EOS Semi-Arid Interstorm Model
- Goal: Diagnosis of evapotranspiration
- Components:
- Analyzed large-scale tendencies and BC’s (ETA)
- Regional Atmospheric Modeling System (RAMS)
- Data Assimilation
- Diagnostic, continuous model run
- Near real-time on PC workstation
- Current focus: San Pedro Basin
- Current work:
- Evaluate surface-vegetation atmospheric transfer (SVAT)
schemes for data assimilation
- Assimilate observed shortwave radiation (Poster 2.2)
- http://www.hwr.arizona.edu/IS
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 SiB2c--RAMS
Coupling
- SiB2c replaces standard SVAT of RAMS
- Run over semi-arid region of 220 x 220 km2
- Vegetation Parameterization
- Choose four cover types to represent range of vegetation
types in the model domain
- C4 grassland, conifer, shrub, riparian, and bare soil
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Why SiB2c?
- Sellers, et al. 1996
- Modern canopy photosynthesis-conductance model
- Established relationships between vegetation index and
vegetation parameters
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 Why Use Patchy
Cover?
- Affects surface energy balance and effective radiometeric
temperature
- Evenly distributed canopy unrealistic in this environment
- Remotely sensed products to be assimilated
- Solar radiation
- surface temperature
- Postulate patchy cover
- Each pixel contains a mixture of one of the above vegetation
types and bare soil
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SiB2c Surface Temperatures
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Model Calibration
- Spatially distributed model
- Point observations
- 47 SiB2c parameters
- expect high degree of parameter interaction
- hand calibration / physical arguments lead to success
in case of high temperature inhibition
- select several ‘important’ parameters
- still a very tough problem
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SiB2c High Temperature Inhibition
- Lucky Hills
- Summer 1996 comparison study (Houser et al., this issue)
- Critical temperature for ET cutoff increased from 310
K to 320 K
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Example Output
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Future Work
- Assimilate additional sources of remotely sensed data
- Surface temperature
- adapt SiB2c’s time-varying FPAR
- Evaluate more realistic aggregation algorithms
- Model calibration
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Acknowledgement
Primary funding for this research was provided under the
Sorooshian/Kerr NASA-EOS Interdisciplinary Science Project concerned with
the hydrology in semi-arid environments (project number NAGW-2425). |
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