AGU Fire Poster

1
Impacts of Land Use Changes on Californias
Climate Hideki Kanamaru (hkanamaru_at_ucsd.edu),
Masao Kanamitsu Experimental Climate Prediction
Center, Scripps Institution of Oceanography

• California has seen a huge change in land use
  since mid-1800s with a sharp increase in
  population. This study investigates the role of
  land use changes had on Californias climate.
• This study is a part of model intercomparison
  project of land use change research for
  California (MM5 and RegCM3 are other
  participating models).

JUL
JAN

• The RSM is nested within the Global Spectral
  Model (GSM).
• Physics and dynamics are consistent with the
  NCEP/NCAR reanalysis model.
• Spectral formulation of difference between global
  and regional fields.
• Land surface model is OSU2 with two soil layers.

• Areas with significant temperature changes
  (beyond variance from the pre-settlement ensemble
  run) are shaded in colour.
• Diurnal temperature range (DTR) is reduced in
  irrigated land due to decreased daily maximum
  temperature.
• DTR is slightly increased in urban land due to
  increased daily maximum temperature.
• Temperature changes between pre-settlement and
  modern runs are much smaller in January than
  July.
• Higher surface pressure causes wind changes in
  the valley. Small changes in precipitation
  pattern to the east of valley in mountains

• Two land cover data sets were prepared. 1
  pre-1890 pre-settlement natural vegetation and 2
  modern land cover with irrigated croplands and
  urban areas.
• In the model two distinct land covers are treated
  as
• In irrigated cropland, soil is saturated.
• In urban land, canopy resistance is very large.

• Urban land has lower albedo, less latent heat
  cooling due to lack of vegetation and drier soil,
  and more sensible heat. Tsfc increases with
  urbanization as well as T2m.
• Tmax increase (2C) is larger than Tmin increase
  (1C), so diurnal temperature range is slightly
  larger in modern run.
• January changes are smaller than July.