The Codex of Business Writing Software for Real-World Solutions 2.pptx
New Analysis of Old Ship Temperature Data Finds Ocean Warming Signature
1. Can
we
detect
long-‐term,
global
change
from
sparse,
135-‐year-‐old
ocean
data?
Will
Hobbs:
University
of
Tasmania,
IMAS
Josh
Willis
:Caltech/NASA
Jet
Propulsion
Laboratory
2. Ar#st:
John
Steven
Dews
1. Does
the
HMS
Challenger
data
provide
a
reasonable
esNmate
of
global
ocean
temperature?
2. Is
the
esNmated
change
significantly
different
from
natural
variability,
parNcularly
prior
to
IGY?
3. ImplicaNons
for
historical
esNmates
of
sea-‐level
rise
3. SpaNal
sampling
error
Trend
implies
bias
in
ΔT
st.
deviaNon
indicates
random
error
Total
uncertainty=
bias
+
√
(2
x
rand.
error2)
±0.17oC
±0.13oC
4. Sounding
line
error
StaNons
prone
to
bias
are
clustered
in
the
Pacific
Equatorial
Counter
Current,
and
tend
to
show
cooling.
EliminaNon
of
these
staNons
increases
0-‐730m
ΔT
by
0.06oC
(~
17
%)
5. Summary
of
uncertainNes
StaNons
prone
to
bias
are
clustered
in
the
Pacific
Equatorial
Counter
Current,
and
tend
to
show
cooling.
EliminaNon
of
these
staNons
increases
0-‐730m
ΔT
by
0.06oC
(~
17
%)
0-‐730m
(0-‐400
fm)
0-‐1822m
(0-‐1000
fm)
Precision
±
0.014
oC
±
0.014
oC
Sampling
error
±
0.17
oC
±
0.13
oC
Total
±
0.17
oC
±
0.13
oC
Sounding
line
bias
-‐
0.06
oC
?
-‐
0.03
oC
?
6. Significance
of
temperature
change
–
natural
variability
PDFs
are
based
on
1000
random
temperature
differences
for
each
model,
between
Challenger
staNon
sub-‐
sampled
four
year
esNmates
99%
confidence
level
shown
by
red
line
Global
AtlanNc
Pacific
7. Temperature
change
over
Nme
’historical’
simulaNons
show
ΔT
consistent
with
Argo-‐Challenger
esNmates
No
simulated
warming
in
’historicalNat’
experiments
’historical’
–
‘historicalNat’
improves
agreement
between
models,
and
with
obs.
Argo-‐Challenger
Levitus
et
al,2012
9. 3)
Thermosteric
sea
level
rise
0.74
±
0.3
mmyr-‐1
Component
Early
20th
Century
Source
Sub-‐2000m
thermosteric
O(10-‐10
mmyr-‐1)
CMIP5
historical
Glaciers
&
ice
caps
0.59-‐0.68
mmyr-‐1
Gregory
et
al,
2013
(1900-‐1970)
Ice
sheets
-‐
Greenland
-‐0.33
to
0.31mmyr-‐1
Gregory
et
al,
2013
(1900-‐1970)
Terrestrial
storage
-‐0.16
to
-‐0.11
mmyr-‐1
Gregory
et
al,
2013
(1900-‐1970)
Total
0.49
(±
0.3)
mmyr-‐1
Big
pinch
of
salt!
‘Missing’
component
0.25
±
0.4
mmyr-‐1
10. Conclusions
• The
HMS
Challenger
observaNons
provide
a
reasonable
proxy
of
global-‐mean
ocean
temperature,
albeit
with
large
uncertainty
• Even
accounNng
for
this
uncertainty,
the
implied
early
20th
century
warming
is
highly
likely
to
due
to
an
anthropogenic
forcing
• The
Challenger-‐1955
ΔT
esNmate
implies
a
non-‐
thermosteric
contribuNon
of
0.50
±
0.3
mmyr-‐1
for
the
early
20th
century