Application of LDASera Land Surface Models to Drought Monitoring and Prediction

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Application of LDAS-era Land Surface Models to
Drought Monitoring and Prediction

• Andy Wood
• collaborators / contributors
• Shraddhanand Schukla
• Kostas Andreadis
• Dennis Lettenmaier
• Dept. of Civil and Environmental Engineering
• Land Surface Hydrology Research Group
• Drought Monitor Forum
• Portland, OR
• October 2007

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drought definition practices are evolving
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talk outline

• NOAA LDAS research into land surface models
• UW Surface Water Monitor
• forecasting drought
• final comments

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NOAAs Climate Predictions and Projection
ProgramParent Program of CPPA (Climate
Prediction Program for the Americas)

• Objectives
• to provide climate forecasts to enable regional
  and national managers to better plan for the
  impacts of climate variability
• to provide climate assessments and projections
  to support policy decisions with objective and
  accurate climate change information

from j. huang, k. mitchell
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N-LDAS Collaborators
GCIP
North American Land Data Assimilation System
Project
http//ldas.gsfc.nasa.gov
from ken mitchell presentation, march 2002
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LDAS Goals
1) Provide land-state initial conditions (soil
moist, snowpack) for a) realtime coupled model
forecasts of weather / seasonal climate b)
retrospective land-memory predictability
studies 2) Improve LSM physics by sharing
methodologies / data sources 3) Identify causes
of the spread in magnitudes of surface water
fluxes and surface water storage typically seen
in LSM intercomparisons 4) Compare land states
of the uncoupled LDAS with traditional coupled
land/atmosphere 4DDA 5) Demonstrate how to
assimilate land-state related satellite
retrievals (e.g., snowpack, skin temperature,
soil moisture)
from ken mitchell presentation, march 2002
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LDAS Soil Wetness Comparison
LDAS realtime output example
from ken mitchell presentation, march 2002
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most models are in the ballpark on soil moisture
1993
1988
from yun fan / huug vandendool
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models give similar, but different answers
correlations
VIC/Noah are LSMs LB is leaky bucket R/ERA40
are reanalyses
from yun fan / huug vandendool
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NLDAS-era models
snow
1/8-degree resolution Runoff routing,
calibration, validation Vegetation UMD, EROS
IGBP, NESDIS greenness, EOS products Soils
STATSGO, IGBP
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LDAS models
sample validation of historic streamflow simulatio
ns
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What does an 1/8 degree grid cell look like in
real life?
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talk outline

• NOAA LDAS research into land surface models
• UW Surface Water Monitor other efforts
• forecasting drought
• final comments

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SW Monitor in a nutshell

• Background
• merges UW west-wide streamflow forecast system
  methods with NLDAS modeling advances
• index station method VIC implementation
  (Maurer et al., 2002)
• benefits from recent NCDC extension of digital
  data archives back to 1915
• Future Directions
• further development now funded by NOAA TRACS
  program
• test methods for use at NOAA EMC / CPC, with
  products for NWCC NDMC
• water cycle analysis current, retrospective,
  future
• proving ground for forecasting methods at
  national scale
• staging real-time products based on other UW
  drought reconstruction work
• Severity-Area-Duration analysis (Andreadis et al.
  2005)

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Nowcast/Forecast System Consistency Issue
new record or ?
Retrospective Simulation Daily, 1915 to Near
Current
Modern Simulation (last 5 years)
Current Hydrologic State (Nowcast)
ASSIMILATION Snow / Soil Moisture / Runoff /
ETC
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Nowcast/Forecast System Consistency Issue
consistent statistics
Retrospective Simulation Daily, 1915 to Near
Current
Modern Simulation (last 5 years)
Current Hydrologic State (Nowcast)
ASSIMILATION Snow / Soil Moisture / Runoff /
ETC
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www.hydro.washington.edu / forecast / monitor /
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Surface Water Monitor products
1 month change in soil moisture
2 week change in SWE
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Surface Water Monitor archive (1915-current)
June 1934
Aug 1993
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Drought delineation / S.A.D. index
Work of Kostas Andreadis and Liz Clark
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Washington State Monitor
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Monitoring and Prediction Methods
WA State
soil moisture
SWE
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Monitoring and Prediction Methods
WA State
can use model-based systems to estimate traditiona
l drought indices
NOAA PDSI
Oct 8, 2007
work by Shrad Shukla
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WA State testbed for experimental indices
Can we develop alternative, model-based
descriptors of drought and stage them reliably
for use in state local actions?
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talk outline

• NOAA LDAS research into land surface models
• UW Surface Water Monitor
• forecasting drought
• final comments

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drought onset / recovery prediction
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UW weekly national hydrologic predictions
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other nowcast / forecast efforts
Seasonal predictions and verification of Spring
2007 drought conditions from the Princeton U.
VIC/CFS-based uncoupled seasonal forecast
system. (Jan 07 prediction, L. Luo, E. Wood)
http//hydrology.princeton.edu/forecast/
Primary Target
CPCs North American Drought Briefing http//www.c
pc.ncep.noaa.gov/products/Drought/
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talk outline

• NOAA LDAS research into land surface models
• UW Surface Water Monitor
• forecasting drought
• final comments

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Final Comment
LDAS-era models can simulate and will be able to
predict land surface variables (e.g., soil
moisture) as climate forecasts improve. Many
issues need resolving - will there be a
standard or consensus hydrologic product? - a
soil moisture deficit is not the same as
drought - what about traditional /or
meteorological indices?

• How will models (land surface / climate /
  coupled) become integrated into drought
  management?
• nowcasting, forecasting?
• retrospective diagnosis?
• attribution / detection?

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Acknowledgments
NOAA CDEP, CPPA, SARP, TRACS Feedback from Doug
Lecomte (CPC) Kelly Redmond (DRI) Victor Murphy
(SRCC) Mark Svoboda (NDMC) David Sathiaraj
(SRCC/ACIS) Tom Pagano Phil Pasteris (NWCC) In
house Ali Akanda, George Thomas Kostas
Andreadis, Shrad Shukla
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Initial Condition
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Verification possibilities?
What are the obs for drought?
In football, everything is complicated by the
presence of the other team. Jean-Paul Sartre
modeling
observations.
paraphrasing
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SW Monitor Schematic
Index Station Method Gridded Forcing Creation
NOAA ACIS Prcp Tmax Tmin Coop Stations
1955
1930s
VIC Retrospective Simulation Daily, 1915 to Near
Current
VIC Real-time Spinup Simulation
Hydrologic State
Hydrologic State (-1 Day)
Hydrologic values, anoms, -iles
w.r.t. retrospective PDF
climatology (PDF) of hydrologic values w.r.t.
defined period
vals, anoms -iles w.r.t. PDF