recent variability of the solar spectral irradiance and its impact on climate modelling - tosca wg1...

Clear sky UV simulations in the 21st century based on CCM predictionsRecent variability of the solar spectral irradiance and its impact on climate modelling - TOSCA WG1 Workshop, May 2012, Berlin
Stratospheric and tropospheric effects of solar activity
K. Tourpali
CCMVal-2 PIs
*
How does the Sun influence natural climate variability?
What is the role of the stratosphere - how does the exchange with the troposphere work?
Which mechanisms (top-down, bottom-up) are important for solar influences on climate?
Can climate models represent the observed signals?
Recent variability of the solar spectral irradiance and its impact on climate modelling - TOSCA WG1 Workshop, May 2012, Berlin
Observations:
Sea surface: temperatures, mean sea level pressures
Winds: Zonal, Vertical
Clouds / precipitation
Observations:
Sea surface: temperatures, mean sea level pressures
Winds: Zonal, Vertical
Mid / high latitude ‘annular modes’, especially Arctic Oscilaltion
Clouds / precipitation
SPARC CCMval Activity
Solar signal in CCMVal-2 runs
Simulation Ref-B1: Reproducing the past
transient run from 1960 - to the present
All forcings taken from observations
SPARC Report -Solar signal in CCMVal-2 runs
25N-25S
The signal in upper stratosphere is reasonably represented in models
However, there are large differences between CCMs
But also between observation data sets!
possible aliasing of signal – ENSO, volcanoes
SPARC Report - Solar signal in CCMVal-2 runs
Climate Chemistry Models
Ref-B1 of CCMVal-2
GEOSCCM
ULAQ
UMUKCA-METO
UMUKCA-UCAM
UMETRAC
*
Data and method of analysis
Inputs from CCMs (monthly averages) :
Geopotential heights (3D)
Ozone total column and profile
Analysis:
Annular mode in the Northern hemisphere winter (DJF)
geopotential heights : 850hPa, 500hPa, 10hPa
*
Regression analysis on zonal wind
focus on northern hemisphere winter
The autoregressive linear model in general form:
Courtesy of Markus Kunze
Annular mode analysis
- separated in solar maximum and minimum years
the 1st EOF pattern represents the Arctic Oscillation variability
AO-index is the normalised leading PC
Winter mean fields regressed onto this AO-index
Correlation between the AO-index and zonal mean wind and zonal mean temp
I have not touched ozone yet!
zonal wind response
Era-40
AMTRAC
CMAM
meters
Era-40
SOCOL
WACCM
meters
Era-40
AMTRAC
CMAM
meters
Era-40
SOCOL
WACCM
meters
winter 10 hPa geopotential height
Era-40
Amtrac
waccm
meters
Arctic Oscillation
A number of models with solar cycle variability reproduce this
*
What does a model with no SC show?
850 hPa
Extension of the signal in the stratosphere
Era-40
Correlation to zonal wind
850 mb AO index
*
amtrac3
Correlation to zonal wind
*
Summary (Conclusions – not there yet!)
Chemistry-Climate Models do represent the solar max vs min changes in the shape of AO
How about the vertical extension of the signal?
Do volcanic eruptions (or ENSO) disrupt the signal?
*
And, more Questions!
What are the differences in ozone and temperature if a new SSI forcing is used?
Will the stratospheric-tropospheric signals show up if another SSI forcing is used? Stronger or weaker?
Will we find a better comparison to observations?
Will our current perception of mechanisms (top-down, bottom-up) change?
*
Thank you!
*

recent variability of the solar spectral irradiance and its impact on climate modelling - tosca wg1...

Documents