alumina
Authors: Cofer W. R. , Pellett G. L. , Sebacher D. I. , Wakelyn N. T.
Published: February 2008

Aluminum oxide samples from the exhaust of space shuttle launches STS‐1, STS‐4, STS‐5, and STS‐6 were collected from surfaces on or around the launch pad complex and chemically analyzed. The water‐soluble fraction, pH, acid‐soluble fraction, and insoluble fraction were determined for each sample. X ray diffraction analysis of the insoluble particulate fractions (always >72% of the sample weight) indicated that these fractions were α‐Al2O3 and thus confirmed that the six samples analyzed were space shuttle alumina. Electron microscopic examination of the particles revealed spherical morphologies with diameters ranging from about 1 to 25 μm. Calcium, magnesium, potassium, ammonium, and sodium ions were measured as indicators of the amount of ground debris or sea‐salt particles incorporated into the samples. All samples analyzed contained significantly elevated amounts of water‐soluble chloride and aluminum (III) ion. Results from these analyses, and from laboratory experiments in which calcination‐produced aluminas were exposed to gaseous HCl and H2O mixtures from room temperature to 220°C, suggest that the surface of the shuttle exhaust alumina particulates should be viewed as having more of the characteristics and properties (e.g., hydrophilicity) of aluminum chlorides and oxychlorides than of aluminum oxides. Since our collection techniques were crude and strongly biased toward the collection of large particles, similar surface analyses of particles collected from high‐altitude shuttle exhaust plumes are needed.
Deep 0°C isothermal layers within precipitation bands over southern Ontario
Authors: Stewart Ronald E.
Published: February 2008

Isothermal layers having a temperature of 0°C and depths up to 1 km were measured within two precipitation bands occurring within autumn storms over southern Ontario. Across these layers, wind shears up to 0.02 s−1 existed, and aggregation led to particles up to ∼20 mm in diameter. Melting and evaporation are proposed as contributing to the development of the layers.
A variational formulation for time‐dependent climate models
Authors: Smith G. Louis
Published: February 2008

A variational principle for time dependent diffusion problems is presented and is demonstrated by applying it to simple seasonal climate models. Two cases are treated. The first, a North‐Coakley‐type model with constant properties, is used as a tutorial example for the application of the technique. For the second case, heat capacity and thermal conductivity are considered to be latitude dependent in order to treat the effects of land/ocean distribution on the seasonal temperature distribution over the earth. The variational equations are derived and approximate analytical solutions are developed which delineate the influences of the physical asymmetries of the hemispheres in producing an asymmetric annual cycle.
Records of atmospherics aT 30 kHz during a tropical cyclone
Authors: Bhattacharya R. , Bhattacharya A. B.
Published: February 2008

Some characteristics in the atmospherics record at Calcutta during a violent cyclonic storm over the Indian Ocean and the Bay of Bengal have been noted. The results are presented here.
Highly soluble atmospheric trace gases in the southwestern United States: 1. Inorganic species: NH3, HNO3, SO2
Authors: Dawson G. A. , Farmer J. Carl
Published: February 2008

Atmospheric concentrations of NH3, HNO3, and SO2 have been measured at a variety of sites in the southwestern United States over the last few years. Sampling was by condensation collection. Over much of the region, NH3 is associated primarily with agricultural activity, HNO3 mostly with urban emissions, and SO2 with industrial effluent. However, relatively high SO2 concentrations (1 ppb) were observed at a remote coastal site, indicating substantial natural release of sulfur compounds in this area. Data from a relatively remote site in southern Arizona showed that copper smelting in the region increased SO2 levels from 0.3 to 2 ppb and probably caused a small increase in HNO3 levels. There were large diurnal variations of both components, though perhaps with different causes. Urban concentrations of SO2 and HNO3 were unaffected by smelting. Levels of NH3 varied with proximity to agricultural sources. Average values of 10 ppb were observed close to a recently fertilized field. The most frequent concentration observed at the more remote sites (taken to be background for the area) was 0.9 ppb NH3. Diurnal and seasonal variations of NH3 were small.
Pressure wave generated by the Mount St. Helens eruption
Authors: Banister John R.
Published: February 2008

Histories of the air pressure wave radiated from the eruption of Mount St. Helens on May 18, 1980, were calculated for two models of the eruption cloud expansion. The first considered the wave radiated from an accelerated plane surface, while the second examined the wave radiated from an expanding hemisphere. Two histories of eruption cloud motion based on photographs were used. Peak positive overpressures were about the same for these cloud motion histories of expansion into a hemisphere was assumed. If an accelerated planar source model was used, the peak positive pressures have again about the same value in east and west direction, but values are about half in the north and south direction. Observed peak overpressures at microbarograph stations are somewhat higher than the calculated with the most marked departures at the greater surface ranges. These observed overpressures may have been about half the correct values, however. Microbarograph records show a weaker rarefaction than calculated histories or none at all. This can be explained, in part, by a lack of areal motion coherence in the slowing eruption cloud. It is also possible the net ash cloud volume increased considerably after its vertical growth ceased and weakened the negative phase as well as lengthening the positive phase.
A calibration adjustment technique combining ERB parameters from different remote sensing platforms into a long‐term data set
Authors: Ardanuy Philip E. , Jacobowitz Herbert
Published: February 2008

Earth Radiation Budget (ERB) experiments on board the NIMBUS 6 (ERB 6) and NIMBUS 7 (ERB 7) spacecraft have measured wide‐field‐of‐view (WFOV) total (0.2 to 50 μm), shortwave (0.2 to 3.8 μm), and near‐infrared (0.7 to 2.8 μm) terrestrial irradiances for a joint lifetime of over 8 years. Though the spectral characteristics of both experiments are nearly identical, instrument degradation and altitude differences introduce discrepancies between the two data sets. ERB parameters from these two observing platforms may be combined into a scientifically meaningful data set only after these discrepancies are eliminated. To facilitate the creation of a long‐term ERB data set, comparisons of the ERB 6 experiment irradiances with, and calibrations adjustments with respect to, the corresponding ERB 7 irradiances have been performed. Two calibration methods were developed and applied to the irradiance data from 28 pairs of collocated orbits. The differential effects of altitude, illumination, albedo, and scene inhomogeneities were applied. The result is a set of calibration adjustments that adjust the ERB 6 data to match the ERB 7 data.
Degradation asymmetries and recovery of the NIMBUS 7 Earth Radiation Budget Shortwave Radiometer
Authors: Ardanuy Philip , Rea Jim
Published: February 2008

Shortwave reflected terrestrial irradiance is routinely measured at satellite altitude by wide field‐of‐view radiometers on board earth radiation budget experiments. Although these irradiances are then corrected for time‐dependent variations in mean filter‐dome transmissivity, asymmetries in the amount of degradation over the filter dome hemisphere have the potential of producing large biases in the estimated irradiance field when positively or negatively correlated with inhomogeneities in the incident radiance field. The extent of this asymmetry, caused by the combination of instrument configuration and contamination, direct and diffuse solar radiation and contact with exospheric constituents, is obtained empirically for the radiometer on board the NIMBUS 7 spacecraft during the first data year. Further analysis assesses the impact of this phenomenon on earth radiation budget parameter measurements.
Temperature comparisons between the NIMBUS 7 SAMS, rocket/radiosondes and the NOAA 6 SSU
Authors: Barnett J. J. , Corney M.
Published: February 2008

The stratospheric and mesospheric sounder (SAMS) on the NIMBUS 7 satellite is a limb sounder measuring infrared thermal emission from gases in the earth's atmosphere. Carbon dioxide measurements near 15 μm are used to determine the temperature profile and satellite roll angle. These temperature fields are compared with measurements by the NOAA 6 SSU and radio/rocketsondes over a 13‐month period in 1980/81. Consistent patterns of bias between the instruments are found but are generally less than 2 K. Some of these are attributed to atmospheric tides, but others appear to indicate errors, including a problem caused by atmospheric ozone affecting lower‐stratosphere SAMS measurements. Remarkably good agreement is found between variations measured by the three sensors, with standard deviations of difference typically of 1 K and correlation coefficients of up to 0.994 over the whole period.
Evaluation of NIMBUS 7 THIR/CLE and Air Force three‐dimensional nephanalysis estimates of cloud amount
Authors: Stowe Larry L.
Published: February 2008

Three different estimates of the percent of fixed geographical regions (160×160 km) either free of cloud (clear) or covered by low, middle, and high (opaque) cloud have been intercompared. The estimates were derived by analysts interpreting geosynchronous satellite images, with concurrent meteorological observations; from NIMBUS 7 temperature humidity infrared radiometer (THIR) CLOUDS ERB (CLE) data; and from Air Force three‐dimensional (3‐D) nephanalysis (3DN) data. Standard linear regression and correlation statistics have been used to estimate the systematic and random errors of the CLE and 3DN cloud amounts (independent variable) at different altitudes relative to the analyst (dependent variable). It has been concluded that (1) Air Force 3‐D nephanalysis agrees better with the analyst than THIR/CLE, except for high cloud amount; (2) the CLE and 3DN results show the tendency to overestimate clear amount when clear amount is large and underestimate it when clear amount is small, by 10–20% for CLE and by 5–10% for 3DN, and both agree well with the analyst in the mean; (3) 3DN and CLE systematic errors relative to the analyst are largest for low cloud, typically underestimating the amount by 15%; (4) both 3DN and CLE random errors range between 6 and 30%, smallest for high clouds and greatest for low clouds; (5) CLE estimates of cloud amount over land at night should not be used for scientific investigations unless restricted to high cloud amount.
Radiative relaxation rates for individual 15‐μ CO2 lines in the upper stratosphere and lower mesosphere
Authors: Apruzese John P. , Strobel Darrell F.
Published: February 2008

Using an exact multifrequency algorithm, relaxation rates for individual 15‐μ CO2 lines have been calculated in the upper stratosphere and lower mesosphere for the Cira (1972) global mean reference atmosphere. The relaxation rate dependence on wave number is obtained and examined as a function of line strength and altitude, to clarify the underlying physics. Wave numbers n≲2.09 km−1 are accurately treated by the algorithm. The most rapid growth of relaxation rate with wave number is τ−1∝ n1.2, which occurs for strong, mostly Doppler‐broadened lines in the mesosphere. Overall relaxation rates for the CO2 15‐μ band complex are obtained from an approximate model of the line strength distribution; these rates corroborate previous results of Fels. Our results for individual lines, however, differ significantly from Fels' parameterization. Comparison of the present results with our previous rates obtained with the diffusion approximation demonstrates reasonably good agreement down to wavelengths of ∼8 km, below which this approximation seriously overestimates the relaxation rate.
The impact of Seasat scatterometer winds on the Navy's Operational Model
Authors: Duffy D. , Atlas R. , Rosmond T. , Barker E. , Rosenberg R.
Published: February 2008

The question of whether Seasat scatterometer wind data can have a positive impact on an operational numerical weather prediction (NWP) model is examined. Comparisons are made between assimilations and forecasts made with the Navy's operational forecast and analysis system (NOGAPS) when Seasat data are included or excluded. S1 scores and rms differences show that Seasat data had a negligible effect on NWP forecasts made from the Navy's model in both the northern and the southern hemisphere. A global subjective analysis of all of the forecasts shows similar results.
Trends of atmospheric CO2 over Canadian WMO background stations at Ocean Weather Station P, Sable Island, and Alert
Authors: Wong C. S. , Chan Y.‐H. , Page J. S. , Bellegay R. D. , Pettit K. G.
Published: February 2008

Time series data of atmospheric CO2 concentrations are presented for three Canadian background stations: Ocean Weather Station P in the northeast Pacific Ocean, Sable Island off Nova Scotia, and Alert, Northwest Territories. The mean annual concentrations of CO2 in dried samples of 338.73 parts per million by volume (ppmv) (1980) at Sable Island, 337.26 ppmv (1980) at Station P, and 340.30 ppmv (1980) and 341.71 ppmv (1981) at Alert appear consistent with the global pattern. From 1975 to 1981, the increase in CO2 concentration averaged for these stations is 1.4 ppmv/yr. In 1975–1976 and in 1978, the annual growth rates of atmospheric CO2 measurements decreased at all stations. Another dip in the growth rate of CO2 concentrations was also observed in 1974–1975 at Station P. In general, the long‐term trends all show lower growth in the beginning, and more rapid growth at the end, of a typical 2‐year El Niño/Southern Oscillation event. The seasonal amplitude between winter and summer concentrations is about 14 ppmv at Station P and about 15 ppmv at the other stations. There is a phase shift of about 1 month in the onset of the decline to summer minimum between Sable Island (March–April) and the other stations (April–May).
Measurements of free tropospheric ozone: An aircraft survey from 44° north to 46° south latitude
Authors: Gregory Gerald L. , Beck Sherwin M. , Williams Jerry A.
Published: February 2008

Ozone data were obtained in the free troposphere at altitudes of 5 to 7.5 km and at latitudes from 44°N to 46°S during a 3‐week period from October 19 to November 4, 1982. Flight trajectories included the continental U.S., Central America, and the western coast of South America. Maximum observed ozone was 110 ppb at about 41°S latitude and at an altitude of 7.3 km (msl). Analysis of the data as a function of latitude showed a region of elevated ozone in the southern latitudes extending from about 2° to 30° in which latitudinal ozone averages (2° bands) peaked at about 80 ppb. Ozone concentrations, measured at northern latitudes, were lower, averaging about 35 ppb. A discussion of the data, including comparison with other ozone data sets, is presented.
Atmospheric electric modulation during a sea breeze
Authors: Trevitt A. Chris
Published: February 2008

An increase of more than 40% in both the mean and fluctuating parts of the electric field strength and air‐earth current has been observed during the day‐time development of the convective boundary layer under the influence of the sea breeze. This is attributed to the advection and turbulent organization of surf‐ and wave‐generated space‐charge. Fluctuations in the electric field strength have been subjected to variance spectral analysis in the range 0.001<f<0.05 Hz. Spectral estimates are found to be proportional to fx where x = −1.62 ± 0.19. This is compared with the −5/3 value applicable to the wind vectors, temperature, and humidity in the surface layer. An attenuation of short‐period, horizontal charge‐cloud structures is observed with the influx of sea air.
An intercomparison of carbon monoxide, nitric oxide, and hydroxyl measurement techniques: Overview of results
Authors: Hoell J. M. , Gregory G. L. , Carroll M. A. , McFarland M. , Ridley B. A. , Davis D. D. , Bradshaw J. , Rodgers M. O. , Torres A. L. , Sachse G. W. , Hill G. F. , Condon E. P. , Rasmussen R. A. , Campbell M. C. , Farmer J. C. , Sheppard J. C. , Wang C. C. , Davis L. I.
Published: February 2008

Results from an intercomparison of methods to measure carbon monoxide (CO), nitric oxide (NO), and the hydroxyl radical (OH) are discussed. The intercomparison was conducted at Wallops Island, Virginia, in July 1983 and included a laser differential absorption and three grab sample/gas Chromatograph methods for CO, a laser‐induced fluorescence (LIF) and two chemiluminescence methods for NO, and two LIF methods and a radiocarbon tracer method for OH. The intercomparison was conducted as a field measurement program involving ambient measurements of CO (150–300 ppbv) and NO (10–180 pptv) from a common manifold with controlled injection of CO in incremental steps from 20 to 500 ppbv and NO in steps from 10 to 220 pptv. Only ambient measurements of OH were made. The agreement between the techniques was on the order of 14% for CO and 17% for NO. Hardware difficulties during the OH tests resulted in a data base with insufficient data and uncertainties too large to permit a meaningful intercomparison.
The dry deposition of nitric acid to grass
Authors: Huebert B. J. , Robert C. H.
Published: February 2008

We measured the dry flux of nitric acid vapor to a pasture near Champaign, Illinois during June of 1982. The mass flux was determined by a modified Bowen‐ratio method, employing the surface sensible heat flux and temperature and concentration variations with altitude. We found the daytime average deposition velocity to be 2.5±0.9 cm/s. The average canopy (stomatal and adsorption) resistance averaged virtually zero. The measured June dry flux of HNO3 was of the same magnitude as the wet flux measured nearby.
Cumulus convection and climatic temperature perturbations
Authors: Ou Szu‐cheng S. , Liou Kuo‐Nan
Published: February 2008

The influence of cumulus convection on the equilibrium temperature perturbations due to the doubling of CO2 is investigated by using a one‐dimensional radiative‐turbulent model. The model includes parameterizations of solar and infrared radiative flux transfer in clear and cloudy conditions, vertical eddy sensible and latent heat fluxes, surface albedo feedback, and an interactive cumulus convection. The cumulus parameterization employed is basically a Kuo‐type scheme described and modified by Anthes. In addition the criteria for cumulus convection to take place is derived from values associated with the surface relative humidity and the vertical profile of moist static energy. In the numerical experiments it is found that the extent of condensational heating due to cumulus convection is determined by the depth of the conditionally unstable layer and the total amount of buoyancy force generated by the excess cloud temperature over the surrounding temperature. With the incorporation of cumulus convection, an atmosphere with a high relative humidity will generate a higher temperature near the surface. Also, a higher surface relative humidity will generate a larger upward shift in equilibrium condensational heating rates. Perturbation experiments reveal that the sensitivity of cumulus convection to the surface temperature increase due to doubling of CO2 is not apparent under mean annual global conditions with a realistic surface relative humidity of 85%. However, with the incorporation of cumulus convection and fixing the horizontal transport of sensible and latent heat fluxes, it is shown that the surface temperature increase in a tropical atmosphere due to doubling of CO2 significantly reduces from 4.3 to 2.5°K with the upward shift of temperature increases especially evident in upper tropospheric levels. Finally, it is also noted that the tropospheric temperature profile in the tropics generated by the present one‐dimensional model with cumulus convection agrees closely with that provided by Oort and Rasmusson for mean annual climatological conditions.
Delayed production of sulfuric acid condensation nuclei in the polar stratosphere from El Chichon volcanic vapors
Authors: Hofmann D. J. , Rosen J. M. , Gringel W.
Published: February 2008

Using balloon‐borne condensation nuclei counters at Laramie, Wyoming (41°N), a large increase in what appear to be small sulfuric acid droplets above 29‐km altitude was detected on January 28, 1983. Simultaneous reductions in electrical conductivity in the layer supported the aerosol observations. The air sample associated with this event appears to have originated in the north polar region where a stratospheric warming episode was taking place. It is believed that the substantial warming in the region may have been sufficient to vaporize resident sulfuric acid aerosol which were mainly derived from the El Chichon volcanic eruption 10 months earlier and transported to the polar region during winter. It is further believed that subsequent rapid cooling of the vapor during transport to the latitude of Laramie resulted in the nucleation of the small droplets, forming an extensive sulfuric acid fog above 29 km. The upper boundary of the cloud was not determined but extended to at least the maximum altitude attained (32.5 km). Longitudinal spreading appears to have been rapid, and remnants of the fog were detected as far south as 32°N in May and persisted throughout the year at Laramie. A similar phenomenon is believed to occur in the Antarctic stratosphere as revealed in a measurement there in the southern hemisphere spring (October 1983).
Analysis of the “Spinup” of a general circulation model
Authors: Simmonds Ian
Published: February 2008

In this paper we examine in detail the “spinup” of a general circulation model of the atmosphere, initialized with isothermal, dry, calm conditions with a constant surface pressure. The speed at which the spinup occurs depends on the atmospheric parameter and geographical location being examined. What is made clear here are the different thermodynamic and dynamic time scales associated with the problem, these ranging from a few to hundreds of days. A simple analysis suggests the spinup of the atmosphere may not be too different from the atmospheric response to a small perturbation, particularly in tropical regions. The times required for a simple model to readjust to “small” changes can be of the order of 6 months or more, in agreement with observational studies. Such long atmospheric time scales may be of considerable importance in explaining interannual variability.
Tropospheric aerosol perturbations due to volcanism as measured by electrical conductivity of ocean air
Authors: Meyerott R. E. , Reagan J. B. , Evans J. E.
Published: February 2008

Electrical conductivity measurements of ocean air have been made since 1907, and since the electrical conductivity depends on the aerosol concentration in the air, these measurements constitute the longest running record of the aerosol concentration of marine air. The conductivity measurements in the northern hemisphere show an apparent decrease with time, while those in the southern hemisphere are reasonably constant. The apparent increase in aerosol concentration with time in the northern hemisphere, implied by the decrease in conductivity, has been taken by earlier authors to be caused by pollution from the increased industrial development in the northern hemisphere. Ellsaesser (1975), however, pointed out that this interpretation is not consistent with other indications of pollution trends. In this paper an examination is made of the possibility that the apparent increase in aerosol concentration in the northern hemisphere may be due to the increase in the number of moderate‐sized volcanic eruptions in the northern hemisphere that have been reported during the past half century. In this paper the historical record of volcanic activity and conductivity measurements is examined. It is found that decreases in conductivity and the corresponding increases in aerosol concentration appear to occur within a few months following moderately large volcanic eruptions. The more numerous moderate‐sized eruptions appear to have a greater effect than the relatively few very large eruptions. The good correlation between known volcanic eruptions and the decreases in conductivity suggests that the decreases in fair‐weather marine conductivity during this century is indicative of an increase in volcanic activity. Thus the suggestion of Newhall and Self (1982) that the increases in volcanic activity may be only apparent because of better reporting is not fully conclusive. While it is true that the reporting has improved over the past 70 years, our results support the assumption that there has also been a de facto increase in such volcanic activity.
Heavy ionospheric ions in the formation process of noctilucent clouds
Authors: Björn L. G. , Kopp E. , Herrmann U. , Eberhardt P. , Dickinson P. H. G. , Mackinnon D. J. , Arnold F. , Witt G. , Lundin A. , Jenkins D. B.
Published: February 2008

Results from a multinational rocket experiment in noctilucent cloud (NLC) conditions are presented. Weak NLC was detected at 83 km by visible photometry. Two separate ion mass spectrometer experiments both detected a narrow layer of very heavy positive ions at 90 km. The mass distribution of the large ions showed an increase of “most abundant mass” with height up to 90 km, indicating a temperature decrease up to that altitude. At 90 km the ion size approached the critical size at which nucleation of ice particles can start. If water ice particles would be formed in such a layer, they would continue to grow, as long as the ambient temperature is low enough and the water supply sufficient. While sedimenting through the atmosphere, they would add to the existing population of aerosol particles and thereby increase the total surface area of particles. Such an increased surface area of small particles would increase the loss rate for electrons and cause a deficiency of electrons at heights below the nucleation layer. A pronounced deficiency of electrons below 90 km was found in the measurements. With a theoretically modeled mesospheric H2O concentration, ice particle growth at 90 km is impossible. This situation may, however, change completely under the influence of an upwelling in the mesosphere. In addition to lowering the sink rate of the particles, such an upwelling would increase the concentration of H2O by vertical transport, and lower the gas temperature, which would also enhance the probability of particle growth. The upwelling would have to terminate in a horizontal motion above 90 km. At this height the rocket measurements show marked changes in the atomic oxygen concentration, electron/positive ion ratio and inferred concentrations of nitric oxide and negatively charged aerosol particles in addition to abrupt changes in positive ion composition.
A ray tracing model of gravity wave propagation and breakdown in the middle atmosphere
Authors: Schoeberl Mark R.
Published: February 2008

Gravity wave ray tracing and wave packet theory is used to parameterize wave breaking in the mesosphere. Rays are tracked by solving the group velocity equations, and the interaction with the basic state is determined by considering the evolution of the packet wave action density. The ray tracing approach has a number of advantages over the steady state parameterization of Lindzen (1981), as the effects of gravity wave focusing and refraction, local dissipation, and wave response to rapid changes in the mean flow are more realistically considered; however, if steady state conditions prevail, the method gives identical results to Lindzen (1981). The ray tracing algorithm is tested by using both interactive and noninteractive models of the basic state. In the interactive model, gravity wave interaction with the polar night jet on a β plane is considered. The algorithm produces realistic polar night jet closure for weak topographic forcing of gravity waves. Planetary‐scale waves forced by local transfer of wave action into the basic flow in turn transfer their wave action into the zonal mean flow. Highly refracted rays are also found not to contribute greatly to the climatology of the mesosphere, as their wave action is severely reduced by dissipation during their lateral travel.
A possible relationship between tropical ocean temperatures and the observed amplitude of the atmospheric (1, 1) Rossby normal mode
Authors: Hamilton Kevin
Published: February 2008

Space‐time spectral analysis was applied to 17 years of twice daily, northern hemisphere sea‐level pressure grids. The results for each individual year were compared with values of the sea surface temperature averaged over a large region in the tropical Eastern Pacific Ocean. This comparison revealed a positive correlation between the ocean temperature and the pressure variance at the zonal scales and frequencies generally associated with the gravest, westward propagating, zonal wave number 1, symmetric normal‐mode Rossby wave (i.e., the (1, 1) mode). Variations in the surface temperature in the tropical Pacific are known to be accompanied by large changes in the distribution of tropical precipitation; thus the present results suggest that latent heat release may be a major excitation mechanism for the (1, 1) Rossby normal mode.
Chloride and sodium content in northeastern United States precipitation
Authors: Lebowitz L. G. , de Pena R. G.
Published: February 2008

The analysis of 4 years (1978–1981) of precipitation chemistry data collected by the MAP3S program shows that coastal sites have high concentrations of Cl− and Na+ and a ratio Cl−/Na+ that approximates the seawater value with no significant “excess” of any of these ions. At inland stations the concentrations are lower, and the ratio Cl−/Na+ is higher than the seawater value with an “excess” of Cl−, which is statistically significant. No significant trend among the inland stations was observed for the Cl− and Na+ concentrations or their ratio.
Solar absolute spectral irradiance 118–300 nm: July 25, 1983
Authors: Mount George H. , Rottman Gary J.
Published: February 2008

The full‐disk solar absolute spectral irradiance in the spectral range 118–300 nm was obtained from a rocket observation above White Sands Missile Range, New Mexico, on July 25, 1983, halfway in time between solar maximum and solar minimum. Comparison with measurements made in May 1982 shows no changes within the absolute errors of the experiment. Comparison with measurements made during solar maximum in 1979 and 1980 indicates a large decrease in the absolute solar irradiance at wavelengths below 190 nm. The absolute calibration of the instruments for this flight was accomplished at the National Bureau of Standards Synchrotron Radiation Facility.
The vertical distribution of CFC‐114 (CClF2‐CClF2) in the atmosphere
Authors: Fabian P. , Borchers R. , Krüger B. C. , Lal S.
Published: February 2008

Vertical profiles of CFC‐114 obtained by gas chromatographic analyses of stratospheric air samples collected during three balloon flights at Aire sur l'Adour, France (44°N) are presented. Neon‐cooled cryogenic samplers of Max‐Planck‐Institut für Aeronomie were launched on September 20, 1982, September 10, 1983, and October 1, 1984. The average 1982–1984 midlatitude profile of CFC‐114 obtained by averaging the results of these flights shows mixing ratios decreasing from 10.5 pptv at 10 km to 2.7 pptv at 35 km. Results obtained with a time‐dependent 1‐D model based on CFC‐114 global emission rates evaluated by Wuebbles (1983) are in good agreement with our measured distribution when Wuebbles' data are scaled by a factor 1.16. The distribution calculated for steady state conditions shows a slower falloff with height in the stratosphere.
Measurement of the turbulent fluxes of ions to the Earth's surface at the Amundsen‐Scott South Pole Station
Authors: Henry Robert F.
Published: February 2008

During November and December of 1981, surface‐layer eddy fluxes of small atmospheric ions were measured at the Amundsen‐Scott South Pole Station. This was done in the electrode layer at a height of 2.5 m by means of the eddy correlation method. The mean eddy fluxes of positive and negative ions were found to be approximately 40 and 440 cm−2 s−1 respectively, and the fluxes were always found to be toward the ground. The large difference between the two is attributed to the electrode effect, which is responsible for a large gradient in the negative ion concentration.
Two‐dimensional monthly average ozone balance from limb infrared monitor of the stratosphere and stratospheric and mesospheric sounder data
Authors: Jackman Charles H. , Stolarski Richard S. , Kaye Jack A.
Published: February 2008

Stratospheric constituents are determined by continuity equations including photochemical production and loss as well as the transport and diffusion terms and explicit time variation. Photochemical models self‐consistently solve these equations to determine species concentrations. Recent Nimbus 7 measurements give us a first chance to analyze diagnostically the global atmosphere for consistency. We compute the diurnal average photochemical production and loss terms of ozone using monthly and zonally averaged limb infrared monitor of the stratosphere (LIMS) O3, H2O, HNO3, NO2, and temperature and stratospheric and mesospheric sounder (SAMS) CH4 data. The loss rates of ozone by pure oxygen species, by the nitrogen oxides, and by the hydrogen oxides are calculated along with the production rate of ozone by oxygen photolysis. The other major loss rate for ozone, which is the loss rate by the chlorine family, is calculated from a two‐dimensional model including SAMS CH4 measurements and a total Clx of 3 ppbv at the stratopause, yielding a ClO profile in good agreement with balloon measurements. All loss rates of ozone are therefore tied to experimental measurements. Ozone is thought to be in photochemical equilibrium at low latitudes near 2 mbar; however, our calculations show the diurnal average ozone loss to be about 40–60% higher than the production. Therefore photochemical models using LIMS H2O, HNO3, NO2, and temperature and SAMS CH4 will predict lower ozone concentrations than those measured by LIMS. Uncertainties in this region are a factor of 1.7 with the major contributions coming from the O3 measurements, the calculated photolysis of O3 to O(1D), and the calculated photolysis for O2.
Stratospheric positive ion composition measurements between 22 and 45 km: An updated analysis
Authors: Ingels J. , Nevejans D. , Frederick P. , Arijs E.
Published: February 2008

A set of results about the positive ion composition of the stratosphere, consisting of some recently obtained as well as some previously reported data, is presented and analyzed. It is compared with model calculations described in a companion paper. A review of the abundances of proton hydrates and nonproton hydrates shows that the latter most probably result from the presence of acetonitrile (CH3CN) in the atmosphere. The vertical mixing ratio profile of this gas deduced from positive ion composition measurements is in good agreement with a model based on the assumption that acetonitrile is released at the earth's surface and subsequently destroyed in the atmosphere by chemical reactions (mainly with hydroxyl radicals). The results of an analysis of the possible isotopic mass peaks of mass 96 (H+(CH3)(H2O)3) is not in contradiction with this conclusion.
Infrared band shapes and band strengths of CF2Cl2 from 800 to 1200 cm−1 at 296 and 200 K
Authors: Nguyen‐Van‐Thanh  , Rossi I. , Jean‐Louis A. , Rippel H.
Published: February 2008

Infrared profiles and strength measurements have been obtained at a spectral resolution of 1.6 cm−1 for the absorption bands of CF2Cl2 (fluorocarbon 12) from 800 to 1200 cm−1 at 296 and 200 K. A slight temperature dependence of the band strength seems to be observed for the ν3 + ν9 combination band and for the (ν3 + ν9) ν6 and (ν1) ν8 band systems. The low‐temperature band profiles become narrower and the Q branches stronger than they are at room temperature. In particular, for the ν6 band, which is important for atmospheric sensing, the absorption coefficient shows an enhancement of 30% between 296 and 200 K at the peaks of the Q branch. These room temperature and low‐temperature data may be useful for greenhouse calculations.
Seasonal behavior of NO2 in the winter stratosphere: Inferred NOx
Authors: Zawodny Joseph M. , Rusch David W.
Published: February 2008

The long‐term seasonal trend in NO2 density near 10 mbar, as measured by the Solar Mesosphere Explorer (SME), is compared to photochemical model predictions of the trend throughout the first 3 months of 1982. The general increase in the observed NO2 is found to be caused by a shift in the partitioning of odd nitrogen in favor of NO2. The model is also used to infer the odd nitrogen (NOx: NO + NO2 + NO3 + 2 × N2O5) mixing ratio, which is seen to decrease rapidly throughout the period. This rapid decrease is found to be caused in part by improper modeling of the photodissociation rate of NO2. Indirect measurements of the photodissociation rate of NO2 from SME show the rate to change with solar zenith angle at angles greater than 70°. Only when this dependence is taken into account do the variations in the odd nitrogen mixing ratio become consistent with theory.
Infrared flux parameterizations derived from climate changes in a three‐dimensional climate model
Authors: Gutzler David S. , Stone Peter H.
Published: February 2008

Output from four experiments with the Goddard Institute for Space Studies climate model, simulating climates ranging from ice age conditions to Mesozoic conditions, are used to test whether simple parameterizations of infrared (IR) emissions to space can be applied to annual average climate changes. The possible predictors of IR emissions examined are zonally averaged surface temperature, fractional cloud cover, average cloud top height, tropospheric lapse rate, and atmospheric moisture content. First, parameterizations are derived from latitudinal variations simulated by the model for the current climate. The simplest such parameterization, with IR emissions being a linear function of surface temperature alone, predicts the simulated climate changes in IR emissions, with errors of about 35%. Inclusion of additional regression terms derived from latitudinal variations in the current climate does not improve the prediction of changes in IR emissions. However, by deriving regressions from one climate change and applying them to the other changes, we demonstrate that adding a term describing lapse rate changes reduces the error in the predicted IR flux changes to between 25 and 30%. The lapse rate changes approximately follow the change in moist adiabatic lapse rate in the tropics and the change in the critical lapse rate for baroclinic adjustment in middle latitudes, unless the climate change is so large as to cause a qualitative change in the dynamical regimes. Only a very slight further reduction in the remaining error in the predicted changes in IR emissions was achieved by including an additional predictor, and there was no clear‐cut best choice for the additional predictor.
Gas filter radiometer for carbon monoxide measurements during the 1979 summer monsoon experiment (MONEX)
Authors: Reichle Henry G. , Wallio H. Andrew , Casas Joseph C. , Condon Estelle P.
Published: February 2008

The instrumental and data reduction techniques used in obtaining remote measurements of carbon monoxide during the 1979 Summer Monsoon Experiment are described. The form of the signal function (the variation of signal with altitude) and the impact of variations in the vertical distribution of carbon monoxide are discussed. Estimates of the experimental accuracy are made both by assessment of error sources through the use of numerical simulations and by comparison with concurrent measurements made by means of gas chromatography. It is found that the radiometric measurements tend to be about 9% lower than the direct measurements and to have a precision of about 8%.
Day and night profiles of tropospheric nitrous oxide
Authors: Cofer Wesley R. , Connors Vickie S. , Levine Joel S. , Edahl Robert A.
Published: February 2008

Daytime and nighttime vertical profiles of the tropospheric trace gas N2O were determined from grab sample collections off the Atlantic and Gulf coasts of Florida. The grab samples were collected during the week of October 7–13, 1984, from a Lear Jet during descent spirals over an altitude range of 12.5–0.3 km in approximately 1.2‐km intervals. During this period there were two distinct airflow regimes sampled: the surface boundary layer (<2 km), in which the wind direction was typically easterly; and the regime above the boundary layer, which was predominantly characterized by westerly flow. N2O mixing ratios, normalized to dry air, were determined from 148 daytime and nighttime samplings. N2O was found to be uniformly mixed at all altitudes at 301.9 ± 2.4 parts per billion by volume.
Derivation of photochemical information near 1 mbar from ozone and temperature data
Authors: Douglass Anne R. , Rood Richard B.
Published: February 2008

An analysis procedure has been developed for derivation of information about the photochemical behavior of ozone near 1 mbar by explicitly accounting for the dynamical transport terms in the continuity equation for perturbations from the zonal mean. The procedure is shown to be valid using data from a numerical transport model and is then applied to LIMS ozone and temperature data, using geostrophic winds to estimate the transport terms. The data study is restricted to March at 2, 1 and 0.7 mbar. Because the temperature deviations are dynamically produced, large temperature deviations are associated with significant ozone transport terms. The anticorrelation between the deviations of ozone and temperature disappears when the transport terms are small. The derived photochemical information is compared to photochemical theory. Although there is overall agreement in the magnitude as well as the latitude, altitude, and time dependencies, discrepancies are suggested which may be related to the long‐standing failure of photochemical models to calculate ozone accurately near 1 mbar. The theory suggests that the addition of Clx to the stratosphere will affect the relationship of ozone and temperature at 2 and 1 mbar. Comparison of the photochemical information derived from future ozone and temperature measurements with the results of the present analysis should provide a critical test of the photochemical scheme thought to describe the behavior of odd chlorine in the stratosphere.
Spectrum of atmospheric vertical displacements and spectrum of conservative scalar passive additives due to quasi‐horizontal atmospheric motions
Authors: Gage K. S. , Nastrom G. D.
Published: February 2008

This paper is concerned with the relationship between the spectrum of vertical displacements associated with the mesoscale spectrum of quasi‐horizontal motions in the atmosphere and the mesoscale spectra of scalar passive additives. This work is based on observations of mesoscale atmospheric wave number spectra of wind, temperature, and certain trace species sampled in the altitude range 9–14 km by commercial aircraft during the Global Atmospheric Sampling Program (GASP). The principal result is that the scalar spectra are reasonably consistent with a simple model in which scalar fluctuations are produced by quasi two‐dimensional motions acting in a plane inclined slightly to isentropic surfaces and to the isopleths of constant mixing ratio of trace species.
Stable carbon isotope ratios in atmospheric methane and some of its sources
Authors: Tyler Stanley C.
Published: February 2008

Ratios of 13C/12C have been measured in atmospheric methane and in methane collected from sites and biota that represent potentially large sources of atmospheric methane. These include temperate marshes (∼−48‰ to ∼−54‰), landfills (∼−51‰ to ∼−55‰), and the first reported values for any species of termite (−72.8 ± 3.1‰ for Reticulitermes tibialis and −57.3 ± 1.6‰ for Zootermopsis angusticollis). Numbers in parentheses are δ13C values with respect to PDB (Peedee belemnite) carbonate. Most methane sources reported thus far are depleted in 13C with respect to atmospheric methane (−47.0 ± 0.3‰). Individual sources of methane should have 13C/12C ratios characteristic of mechanisms of CH4 formation and consumption prior to release to the atmosphere. The mass‐weighted average isotopic composition of all sources should equal the mean 13C of atmospheric methane, corrected for a kinetic isotope effect in the OH attack of CH4. Assuming the kinetic isotope effect to be small (∼−3.0‰ correction to −47.0), as in the literature, the new values given here for termite methane do not help to explain the apparent discrepancy between 13C/12C ratios of the known CH4 sources and that of atmospheric CH4.
Kinetics of hydrogen peroxide‐sulfur(IV) reaction in rainwater collected at a northeastern U.S. site
Authors: Lee Y.‐N. , Shen J. , Klotz P. J. , Schwartz S. E. , Newman L.
Published: February 2008

The kinetics of the reaction of dissolved S(IV) with H2O2 was studied in freshly collected precipitation samples in order to examine whether there exist any important influences on this reaction from trace constituents present in natural atmospheric liquid water, that is, rainwater and snowmelt. The kinetic study was carried out on over 300 freshly collected precipitation samples obtained at Brookhaven National Laboratory, Long Island, New York, during the period from October 1983 to September 1985. The second‐order rate constant k(2), defined as −d[H2O2]/dt = k(2)[H2O2][S(IV)], which was determined using the precipitation samples covering pH range 3.3–5.6, was found to be linearly dependent on H+ concentration, conforming to results previously obtained with purified water. The observed scatter in rate constant (±30%, standard deviation) is comparable to interlaboratory scatter observed for purified water; the average rate constant is 15% less than values obtained in our laboratory using purified water at the same pH and ionic strength. The scatter and the systematic bias of the data were examined in terms of experimental techniques employed as well as chemical composition of the samples. Sample scatter is attributed in large part to uncertainty in measured pH. The difference in the average rate constant is small compared to the large scatter exhibited by the data. Causes of the negative bias were not clearly identified, but pH uncertainty, ionic strength, and the presence of formaldehyde were ruled out. The small negative bias observed on the kinetics of this reaction, however, is not expected to exert an appreciable effect on the extent of atmospheric SO2 oxidation, especially under conditions where the reagent concentrations are high, and the reaction tends to be complete within cloud lifetimes. The utilization of rate constants for this reaction, determined using purified water in numerical calculations and modeling, is therefore justified.
Mesoscale circulations initiated by melting snow
Authors: Lin Charles A. , Stewart Ronald E.
Published: February 2008

A linearized model is used to examine the dynamical effects of a mesoscale temperature perturbation in the lower troposphere. The perturbation is a result of nonuniform cooling of the environment by melting snow. An organized mesoscale thermal circulation develops, with strong vertical motions in the interior, outflow at low levels, and a return flow at upper levels. This circulation is similar to a sea breeze circulation but is forced by an elevated horizontal temperature gradient. A possible application to the problem of observed enhanced precipitation regions near a rain/snow boundary is considered.