See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/11380880 Archaefructaceae, a New Basal Angiosperm Family Article in Science · June 2002 DOI: 10.1126/science.1069439 · Source: PubMed CITATIONS READS 389 736 6 authors, including: Ge Sun David L Dilcher Jilin University Indiana University Bloomington 59 PUBLICATIONS 1,419 CITATIONS 393 PUBLICATIONS 13,765 CITATIONS SEE PROFILE SEE PROFILE Some of the authors of this publication are also working on these related projects: Nature and Time on Earth - Project for a course and a book for virtual visits to past environments in learning programmes for university students (coordinators Edoardo Martinetto, Emanuel Tschopp, Robert A. Gastaldo) View project NECLIME - Neogene Climate Evolution in Eurasia View project All content following this page was uploaded by David L Dilcher on 23 May 2014. The user has requested enhancement of the downloaded file. Archaefructaceae, a New Basal Angiosperm Family Ge Sun; Qiang Ji; David L. Dilcher; Shaolin Zheng; Kevin C. Nixon; Xinfu Wang Science, New Series, Vol. 296, No. 5569. (May 3, 2002), pp. 899-904. Stable URL: http://links.jstor.org/sici?sici=0036-8075%2820020503%293%3A296%3A5569%3C899%3AAANBAF%3E2.0.CO%3B2-B Science is currently published by American Association for the Advancement of Science. Your use of the JSTOR archive indicates your acceptance of JSTOR's Terms and Conditions of Use, available at http://www.jstor.org/about/terms.html. JSTOR's Terms and Conditions of Use provides, in part, that unless you have obtained prior permission, you may not download an entire issue of a journal or multiple copies of articles, and you may use content in the JSTOR archive only for your personal, non-commercial use. Please contact the publisher regarding any further use of this work. Publisher contact information may be obtained at http://www.jstor.org/journals/aaas.html. Each copy of any part of a JSTOR transmission must contain the same copyright notice that appears on the screen or printed page of such transmission. The JSTOR Archive is a trusted digital repository providing for long-term preservation and access to leading academic journals and scholarly literature from around the world. The Archive is supported by libraries, scholarly societies, publishers, and foundations. It is an initiative of JSTOR, a not-for-profit organization with a mission to help the scholarly community take advantage of advances in technology. For more information regarding JSTOR, please contact [email protected]. http://www.jstor.org Wed Jan 9 14:41:14 2008 REPORTS ministration (N0AA)lClimate Prediction Center the SH middle latitudes, the SAM index used in this 38. , C. C. Hegerl, 1. Clim. 13, 1018 (2000). (CPC), Washington. DC (2000)l. Updates are available study is based solely on polar data. In practice, the time 39. M. P. Hoerling, J. W. Hurrell, T. Xu, Science 292, 90 on the Web at www.cpc.ncep.noaa.gov. series of the SAM derived from 500-hPa height anoma- (2001). 5. K. E. Trenberth, J. C. Olson, 1. Clim. 2, 1196 (1989). lies averaged over the radiosonde stations in Table 1 is 40. D. T. Shindell, R. L Miller, C. Schmidt, L. Pandolfo. 6. W. J. Randel, F. Wu, 1. Clim. 12, 1467 (1999). highly correlated with an index of the SAM based on Nature 399, 452 (1999). 7. 1. W. Hurrell, H. van Loon, Tellus 46A, 325 (1994). empirical orthogonal function analysis of gridded SH 41. D. T. Shindell, C. A. Schmidt. R. L. Miller. D. Rind, I. 8. D. W. Waugh, W. J. Randel, S. Pawson, P. A. Newman, geopotential height anomalies, as used in (24, 26, 27). Ceophys. Res. 106, 7193 (2001). E. R. Nash, J. Ceophys. Res. 104, 27191 (1999). The 500-hPa time series shown in Fig. 2 is correlated 42. J. C. Fyfe, C. J. Boer, C. M. Flato, Ceophys. Res. Lett. 9. S. Zhou, M. E. Celman, A. J. Miller, J. P. McCormack, with the corresponding leading principal component 26, 1601 (1999). Ceophys. Res. Lett. 27, 1123 (2000). time series of SH (20' to 90'5) 500-hPa geopotential 43. P. J. Kushner, I. M. Held, T. L. Delworth, 1. Clim. 14, 10. C. J. Marshall, V. Lagun, T. A. Lachlan-Cope. Int. 1. height anomalies from the NCEPINCAR reanalysis at 2238 (2001). r = 0.84, based on all calendar months of the year, Climatol., in press. 44. D. M. H. Sexton, Ceophys, Rex. Lett. 28, 3697 (2001). 11. D. C. Vaughan, C. J. Marshall, W. M. Connolley, J. C. 1979-1998. 45. M. P. Baldwin, T. J. Dunkerton, 1. Ceophys. Res. 104, King, R. Mulvaney, Science 293, 1777 (2001) and 31. The significance of the correlations in Table 3 was 30937 (1999). references therein has a summary of recent temper- estimated from the t statistic, assuming only one 46. , Science 294, 581 (2001). ature trends over Antarctica. degree of freedom for every 2 years. The significance 12. D. C. Vaughan, 5. M. Doake, Nature 379, 328 (1996). of the linkages in Fig. 3 was estimated assuming one 47. D. W. J. Thompson, M. P. Baldwin, J. M. Wallace, 1. 13. S. S. Jacobs, J. C. Comiso,]. Clim. 10, 697 (1997). degree of freedom for every year (the time series Climate, in press. 14. E. Hanna, Weather 54, 71 (1999). used in Fig. 3 consist of 6 months per year). 48. Intergovernmental Panel on Climate Change, Climate 15. S. E. Stammerjohn, R. C. Smith, Clim. Change 37, 617 32. Because the trend in the SAM accounts for a rela- Change 2007: The Science of Climate Change (Cam- (1997). tively small fraction (9%) of the total month-to- bridge Univ. Press, Cambridge, UK, 2001). 16. C. L. Parkinson, Ann. Claciol., in press. month variance during December-May from 1969- 49. P. D. Jones, I.Clim. 7, 1794 (1994). 17. Monthly mean radiosonde data for the stations listed in 1998, the fractions of the trends that are linearly 50. M. E. Kalnay et al., Bull. Am. Meteorol. Soc 77, 437 Table 1 were obtained from the NCEP with the assist- congruent with the SAM index in Fig. 3 are not (1996). ance of J. Caron and K. Trenberth at the NCAR. The strongly sensitive to shared trends in the time series. 51. C. J. Marshall,1. Clim. 15, 659 (2002). stations were chosen on the basis of the temporal For the shortest period of record considered (Decem- 52. P. M. de F. Forster, K. P. Shine, Ceophys. Res Lett. 26, continuity of their records. For each station, anomalies ber-May monthly means from 1979-2000), the total 3309 (1999). exceeding 3 SD about the long-term mean were re- fraction was found to vary by -5% when the indices 53. H. van Loon, J. Rogers, Mon. Weather Rev 106, 296 moved from the data. Cridded monthly mean surface were detrended before the calculation of the regres- (1978). air-temperature anomalies were obtained from the Cli- sion coefficients. 54. We thank K. E. Trenberth, J. Caron, and W. J. Randel mate Research Unit at the University of East Anglia 33. The correlation between the time series of 500- and (NCAR) for assistance with the Antarctic radiosonde (49). Monthly and daily means of the NCEPINCAR 30-hPa height anomalies averaged over the polar cap data; T. Gill (South African Meteorological Service) reanalysis (50) were obtained through the NOAA CB- for the April-May season is r = 0.62. The correspond- and C. Bodeker (National Institute for Water and mate Diagnostics Center. Halley station ozone data ing correlation between April-May 30-hPa height Atmospheric Research) for providing additional sta- were provided by the British Antarctic Survey. anomalies and total column ozone at Halley station tion data; P. D. Jones for providing surface tempera- 18. Data for the radiosonde stations listed in Table 1 and during the previous November is r = 0.23. tures over Antarctica; J. M. Wallace, K. E. Trenberth, gridded monthly mean surface temperature data over 34. H. K. Roscoe, A. E. Jones, A. M. Lee, Science 278, 93 M. P. Baldwin, and C. Marshall for helpful comments Antarctica are available starting from 1958. However, (1997). at various stages of this research; and H. K. Kim and because the temporal coverage of these data improved 35. H. L. Miller, R. W. Sanders, S. Solomon, 1. Ceophys. W. Higgins at the NOAA CPC for the inspiration for markedly in the late 1960s, our analysis is restricted to Res. 104, 18769 (1999). Fig. 4. D.W.J.T. is supported by the NSF under grant the period after 1969. Results based on the NCEPINCAR 36. J. W. Hurrell, Science 269, 676 (1995). CAREER: ATM-0132190. reanalysis were found to be in excellent agreement with 37. D. W.]. Thompson, j. M. Wallace, Ceophys. Res. Lett. those derived from the radiosonde data after -1979, 25, 1297 (1998). 21 December 2001; accepted 26 March 2002 which corresponds to the introduction of satellite data into the reanalysis assimilation scheme. For example. the monthly mean time series of 500-hPa geopotential height averaged over the radiosonde stations listed in Table 1 is correlated with 500-hPa geopotential height Archaefructaceae, a New Basal anomalies from the reanalysis averaged over the SH polar cap ( poleward of 605) at a level of r = 0.89 for the period 1979-1998, and the amplitude and season- Angiosperm Family ality of trends calculated from these two time series are virtually identical Results based on the NCEPINCAR Ge Sun,'* Qiang JiI2David L ~ilcher,~*Shaolin Zheng: reanalysis were found to diverge from those derived from the radiosonde data before 1979, particularly in Kevin C.