Satellite observations of high nighttime ozone at the equatorial mesopause (original) (raw)
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Advances in Space Research, 2007
Long-term measurements of ozone by means of the microwave technique performed at Lindau (51.66°N, 10.13°E), Germany, revealed a winter anomaly of the night-to-day ratio (NDR) which is more clearly pronounced as the so-called tertiary nighttime ozone maximum. The domain of occurrence also differs somewhat from that of the nighttime ozone enhancement. The maximum winter-tosummer ratio amounts to a value of two to three in 70 km height. The annual variation of the NDR is modulated by oscillations of planetary time scale. 3D-calculations on the basis of the advanced GCM LIMA essentially reflect the observations but also show some typical differences which probably result from a somewhat too humid model atmosphere in middle latitudes. We analyzed the most important impacts on the middle mesospheric ozone. The strongest impacts are connected with the annual variation of water vapor and the so-called Doppler-Sonnemann effect considering the influence of the zonal wind on the chemistry due to the fact that ozone is subjected to an effective dissociation longer than molecular oxygen for an increasing solar zenith angle. Because of that the net odd oxygen production decreases faster than the formation of atomic oxygen from ozone which is involved in an odd oxygen destructing catalytic cycle. A shortening of the time of sunset by a west wind regime increases the nighttime ozone level relatively, whereas the daytime ozone is less influenced by the zonal wind in the domain considered.
Journal of Geophysical Research, 2006
1] The Global Ozone Monitoring by Occultation of Stars (GOMOS) instrument on board the European Space Agency's Envisat satellite measures ozone and a few other trace gases using the stellar occultation method. Global coverage, good vertical resolution and the self-calibrating measurement method make GOMOS observations a promising data set for building various climatologies. In this paper we present the nighttime stratospheric ozone distribution measured by GOMOS in 2003. We show monthly latitudinal distributions of the ozone number density and mixing ratio profiles, as well as the seasonal variations of profiles at several latitudes. The stratospheric profiles are compared with the Fortuin-Kelder daytime ozone climatology. Large differences are found in polar areas and they can be shown to be correlated with large increases of NO 2 . In the upper stratosphere, ozone values from GOMOS are systematically larger than in the Fortuin-Kelder climatology, which can be explained by the diurnal variation. In the middle and lower stratosphere, GOMOS finds a few percent less ozone than Fortuin-Kelder. In the equatorial area, at heights of around 15-22 km, GOMOS finds much less ozone than Fortuin-Kelder. For the mesosphere and lower thermosphere, there has previously been no comprehensive nighttime ozone climatology. GOMOS is one of the first new instruments able to contribute to such a climatology. We concentrate on the characterization of the ozone distribution in this region. The monthly latitudinal and seasonal distributions of ozone profiles in this altitude region are shown. The altitude of the mesospheric ozone peak and the semiannual oscillation of the number density are determined. GOMOS is also able to determine the magnitude of the ozone minimum around 80 km. The lowest seasonal mean mixing ratio values are around 0.13 ppm. The faint tertiary ozone peak at 72 km in polar regions during wintertime is observed.
Spatial and Temporal Structure of the Tertiary Ozone Maximum in the Polar Winter Mesosphere
Journal of Geophysical Research: Atmospheres, 2018
Observations from satellites and a ground-based station are combined to construct a global data set for investigating the tertiary ozone maximum in the winter mesosphere for the period August 2004 to June 2017. These give a comprehensive picture of this ozone maximum in latitude, pressure, and time. The location of the tertiary ozone maximum shifts in latitude and pressure with the evolving season; the ozone peak occurs at lower latitude and higher pressure around the winter solstice. Highest average nighttime ozone concentrations and greatest degree of interannual variability are seen in late winter in the Northern Hemisphere (NH). The hemispheric differences and interannual variability in nighttime ozone are related to variations of temperature, H 2 O, and OH associated with dynamical activity. Elevated stratopause events in the NH winter are associated with transport of air that is depleted in H 2 O and enhanced in OH; photochemistry then leads to downward displacement of the altitude of maximum ozone and enhancement in the ozone amount. Transport by planetary waves in the NH extends the region of high ozone further from the pole and leads to longitudinal variations. The analysis shows that while the tertiary ozone maximum responds to a particular radiative situation as shown in previous studies, it is also the result of very dry air found in the winter polar mesosphere.
Mesospheric ozone concentration at an equatorial location from the 1.27-μ m O 2 airglow emission
Journal of Geophysical Research, 1996
The vertical emission profile of the 02 (alAg) airglow at 1.27 •tm has been measured during the evening twilight near the equator (Alcfintara, Brazil; 2.5øS, 44.2øW) using a rocket-borne infrared photometer. The profile is used to derive the vertical distribution of ozone between 60 and 86 km. The ozone profile shows a minimum concentration at 77 km and a secondary maximum of 1.34x 108 cm '3 at 82 km. The height of the secondary maximum is lower than observed at midlatitudes, and the 77-km minimum is sharper than that which has been observed at low latitudes by satellite measurements.
Diurnal and Seasonal Variations of Strato-Mesospheric Ozone
Journal of geomagnetism and geoelectricity, 1996
The J= 61,5-60,6 (110.836 GHz) line of strato-mesopheric ozone has been measured employing a millimeterwave ozone sensor equipped with an SIS mixer receiver. The receiver noise of the SIS mixer is 34 K (SSB), and the spectrometer covers 70 MHz with a frequency resolution of 35 kHz at the present. From these observations, diurnal and seasonal variations of mixing ratio of day and night, and the day/ night ratio of mixing ratio are discussed.
Observation of the diurnal variation of atmospheric ozone
Journal of Geophysical Research, 1982
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. INTRODUCTION AtmoSpheric ozone is important because it absorbs solar ultraviolet radiation, preventing this harmful radiation from reaching the earth's surface. That pollutants originating in the troposphere and diffusing up to the stratosphere may effect irreversible depletion of ozone has prompted efforts toward quantitatively understanding its temporal and spacial behavior. Since the first theoretical postulation of the existence of atmospheric ozone by Chapman [1930], the photochemistry of the stratosphere and mesosphere has been advanced and refined to include numerous complex reactions between ozone and free radicals. Ozone is formed by atomic oxygen recombining with molecular oxygen in the presence of a third body. This occurs in the mesosphere and stratosphere where atomic oxygen is produced by photodissociation of molecular oxgyen in the Schumann-Runge bands and Herzberg continuum, respectively. Destruction of ozone arises partly from its photodissociation by radiation at wavelengths less than 1.08/•m and partly via chemical activity involving oxygen, hydrogen, nitrogen, and chlorine radicals. Photodissociation of ozone by radiation between 198 and 312.5 nm is especially important because it produces metastable atomic oxygen O(•D), which is responsible for the formation of OH and NO, two of the primary radicals that participate in ozone-destroying catalytic cycles. Explanation of the ozone distribution observed in the atmosphere demands that a complex chemical reaction scheme be considered. In the mesosphere there is strong coupling between odd oxygen (O + 03) and odd hydrogen (H + OH + HO2). Inclusion of the latter in the chemical reaction scheme acts to reduce the ozone concentration relative to that predicted by the Chapman mechanism alone. Additional catalytic destruction cycles involving odd nitrogen must be introduced to understand the observed ozone concentrations in the stratosphere.
Spatio-temporal observations of the tertiary ozone maximum
Atmospheric Chemistry and Physics, 2009
We present spatio-temporal distributions of the tertiary ozone maximum (TOM), based on GOMOS (Global Ozone Monitoring by Occultation of Stars) ozone measurements in [2002][2003][2004][2005][2006]. The tertiary ozone maximum is typically observed in the high-latitude winter mesosphere at an altitude of ∼72 km. Although the explanation for this phenomenon has been found recently -low concentrations of odd-hydrogen cause the subsequent decrease in odd-oxygen losses -models have had significant deviations from existing observations until recently. Good coverage of polar night regions by GOMOS data has allowed for the first time to obtain spatial and temporal observational distributions of night-time ozone mixing ratio in the mesosphere.
Study of the seasonal ozone variations at European high latitudes
Advances in Space Research, 2011
The geographic area at high latitudes beyond the polar circle is characterized with long darkness during the winter (polar night) and with a long summertime insolation (polar day). Consequentially, the polar vortex is formed and the surrounding strong polar jet is characterized by a strong potential vorticity gradient representing a horizontal transport barrier. The ozone dynamics of the lower and middle stratosphere is controlled both by chemical destruction processes and transport processes.
An analysis of the annual cycle in upper stratospheric ozone
Journal of Geophysical Research, 1984
The mid-latitude upper stratospheric ozone profiles obtained by the solar backscatter ultraviolet instrument on the Nimbus 7 satellite show a clear annual cycle both in the absolute ozone amounts between 0.98 and 15.6 mbar and in the magnitude of disturbances that reveal themselves as longitudinal structure. At the lowest pressures analyzed a winter maximum in ozone exists, but as one progresses downward in altitude a shift in the temporal phase of the annual cycle occurs in the vicinity of 3 to 4 mbar. Comparison of the observed behavior with the predictions of a one-dimensional photochemical model shows a systematic tendency for calculated ozone amounts to be 20-27% below the data for pressures less than 7.8 mbar. The chemical model successfully predicts the change in phase of the annual cycle, although at a pressure greater than observed. Diagnosis of model results shows the observed shift to be closely coupled to the magnitude of the ozone column density near 3-4 mbar. The wavelengthdependent attenuation of the solar radiation field by ozone alters the relative magnitude of the molecular oxygen and ozone'•lissbciation rates, leading to a change in the temporal phase of the annual cycle. causal mechanisms. DATA HANDLING AND PRESENTATION The ozone data base used in this study was generated by the NASA Ozone Processing Team, using the inversion algorithm described by Schneider et al. ['1981]. This algorithm was applied to the backscattered radiance to solar irradiance ratio• obtained by the SBUV instrument over the period Noverlabe,r 1978 through October 1979. Fleig et al. [1982] present relevant details of the instrument and da,ta processing procedures. The analysis of this paper is confined to three latitude bands, each !0 ø in width, centei'ed on 38ø46'N, 38ø02'S, and the eqt•at9r. The mid-latitude posit!ons were chosen to coincid 9 with the locations of the Lisbon, Portugal, and As-Pendale, Australia, Umkehr sta.tions, although intercomparison of the satellite and ground-based data sets is not performed here. We use ozone data products expressed as column contents integrated between twd pressure surfaces that coincide with the boundaries of'standard Umkehr layers. The laygrs span the. r•nge 0.98-1.95, 1.95oe3.90, 3.90-7.80, and 7.80-Copyright !984 by the American Geophysical Union. Paper number 4D0850.
Observation of near-zero ozone concentrations in the upper troposphere at mid-latitudes
Geophysical Research Letters, 1998
Measurements by an ECC ozonesonde launched from Aberystwyth (52.4øN,-4.1øE) in July show ozone concentrations decreasing steadily from a warm frontal surface to the tropopause, cumulating in a layer-0.5 km deep with near-zero ozone concentrations at 12 km. Such features have previously been detected by lidar but have not been reported in ozonesonde data at mid-latitudes; they have, however, been found in ozonesonde profiles above the equatorial Pacific. We examine three possible hypotheses for the origin of the ozone-free air: in situ destruction by cirrus clouds, rapid transport from the marine boundary layer in the extratropics and long-range transport from the tropics. We conclude that the ozone-poor air observed on this day could only have resulted from long-range transport from the tropics. 1997). In mid-latitudes, an observation of near-zero ozone concentrations was reported by Reichardt et al. (1996) from