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Linking the carbon and water cycles through carbonyl sulfide
Róisín
Commane, Harvard University, rcommane@g.harvard.edu
(Presenter)
Ian
Baker, Colorado State University, baker@atmos.colostate.edu
Stephen
A.
Montzka, NOAA, stephen.a.montzka@noaa.gov
Colm
Sweeney, NOAA/ESRL GMD, colm.sweeney@noaa.gov
Debra
Wunch, University of Toronto, dwunch@atmosp.physics.utoronto.ca
Fluxes of carbonyl sulfide (OCS) provide a way to link the carbon and water cycles in the terrestrial biosphere. OCS provides a quantitative, independent measure of biospheric activity, especially stomatal conductance, and allows us to partition photosynthesis and respiration on the ecosystem scale in Arctic and Boreal ecosystems. We can use OCS to better quantify the timing of gross photosynthesis in both spring and fall. It may also help us to quantify changes in photosynthetic uptake over time. In the mid-latitudes, vegetative uptake is the dominant sink of OCS (through hydrolysis by carbonic anhydrase), with a small but significant soil sink (Commane et al., 2015, PNAS). In one conifer forest in Finland, night-time uptake of OCS was almost 30% of the peak daytime uptake, with soil uptake contributing less than 15% of the overall flux (Kooijmans et al., 2017, ACP).
There is a wealth of regional-scale OCS concentration measurements in the ABoVE domain. Regular NOAA vertical profile flights have measured OCS over key locations within the ABoVE domain, including East Trout Lake in northern Canada, the location of TCCON total column OCS (XOCS) measurements since July 2016. The combination of the diurnally resolved TCCON total column XOCS with the NOAA profiles will be a key measure of the regional OCS/CO2 ratio. However, there is limited information about the fluxes of OCS in arctic and boreal ecosystems with which to interpret these regional-scale observations. For example, field measurements from the 1988 ABLE 3A project suggested a small OCS sources from tundra wetlands. Unfortunately, the techniques used in this study were later found to be flawed (Hines and Durham, 1992, JGR).
We can parameterize ecosystem processes based on studies from lower latitudes in a process-based ecosystem model (SiB), but, without on the ground measurements within the ABoVE domain, any interpretation will be subject to large uncertainties.
Associated Project(s):
Poster Location ID: 59
Session Assigned: Carbon Dynamics
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