Q. In your telephone conversation with me you recalled the Tucson meeting of 1973, at which a group of researchers decided they needed good information on the last century's worth of temperatures. At the time, this was a major research undertaking; the material was difficult to access and required much work to standardize. This kind of work should have been routine for NOAA, which however had been doing none of it. Now it has in fact become routine.
What meeting was this -- what organization, etc. -- and do I have the date right?
A. The meeting was called by Hal Fritts who was funded under ARPA (Advanced Research Projects Agency) to do paleoclimate reconstructions. I think it must have been around 1975/76. Hitherto, he had been doing routine reconstructions of temperature & precipitation in the western U.S., but he had just started producing maps of pressure patterns "upstream" -- in the Pacific & even as far as Japan, so somebody decided it was time to review the project as it entered a "new frontier" of dendroclimatic reconstructions. Accordingly, a number of people were invited to participate in a review session. I recall the following participants: J.Murray Mitchell, P.M. Kelly, H.F. Diaz...but there were others, and of course many people from the Tree Ring Lab. in Tucson. I had just completed my Ph.D. which focused on early fort records from the western U.S., and in that work I had come into contact with Hal Fritts and Murray Mitchell, both of whom were very helpful & supportive.
Q. What was the group that formulated this research program? What individuals were involved?
A. During this meeting, we met one evening to discuss the need for long-term temperature data that could better define the nature of global and regional temperature change during the 19th and 20th centuries. Murray Mitchell had published some plots of global temperature (decadal means, as I recall) showing a warming from the mid-19th century, but there was at that time no good database of homogeneous data. In fact, homogeneity of data was a large part of the discussions. Anyway, we decided that it would be a good idea to try and get funding to develop a record of global temperature, based more reliably on quality-controlled sources. Three of us -- Mick Kelly, Henry Diaz and I -- subsequently wrote a proposal to the Dept of Energy (which was getting involved in climate variability research in relation to CO2 & energy policy issues), and were supported to assemble a global database of temperature data, taking into account all of the problems of changing observation times, instrumentation etc, as well as different observational protocols across country boundaries. The contract was to UMass, with sub-contracts to NOAA (Diaz) and the Climatic Research unit, University of East Anglia, U.K. (Kelly). Mick Kelly was later replaced by Phil Jones who became the UEA P.I., and lead author on many papers arising from the work. He has continued to pursue studies of the instrumental records and is widely regarded as a world expert on the subject. Most users of global land surface temperature databases now use the database we originally assembled, plus a marine data set assembled by NOAA and the U.K. Meteorological Office (by Folland and Parker).
Q. What agencies did you approach for support for the project (or series of projects)?
A. Only the Dept. of Energy, as far as I can remember. Following the funding on temperature data, we were also funded to work on global precipitation data.
Q. Did you experience any difficulty getting support?
A. As far as I can tell, the first funding started in 1981, so there must have been a delay in getting funding following the Tucson meeting.
Q. What was the outcome of the research, and how long did it take to generate conclusions?
A. I think the research generated a lot of interest in global temperature change, although it was paralleled by an awareness of CO2 change and potential anthropogenic effects. Several papers were written about the observed temperature and precipitation changes, of which the Jones et al (1986) and Bradley et al (1987b) were probably the most significant:
Bradley, R.S. and Jones, P.D., 1986: Data bases for detecting CO2-induced climatic change. Chapter 2, in: Detection of CO2-Induced Climatic Change, MacCracken, M. and Luther, F. (eds.), U.S. Department of Energy, Washington D.C.
Jones, P.D., Raper, S.C.B., Bradley, R.S., Diaz, H.F., Kelly, P.M. and Wigley, R.M.L., 1986: Northern Hemisphere surface air temperature variations, 1851-1984. Journal of Climate & Applied Meteorology, 25, 161-179
Bradley, R.S., Diaz, H.F., Kiladis, G.N. and Eischeid, J.K., 1987a: ENSO signal in continental temperature and precipitation records. Nature, 327, 497-501.
Bradley, R.S., Diaz, H.F., Eischeid, J.K., Jones, P.D., Kelly, P.M. and Goodess, C.M., 1987b: Precipitation fluctuations over Northern Hemisphere land areas since the mid-19th century. Science, 237, 171-175.
Bradley, R.S., 1988: The explosive volcanic eruption signal in northern hemisphere continental temperature records. Climatic Change, 12, 221-243.
Diaz, H.F., Bradley, R.S. and Eischeid, J.L., 1989: Precipitation fluctuations over global land areas since the late 1800s. Journal of Geophysical Research, 94, D1, 1195-1210.
Q. What role did this research play in the overall history of the discipline; has the field taken a new direction since then?
A. I think we made a contribution to the emerging debate over global warming by kicking off work on a credible database. Subsequently this kind of work was taken over by various national agencies, such as NOAA. Our focus was on monthly mean data; more recently the focus has turned to assembling homogeneous sets of daily data.
Q. You also recalled hearing Jack Eddy present his 1976 paper on the Maunder Minimum. People immediately recognized that this was an important paper, and he was mobbed after the presentation by people asking for preprints.
Could you say more about the meeting -- what were expectations prior to the presentation; what did people know of Eddy's work? This was certainly not the first time that the question of solar variability had been mooted. So what was it that made Eddy's paper so groundbreaking?
A. The meeting was a AAAS meeting in Boston. I think the paper aroused a lot of interest because it re-focused attention on the possibility that solar variability was directly involved in temperature change (often the Maunder Minimum is incorrectly assumed to be synonymous with the "Little Ice Age"). He also drew attention to the difficulties of explaining solar cycles, when there was evidence that the "cycles" had periodically stopped.
Raymond S. Bradley
Professor and Head
of Department
Department of Geosciences
University of Massachusetts
Amherst,
MA 01003-5820
Tel: 413-545-2120
Fax:
413-545-1200
Climate System Research Center: 413-545-0659
Climate System Research Center Web Page: <http://www.geo.umass.edu/climate/climate.html>
Paleoclimatology Book Web Site (1999): http://www.geo.umass.edu/climate/paleo/html