Studies of columnar observations
and model outputs
Brian Mapes
University of Miami
with thanks to many data producers and sharers
Looking under the hood of
monthly mean data “points”
• Time sections: f(submonthly time x pressure)
– a vast, rich domain
– complementary to typical climate model
examination space (lat x lon x months)
– Natural domain for observations
– Sensible domain for physical processes
Shortcomings
• Free-running climate model time axis not directly
comparable to observations
– statistical comparisons of course
• Models have climate-regime offsets in space, biasing
comparisons at a fixed geo-location
– non-mean statistics that is
• Submonthly variations (dynamics-driven) a poor
proxy for climate sensitivity (thermo-driven)
– tough luck, we do what we can
• Eulerian viewpoint a perverse view of weather
– you’re free to leave
inescapable programming
programming tedium
inescapable
tedium
COARE obs
KWAJEX obs
LBA obs
EPIC, JASMINE
KWAJEX CRM
NCAR CAM
GFDL AM2
NASA GMAO
(super-CAM soon?)
cross-forced SCMs
•SCAM2 driven by CAM
•SCAM driven by AM2
standard raw plots
Common
data format,
variables,
names,
units,
flux sign
conventions,
etc.
standard stat plots
Datasets
All obs are from warm-wet tropics
so far - what I have & know best
COARE obs
KWAJEX obs
LBA obs
EPIC, JASMINE
(more: ARM? etc?)
Cloud obs rare: satellite TOA rad in
~GCM-grid areas, but cloud profiles at
only a few points (cloud radar)
KWAJEX 3D CRM
the most GCM-comparable cloud dataset
NCAR CAM
GFDL AM2
NASA GMAO
(more: CAM-SP?)
Driving the whole exercise -an AMIP, at the very least
cross-forced SCMs
weird experiments,
not done real carefully so far.
Future?
•SCAM2 driven by CAM
•SCAM driven by AM2
What variables?
COARE obs
KWAJEX obs
LBA obs
EPIC, JASMINE
TOA radiation and
cloud forcing
cloud fraction and
condensed water content (p)
KWAJEX CRM
humidity (p)
NCAR CAM
GFDL AM2
NASA GMAO
(super-CAM soon?)
vertical motion (p)
structure
within
troposphere
physical tendencies
heating and drying (p)
cross-forced SCMs
•SCAM2 driven by CAM
•SCAM driven by AM2
CLIMATE
IMPACT
SCALAR
rain
SCALAR
LINK TO
HYD CYC
What plots?
COARE IFA obs
KWAJEX obs
LBA obs
EPIC, JASMINE
KWAJEX CRM
NCAR CAM
GFDL AM2
NASA GMAO
(super-CAM soon?)
cross-forced SCMs
•SCAM2 driven by CAM
•SCAM driven by AM2
IFA OBS
CRF: LW+, SW-, net ~0 [obs needclear-sky assumptions]
note: net <0 at rainiest times
100
RH
cld frac [ crude f(RH) here ]
rain
Q1,
CWC (no obs)
wind divergence and vertical grid
%
0
What stats?
COARE IFA obs
KWAJEX obs
LBA obs
EPIC, JASMINE
Lag regressions I: scalars vs. reference variable
(here, ref = qbudget-derived IFA rain)
TOA rad up:
reflected SW
net
reduced OLR
KWAJEX CRM
NCAR CAM
GFDL AM2
NASA GMAO
(super-CAM soon?)
cross-forced SCMs
•SCAM2 driven by CAM
•SCAM driven by AM2
Other rain vars:
(here, other obs. estimates
models, other rain types)
What stats?
COARE IFA obs
KWAJEX obs
LBA obs
EPIC, JASMINE
KWAJEX CRM
NCAR CAM
GFDL AM2
NASA GMAO
(super-CAM soon?)
cross-forced SCMs
•SCAM2 driven by CAM
•SCAM driven by AM2
regressions vs. IFA rainfall
ocean shading*
~ -20% of latent heat in rain
net
longwave atm heating
~ 15% of latent heating
~6am diurnal rain peak
* straight regression incl. nocturnal zeroes - not really right approach
~1 mm/h x 1d ~24 mm rain
What stats?
II. lag-height regressions of profile
fields vs. surface rain
COARE obs
KWAJEX obs
LBA obs
EPIC, JASMINE
KWAJEX CRM
NCAR CAM
GFDL AM2
NASA GMAO
(super-CAM soon?)
cross-forced SCMs
•SCAM2 driven by CAM
•SCAM driven by AM2
44 km radius
“MCS-resolving”
~1/2 day
timescale
at a point
What stats?
regressions vs. surface rainfall
SYNOPTIC SCALE (IFA)
COARE IFA obs
KWAJEX obs
LBA obs
EPIC, JASMINE
KWAJEX CRM
NCAR CAM
GFDL AM2
NASA GMAO
(super-CAM soon?)
multiscale (incl. several-day timescales)
cross-forced SCMs
•SCAM2 driven by CAM
•SCAM driven by AM2
but no cloud profile observations
TOA: obs
TOA: obs-forcedcondensate
CRM
can’t blow
away
What should
areal cloud
statistics look
like?
KWAJEX
3D CRM
thanks Marat
4-8 units,
vertical
up to 16,
vertical
What stats?
COARE IFA obs
KWAJEX obs
LBA obs
EPIC, JASMINE
KWAJEX CRM
NCAR CAM - IFA
GFDL AM2 - IFA
NASA GMAO
(super-CAM soon?)
cross-forced SCMs
•SCAM2 driven by CAM
•SCAM driven by AM2
regressions vs. surface rainfall - AM2
july - 10 mm/d
TOA about
balanced, long
time scales
layers
upward
development
time jitters
sometimes
zigzag layers
AM2 - a different month
What stats?
COARE IFA obs
KWAJEX obs
LBA obs
EPIC, JASMINE
KWAJEX CRM
nov - 11 mm/d
TOA closely
balanced, long
time scale
slow upward
development
NCAR CAM - IFA
GFDL AM2 - IFA
NASA GMAO
(super-CAM soon?)
cross-forced SCMs
•SCAM2 driven by CAM
•SCAM driven by AM2
zigzag layers
What stats?
COARE IFA obs
KWAJEX obs
LBA obs
EPIC, JASMINE
KWAJEX CRM
NCAR CAM - IFA
GFDL AM2
NASA GMAO
(super-CAM soon?)
cross-forced SCMs
•SCAM2 driven by CAM
•SCAM driven by AM2
regressions vs. surface rainfall - CAM
jan - 7 mm/d
CRF not well
linked to rain
events
3-day waves
vertical thanks
to ‘convective’
fraction but…
…condensed
water not
coherent in
vertical
What stats?
COARE IFA obs
KWAJEX obs
LBA obs
EPIC, JASMINE
KWAJEX CRM
NCAR CAM - IFA
GFDL AM2 - IFA
GMAO 140E/8N July
(super-CAM soon?)
cross-forced SCMs
•SCAM2 driven by CAM
•SCAM driven by AM2
regressions vs. surface rainfall - GMAO
a bit stark but
about like IFA
upward
development,
zigzag layers
2xKwajCRM
ice content
freezing level
schism
rain event met fields - obs
<-KWX
IFA->
rain event met fields - CAM-IFA
<-Jan
Dec->
rain event met fields - 3 models
CAM
AM2
GMAO
But are these brief rain-event
fluctuations a Climate Process?
• hypothesis
Divergence profile in tropical rain events
linked to profile of divergent winds
linked to profile of total winds?
( -> coupling issues…climate by any standard)
? Let’s look
Top- stats of div regression sections (lag-height)
Bottom- stats of total wind speed (time-height)
each curve shows 1 month of data
mean
IFA
AM2
stdev w/in
6-day lag
section
KWAJEX is
3rd line; LBA 4
CAM
All 3 GCMs have
unrealistic
surface-intensified
div fluctuations
GMAOmidlevel
swoop
mean
stdev
GMAO
1000 vs 850
not right
but no near- surface
enhancement of
wind fluctuations
CAMjangly
wind
profiles
wind profile results
• hypothesis too simplistic
• BUT
– Systematic windspeed profile differences from
observations are clear at low levels!
Regressions wrt TOA CRF
“events”?
• Weird idea: submonthly TOA CRF has ~no
feedback to the weather that causes it, so there’s
less expectation of a repeatable “life cycle”
• Proxy for climate sensitivities?
– ? Maybe, if tau << {days, years, decades, etc.} ?
• Anyway, try it (but I have no obs yet)
– use 24h smoothing to kill diurnal cycle
24h-smoothed TOA -CRF as base
time series -- CAM 85W 20S
CRF<0, big slow changes
SWup>0
Whiter w/clouds at 975 not 925
Another month at 85W 20S -- CAM
faster changes, polymodal pdf?
CRF<0
SWup>0
Complicated mixture of events
AM2 - 85W 20S whiteness varies
little; regression structure not stable
steady -30ish CRF
(Q1 data missing)
PBL-based clouds rise to ~550mb here !?
Minghua’s AM2 “midlevel” cloud (ISCCP)
Cross-forced SCMs (CAM <-> AM2)
• V. advection of SCM fields by prescribed
vertical velocity from other GCM
• H. advection prescribed (non-interactive)
• Look at LBA (Amazon) just for fun
LBA obs (via Minghua’s shop), & GCMs
LBA obs
CAM
AM2
(warning: clear sky not careful)
(sorry: Q1 missing)
LBA obs
CAM
AM2
LBA models
AM2
CAM
SCAM driven by AM2
omega
Cloud style
CAMlike
LBA models
AM2
CAM
SCAM2 driven by CAM
omega
Cloud style
AM2 ish
Future plans - team efforts?
standard raw plots
COARE obs
KWAJEX obs
LBA obs
EPIC, JASMINE
KWAJEX CRM
NCAR CAM
GFDL AM2
NASA GMAO
(super-CAM soon?)
Common
data format,
variables,
names,
units,
sign
conventions
standard stat plots
cross-forced SCMs
clickable from Bony
index plot
•SCAM2 driven by CAM
•SCAM driven by AM2
MORE DATA
in (p,t) space
SCMs! CRMs!
EXPERIMENTS!
OBS!
co-ra.com/~bem
more to come
other people