bluuebunny/crossref_metadata_2025 huggingface dataset:
Evidence for counterflow to the west wind drift off South America
Authors: Neshyba Steve , Fonseca Tomás R.
Published: February 2008

An XBT section with station intervals of 11 km, from 45° to 35°S along 92°W, taken February 1979, provides the first clear picture of the meridional thermal structure across the west wind drift in this sparsely sampled transition zone. At least two mesoscale isotherm structures are found which show vertical excursions of up to 250 m over horizontal distances of about 70 km and vertical coherence to depths of sampling limit at 1600 m; locations appear coincident with major ridge features in the Chile Rise. The inferred westward flow patterns are evaluated as possible source mechanisms for the tongue of low‐salinity surface water known to extend westward from the Chile coast.
On the theory of deep flow in the Hudson Shelf Valley
Authors: Hsueh Y.
Published: February 2008

The time averaged near‐bottom current in the New York Bight for a selected 3‐day period is idealized as a steady state response to the mean wind at the John F. Kennedy International Airport and the mean inflow condition across the Long Island shelf. The idealization invokes potential vorticity conservation in a homogeneous ocean subject to a linear bottom friction and results in shelf currents whose longshore components are in general agreement with the averages of the observed. In the Hudson Shelf Valley, qualitative agreement with the observation is achieved in the onshore component which is directed nearly along the valley axis. Nearshore, within 40 km or so of the coast, the response is, to a substantial degree, wind driven. Nearshore upvalley mean flow is due partly to shore‐parallel wind stresses that are directed away from the valley and is due partly to topographic deflection of an alongshore current that is driven in part by the inflow condition and in part by the alongshore component of the mean wind stress. Because of the important role of bottom friction, an alongshore current driven by longshore winds undergoes sharper (and more realistic) deflection across the valley than does an alongshore current driven by the inflow condition.
Associations and mesoscale spatial relationships among rainwater constituents
Authors: Gatz Donald F.
Published: February 2008

In a search for clues to the nature of aerosol scavenging and precipitation formation processes in convective storms, daily rain samples were collected in networks of 80 or 85 open polyethylene containers near St. Louis during the summers of 1972–1975. Collected samples were filtered to separate soluble and insoluble materials, and both fractions were analyzed for a variety of constituents, including Li, Na, Mg, K, Ca, Fe, Zn, Cd, Pb, and SO4=. To investigate which element/solubility fractions had similar deposition patterns and how those patterns related to each other and to rainfall, individual storms were analyzed by factor analysis. The results showed that deposition patterns grouped consistently into four main types: (1) soluble soil elements, (2) insoluble soil elements, (3) soluble pollutant elements, and (4) insoluble pollutant elements. Differences between the deposition patterns of pollutants and soil elements may be accounted for by the distribution of sources, but differences between soluble and insoluble portions of the same element probably reflect important differences in scavenging and/or precipitation formation processes. These processes may be amenable to further investigation using techniques similar to those described in this paper.
Intermediate nepheloid layers observed off Oregon and Washington
Authors: Pak Hasong , Zaneveld J. Ronald V. , Kitchen J.
Published: February 2008

Two distinct kinds of particle maxima (nepheloid layers) were observed off Oregon in November 1977 and off Washington in October 1978 by an in situ light transmissometer: one in the thermocline in the euphotic zone and the other at intermediate depth well below the thermocline. The thermocline nepheloid layer is associated with well‐defined maxima of dissolved oxygen, chlorophyll‐a, and phaeophytin, and these associations suggest that the nepheloid layer is primarily composed of phytoplankton undergoing active photosynthesis. The intermediate nepheloid layer is found in connection with the bottom waters near the shelf break and shares some of the characteristic properties of the bottom water: high concentration of suspended particles, low concentrations of dissolved oxygen, chlorophyll‐a, and phaeophytin. The particle size distributions in the intermediate nepheloid layer are different from those in the clear water above the nepheloid layer but similar to those in the bottom nepheloid layer. Two hypotheses for the generation of intermediate nepheloid layers, settling and horizontal advection, are examined, and the data support the latter hypothesis.
Concentration distribution of methyl chloride in the atmosphere
Authors: Rasmussen R. A. , Rasmussen L. E. , Khalil M. A. K. , Dalluge R. W.
Published: February 2008

Electron capture gas chromatography techniques were used to obtain measurements of methyl chloride (CH3Cl) concentrations in the atmosphere, at latitudes ranging from about 65°N to 90°S. Most of the measurements were made over the Pacific Ocean. Average global concentrations within the boundary layer were found to be 815±25 pptv in 1977 and 755±37 pptv in 1978. Lower concentrations were observed above the boundary layer with average values of 629±23 pptv and 618±23 pptv in 1977 and 1978, respectively, within ±20° of the equator, the boundary layer concentrations were significantly higher than those above the boundary layer. The sources, the sinks, the budgets, and the latitudinal distributions of CH3Cl are discussed in the paper.
Measurement of the tropospheric and stratospheric SO2 distribution
Authors: Georgii H.‐W. , Meixner F. X.
Published: February 2008

The knowledge of the SO2 mixing ratio at the tropopause and in the lower stratosphere is necessary for understanding the formation and the existence of the stratospheric aerosol layer. A new chemiluminescence technique permitted the analysis of SO2 below 1 ng SO2/ml reaction liquid. The filtersampling technique enables a detection limit of (0.01±0.001) parts per billion by volume (ppbv) SO2. Comparisons with other methods were performed, and flight application problems are discussed. During 1977 and 1978, several aircraft ascents were performed, reaching up to 5.2 km into the stratosphere. In continental air masses the SO2 mixing ratio decreases strongly within the first 5 km, while in maritime air masses a nearly constant mixing ratio with altitude was observed. A mean value of 0.5 ppbv seems to be typical for layers above 6 km, and SO2 mixing ratios between 0.03 and 0.17 ppbv SO2 were found at the tropopause level, increasing slightly above the tropopause. The experimental results were compared with one‐dimensional model calculations.
Production of odd nitrogen in the stratosphere and mesosphere: An intercomparison of source strengths
Authors: Jackman C. H. , Frederick J. E. , Stolarski R. S.
Published: February 2008

This study intercompares several sources of odd nitrogen (ON) in the stratosphere and mesosphere (middle atmosphere) so as to place galactic cosmic rays (GCRs), nuclear explosions, lightning, solar proton events (SPEs), relativistic electron precipitation, meteors, and the downward diffusion of NO from the thermosphere in their proper context relative to the oxidation of nitrous oxide. Use of published measurements of O3 and N2O show that the source of ON owing to the reaction of O(1D) + N2O peaks between 25 and 35 km and is by far the largest source in an annually, globally averaged sense with a magnitude of 4.5×1034 molecules yr−1. At solar minimum the GCRs add about the same amount of ON as N2O oxidation (1.7×1033 molecules yr−1) for geographic latitudes greater than 50°. Nuclear explosions in 1961 and 1962 added 1.1 and 2.2×1034 NO molecules, respectively, to the total global ON content. SPEs produced more ON at latitudes above 50° than did N2O oxidation for the years 1958, 1959, 1960, and 1972. Analysis of available measurements shows the downward flux of NO from the thermosphere to be between 8 and 33% of the integrated N2O source. Large variations in measurements of ON should be expected at geographic latitudes above 50° where the highly variable SPE source of ON is substantial. Because of the long lifetime of ON in the middle atmosphere, significant variations in its content may also be expected to occur at mid‐latitudes.
Radon flux from the Earth: Methods of measurement by the nuclear track technique
Authors: Fleischer R. L.
Published: February 2008

The nuclear track technique, which can be used to measure concentrations of radon directly, can also be employed to determine radon flux by means of gradients in concentration in the ground, at its surface, or above the surface. Diffusional properties or emanation properties need to be assessed, but often can also be measured by track counting. Measurements at Thoreau, New Mexico, give a flux of 1.4 atoms/cm2−s over an area of 60,000 m2. At Scotia, New York, 1.1–1.2 atoms/cm2−s are measured over an area of 100 m2.
A free rossby wave in the troposphere and stratosphere during January 1979
Authors: Madden Roland A. , Labitzke Karin
Published: February 2008

A large‐scale (zonal wave number 1), westward‐propagating disturbance present in the troposphere and the stratosphere in January 1979 is shown to be similar to a free Rossby wave. Its vertical and horizontal structures are reasonably consistent with those of a theoretically predicted wave mode of the second class. It is similar to the so‐called 16‐day wave described earlier, and, therefore, not an unusual occurrence. It is argued that this traveling wave may be preferentially excited by random forcing and that it can interact with quasistationary waves forced by mountains and by heat sources. It is shown, for example, that this interaction can cause fluctuations in eddy heat transport throughout the atmosphere.
A note on Green's law
Authors: Witting James M.
Published: February 2008

Green's Law for the propagation of a linear nondispersive wave in a gradually varying medium conserves energy, which is a quadratic integral property. Green's Law does not conserve linear integral properties, and other waves must arise. This paper treats some general properties that these additional waves must possess for a class that includes long linear water waves in a channel of gradually varying section. The major finding is that both a reflected wave and a re‐reflected tail are required to satisfy all of the conservation laws; integral properties of these additional waves are derived.
Wave set‐up on a natural beach
Authors: Guza R. T. , Thornton E. B.
Published: February 2008

Wave set‐up, the superelevation of mean water level owing to the presence of breaking incident waves, was measured at the shoreline of a natural beach. Offshore pressure sensors monitored incident wave conditions. The set‐up of the shoreline was found to be about 0.17Hs,∞, where Hs∞ is the significant wave height in deep water.
Horizontal particle velocities in long waves
Authors: Svendsen I. A. , Staub C.
Published: February 2008

A general expression is derived for the horizontal particle velocities in long waves. The derivation is based on a polynomial expansion in the vertical coordinate z which results in an expression for u in terms of the surface elevation η and its derivatives. The result is valid for high waves but is in the preliminary form not directly applicable. It is shown, however, that for waves of relatively small amplitude to depth ratio the result corresponds to the well‐known cnoidal wave theory. The horizontal velocities predicted by that theory are then critically examined, and it is shown that there are conflicting properties, which imply that no cnoidal theory can be satisfactory for waves higher than 30–40% of the depth of water. Instead, a simple formula based on a parabolic truncation of the above‐mentioned polynomial in z is derived for the velocity under the crest of arbitrary high waves. The results are compared both with experiments and with stream function theory, and, particularly, the latter gives remarkably good agreement even for the highest waves.
Intrusion of loop current waters onto the West Florida continental shelf
Authors: Huh Oscar K. , Wiseman W. J. , Rouse Lawrence J.
Published: February 2008

An intrusion of loop current water up DeSoto Canyon and onto the West Florida continental shelf to within 8 km of the shore occurred in February 1977. Boat, aircraft, and satellite data collected in the area for another purpose were used to estimate the space and time scales of the intrusion and the ultimate fate of the intruded waters. The duration of the event was 18 days. Oceanic waters advanced across the shelf at speeds of 20 cm s−1. At maximum intrusion, 6650 km2 of shelf were affected. Approximately half the intruded water receded off the shelf, and half appears to have been modified in situ.
Comment [on “A reexamination of Bagnold's granular‐fluid model and bed load transport equation” by J. A. Bailard and D. L. Inman]
Authors: McTigue D. F. , Savage S. B.
Published: February 2008

Bailard and Inman (1979) have raised a number of important questions in their study challenging the classic work of Bagnold (1954) on the flow behavior of granular materials. However, we believe that neither the theoretical arguments nor the experimental results of Bailard and Inman offer compelling reasons to reject Bagnold's basic conclusions. In the following remarks, we shall address several spects of Bailard and Inman's work, retaining their notation for ease of comparison.
The two‐dimensional diagnostic model for tropospheric OH: An uncertainty analysis
Authors: Chameides W. L. , Tan A.
Published: February 2008

Tropospheric OH is believed to play a major role in atmospheric photochemistry, and, via its chemical interactions, OH ultimately may affect the climate, stratospheric ozone levels, and the pH of rain. A valuable tool for predicting the global OH abundance as a function of latitude and altitude is the two‐dimensional diagnostic model for tropospheric OH. This model can also be applied to budget studies of species which interact with OH, such as CH4, CO, and O3. In addition to laboratory‐obtained kinetic data, important variables, including the rate constants for several reactions, the rate of heterogeneous removal of soluble species, and the global abundance and spatial variability in H2O, O3, CO, and NOx. The uncertainties in these parameters imply over a factor of 3 variability in the calculated global OH concentration as well as significant uncertainties in the latitudinal and vertical OH distribution.
Seasonal variations in global sea level pressure and the total mass of the atmosphere
Authors: Trenberth Kevin E.
Published: February 2008

The annual cycles of sea level and surface pressures and the atmospheric pressure owing to water vapor have been analyzed in detail. Global sea level pressures undergo an annual cycle of 0.5 mbar range with a maximum in the northern winter. Global surface pressures, which represent the total mass of the atmosphere, also undergo an annual cycle of 0.5 mbar range but with the maximum in the southern winter. The changes in water vapor concentrations are responsible for the latter—water vapor has a maximum in the southern winter. The constancy of the mass of dry air is used as a check on the accuracy of computations. The total mass of the atmosphere is 513.7 × 1016 kg with a standard error of 0.02 × 1016 kg and an annual cycle of amplitude 0.1 × 1016 kg. The corresponding global mean surface pressure of the atmosphere is 984.68 mbar. The mean total mass of water vapor is 1.3 × 1016 kg which corresponds to 2.53 cm of precipitable water or 12906 km3 of water at 0°C. The distribution of pressure and mass as a function of latitude are also presented. A substantial annual exchange of mass occurs between the hemispheres amounting to 0.7 × 1016 kg of dry air (2.7 mbar range in hemispheric averaged pressure). Maximum pressures occur in winter, and the summer loss of mass is partially compensated for by increased water vapor amounts. The maximum net meridional flow occurs across 5°N in the transition seasons. In the northern hemisphere, water vapor undergoes an annual cycle with a range of 1.5 mbar (area averaged) and a summer maximum, and the sea level pressure owing to dry air undergoes an annual cycle of range 5 mbar and a winter maximum. Of this, 54% is due to exchanges with the southern hemisphere and 46% is due to changes in the artificial atmospheric mass used to correct from the surface to sea level.
Multifrequency radiometer detection of submarine freshwater sources along the Puerto Rican coastline
Authors: Blume Hans‐Juergen C. , Kendall Bruce M. , Fedors John C.
Published: February 2008

The surface area above submarine springs of fresh water exhibit temperatures and salinities lower than the surrounding sea waters. A multifrequency radiometer system which earlier demonstrated an accuracy of 1°C and l‰ in remotely detecting the surface temperature and salinities, respectively, was used to detect submarine freshwater springs. The first mission on February 4, 1978, consisted of overflight measurements over three fourths of the coastal areas around the island of Puerto Rico. During the second mission on February 6, 1978, special attention was directed to the northwest portion of Puerto Rico where several submarine springs had been reported. The previously reported spring locations correlated well with the locations detected by the radiometers. After separating the surface runoffs such as rivers, lagoons, marshes, and bays, 44 submarine freshwater springs were identified which indicates that the submarine freshwater outflow locations are more numerous around the island than had earlier been estimated. The majority of the submarine springs are located at the northwest and southeast portion of the Puerto Rican coastline. The success of detecting the same submarine springs during both missions at the northwest portion of the island was 39%.
Planetary waves and solar activity in the stratosphere between 50 and 10 mbar
Authors: Ebel A. , Schwister B. , Labitzke K.
Published: February 2008

The effects of solar activity on the geopotential height and temperature fields of the 50‐, 30‐ and 10‐mbar surface, resolved into zonal harmonic components, were investigated. This was done by means of cross‐spectral analysis between the 10.7‐cm radiation of the sun and planetary waves up to zonal wave number 3. Frequent significant responses of various harmonic components in a broad range of oscillation frequencies give evidence that solar activity plays a significant role for the dynamics of the middle and lower stratosphere. Oscillations of the amplitudes of the zonal harmonics that are coherent with solar activity fluctuations were extracted from the spectra and recomposed into coherent (planetary) waves. Three waves with periods of 25 days (near to the sun's rotation period), 13.6 days (first harmonic of solar rotation), and 15.1 days (corresponding to the well known 15‐ to 16‐day wave in the atmosphere) are examined in detail. They show the properties of free planetary modes (13.6 and 15.1 days) and possibly of internal waves (25 days) at higher latitudes. Vacillation cycles of the mean atmospheric state (including stationary waves) seem to be important for the generation of the studied wave phenomena.
222Rn and atmospheric electrical parameters in the Carlsbad Caverns
Authors: Wilkening Marvin , Romero Van
Published: February 2008

Atmospheric electrical parameters have been investigated in the Carlsbad Caverns. 222Rn concentrations of the order of 65 pCi/1 in the Caverns during the summer maximum results in a high rate of ionpair production estimated to be about 2300×106 ion pairs m−3 s−1. This leads to ion densities of about a thousand times that of the free atmosphere. Electrical conductivity values of approximately 150×10−14 (Ω m)−1 were measured which exceed those of outdoor air by a factor of the order of 100. Mobilities for positive and negative small‐ion populations in the Caverns during the summer, appear to be less than mobilities reported for small ions in the free atmosphere. The lower mobility of the cave ions relative to outdoor fair‐weather conditions is attributed to a combination of high humidity and low condensation nuclei concentration in the cave environment. An electric field of approximately 1 V m−1 was measured near the floor of a tunnel in the Caverns. This suggests the presence of net negative space charge equivalent to about 0.4×108 ion m−3.
Movable bed roughness in unsteady oscillatory flow
Authors: Grant William D. , Madsen Ole Secher
Published: February 2008

A model to predict the roughness in unsteady oscillatory flows over movable, noncohesive beds is presented. The roughness over movable beds is shown to be a function of the boundary shear stress, rather than a fixed geometrical scale as is the case for fully rough turbulent boundary shear flows over immobile beds. The model partitions the roughness into two distinct contributions. These two contributions are due to the form drag around individual bed forms and to the near‐bed sediment transport. The form drag over the bed forms is treated explicitly as a function of the boundary geometry and shear stress. The ripples are predicted as a function of the local skin friction, and a semiempirical expression is derived using standard law‐of‐the‐wall arguments, which gives the ripple or form roughness as a function of the boundary geometry. The ripple roughness is found to be proportional to the product of the ripple steepness and height. Favorable comparison of the form drag model with the results of Bagnold's (1946) fixed ripple study is found. The value of z0 associated with intense sediment transport in oscillatory flow over a flat bed is determined from Carstens et al.'s (1969) experiments. This value is found to be 7 or 8 grain diameters. An expression is derived for the roughness associated with the maximum thickness of a near‐bottom sediment‐transporting layer consistent with Owen's (1964) roughness hypothesis for saltation of uniform grains in air. At large values of the boundary shear stress relative to the critical value for initial sediment motion, the derived expression is similar to the results of Smith and McLean's (1977) unidirectional flow approach modified for oscillatory flow. The total roughness model is found to compare favorably with Carstens et al.'s (1969) data. In contrast to Smith and McLean's (1977) steady flow findings, the results here show that when ripples are present, they account for a significant portion of the boundary roughness.
Mesospheric water vapor
Authors: Deguchi S. , Muhleman D. O.
Published: February 2008

Water vapor in the earth's mesosphere has been observed at the frequency of 22.235 Ghz as an absorption against the sun by utilizing a ground‐based radio telescope. The H2O mixing ratio of 4.3±1 ppm is obtained in the height 40–70 km for a constant distribution model. The data are equally well represented by a photochemical model of Crutzen (1974), which was scaled by a factor of 0.93 yielding a peak mixing ratio of 6±1 ppm at 55 km. These results are 3‐day averages during November 1979, where the averaging periods cover the about ±4 hours of the sun's transit of our meridian. The measurements are insensitive to H2O above 70 km, where the absorption is very weak. We cannot estimate the mixing ratios below 50 km, since the pressure broadening in the line exceeds the bandwidth of our spectrometer at the lower altitudes.
Evidence for aqueous phase hydrogen peroxide synthesis in the troposphere
Authors: Heikes B. G. , Lazrus A. L. , Kok G. L. , Kunen S. M. , Gandrud B. W. , Gitlin S. N. , Sperry P. D.
Published: February 2008

Recent studies of the oxidation of sulfur dioxide by hydrogen peroxide in solution indicate that this process may be the dominant mechanism for the conversion of SO2 to H2SO4 in cloud water where the typical pH is less than 5.5. In the interpretation of theoretical calculations and previous hydrogen peroxide measurements it has generally been assumed that the limiting factor in the acidification of precipitation is the amount of gas‐phase H2O2 available to the cloud‐precipitation system. Field observations of H2O2 during Acid Precipitation Experiment (APEX) missions revealed that in addition to vapor phase H2O2, there were present one or more atmospheric constituents which produced H2O2 in the aqueous phase, and there were other species which consumed the collected H2O2 vapor. We report here an investigation of these phenomena undertaken to ensure that the instrumentation was responding to H2O2 alone and to identify the species which interfered in the aqueous collection and measurement of H2O2 vapor. Our results showed that (1) the H2O2 found within the collectors frequently exceeded the amount initially present as vapor, (2) the species which produced H2O2 were relatively insoluble, (3) NO2 did not enhance H2O2 formation, (4) O3 enhanced H2O2 formation, and (5) SO2 depleted aqueous H2O2. The amount of aqueous H2O2 lost when SO2 vapor was added to ambient air was larger than expected. The results of these experiments have important implications for cloud water chemistry. If the processes occurring within the impinger can be extrapolated to droplets, the amount of H2O2 available for SO2 oxidation would not be limited by the amount of H2O2 vapor in precloud air but would also depend upon the concentration of the precursors capable of generating H2O2 in droplets.
Impurity sources Of F−, Cl−, NO3− and SO42− in Greenland and Antarctic precipitation
Authors: Herron Michael M.
Published: February 2008

Five polar impurity sources are proposed: anthropogenic NO3− and SO42− in recent Greenland but not Antarctic snow; marine aerosols, the dominant Cl− source; volcanic eruptions, which produce detectable but variable peaks in SO42−, F−, and/or Cl− concentrations; biogenic sulfurous gases from soil and coastal waters, the dominant source for SO42− in nonvolcanic strata; an unidentified source of background nitrate which is more active in the northern hemisphere and which displays a summer concentration maximum. Solar activity and supernova events do not modulate NO3− concentrations in Greenland snow.
Acoustic and radar sea surface backscatter
Authors: McDaniel Suzanne T. , Gorman Arthur D.
Published: February 2008

Theoretical predictions of sea surface reverberation are compared with representative acoustic and radar data to determine those mechanisms responsible for backscatter. Predictions of the composite roughness scattering model are compared with data in three frequency ranges, 2–5 kHz acoustic (428‐and 1228‐MHz radar), 20–25 kHz acoustic (4455‐MHz radar), and 58–60 kHz acoustic (8910‐MHz radar). The predicted backscattering strength is found to be in relatively good agreement with the radar data at all frequencies; however, only at the lowest frequency do the predictions match the acoustic data. At the two higher frequencies, the measured acoustic backscatter greatly exceeds the composite roughness predictions at low grazing angles. To account for this discrepancy, a simple model is used to compute the reverberation due to a near‐surface bubble layer. The computed bubble contribution is shown to provide good agreement with the acoustic data and also to predict the saturation that occurs with increasing wind speed.
Evidence for the influence of form drag on bottom boundary layer flow
Authors: Chriss T. M. , Caldwell D. R.
Published: February 2008

An experiment in 199 m of water on the Oregon shelf produced continuous current speed profiles down to the sediment‐water interface. These profiles show that the velocity structure above the viscous sublayer is consistent with that expected when form drag influences the boundary layer flow. They show two logarithmic‐profile regions, each yielding a different stress estimate. The stress calculated from the upper one reflects the influence of form drag and is more than 4 times the bed stress determined frm the shear in the viscous sublayer. When form drag is significant, the application of logarithmic profile or Reynolds stress techniques to measurements more than a few tens of centimeters from the bed may yield bed stress estimates inappropriate for use in near‐bed sediment transport or entrainment calculations. Large roughness‐length or drag‐coefficient values do not prove that a viscous sublayer does not exist.
Long‐term means and short‐term variability of the surface energy balance components at the South Pole
Authors: Carroll J. J.
Published: February 2008

On the basis of a nearly continuous data set obtained between April 1975 and December 1977, a summary of seasonal means of the directly measured and calculated energy fluxes and examples of the short‐term (daily) variability in these components in response to changing synoptic conditions are presented. The seasonally averaged observations are consistent with those of previous studies, indicating that throughout most of the year a net radiative loss from the surface occurs averaging 12 to 13 W m−2 per year. In summer, the downward flux of heat from the air (Hs) exceeds the net radiation losses by 10–20%, resulting in storage of heat in the deep snowpack. In winter the radiative losses average between 16 and 20 W m−2 with Hs supplying 85–90% of this loss and the remaining 10–15% supplied from deep storage in the snow. On daily time scales, the energy balance components are highly variable, with ranges several times their long‐term means. This variability appears to result from variation in forcing associated with variations in the large scale flow, namely, changing large‐scale pressure gradient, cloudiness, and variations in the mean temperature of the lower atmosphere (i.e., Z ≲ 1 km).
Diurnal variations of minor constituents in the stratosphere modeled as a function of latitude and season
Authors: Fabian P. , Pyle J. A. , Wells R. J.
Published: February 2008

Photodissociation and collision processes in the atmosphere cause significant diurnal variations of short‐lived minor constituents, in particular among the group of catalysts HOx, NOx, and ClOx. Results of diurnal variation experiments within the framework of the Oxford zonally averaged model are presented. With 49 collision reactions and 13 photodissociation reactions, the model incorporates the most important processes known at present. The model extends from pole to pole and from the surface to about 60 km with a resolution of π/19 in the horizontal (∼9.5°) and half a pressure scale height in the vertical (∼3.5 km). The basic time increment for the integration is 5 min. Results are compared with experimental data.
The origin of continental shelf and slope water in the New York Bight and Gulf of Maine: Evidence from H218O/H216O ratio measurements
Authors: Fairbanks Richard G.
Published: February 2008

The H218O/H216O ratio of meteoric water in eastern North America decreases with increasing latitude. The annual weighted average δ18O content of the Middle Atlantic Bight (MAB) and Gulf of Maine (GOM) rivers are −9.33‰ and −10.89‰, respectively. The δ18O compositions of the major east coast rivers are 2‰ enriched during summer months. By using H218O and salinity measurements, both conservative properties of sea water, the geographic origin of continental shelf water can be identified. The isotope‐salinity tracer method, which has been used so successfully in polar regions, is also an effective method in the temperate MAB because subpolar waters are exported to this region. The apparent dilutent of slope water is −22‰ δ18O relative to standard mean ocean water. Water of this composition is presently forming in the Labrador Sea. Melt water from sea ice has nearly the same isotopic composition as the sea water from which it formed and thus may be distinguished from meteoric water. In March 1977, the New York Bight cold pool contained as much as 2.5% sea ice melt water. The Gulf of St. Lawrence is the nearest source of sea ice. The New York Bight ‘cold pool’ was renewed from the north between March and July, which was the extent of our sampling period.
The input of atmospheric n‐C10 to n‐C30 alkanes to the ocean
Authors: Duce Robert A. , Gagosian Robert B.
Published: February 2008

There are few data on organic compounds in the marine atmosphere. The only class for which any significant data base exists is the n‐alkanes. Using available data on n‐C10 to n‐C30 alkanes in aerosols, rain, and in the gas phase from Atlantic, Pacific, and Indian Ocean regions, crude estimates of the deposition of n‐alkanes to the world ocean are made. Deposition of gaseous and particulate n‐alkanes by rain scavenging, of particulate n‐alkanes by dry deposition, and of gaseous n‐alkanes by direct vapor exchange with the ocean are evaluated. Rain scavenging of particulate n‐alkanes appears to be the primary transport path to the ocean from the atmosphere. The total input of n‐alkanes to the ocean from the atmosphere is estimated to be from 0.04 to 0.4 Tg/yr. The accuracy of these estimates could be evaluated by the analysis of carefully collected rain samples over several oceanic regions. More precise estimates of the atmospheric input of organic material to the ocean will have to await more information on the inputs of the various organic compound classes to the sea surface and further understanding of the reaction products, pathways, and rates of transformation of these compounds in the atmosphere.
The origins of sulfur compounds in the atmosphere of a zone of high productivity (Gulf of Guinea)
Authors: Delmas Robert , Servant Jean
Published: February 2008

Recent observations have suggested substantial emission of sulfur compounds by oceanic water which could explain the presence of SO2 and SO=4 in the air above these waters. The emission is thought to increase with the productivity of the oceanic zones. This point is discussed in relation to the Gulf of Guinea, a zone of high productivity. During the first two campaigns between Dakar, Abidjan, and the Gulf of Guinea SO=4 concentrations were measured in the air. Between Abidjan and the Gulf of Guinea the atmospheric SO=4 concentrations decreased from 800 to 400 ng m−3.

During the third campaign, between Abidjan and the South Equatorial Current (latitude 1°S), the H2S and SO2 concentrations were measured. The mean H2S concentration was 20 ng m−3, and that of SO2 varied between 120 and under 50 ng m−3. The origins of SO2 and SO=4 in the air of this area are discussed through the daily variations of the H2S content of the air and a contribution from the forested zones of West Africa.
Particles and gases in the emissions from the 1980–1981 volcanic eruptions of Mt. St. Helens
Authors: Hobbs Peter V. , Tuell Jason P. , Hegg Dean A. , Radke Lawrence F. , Eltgroth Mark W.
Published: February 2008

Detailed airborne measurements of particles and gases were made in the volcanic effluents from Mt. St. Helens from March 1980 through August 1981. The results of these measurements are summarized and are used to deduce emission fluxes of particles and gases from the volcano. Measurements on the periphery of the plume of effluents produced by the violent paroxysmal eruption of May 18, 1980, showed number concentrations of particles <2 μm and >2 μm in diameter up to 1500 and 20,000 times greater, respectively, than in the ambient air. Mass concentrations of particles in the periphery of the plume on May 18 were ∼7000 μg m−3 with particles >2 μm making the dominant contribution. However, the percentage of the total mass in particles <2 μm increased with time after May 18 and was ∼100% of the emissions after June 18, 1980. The fluxes of particles from Mt. St. Helens ranged from 1020 s−1 during the May 18 eruption to 2×1015 s−1 in phreatic emissions. The particulate mass fluxes ranged from 6×104 to 10−2 kg s−1. The total input to the atmosphere of particulate mass from Mt. St. Helens from March 28, 1980, to March 28, 1981, is estimated to be ∼2 Tg. A sometimes substantial, but highly variable, percentage (0–91) of the mass of material in the plume of effluents consisted of soluble halides and sulfates. Fluxes of cloud condensation nuclei (active at 1% supersaturation) in the plume from the volcano ranged from 1016 to 2×1017 s−1. Gases in the effluents included H2O, SO2, H2S, CO2, N2, NO, CO, CH3, Cl, COS, and CS2. An unusually high percentage (35–100) of the sulfur was H2S, particularly during the paroxysmal and intraeruptive periods. Ozone was depressed below ambient values in the plume. SO2‐to‐SO4 = and NO2‐to‐NO3− conversions were observed in the plume at rates of ∼0.1–1% h−1. About 1% of the total material in the tropopause plume from Mt. St. Helens on May 18, 1980, was estimated to have reached the stratosphere. This yields estimates for the stratospheric injections on May 18, 1980, of 3×109 (and 1.5×108) kg of H20, 1.3×105 (and 6×104) kg of particles <2 μm, 1×1018 (and 1×1018) Aitken nuclei, 6×104 (and 3×104) kg of SO2, 3×104 (and 3×104) kg of H2S, 4×109 (and 1×109) kg of CO2 and 3×107 (and 3×107) kg of CO where, in each case, the first number is the total injection (i.e., volcanic plus entrained tropospheric material) and the number in parentheses is the material that derived from the volcano itself.
Time‐resolved emission studies of vibrationally excited hydroxyl radicals: OH(X2π, v″=9)
Authors: Greenblatt Gary D. , Wiesenfeld John R.
Published: February 2008

Vibrationally excited hydroxyl radicals OH(v″=9) are produced following the laser photolysis of 03/H2/He mixtures at 248 nm. The temporal profile of OH(v″=9) density was monitored by observation of the Δv=6 emission near 625 nm. Variation of the ozone pressure yields an estimate of the rate of vibrational relaxation of OH(v″=9) by 03, k ≈ 2 × 10−10 cm3 molecule−1 s−1. Comparison of the observed overtone emission intensity with that arising from the 0(21D2) precursor at 630 nm yields a factor‐of‐two estimate of the Einstein coefficient for spontaneous emission, A9→3 ≈ 0.006 s−1. This is in agreement with a previous experimental study, but does not support a theoretical value that has been extensively utilized in modeling of atmospheric Meinel emission intensity.
Feedback mechanisms in the climate system affecting future levels of carbon dioxide
Authors: Kellogg William W.
Published: February 2008

The rate of increase of concentration of atmospheric carbon dioxide depends on the consumption of fossil fuels (the major source of ‘new’ carbon dioxide) and the natural sinks for this trace constituent, primarily the oceans and the biosphere. (It is now fairly well established that the biosphere cannot be a major source, as has been claimed.) The rate of operation of these sinks depends on several factors determined by the state of the climate system, and they will therefore presumably change as the greenhouse effect of increasing carbon dioxide warms the earth. Five specific feedback loops are discussed, two of which are positive (amplifying the rate of increase), two are weakly negative (damping the rate of increase), and one is indeterminate but probably positive. It is concluded that it would be well to be prepared for the possibility that carbon dioxide may increase faster than predicted by models based on the current or past state of the climate system.
The sources of sulfate in precipitation: 1. Parameterization scheme and physical sensitivities
Authors: Hegg Dean A.
Published: February 2008

The parameterization scheme for sulfate washout derived by Scott [1978] is modified to allow estimation of the relative contributions of nucleation scavenging, in‐solution production, and below‐cloud scavenging to the sulfate content of precipitation. The parameterization scheme predicts changes in precipitation sulfate concentration by up to a factor of 6 for large variations in key cloud physics parameters. The results suggest in‐solution sulfate production can be a substantial contributor to the sulfate content of precipitation.
The sources of sulfate in precipitation: 2. Sensitivities to chemical variables
Authors: Charlson Robert J. , Vong Richard , Hegg Dean A.
Published: February 2008

A convective cloud model used to examine the relative contribution to sulfate in rain of nucleation scavenging (NS) below‐cloud scavenging (BCS) and in cloud production of sulfates (SP) shows that considerable variation may be expected due to change in the amounts of input sulfur species. The case of high input of both SO2 and SO4= bearing aerosol (industrial case) shows SP to be dominant while low inputs yield results ranging from NS and SP being roughly equal to dominance by NS. For the conditions chosen, BCS is low. The sensitivities of the partitioning between these three pathways to changes in SO2, SO4= aerosol, and pH are briefly surveyed.
Revised parameters for modeling the transport of PCB components across an air water interface
Authors: Bopp Richard F.
Published: February 2008

A number of revisions of the data base and conceptualizations utilized in air‐water transport models for PCB components are suggested. The most significant of these involves the assignment of physical chemical properties on the basis of degree of chlorination. The effect of temperature on the rate of transport is also discussed. The revised model is tested on a number of natural situations and compared with available data.
Wind drag coefficient over first‐year sea ice in the Bering Sea
Authors: Macklin S. Allen
Published: February 2008

Profiles of relative wind speed and temperature were collected from four levels over rough sea ice in the marginal ice zone of the Bering Sea and used to compute surface wind drag coefficients. Based upon 138 profiles for near‐constant ice conditions, northeast winds of 3–15 m s−1, and near‐neutral stability, the mean, near‐neutral, 10‐m drag coefficient was 0.00309±0.00049. This is among the largest drag coefficients measured for neutral atmospheric conditions over sea ice. Sixty‐five percent of the variance of this estimate is explained by orientation of the ice floe to the wind; an additional 5% of the variance is explained by wind‐speed dependence. Provided that diabatic atmospheric stability over the Bering Sea ice pack is well correlated with low wind speed, the significant ice‐advecting wind stress on the ice is determined from the neutral value of the drag coefficient, a function of ice roughness length alone. The ice forecaster thus may use remote measurements or estimates of wind speed and surface roughness to assess the wind component of ice advection.
A deconvolution of the tree ring based δ13C record
Authors: Peng Tsung‐Hung , Broecker Wallace S. , Freyer Hans D. , Trumbore Susan
Published: February 2008

We assumed that the tree‐ring‐based 13C/12C record constructed by Freyer and Belacy (1983) to be representative of the fossil fuel and forest‐soil induced 13C/12C change for atmospheric CO2. Through the use of a modification of the Oeschger et al. ocean model, we have computed the contribution of the combustion of coal, oil, and natural gas to this observed 13C/12C change. A large residual remains when the tree‐ring‐based record is corrected for the contribution of fossil fuel CO2. A deconvolution was performed on this residual to determine the time history and magnitude of the forest‐soil reservoir changes over the past 150 years. Several important conclusions were reached. (1) The magnitude of the integrated CO2 input from these sources was about 1.6 times that from fossil fuels. (2) The forest‐soil contribution reached a broad maximum centered at about 1900. (3) Over the 2 decade period covered by the Mauna Loa atmospheric CO2 content record, the input from forests and soils was about 30% that from fossil fuels. (4) The 13C/12C trend over the last 20 years was dominated by the input of fossil fuel CO2. (5) The forest‐soil release did not contribute significantly to the secular increase in atmospheric CO2 observed over the last 20 years. (6) The pre‐1850 atmospheric
values must have been in the range 245 to 270×10−6 atmospheres.
Deductions concerning accumulations of electrified particles in thunderclouds based on electric field changes associated with lightning
Authors: Vonnegut B.
Published: February 2008

The relationships between the space charge in thunderclouds and the lightning that it causes are so complex or so poorly understood that deductions concerning the nature or location of this charge based solely on observations of lightning are open to question.
Resuspension of volcanic ash from Mount St. Helens
Authors: Hobbs Peter V. , Hegg Dean A. , Radke Lawrence F.
Published: February 2008

Measurements are presented of the size spectra of ash particles, previously deposited on the ground from the May 18, 1980 eruption of Mount St. Helens, that were resuspended into the air in eastern Washington. It is concluded that winds of just a few meters per second were capable of resuspending most of the smaller ash particles and that this caused dramatic reductions in visibility.
Subsurface energetics of the Gulf Stream cyclonic frontal zone off Onslow Bay, North Carolina
Authors: Hood Carroll A. , Bane John M.
Published: February 2008

It has been shown with the use of 4‐month‐long time series of velocity, temperature, and conductivity that fluctuating kinetic and potential energy was converted into kinetic and potential energy of the mean flow following a fluid particle in the subsurface Gulf Stream cyclonic frontal zone off Onslow Bay, North Carolina, during early 1979. This result agrees well with earlier measurements made in the surface layer off Onslow Bay. These flux calculations represent an important step in verifying the direction of the net cross‐stream energy flux within the stream off Onslow Bay. According to an hypothesis presented for the growth and decay of Gulf Stream meanders along the continental margin of the southeastern United States, Onslow Bay is an area of decreasing meander amplitude. The direction of the energy conversion from meanders to the mean flow, determined from our calculations, is consistent with this hypothesis. Relatively low velocity covariances were found to be associated with relatively small transfers of kinetic energy during a period of low meander activity. This finding supports the notion that meanders play a significant role in the energy transformation processes. The presence of such ‘quiet’ periods may indicate a low‐frequency modulation of Gulf Stream meander activity.
Droplet phase (Heterogeneous) and gas phase (homogeneous) contributions to secondary ambient aerosol formation as functions of relative humidity
Authors: McMurry P. H. , Wilson J. C.
Published: February 2008

In previous publications (McMurry and Wilson, 1982; McMurry et al., 1981), techniques for determining the relative contributions of gas phase and liquid phase reactions to secondary ambient aerosol formation have been described. In this paper these methods are applied to more recent data acquired during the 1980 Environmental Protection Agency PEPE‐NEROS study near Columbus, Ohio. It is shown that liquid phase reactions tend to be the most important mechanism of sulfate aerosol formation for relative humidities greater than 75%, while gas phase reactions are predominant at lower humidities. In either case, although measurements have been made both during daylight and nighttime hours, aerosol formation has been observed only in air parcels exposed to sunlight. Gas phase conversion rates typically varied between 0 and 5% hr−1, but liquid phase contributions as high as 12% hr−1 were observed in the Columbus urban plume. Liquid phase reaction rates (moles of SO2 oxidized (volume of liquid)−1 ppb SO2−1 time−1) are determined and are shown to increase with increasing relative humidities.