Interhemispheric comparison of atmospheric circulation features as evaluated from NIMBUS satellite data

Findings are presented for IRIS data from NIMBUS 3 in mapping the global ozone distribution. The seasonal and regional variations of ozone, especially in the Southern Hemisphere, reveal features that were not evident from the sparse ground-based ozone observation network in this hemisphere. A regression analysis was undertaken for temperature and height fields on radiance data. Spectrum analyses of upper wind data from the North American section and Australia were completed

Non-parametric regression analysis of diuron and gabapentin degradation in Lake Constance water by ozonation and their toxicity assessment

Ozone possesses high selectivity in the oxidation of organic pollutants. It actively reacts with electron donating participants which contain π bonds and non-protonated amines groups. The removal efficiency of organic pollutants hugely depends upon the pollutants’ initial concentration and amount of ozone supplied. This study was conducted at Zweckverband Bodensee-Wasserversorgung (Lake Constance Water Supply), Germany. The prime objective of the research was to observe the performance of diuron and gabapentin ozonation for low ozone doses, therefore meeting the real application requirements of the water treatment plant. Thereby, 1 mg·L−1 of the given organic pollutants was chosen for the treatment. The ozone with a dosage of ≈0.68–1.01 mg·L−1 was generated and homogeneously mixed into Lake Constance water in a semi-batch reactor system. The adequate aliquots of diuron/gabapentin were spiked into the homogenous matrix to acquire the desired initial concentration. The effect of ozone dose and reaction time on the degradation of diuron and gabapentin was investigated. Low ozone doses were sufficient for the complete degradation of diuron and gabapentin, although satisfactory total organic carbon (TOC) reduction was not achieved. Nonetheless, the toxicity from ozone treated effluents can be avoided by adjusting treatment conditions. Due to that degradation data obtained did not follow normalization, the non-parametric (non-normalised) data were analysed with a generalised linear regression model for Gaussian and Poisson distribution. Statistical analysis showed that the ozonation treatment of diuron/gabapentin followed the Gaussian model distribution and the degradation data obtained was proven significant using the Kruskal–Wallis test

Harmonisation of the GOME, SCIAMACHY, and GOME-2 total ozone data records for a better understanding of long-term trends and their causes

This thesis addresses the issue of the accurate measurements of ozone distributions in the atmosphere obtained from different satellite borne atmospheric chemistry spectrometers which represent a major need and pre-requisite for determining whether the atmospheric burden of ozone depleting substances (ODS) are reduced in accordance to the Montreal Protocol, and valuable for long-term trend analysis to detect a subsequent ozone recovery. A consolidated and homogeneous long term dataset requires a careful analysis of the relevant parameters used in the retrievals, one important parameter is the absorption cross section. This work presents the procedures followed to correct the ozone cross section data of SCIAMACHY and GOME-2 spectrometers starting from original raw data (optical density spectra). Using the available versions of SCIAMACHY and GOME-2 FM cross sections in the retrieval of total ozone from each satellite leads to an overestimation in the total ozone by 3-5% and 8-9% compared to collocated GOME data, respectively. The quality of the revised temperature-dependent ozone absorption cross sections is investigated over GOME-2 and SCIAMACHY's entire spectral range. The revised data agree well within 3% with other published ozone cross sections and preserve the correct temperature dependence in the Hartley, Huggins, Chappuis and Wulf bands as displayed by the literature data. SCIAMACHY's total ozone columns retrieved using the revised cross section data are shown to be within 1% compared to the ozone amounts retrieved routinely from SCIAMACHY, which uses Bogumil et al. (2003) data but adjusted with a scaling factor of 5.3% and a wavelength shift of 0.08 nm. The total ozone column retrieved from the GOME-2/MetOp-A satellite using the new cross section data is within 1% compared to the ozone amounts retrieved from the standard retrieval performed for GOME-2. The study also presents a long term statistical trend analysis of total ozone datasets obtained from various satellites. A multi-variate linear regression was applied to annual mean zonal mean data using various natural and anthropogenic explanatory variables that represent dynamical and chemical processes which modify global ozone distributions in a changing climate. The study investigated the magnitude and zonal distribution of the different atmospheric chemical and dynamical factors contributing to long-term total ozone changes. The regression model included the Equivalent Effective Stratospheric Chlorine (EESC), the 11 year solar cycle, the Quasi-Biennial Oscillation (QBO), stratospheric aerosol loading describing the effects from major volcanic eruptions, the El Nino/ Southern Oscillation (ENSO), the Arctic and Antarctic Oscillation, and accumulated eddy heat flux (EHF), the latter representing changes due to the Brewer Dobson circulation. The total ozone column dataset used here comprises the SBUV/TOMS/OMI merged data (1979 - 2012) MOD V8.0. The analysis explained most of the ozone variability. The results show that QBO dominates the ozone variability in the tropics (7 DU) while at higher latitudes, the dynamical indices, AO/AAO and eddy heat flux, have substantial influence on total ozone variations by up to 10 DU. ENSO signal are more evident in the Northern Hemisphere. EESC is found to be a main contributor to the long-term ozone decline and the trend changes after the end of 1990s. A positive significant trend in total ozone columns is found after 1997 (between 1 and 8.2DU/decade) which points at the slowing of ozone decline and the onset of ozone recovery. The EESC based trends are compared with the trends obtained from the statistical piecewise linear trend (PWLT or hockey stick) model to examine the differences between both approaches. The results do indicate that the positive PWLT turnaround trends are larger than indicated by the EESC trends, however, they agree within 2-sigma, thus demonstrating the success of the Montreal Protocol phasing out of the ozone depleting substances (ODS). A sensitivity study is carried out by comparing the regression results, using different satellite merged datasets as well as the ground based measurements (1979 - 2012) in the regression analysis in order to investigate the uncertainty in the long-term trends due to different ozone datasets and data versions. All the datasets show almost identical pre-turnaround trends before 1979 for both EESC and PWLT approaches while the positive trends after 1997 are greatly influenced by the short-term variability. In spite of that, all datasets agree within 2-sigma fit parameters

Wintertime losses of ozone in high northern latitudes

Total column ozone data over the past 22 to 30 years from ground-based Dobson and filter ozonometer stations between 30 N and 80 N are analyzed for residual trends remaining after allowance for the known geophysical variations corresponding to: (1) the change of seasons; (2) the quasi-biennial oscillation; and (3) the 11-year solar sunspot cycle. Examination of the data from several ground stations between 45 and 55 N indicated a seasonal difference in the long-term ozone series, with statistically significant losses in several winter months. Accordingly, the data from individual stations were analyzed with multiple regression analysis, seeking trends on a monthly basis after allowance for the known geophysical cycles. Previous statistical analyses were conducted as tests of 1-D model calculations which do not show any differences with the seasons, and any trend toward change in ozone concentrations is expressed in a yearly trend without seasonal variation. Such a model is inappropriate for calculations with a data set which exhibits a pronounced tendency toward seasonal differences in the trends. Comparisons with model calculations then require 2-D models into which seasonal and latitudinal differences can easily be programmed

Epidemiological estimate of growth reduction by ozone in Fagus sylvatica L. and Picea abies karst.: sensitivity analysis and comparison with experimental results

The critical level of ozone flux for forest trees is based entirely on biomass data from fumigation experiments with saplings, mostly in open-top chambers. Extrapolation to mature forests asks, therefore, for validation, which may be performed by epidemiological data analysis. This requires a multivariable regression analysis with a number of covariates to account for potential confounding factors. The present paper analyses the ozone sensitivity of volume increments of mature European beech (Fagus sylvatica) and Norway spruce (Picea abies), with the addition, or removal, of covariates. The comparison of the epidemiological dose-response relationship with experimental data shows very good agreement in beech and a more sensitive relationship in the epidemiological analysis of Norway spruce compared to the experiments. In Norway spruce, there was also a strong interaction between the effects of ozone and temperature; at high July temperatures, the ozone effect was stronger. This interaction may explain the disagreement between the epidemiological study and the experiments, of which the majority were performed in Sweden

Estimating Uncertainty in Long Term Total Ozone Records from Multiple Sources

Total ozone measurements derived from the TOMS and SBUV backscattered solar UV instrument series cover the period from late 1978 to the present. As the SBUV series of instruments comes to an end, we look to the 10 years of data from the AURA Ozone Monitoring Instrument (OMI) and two years of data from the Ozone Mapping Profiler Suite (OMPS) on board the Suomi National Polar-orbiting Partnership satellite to continue the record. When combining these records to construct a single long-term data set for analysis we must estimate the uncertainty in the record resulting from potential biases and drifts in the individual measurement records. In this study we present a Monte Carlo analysis used to estimate uncertainties in the Merged Ozone Dataset (MOD), constructed from the Version 8.6 SBUV2 series of instruments. We extend this analysis to incorporate OMI and OMPS total ozone data into the record and investigate the impact of multiple overlapping measurements on the estimated error. We also present an updated column ozone trend analysis and compare the size of statistical error (error from variability not explained by our linear regression model) to that from instrument uncertainty

Local Effects of Solid Rocket Motor Exhaust on Stratospheric Ozone Concentrations

Solid Rocket Motors (SRMs) power the initial flight of the Space Shuttle and Titan IV rocket. During those first two minutes after liftoff, the exhaust plumes from these motors emit large quantities of chlorine compounds and alumina particles into the atmosphere. For years scientists have argued that such a large chlorine input, injected directly into the stratosphere, would photochemically react with the surrounding air to cause significant ozone depletion. To answer the question of whether SRM exhaust causes a significant ozone depletion, Version 7 data from the Total Ozone Mapping Spectrometer (TOMS) instrument was analyzed for the 30 days prior to a launch to determine any trends and natural ozone variability, and a linear regression analysis was run to calculate a 95% Prediction Interval for the expected ozone range on the day of launch. Of the 23 Overpass data sets and 14 Field of View data sets analyzed, all of the TOMS post-launch total column ozone measurements were found to lie either within or higher than the 95% Prediction Interval range. This analysis indicated no significant reductions in the total column ozone process following a space shuttle or Titan rocket launch, either from Cape Canaveral AFS or Vandenberg AFB

Ozone treatment effects on microbial count on maize

The ultimate goal of this research was to develop a semi-continuous flow grain treatment system and predictive model that will reduce microorganisms on grain kernel surfaces with ozone. The focus of this research was to determine the concentration-time product (CTP) of ozone required to eliminate various levels of microbial growth on grain kernels. To examine the effect of ozone on surface microbes, samples of freshly-harvested and stored maize were treated with ozone for 1 and 3 hours at average ozone concentrations of 1752 ppm, 915 ppm and 37 ppm. Microorganisms were significantly decreased by 28 to 57% after maize samples were ozonated for 1 h at 37 to 1752 ppm and 45 to 80% for 3 h at 37 to 1752 ppm. Linear regression analysis of the CTP data indicated that percent mold reduction increased at a rate of 0.0088 times the CTP. The modified Gompertz equation applied to the microbial inactivation data indicated that a 0.5 to ~1 log mold reduction on maize kernels was attained for ozone concentrations between 37 and 1752 ppm. When compared to preliminary field data from a semi-continuous flow grain treatment system, the laboratory data and the model-predicted values were reasonably close with respect to the microbial load reduction observed on maize samples taken from the system. Keywords: Ozone, Microorganisms, Treatment, Sterilization, Ozone concentration