Increase in the Asian SW Monsoon During the Past Four Centuries ----------------------------------------------------------------------- World Data Center for Paleoclimatology, Boulder and NOAA Paleoclimatology Program ----------------------------------------------------------------------- NOTE: PLEASE CITE CONTRIBUTORS WHEN USING THIS DATA!!!!! NAME OF DATA SET: Increase in the Asian SW Monsoon During the Past Four Centuries LAST UPDATE: 7/2002 (Original Receipt by WDC Paleo) CONTRIBUTORS: David M. Anderson, Jonathan T. Overpeck, Anil K. Gupta IGBP PAGES/WDCA CONTRIBUTION SERIES NUMBER: 2002-049 SUGGESTED DATA CITATION: Anderson, D.M., et al., 2002, Increase in the Asian SW Monsoon During the Past Four Centuries, IGBP PAGES/World Data Center for Paleoclimatology Data Contribution Series # 2002-049. NOAA/NGDC Paleoclimatology Program, Boulder CO, USA. ORIGINAL REFERENCE: Anderson, D. M., Overpeck, J. T., and Gupta, A. K., 2002, Increase in the Asian SW Monsoon During the Past Four Centuries. Science, Volume 297, Number 5581, 26 July 2002. ADDITIONAL REFERENCES: Altabet, M. A., Higginson, M. J. & Murray, D. W. 2002. The effect of millennial-scale changes in Arabian Sea denitrification on atmospheric CO2. Nature 415, 159-162. Guo, Z. et al. 1996. High frequency pulses of East Asian Monsoon climate in the last two glaciations: link with the North Atlantic. Climate Dynamics 12, 701-709. Guo, Z. T. et al. 2002. Onset of Asian desertification by 22 Myr ago inferred from loess deposits in China. Nature 416, 159-163 (2002). Porter, S. C. & Zhisheng, A. 1995. Correlation between climate events in the North Atlantic and China during the last deglaciation. Nature 375, 305-308. Ren, G. 1998. Pollen evidence for increased summer rainfall in the medieval warm period at Maili, Northeast China. Geophysical Research Letters 25, 1931-1934. Wang, L. et al. 1999. Holocene variations in Asian monsoon moisture: a bidecadel sediment record from the South China Sea. Geophysical Research Letters 26, 2889-2892. GEOGRAPHIC REGION: Arabian Sea, Indian Ocean PERIOD OF RECORD: Holocene DESCRIPTION: Anderson et al. 2002 Faunal Abundance data from Arabian Sea Box Cores. Cores and locations RC2735 (18° 14'N, 57° 36'E, water depth 498 m, core length 42 cm), RC2730 (18° 13'N, 57°41' E, water depth 698 m, core length 51 cm). ABSTRACT: Climate reconstructions reveal unprecedented warming in the last century, however little is known about trends in aspects such as the monsoon. We reconstructed the monsoon winds for the last 1,000 years using fossil Globigerina bulloides abundance in box cores from the Arabian Sea, and found that monsoon wind strength increased during the past 4 centuries, as the northern hemisphere warmed. We infer that the observed link between Eurasian warmth/ snow cover and the SW monsoon persists on the centennial scale. Alternately, the forcing implicated in the warming trend (volcanic aerosols, solar output, greenhouse gases) may directly affect the monsoon. Either interpretation is consistent with the hypothesis that the SW monsoon strength will increase during the coming century as greenhouse gas concentrations continue to rise and northern latitudes continue to warm. DATA: Core RC2730: depth is depth in core in mm age is yearAD coarse is coarse fraction percentage carb is calcium carbonate percent measured on a leco bull is percent G. bulloides relative to all other planktic foraminifers depth30 age coarse carb bull 1 -36 27.1 38 3 -17 23.9 55.6 34 5 2 20.6 54.6 27 7 21 16.0 52.8 24 9 40 17.0 53.1 25 11 59 13.5 52.6 25 13 78 10.0 50.1 28 15 97 8.8 48.3 17 17 116 8.4 49.1 15 19 135 7.3 48.0 21 21 154 7.8 46.5 18 23 174 7.1 46.4 15 25 193 6.6 46.7 25 29 231 6.5 45.7 23 31 250 7.4 45.4 15 33 269 6.8 45.9 15 35 288 6.5 46.3 10 37 307 7.4 45.9 7 39 326 7.0 46.9 8 41 345 6.5 46.2 8 43 364 6.7 44.7 10 45 383 6.1 46.6 9 47 402 6.9 45.7 17 49 421 7.1 44.5 12 51 440 5.1 44.8 13 53 459 5.5 44.3 10 55 478 5.2 44.9 9 57 497 6.1 44.7 9 59 516 6.0 43.8 8 61 535 5.0 44.1 12 63 554 5.5 43.6 8 65 574 6.2 43.6 16 67 593 5.4 43.5 12 69 612 5.4 43.6 14 71 631 5.4 44.3 13 73 650 4.9 42.5 17 75 669 4.5 42.8 15 77 688 4.7 42.5 14 79 707 4.8 42.9 12 81 726 5.0 43.3 11 83 745 5.3 42.7 15 85 764 5.4 45.0 14 87 783 5.6 41.7 11 89 802 6.3 43.7 12 91 821 6.5 43.0 8 93 840 4.5 43.0 10 95 859 5.3 41.7 9 97 878 5.5 43.4 16 99 897 4.3 43.3 14 Core RC2735: depth is depth in core in mm depth30 is equivalent depth in RC2730, used in assigning ages from the dated core age is yearAD coarse is coarse fraction percentage carb is calcium carbonate percent measured on a leco bull is percent G. bulloides relative to all other planktic foraminifers depth35 depth30 age coarse carb bull 1 0 -36 34 3 1 -23 15.8 48.8 29 5 3 -10 13.2 45.3 32 7 4 3 10.5 43.9 27 9 5 16 32 11 7 29 8.3 44.2 32 13 8 42 7.2 43.9 31 15 10 55 5.7 42.6 29 17 11 68 5.2 41.8 28 19 12 81 -99 21 14 94 3.2 41.2 31 23 15 108 2.3 41.2 23 25 16 121 1.9 40.4 29 27 18 134 1.5 40.2 24 29 19 147 25 31 21 160 1.3 40.9 27 33 22 173 1.6 39.4 28 35 23 186 1.4 39.5 26 37 25 199 1.4 39.2 24 39 26 212 26 41 27 225 1.8 38.2 20 43 29 238 1.8 37.1 24 45 30 251 1.6 23 47 32 264 1.5 37.7 20 49 33 277 -99 51 34 290 1.6 37.2 18 53 37 316 2 37.6 14 55 39 340 1.7 38.5 14 57 42 363 1.9 39.6 13 59 44 386 1.8 39 12 61 47 410 2 39.3 14 63 49 433 2.3 39.7 14 65 52 456 2.4 39.4 15 67 54 480 2.1 39.5 23 69 57 503 2.6 39.6 21 71 59 526 3 38.5 19 73 62 550 3.3 40.9 15 75 64 573 3.5 39.3 22 77 66 596 3.2 41 20 79 69 620 4.1 41.2 22 81 71 643 3.1 41.7 20 83 74 666 4.9 44.3 18 85 76 690 4.5 44.3 28 87 79 713 4.6 42.7 29 89 81 736 5.7 42.1 22 91 84 760 5.9 43.4 25 93 86 783 5.6 43.4 27 95 88 806 4.8 44.1 16 97 91 830 4.9 41.7 21 99 93 853 4.3 40.7 17 Composite of Core RC2730 and Core RC2735: age_for_averages is the year AD mid-point of the 50 year age bin used to average all bulloides data 50_year average is the average G. bulloides percentage based on averaging all data points within a 50 year window avg-sqrt is the square root of the differences in G. bulloides percentage from the 1975 average (34) age is the year A.D. For the sediment sample g.bull is the percentage of G. bulloides relative to other planktonic foraminifers age_for_averages 50_year_avg avg-sqrt age g.bull core 1975 33.5 0.0 1986 34 rc2735 1925 28.4 2.2 1986 38 rc2730 1875 26.3 2.6 1973 29 rc2735 1825 16.8 4.0 1967 34 rc2730 1775 23.2 3.1 1960 32 rc2735 1725 23.2 3.1 1948 27 rc2730 1675 16.9 4.0 1947 27 rc2735 1625 10.2 4.8 1934 32 rc2735 1575 10.8 4.7 1929 24 rc2730 1525 13.9 4.4 1921 32 rc2735 1475 13.2 4.5 1910 25 rc2730 1425 15.0 4.2 1908 31 rc2735 1375 14.7 4.3 1895 29 rc2735 1325 17.1 4.0 1891 26 rc2730 1275 18.7 3.8 1882 28 rc2735 1225 17.9 3.9 1872 28 rc2730 1175 19.0 3.7 1856 31 rc2735 1125 13.3 4.4 1853 17 rc2730 1075 14.0 4.4 1842 23 rc2735 1834 15 rc2730 1829 29 rc2735 1816 24 rc2735 1815 21 rc2730 1803 25 rc2735 1796 18 rc2730 1790 27 rc2735 1777 28 rc2735 1776 15 rc2730 1764 26 rc2735 1757 25 rc2730 1751 24 rc2735 1738 26 rc2735 1725 20 rc2735 1719 23 rc2730 1712 24 rc2735 1700 15 rc2730 1699 23 rc2735 1686 20 rc2735 1681 15 rc2730 1662 10 rc2730 1660 18 rc2735 1643 7 rc2730 1634 14 rc2735 1624 8 rc2730 1610 14 rc2735 1605 8 rc2730 1587 13 rc2735 1586 10 rc2730 1567 9 rc2730 1564 12 rc2735 1548 17 rc2730 1540 14 rc2735 1529 12 rc2730 1517 14 rc2735 1510 13 rc2730 1494 15 rc2735 1491 10 rc2730 1472 9 rc2730 1470 23 rc2735 1453 9 rc2730 1447 21 rc2735 1434 8 rc2730 1424 19 rc2735 1415 12 rc2730 1400 15 rc2735 1396 8 rc2730 1377 22 rc2735 1376 16 rc2730 1357 12 rc2730 1354 20 rc2735 1338 14 rc2730 1330 22 rc2735 1319 13 rc2730 1307 20 rc2735 1300 17 rc2730 1284 18 rc2735 1281 15 rc2730 1262 14 rc2730 1260 28 rc2735 1243 12 rc2730 1237 29 rc2735 1224 11 rc2730 1214 22 rc2735 1205 15 rc2730 1190 25 rc2735 1186 14 rc2730 1167 11 rc2730 1167 27 rc2735 1148 12 rc2730 1144 16 rc2735 1129 8 rc2730 1120 21 rc2735 1110 10 rc2730 1097 17 rc2735 1091 9 rc2730 1072 16 rc2730 1053 14 rc2730