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August 2013 - August 2015
August 2003 - July 2013
February 1997 - February 2003
Publications
Publications (145)
Atmospheric rivers play an integral role in the global water cycle, but predicting their future changes remains uncertain due to inter-model and inter-detection-method differences. Using ultra-high-resolution Community Earth System Model simulations and a novel detection algorithm based on geometric shape extraction, we quantify global changes in a...
In every IPCC Assessment cycle, a multitude of scenarios are assessed, with different scope and emphasis throughout the various Working Group and Special Reports and their respective chapters. Within the reports, the ambition is to integrate knowledge on possible climate futures across the Working Groups and scientific research domains based on a s...
“Decadal influence” on the El Niño–Southern Oscillation‐Indian summer monsoon teleconnection has been much studied but with plurality and ambiguity about the concept of influence. Here (a) we provide formal definitions of the apparent influence of a specific factor on the teleconnection, as correlation coefficients, which enable us to test them as...
Intergovernmental Panel on Climate Change (IPCC) assessments are the trusted source of scientific evidence for climate negotiations taking place under the United Nations Framework Convention on Climate Change (UNFCCC), including the first global stocktake under the Paris Agreement that will conclude at COP28 in December 2023. Evidence-based decisio...
This study describes a generalized framework, Scalable Feature Extraction and Tracking (SCAFET) to extract and track features from large climate datasets. SCAFET utilizes novel shape-based metrics that can efficiently identify and compare features from different mean states, datasets, and between distinct regions. Features of interest are extracted...
Intergovernmental Panel on Climate Change (IPCC) assessments are the trusted source of scientific evidence for climate negotiations taking place under the United Nations Framework Convention on Climate Change (UNFCCC), including the first global stocktake under the Paris Agreement that will conclude at COP28 in December 2023. Evidence-based decisio...
The IPCC AR6 Synthesis Report is based on the three Working Group contributions to the AR6 as well as on the three Special Reports prepared in this assessment cycle.
The global carbon cycle is strongly influenced by terrestrial productivity and ocean plankton concentration in the upper ocean1-4, with some carbon being transported from land to the ocean by chemical processes 5-9 and possibly returned to the atmosphere. High-latitude Ocean plankton may contribute to rapid surface warming, which could remotely aff...
Climate-forced, offline ice-sheet model simulations have been used extensively in assessing how much ice-sheets can contribute to future global sea-level rise. Typically, these model projections do not account for the two-way interactions between ice-sheets and climate. To quantify the impact of ice-ocean-atmosphere feedbacks, here we conduct green...
The rare extreme flooding event in Henan Province, China, during July 2021 (referred to as the “21.7” flooding event) was attributable to persistent heavy rainfall boosted by an enhanced moist southeasterly flow and substantial moisture convergence. Based on analyses of the scale-decomposed moisture budget equation, we show that the 21.7 flooding e...
Midlatitude stationary waves are relatively persistent large-scale longitudinal variations in atmospheric circulation. Although recent case studies have suggested a close connection between stationary waves and extreme weather events, little is known about the global-scale linkage between stationary waves and wildfire activity, as well as the poten...
The World Climate Research Programme (WCRP) envisions a world “that uses sound, relevant, and timely climate science to ensure a more resilient present and sustainable future for humankind.” This bold vision requires the climate science community to provide actionable scientific information that meets the evolving needs of societies all over the wo...
Current climate models still have considerable biases in the simulation of the East Asian summer monsoon (EASM), which in turn reduces their reliability of monsoon projections under global warming. We hypothesize that a higher-resolution coupled climate model with atmospheric and oceanic components at horizontal resolutions of 0.25° and 0.1°, respe...
“Decadal influence” on the El Nino–Southern Oscillation-Indian summer monsoon (ENSO-ISM) teleconnection has been much studied but with plurality and ambiguity about the concept of influence. Here we provide formal definitions of the apparent influence of a specific factor which enable us to test them as null-hypotheses. Using the recently released...
“Decadal influence” on the El Nin ̃o–Southern Oscillation-Indian summer monsoon (ENSO-ISM) teleconnection has been much studied but with plurality and ambiguity about the concept of influence. Here we provide formal definitions of the apparent influence of a specific factor on the teleconnection, as correlation coefficients, which enable us to test...
Plain Language Summary
In boreal summer, convective activity over the western Pacific on the intraseasonal time scale is primarily located to the north of the equator and exhibits characteristics of propagating northward. The northward propagation of convective activity can modulate the subtropical variability and typhoon activity and has significa...
Over the past half a century, both the Indian Ocean (IO) and the North Atlantic Ocean (NA) exhibit strong warming trends like a global mean surface temperature (SST). Here, we show that not only simply as a result of increased greenhouse gases, but the IO-NA interaction through atmospheric teleconnection boosts up their warming trends. Climate mode...
In many regions the projected future sea surface temperature (SST) response to greenhouse warming is larger in summer than in winter. What causes this amplification of the SST seasonal cycle has remained unclear. To determine robustness of the projected seasonal cycle intensification and ascertain underlying physical mechanisms we analyze a suite o...
Plain Language Summary
The variability of far separated regions can be correlated, teleconnected, which can give rise to seasonal predictability. Teleconnections can also undergo forced changes under external influence. These changes are not perfectly reflected in observed time series because of systematic errors, biases, of the estimates of correl...
Understanding heavy fire activities tied up to climate and its future change is of emerging scientific concern and essential for reducing huge economic costs and life losses from substantial heavy fire hazards under greenhouse warming. Madden-Julian Oscillation (MJO) is a planetary-scale tropical convective system and moves from Asia to the US, gen...
The COVID-19 pandemic caused disruptions of public life and imposed lockdown measures in 2020 resulted in considerable reductions of anthropogenic aerosol emissions. It still remains unclear how the associated short-term changes in atmospheric chemistry influenced weather and climate on regional scales. To understand the underlying physical mechani...
The Working Group I (WGI) contribution to the Intergovernmental Panel on Climate Change Sixth Assessment Report (AR6) assess the physical science basis of climate change. As part of that contribution,
this Technical Summary (TS) is designed to bridge between the comprehensive assessment of the WGI Chapters and its Summary for Policymakers (SPM). I...
This Annex describes the fundamental features of the main modes of large-scale climate variability assessed across chapters in the AR6 WGI report. Modes are defined as recurrent space-time structures of variability of the climate system with intrinsic spatial patterns, seasonality and timescales. They can arise through the dynamical characteristics...
A monsoon refers to a seasonal transition of regimes in atmospheric circulation and precipitation in response to the annual cycle of solar insolation and the distribution of moist static energy (Wang and Ding, 2008; Wang et al., 2014; Biasutti et al., 2018). A global monsoon can be objectively identified based on precipitation contrasts in the sols...
A correction to this paper has been published: https://doi.org/10.1007/s00382-021-05775-z
While West Antarctica has experienced the most significant warming in the world, a profound cooling trend in austral summer was observed over East Antarctica (30°W to 150°E, 70° to 90°S) from 1979 to 2014. Previous studies attributed these changes to high-latitude atmospheric dynamics, stratospheric ozone change, and tropical sea surface temperatur...
We study the forced response of the teleconnection between the El Niño–Southern Oscillation (ENSO) and the Indian summer monsoon (IM) in the Max Planck Institute Grand Ensemble, a set of Earth system ensemble simulations under historical and Representative Concentration Pathway (RCP) forcing. The forced response of the teleconnection, or a characte...
Intensification of El Niño-Southern Oscillation (ENSO)-rainfall variability in response to global warming is a robust feature across Coupled Model Intercomparison Project (CMIP) iterations, regardless of a lack of robust projected changes in ENSO-sea-surface temperature (SST) variability. Previous studies attributed this intensification to an incre...
Recent work has identified potential multi-year predictability in soil moisture (Chikamoto et al. in Clim Dyn 45(7–8):2213–2235, 2015). Whether this long-term predictability translates into an extended predictability of runoff still remains an open question. To address this question we develop a physically-based zero-dimensional stochastical dynami...
Coupled ocean-atmosphere teleconnections are characteristics of internal variability which have a forced response just like mean states. It is not trivial how to correctly and optimally estimate the forced response and changes of the El Niño-Southern Oscillation (ENSO)–Indian summer monsoon (ISM) teleconnection under greenhouse gas forcing. Here we...
The Working Group I (WGI) contribution to the Intergovernmental Panel on Climate Change Sixth Assessment Report (AR6) assess the physical science basis of climate change. As part of that contribution, this Technical Summary (TS) is designed to bridge between the comprehensive assessment of the WGI Chapters and its Summary for Policymakers (SPM). It...
Plain Language Summary
A heavy rainfall system propagates slowly from the equatorial western Pacific to the south China Sea and north of the Philippine Sea on a 20–70‐day time scale. This rainfall system affects the onset of East Asia monsoon and extreme weather including typhoons. Therefore, a better understanding of the dominant processes of the...
We study the forced response of the teleconnection between the El Nino-Southern Oscillation (ENSO) and global precipitation in general and the Indian summer monsoon (IM) in particular in the Max Planck Institute Grand Ensemble. The forced response of the teleconnection is defined as the time-dependence of a correlation coefficient evaluated over th...
The role of the Indian Ocean sea surface temperature (SST) in the rapid phase transition of the El Niño–Southern Oscillation (ENSO) has received much attention over the last few decades. However, the distinctive role of the Indian Ocean Dipole (IOD) and its underlying dynamics in controlling the rapid transition remains debatable, since it is diffi...
This paper reviews the current knowledge on detection, attribution and projection of global and regional monsoons (South Asian, East Asian, Australian, South American, North American, and African) under climate change.
Monsoon rainfall has profound economic and societal impacts for more than two-thirds of the global population. Here we provide a r...
Correspondence should be addressed to: timmermann@pusan.ac.kr The COVID-19 pandemic has led to massive disruptions of public life on a global scale. To halt the spread of the disease, China temporarily shut down parts of the manufacturing and transportation sectors. Associated anthropogenic aerosol emissions in February 2020 plunged to record lows,...
It has been widely known that the pulse of the western North Pacific anticyclonic circulation (WNPAC) plays a key role on East Asian summer climate variability in subseasonal to interannual time scales. Yet, the relation between the WNPAC and summer precipitation over Korea is not robust on seasonal and subseasonal timescales for the recent few dec...
The Tibetan Plateau (TP) and Himalayas have been treated as an essential external factor in shaping Asian monsoon and mid-latitude atmospheric circulation. In this study we perform numerical experiments with different uplift altitudes using the Nanjing University of Information Science and Technology Earth System Model to examine potential impacts...
The El Niño-Southern Oscillation (ENSO) events of recent decades have been divided into the two different types based on their spatial patterns, the Eastern Pacific (EP) type and Central Pacific (CP) type. Their most significant difference is the distinguished zonal center locations of sea surface temperature (SST) anomalies in the equatorial Pacif...
Northward propagation of the boreal summer intraseasonal oscillation (ISO) has profound impacts on Northern Hemisphere extreme weather events. This study aims to test the hypotheses proposed in the previous studies to explain northward propagation of the ISO by drastically changing the climatological mean states through lowering the Tibetan Plateau...
In this Review, the middle initial of author Kim M. Cobb was omitted. The original Review has been corrected online.
The relationship between the South Asia monsoon (SAM) and the East Asia monsoon (EAM) possibly modulated by both external forcings and internal dynamics has been a long-standing and controversial issue in climate sciences. This study reviews their linkages as revealed in modern records and model simulations during the past, present and future, and...
El Niño events are characterized by surface warming of the tropical Pacific Ocean and weakening of equatorial trade winds that occur every few years. Such conditions are accompanied by changes in atmospheric and oceanic circulation, affecting global climate, marine and terrestrial ecosystems, fisheries and human activities. The alternation of warm...
Multi-Model Ensembles (MMEs) are powerful tools in dynamical climate prediction as they account for the overconfidence and the uncertainties related to single-model ensembles. Previous works suggested that the potential benefit that can be expected by using a MME amplifies with the increase of the independence of the contributing Seasonal Predictio...
The East Asian Summer Monsoon driven by temperature and moisture gradients between the Asian continent and the Pacific Ocean, leads to approximately 50% of the annual rainfall in the region across 20-40°N. Due to its increasing scientific and social importance, there have been several previous studies on identification of moisture sources for summe...
This study examines the performances of 31 global climate models in the Coupled Model Inter-comparison Project 5 (CMIP5) in terms of probability density functions (PDFs) for maximum (Tmax) and minimum (Tmin) air temperatures over East Asia in the present and CMIP5-model projected future changes. In general, most of models well reproduce warm-season...
By analyzing observation-based high-resolution surface air temperature (SAT) data over the Asian monsoon region (here called "monsoon Asia") for 1981-2007, the modulation by boreal summer intraseasonal oscillation (BSISO) of heat wave (HW) occurrence is examined. Strong SAT variability and a high probability of HW occurrence on intraseasonal time s...
Changma, which is a vital part of East Asian summer monsoon (EASM) system, plays a critical role in modulating water and energy cycles in Korea. Better understanding of its long-term variability and change is therefore a matter of scientific and societal importance. It has been indicated that characteristics of Changma have undergone significant in...
This study develops an empirical orthogonal function (EOF)-based self-organizing map (SOM) (ESOM) analysis to identify the nonlinear characteristics of the boreal summer intraseasonal oscillation (BSISO), which involves interactions between the summer mean circulation and the convectively coupled equatorial waves, which make BSISO evolution more co...
The progress and current status of prediction activities on the Madden-Julian Oscillation (MJO) are reviewed. We have witnessed the significant progress in dynamical MJO prediction from 7-day limit using the (NCEP)-1 reanalysis vintage model during 1990s to about 30-day limit using the latest version of European Centre for Medium-Range Weather Fore...
Over the last few decades, there have been startling advances in our understanding of climate system and in modelling techniques. However, the skill of seasonal climate prediction is still not enough to meet the various needs from industrial and public sectors. Therefore, there are tremendous on-going efforts to improve the skill of climate predict...
The interaction of El Niño–Southern Oscillation (ENSO) with tropical Indian Ocean’s two major modes, i.e. Indian Ocean Dipole (IOD) and Indian Ocean basinwide mode (IOBM), is of great importance to understanding global climate variability. Using observational data for the last 50 years and the phase five of Coupled Model Intercomparison Project (CM...
A significant interdecadal change in the lagged relationship between the austral summer Pacific–South American (PSA) pattern and the El Niño–Southern Oscillation (ENSO) in the following austral summer (the PSA serving as a precursor signature to ENSO events) has been detected by analysis of a 91-year historical record. Strong correlations between t...
The Northern Hemisphere atmospheric blocking is a primary weather and climate system that accompanies extreme cold spells and heat waves. This study assesses effects of the Tibetan Plateau (TP), the largest continental mountain belt, on the blocking frequency (BF) and amplitude (BA) with progressive TP uplift experiments from 0 to 100 % using a cou...
Although the western North Pacific (WNP) monsoon circulation significantly impacts the socio-economic communities around Asia, its prediction is only limited to a few months. By examining the Coupled Model Inter-comparison Project phase 5 decadal hindcast experiments, we explore a possibility of the extended prediction skill for the WNP monsoon cir...