Retrieval and characterization of ozone profiles from solar infrared spectra at the Jungfraujoch

in Journal of Geophysical Research-Atmospheres (2002), 107(D24),

[1] Vertical distributions of ozone from June 1996 to November 2000 have been retrieved from high-resolution Fourier transform infrared (FTIR) solar absorption spectra recorded at the primary Network for ... [more ▼]

[1] Vertical distributions of ozone from June 1996 to November 2000 have been retrieved from high-resolution Fourier transform infrared (FTIR) solar absorption spectra recorded at the primary Network for Detection of Stratospheric Change station of the Jungfraujoch in the Swiss Alps (46.5degreesN, 8degreesE, 3580 m above sea level (asl). The retrievals were performed using the Optimal Estimation Method (OEM), both in a narrow spectral interval (1002.567-1003.2 cm(-1)) and in a broad spectral interval (1000.0-1005.0 cm(-1)) in the O-3 9.6-mum band. A thorough characterization of the retrievals has been performed following the lines of OEM, including an information content analysis, a study of the correlations between retrieved instrumental parameters and retrieved ozone concentrations, and an evaluation of the O-3 profile error budget. It is demonstrated that the information content is significantly higher for spectra in the broad microwindow, resulting in higher vertical resolutions, on the order of 8 km, of the retrieved profiles extending up to 40 km, and less correlations between retrieved parameters. An independent statistical verification of the retrieval results and their characterization has been performed by comparison of the FTIR ozone profiles with independent measurements. These are the ozone profile measurements from balloon soundings at Payerne, from the microwave radiometer at Bern and the lidar at Observatoire de Haute-Provence (OHP), and the total column data from the Dobson spectrophotometer at Arosa. Applying the optimum retrieval procedure in the broad spectral interval, an excellent agreement has been found between the FTIR O-3 profile data and the correlative data. The largest offset of the FTIR data in comparison with the correlative data is found with respect to the lidar data in the 24- to 40-km layer, and is on the order of 5%. No systematic biases have been found in the troposphere, neither in the upper troposphere-lower stratosphere (UTLS) up to 18 km. The dispersion of the relative differences between the data sets, if any, is never larger than half of the natural ozone variability. [less ▲]

Monitoring of the variability and long-term evolution of the tropospheric consituents by infrared solar absorption spectrometry at the Jungfraujoch, Switzerland.

Report (2002)

The NOy budget above Jungfraujoch: long-term evolution, family partition and model comparison

in Abstracts presented at the NDSC 2001 Symposium: Celebrating 10 years of atmospheric research (2001)

Based on high-resolution solar spectra recorded with FTIR instruments at the University of Liège laboratory located at the Jungfraujoch NDSC station (Swiss Alps, 46.5ºN, 8ºE, altitude 3580 m), the most ... [more ▼]

Based on high-resolution solar spectra recorded with FTIR instruments at the University of Liège laboratory located at the Jungfraujoch NDSC station (Swiss Alps, 46.5ºN, 8ºE, altitude 3580 m), the most important constituents making up the NOy family have been measured consistently since the mid-1980s. They include HNO3, NO, NO2 and ClONO2, which are analyzed in terms of their vertical column abundances above the site. Related trends have been determined and assessed statistically. Among these, only ClONO2 and NO2 reveal significant long-term trends. The combined column evaluation of NOy indicates a rate of change equal to (0.1+/-0.2) %/year, thus statistically undefined and barely consistent with the evolution of the source gas N2O. Trends derived from the observations will be compared critically with those deduced from a long-term run of a 2-D stratospheric model developed at the University of Oslo. The model includes full gaseous chemistry, PSCs and sulfate particles, which vary from year to year. Comparisons with similar data found in the literature are also discussed. [less ▲]

Free tropospheric CO, C2H6, and HCN above central Europe: Recent measurements from the Jungfraujoch station including the detection of elevated columns during 1998

in Journal of Geophysical Research. Atmospheres (2000), 105(D19), 24235-24249

Time series of free tropospheric carbon monoxide (CO), ethane (C2H6), and hydrogen cyanide (HCN) column abundances have been derived from observations at the International Scientific Station of the ... [more ▼]

Time series of free tropospheric carbon monoxide (CO), ethane (C2H6), and hydrogen cyanide (HCN) column abundances have been derived from observations at the International Scientific Station of the Jungfraujoch (ISSJ) at 3.58-km altitude in the Swiss Alps (latitude 46.55 degreesN, 7.98 degreesE longitude). The free troposphere was assumed to extend from 3.58 to 11 km altitude, and the related columns were derived for all three molecules from high spectral resolution infrared solar spectra recorded between January 1995 and October 1999. The three molecules show distinct seasonal cycles with maxima during winter for CO and C2H6, and during spring for HCN. These seasonal changes are superimposed on interannual variations. The tropospheric columns of all three molecules were elevated during 1998. Increases were most pronounced for HCN with enhanced values throughout the year, up to a factor of 2 in January 1998 when compared to averages of the other years. The increased tropospheric columns coincide with the period of widespread wildfires during the strong El Nino warm phase of 1997-1998. The emission enhancements above ISSJ are less pronounced, and they peaked after the increases measured above Mauna Loa (19.55 degreesN, 155.6 degreesW). Tropospheric trends for CO, C2H6, and HCN of (2.40 +/- 0.49), (0.47 +/- 0.64), and (7.00 +/- 1.61)% yr(-1)(1 sigma) were derived for January 1995 to October 1999. However, if 1998 measurements are excluded from the fit, CO and HCN trends that are not statistically significant, and a statistically significant decrease in the C2H6 tropospheric column, are inferred. Comparisons of the infrared CO columns with CO in situ surface measurements suggest that the CO free tropospheric vertical Volume mixing ratio profile generally decreases with altitude throughout the year. [less ▲]

Protégeons la beauté du ciel nocturne-II

Article for general public (2000)

Not Available

Long-term evolution of the loading of CH4, N2O, CO, CCl2F2, CHClF2 and SF6 above Central Europe during the last 15 years

in J. van Ham (Ed.) Non-CO2 greenhouse gases: scientific understanding, control and implementation (2000)

Long-term monitoring activities of some 20 atmospheric constituents are continuing at the International Scientific Station of the Jungfraujoch, Switzerland, based on remote infra-red solar observations ... [more ▼]

Long-term monitoring activities of some 20 atmospheric constituents are continuing at the International Scientific Station of the Jungfraujoch, Switzerland, based on remote infra-red solar observations with high spectral resolution Fourier transform spectrometers. As a contribution to non-CO2 greenhouse gas investigations, we report the trends observed in the vertical column abundances measured regularly since the mid-1980s for CH4, N2O, CO, CCl2F2, CHClF2 and SF6. With the exception of CO, all species show positive rates of change in their near past atmospheric loading, those of CH4, N2O and CCl2F2 having slowed significantly during the more recent years. The derived rates of change will be compared to findings resulting from ground-level in situ investigations at latitudes similar to that of the Jungfraujoch, and be interpreted in terms of resulting global loading changes. [less ▲]

Vertical column abundances of COF2 above the Jungfraujoch Station: update and consolidation of the database with measurements in the nu4 band region.

in Atmospheric Spectroscopy Applications 1999 (1999)

Spectrometric solar observations at the Jungfraujoch for long-term atmospheric monitoring.

Report (1999)

Recent Characteristic Budjet of Inorganic Chlorine and Fluorine above the Jungfraujoch Station.

in Proceedings of the 4th European Symposium on Polar Stratospheric Ozone 1997. (1998)

Vertical column abundances of COF2 above the Jungfraujoch Station, derived from ground-based infrared solar observations

in Journal of Atmospheric Chemistry (1998), 29(2), 119-134

Total vertical column abundances of carbonyl fluoride (COF2) have been derived from observations made at the International Scientific Station of the Jungfraujoch (ISSJ; altitude 3.58 km, latitude 46.5 ... [more ▼]

Total vertical column abundances of carbonyl fluoride (COF2) have been derived from observations made at the International Scientific Station of the Jungfraujoch (ISSJ; altitude 3.58 km, latitude 46.5 degrees N, longitude 8.0 degrees E), Switzerland. A systematic analysis of two microwindows containing lines of the vi band was performed, based on a large set of high resolution infrared solar absorption spectra recorded with Fourier transform spectrometers, from 1985 to 1995. Examination of the whole available database indicates a significant increase of the burden of COF2 during the 1988-1995 period. The average exponential rate and the average linear rate referenced to 1992, calculated from daily mean measurements, are both equal to (4.0 +/- 0.5)% yr(-1) (one sigma error). The results are also evaluated and discussed within the context of seasonal variability and correlation between carbonyl fluoride and hydrogen fluoride (HF) columns above the ISSJ. [less ▲]