Transcript Measurements and Models of the Atmospheric Ar/N2 ratio

Nature Doesn’t Yield Her Secrets Easily
Mark Battle (Bowdoin College)
Michael Bender (Princeton)
Ralph Keeling (Scripps Institute of
Oceanography)
Pieter Tans (NOAA/CMDL)
Jesse Bastide, Carrie Simonds, Blake Sturtevant,
Becca Perry
EdFest Rochester 8/7/2004
Funding from: NSF, EPA, NOAA GCRP, BP-Amoco, Bowdoin College
Organizing Principle:
1 topic superficially
Organizing Principle:
1 topic superficially
Many topics with vanishing content
My tortuous path
1988-1994: PhD in HEP experiment
1994-1997: Post Doc. at URI-GSO (Oceanography)
1997-1999: Research Scientist at Princeton (Geosciences)
2000 - ? : Asst. Prof. Bowdoin College (Physics)
Where does anthropogenic CO2 end up?
Measurements of O2 and CO2
DO2 = Land biota + Industry
DCO2 = Land biota + Industry + Ocean
Measurements of O2 and CO2
real time collections
The Princeton cooperative flask sampling
network
Ships of opportunity
Automated sample collection systems
O2/N2 changes are small
O2/N2 per meg  (O2/N2sa – O2/N2st)/(O2/N2st) x106
1 per meg = 0.0001%
1 GtC from FF  3.2 per meg O2/N2
1991 – 1997
Land sink = 1.4 ± 0.8 GtC/yr
Ocean sink = 2.0 ± 0.6 GtC/yr
Battle et al. Science 2000 (2467-2470)
Measurements of O2 and CO2
real time collections
average land/ocean
carbon partition
1991 present
Measurements of O2 and CO2
DO2 = Land biota + Industry
DCO2 = Land biota + Industry + Ocean
Measurements of O2 and CO2
DO2 = Land biota + Industry
DCO2 = Land biota + Industry + Ocean
Measurements of O2 and CO2
DO2 = Land biota + Industry
DCO2 = Land biota + Industry + Ocean
Determining the O2:CO2 stoichiometry for the
land biota
Measurements of O2 and CO2
real time collections
average land/ocean
carbon partition
1991 present
measure land
O2:CO2
stoichiometry
air archives
Firn (snowpack) as an air archive
Surface
Firn
Ice
~120m
Influences of firn air composition
•Overlying atmosphere (Fick’s laws)
Influences of firn air composition
•Overlying atmosphere (Fick’s laws)
•Selective exclusion at bubble close-off
(Knudsen regime)
•Gravitational settling (barometric equation)
•Thermal fractionation (kinetic theory)
•Wind pumping/bulk flow (Bernard
convection?)
The forward problem…
1. Posit an atmospheric history
2. Use the history to drive the model forward in time
3. Compare model predictions with observations
The inverse problem…
1. Start with a set of observations
2. What atmospheric history led to those data?
The mechanistic inverse problem…
1. Start with a set of observations
2. What atmospheric history led to those data?
Trial history = a(land sink) +b(fossil source)+g(exclusion flux)
Land sink:
0.4 ± 0.4 GtC/yr
for 1977-1985
Battle et al., Nature 1996
(231-235)
The phenomenological inverse problem…
1. Start with a set of observations
2. What atmospheric history led to those data?
Trial history = f (a,b,g,,t)
Montzka et al., Geophys. Res. Lett., In press
Measurements of O2 and CO2
real time collections
air archives
average land/ocean
carbon partition
1991 present
average land/ocean
carbon partition
19771985
measure land
O2:CO2
stoichiometry
histories of other
species
~1900  present
Full circle…
Bowdoin teaching:
Physics of the Environment (Physics 81): Spring '02, ‘05
Introductory Physics I (Physics 103): Fall, '02
Introductory Physics II (Physics 104): Spring '01, Fall '01
E & M Laboratory (Physics 223L): Fall ‘04
Statistical Mechanics (Physics 229): Spring '00, '01, '02, '03, ‘05
Acoustics (Physics 250): Fall '00
Physical Oceanography (Physics 255): Fall '00, '02
Atmospheric Physics (Physics 256): Fall '01, Fall ‘04
Physics of Particles and Nuclei (Physics 280): Spring '03