j. tsutsui, k. nishizawa,h. kitabata, y. yoshida (criepi, japan) acknowledgement
DESCRIPTION
Climate sensitivity of the CCM3 to horizontal resolution and interannual variability of simulated tropical cyclones. J. Tsutsui, K. Nishizawa,H. Kitabata, Y. Yoshida (CRIEPI, Japan) Acknowledgement NCAR/CRIEPI collaborative research Support from MEXT (Japanese government). Outline. - PowerPoint PPT PresentationTRANSCRIPT
Climate sensitivity of the CCM3 to horizontal resolution and interannual variability of simulated tropical cyclones
J. Tsutsui, K. Nishizawa,H. Kitabata, Y. Yoshida
(CRIEPI, Japan)
Acknowledgement
NCAR/CRIEPI collaborative research
Support from MEXT (Japanese government)
Outline
IntroductionSensitivity to horizontal resolutionModifications of physicsPerformance of simulated TCsSummary
Background / Motivation
Preparations for IPCC AR4contribution to scenario runsemphasis on regional aspects and
extreme eventslarge natural variability and model to
model differencesComputing resourceJapanese “Earth Simulator”
Objectives
To prepare higher resolution modelsCO2 scenario runs
time-slice runs
To investigate models’ performancesensitivity to various configurationsregional aspectstropical cyclones (TCs)
Model configurations
Based on CCM3.6Optimized for vector machinesT42 to T341, L18 and L26Modifications to physicscloud diagnosticsprecipitation processessurface exchange of moisture
Migrating to CAM2
Surface height (Asia)
(m)
Surface height (Japan)
(m)
Preliminary tuning
Resolution
time step (s)
T42/L18
1200
T85/L18
600
T170/L26
180
T341/L26
120
Min.RH_low 0.90 0.90 0.90 0.87
Min.RH_high 0.90 0.70 0.65 0.50
Adj.T_hack (s) 3600 1800 540 450
Adj.T_zm (s) 7200 3600 1800 900
Global annual mean (TOA)
OLR Abs. Solar
Global annual mean (surface)SW LW
SHLH
Global annual mean (precip)Total LS
Conv. ZM
DJF 200-hPa zonal windT42
T341T170
T85
JJA precipitation rateT42
T341T170
T85
JJA precipitable waterT42
T341T170
T85
Monthly precipitation rate (T341)Dec FebJan
CMAP
Model
Changes in higher resolutionsGlobal propertiesincreased precipitationdecreased water vapordecreased cloud amountnegative energy budget
Large-scale fieldsnot much differentdeficiencies left unchanged
Regional aspectsrealistic, but large-scale dependent
Further modifications
adjustment time scalesefficiency of evaporation from LS rainsurface moisture exchangeinhibition mechanism of ZM scheme
Global precipitation rateTotal ZM scheme
RHc: RH threshold for triggering ZMDifferent from Maloney and Hartmann (2001)
Precip-CAPE relationship
RHc=85% RHc=0%
daily, 20N-20S, July, Year 0006
Time series of CAPE/Precip
at 9.4N, 138.1E
RHc=85%
RHc=0%
(Yap Island)
McBride and Frank (1999) suggest weak negative correlation.
Moist static energy profileat 9.4N, 138.1E (Yap Island)
RHc=85% RHc=0%
MODEL
RAOBS
Simulated TC frequenciesDefinition•40N-40S over ocean•SLP gradient•warm-core structure
STC distributions
JJA Precipitation rateRHc=85% RHc=0%
CMAP
Ensemble simulations
T42 model with RHc=85%Observed SST from 1979 to 20009 members
Interannual variations
Interannual variations
SummaryIncreased horizontal resolution results inmore transparent for LW (could be tuned),overestimated precipitation,detailed regional climate with similar large-scale.
Partition change in convection affectscharacteristic in the tropics,frequencies of simulated TC (not depend on resoluti
ons).
Interannual variations of simulated TCs showsuccessful simulation for some seasonal activity,model's usefulness to study TC variability.