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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.

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.

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.

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.

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.

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.

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.

[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.

[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.

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.

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.

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.

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.

The altitude distribution of nitric oxide was measured during three balloon flights in August 1976 and 1978. Median values of the volume mixing ratio at 18, 24, 30, and 34 km were 0.4, 1.4, 6.5, and 13 ppb, respectively. The data are discussed in relation to an average profile of nitrogen dioxide measured for this season and latitude and in relation to current one-dimensional models of the stratosphere.