NOAA/WDS Paleoclimatology - Braganza et al. 2009 Multiproxy ENSO Reconstructions

An understanding of past variability in the El Niño–Southern Oscillation (ENSO), on interannual, interdecadal, and longer time scales, would be useful in assessing recent observed changes to ENSO and in determining the realism of climate model simulations. Using tree ring, coral, and ice core data, we reconstruct a proxy-based ENSO index between A.D. 1525 and 1982. Unlike most previous studies, which have drawn climate proxies from limited geographic regions, our network is Pacific basin–wide, using ENSO sensitive proxies from the western equatorial Pacific, New Zealand, the central Pacific, and subtropical North America. By considering multiple teleconnection regions, this network provides a more robust proxy ENSO signal. The common signal recorded in the multiproxy network has a high correlation with the Southern Oscillation Index (SOI), Niño 3.4 sea surface temperature (Niño3.4 SST), and a combined ocean-atmosphere ENSO index (CEI). The proportion of instrumental variance explained is 47% for the SOI, 48% for Niño3.4 SST, and 52% for the CEI. The proxy ENSO index also displays skill in reproducing warm and cold extremes of the SOI. The proxy ENSO index over the last 450 years shows considerable amplitude and frequency modulation in the 3–10 year band on multidecadal time scales. There is a relative reduction in the amplitude of high-frequency variability during the sixteenth, early seventeenth, and mid–eighteenth centuries. In contrast, high-frequency ENSO variability has increased over the last 200 years. Variability during the first half of the twentieth century is similar to that evident in the nineteenth century.

本存档古气候学（Paleoclimatology）研究可通过世界数据服务（WDS）古气候学分部，从美国国家海洋和大气管理局（NOAA）国家环境信息中心（NCEI）获取。该研究对应的NCEI类型为气候重建（Climate Reconstruction）。数据包含气候重建、冰芯（ice cores）、树轮（tree ring）等参数，地理定位为太平洋。时间覆盖范围为距今（BP，calendar years before present）的日历年份425年至-32年。有关参数和研究地点的详细信息，请参阅元数据（metadata）。使用数据时请引用本研究。