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The results of systematic (2003–2017) measurements of the total content and the volume mixing ratio of CO at Novolazarevskaya station with a spectrometer with a resolution of 0.2 cm– 1 are presented. The inverse problem of determining the total CO content, as well as interfering gases (H2O and N2O), was solved using the SFIT4 software package. Data analysis showed that over the measurement period the average total CO content at Novolazarevskaya amounted to (8 ± 2) 1017 molec/cm2, and the average volume mixing ratio amounted to (37 ± 8) ppb. The obtained data are compared with variations in the total content of CO in Arrival-Heights station, with MOPITT satellite data, as well as with surface values of CO concentration at Syova station. The maximum values of CO are observed in September, the minimum — in January–February. For all the considered series, the trends are insignificant, while there are periods of increased CO content (2010). In recent years (2014–2017) there is a tendency towards an increase in the minimum values of CO. For Novolazarevskaya and Arrival-Heights satellite data are characterized by the excess of over ground data, amounting to 19% and 14%, respectively, while there is a seasonal dependence of the deviation with the minimum in December–January. Surface measurements of the total CO content are in fairly good agreement at Novolazarevskaya and Arrival-Heights, and since 2010 the average deviation is 2.4%. The average value of the concentration of CO on Syova 51 ppb is higher than the average volume mixing ratio at Novolazarevskaya. According to the spectral, wavelet and composite analyzes, in all the considered series there are oscillations in the range of 6–45 months with closely coinciding periods and phases.

Tropical water vapour volume mixing ratio (WVMR) data for October 2004–September 2015 obtained from the Microwave Limb Sounder are used to study its long-term variabilities and tendencies in the height region 12.1–0.002 hPa. Above 0.01 hPa, the WVMR shows minimum March–May and September–November (∼0.7–0.8 ppmv) and maximum during June–August. It shows a large interannual variability at 31–64 km. The results from multivariate regression analysis show an increasing trend with maximum value of ∼0.045 ppmv/yr at 1.21–0.41 hPa. It shows a significant negative solar cycle response at mesospheric heights.

Methane (CH4) Volume Mixing Ratio (VMR) at pressure level 925hPa data extracted from Atmospheric Infrared Sounder (AIRS) with spatial resolution of 1°× 1° covering whole of Iraq and surrounding regions (28.5°–38.5°N, 37.5°–49.5°E) have been examined for the period from January 2003 to December 2013. The results show a considerable increasing of CH4 with maximum values at north and north eastern regions during autumn and the early winter, whereas the minimum values appeared at the pristine desert environment at the west and the south-west region during spring months. For more accuracy validation the trend analysis was applied on the retrieved AIRS data at three different stations are Mosul, Baghdad and Basrah. The mean and standard deviation in Mosul, Baghdad and Basrah was (1.8657 ± 0.0198, 1.8536 ± 0.0196, 1.8448 ± 0.0212) ppmv respectively for monthly long term trend analysis. Monthly trend analyses have positive trends (0.0040, 0.0039 and 0.0042) ppmv.y-1 for Mosul, Baghdad and Basrah Consecutively. These results indicate that Satellite observations efficiently present the temporal and spatial variations of the CH4 for the considered study Area.

During the first perijove passage of the Juno mission, the Jovian InfraRed Auroral Mapper (JIRAM) observed a line of closely spaced oval features in Jupiter's southern hemisphere, between 30°S and 45°S. In this work, we focused on the longitudinal region covering the three ovals having higher contrast at 5 μm, i.e., between 120°W and 60°W in System III coordinates. We used the JIRAM's full spectral capability in the range 2.4–3 μm together with a Bayesian data inversion approach to retrieve maps of column densities and altitudes for an NH3 cloud and an N2H4 haze. The deep (under the saturation level) volume mixing ratio and the relative humidity for gaseous ammonia were also retrieved. Our results suggest different vortex activity for the three ovals. Updraft and downdraft together with considerations about the ammonia condensation could explain our maps providing evidences of cyclonic and anticyclonic structures.

The rotational spectrum of propionitrile (ethyl cyanide, C2H5CN) in the two lowest excited vibrational states, v 13 = 1 and v 21 = 1 , was studied in detail. The compiled experimental data set consisted of published line lists, lines measured from published spectra up to 645 GHz, and new measurements at frequencies from 8 to 331 GHz. The two states are subject to considerable mutual interaction but application of a- and b-axis Coriolis coupling model to the measured A-symmetry internal rotation substate transitions was found to be successful. A total of over 1900 transitions were fitted for J values up to 76 and K a up to 24, resulting in determined vibrational separation between the two states Δ E = 6.2070246 ( 14 ) cm−1, and Coriolis coefficients | ζ 13 , 21 a | = 0.378, | ζ 13 , 21 b | = 0.127, in good agreement with quantum chemistry calculations. The new line catalog was used to model ALMA spectra of Titan’s atmosphere from 2016, fitting many weak lines not previously modeled. By including the vibrationally excited lines of C2H5CN and a new partition function, we derive a disk-averaged volume mixing ratio estimate in 2016 of 7.8 ± 0.2 ppb assumed constant above 300 km.

This study assesses antioxidant results as a biodiesel additive as fuels in the diesel engine. Biodiesel usage into diesel engine decreases the dependence on imported petroleum and yields benefits like reduction in global warming and engine exhaust emissions. However, inherent drawbacks like lower CV, higher viscosity, and density while increased SFC and NOx emissions limit the biodiesel application in engines. In this way, the additives in the form of antioxidant play a prominent role to mitigate the drawbacks of biodiesel. This investigation main cause to decrease NOx emissions by useof DPPD additive with biodiesel blends. This study uses three different Diesel, B20, B20DPPD1000 test fuels to be prepared at a different volume mixing ratio. This results reported that increase BTE and reduce BSEC of B20 fuel with DPPD additive as contrasted to other test fuels. Also the vital decrease of NOx and CO emissions but slightly increase HC emissions obtained use of B20 fuel with additive.

The total column-averaged volume mixing ratio of atmospheric carbon dioxide ( $$ {\text{X}}_{{{\text{CO}}_{ 2} }} $$ ) has been retrieved with high spectral resolution solar absorption data obtained from ground-based Fourier transform spectrometer (FTS) measurements at Xichong, a coastal site in the district of Shenzhen in southern China. Based on differential optical absorption spectroscopy (DOAS) theory, the $$ {\text{X}}_{{{\text{CO}}_{ 2} }} $$ was retrieved by finding the best match of observed high spectral resolution solar absorption data and monochromatic radiation transfer model calculations. The averaged $$ {\text{X}}_{{{\text{CO}}_{ 2} }} $$ in the whole observation period was about 394.9 ppm. The uncertainty of the retrieval was estimated to be 2.0 ppm (0.51 %) by comparing retrievals at two bands. The preliminary results show that $$ {\text{X}}_{{{\text{CO}}_{ 2} }} $$ retrieved by this method can be used to validate satellite remote sensing of $$ {\text{X}}_{{{\text{CO}}_{ 2} }} .$$

With inadequate information from sensors onboard the SCISAT satellite to generate accurate pointing information, tangent heights for the solar occultation measurements collected by the Atmospheric Chemistry Experiment Fourier transform spectrometer (ACE-FTS) are determined from features in the measured spectra. For version 4.0 processing of the ACE-FTS data, tangent heights below 18 km are generated from the N2 collision induced absorption continuum near 2500 cm−1. Because this tangent height determination requires no assumptions on CO2 concentrations in this altitude region (unlike previous processing versions), ACE-FTS version 4.0 includes retrieved CO2 volume mixing ratio profiles below 18 km as a standard product.

Long lived halogen-containing compounds are important atmospheric constituents since they can act both as a source of chlorine radicals, which go on to catalyse ozone loss, and as powerful greenhouse gases. The long-term impact of these species on the ozone layer is dependent on their stratospheric lifetimes. Using observations from the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) we present calculations of the stratospheric lifetimes of CFC-12, CCl4, CH4, CH3Cl and N2O. The lifetimes were calculated using the slope of the tracer–tracer correlation of these species with CFC-11 at the tropopause. The correlation slopes were corrected for the changing atmospheric concentrations of each species based on age of air and CFC-11 measurements from samples taken aboard the Geophysica aircraft – along with the effective linear trend of the volume mixing ratio (VMR) from tropical ground based AGAGE (Advanced Global Atmospheric Gases Experiment) sites. Stratospheric lifetimes were calculated using a CFC-11 lifetime of 45 yr. These calculations produced values of 113 + (−) 26 (18) yr (CFC-12), 35 + (−) 11 (7) yr (CCl4), 69 + (−) 65 (23) yr (CH3Cl), 123 + (−) 53 (28) yr (N2O) and 195 + (−) 75 (42) yr (CH4). The errors on these values are the weighted 1σ non-systematic errors. Systematic errors were estimated by recalculating lifetimes using VMRs which had been modified to reflect differences between ACE-FTS retrieved VMRs and those from other instruments. The results of these calculations, including systematic errors, were as follows: 113 + (−) 32 (20) for CFC-12, 123 + (−) 83 (35) for N2O, 195 + (−) 139 (57) for CH4, 35 + (−) 14 (8) for CCl4 and 69 + (−) 2119 (34) yr for CH3Cl. For CH3Cl & CH4 this represents the first calculation of the stratospheric lifetime using data from a space based instrument.

There is an unusual decrease of semi-diurnal tidal amplitude in zonal wind at 88 km over Tirunelveli (8.7°N, 77.8°E) prior to the onset of a minor warming event of 2011. During that time, there is a sudden decrease of TIMED-SABER observed ozone volume mixing ratio (VMR) at equator and 60°N. It is suggested that the enhanced planetary wave activity prior to the occurrence of SSW increases the strength of the Brewer–Dobson circulation, which transports stratospheric ozone, the solar insolation absorption of which mainly generates semi-diurnal tide, to high-latitude lower stratosphere and as expected, ozone VMR at 70°N increases in the lower stratosphere.

Column-averaged volume mixing ratios of carbon dioxide (XCO2) during the period from January 2007 to May 2008 over Tsukuba, Japan, were derived using CO2 concentrations measured by Continuous CO2 Measuring Equipment (CME). The CMEs were installed on Japan Airlines Corporation (JAL) commercial airliners, which frequently fly to and from Narita Airport. It was assumed that CO2 profiles over Tsukuba and Narita are the same. CO2 profile data for 493 flights on clear-sky days were analyzed in order to calculate XCO2 with one of two ancillary datasets: "Tsukuba observational" data (rawinsonde and meteorological tower), or "global" forecast/reanalysis and climatological data (NCEP and CIRA-86). The amplitude of the seasonal variation of XCO2 using the ancillary data measured in Tsukuba (XCO2 (Tsukuba observational)) was determined by a least squares fit using a harmonic function to roughly evaluate the seasonal variation over Tsukuba. The highest and lowest values of the obtained fitted curve in 2007 for XCO2 (Tsukuba observational) were 386.4 ± 1.0 and 381.7 ± 1.0 ppm in May and September, respectively, where the errors represent 1 standard deviation of the fit residuals. The dependence of XCO2 on the type of ancillary dataset was evaluated. The average difference between XCO2 from global climatological data, XCO2 (global), and XCO2 (Tsukuba observational), i.e., the bias of XCO2 (global) based on XCO2 (Tsukuba observational), was found to be −0.621 ppm with a standard deviation of 0.682 ppm. The uncertainty of XCO2 (global) based on XCO2 (Tsukuba observational) was estimated to be 0.922 ppm. This small uncertainty relative to the GOSAT precision suggests that calculating XCO2 using data from airliners and global climatological data can be applied to the validation of GOSAT products for XCO2 over airports worldwide.

We report the first results of ground-based millimeter-wave measurements of 183 GHz atmospheric water vapor spectra from Atacama highland (4800 m alt.), Chile. The measurements were carried out in December 2005 by using a spectroscopic radiometer equipped with a superconductive heterodyne receiver. A conspicuous H 2 O spectrum at 183 GHz was detected with an integration time of only 1.5 min, and this is the first high frequency-resolution H 2 O spectrum at 183 GHz obtained in the southern subtropical region. The vertical profile of H 2 O volume mixing ratio between 40 and 64 km were retrieved from the spectrum by using the modified optimal estimation method.

A LEO-ground infrared laser occultation (LGIO) technique is proposed to retrieve the greenhouse gas (GHG) profiles at a specific location, which is practical for monitoring regional weather and climate changes. The harmony search (HS) algorithm with ensemble consideration is applied to retrieve the volume mixing ratio (VMR) profiles of three major GHGs (CO 2 , CH 4 and N 2 O) and H 2 O. The vertical resolution is 1 km below 20 km. The error of VMR with this method is below 10, 5, 5 and 3 % for H 2 O, CH 4 , N 2 O and CO 2 , respectively, at the altitudes from ground to 45 km.

Ozone volume mixing ratio (VMR) profiles are measured by the Michelson Interferometer for passive atmospheric sounding (MIPAS) on ENVISAT. The data sets produced by the science data processor at Institut fur Meteorologic und Klimaforschung (IMK), Germany are compared with those obtained by halogen occultation experiment (HALOE) on UARS and by sub-millimetre radiometer (SMR) on ODIN. For the stratospheric measurements taken during September/October 2002, the three instruments show reasonable agreement, with global mean differences within 0.1-0.3 ppmv. The typical zonal mean differences are of 0.4 ppmv for HALOE and 0.6 ppmv for SMR (4-6%) in the ozone VMR peak region at 25-30 km near the equator, though larger differences of 0.8-1 ppmv (8-10%) are also observed in a small latitude-altitude region in the tropic. A positive bias of about 0.2-0.4 ppmv in the MIPAS data in the 35-40 km region has also been found. Further studies are under way to explain these differences.

In this paper we describe a retrieval approach for the simultaneous determination of the altitude distributions of p, T and VMR of atmospheric constituents from limb-scanning measurements of the atmosphere. This analysis method, named multi-target retrieval (NITR), has been designed and implemented in a computer code aimed at the analysis of MIPAS-ENVISAT observations; however, the concepts implemented in MTR have a general validity and can be extended to the analysis of all type of limb-scanning observations. In order to assess performance and advantages of the proposed approach, NITR has been compared with the sequential analysis system implemented by ESA as the level-2 processor for MIPAS measurements. The comparison has been performed on a common set of target species and spectral intervals. The performed tests have shown that NITR produces results of better quality than a sequential retrieval. However, he simultaneous retrieval of p, T and water VMR has not lead to satisfactory results below the tropopause, because of the high correlation occurring between p and water VMR in the troposphere. We have shown that this problem can be fixed extending the NITR analysis to at least one further target whose spectral features decouple the retrieval of pressure and water VMR. Ozone was found to be a suitable target for this purpose. The advantages of the NITR analysis system in terms of systematic errors have also been discussed. (C) 2003 Elsevier Ltd. All rights reserved.

The increased application of volatility analysis to determine the composition and structure of sub-micron aerosol requires that the thermal behaviour of chemically complex aerosol be understood. Presented here is a volatility study, utilising a tandem volatility differential mobility analyser (TVDMA), of 30, 50, and 70 nm radii, internally mixed, aerosol containing ionic-salts, acids, organics, and carbon. Evidence of some size-dependent behaviour was observed with several of the single component aerosol. Internally mixed aerosol displayed complex thermal behaviours that were dependent on both size and the volume mixing ratio of source solutions.

Research and characterizing the ozone profiles and Ozone Depleting Substances (ODS) in Indonesia is a satellite data-based research activities. The aim of the study was to obtain the characteristics of ozone in Indonesia as well as the contribution of ODS to the variability of ozone. By performing a data inventory based on satellite data, analyze the pattern of annual, seasonal and perform linkage analysis of the contribution of ODS changes to the conditions of ozone. Daily data of vertical profiles of ozone and in the form of volume mixing ratio (vmr) with format HDF (Hierarchical Data Format) is extracted to the territory of Indonesia to take parameters as latitude, longitude, and concentration. Then converted to Excel format with the help of data processing software of MATLAB. Results obtained in the form of ozone characteristics in Indonesia, the percentage of contribution to the variability of ozone also contribution to the variability of ozone in Indonesia in several levels of height. By using Microwave Limb Sounders (MLS) AURA satellite data in the period of 2005 to 2013 characteristics of monthly vertical profiles of ozone in Indonesia has been obtained. The ODS studied were ClO and BrO. Peak of vertical profiles of ozone occurs at a pressure of 10 hPa or altitude of 25.9 km. ClO peak occurs at a pressure of 2.1 hPa or altitude of 30.6 km and BrO reached the peak at 14 hPa or altitude of 24.5 km. When ClO and BrO reach a maximum concentration at stratosphere then ozone molecules is potentially damaging or decrease in the stratosphere. Temporal variations of ozone showed decrease when ODS concentrations increased (particularly ClO and BrO). Linear regression of ozone with ozone showed a negative correlation coefficient which indicates there is a strong relationship between ozone concentrations decline in pressure of 14 hPa when BrO reach the maximum. Likewise for ClO which also showed a negative correlation with the decrease in ozone concentration. ClO contribution to the decreasing of ozone in Indonesia was marked by every addition of 0.01 ppb ClO will reduce ozone of 0.00583 ppm (5.83 ppb). While any increase of 0.01 ppb of BrO will decrease 0.03 ppb of ozone.

We reexamine the “stratospheric fountain” hypothesis by comparing estimates of the annually and zonally averaged volume mixing ratio (vmr) of water vapor entering the stratosphere to annually and zonally averaged estimates of the saturation vmr of the tropical tropopause-region. We find that the vmr of water vapor entering the stratosphere (3.8±0.3 ppmv) agrees well with the saturation vmr of the tropical tropopause-region (4.0±0.8 ppmv). Consequently, our analysis provides no support for the “stratospheric fountain” hypothesis, which required troposphere-to-stratosphere transport to occur preferentially in regions where the tropical tropopause is colder than average.

We have used a one-dimensional photochemical model to investigate the potential role of OBrO in stratospheric photochemistry. The OBrO lifetime against photolysis is likely to be very short (around a few s) which prevents any appreciable concentration during sunlit hours. This rapid photolysis also prevents the gas-phase production of significant OBrO in the model during twilight, as possible precursors (e.g. BrO) are converted to their nighttime reservoirs. Using a range of possible gas-phase production reactions, the maximum (nighttime) OBrO volume mixing ratio produced in the model in the lower stratosphere is around 0.01 × 10−12 (0.01 pptv). These model results contradict recent tentative nighttime balloon observations of large OBrO [Renard et al., 1997, 1998]. We have used our model results to put constraints on the rates of gas-phase and heterogeneous reactions that would be necessary to produce appreciable amounts of OBrO in the stratosphere. These constraints show that if OBrO is indeed present in the nighttime stratosphere at the pptv level, our current understanding of atmospheric bromine chemistry is severely flawed.

Spectroscopic observations of Jupiter at thermal–infrared wavelengths were performed on November 8–9 and December 14, 1994, 16 and 21 weeks after the fragments of comet Shoemaker–Levy 9 collided with Jupiter. Residual stratospheric ammonia was searched for in emission at 930.76 cm−1over the longitudes corresponding to the remnants of the D/G/R/S impact sites. We believe a small amount of ammonia may have been detected in November, but report an upper limit for both dates. The constant volume mixing ratio for pressure levels less than 10 mbar that best fits the observation on November 8 is no more than 3.6 ± 2.4 × 10−10. This upper limit decreased to ≤2.3 ± 3.0 × 10−10on December 14. These values are equivalent to upper limits of 1.9 ± 1.2 × 10−10on November 8 and ≤1.2 ± 1.5 × 10−10on December 14 if we adopt a constant volume mixing ratio above a base at 100 mbar. We also searched, without success, for stratospheric ammonia on November 9 over the K/W and L impact site remnants. Our upper limits place stronger constraints on the stratospheric ammonia lifetimes and photochemical depletion models.

The GRILLE infrared spectrometer was part of the shuttle pay load during the first ATLAS mission in March-April 1992. This experiment measured the vertical distribution of several important minor constituents in the middle to high atmosphere by solar occultation mid-infrared absorption spectroscopy. Among the molecules observed is the stratospheric chlorine reservoir species HCl. This paper discusses the vertical profiles measured, including their validation with respect to correlative measurements from ATMOS on board the same mission and from HALOE on board UARS. The most important conclusion drawn from the measured HCl volume mixing ratio of (3.6±0.2) ppbv above 50 km presently measured by GRILLE in comparison with published ATMOS data from 1985 is that the actual GRILLE data confirm the increase of the upper stratospheric total chlorine loading by about 40% with respect to 1985, as reported and/or predicted earlier.

Vertical distributions of ClO, HCl, N 2 O, and O 3 have been retrieved from airborne observations of pressure-broadened emission spectra in the frequency range of 620 to 690 GHz. Observations were made in February 1994 in the Arctic stratosphere above northern Europe with the Airborne Submillimeter SIS Radiometer (ASUR) during the Second European Stratospheric Arctic and Mid-latitude Experiment (SESAME) 1 campaign. ASUR is the first airborne submillimeter experiment to employ the new superconductor-insulator-superconductor (SIS) receiver technology for stratospheric ozone research. Owing to meteorological conditions, all observations were made outside the polar vortex. The retrieved volume mixing ratio (VMR) profiles show a good agreement with observations made by the submillimeter limb sounder (SLS) operated by the Jet Propulsion Laboratory (JPL) (Pasadena) and the Kern Forschungs Anlage (KFA) (Julich). A comparison between retrieved VMR profiles and profiles obtained from the SLIMCAT three-dimensional stratospheric chemistry model also shows a good agreement. Two ClO emission lines, at 649 and 686 GHz, respectively, are shown to be equally adequate lines for observation purposes. An anticorrelation has been found between the N 2 O and HCl VMR values, and also between the N 2 O and ClO VMR values. The correlations between N 2 O and HCl do not show the relatively low HCl VMR values correlated to relatively low N 2 O values as shown by Webster et al. [1994].

We compare volume mixing ratio profiles of N2O, CFC-11, CFC-12, CCl4, SF6, and HCl in the mid-latitude lower stratosphere measured by the ATMOS Fourier transform spectrometer on the ATLAS-3 Space Shuttle Mission with in situ measurements acquired from the NASA ER-2 aircraft during Nov. 1994. Good agreement is found between ATMOS and in situ correlations of [CFC-11], [CFC-12], and [SF6] with [N2O]. ATMOS measurements of [CCl4] are 15% high compared to ER-2 data, but agree within the systematic uncertainties. ATMOS observations of [HCl] vs [N2O] are within approximately 10% of ER-2 data for [HCl] > 1 ppbv, but exceed in situ measurements by larger fractional amounts for smaller [HCl]. ATMOS measurements of [ClONO2] agree well with values inferred from in situ observations of [ClO], [NO], and [O3]. The sum of [HCl] and [ClONO2] observed by ATMOS, supplemented by a minor contribution from [ClO] estimated with a photochemical model, is consistent with the levels of inorganic chlorine inferred from in situ measurements of chlorine source gases.

We compare volume mixing ratio profiles of N2O, O3, NO(y) H2O, CH4, and CO in the mid-latitude lower stratosphere measured by the ATMOS Fourier transform spectrometer on the ATLAS-3 Space Shuttle Mission with in situ measurements acquired from the NASA ER-2 aircraft during Nov 1994. ATMOS and ER-2 observations of [N2O] show good agreement, as do measured correlations of [O3], [NO(y)], [H2O], and [CH4] with [N2O]. Thus a consistent measure of the hydrogen (H2O, CH4) content of the lower stratosphere is provided by the two platforms. The similarity of [NO(y)] determined by detection of individual species by ATMOS and the total [NO(y)] measurement on the ER-2 provides strong corroboration for the accuracy of both techniques. A 25% discrepancy in lower stratospheric [CO] observed by ATMOS and the ER-2 remains unexplained. Otherwise, the agreement for measurements of long-lived tracers demonstrates the ability to combine ATMOS data with in situ observations for quantifying atmospheric transport.

The relationship between surface-level observations of daily maxima in ozone (O 3max ) volume mixing ratio and ambient air temperature (Tmax) has been studied at an urban site, i.e. Pune (18.4°N, 73.8°E), India during 2003-04. The mixing ratios of O 3max were found to be highest during winter to pre-monsoon period and lowest in the monsoon season. The dependence of O 3max levels on T max has been quantified using the linear regression fit for the different seasons. However, except for the monsoon season, reasonably good correlations between O 3max and T max were noticed. The correlation between daily O 3max concentration and minimum NO x (NO x min ) concentration was also studied to assess the importance of photochemical mechanism mainly reduction in the loss due to titration. Overall, the strong dependencies of O 3max on Tmax and NO x min signify the role of both meteorological and photochemical processes during most months of a year. The positive slopes of ΔO 3max /ΔT max and ΔO 3max /ΔNO xmin clearly indicate the role of significant production and accumulation of O 3 under high temperature and low NO x conditions respectively, during winter and premonsoon seasons. The statistical analysis of O 3 in relation with the key meteorological and chemical parameters is important to understand the sensitivity of secondary pollutants on various controlling factors.

[1] A correlative study of rotational temperatures and radiance of mesospheric hydroxyl (OH) was made using spectrographic measurements from the midlatitude site at Millstone Hill, Massachusetts (42.6°N, 71.5°W). The OH radiance and temperatures were strongly correlated, and the correlation showed a marked seasonal dependence. The dependence was also evident on smaller timescales ranging from days to months. Dynamical effects appeared to dominate the temperature-radiance relationship compared to the photochemistry responsible for the hydroxyl emission rate. The effect was illustrated clearly when the measurements were temporally averaged, hence removing the dynamical influence. A strong summer maximum in OH radiance was observed contrary to a minimum in summer Mass Spectrometer Incoherent Scatter (MSIS) [O] volume mixing ratio values. An increase in mesospheric gravity wave activity during the summer, a feature not observed by the MSIS model, was the likely cause of the summer OH maximum.

[1] This study examines the effect of a sudden stratospheric warming (SSW) on the thermosphere, and in particular the response of thermospheric O(1S) dayglow as a proxy for SSW-induced variations in the atomic oxygen volume mixing ratio. Thermospheric O(1S) volume emission rates and temperatures observed by the WIND Imaging Interferometer on UARS in February 1993 at latitudes from 50°N to 70°N and from 90 km to 280 km height have shown a depletion above 140 km in the daytime O(1S) volume emission rates, which commenced around the onset of the SSW and lasted over a period of 3–4 days before returning to and exceeding the pre-SSW values during the SSW recovery phase. Below 140 km height the effect was manifested by a fourfold enhancement in the O(1S) volume emission rate at ∼100 km, which correlated with the cold temperature anomaly of the SSW at and below the stratopause.

Ammonia plays an important role in many biogeochemical processes, yet atmospheric mixing ratios are not well known. Recently, methods have been developed for retrieving NH3 from space-based observations, but they have not been compared to in situ measurements. We have conducted a field campaign combining co-located surface measurements and satellite special observations from the Tropospheric Emission Spectrometer (TES). Our study includes 25 surface monitoring sites spanning 350 km across eastern North Carolina, a region with large seasonal and spatial variability in NH3. From the TES spectra, we retrieve a NH3 representative volume mixing ratio (RVMR), and we restrict our analysis to times when the region of the atmosphere observed by TES is representative of the surface measurement. We find that the TES NH3 RVMR qualitatively captures the seasonal and spatial variability found in eastern North Carolina. Both surface measurements and TES NH3 show a strong correspondence with the number of livestock facilities within 10 km of the observation. Furthermore, we find that TES NH3 RVMR captures the month-to-month variability present in the surface observations. The high correspondence with in situ measurements and vast spatial coverage make TES NH3 RVMR a valuable tool for understanding regional and global NH3 fluxes.

The influence of micromixing on precipitation is predicted qualitatively for batch or semibatch precipitations by means of a simplified mixing model, which considers primary nucleation as the main process affected significantly by hydrodynamics. Unwanted micromixing effects are avoided to a maximum in a batch configuration designed to have a volume mixing ratio α close to unity. Using a semibatch precipitator or a batch with a high α value dramatically accentuates mixing interactions. For mixing, changing the feed point location is shown to have much stronger influence than changing the stirring speed and constitutes an efficient test of micromixing. Experimental evidences for these conclusions have been established for calcium oxalate monohydrate batch precipitation. In particular, the early seconds of the reaction (when mainly primary nucleation occurs) have been demonstrated as conditioning the subsequent behavior of the precipitation, even for induction times of a few minutes.

[1] The first measurements of CFC-113 (CCl2FCClF2) and HCFC-142b (CH3CClF2) from space have been performed by the Atmospheric Chemistry Experiment (ACE), a satellite-based mission for remote sensing of the Earth's atmosphere. Retrievals for the volume mixing ratio profiles of these two molecules have been performed for ACE-FTS measurements at mid-latitudes and in the tropics, and the results are compared with AGAGE surface measurements. The agreement between ACE and AGAGE mixing ratios is within 15% for both CFC-113 and HCFC-142b.

Procedures are described for pressure, temperature, and volume mixing ratio retrievals for the Atmospheric Chemistry Experiment, a satellite mission for remote sensing of the Earth’s atmosphere developed under the auspices of the Canadian Space Agency.

An ESA supported study was carried out for the development of an optimized code for near real time retrieval of altitude profiles of pressure, temperature (p, T) and volume mixing ratio (VMR) of five key species (O3, H2O, HNO3,CH4 and N2O) from infrared limb sounding spectra recorded by MIPAS (Michelson Interferometer for Passive Atmospheric Sounding), which will be operated on board ENVISAT-1 satellite.

Balloon-borne infrared sunset solar spectra in the 780 cm−1 region have been used to derive upper limits for the amount of ClONO2 in the stratosphere. These upper limits for the volume mixing ratio are 4 × 10−11 to 2 × 100−9 between 15 and 30 km with an error factor of 2. These values only show that the postulate that ClONO2 is a temporary reservoir for ClO and NO2 cannot be ruled out.

The simultaneous measurement of the 1-0 bands of HCl and HF has been achieved from near-infrared solar absorption spectra obtained during a balloon flight near Fairbanks, Alaska (65°N, 148°W) in the evening of May 22, 1976. Several lines from each band have been measured to provide volume mixing ratio profiles for both constituents from 15 to 30 km. The HCl profile is consistent with the results of other workers, however the HF profile shows a substantially larger concentration than a recent determination.

An overview is given of the positive ion composition measurements performed with balloon-borne ion mass spectrometers in the Earth's atmosphere between 20 and 45 km. In particular, attention is paid to the derivation of the acetonitrile volume mixing ratio profile. The results are compared with model calculations, data obtained with airplane-borne instruments, and ground-level samplings. The consistency of the present picture is verified. The comparison with results of recent laboratory experiments show that electric field-induced collisional dissociation occurs in balloon-borne ion mass spectrometers. Probably, this is one of the major causes for the observed discrepancies between the data of airplane- and balloon-borne instruments.

The vertical profile and total column concentration of HCl have been measured from ground based high resolution infrared absorption spectra. The lines recorded were the R1 and P5 of HCl35 at 2942.731 cm−1 and 2775.760 cm−1 respectively. Vertical profiles and column concentrations are reported for different seasons. Measurements indicate an HCl volume mixing ratio equal to (2.2 ± 0.5) × 10−11 at 10 km increasing to (3.4 ± 0.6) × 10−9 at 33 km.

Middle and upper stratospheric HCN has been measured using ground-based mm-wave emission spectroscopy during a series of observations made in Mauna Kea, HI, in June 1986. A volume mixing ratio of 190 + or - 40 pptv at about 40 km, and a decrease of concentration with altitude that is considerably slower than that predicted by current models are found. This could be an indication of an atmospheric source of HCN as yet unidentified.

In July 1974 an NO/O3 chemiluminescent instrument was used to obtain measurements of NO in the stratosphere during two balloon flights launched from Churchill (59°N, 95°W). On the first flight, an altitude profile was obtained in which the NO volume mixing ratio was observed to increase from 0.3 to 2.7 ppbv between 19 and 29.5 km. On the second flight, the mixing ratio was observed to increase from 0.25 to 2.7 ppbv between 19 and 29 km and to remain almost constant at about 2.7 ppbv from 29 to 34.5 km. On this flight, the sunset decay of NO was also obtained while the payload was at a constant float altitude of 34.5 km. These decay measurements are compared satisfactorily with the results obtained from a time dependent stratospheric model.

Simultaneous measurements of NO and NO 2 in the stratosphere leading to an NO x determination have been performed by means of i.r. absorption spectrometry using the Sun as a source in the 5·2 μm band of NO and in the 6·2 μm band of NO 2 . The observed abundance of NO P peaks at 26 km where it is equal to (4·2 ± 1) × 10 9 cm −3 . The volume mixing ratio of NO p was observed to vary from 1·3 × 10 −9 at 20 km to 1·3 × 10 −8 at 34 km.

Vertical profiles of the CH4 mixing ratio in the troposphere and stratosphere were obtained by collecting air samples and analyzing their CH4 concentrations by gas chromatography. Two sets of tropospheric profiles, each covering a full year, have been measured; one over the Pacific 200 km offshore from Santa Barbara, California, and one over Scottsbluff, Nebraska. Although some of the individual profiles showed large fluctuations with time and space, a systematic seasonal variation of tropospheric CH4 concentration could not be established. On a 1-year average, CH4 has a nearly uniform distribution in the troposphere, with an average volume mixing ratio of 1.41 ppmv. The only systematic gradient in the troposphere was observed for the Scottsbluff profiles which showed a decrease in the CH4 mixing ratio close to the ground. In contrast, the stratospheric CH4 profiles showed a systematic decrease with altitude, with a steeper gradient directly above the tropopause. The gradient appears to be weaker at higher altitudes. At 50 km the CH4 mixing ratio has dropped to 0.25 ppmv.

Infrared emission spectra of the long-wavelength wing of the 6.3 µm water band between 6.7 and 7.6 µm have been measured in the mesosphere using a cryogenic rocketborne spectrometer. The resulting zenith radiance profile has been compared with a high altitude radiance model resulting in a volume mixing ratio of 3.5 ± 2.2 ppm between 49 and 70 km.

From air samplings on aircraft in February and December 1982 and in February 1983, and from gas-chrornatographic measurements, the background volume mixing ratio of sulfur hexafluoride(SF6) over Japan was found to be about (0.72±0.13) ppt, where ppt=10−12. Since the first observation by Lovelock in 1970 (0.03 ppt), SF6 seems to have been increasing steadily.

New observational data are discussed which indicate that: (a) Nitrous oxide is uniformly mixed with the atmosphere up to 10 km and perhaps to 40 km, and that the volume mixing ratio is 3.5 × 10−7. (b) Bacterial reactions in the soil can supply nitrous oxide to the atmosphere at a rate sufficient to compensate photo-chemical decomposition. (c) The formation of nitrous oxide by homogeneous chemical reactions is probably of less importance. (d) The average magnitude of the nitrogen cycle between earth and atmosphere is probably not less than 1011 molecules cm−7 sec−1..

Vertical profiles of the stratospheric CCl4, CH3C1, CH3CC1, C2F2C13 mixing ratios derived from two balloon flights over Southern France (44° N) in 1982 and 1983 are presented. A total of 26 air samples were collected in situ by a newly developed balloon-borne cryogenic sampler. The samples were analysed in the laboratory within four weeks after the flight employing two different analytical techniques: gas chromatography and a gas chromatograph/mass spectrometer combination. The observed mixing ratios are well in the range of previous determinations of these species in the stratosphere. Above about 30 km CC14 and CH3CC13 mixing ratios are below the analytical detection limits of both techniques. A comparison with 1-D model calculations shows that for all species the observations are lower than the theoretical profiles.

Spectral line emission at 183 GHz (1.64-mm wavelength) by upper atmospheric H 2 O was measured on the NASA Convair-990 during the Interhemispheric Survey in October and November 1976. The measurements indicate a water vapor volume mixing ratio of approximately 5 × 10 −6 in the upper stratosphere/lower mesosphere and suggest an increase in upper stratospheric H 2 O from subtropical to subpolar latitudes.

MIPAS thermal limb emission measurements were used to derive vertically resolved profiles of carbon tetrachloride (CCl4). Level-1b data versions MIPAS/5.02 to MIPAS/5.06 were converted into volume mixing ratio profiles using the level-2 processor developed at Karlsruhe Institute of Technology (KIT) Institute of Meteorology and Climate Research (IMK) and Consejo Superior de Investigaciones Científicas (CSIC), Instituto de Astrofísica de Andalucía (IAA). Consideration of peroxyacetyl nitrate (PAN) as an interfering species, which is jointly retrieved, and CO2 line mixing is crucial for reliable retrievals. Parts of the CO2 Q-branch region that overlap with the CCl4 signature were omitted, since large residuals were still found even though line mixing was considered in the forward model. However, the omitted spectral region could be narrowed noticeably when line mixing was accounted for. A new CCl4 spectroscopic data set leads to slightly smaller CCl4 volume mixing ratios. In general, latitude–altitude cross sections show the expected CCl4 features with highest values of around 90 pptv at altitudes at and below the tropical tropopause and values decreasing with altitude and latitude due to stratospheric decomposition. Other patterns, such as subsidence in the polar vortex during winter and early spring, are also visible in the distributions. The decline in CCl4 abundance during the MIPAS Envisat measurement period (July 2002 to April 2012) is clearly reflected in the altitude–latitude cross section of trends estimated from the entire retrieved data set.

Three millimeter-wavelength transitions of ClO were searched for in the stratospheric emission spectrum during May-August 1977 using aircraft-based instruments. The measurements indicate that if stratospheric ClO has a vertical distribution of the form predicted by present photochemical models, then the ClO volume mixing ratio at the profile peak did not exceed 10 to the -9th at the time and place of the measurements. The observed spectra suggest the presence of ClO in the stratosphere but do not provide a definitive detection.