English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Only very fewlong-term records of formaldehyde (HCHO) existthat are suitable for trend analysis.Furthermore, many uncertainties remain as to its diurnal cycle,representing a large short-term variability superimposed onseasonal and inter-annual variations that should be accountedfor when comparing ground-based observations to, e.g., modelresults. In this study, we derive a multi-decadal time series(January 1988–June 2015) of HCHO total columns fromground-based high-resolution Fourier transform infrared (FTIR)solar spectra recorded at the high-altitude station ofJungfraujoch (Swiss Alps, 46.5° N,8.0° E, 3580 m a. s. l. ), allowing forthe characterization of the mid-latitudinal atmosphere forbackground conditions. First we investigate the HCHO diurnalvariation, peaking around noontime and mainly driven by theintra-day insolation modulation and methane (CH4)oxidation. We also characterize quantitatively the diurnalcycles by adjusting a parametric model to the observations,which links the daytime to the HCHO columns according to themonthly intra-day regimes. It is then employed to scale allthe individual FTIR measurements on a given daytime in orderto remove the effect of the intra-day modulation for improvingthe trend determination and the comparison with HCHO columnssimulated by the state-of-the-artGEOS-Chem v9-02 chemical transport model. Such a parametric model will be useful toscale the Jungfraujoch HCHO columns on satellite overpasstimes in the framework of future calibration/validationefforts of space-borne sensors. GEOS-Chem sensitivity testssuggest then that the seasonal and inter-annual HCHO columnvariations above Jungfraujoch are predominantly led by theatmospheric CH4 oxidation, with a maximum contributionof 25 % from the anthropogenic non-methane volatileorganic compound precursors during wintertime. Finally, trendanalysis of the so-scaled 27-year FTIR time series revealsa long-term evolution of the HCHO columns in the remote troposphereto be related to the atmospheric CH4 fluctuations andthe short-term OH variability: +2.9 % year−1between 1988 and 1995, −3.7 % year−1 over1996–2002 and +0.8 % year−1 from 2003onwards

Diurnal cycle and multi-decadal trend of formaldehyde in the remote atmosphere near 46° N