SCIENCE DRIVER

1
Historical Evaluation of Hydrologic Components of
CESM and CMIP5 Models Integrated Assessment
Boutique Du, Enhao (edu_at_lbl.gov), Alan Di
Vittorio, William D. Collins
SCIENCE DRIVER

• Development of Land surface model depends on the
  rigorous calibration and validation against
  observations.
• Hydrologic components of Community Earth System
  Model (CESM) and other CMIP5 climate models have
  not been fully assessed at pixel scale.
• Surface soil moisture controls partitioning of
  sensible and latent heat, and surface runoff and
  infiltration. Feedback between soil moisture and
  precipitation may affect atmosphere circulation
  in large scale.
• Future trend of runoff, hence water supply, as a
  result of increasing concentrations of greenhouse
  gas remains debated.
• The objectives of this study are to
• evaluate fidelity of the hydrology components in
  climate models against observation
• identify sources of uncertainty and factors that
  are responsible for the biases

Kolyma Range
Himalaya
Monthly runoff
Monthly surface soil moisture
MODELS AND DATA (SOIL MOISTURE AND RUNOFF)
CMIP5 models (historical runs, ensemble
r1i1p1) CCSM4 (NCAR), HadCM3 (Hadley Centre),
MIROC5 (AORI ), GFDL-CM3 (NOAA/GFDL), CSIRO-Mk3
(CSIRO), BCC-csm1 (BCC), MRI-ESM1 (MRI),
FGOALS-g2 (IAP), GISS-E2-R (NASA/GISS) Moisture
content in upper portion of soil column ESA
(European Space Agency) soil moisture CCI
project Runoff World Meteorological Organization
GRDC (Global Runoff Data Center) Meteorologic
forcing crosscheck experiment design
SCIENCE IMPACT
RESULTS AND DISSCUSIONS

• Conclusions
• Areas where hydrologic variable biases prone to
  occur include high latitude (permafrost),
  mountains, and densely-vegetated tropical zones
• Precipitation from climate model has led to
  overestimation of runoff in mountain ranges and
  tropical zones. Temperature and humidity offset
  the precipitation effects in the land surface
  modeling, but caused drier surface in high
  latitudes
• CLM algorithms need to be improved in Amazon and
  permafrost on evapotranspiration (tropical
  forest) and freeze-thaw (permafrost) mechanisms