Climate Field Reconstruction (CFR) Methods; MBH 1998 and 1999
Variations on the "Composite Plus Scale" (CPS) method continued to be used to produce hemispheric or global mean temperature reconstructions. From 1998 this was complemented by Climate Field Reconstruction (CFR) methods which could show how climate patterns had developed over large spatial areas, making the reconstruction useful for investigating natural variability and long term oscillations as well as for comparisons with patterns produced by climate models. The CFR method made more use of climate information embedded in remote proxies, but was more dependent than CPS on assumptions that relationships between proxy indicators and large-scale climate patterns remained stable over time.
Related rigorous statistical methods had been developed for tree ring data, with Harold C. Fritts publishing a 1991 study and a 1991 book showing methodology and examples of how to produces maps showing climate developments in North America over time. These methods had been used for regional reconstructions of temperatures, anda other aspects such as rainfall.
As part of his Phd research, Michael E. Mann worked with seismologist Jeffrey Park on developing statistical techniques for find long term oscillations of natural variability in the instrumental temperature record of global surface temperatures over the last 140 years; Mann & Park 1993 showed patterns relating to the El Niño–Southern Oscillation, and Mann & Park 1994 found what was later termed the Atlantic multidecadal oscillation. They then teamed up with Raymond S. Bradley to use these techniques on the dataset from his Bradley & Jones 1993 study with the aim of finding long term oscillations of natural variability in global climate. The resulting reconstruction went back to 1400, and was published in November as Mann, Park & Bradley 1995. They were able to detect that the multiple proxies were varying in a coherent oscillatory way, indicating both the multidecadal pattern in the North Atlantic and a longer term oscillation of roughly 250 years in the surrounding region. Their study did not calibrate these proxy patterns against a quantitative temperature scale, and a new statistical approach was needed to find how they related to surface temperatures in order to reconstruct past temperature patterns.
Read more about this topic: Hockey Stick Controversy
Famous quotes containing the words climate and/or field:
“Russian forests crash down under the axe, billions of trees are dying, the habitations of animals and birds are layed waste, rivers grow shallow and dry up, marvelous landscapes are disappearing forever.... Man is endowed with creativity in order to multiply that which has been given him; he has not created, but destroyed. There are fewer and fewer forests, rivers are drying up, wildlife has become extinct, the climate is ruined, and the earth is becoming ever poorer and uglier.”
—Anton Pavlovich Chekhov (1860–1904)
“Hardly a book of human worth, be it heaven’s own secret, is honestly placed before the reader; it is either shunned, given a Periclean funeral oration in a hundred and fifty words, or interred in the potter’s field of the newspapers’ back pages.”
—Edward Dahlberg (1900–1977)