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At what spatial and temporal scales do we gain useful information from stable water isotope observations?
Harald Sodemann Geophysical Institute, University of Bergen and Bjerknes Centre for Climate Change, Bergen, Norway
SNOWPACE
With acknowledgements to Yongbiao Weng, Mika Lanzky, Alexandra Touzeau, Lukas Papritz, Alexander Läderach,
Astrid Fremme, Andrew Seidl
CLIVAR-US Water Isotopes and Climate Workshop, Boulder, 1-3 Oct 2019
Revised and evolving concepts
Towards a dynamic view on moisture transport
Luetscher et al., 2015
A weather system perspective
Sodemann and Stohl, 2009Winschall et al., 2014
Antarctica, MAM
Mediterranean HPEs
Moisture life time distributions
Sodemann, 2019, revisedthis work,
this work,
this work,
this work,
this work,
this work,
this work,
this work,
(a) (b)8.5 days 8.5 days
Targeting local water cycles
Papritz and Sodemann, MWR, 2018
Image ©: MODIS on Aqua, NASA Worldview
0-12h 12-24h24-36h
36-48h
48-60h
60-72h
72-84h
CAOSvalbard
CAO
AR
Irminger Sea
Fram Strait
Iceland
Norwegian Basin
Measurement opportunities: going in-situ
Disentangling different processes from measurements and modelling
HD16O
H218O
Sodemann et al., 2008
evaporation
mixing
mixed-phasemicrophysics
precipitationH217O
Deuterium excess
17O excess
below-cloud
post-deposition
transport
Interpretation framework: equilibrium vapour
Aemisegger et al., GRL, 2015
liquid phase
vapour phase
αl→v
Interpretation framework: ! diagramΔδ − Δd
Graf et al., ACP, 2019
Measurements during the IGP campaign as part of SNOWPACE, March 2018
Akureyri
R/V Alliance
BAS Twin Otter
Husavik
Husavik
δ18O in snow and vapour
d-excess in snow and vapour
Isotope measurement platforms and procedures
LaboratoryShip
Reliability and intercalibrationSharing tools and routines
Ultralight Aircraft Icebreaker KV Svalbard
High-resolution precipitaiton sampling
Yongbiao Weng et al., in prep.
Landfalling AR in southern Norway, Dec. 2016
A citizen science campaign with sample return
• Information
• Preparing snow kits
• Sample kit distribution
• Distributing snow kits
• Arranging sample return
• Analysis and interpretation
• Communication
Snapshot sampling and Citizen science snow samplingδD / permil
~ -20 permil / ° longitude
PhD Mika Lanzky
Spatial representativeness
Networks of stable isotope measurement stations
Moisture sources for Bergen during 2013 (10-3 mm day-1)Nov Dec Jan Feb Mar Apr
Num
ber o
f CAO
day
s
0
5
10
15
20
25
b)a) 30
Bergen
Bergen
Reykjavik
Reykjavik
Svalbard
Svalbard
ISLAS: plans for evaporation fieldwork in Ny ÅlesundSpring 2020 (during MOSAiC)
Field-deployable unit for isotopemeasurements during evaporation
PhD Andrew Seidl
aircraft campaign, Longyearbyen, March/April 2021
AWI Polar 5/6
Flight patterns • Lagrangian flight experiments• Survey flights• Cloud profiles• Evaporation (low-level)
1st priority: CAO (Cold-air outbreaks) 2nd priority: ARs (Warm air intrusions)
Day 1
Day 2
Day 3 PhD Aina Johannessen
Isotope-enabled regional models as "gold standard"
COSMOisoMARICONWRF
AROME…
Pfahl et al., 2012
ParameterisationsError compensation
ObservationsRepresentativeness
Better global models due to stable isotopes
THEME ”GLOBAL CLIMATE”
Massflux conservation within CAM5/NorESMNorESM with stable water isotopesStable water isotope coupling across components
BCCR subgroup "Water cycle and water isotopes"
Perspectives on the water cycle are evolving - moisture sources vary with weather systems - the lifetime of precipitation has a highly skewed distribution
Spatial representativeness is a prerequisite for model-observation comparisons.
Information contained at short time scales for precipitaiton
Intercomparison of measurements and sharing of methods is key
Forthcoming campaigns will allow to consider the coupling between the components of the water cycle
Regional and global models constrained by stable isotope observations can act as gold standard and progress into operational reach
Conclusions
FARLAB
Instrumentation, domain, forecasts and planning tools
ISLAS campaign period and domainMarch/April 2021 (ca. 3 weeks)Longyearbyen/Tromso/Bjørnøya
Forecasting and flight planning toolsCOSMO-tagging forecastsAROME tendency diagnosticsAROME-Arctic ensembleFLEXPART airmass tagging forecastsMET.3D Virtual Reality visualisationContacts to Met Norway in Tromø
InstrumentationPicarro L2130-i analyzer for water vapour isotopes (1 Hz) with heated inletCloud ice/water sampling with freeze drying unitPTUCloud probesAerosols?
Additional observationsGround-based vapour measurementsGround-based precipitation samplingShip-based measurements?
Simulations with tracer-enabled limited area model COSMOtag
Evaporation masks for CAO tracers: θSST – θ900 > 4 K
Release windows for tracers
Secondary water cycle representing water picked up by CAO air mass via ocean evaporation Winschall et al. 2014, Sodemann et al. 2009
Papritz and Sodemann, MWR, 2018