Investigation of the Eastern Mediterranean Climate Using Regional Climate Model RegCM

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• Investigation of the Eastern Mediterranean
  Climate Using Regional Climate Model RegCM
  
• Shimon Krichak, Pinhas Alpert, Melina Dayan, Haim
  Shafir, Karin Bassat
• Department of Geophysics and Planetary Sciences,
  Faculty of Exact Sciences,Tel Aviv University

AMI 2005 March 23, 2005
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GLOWA Jordan River Project
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• TWO DIFFERENT DIRECTIONS
• Global Climate Modeling (GCM, AOGCM)
• Regional Climate Modeling (RCM)

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Global Climate ModelingThe aimTo simulate real
climate andclimate change processes
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Regional Climate ModelingThe aimTo
downscale the GCM results
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RCM

• RCM can not correct large-scale biases in GCM
  results
• RCMs describe processes at horiz. scales on the
  order of 10 50 km.
• Convective processes occur at horizontal scales
  on the order 1 km.
• In models, an inadequate representation of
  convective can significantly increase the
  uncertainty of the model predictions.

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• ICTP Community
• Regional Climate Hydrostatic Model
  (RegCM)
• Dynamics MM4-MM5
• (Giorgi 1994..2005)

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Nonhydrostic models (DX lt 10 km) CLM, MM5
http//www.mmm.ucar.edu/mm5/ Hydrostatic models
(DX gt 10 km) ICTP-RegCM http//www.ictp.trieste.it
/pubregcm/RegCM3/ Very complex computing systems
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RegCM3 (Giorgi et al)
Balanced surface physics Sulfate
aerosol effects (direct indirect)
Large-Scale predicted cloudiness and
precipitation Subgrid Topography and Landuse
Scheme Tuning options for cumulus
convection Soil moisture initialization according
to the vegetation types
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RegCM3 applications at TAU Downscaling
Reanalysis Data Downscaling AOGCM Data
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DOWNSCALING NNRP DATA 1981-2002
NNRP based RegCM3 run at TAU 1985-1989
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Downscaling AOGCM data (In progress
at TAU) ICTP RegCM PRUDENCE (50km/14L) results
are available
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STRATEGY OF THE SIMULATION RUNS in GLOWA JR(as
developed for EU Prudence Project)

• 1961-1990 For the present-day conditions the
  RCM are performed using the HadAMH (AGCM)
  simulation results based on the observed SST data
  during the period.

2071-2100 Data for the future climate runs -
from the perturbation experiments using the same
AGCM forced by SST anomalies taken from the
corresponding fully coupled OAGCM course
resolution HadCM3 experiments (scenarios A2
B2- Special report on Emission Scenarios, IPCC).
Other sources of GCM data available ECHAM, NASA
finite volume GCM ) FVGCM(
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RegCM runs Performed at Int. Center for Teor.
Phys. Trieste, Italy by F. Giorgi, X. Bi, J.
Palin cooperation with TAU under the EU Prudence
project

• ICTP/NCAR RegCM
• 50 km
• 119 x 98 x 14
• HadAMH SST, GHG Sulfate
• Aerosol effects (direct indirect)
• Simulations
• Reference run
• 1961-1990
• A2 B2 Scenario runs
• 2071-2100

• Mediterranean Focused

South-eastern Mediterranean
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Daily averages of the following 15 fields
T_2m (K) Precipitation (mm/day)
Total cloudiness (Fraction)
Evapotranspiration (mm/day) total runoff
(mm/d) soil moisture (mm)
Surface pressure (hPa) MSLP (hPa)
T_2m_max (K) T_2m_min (K) 2m
specific humidity (kg/kg) net and
downward SW and LW radiation (W/m2)

positive downward 2m relative humidity
(Fraction) optional Potential
evaporation (mm/d) optional
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• ICTP RegCM
• Reference-Scenario runs
• RESULTS

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Climate change estimates over SEM region ICTP
estimates
T2m oC
Prec mm
T2m mean T Prec mean prec MeP mean
prec-MeP mean precTM-Tmax PVC prec var
coeff TSTD-Temp St Dev
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Climate change estimates over SEM region ICTP
estimates
MDSL Max Dry Spell Lengh MaP-Max
Precip(1,3,5d)PIN-Prec Intens NWD- Num. wet days
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Statistical interpretation of the RCM results is
required to eliminate biases at particular
locations (height, surface types, etc.)
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Statistical downscaling (interpretation)of the
RCM modeling results at selectedlocations with
the observation dataFrequency correction
Dequie(2004)
Sorting 2 series of 30x90 daily values
Correction method for model values (present and
future)
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Dequie(2004)
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Directions for future analyses

• Temperature Number of days per year with Tmin lt
  -5
• Number of days per year with Tmax gt 35
• Number of days per year during which Tmax exceeds
  30 for at least 10 consecutive days
• Precipitation Number of wet days
• Number of days per year with gt 20 mm
• Max no. of consecutive dry days
• Greatest 5-day rainfall

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• SUMMARY
• According to HadCM RegCM simulates a warming
  varying in the range of 4.5 oC over the large
  SEM region (Egypt Syria) in the A2 scenario,
  while the warming in 1 oC lower in the B2
  scenario. Precipitation slightly decreases over
  the SEM in the winter, with similar signals in
  the two scenarios. Interannual variability
  increases in DJF for precipitation (in the A2
  40). Interannual variability increases in DJF
  for temperature (in the A2 18). The intensity of
  daily precipitation events and the magnitude of
  maximum precipitation events shows predominant
  decrease. The maximum length of dry spells
  increases in winter (1.5d B2).
• Over Israel ..?
• According to other AOGCMs?