Suchergebnisse

The value of historic observational weather data for reconstructing long-term climate patterns and the detailed analysis of extreme weather events has long been recognized (Le Roy Ladurie, 1972; Lamb, 1977). In some regions however, observational data has not been kept regularly over time, or its preservation and archiving has not been considered a priority by governmental agencies. This has been a particular problem in Southeast Asia where there has been no systematic country-by-country method of keeping or preserving such data, the keeping of data only reaches back a few decades, or where instability has threatened the survival of historic records. As a result, past observational data are fragmentary, scattered, or even absent altogether. The further we go back in time, the more obvious the gaps. Observational data can be complimented however by historical documentary or proxy records of extreme events such as floods, droughts and other climatic anomalies. This review article highlights recent initiatives in sourcing, recovering, and preserving historical weather data and the potential for integrating the same with proxy (and other) records. In so doing, it focuses on regional initiatives for data research and recovery – particularly the work of the international Atmospheric Circulation Reconstructions over the Earth's (ACRE) Southeast Asian regional arm (ACRE SEA) – and the latter's role in bringing together disparate, but interrelated, projects working within this region. The overarching goal of the ACRE SEA initiative is to connect regional efforts and to build capacity within Southeast Asian institutions, agencies and National Meteorological and Hydrological Services (NMHS) to improve and extend historical instrumental, documentary and proxy databases of Southeast Asian hydroclimate, in order to contribute to the generation of high-quality, high-resolution historical hydroclimatic reconstructions (reanalyses) and, to build linkages with humanities researchers working on issues in environmental and climatic history in the region. Thus, this article also highlights the inherent value of multi/cross/inter-disciplinary projects in providing better syntheses and understanding of human and environmental/climatic variability and change.

Abstract
A "protracted" El Niño episode occurred from March–April 2018 to April–May 2020. It was manifested by the interlinked Indo-Pacific influences of two components of El Niño phases. Positive Indian Ocean dipoles (IODs) in 2018 and 2019 suppressed the formation of northwest cloud bands and southern Australia rainfall, and a persistent teleconnection, with enhanced convection generated by positive Niño-4 region sea surface temperature (SST) anomalies and strong subsidence over eastern Australia, exacerbated this Australian drought. As with "classical" El Niño–Southern Oscillation (ENSO) events, which usually last 12–18 months, protracted ENSO episodes, which last for more than 2 yr, show a similar pattern of impacts on society and the environment across the Indo-Pacific domain, and often extend globally. The second half of this study puts the impact of the 2018–20 protracted El Niño episode on both the Australian terrestrial agricultural and marine ecophysiological environments in a broader context. These impacts are often modulated not only by the direct effects of ENSO events and episodes, but by interrelated local to region ocean–atmosphere interactions and synoptic weather patterns. Even though the indices of protracted ENSO episodes are often weaker in magnitude than those of major classical ENSO events, it is the longer duration of the former that poses its own set of problems. Thus, there is an urgent need to investigate the potential to forecast protracted ENSO episodes, particularly when the mid-2020 to current 2022 period has been experiencing a major protracted La Niña episode with near-global impacts.

Significance Statement
The major 2018–20 Australian drought and its terrestrial and marine impacts were caused by a "protracted" El Niño episode, exacerbated by global warming. Indo-Pacific ocean–atmosphere interactions resulted in a persistent positive western Pacific Niño-4 sea surface temperature anomaly during the period 2018–20 and positive Indian Ocean dipoles (IODs) in 2018 and 2019. These suppressed rainfall across eastern Australia and limited northwest Australian cloud band rainfall across southern Australia. Australian agricultural and ecophysiological impacts caused by protracted El Niño–Southern Oscillation (ENSO) episodes permeate, overstress, and expose society, infrastructure, and livelihoods to longer temporal-scale pressures than those experienced during shorter "classical" ENSO events. Thus, there is an urgent need to investigate the potential to forecast protracted ENSO episodes.

Abstract The value of historic observational weather data for reconstructing long-term climate patterns and the detailed analysis of extreme weather events has long been recognized (Le Roy Ladurie, 1972; Lamb, 1977). In some regions however, observational data has not been kept regularly over time, or its preservation and archiving has not been considered a priority by governmental agencies. This has been a particular problem in Southeast Asia where there has been no systematic country-by-country method of keeping or preserving such data, the keeping of data only reaches back a few decades, or where instability has threatened the survival of historic records. As a result, past observational data are fragmentary, scattered, or even absent altogether. The further we go back in time, the more obvious the gaps. Observational data can be complimented however by historical documentary or proxy records of extreme events such as floods, droughts and other climatic anomalies. This review article highlights recent initiatives in sourcing, recovering, and preserving historical weather data and the potential for integrating the same with proxy (and other) records. In so doing, it focuses on regional initiatives for data research and recovery – particularly the work of the international Atmospheric Circulation Reconstructions over the Earth's (ACRE) Southeast Asian regional arm (ACRE SEA) – and the latter's role in bringing together disparate, but interrelated, projects working within this region. The overarching goal of the ACRE SEA initiative is to connect regional efforts and to build capacity within Southeast Asian institutions, agencies and National Meteorological and Hydrological Services (NMHS) to improve and extend historical instrumental, documentary and proxy databases of Southeast Asian hydroclimate, in order to contribute to the generation of high-quality, high-resolution historical hydroclimatic reconstructions (reanalyses) and, to build linkages with humanities researchers working on issues in environmental and climatic history in the region. Thus, this article also highlights the inherent value of multi/cross/inter-disciplinary projects in providing better syntheses and understanding of human and environmental/climatic variability and change.

The value of historic observational weather data for reconstructing long-term climate patterns and the detailed analysis of extreme weather events has long been recognized (Le Roy Ladurie, 1972; Lamb, 1977). In some regions however, observational data has not been kept regularly over time, or its preservation and archiving has not been considered a priority by governmental agencies. This has been a particular problem in Southeast Asia where there has been no systematic country-by-country method of keeping or preserving such data, the keeping of data only reaches back a few decades, or where instability has threatened the survival of historic records. As a result, past observational data are fragmentary, scattered, or even absent altogether. The further we go back in time, the more obvious the gaps. Observational data can be complimented however by historical documentary or proxy records of extreme events such as floods, droughts and other climatic anomalies. This review article highlights recent initiatives in sourcing, recovering, and preserving historical weather data and the potential for integrating the same with proxy (and other) records. In so doing, it focuses on regional initiatives for data research and recovery – particularly the work of the international Atmospheric Circulation Reconstructions over the Earth's (ACRE) Southeast Asian regional arm (ACRE SEA) – and the latter's role in bringing together disparate, but interrelated, projects working within this region. The overarching goal of the ACRE SEA initiative is to connect regional efforts and to build capacity within Southeast Asian institutions, agencies and National Meteorological and Hydrological Services (NMHS) to improve and extend historical instrumental, documentary and proxy databases of Southeast Asian hydroclimate, in order to contribute to the generation of high-quality, high-resolution historical hydroclimatic reconstructions (reanalyses) and, to build linkages with humanities researchers working on issues in environmental and climatic history in the region. Thus, this article also highlights the inherent value of multi/cross/inter-disciplinary projects in providing better syntheses and understanding of human and environmental/climatic variability and change.