CONSORTIUM SUR LA
This presentation is the property of its rightful owner.
Sponsored Links
1 / 26

CONSORTIUM SUR LA CLIMATOLOGIE RÉGIONALE ET L’ADAPTATION AUX CHANGEMENTS CLIMATIQUES PowerPoint PPT Presentation


  • 46 Views
  • Uploaded on
  • Presentation posted in: General

CONSORTIUM SUR LA CLIMATOLOGIE RÉGIONALE ET L’ADAPTATION AUX CHANGEMENTS CLIMATIQUES. 2m Temperature interannual V ariability and C limate C hange S ignal from the Narccap’s RCMs Sébastien Biner, Ramon de Elia and Anne Frigon May 2012. Motivations.

Download Presentation

CONSORTIUM SUR LA CLIMATOLOGIE RÉGIONALE ET L’ADAPTATION AUX CHANGEMENTS CLIMATIQUES

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Consortium sur la climatologie r gionale et l adaptation aux changements climatiques

CONSORTIUM SUR LA CLIMATOLOGIE RÉGIONALE

ET L’ADAPTATION AUX CHANGEMENTS CLIMATIQUES

2m TemperatureinterannualVariability and ClimateChange Signal from the Narccap’sRCMs

Sébastien Biner, Ramon de Elia and Anne Frigon

May 2012


Consortium sur la climatologie r gionale et l adaptation aux changements climatiques

Motivations

  • Whylookingatinterannualvariability?

  • It is a fundamental part of the climate

  • It is variable over NorthAmerica

  • It is a « noise » to whichwecan compare the climate change « signal »

era40 [1958-1999]

From Scherrer 2010


Consortium sur la climatologie r gionale et l adaptation aux changements climatiques

TemperatureInterannualVariability

DJF

JJA

  • Willmot et Matsuura, 2009

  • Synopticscale Chinook effect

  • Sea-ice

  • Snow cover


Consortium sur la climatologie r gionale et l adaptation aux changements climatiques

TemperatureInterannualVariability

DJF

JJA

  • Willmot et Matsuura, 2009

  • Synopticscale Chinook effect

  • Sea-ice

  • Snow cover

Not in CRU2 dataset


Consortium sur la climatologie r gionale et l adaptation aux changements climatiques

How well do RCMsreproduce the interannualVariability?

  • Narccap

  • 6 RCMs

  • Simulations driven by NCEP (1980-2003)


Consortium sur la climatologie r gionale et l adaptation aux changements climatiques

Definition of a new Index to compare interannualVariability

Inspired by Gleckleret al 2008 and Scherrer 2010 wedefine a new Variability Index Ratio (VIR) :

if

if

Example :

VIR=-30% : underestimation by 30%

VIR=50% : overestimation by 50%


Consortium sur la climatologie r gionale et l adaptation aux changements climatiques

VIR for Winter 2m Temperature


Consortium sur la climatologie r gionale et l adaptation aux changements climatiques

VIR for Summer 2m Temperature


Consortium sur la climatologie r gionale et l adaptation aux changements climatiques

How well do RCMsreproduce the interannualVariability?

  • Narccap

  • 6 RCMs

  • Simulations driven by NCEP (1980-2003)

  • Simulations driven by GCMs (1971-1999)


Consortium sur la climatologie r gionale et l adaptation aux changements climatiques

VIR for Winter 2m Temperature


Consortium sur la climatologie r gionale et l adaptation aux changements climatiques

VIR for Winter 2m Temperature

ccsm

cgcm

hadcm3

gfdl


Consortium sur la climatologie r gionale et l adaptation aux changements climatiques

VIR for Winter 2m Temperature

wrf

crcm

mm5

hadrm3

rcm3

ecp2


Consortium sur la climatologie r gionale et l adaptation aux changements climatiques

VIR for Winter 2m Temperature


Consortium sur la climatologie r gionale et l adaptation aux changements climatiques

VIR for Winter 2m Temperature

CGCM3 drivenRCMssharecommonunderestimation


Consortium sur la climatologie r gionale et l adaptation aux changements climatiques

VIR for Winter 2m Temperature

SomeRCMs are sensible to the driving GCM …


Consortium sur la climatologie r gionale et l adaptation aux changements climatiques

VIR for Winter 2m Temperature

… whileother are less sensible


Consortium sur la climatologie r gionale et l adaptation aux changements climatiques

VIR for Summer 2m Temperature


Consortium sur la climatologie r gionale et l adaptation aux changements climatiques

VIR for Summer 2m Temperature

CCSM drivenRCMssharecommonoverestimation


Consortium sur la climatologie r gionale et l adaptation aux changements climatiques

VIR for Summer 2m Temperature

RCMs tend to overestimatevariability in the Gulf of Mexico region


Consortium sur la climatologie r gionale et l adaptation aux changements climatiques

Climate Change in a signal to noise Paradigm

  • In order to appreciate the strength of the climate change signal, it has to becompared to the variabilitywhichrepresents the range of temperatureinside of whichwe are used to live (adapted).

  • Climate change = signal =

  • Variability = noise =

  • Expectednumber of Yearsbefore Emergence (EYE) :

  • Wheretarepresent the studentdistribtution value for a givena % value (typicallya=95%)


Consortium sur la climatologie r gionale et l adaptation aux changements climatiques

CC for Winter Temperature

North/South gradient


Consortium sur la climatologie r gionale et l adaptation aux changements climatiques

CC for SummerTemperature

Maximum heating over US

Minmumheating over northern part


Consortium sur la climatologie r gionale et l adaptation aux changements climatiques

EYE for Winter Temperature

Values in 30-60 years range


Consortium sur la climatologie r gionale et l adaptation aux changements climatiques

EYE for Winter Temperature

Values in 30-60 years range

Pattern dominated by variability


Consortium sur la climatologie r gionale et l adaptation aux changements climatiques

EYE for SummerTemperature

Values in the 20-40 years range over US and South Canada

Region of low CC dominate pattern


Consortium sur la climatologie r gionale et l adaptation aux changements climatiques

Conclusions

  • Ability of RCMs to reproduce interannual variability

  • Ncep driven :

  • relatively small over/under estimation over some regions during winter.

  • general noticeable overestimation during summer, especially over southeastern US

  • GCMs driven :

  • underestimation across the domain during winter (particularly cgcm3 driven)

  • underestimation around Hudson Bay and overestimation over southeastern US during summer

  • Climate change signal and its perception

  • CC signal similar among RCMs during winter with northern gradient heating.

  • CC signal variable among RCMs during summer, heating generally more important over central US. Some cooling.

  • During winter high variability over northwest North America slows the perception of the important warming (high EYE values)

  • During summer no general EYE pattern except for RCMs with regions of low CC signal

  • Perception of CC is expected to occur faster during summer than during winter, especially over the US

  • General Conclusions similar to Hawkins and Sutton 2010


  • Login