﻿# 700 Year El Niño/Southern Oscillation (ENSO) Niño3.4 Index Reconstruction 
#----------------------------------------------------------------------- 
#                World Data Center for Paleoclimatology, Boulder 
#                                  and 
#                     NOAA Paleoclimatology Program 
#----------------------------------------------------------------------- 
# NOTE: Please cite Publication, and Online_Resource and date accessed when using these data. 
# If there is no publication information, please cite Investigators, Title, and Online_Resource and date accessed. 
#
#
# Online_Resource: http://www.hurricane.ncdc.noaa.gov/pls/paleox/f?p=519:1:::::P1_STUDY_ID:14632
#
# Original_Source_URL: ftp://ftp.ncdc.noaa.gov/pub/data/paleo/treering/reconstructions/enso-li2013.txt
# 
# Description/Documentation lines begin with #
# Data lines have no #
#
# Archive: Climate Reconstructions
#--------------------
# Contribution_Date
#	Date: 2013-07-03
#--------------------
# Title
#	Study_Name: 700 Year El Niño/Southern Oscillation (ENSO) Niño3.4 Index Reconstruction
#--------------------
# Investigators
#       Investigators: Li, J.; Xie, S.-P.; Cook, E.R.; Morales, M.S.; Christie, D.A.; Johnson, N.C.; Chen, F.; D'Arrigo, R.; Fowler, A.M.; Gou, X.; Fang, K.
#--------------------
# Description_and_Notes
#	Description: An index of canonical El Niño/Southern Oscillation (ENSO) variability for the past seven centuries, derived from 2,222 tree-ring chronologies 
#       from Asia, New Zealand, and North and South America. The reconstruction targets the prior winter (November-January, NDJ) Niño3.4 index, and covers 1301-2005. 
#       SST anomalies (SSTAs) are relative to the mean of observed SSTs during 1971-2000.  
#
#--------------------
# Publication 
#       Authors: Jinbao Li, Shang-Ping Xie, Edward R. Cook, Mariano S. Morales, Duncan A. Christie, Nathaniel C. Johnson, Fahu Chen, Rosanne D'Arrigo, Anthony M. Fowler, Xiaohua Gou, and Keyan Fang
#       Published_Date_or_Year: 2013-07-02     
#       Published_Title: El Niño modulations over the past seven centuries
#       Journal_Name: Nature Climate Change
#       Volume: 
#       Edition: Published online 02 July 2013
#       Issue: 
#       Pages: 
#       DOI: 10.1038/nclimate1936
#       Online_Resource: 
#       Full_Citation: 
#       Abstract: Predicting how the El Niño/Southern Oscillation (ENSO) will change with global warming is of enormous importance to society. ENSO exhibits considerable natural variability at interdecadal-centennial timescales. Instrumental records are too short to determine whether ENSO has changed and existing reconstructions are often developed without adequate tropical records. Here we present a seven-century-long ENSO reconstruction based on 2,222 tree-ring chronologies from both the tropics and mid-latitudes in both hemispheres. The inclusion of tropical records enables us to achieve unprecedented accuracy, as attested by high correlations with equatorial Pacific corals and coherent modulation of global teleconnections that are consistent with an independent Northern Hemisphere temperature reconstruction. Our data indicate that ENSO activity in the late twentieth century was anomalously high over the past seven centuries, suggestive of a response to continuing global warming. Climate models disagree on the ENSO response to global warming, suggesting that many models underestimate the sensitivity to radiative perturbations. Illustrating the radiative effect, our reconstruction reveals a robust ENSO response to large tropical eruptions, with anomalous cooling in the east-central tropical Pacific in the year of eruption, followed by anomalous warming one year after. Our observations provide crucial constraints for improving climate models and their future projections.
#------------------
# Publication 
#       Authors: Jinbao Li, Shang-Ping Xie, Edward R. Cook, Gang Huang, Rosanne D'Arrigo, Fei Liu, Jian Ma, and Xiao-Tong Zheng
#       Published_Date_or_Year: 2011-05-06     
#       Published_Title: Interdecadal modulation of El Niño amplitude during the past millennium 
#       Journal_Name: Nature Climate Change
#       Volume: 1
#       Edition: 
#       Issue: 2
#       Pages: 114-118
#       DOI: 10.1038/nclimate1086
#       Online_Resource: 
#       Full_Citation: 
#       Abstract: The El Niño/Southern Oscillation (ENSO) is the dominant mode of interannual climate variability on Earth, alternating between anomalously warm (El Niño) and cold (La Niña) conditions in the tropical Pacific at intervals of 2-8 years. The amplitude of ENSO variability affects the occurrence and predictability of climate extremes around the world, but our ability to detect and predict changes in ENSO amplitude is limited by the fact that the instrumental record is too short to characterize its natural variability. Here we use the North American Drought Atlas - a database of drought reconstructions based on tree-ring records - to produce a continuous, annually resolved record of ENSO variability over the past 1,100 years. Our record is in broad agreement with independent, ENSO-sensitive proxy records in the Pacific and surrounding regions. Together, these records indicate that ENSO amplitude exhibits a quasi-regular cycle of 50-90 years that is closely coupled to the tropical Pacific mean state. Anomalously warm conditions in the eastern Pacific are associated with enhanced ENSO variability, consistent with model simulations. The quasi-periodic ENSO amplitude modulation reported here offers a key observational constraint for improving models and their prediction of ENSO. 
#------------------
# Funding_Agency 
#       Funding_Agency_Name: US National Science Foundation
#       Grant: 
#------------------
# Funding_Agency 
#       Funding_Agency_Name: National Basic Research Program of China
#       Grant: 2012CB955600
#------------------
# Funding_Agency 
#       Funding_Agency_Name: US National Oceanic and Atmospheric Administration
#       Grant: 
#------------------
# Funding_Agency 
#       Funding_Agency_Name: Japan Agency for Marine-Earth Science and Technology
#       Grant: 
#------------------
# Funding_Agency 
#       Funding_Agency_Name: FONDECYT
#       Grant: 1120965
#------------------
# Funding_Agency 
#       Funding_Agency_Name: CONICYT/FONDAP
#       Grant: 15110009
#------------------
# Funding_Agency 
#       Funding_Agency_Name: CONICET and IAI
#       Grant: CRN2047
#------------------
# Site_Information 
#       Site_Name: Nino3.4
#       Location: Ocean>Pacific Ocean>Eastern Pacific Ocean
#	Country:  
#	Northernmost_Latitude: 5.0
# 	Southernmost_Latitude: -5.0
# 	Easternmost_Longitude: -120.0
# 	Westernmost_Longitude: -170.0
# 	Elevation: 0 m  
#------------------
# Data_Collection   
#	Collection_Name: Li2013Nino3.4
#	Earliest_Year: 1301
#	Most_Recent_Year: 2005
#	Time_Unit: AD
#	Core_Length: m
#	Notes: 
#------------------
# Chronology: 
# 
#
#
# 	
#----------------	
# Variables 
#
# Data variables follow (have no #)
# Data line variables format:  Variables one per line, shortname-tab- 9 components: what, material, error, units, seasonality, archive, detail, method, C or N for Character or Numeric data
## age_AD	age, , , AD, , , , ,N
## sst.anom	Sea Surface Temperature (SST) anomaly, , , deg C, annual, , vs. 1971-2000 mean, ,N 
#----------------
# Data:
# Data lines follow (have no #)
# Data line format - tab-delimited text, variable short name as header
# Missing Values:  
age_AD	sst.anom
1301	0.398
1302	0.097
1303	0.676
1304	-0.137
1305	-0.586
1306	0.828
1307	0.346
1308	-1.753
1309	-0.23
1310	0.137
1311	-0.255
1312	-0.195
1313	0.449
1314	1.502
1315	-0.783
1316	-1.802
1317	-1.696
1318	-0.801
1319	0.182
1320	-0.346
1321	0.738
1322	-0.412
1323	-0.77
1324	-1.079
1325	-1.481
1326	-0.142
1327	0.287
1328	0.255
1329	0.201
1330	0.63
1331	-0.123
1332	-0.112
1333	0.056
1334	-0.231
1335	-0.179
1336	-1.965
1337	0.097
1338	-0.356
1339	-0.188
1340	-0.839
1341	-0.179
1342	0.732
1343	-0.313
1344	-0.887
1345	0.03
1346	0.452
1347	0.798
1348	-0.096
1349	-0.204
1350	-0.558
1351	0.286
1352	0.066
1353	-0.03
1354	0.405
1355	-0.44
1356	-0.018
1357	0.544
1358	0.564
1359	0.114
1360	-0.819
1361	0.546
1362	0.296
1363	-0.343
1364	0.802
1365	-0.233
1366	0.393
1367	-0.399
1368	1.407
1369	-0.77
1370	-0.89
1371	-1.12
1372	-1.228
1373	-1.052
1374	1.325
1375	-1.322
1376	-0.653
1377	-0.574
1378	-0.123
1379	-0.613
1380	0.24
1381	1.424
1382	-1.018
1383	-1.436
1384	0.099
1385	0.77
1386	0.137
1387	-0.823
1388	-0.561
1389	-1.418
1390	-1.839
1391	-0.665
1392	0.305
1393	0.635
1394	0.861
1395	-0.229
1396	-0.77
1397	-0.639
1398	-1.194
1399	-1.731
1400	-0.943
1401	-0.564
1402	0.386
1403	0.043
1404	2.24
1405	-0.178
1406	-0.772
1407	-1.226
1408	0.364
1409	0.864
1410	-0.987
1411	-0.512
1412	0.648
1413	-0.369
1414	-0.869
1415	-0.866
1416	0.263
1417	1.135
1418	-0.048
1419	0.108
1420	-0.305
1421	0.191
1422	-1.49
1423	-1.318
1424	0.239
1425	1.838
1426	-0.63
1427	-0.176
1428	-0.012
1429	-1.065
1430	-0.713
1431	-0.601
1432	1.092
1433	-0.068
1434	0.337
1435	-1.333
1436	-0.125
1437	-0.047
1438	-0.459
1439	-0.035
1440	-0.732
1441	0.257
1442	-0.927
1443	0.218
1444	0.29
1445	-0.972
1446	-0.473
1447	-0.387
1448	0.332
1449	-0.385
1450	0.406
1451	0.472
1452	0.367
1453	-1.634
1454	-1.651
1455	-1.992
1456	-0.488
1457	-0.034
1458	0.616
1459	-0.688
1460	0.526
1461	-0.104
1462	-0.071
1463	-0.254
1464	-0.788
1465	-0.511
1466	-0.152
1467	0.78
1468	0.433
1469	0.385
1470	-0.814
1471	-0.602
1472	-0.796
1473	-0.683
1474	-0.849
1475	-0.648
1476	-0.71
1477	0.969
1478	0.413
1479	0.868
1480	-0.478
1481	-0.567
1482	0.413
1483	-1.019
1484	1.431
1485	1.634
1486	0.131
1487	0.255
1488	0.121
1489	0.931
1490	-1.109
1491	-0.669
1492	-1.118
1493	0.954
1494	-1.021
1495	-1.984
1496	-0.057
1497	-0.933
1498	0.671
1499	0.861
1500	0.019
1501	-0.872
1502	-0.282
1503	0.316
1504	0.661
1505	0.648
1506	-1.483
1507	-0.099
1508	-0.204
1509	-0.87
1510	-1.157
1511	0.642
1512	-0.683
1513	-1.445
1514	0.468
1515	-0.841
1516	-1.644
1517	-0.129
1518	-0.321
1519	-0.198
1520	0.646
1521	-0.445
1522	-0.832
1523	-0.649
1524	-1.357
1525	-0.914
1526	1.288
1527	-0.151
1528	-2.119
1529	-0.553
1530	0.431
1531	0.201
1532	-1.039
1533	-0.831
1534	0.089
1535	-1.222
1536	-0.4
1537	0.046
1538	-1.499
1539	0.191
1540	0.231
1541	0.012
1542	-0.513
1543	0.755
1544	-1.028
1545	0.524
1546	-1.283
1547	-0.387
1548	-0.684
1549	-1.364
1550	0.01
1551	0.051
1552	-0.602
1553	-0.544
1554	-0.404
1555	0.401
1556	-0.077
1557	-0.415
1558	-0.295
1559	-0.43
1560	-0.172
1561	-1.14
1562	-0.438
1563	-0.211
1564	-0.019
1565	0.324
1566	-0.795
1567	-1.159
1568	-1.027
1569	0.312
1570	-0.256
1571	-0.968
1572	-1.656
1573	-2.104
1574	-0.127
1575	0.829
1576	-0.869
1577	-0.142
1578	-0.835
1579	0.126
1580	0.115
1581	1.247
1582	0.976
1583	-0.077
1584	-1.204
1585	-0.524
1586	-0.348
1587	-0.658
1588	-0.045
1589	-1.279
1590	-0.467
1591	-0.792
1592	0.124
1593	-1.162
1594	0.709
1595	-1.169
1596	-1.724
1597	-0.065
1598	-0.704
1599	-1.053
1600	-2.25
1601	-1.363
1602	-1.65
1603	-0.942
1604	0.739
1605	-0.064
1606	0.785
1607	0.959
1608	-0.04
1609	0.779
1610	2.28
1611	-0.768
1612	0.061
1613	-0.358
1614	0.507
1615	0.071
1616	-0.556
1617	-0.359
1618	0.092
1619	0.28
1620	0.515
1621	0.061
1622	-1.454
1623	-2.419
1624	-1.996
1625	-1.71
1626	-2.842
1627	-0.531
1628	-0.516
1629	1.42
1630	0.251
1631	0.805
1632	-0.036
1633	-0.518
1634	0.611
1635	1.487
1636	0.393
1637	-0.778
1638	-0.082
1639	-0.316
1640	0.093
1641	-0.968
1642	-0.5
1643	-0.629
1644	-0.637
1645	-0.76
1646	0.905
1647	1.74
1648	-0.483
1649	0.195
1650	-1.029
1651	1.053
1652	0.133
1653	-1.964
1654	-0.612
1655	-0.034
1656	1.234
1657	-0.385
1658	-0.913
1659	-0.704
1660	0.07
1661	1.283
1662	-0.777
1663	-2.266
1664	-1.645
1665	0.296
1666	-0.788
1667	-0.541
1668	0.192
1669	-0.706
1670	0.151
1671	1.451
1672	-0.384
1673	0.104
1674	0.001
1675	-0.633
1676	-1.025
1677	0.01
1678	0.326
1679	-0.318
1680	0.533
1681	0.245
1682	0.319
1683	0.35
1684	-0.032
1685	-1.538
1686	0.032
1687	0.346
1688	-0.384
1689	-0.022
1690	0.349
1691	0.07
1692	0.124
1693	0.089
1694	-0.561
1695	0.971
1696	-0.894
1697	-0.808
1698	0.304
1699	0.077
1700	-0.047
1701	0.275
1702	0.104
1703	0.329
1704	-1.503
1705	-1.172
1706	-0.528
1707	-0.954
1708	0.081
1709	0.09
1710	-0.298
1711	-0.1
1712	0.118
1713	-0.716
1714	-0.382
1715	-0.755
1716	-1.909
1717	-1.118
1718	0.217
1719	0.558
1720	1.125
1721	0.299
1722	-0.309
1723	0.374
1724	-0.727
1725	-2.273
1726	-1.544
1727	0.042
1728	-1.283
1729	0.026
1730	-1.018
1731	-1.377
1732	0.094
1733	-1.377
1734	0.072
1735	1.745
1736	0.628
1737	0.302
1738	0.81
1739	-0.602
1740	-0.219
1741	-0.922
1742	-2.962
1743	-1.354
1744	-0.547
1745	0.945
1746	0.478
1747	2.191
1748	0.018
1749	-0.163
1750	-1.269
1751	0.352
1752	-1.383
1753	-0.712
1754	-0.726
1755	-1.345
1756	-0.125
1757	-0.8
1758	-0.556
1759	1.613
1760	-0.602
1761	0.114
1762	0.138
1763	-0.74
1764	0.97
1765	-0.51
1766	0.675
1767	-0.466
1768	-0.525
1769	0.75
1770	0.767
1771	1.188
1772	-0.402
1773	-0.255
1774	0.244
1775	-1.972
1776	-0.829
1777	-0.065
1778	-1.12
1779	-0.425
1780	-0.548
1781	-0.781
1782	-0.627
1783	1.573
1784	-0.808
1785	-1.788
1786	-1.723
1787	-0.553
1788	-0.44
1789	-0.613
1790	-2.271
1791	0.197
1792	1.395
1793	0.652
1794	0.014
1795	0.069
1796	-0.161
1797	-0.959
1798	-0.952
1799	0.323
1800	1.052
1801	-1.466
1802	-2.062
1803	-0.074
1804	1.906
1805	-0.847
1806	-2.394
1807	-0.904
1808	-1.16
1809	-1.036
1810	-2.136
1811	-0.117
1812	0.025
1813	-0.055
1814	0.827
1815	-1.061
1816	0.349
1817	0.273
1818	-0.383
1819	-0.58
1820	-1.169
1821	0.154
1822	0.439
1823	0.285
1824	0.673
1825	1.297
1826	-0.117
1827	-0.346
1828	0.716
1829	-0.824
1830	-1.15
1831	-1.517
1832	-0.168
1833	0.526
1834	0.722
1835	-0.82
1836	-0.785
1837	0.009
1838	0.238
1839	0.658
1840	0.813
1841	0.385
1842	-0.155
1843	0.618
1844	0.595
1845	0.538
1846	0.775
1847	-0.912
1848	-0.439
1849	-0.327
1850	-0.318
1851	0.001
1852	-0.152
1853	0.415
1854	0.183
1855	-0.913
1856	0.568
1857	-0.735
1858	-0.625
1859	-0.143
1860	-0.135
1861	-1.4
1862	-2.104
1863	-1.064
1864	-1.473
1865	0.454
1866	0.46
1867	0.09
1868	-0.516
1869	2.413
1870	-0.07
1871	-2.095
1872	-0.792
1873	-0.789
1874	-0.439
1875	-1.087
1876	-0.078
1877	-0.453
1878	2.504
1879	-0.769
1880	-1.809
1881	-1.042
1882	-0.503
1883	-0.646
1884	-0.388
1885	0.191
1886	1.005
1887	-0.896
1888	0.109
1889	1.872
1890	-0.611
1891	-1.212
1892	-0.353
1893	-2.193
1894	-1.192
1895	-1.174
1896	0.024
1897	1.288
1898	-0.05
1899	-1.838
1900	0.152
1901	0.376
1902	-1.401
1903	0.689
1904	-0.549
1905	0.725
1906	0.757
1907	-0.269
1908	0.426
1909	-1.464
1910	-0.787
1911	-1.628
1912	0.353
1913	-0.149
1914	1.646
1915	0.904
1916	-0.907
1917	-3.724
1918	-2.315
1919	1.305
1920	1.855
1921	0.562
1922	-0.656
1923	-0.281
1924	0.107
1925	-1.416
1926	1.021
1927	-0.268
1928	-1.062
1929	-1.541
1930	0.041
1931	1.954
1932	-0.198
1933	-0.873
1934	-1.257
1935	-0.042
1936	-0.296
1937	0.18
1938	-0.357
1939	-1.244
1940	-1.207
1941	0.633
1942	-0.136
1943	-1.579
1944	-1.632
1945	0.314
1946	-0.672
1947	0.122
1948	-0.584
1949	-0.687
1950	-0.51
1951	-1.265
1952	1.027
1953	-1.263
1954	-1.202
1955	-0.755
1956	-1.75
1957	-1.403
1958	1.441
1959	0.454
1960	-0.516
1961	-1.045
1962	-1.159
1963	-1.765
1964	1.472
1965	-1.609
1966	0.422
1967	-1.018
1968	-0.912
1969	0.528
1970	-0.177
1971	-2.883
1972	-1.19
1973	1.629
1974	-1.55
1975	-0.173
1976	-1.676
1977	0.121
1978	0.72
1979	1.22
1980	0.233
1981	0.81
1982	-0.2
1983	1.367
1984	-0.469
1985	-0.716
1986	-0.467
1987	1.768
1988	1.622
1989	-0.987
1990	-1.024
1991	0.071
1992	2.361
1993	2.296
1994	0.482
1995	-1.202
1996	-1.373
1997	-0.957
1998	1.623
1999	-0.475
2000	-0.982
2001	-1.011
2002	0.546
2003	1.782
2004	0.61
2005	0.564
