Diurnal Variation Of Ozone Research Articles

Oxides of nitrogen at two sites in New Zealand

Oxides of nitrogen, ozone and solar UV radiation were measured at two New Zealand sites, four months at Mt. John near Lake Tekapo, and one month at the New Zealand Department of scientific and Industrial Research, Physics and Engineering Laboratory Atmospheric Station (PELAS) near Lauder. The former site proved ideal for clean‐air measurements. Ozone concentrations of ∼20‐25 ppb, with little diurnal variation were accompanied by total nitrogen oxide (NOy) levels frequently less than 150 ppt (parts in 1012 by volume). The noon NO and NO2 data were well correlated with a slope comparable to model values. Gaseous HNO3 was observed to be significantly above the noise level (∼15 ppt) for only twenty‐seven four‐hour averages. For these a median of 43 ppt was obtained with a median ([NOy]‐[HNO3])/[HNO3] ratio of 7.5, not comparable with model values of around 1.1. This low HNO3 may arise from the fact that the Mt. John site is downwind of a mountain range which experiences significant upwind precipitation. At the PELAS site, strong diurnal variation of ozone and much larger NOy concentrations were observed. The difference is apparently caused by local sources of nitrogen oxides and the local meteorology at the fertile valley PELAS site.

Observation of the diurnal variation of atmospheric ozone

Ozone densities in the stratosphere and mesosphere have been derived from broad‐band photometer measurements of Hartley band absorption of middle ultraviolet radiation. Seven rockets were launched during October–November 1979 from Wallops Island. Six rockets, each carrying one detector comprising two UV photometers, were launched at different times of the day. A seventh rocket, with three similar detectors each having three UV photometers, was launched at the time of a full moon and provided estimates of the nighttime ozone densities. Results from these rocket flights form a basis for investigating ozone diurnal variations. The number of flights provide greater statistical reliability for the ozone profiles than is generally afforded from in situ measurements with a single rocket. During the night, an enhancement in ozone densities occurred at altitudes above about 50 km. At 70 km, for example, the nighttime ozone was determined to be a factor of 6.4 greater than at sunset. In addition, these experiments suggest that near 40 km the magnitude of the ozone density at noon may be greater by 10–15% than the nighttime concentration.

Diurnal variation of mesospheric ozone

Photochemical models1–3 predict a considerable variation in ozone concentration between day and night in the mesosphere. To investigate this, four Petrel rockets were flown from South Uist (57°22′N, 7°22′W) on 2 October 1979. Ozone was measured by observing the atmospheric attenuation of a narrow band of UV radiation, using interference filters to define a bandwidth of ∼10 nm. The rockets were launched (1) at moon-set, 02.00h, (2) at sunrise, 06.00h, (3) at 09.30h and (4) at 15.30h; round 1 observing moonlight and the other three observing sunlight. The first two used the occultation technique4 and contained two photometers with wavebands centred around 265 and 290 nm (Fig. 1), giving ozone information from 48 to 95 km. For rounds 3 and 4 the Sun was at a zenith angle of 70°, and a single waveband centred around 265 nm gave a height range of 44 to 64 km. Full details of the experiment will be published elsewhere. The first three rounds were successful, but the fourth did not give good data because the rocket nosecone failed to clear the field of view. The results show significant diurnal variation above 54km, which exceeds a factor of 2 above 65 km and reaches a factor of 10 between night time and sunrise at 90 km.

Destruction of ozone at the earth's surface

Several hundred new measurements of the surface resistance to ozone uptake of grass, soil, sand, fresh water, sea water and snow are presented. Grass and soil show, in agreement with previous work, a daytime surface resistance of median value 100 sm−1. The first direct evidence is presented of a nocturnal increase in surface resistance for grass and soil, with night-time values of surface resistance of about 300 sm−1. The surface resistances of sea water and snow are considerably larger, about 1000 to 2000 sm−1. A representative global ozone destruction rate for the earth's surface is derived using the above information and other published ozone data. Allowance is made for the latitudinal variation of the different types of surface, their various ozone destruction constants, the latitudinal and diurnal variation of ozone in the surface air and the diurnal variation of eddy transfer near the earth's surface. The global average ozone destruction rate is estimated to be in the range 2 to 6 × 1029 molecules s−1 (0.5 to 1.5 × 1012kg yr−1). This range extends to slightly higher values than previous estimates. The ratio of ozone destruction rate between the southern and northern hemispheres is about 2:3. The implications for the tropospheric ozone cycle are discussed.

Destruction of ozone at the earth's surface

AbstractSeveral hundred new measurements of the surface resistance to ozone uptake of grass, soil, sand, fresh water, sea water and snow are presented. Grass and soil show, in agreement with previous work, a daytime surface resistance of median value 100 sm−1. The first direct evidence is presented of a nocturnal increase in surface resistance for grass and soil, with night‐time values of surface resistance of about 300 sm−1. The surface resistances of sea water and snow are considerably larger, about 1000 to 2000 sm−1. A representative global ozone destruction rate for the earth's surface is derived using the above information and other published ozone data. Allowance is made for the latitudinal variation of the different types of surface, their various ozone destruction constants, the latitudinal and diurnal variation of ozone in the surface air and the diurnal variation of eddy transfer near the earth's surface. The global average ozone destruction rate is estimated to be in the range 2 to 6 × 1029 molecules s−1 (0.5 to 1.5 × 1012kg yr−1). This range extends to slightly higher values than previous estimates. The ratio of ozone destruction rate between the southern and northern hemispheres is about 2:3. The implications for the tropospheric ozone cycle are discussed.

Diurnal variations of ozone and other pollutants in an urban area

A theoretical model is used to describe the diurnal variations of primary and secondary pollutants, with emphasis on ozone. This is done for an urban basin with anthropogenic sources of nitrogen oxides and hydrocarbons. We propose a scheme for the decomposition of aromatic compounds. According to this scheme, each aromatic molecule gives rise to six transfers of NO to NO 2 without consumption of odd oxygen. It is concluded that it is not a good approximation to represent urban hydrocarbon emissions by one single species, neither in short term (a few hours) nor multiday simulations. Species with both high and low reactivity ought to be included. We show that the nocturnal minimum in ozone often observed in urban areas, is mainly induced by gas chemistry. It is not a good approximation to omit the chemical development during the night-time in a theoretical analysis of urban photochemical pollution. Such an omission introduces errors also in the day-time chemistry. Application of constant dissociation rate coefficients over the day gives rise to false morning and evening ozone maxima.

A time-dependent photochemical model for ozone near the ground

We present a time-dependent photochemical model of tropospheric ozone. In accordance with our previous calculations (Chameides and Walker, 1973) we treat ozone as an active chemical constituent with a local abundance that is determined by photochemical processes rather than by transport processes. The local abundance of odd nitrogen is shown to play a major role in determining the intensity of photochemical production and destruction of ozone, a large local abundance of NOx (= NO + NO2) leading to large diurnal ozone variations. The photochemical model is shown to reproduce the diurnal variations of ozone and nitrogen dioxide observed near the ground at Research Triangle Park in North Carolina.

The effect of ionic processes on the characteristics of radio-echoes from meteor trains

The effect on meteoric ionization of known ionic reactions of possible relevance has been assessed. It is shown that oxidation of positive meteoric ions by molecular oxygen and ozone, and the formation of nitride ions, followed in each case by dissociative recombination, can give rise to a pseudo-three-body attachment, which for reasonable ozone concentrations in the meteor region is sufficiently rapid to explain observed deionization. The difference between daytime and night-time rates is attributable to the diurnal variation of ozone. It is also shown that direct recombination with meteoric ions (whether hydrated or not) is too slow to be important, and that positive atmospheric ion-molecules, which are capable of participating in rapid recombination, are probably never formed in significant numbers. True attachment and associated negative ion processes are found to be generally unimportant in meteor trains, except possibly below ~80 km at night, where significant attachment, leading eventually to the formation of complex radicle ions, is feasible. The reversal of this ionization over the sunrise period, due to various detachment processes, could influence the detailed transition from night to daytime conditions. A comparison of the observed changes in integrated duration of echoes from Quadrantid shower meteors over the sunrise period with theoretical expectation confirms that the “attachment” rates previously obtained by the authors (see below) are of the correct order of magnitude. Reasons for the discrepancies between these rates and the higher rates found by other workers are discussed. Quantitively, we may conclude that the maximum ionization of a 5th magnitude meteor travelling at 40 km s −1 occurs between 90 and 95 km, and hence that the apparent attachment rate at a reference height of 95 km most probably lies in the range 0.0003–0.001 s −1 during the day, and 0.001–0.003 s −1 during the night. Ozone height profiles consistent with these conclusions are proposed for day and night conditions. The suggested ozone concentrations lie within the range of previously measured values, and the profile shapes are in good qualitative agreement with the predictions of photochemical theory.

Ozone concentration studies near the ground at Poona Part II : Short term fluctuations

The paper discusses short term fluctuations, superimposed on the diurnal variation of surface ozone recorded at Poona during 1969.1970, in association with thunderstorms and the breakdown of temperature inversions near the ground.
 While there is a net production of ozone during electrical discharges in a thundercloud, the surface ozone recorder at Poona often registered a decrease in surface ozone concentration. This decrease coincided with the Bay of Bengal updrafts generated during the formation and movement of a thunderstorm. Similar sharp increases in ozone were observed with downdrafts. In cases of lightning without the appearance of thunderstorm over the station, an increase in ozone density was observed immediately after the first lightning discharge.

Short-term ground ozone fluctuations at Poona

Short-term fluctuations superimposed on the diurnal variations of surface ozone recorded at Poona during 1969–1970 are discussed.

Photochemical Ozone Formation in the Atmosphere over Southern England

ATKINS et al.1 present evidence of photochemical ozone formation in the atmosphere over southern England. When, however, the diurnal ozone variation is carefully examined, some doubt may be felt whether all the ozone measured was indeed locally generated. The data given by Atkins et al. include thirteen days where pronounced ozone peaks could be observed and in all these cases the maxima occurred in the late afternoon, between 1600 and 1700 BST. These late afternoon maxima are not in accord with the predicted diurnal variation of photochemically produced ozone; the daily maxima should appear between 1200 and 1400 local standard time, when the combination of high insolation and temperature leads to enhanced ozone production2.

RESULTS OF A ROCKET EXPERIMENT DESIGNED TO MEASURE DIURNAL VARIATION OF ATMOSPHERIC OZONE

Abstract The rocket-borne ozonesonde, developed by the Atmospheric Sciences Laboratory, White Sands Missile Range (WSMR), N. Mex., has been deployed for the study of diurnal variation of ozone in the stratosphere and mesosphere. Five ozonesondes were rocket launched in January 1968 within a 24-hr period, and the data obtained showed ozone variations between day and night above the main ozone peak (22 km). The ozone concentration in the upper stratosphere increased during the night and decreased during the day. A significant decrease in the ozone concentration was observed after sunrise. A Mast electrochemical ozonesonde was also flown during this 24-hr period to compare the data from the two systems in the region of overlap.

A non-equilibrium investigation into the diurnal photochemical atomic oxygen and ozone variations in the mesosphere

A new investigation has been made into the diurnal photochemical variation of atomic oxygen and ozone in the mesosphere, for an oxygen atmosphere at rest, and for conditions prevailing at the equator. For the first time a diurnal study has been made keeping the equations controlling the atomic oxygen and ozone changes with time in their complete differential form and integrating them simultaneously by the Runge-Kutta method. This approach permits a non-equilibrium study to be made, and one result obtained was that photochemical equilibrium does not exist in the atmosphere above 60 km. The extent of the departure from equilibrium is given and the diurnal variation of the atomic oxygen and ozone is illustrated. The diurnal range of the total ozone amount due to photochemical effects was found to be 0.003 cm S.T.P. The effects of latitudinal and seasonal variations on the results are discussed.

Some observations at Halley Bay in seismology, glaciology and meteorology

1. Seismology Considerable microseismic activity was observed at Halley Bay during the summer season from December to February, particularly during on-shore winds. Examples of microseismic and wind observations are shown to illustrate the nature of the relation between these two observations. The short-period three-component Willmore seismograph used on the floating ice-shelf was found to record P earth waves from earthquakes at most epicentral distances but S waves were badly recorded. 2. Glaciology The results of elevation, temperature and accumulation studies on the ice-shelf are presented and discussed. These indicate that the ice-shelf was floating with its flat upper surface maintained at 28.6 m above sea level by the yearly addition of about 1 m of snow with a mean density of 0.36 g cm -3 . The results of daily accumulation studies are examined ; these show that during winter considerable ablation occurred during 24 h and therefore the net accumulation of longer periods may be due to precipitation greatly in excess of the net accumulation. Geomagnetic survey measurements over a small area around the base showed that the coastal features of the ice-front were defined by geological structure beneath the ice-shelf. 3. Meteorology ( a ) The seasonal features of the behaviour of the atmosphere over Halley Bay up to a height of about 20 km are shown and discussed with special reference to wind and tempera­ture changes. A notable feature is the small annual range of monthly mean air temperatures through the troposphere, where extremes are about 10 °C apart, and the increase in the range of mean air temperatures through the stratosphere culminating, at the top of the ascents, in extremes 59.3 °C apart at the 30 mb surface. ( b ) The variation of total and diffuse solar radiation received at Halley Bay on a horizontal surface is examined for dependence on solar elevation, cloud, and drifting snow. With a solar elevation of between 5 and 35°, total solar radiation is within 5 % of 75 % of the estimated extra-terrestrial radiation in the band from about 0.3 to 3.0 μ. Diffuse radiation accounts for a greater proportion of total radiation as the solar elevation falls from 14 % at 35° elevation to 30% at 5° elevation. The effect of low and medium cloud of all types was found to be similar, and depended on cloud cover and solar elevation. The seasonal and diurnal variation of the net flux of short- and long-wave radiation is examined. Over the year 1958 the net flux of radiation was an outward flow of 590 cal cm -2 , to an estimated accuracy of about 50 %, despite the exceptionally sunny weather of November and December when the mean radiation income amounted to 62 cal cm -2 day -1 . ( c ) The results of sixteen ozone soundings made in 1958 are described and discussed. A clear relation was observed between the first tropopause and the beginning of the ozone layer, even in winter when the determination of the tropopause from temperature lapse changes was more difficult. The results of the soundings describe the seasonal changes in the form of the lower part of the ozone layer and confirm the lateness of the seasonal rise in the total quantity of ozone in the atmosphere as measured by a spectrophotometer. ( d ) The seasonal and diurnal variation of tropospheric ozone, sampled at the surface, is described and discussed. A possible relation between the diurnal movement of the tropo­pause and the amount of surface ozone is examined; no marked relation is found between surface ozone and other meteorological measurements. ( e ) The difference between the two hemispheres in the seasonal change of the total quantity of atmospheric ozone is notable at Halley Bay. Total ozone results from sixteen other I. G. Y. stations are examined to show the seasonal variation of ozone from pole to pole. The relation between fluctuations in the total quantity of ozone and upper-air measure­ments of temperature and pressure is investigated at Halley Bay and south-east England for short (3-day means) and long (10-day running means) periods. At Halley Bay only the short-period fluctuations of total ozone are related to upper-air measurements, but in south-east England both the long- and short-period variations are related.