New Horizons in Paleoclimatology Toby Ault 5 6
New Horizons in Paleoclimatology Toby Ault 5. 6. 2008
Overview: Proxy-model integration Experiment design Results Future work
Overview: Proxy-model integration Experiment design Results Future work
Overview: Proxy-model integration Experiment design Results Future work
Overview: Proxy-model integration Experiment design Results Future work
Overview: Proxy-model integration Experiment design Results Future work
Proxy-Model Integration
GCM Data: Proxy Data: 10’s of km 100’s of km Image from: http: //ipcc-wg 1. ucar. edu/wg 1/Report/AR 4 WG 1_Print_Ch 11. pdf
1°x 1° (~111 km)
Case example: the Monsoon
August, 2006 PRISM mean precip. (mm/day) http: //www. prism. oregonstate. edu/products/viewer. phtml? file=/pub/prism/us/graphics/ppt/2000 -2009/us_ppt_2006. 08. png&year=2006&vartype=ppt&month=08&status=final&zoom=yes
Observational Monsoon 0. 5˚x 0. 5˚ JJA mean precip. (mm/day) *Mitchell, T. D. , and P. D. Jones (2005), An improved method of constructing a database of monthly climate observations and associated high-resolution grids, International Journal of Climatology, 25(6), 693 -712.
CCSM 3’s Monsoon JAS mean precip. (mm/day)
CCSM 3’s Monsoon What about the future? JAS mean precip. (mm/day)
CCSM - No change GFDL - Weaker UKMO - Stronger *Joellen Russell, Pers. comm.
CCSM - No change No good consensus… Absent in other models… GFDL - Weaker Turn to proxies! UKMO - Stronger *Joellen Russell, Pers. comm.
Mid-Holocene climate http: //geochange. er. usgs. gov/sw/impacts/biology/pastclim/
Proxies in N. America
http: //www. swaebr. org/images/Packrat. jpg
Wetter summers… OR …drier winters!
Playa Lakes: Occasionally filled during Mid-Holocene Likely monsoon related… http: //en. wikipedia. org/wiki/Playa
Speleothems: Stronger Monsoon Connection to North Atlantic ITCZ shifted northward? �
Modeling 6 ka climates
PMIP (Paleoclimate Model Intercomparison Project) Mean JJA precipitation for CCSM 6 ka simulation http: //www. ncdc. noaa. gov/paleo/modelvis. html
Harrison et al. , 2003 CCSM 3 -JJA: 6 ka-0 ka (mm/day)
Harrison et al. , 2003 No Change? CCSM 3 -JJA: 6 ka-0 ka (mm/day)
GCM Data: Proxy Data: 10’s of km 100’s of km Image from: http: //ipcc-wg 1. ucar. edu/wg 1/Report/AR 4 WG 1_Print_Ch 11. pdf
GCM Data: Proxy Data: Can regional downscaling bridge this gap? 10’s of km 100’s of km
Experiment Design
Model: WRF Nesting: None Physics: Defaults X-domain: 119˚W to 110˚W Y-domain: 20˚N to 34˚N Resolution: ~30 km Time: Aug. 2 -25, 2006 T: 3 hrs
Boundary Conditions: NCEP/NCAR Reanalysis 2. 5˚x 2. 5˚ resolution
Results
Means NNRP Precipitation (mm/day) WRF
Variance NNRP WRF Precipitation variance (mm/day)2
August 2006 - NNRP Link to animation
August 2006 - WRF Link to animation
Smaller scale Better representation of mechanisms
Future Work
1. Comparison with observations 2. Better analysis of dynamics 3. Cumulus parameterization scheme 4. Downscaling modern CCSM 3 runs 5. Paleoclimate downscaling
1. Comparison with observations 2. Better analysis of dynamics 3. Cumulus parameterization scheme 4. Downscaling modern CCSM 3 runs 5. Paleoclimate downscaling
1. Comparison with observations 2. Better analysis of dynamics 3. Cumulus parameterization scheme 4. Downscaling modern CCSM 3 runs 5. Paleoclimate downscaling
1. Comparison with observations 2. Better analysis of dynamics 3. Cumulus parameterization scheme 4. Downscaling modern CCSM 3 runs 5. Paleoclimate downscaling
1. Comparison with observations 2. Better analysis of dynamics 3. Cumulus parameterization scheme 4. Downscaling modern CCSM 3 runs 5. Paleoclimate downscaling
1. Comparison with observations 2. Better analysis of dynamics 3. Cumulus parameterization scheme 4. Downscaling modern CCSM 3 runs 5. Paleoclimate downscaling
Acknowledgements: Jason Criscio, Andy Penny, and CCIT - THANKS!
- Slides: 46