advertisement

peter huybers

50 %
50 %
advertisement
Information about peter huybers
Sports

Published on September 6, 2007

Author: Waldarrama

Source: authorstream.com

advertisement

Reconstructing Northern Hemisphere temperature over the past millennium:  Reconstructing Northern Hemisphere temperature over the past millennium Peter Huybers WHOI/Harvard Slide2:  The hockey stick (IPCC, 2001) Millennial Northern Hemisphere (NH) temperature reconstruction (blue) and instrumental data (red) from AD 1000 to 1999, adapted from Mann et al. (1999). Slide3:  Media coverage 'The [hockey stick] has often been trotted out as the clinching proof of anthropogenic warming. Skeptics have never liked this chart, which necessarily relies on statistics to infer historical temperature from tree rings. ... [McIntyre and McKitrick] allege that Dr. Mann’s statistics are inaccurate, and that the hockey stick is a mere statistical artifact.' -The Economist, Feb, 2005. Slide4:  Proxy cross-correlation with instrumental temperatures Slide5:  Leading principal component using different normalizations MM05 MBH98 Slide6:  Two normalizations of the Sheep Mountain bristlecone pine record, CA534 and#x18;and#x13; MM05 MBH98 =7 =0.1 Slide7:  Variance and normalization conventions + MBH98 x MM05 . This study Slide8:  Leading principal components and the straight average MM05 MBH98 This study Slide9:  Normalize all paleo temperature records to zero mean and unit variance between 1820 (the shortest record) and 1980. Weight records according to spatial distributionand#x18;and#x13; and then compute the average. Adjust mean and variance of the average proxy record to that of the instrumental record and correct for noise bias. Uncertainty scales as N-1/2. A simple method to estimate past temperatures Slide10:  Re-reconstruction of temperatures bias corrected average PCA method (Mann et al, 1998) Slide11:  'It is also likely that, in the Northern Hemisphere, the 1990s was the warmest decade and 1998 the warmest year' over the last 1,000 years. ---IPCC, 2001 'Likely' is defined as a 60%-99% chance. More rigorous methods are necessary Convert proxy variability into temperature Proxy type and location b) Seasonal dependence c) Non-temperature dependencies d) Age-model uncertainties 2. Estimate average Northern Hemisphere temperatures a) Spatial covariability b) Spatially dependent noise c) Multi-resolution temperature signals Slide12:  Estimating Northern Hemisphere temperature is not at the cutting edge of mathematics or statistics, but has important societal implications. Placing current warming trends in a longer term perspective requires a more rigorous statistical approach. Slide13:  Comparison of bias in reconstruction techniques cross-correlation weighted average PCA or simple average Bias corrected average Slide14:  Leading principal components and the straight average MM05 MBH98 Slide15:  Monte Carlo results using synthetic records (following MM05) Non-centered PCA typically gives hockey sticks

Add a comment

Related presentations

Related pages

Peter Huybers

Peter Huybers cv, biosketch Professor of Earth and Planetary Sciences and Environmental Science and Engineering co-director Harvard University Center for ...
Read more

Peter Huybers - Wikipedia

Peter John Huybers; Fields: Paleoclimate, Oceanography, Statistics: Institutions: Harvard University: Alma mater: Massachusetts Institute of Technology: Thesis
Read more

Peter Huybers | Department of Earth and Planetary Sciences

Peter Huybers is a Professor of Earth and Planetary Sciences at Harvard University whose research interests lie in developing a better understanding of the ...
Read more

Peter Huybers — MacArthur Foundation

Peter Huybers is a climate scientist who, by mining the wealth of often-conflicting experimental observations, has developed several influential theories ...
Read more

Peter Huybers | Harvard University Center for the Environment

Peter Huybers is an expert in ice ages and global climate change. He received his Ph.D. in climate physics and chemistry from MIT in 2004 and received a ...
Read more

Peter Huybers | Harvard John A. Paulson School of ...

Peter Huybers is a Professor of Earth & Planetary Sciences and of Environmental Science and Engineering at Harvard University whose research interests lie ...
Read more

Peter Huybers | LinkedIn

View Peter Huybers’ professional profile on LinkedIn. LinkedIn is the world's largest business network, helping professionals like Peter Huybers discover ...
Read more

PAOC Colloquium - Peter Huybers (Harvard) | MIT Department ...

Faculty and students work in a wide range of disciplines, including geology, geochemistry, geophysics, geobiology, atmospheric science, oceanography ...
Read more

Liste der MacArthur Fellows – Wikipedia

Peter Huybers, Klimawissenschaftler; James Longley, Filmregisseur; L. Mahadevan, angewandter Mathematiker; Heather McHugh, Dichterin; Jerry Mitchell ...
Read more

Peter Huybers - Harvard University

Peter Huybers' homepage ... Publications. Huybers and Langmuir Delayed CO2 emissions from mid-ocean ridge volcanism as a possible cause of late-Pleistocene ...
Read more