Sensitivity Analysis of an OfftheShelf Land Surface Model

1
Sensitivity Analysis of an Off-the-Shelf Land
Surface Model

• Chinedu T.J. Ekwueme
• Ecology Emphasis Group
• PI Manuel Gimond
• SLSTP Trainee 2004

2
Introduction/Background

• Changes in land surface energy fluxes,
  due to different land cover types, can induce
  changes in local weather patterns. Surface
  meteorological conditions are influenced in large
  part by the land-surface boundary. Therefore,
  land surface heat and water fluxes are important
  input components to meteorological models used to
  predict weather and climate. The land surface
  model (LSM) used in this project is called Noah.
  Noah is an off-the-shelf open source model
• Knowing the sensitivity of Noah to each
  input parameter (wind speed, air temperature,
  solar radiation, downwelling longwave radiation,
  pressure, humidity, albedo, and vegetation
  fraction) allows for proper allocation of
  resources in acquiring input parameter data.
  This results in a more cost-effective method to
  calibrate and validate the land surface model.

3
Materials/Methods

• For each simulation, one input variable was
  modified using set intervals while keeping the
  rest of the variables constant. Noahs output
  variables were then compared with input variables
  to assess the models degree of sensitivity to
  each input variable. This process was repeated
  for all 8 input variables resulting in 111
  simulations.

4
Conclusion

• The results presented here allows one to derive
  empirical equations relating Noahs sensitivity
  of the state variables to the input variables.
• The empirical equations could then be used to
  assess required input precision given needed
  output accuracy.