Pacific and Indian Ocean climate signals in a tree‐ring record of Java monsoon drought

Abstract

Extreme climate conditions have dramatic socio-economic impacts on human populations across the tropics. In Indonesia, severe drought and floods have been associated with El Niño-Southern Oscillation (ENSO) events that originate in the tropical Indo-Pacific region. Recently, an Indian Ocean dipole mode (IOD) in sea surface temperature (SST) has been proposed as another potential cause of drought and flood extremes in western Indonesia and elsewhere around the Indian Ocean rim. The nature of such variability and its degree of independence from the ENSO system are topics of recent debate, but understanding is hampered by the scarcity of long instrumental records for the tropics. Here, we describe a tree-ring reconstruction of the Palmer Drought Severity Index (PDSI) for Java, Indonesia, that preserves a history of ENSO and IOD-related extremes over the past 217 years. Extreme Javan droughts correspond well to known ENSO and IOD events in recent decades, and most extreme droughts before this recent period can be explained by known ENSO episodes. Coral proxies from regions near or within the two poles of the IOD show good agreement with Javan PDSI extremes over the past ∼150 years. The El Niño of 1877, in conjunction with a positive IOD, was one of the most intense and widespread episodes of the past two centuries, based on instrumental and proxy data from across the tropical Indo-Pacific and Asian monsoon regions. Although Java droughts typically show the expected association with El Niño-like conditions and failed Indian monsoons, others (mainly linked to positive IOD conditions) co-occur with a strengthened Indian monsoon, suggesting linkages between the Indian monsoon, Indonesian drought and Indian Ocean climatic variability. The close associations between the Java PDSI, ENSO and Indian Ocean climate are consistent with the hypothesis that interannual ENSO to decadal ENSO-like modes interact to generate dipole-like Indian Ocean variability.

State of the Climate in 2008

“…2.23b to dynamical teleconnections from the Indo-Pacific region to higher latitudes in both hemispheres. There are also protracted El Niño and La Niña episodes, such as the protracted El Niño in the first half of the 1990s and the protracted La Niña from 1998 to 2000 (Allan and D'Arrigo 1999;D'Arrigo et al 2008). Such episodes are characterized by periods with weak-moderate anomalies, but their persistence over several years has substantial impacts.…”

Tree ring-based winter temperature reconstruction for Changting, Fujian, subtropical region of Southeast China, since 1850: linkages to the Pacific Ocean

“…Dendroclimatic studies in Thailand include research on teak (Tectona grandis) by Pumijurnnong et al (1995) and on mountain pine by Buckley et al (1995). Elsewhere in southeast Asia, tree-ring studies have been conducted in Indonesia (Berlage 1931;Jacoby and D'Arrigo 1990;D'Arrigo et al 1994;Poussart et al 2004;D'Arrigo et al 2006b;Buckley et al 2007a;D'Arrigo et al 2008D'Arrigo et al , 2011, Laos (Buckley et al 2007b), Malaysia and Vietnam (Sano et al 2009). The 700-year history of the Asian monsoon was reconstructed based on tree rings by Cook et al (2010).…”

Reconstruction of pre-monsoon weather conditions in northwestern Thailand from the tree-ring widths of Pinus merkusii and Pinus kesiya

“…The lack of instrumental climate data should be filled by proxy data such as tree-ring widths (Bhattacharyya and Yadav 1999;Borgaonkar et al 2010;Buckley et al 2007a;D'Arrigo et al 2008a), stalagmites (Maungsong 2010;Partin 2008), or corals (D'Arrigo et al 2008b). However, due to the complex climate phenomena in equatorial regions, the results from such proxy records are still ambiguous.…”

“…But it is unclear whether the El Niño-Southern Oscillation (ENSO) or the Indian Ocean Dipole (IOD) primarily affects this climate process (D'Arrigo et al 2008a). Due to the scarcity of instrumental climate records, trends in monsoon variability possibly resulting from global warming (IPCC 2007) cannot reliably be detected.…”