Journal articles
Experimental investigation of the stable water isotope distribution in an Alpine lake environment (L-WAIVE)
Abstract : In order to gain understanding on the vertical
structure of atmospheric water vapour above mountain lakes
and to assess its link with the isotopic composition of
the lake water and with small-scale dynamics (i.e. valley
winds, thermal convection above complex terrain), the L-
WAIVE (Lacustrine-Water vApor Isotope inVentory Experi-
ment) field campaign was conducted in the Annecy valley in
the French Alps during 10 d in June 2019. This field cam-
paign was based on an original experimental synergy be-
tween a suite of ground-based, boat-borne, and two ultra-
light aircraft (ULA) measuring platforms implemented to
characterize the thermodynamic and isotopic composition
above and in the lake. A cavity ring-down spectrometer and
an in-cloud liquid water collector were deployed aboard one
of the ULA to characterize the vertical distribution of the
main stable water isotopes (H162 O, H182 O and H2H16O) both
in the air and in shallow cumulus clouds. The temporal evo-
lution of the meteorological structures of the low troposphere
was derived from an airborne Rayleigh–Mie lidar (embarked
on a second ULA), a ground-based Raman lidar, and a wind
lidar. ULA flight patterns were repeated several times per
day to capture the diurnal evolution as well as the variabil-
ity associated with the different weather events encountered
during the field campaign, which influenced the humidity
field, cloud conditions, and slope wind regimes in the valley.
In parallel, throughout the campaign, liquid water samples
of rain, at the air–lake water interface, and at 2 m depth in
the lake were taken. A significant variability of the isotopic
composition was observed along time, depending on weather
conditions, linked to the transition from the valley boundary
layer towards the free troposphere, the valley wind intensity,
and the vertical thermal stability. Thus, significant gradients
of isotopic content have been revealed at the transition to the
free troposphere, at altitudes between 2.5 and 3.5 km. The
influence of the lake on the atmosphere isotopic composition
is difficult to isolate from other contributions, especially in
the presence of thermal instabilities and valley winds. Nev-
ertheless, such an effect appears to be detectable in a layer
of about 300 m thickness above the lake in light wind condi-
tions. We also noted similar isotopic compositions in cloud
drops and rainwater
https://hal-insu.archives-ouvertes.fr/insu-03298935
Contributor : Catherine Cardon Connect in order to contact the contributor
Submitted on : Sunday, July 25, 2021 - 11:19:44 AM
Last modification on : Wednesday, September 15, 2021 - 12:02:04 PM
Contributor : Catherine Cardon Connect in order to contact the contributor
Submitted on : Sunday, July 25, 2021 - 11:19:44 AM
Last modification on : Wednesday, September 15, 2021 - 12:02:04 PM
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acp-21-10911-2021.pdf
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