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PILPS Update & Proposal
Ann Henderson-Sellers
ANSTO Environment
and Andy Pitman
Macquarie University
Sydney, Australia
ENVIRONMENT
PILPS Update August 2003
• Arctic basin: ACSYS/PILPS
– completed with 17 papers in Special Issue of
Global & Planetary Change (August 2003)
• Tropical forests: PILPS1(c)
– still contributing to publs. (e.g. H-S & Pitman, 2002, BAMS)
• Frozen soil and snow: PILPS 2(d)
– generating publications & prompting questions
• Luo et al. 2003, J Hydromet. (Valdai analysis)
• Coupled PILPS/AMIP II DSP12
– LSS clusters and importance of LSSs in
coupled models now demonstrated
ENVIRONMENT
PILPS - still learning from off-line
• Carbon fluxes: PILPS C1
– going very well; possible introduction to
carbon isotopes
• Arid environments: PILPS San Pedro
– workshop this week (Bastidas & Gupta)
• Isotopes in GLASS: IPILPS
– proposal to be tabled today focuses on:
• Stable water isotopes
• Carbon isotopes
• When do these updates go on the
GLASS web page? ENVIRONMENT
PILPS Update - Highlights
• Chronological sequence in LSSs
– ‘simple’ schemes; SiBlings; current generation
• Classes of carbon parameterisation
– Rapid equilibrium of NPP & early CO2 sinks
– Gradual NPP increase & net CO2 sink zero early
• LSSs behave differently with different GCMs
– Choice of LSS matters to climate prediction
• VIC is a better surrogate for ‘truth’ than re-
analyses for evaporation at least
ENVIRONMENT
PILPS - still learning from off-line
• Chronological sequence in LSSs
– ‘simple’ schemes; SiBlings; current generation
Which group is ‘best’????
ENVIRONMENT
Land-surface Energy Partition
• Energy budgets of 20 models (A-T) & 3 reanalyses
Scatter along
diagonal shows
differences in
partitioning
surface
available
energy
Scatter around
diagonal due to
predictions of
different values
of surface
available energy
Latent Heat Flux W m-2 ENVIRONMENT
LSS Clusters in All Climates
SEBs normalised by ensemble SiBlings
of 3 re-analyses – 3 clusters
Scaled sensible heat W m-2
SiBlings
Buckets
SiBlings
Buckets
Buckets
Scaled latent heat W m-2 SiBlings; latest ENVIRONMENT
Buckets; LSS
PILPS - Off-line Links to GLACE
• Chronological sequence in LSSs
– ‘simple’ schemes; SiBlings; current generation
• LSSs behave differently with different GCMs
– Choice of LSS matters to climate prediction
Coupling does not eliminate characteristics or
impacts of LSSs
ENVIRONMENT
Spatio-temporal Correlation
• Climate trajectories differ for SiBlings &
buckets
• LH improves
Bucket
from Arid
(worst) to E.
Humid (best)
• SH flows the
other way SiBling
SiBling
• Bucket (O) SH
v. small & low Bucket
variability
ENVIRONMENT
Pseudo Land-surface Schemes
• Derived a PLSS for every
Atmospheric forcing from AMIP AGCMs
AMIP II model (A-T): columns
• Apply in 3 basins: Amazon,
Amazon
Mississippi, Mackenzie
• Forced by all AGCMs: rows
} Mississippi
• Find:
– Agreement on main diagonal
• PLSSs do a good job
} – Range for different forcings
• LSSs respond to different AGCMs
– „avg‟ forcing is close to
reported values
Mackenzie • mean = good estmt.
LH ENVIRONMENT
Pseudo Land-surface Schemes
• Ranking predicted LHs
Atmospheric forcing from AMIP AGCMs
Amazon
• Stripes show LSSs
often dominate over
atmospheric forcing
– in three diverse
regimes: Amazon,
Mississippi, Mackenzie
Mississippi
– for 20 different AMIP II
models and land-surface
schemes
Mackenzie Irannejad et al., GRL 2003
Rank ENVIRONMENT
PILPS Update - Highlights
• Chronological sequence in LSSs
– ‘simple’ schemes; SiBlings; current generation
• LSSs behave differently with different GCMs
– Choice of LSS matters to climate prediction
• VIC is a better surrogate for ‘truth’ than re-
analyses
Generally, all known data have been (over)
used for parameterisation – need new!
ENVIRONMENT
VIC Best “Truth” for E/P Ratios
AMIP models
VIC major basins
Obs
BALTEX
VIC closes
water budgets
& best at E/P
Obs
VIC Mississippi
Murray Darling
ENVIRONMENT
Evaluating LSS Performance
SiBlings best
cf. VIC
Intermediate
climates -
reanalyses
and current
LSSs closely
grouped
Irannejad et
al. 2003 find
VIC is best VIC
surrogate for
truth
ENVIRONMENT
Isotopes in PILPS : IPILPS
• Stable and radioactive isotopes are
valuable for both tracing and dating
• Stable water isotope measurements
– Demonstrated that the Amazon recycles
its water (3 or 4 times)
– Prompted early GCM deforestation
experiments (e.g. Henderson-Sellers & Gornitz, 1984)
• Carbon isotopes differentiate C3 and C4
photosynthesis
• Off-line (PILPS) inter-comparison is timely e.g.
– “Heavy” water (HD16O & H218O) at the land surface
– River routing schemes tested against GNIR – the
Global Network for Isotopes in Rivers
Gibson et al., EOS December 2002 ENVIRONMENT
Recycling Small d18O Gradient
1980s
1960s GNIP
Belem
Sao Gabriel Manaus
Porto Velo
Izobamba
Gradient ~ 1.5‰ per 103 km cf. 2.0‰ for Europe
H-S, McGuffie & Zhang,
J. Clim., 2002, 15, 2664 ENVIRONMENT
Basin Isotope Modelling
• Isotopes provide an independent climate and
water resource validation tool
• Weakened signal in central Amazon (Manaus)
indicates increased water recycling
• Logarithmic enhancement in Darling reveals
irrigation impacts
Enhanced
D/H ratio
Darling
Manaus
H-S, Stone, McGuffie etc
GRL, 2003,
ENVIRONMENT
Darling River 2002-3 Drought
d18O and d D
measured in
Brisbane
2002-3 drought
Bourke
Walgett
Wilcannia
Menindie Collarenabri
Burtundy Gunnedah
Sydney
60 Jan 2003
50
40
delta D
Melbourne 30
Jul 2002
20
10
Tracing a non- 0
Jan 2002
1 3 5 7 9 11 13
linear relation delta O-18
ENVIRONMENT
IPILPS: New Data & Results
d18O Belem, Amazon
Belem
dD Precip New isotopic
data from Belem
Vapour
Simulated d18O
Precip
Simulations with ISOLSM ENVIRONMENT
IPILPS Science & Timeline
• QUESTION: Are the stores and fluxes of two
different “heavy” water isotopes (HD16O & H218O)
correctly characterised at the land surface?
• TIMELINE:
– August 2003: Approval by GLASS Panel
– September/October 2003:
• Quality control of the available isotopic & met./hydro. data
– November/December 2003:
• Experimental framework described and agreed
• Water isotopes only or plus carbon isotopes?
– January/February 2004: Call for participation to all
current & past PILPS & AMIP II DSP 12
– April/May 2004: First workshop (possibly in Vienna)
– December 2004: Publication of results ENVIRONMENT
