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Land-surface and the key issues. Bart van den Hurk co-chair GLASS. Overview of key-issues. Model development (parameterization and model structure) Surface characteristics/parameters Land-atmosphere interaction, feedbacks and climate change attribution Data assimilation.

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land surface and the key issues

Land-surface and the key issues

Bart van den Hurk

co-chair GLASS

Land surface key issues and GLASS progress

overview of key issues
Overview of key-issues
  • Model development (parameterization and model structure)
  • Surface characteristics/parameters
  • Land-atmosphere interaction, feedbacks and climate change attribution
  • Data assimilation

Land surface key issues and GLASS progress

general developments in the past decades
General developments in the past decades
  • Increases in
    • number of key components
      • ’80s: surface energy
      • ’90s: surface hydrology
      • ’00s: surface biochemistry
      • ’10s: surface feedbacks (?)
    • spatial detail
      • more surface types become relevant (urban, lakes)
      • more types of land-atm interaction become relevant
    • contribution to predictability at various time scales

Land surface key issues and GLASS progress

outstanding parameterization issues 1
Outstanding parameterization issues (1)
  • Hydrology

P-E > 0

Often it’s not!

We need:

    • groundwater redistribution
    • overland flow (river routing) and wetland formation
    • dynamic calibration procedures
  • Snow

Okavanga river Botswana:

floodplain extent  f(local P)

rms of basin discharge

old scheme

new scheme

snow dominated

basins

Land surface key issues and GLASS progress

outstanding parameterization issues 2
Outstanding parameterization issues (2)
  • Biogeochemistry
    • Photosynthesis and carbon allocation used to be a “climate application”, but…
    • phenology (LAI) and dependence on nutrients and droughts
    • (temperature sensitivity of) soil respiration
    • releases CH4 from wetlands, BVOC from forest, aerosol from arid or urban areas

anomaly fAPAR summer 2003 (obs and modelled); Ciais et al 2005

Land surface key issues and GLASS progress

outstanding parameterization issues 3
Outstanding parameterization issues (3)
  • Human land use and hydrology management
    • urban “tiles”
    • lakes
    • irrigation

Siebert et al, 2005

Land surface key issues and GLASS progress

outstanding issues in land atmosphere interaction
Outstanding issues in land-atmosphere interaction
  • To what extent is land responsible for land-atm.coupling variability?
  • Studies with CRM and LES underway
    • sign of soilm-precip.feedback depends on convective parameterization

PCTL

positive feedback

(Pwet-Pdry)

PCTL

negative feedback

Hohenegger et al, in press

Land surface key issues and GLASS progress

outstanding land data assimilation issues 1
Outstanding Land Data Assimilation issues (1)
  • Multiple systems around (GLDAS, NWP systems) or coming up (Land Flux)
  • Offline systems rely heavily on precip/rad forcing, coupled (“nudging”) systems on assumed dSM/dRH
  • Land Flux from GRP maybe should merge concepts

Science question: will

DA reduce the spread

in current ET estimates?

Land surface key issues and GLASS progress

outstanding land data assimilation issues 2
Outstanding Land Data Assimilation issues (2)
  • Data assimilation is also developing into new observational types
    • (SMOS) soil moisture
    • LAI from NDVI (requires long assimilation window)
  • Data assimilation and parameter estimation become increasingly intertwined
    • parameterization is increasingly relying on calibration rather than model structure
  • The suite of systems requires a coordinated Land Data Assimilation Intercomparison Project (LDAIP)

Land surface key issues and GLASS progress

outstanding feedback attribution issues 1
Outstanding feedback/ attribution issues (1)
  • Diagnostics for land atmosphere coupling vary widely
    • (Koster’s , P/sm, LCL/sm, diurnal T/RH)
  • …but refer to different processes
  • …and are not always observable
  • Integrated framework is being developed in GLASS

Land surface key issues and GLASS progress

outstanding feedback attribution issues 2
Outstanding feedback/ attribution issues (2)
  • Experiments address land use in climate signal
    • Land use 1870 and 1992 provided to 7 GCMs
  • …but LUCID learns that parameter transfer is far from straightforward
    • GCMs have different tile structures and model philosophies (e.g. yes/no phenology, yes/no prognostic albedo, …)

JJA temp response

of land use change

Land surface key issues and GLASS progress

outstanding application operation issues 1
Outstanding application/ operation issues (1)
  • Surface Tile structure
    • debate on “types of heterogeneity” is not as active anymore, but will increase again when spatial resolution increases (land param. in LES)
    • some land surface types demand complex tiling structure (e.g. floodplains/wetlands with coupling to groundwater)
    • tile structure determines interpretation of land use data to a large extent (see LUCID example)
  • Coupled/offline operation
    • e.g. routing/groundwater need horizontal network
    • data assimilation of LAI needs long time window

Land surface key issues and GLASS progress

outstanding application operation issues 2
Outstanding application/ operation issues (2)
  • Land Information System (LIS)
    • LIS is increasingly suited for complex modelling/data assimilation experiments
      • multiple LSMs coupled to WRF or using offline forcings data
      • data assimilation capabilities
    • but its portability can probably be improved
  • Also ECMWF is integrating offline surface driver into Integrated Forecasting System

Land surface key issues and GLASS progress

conclusions on outstanding issues
Conclusions on outstanding issues
  • Parameterization
    • new components (groundwater, lakes, urban, …)
    • new diagnostics and/or experimental set-up:
  • Data assimilation
    • combination of scheme structures desired
    • trade-off data assimilation/parameter calibration revisited
  • Infrastructure
    • need for flexible LIS-type systems will increase

“What is the true contribution of the land

component to the climate system?”

“Does my land surface model describe this

contribution sufficiently well?”

Land surface key issues and GLASS progress

progress report of glass
Progress report of GLASS

LoCo

GSWP

  • The current structure

Land surface key issues and GLASS progress

some issues concerning glass structure
Some issues concerning GLASS structure
  • PILPS-type studies are still quite active (Urban, Snow, Radiation) but does not answer the question: how good should a model be? What benchmark should be considered?
  • Data-assimilation is not well visible in structure
  • Difference between local and global coupling is artificial

Land surface key issues and GLASS progress

proposal for new structure under discussion
Proposal for new structure (under discussion)

Coordinated

LDAIP

LUCID

land-atmosphere

coupling

model data

fusion

LoCo

metrics

GLACE2

LandFlux

PILPS-Urban

benchmarking

SnowMIP

RAMI4PILPS

PILPS-Carbon 2

current projects

new projects

Land surface key issues and GLASS progress

proposal for new structure under discussion18
Proposal for new structure (under discussion)

LUCID

land-atmosphere

coupling

model data

fusion

LoCo

metrics

GLACE2

PILPS-Urban

benchmarking

SnowMIP

Land surface key issues and GLASS progress

global land atmosphere coupling exp 2 glace2
Global Land Atmosphere Coupling Exp 2: GLACE2
  • Adressing potential seasonal predictability from land surface state
  • Integration into WCRP/TFSP project

{

Land surface key issues and GLASS progress

experiment overview
Experiment overview

Step 1:

Initialize land states

with “observations”, using GSWP approach

Perform ensembles of retrospective seasonal forecasts

Evaluate forecasts against observations

Initialize atmosphere with “observations”, via reanalysis

Prescribed SSTs or the use of a coupled ocean model

Land surface key issues and GLASS progress

experiment overview21
Experiment overview

Step 2:

“Randomize” land

initialization!

Initialize land states

with “observations”, using GSWP approach

Perform ensembles of retrospective seasonal forecasts

Evaluate forecasts against observations

Initialize atmosphere with “observations”, via reanalysis

Prescribed SSTs or the use of a coupled ocean model

Land surface key issues and GLASS progress

experiment overview22
Experiment overview

Step 3:Compare skill; isolate contribution of realistic land initialization.

Forecast skill obtained in identical experiment, except that land is not initialized to realistic values

Forecast skill obtain in experiment using realistic land initialization

Forecast skill due to land initialization

Land surface key issues and GLASS progress

confirmed participant list
Confirmed participant list

Group/Model

# models

Points of Contact

1. NASA/GSFC (USA): GMAO seasonal forecast system (old and new)

2. COLA (USA): COLA GCM, NCAR/CAM GCM

3. Princeton (USA): NCEP GCM

4. IACS (Switzerland): ECHAM GCM

5. KNMI (Netherlands): ECMWF

6. GFDL (USA): GFDL system

7. U. Gothenburg (Sweden): NCAR

8. CCSR/NIES/FRCGC (Japan): CCSR GCM

2

R. Koster, T. Yamada

2

P. Dirmeyer, Z. Guo

E. Wood, L. Luo

1

1

S. Seneviratne, R. Andreas

2

B. van den Hurk, H. Camargo, G. Balsamo

1

T. Gordon

1

J.-H. Jeong

1

T. Yamada

11 models

Land surface key issues and GLASS progress

generation of sst boundary conditions
Generation of SST Boundary Conditions
  • Needed: SST conditions for forecasts that do not include measurements of SSTs during the forecast period.
  • Approach: Determine persistence timescales from observational record (with data exclusion) and reduce initial (measured) SST anomalies with time into the forecast, using those timescales.

Land surface key issues and GLASS progress

slide25

“Persisted” SST boundary conditions have been constructed and are now available online. (T. Yamada)

Land surface key issues and GLASS progress

many groups started simulations
Many groups started simulations

Land surface key issues and GLASS progress

original timeline
Original timeline
  • Summer 2007:
    • Finish identifying interested modeling groups
  • Summer 2007
    • Provide data to participants (meteorological forcing data, atmospheric initialization, SST conditions)
  • Summer/Fall 2008
    • Simulations due
  • Fall/Winter 2008
    • First analyses performed

Land surface key issues and GLASS progress

new timeline
New timeline
  • Summer 2007:
    • Finish identifying interested modeling groups
  • Summer 2007
    • Provide data to participants (meteorological forcing data, atmospheric initialization, SST conditions)
  • Summer/Fall 2008
    • Simulations due
  • Fall/Winter 2008
    • First analyses performed

Spring 2008

Fall/Winter 2008

First

Spring 2009

Land surface key issues and GLASS progress

http gmao gsfc nasa gov research glace 2
http://gmao.gsfc.nasa.gov/research/GLACE-2/

Land surface key issues and GLASS progress

proposal for new structure under discussion30
Proposal for new structure (under discussion)

LUCID

land-atmosphere

coupling

model data

fusion

LoCo

metrics

GLACE2

PILPS-Urban

benchmarking

SnowMIP

Land surface key issues and GLASS progress

land use and climate identification of robust impacts lucid
Land Use and Climate – IDentification of robust impacts (LUCID)
  • Designed to separate land use change and GHG signal
  • Multiple phases (prescribed SST  coupled models)
  • Phase 1:
    • Fixed SSTs
    • 4 ensembles (30 yrs, 5 members)
      • pre-industrial/present-day vegetation
      • pre-industrial/present-day GHG & SST
    • 7 GCMs
    • First results presented during sep 2008 Paris w/s

Land surface key issues and GLASS progress

major outcome
Major outcome
  • Transfer of common landuse maps to model parameters quite variable
    • tiling structure
    • assignment of PFTs
    • parameter treatment (fixed/prognostic albedo, z0)
    • phenology (prescribed/prognostic LAI)
  • Result
    • Response between models not very uniform
    • No reason to suspect significant teleconnection patterns from land use
    • GRL paper (Pitman et al) being drafted

Land surface key issues and GLASS progress

lucid jja lhf
LUCID JJA LHF

Small difference between forest/crop LAI

phenology of LAI

Land surface key issues and GLASS progress

proposal for new structure under discussion34
Proposal for new structure (under discussion)

LUCID

land-atmosphere

coupling

model data

fusion

LoCo

metrics

GLACE2

PILPS-Urban

benchmarking

SnowMIP

Land surface key issues and GLASS progress

slide35
LoCo

Fueling convection

  • Multiple processes
  • Multiple diagnostics being explored
  • Proposal for hierarchy of land-atm coupling maps (see GEWEX News November’08)
  • Proof of concept to be applied to SGP with LIS

PBL cloud

formation

Triggering of

convection

direct PBL

feedback on

surface fluxes

remembering

anomalies

Land surface key issues and GLASS progress

proposal for new structure under discussion36
Proposal for new structure (under discussion)

LUCID

land-atmosphere

coupling

model data

fusion

LoCo

metrics

GLACE2

PILPS-Urban

benchmarking

SnowMIP

Land surface key issues and GLASS progress

pilps urban sue grimmond kcl http geography kcl ac uk micromet modelcomparison
PILPS-Urban (Sue Grimmond, KCL) http://geography.kcl.ac.uk/micromet/ModelComparison
  • Aimed at evaluation of urban models
    • range in structure (simple plane parallel canopies  complex multicomponent canyon models)
  • Big group (22 models!)
  • Initial data-set (Vancouver) released for testing
  • Presently: models are running an anonymous city
    • hierarchy of data releases (characteristics, calibration, validation)

Land surface key issues and GLASS progress

proposal for new structure under discussion38
Proposal for new structure (under discussion)

LUCID

land-atmosphere

coupling

model data

fusion

LoCo

metrics

GLACE2

PILPS-Urban

benchmarking

SnowMIP

Land surface key issues and GLASS progress

snowmip richard essery
SnowMIP (Richard Essery)
  • BAMS overview paper submitted
  • Main results:
    • focus on forest
    • 33 models, 11 countries
    • sites Canada, US, Switzerland
    • results:
      • accumulation and ablation ~ ok
      • albedo ~ ok
      • mass and difference forest/open land vary widely
      • soil temperatures too low

Land surface key issues and GLASS progress

slide40
SWE

accumulation at open sites

Land surface key issues and GLASS progress

soil temperature
Soil Temperature

Land surface key issues and GLASS progress

final remarks
Final remarks
  • Parameterization focuses on new components
  • Systematic benchmarking of both models and data is not well embedded but needs attention
  • Data assimilation will benefit from LDAIC
  • New infrastructure inspired on LIS should combine offline modelling, data fusion and benchmarking
  • GLASS panel will get new membership

Land surface key issues and GLASS progress