Articles | Volume 4, issue 4
https://doi.org/10.5194/wcd-4-1087-2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/wcd-4-1087-2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
07 Dec 2023
Research article |
| 07 Dec 2023
| 07 Dec 2023
Identifying quasi-periodic variability using multivariate empirical mode decomposition: a case of the tropical Pacific
Geophysical Institute, University of Bergen, Bergen, Norway
Bjerknes Centre for Climate Research, Bergen, Norway
Nour-Eddine Omrani
CORRESPONDING AUTHOR
Geophysical Institute, University of Bergen, Bergen, Norway
Bjerknes Centre for Climate Research, Bergen, Norway
Noel S. Keenlyside
Geophysical Institute, University of Bergen, Bergen, Norway
Bjerknes Centre for Climate Research, Bergen, Norway
Related authors
Matic Pikovnik, Žiga Zaplotnik, Lina Boljka, and Nedjeljka Žagar
Weather Clim. Dynam., 3, 625–644, https://doi.org/10.5194/wcd-3-625-2022, https://doi.org/10.5194/wcd-3-625-2022, 2022
Short summary
Short summary
Potential future changes in the Hadley cells (HCs), either to their strength or their meridional extent, will profoundly impact the global distribution of precipitation. Therefore, to objectively evaluate and inter-compare past and future changes in the overall HC strength between different studies, a unified metric is required. The study proposes two new metrics, which alleviate the spatial inhomogeneities of the HC strength trend.
Lina Boljka and Thomas Birner
Weather Clim. Dynam., 1, 555–575, https://doi.org/10.5194/wcd-1-555-2020, https://doi.org/10.5194/wcd-1-555-2020, 2020
Short summary
Short summary
This study addresses the origin and impacts of a source of large-scale atmospheric waves in the lower stratosphere, which have not been examined before. This wave source is caused by interactions of waves of smaller scales. Here we show that as it lies in the lower stratosphere, this wave source can precede extreme events in the stratosphere and that such events can then lead to a response of the tropospheric weather patterns several weeks later (potential for long-term forecasting).
Ingo Richter, Ping Chang, Gokhan Danabasoglu, Dietmar Dommenget, Guillaume Gastineau, Aixue Hu, Takahito Kataoka, Noel Keenlyside, Fred Kucharski, Yuko Okumura, Wonsun Park, Malte Stuecker, Andrea Taschetto, Chunzai Wang, Stephen Yeager, and Sang-Wook Yeh
EGUsphere, https://doi.org/10.5194/egusphere-2024-3110, https://doi.org/10.5194/egusphere-2024-3110, 2024
Short summary
Short summary
The tropical ocean basins influence each other through multiple pathways and mechanisms, here referred to as tropical basin interaction (TBI). Many researchers have examined TBI using comprehensive climate models, but have obtained conflicting results. This may be partly due to differences in experiment protocols, and partly due to systematic model errors. TBIMIP aims to address this problem by designing a set of TBI experiments that will be performed by multiple models.
William Eric Chapman, Francine Schevenhoven, Judith Berner, Noel Keenlyside, Ingo Bethke, Ping-Gin Chiu, Alok Gupta, and Jesse Nusbaumer
EGUsphere, https://doi.org/10.5194/egusphere-2024-2682, https://doi.org/10.5194/egusphere-2024-2682, 2024
Short summary
Short summary
We introduce the first state-of-the-art atmosphere-connected supermodel, where two advanced atmospheric models share information in real-time to form a new dynamical system. By synchronizing the models, particularly in storm track regions, we achieve better predictions without losing variability. This approach maintains key climate patterns and reduces bias in some variables compared to traditional models, demonstrating a useful technique for improving atmospheric simulations.
Shunya Koseki, Lander R. Crespo, Jerry Tjiputra, Filippa Fransner, Noel S. Keenlyside, and David Rivas
Biogeosciences, 21, 4149–4168, https://doi.org/10.5194/bg-21-4149-2024, https://doi.org/10.5194/bg-21-4149-2024, 2024
Short summary
Short summary
We investigated how the physical biases of an Earth system model influence the marine biogeochemical processes in the tropical Atlantic. With four different configurations of the model, we have shown that the versions with better SST reproduction tend to better represent the primary production and air–sea CO2 flux in terms of climatology, seasonal cycle, and response to climate variability.
Akhilesh Sivaraman Nair, François Counillon, and Noel Keenlyside
Geosci. Model Dev. Discuss., https://doi.org/10.5194/gmd-2023-217, https://doi.org/10.5194/gmd-2023-217, 2024
Publication in GMD not foreseen
Short summary
Short summary
This study demonstrates the importance of soil moisture (SM) in subseasonal-to-seasonal predictions. To addess this, we introduce the Norwegian Climate Prediction Model Land (NorCPM-Land), a land data assimilation system developed for the NorCPM. NorCPM-Land reduces error in SM by 10.5 % by assimilating satellite SM products. Enhanced land initialisation improves predictions up to a 3.5-month lead time for SM and a 1.5-month lead time for temperature and precipitation.
Matic Pikovnik, Žiga Zaplotnik, Lina Boljka, and Nedjeljka Žagar
Weather Clim. Dynam., 3, 625–644, https://doi.org/10.5194/wcd-3-625-2022, https://doi.org/10.5194/wcd-3-625-2022, 2022
Short summary
Short summary
Potential future changes in the Hadley cells (HCs), either to their strength or their meridional extent, will profoundly impact the global distribution of precipitation. Therefore, to objectively evaluate and inter-compare past and future changes in the overall HC strength between different studies, a unified metric is required. The study proposes two new metrics, which alleviate the spatial inhomogeneities of the HC strength trend.
Ingo Bethke, Yiguo Wang, François Counillon, Noel Keenlyside, Madlen Kimmritz, Filippa Fransner, Annette Samuelsen, Helene Langehaug, Lea Svendsen, Ping-Gin Chiu, Leilane Passos, Mats Bentsen, Chuncheng Guo, Alok Gupta, Jerry Tjiputra, Alf Kirkevåg, Dirk Olivié, Øyvind Seland, Julie Solsvik Vågane, Yuanchao Fan, and Tor Eldevik
Geosci. Model Dev., 14, 7073–7116, https://doi.org/10.5194/gmd-14-7073-2021, https://doi.org/10.5194/gmd-14-7073-2021, 2021
Short summary
Short summary
The Norwegian Climate Prediction Model version 1 (NorCPM1) is a new research tool for performing climate reanalyses and seasonal-to-decadal climate predictions. It adds data assimilation capability to the Norwegian Earth System Model version 1 (NorESM1) and has contributed output to the Decadal Climate Prediction Project (DCPP) as part of the sixth Coupled Model Intercomparison Project (CMIP6). We describe the system and evaluate its baseline, reanalysis and prediction performance.
Lina Boljka and Thomas Birner
Weather Clim. Dynam., 1, 555–575, https://doi.org/10.5194/wcd-1-555-2020, https://doi.org/10.5194/wcd-1-555-2020, 2020
Short summary
Short summary
This study addresses the origin and impacts of a source of large-scale atmospheric waves in the lower stratosphere, which have not been examined before. This wave source is caused by interactions of waves of smaller scales. Here we show that as it lies in the lower stratosphere, this wave source can precede extreme events in the stratosphere and that such events can then lead to a response of the tropospheric weather patterns several weeks later (potential for long-term forecasting).
Xiao-Yi Yang, Guihua Wang, and Noel Keenlyside
The Cryosphere, 14, 693–708, https://doi.org/10.5194/tc-14-693-2020, https://doi.org/10.5194/tc-14-693-2020, 2020
Short summary
Short summary
The post-2007 Arctic sea ice cover is characterized by a remarkable increase in annual cycle amplitude, which is attributed to multiyear variability in spring Bering sea ice extent. We demonstrated that changes of NPGO mode, by anomalous wind stress curl and Ekman pumping, trigger subsurface variability in the Bering basin. This accounts for the significant decadal oscillation of spring Bering sea ice after 2007. The study helps us to better understand the recent Arctic climate regime shift.
Francine Schevenhoven, Frank Selten, Alberto Carrassi, and Noel Keenlyside
Earth Syst. Dynam., 10, 789–807, https://doi.org/10.5194/esd-10-789-2019, https://doi.org/10.5194/esd-10-789-2019, 2019
Short summary
Short summary
Weather and climate predictions potentially improve by dynamically combining different models into a
supermodel. A crucial step is to train the supermodel on the basis of observations. Here, we apply two different training methods to the global atmosphere–ocean–land model SPEEDO. We demonstrate that both training methods yield climate and weather predictions of superior quality compared to the individual models. Supermodel predictions can also outperform the commonly used multi-model mean.
Jan Wohland, Nour Eddine Omrani, Noel Keenlyside, and Dirk Witthaut
Wind Energ. Sci., 4, 515–526, https://doi.org/10.5194/wes-4-515-2019, https://doi.org/10.5194/wes-4-515-2019, 2019
Short summary
Short summary
Wind park planning and power system design require robust wind resource information. While most assessments are restricted to the last four decades, we use centennial reanalyses to study wind energy generation variability in Germany. We find that statistically significant multi-decadal variability exists. These long-term effects must be considered when planning future highly renewable power systems. Otherwise, there is a risk of inefficient system design and ill-informed investments.
Sandro W. Lubis, Vered Silverman, Katja Matthes, Nili Harnik, Nour-Eddine Omrani, and Sebastian Wahl
Atmos. Chem. Phys., 17, 2437–2458, https://doi.org/10.5194/acp-17-2437-2017, https://doi.org/10.5194/acp-17-2437-2017, 2017
Short summary
Short summary
Downward wave coupling (DWC) events impact high-latitude stratospheric ozone in two ways: (1) reduced dynamical transport of ozone from low to high latitudes during individual events and (2) enhanced springtime chemical destruction of ozone via the cumulative impact of DWC events on polar stratospheric temperatures. The results presented here broaden the scope of the impact of wave–mean flow interaction on stratospheric ozone by highlighting the key role of wave reflection.
Related subject area
Dynamical processes in the tropics, incl. tropical–extratropical interactions
A simple model linking radiative–convective instability, convective aggregation and large-scale dynamics
Spatial and temporal variability of the freezing level in Patagonia's atmosphere
Tropical cyclone asymmetric eyewall evolution and intensification in a two-layer model
Role of the Quasi-Biennial Oscillation on Alleviating Biases in the Semi-Annual Oscillation
Changes in the tropical upper-tropospheric zonal momentum balance due to global warming
Using regional relaxation experiments to understand the development of errors in the Asian summer monsoon
WCD Ideas: Teleconnections through weather rather than stationary waves
Development of Indian summer monsoon precipitation biases in two seasonal forecasting systems and their response to large-scale drivers
Quantifying uncertainty in simulations of the West African monsoon with the use of surrogate models
Increasing frequency and lengthening season of western disturbances are linked to increasing strength and delayed northward migration of the subtropical jet
Sustained intensification of the Aleutian Low induces weak tropical Pacific sea surface warming
Multi-decadal pacemaker simulations with an intermediate-complexity climate model
Replicating the Hadley cell edge and subtropical jet latitude disconnect in idealized atmospheric models
Warm conveyor belt activity over the Pacific: modulation by the Madden–Julian Oscillation and impact on tropical–extratropical teleconnections
Understanding the dependence of mean precipitation on convective treatment and horizontal resolution in tropical aquachannel experiments
Examining the dynamics of a Borneo vortex using a balance approximation tool
Strengthening gradients in the tropical west Pacific connect to European summer temperatures on sub-seasonal timescales
Classification of large-scale environments that drive the formation of mesoscale convective systems over southern West Africa
Validation of boreal summer tropical–extratropical causal links in seasonal forecasts
Large uncertainty in observed estimates of tropical width from the meridional stream function
The impact of the Agulhas Current system on precipitation in southern Africa in regional climate simulations covering the recent past and future
Intensity fluctuations in Hurricane Irma (2017) during a period of rapid intensification
Investigation of links between dynamical scenarios and particularly high impact of Aeolus on numerical weather prediction (NWP) forecasts
Can low-resolution CMIP6 ScenarioMIP models provide insight into future European post-tropical-cyclone risk?
Non-linear intensification of monsoon low-pressure systems by the BSISO
Dynamics of gap winds in the Great Rift Valley, Ethiopia: emphasis on strong winds at Lake Abaya
Metrics of the Hadley circulation strength and associated circulation trends
Characterising the interaction of tropical and extratropical air masses controlling East Asian summer monsoon progression using a novel frontal detection approach
Extreme Atlantic hurricane seasons made twice as likely by ocean warming
Synoptic processes of winter precipitation in the Upper Indus Basin
Acceleration of tropical cyclones as a proxy for extratropical interactions: synoptic-scale patterns and long-term trends
Subtle influence of the Atlantic Meridional Overturning Circulation (AMOC) on seasonal sea surface temperature (SST) hindcast skill in the North Atlantic
Drivers of uncertainty in future projections of Madden–Julian Oscillation teleconnections
Zonal scale and temporal variability of the Asian monsoon anticyclone in an idealised numerical model
African easterly waves in an idealized general circulation model: instability and wave packet diagnostics
How Rossby wave breaking modulates the water cycle in the North Atlantic trade wind region
The effect of seasonally and spatially varying chlorophyll on Bay of Bengal surface ocean properties and the South Asian monsoon
Dominant patterns of interaction between the tropics and mid-latitudes in boreal summer: causal relationships and the role of timescales
Abrupt transitions in an atmospheric single-column model with weak temperature gradient approximation
The American monsoon system in HadGEM3 and UKESM1
Matthew Davison and Peter Haynes
Weather Clim. Dynam., 5, 1153–1185, https://doi.org/10.5194/wcd-5-1153-2024, https://doi.org/10.5194/wcd-5-1153-2024, 2024
Short summary
Short summary
A simple model is used to study the relation between small-scale convection and large-scale variability in the tropics arising from the coupling between moisture and dynamics. In the model, moisture preferentially lies at either moist or dry states, which merge to form large-scale aggregated regions. On an equatorial β plane, these aggregated regions are localised at the Equator and propagate zonally. This forms an intermediate model between past simpler models and general circulation models.
Nicolás García-Lee, Claudio Bravo, Álvaro Gónzalez-Reyes, and Piero Mardones
Weather Clim. Dynam., 5, 1137–1151, https://doi.org/10.5194/wcd-5-1137-2024, https://doi.org/10.5194/wcd-5-1137-2024, 2024
Short summary
Short summary
This study analyses the 0 °C isotherm in Patagonia from 1959 to 2021, using observational and fifth-generation European Centre for Medium-Range Weather Forecasts atmospheric reanalysis data. The model aligns well with observations, highlighting significant altitude variations between the western and eastern sides of the austral Andes, a correlation between isotherm fluctuations and the Southern Annular Mode index, and an upward trend in the study area (especially in northwestern Patagonia).
Ting-Yu Cha and Michael M. Bell
Weather Clim. Dynam., 5, 1013–1029, https://doi.org/10.5194/wcd-5-1013-2024, https://doi.org/10.5194/wcd-5-1013-2024, 2024
Short summary
Short summary
Our study investigates the dynamics of polygonal eyewall structures observed in intensifying hurricanes like Michael (2018) by using a simplified modeling approach. We develop a two-layer model to simulate the interactions between the free atmosphere and boundary layer to demonstrate the importance of different physical mechanisms in the intensification process. This simplified model offers insights into the interactions between dynamics and convection during hurricane intensification.
Aleena Moolakkunnel Jaison, Lesley J. Gray, Scott M. Osprey, Jeff R. Knight, and Martin B. Andrews
EGUsphere, https://doi.org/10.5194/egusphere-2024-1818, https://doi.org/10.5194/egusphere-2024-1818, 2024
Short summary
Short summary
Models have biases in SAO representation, primarily due to lack of strong enough eastward wave forcing. We investigated if this bias arises from increased wave absorption in low-mid stratosphere due to circulation biases. Using model experiments, we found that removing biases in lower altitudes improve the SAO, but a significant bias remains. Thus, modifications to gravity wave parametrisation is required to improve the modelled SAO, potentially leading to improved predictability of SSW.
Abu Bakar Siddiqui Thakur and Jai Sukhatme
Weather Clim. Dynam., 5, 839–862, https://doi.org/10.5194/wcd-5-839-2024, https://doi.org/10.5194/wcd-5-839-2024, 2024
Short summary
Short summary
We analyze the present and future states of the tropical upper troposphere. Observations and climate model simulations suggest that interactions between disparate families of waves and the mean flow maintain present-day upper-level winds, and each component undergoes complex changes due to global warming. While the net east–west flow of the atmosphere may remain unaltered, this study indicates robust changes to local circulations that may influence tropical precipitation and regional climate.
Gill M. Martin and José M. Rodríguez
Weather Clim. Dynam., 5, 711–731, https://doi.org/10.5194/wcd-5-711-2024, https://doi.org/10.5194/wcd-5-711-2024, 2024
Short summary
Short summary
Using sensitivity experiments, we show that model errors developing in the Maritime Continent region contribute substantially to the Asian summer monsoon (ASM) circulation and rainfall errors through their effects on the western North Pacific subtropical high-pressure region and the winds and sea surface temperatures in the equatorial Indian Ocean, exacerbated by local coupled feedback. Such information will inform future model developments aimed at improving model predictions for the ASM.
Clemens Spensberger
Weather Clim. Dynam., 5, 659–669, https://doi.org/10.5194/wcd-5-659-2024, https://doi.org/10.5194/wcd-5-659-2024, 2024
Short summary
Short summary
It is well-established that variations in convection in the tropical Indo-Pacific can influence weather in far-away regions. In this idea, I argue that the main theory used to explain this influence over large distances is incomplete. I propose hypotheses that could lead the way towards a more fundamental explanation and outline a novel approach that could be used to test the hypotheses I raise. The suggested approach might be useful to address also other long-standing questions.
Richard J. Keane, Ankur Srivastava, and Gill M. Martin
Weather Clim. Dynam., 5, 671–702, https://doi.org/10.5194/wcd-5-671-2024, https://doi.org/10.5194/wcd-5-671-2024, 2024
Short summary
Short summary
We evaluate the performance of two widely used models in forecasting the Indian summer monsoon, which is one of the most challenging meteorological phenomena to simulate. The work links previous studies evaluating the use of the models in weather forecasting and climate simulation, as the focus here is on seasonal forecasting, which involves intermediate timescales. As well as being important in itself, this evaluation provides insights into how errors develop in the two modelling systems.
Matthias Fischer, Peter Knippertz, Roderick van der Linden, Alexander Lemburg, Gregor Pante, Carsten Proppe, and John H. Marsham
Weather Clim. Dynam., 5, 511–536, https://doi.org/10.5194/wcd-5-511-2024, https://doi.org/10.5194/wcd-5-511-2024, 2024
Short summary
Short summary
Our research enhances the understanding of the complex dynamics within the West African monsoon system by analyzing the impact of specific model parameters on its characteristics. Employing surrogate models, we identified critical factors such as the entrainment rate and the fall velocity of ice. Precise definition of these parameters in weather models could improve forecast accuracy, thus enabling better strategies to manage and reduce the impact of weather events.
Kieran M. R. Hunt
Weather Clim. Dynam., 5, 345–356, https://doi.org/10.5194/wcd-5-345-2024, https://doi.org/10.5194/wcd-5-345-2024, 2024
Short summary
Short summary
This study investigates changes in weather systems that bring winter precipitation to south Asia. We find that these systems, known as western disturbances, are occurring more frequently and lasting longer into the summer months. This shift is leading to devastating floods, as happened recently in north India. By analysing 70 years of weather data, we trace this change to shifts in major air currents known as the subtropical jet. Due to climate change, such events are becoming more frequent.
William J. Dow, Christine M. McKenna, Manoj M. Joshi, Adam T. Blaker, Richard Rigby, and Amanda C. Maycock
Weather Clim. Dynam., 5, 357–367, https://doi.org/10.5194/wcd-5-357-2024, https://doi.org/10.5194/wcd-5-357-2024, 2024
Short summary
Short summary
Changes to sea surface temperatures in the extratropical North Pacific are driven partly by patterns of local atmospheric circulation, such as the Aleutian Low. We show that an intensification of the Aleutian Low could contribute to small changes in temperatures across the equatorial Pacific via the initiation of two mechanisms. The effect, although significant, is unlikely to explain fully the recently observed multi-year shift of a pattern of climate variability across the wider Pacific.
Franco Molteni, Fred Kucharski, and Riccardo Farneti
Weather Clim. Dynam., 5, 293–322, https://doi.org/10.5194/wcd-5-293-2024, https://doi.org/10.5194/wcd-5-293-2024, 2024
Short summary
Short summary
We describe some new features of an intermediate-complexity coupled model, including a three-layer thermodynamic ocean model suitable to explore the extratropical response to tropical ocean variability. We present results on the model climatology and show that important features of interdecadal and interannual variability are realistically simulated in a
pacemakercoupled ensemble of 70-year runs, where portions of the tropical Indo-Pacific are constrained to follow the observed variability.
Molly E. Menzel, Darryn W. Waugh, Zheng Wu, and Thomas Reichler
Weather Clim. Dynam., 5, 251–261, https://doi.org/10.5194/wcd-5-251-2024, https://doi.org/10.5194/wcd-5-251-2024, 2024
Short summary
Short summary
Recent work exploring the tropical atmospheric circulation response to climate change has revealed a disconnect in the latitudinal location of two features, the subtropical jet and the Hadley cell edge. Here, we investigate if the surprising result from coupled climate model and meteorological reanalysis output is consistent across model complexity.
Julian F. Quinting, Christian M. Grams, Edmund Kar-Man Chang, Stephan Pfahl, and Heini Wernli
Weather Clim. Dynam., 5, 65–85, https://doi.org/10.5194/wcd-5-65-2024, https://doi.org/10.5194/wcd-5-65-2024, 2024
Short summary
Short summary
Research in the last few decades has revealed that rapidly ascending airstreams in extratropical cyclones have an important effect on the evolution of downstream weather and predictability. In this study, we show that the occurrence of these airstreams over the North Pacific is modulated by tropical convection. Depending on the modulation, known atmospheric circulation patterns evolve quite differently, which may affect extended-range predictions in the Atlantic–European region.
Hyunju Jung, Peter Knippertz, Yvonne Ruckstuhl, Robert Redl, Tijana Janjic, and Corinna Hoose
Weather Clim. Dynam., 4, 1111–1134, https://doi.org/10.5194/wcd-4-1111-2023, https://doi.org/10.5194/wcd-4-1111-2023, 2023
Short summary
Short summary
A narrow rainfall belt in the tropics is an important feature for large-scale circulations and the global water cycle. The accurate simulation of this rainfall feature has been a long-standing problem, with the reasons behind that unclear. We present a novel diagnostic tool that allows us to disentangle processes important for rainfall, which changes due to modifications in model. Using our diagnostic tool, one can potentially identify sources of uncertainty in weather and climate models.
Sam Hardy, John Methven, Juliane Schwendike, Ben Harvey, and Mike Cullen
Weather Clim. Dynam., 4, 1019–1043, https://doi.org/10.5194/wcd-4-1019-2023, https://doi.org/10.5194/wcd-4-1019-2023, 2023
Short summary
Short summary
We examine a Borneo vortex case using computer simulations and satellite observations. The vortex is identified with high humidity through the atmosphere and has heaviest rainfall on its northern flank. Simulations represent circulation and rainfall accumulation well. The low-level Borneo vortex is coupled with a higher-level wave, which moves westwards along a layer with a sharp vertical gradient in moisture. Vortex growth occurs through mechanisms usually considered outside the tropics.
Chiem van Straaten, Dim Coumou, Kirien Whan, Bart van den Hurk, and Maurice Schmeits
Weather Clim. Dynam., 4, 887–903, https://doi.org/10.5194/wcd-4-887-2023, https://doi.org/10.5194/wcd-4-887-2023, 2023
Short summary
Short summary
Variability in the tropics can influence weather over Europe. This study evaluates a summertime connection between the two. It shows that strongly opposing west Pacific sea surface temperature anomalies have occurred more frequently since 1980, likely due to a combination of long-term warming in the west Pacific and the El Niño Southern Oscillation. Three to six weeks later, the distribution of hot and cold airmasses over Europe is affected.
Francis Nkrumah, Cornelia Klein, Kwesi Akumenyi Quagraine, Rebecca Berkoh-Oforiwaa, Nana Ama Browne Klutse, Patrick Essien, Gandomè Mayeul Leger Davy Quenum, and Hubert Azoda Koffi
Weather Clim. Dynam., 4, 773–788, https://doi.org/10.5194/wcd-4-773-2023, https://doi.org/10.5194/wcd-4-773-2023, 2023
Short summary
Short summary
It is not yet clear which variations in broader atmospheric conditions of the West African monsoon may lead to mesoscale convective system (MCS) occurrences in southern West Africa (SWA). In this study, we identified nine different weather patterns and categorized them as dry-, transition-, or monsoon-season types using a method called self-organizing maps (SOMs). It was revealed that a warmer Sahel region can create favourable conditions for MCS formation in SWA.
Giorgia Di Capua, Dim Coumou, Bart van den Hurk, Antje Weisheimer, Andrew G. Turner, and Reik V. Donner
Weather Clim. Dynam., 4, 701–723, https://doi.org/10.5194/wcd-4-701-2023, https://doi.org/10.5194/wcd-4-701-2023, 2023
Short summary
Short summary
Heavy rainfall in tropical regions interacts with mid-latitude circulation patterns, and this interaction can explain weather patterns in the Northern Hemisphere during summer. In this analysis we detect these tropical–extratropical interaction pattern both in observational datasets and data obtained by atmospheric models and assess how well atmospheric models can reproduce the observed patterns. We find a good agreement although these relationships are weaker in model data.
Daniel Baldassare, Thomas Reichler, Piret Plink-Björklund, and Jacob Slawson
Weather Clim. Dynam., 4, 531–541, https://doi.org/10.5194/wcd-4-531-2023, https://doi.org/10.5194/wcd-4-531-2023, 2023
Short summary
Short summary
Using ensemble members from the ERA5 reanalysis, the most widely used method for estimating tropical-width trends, the meridional stream function, was found to have large error, particularly in the Northern Hemisphere and in the summer, because of weak gradients at the tropical edge and poor data quality. Another method, using the latitude where the surface wind switches from westerly to easterly, was found to have lower error due to better-observed data.
Nele Tim, Eduardo Zorita, Birgit Hünicke, and Ioana Ivanciu
Weather Clim. Dynam., 4, 381–397, https://doi.org/10.5194/wcd-4-381-2023, https://doi.org/10.5194/wcd-4-381-2023, 2023
Short summary
Short summary
As stated by the IPCC, southern Africa is one of the two land regions that are projected to suffer from the strongest precipitation reductions in the future. Simulated drying in this region is linked to the adjacent oceans, and prevailing winds as warm and moist air masses are transported towards the continent. Precipitation trends in past and future climate can be partly attributed to the strength of the Agulhas Current system, the current along the east and south coasts of southern Africa.
William Torgerson, Juliane Schwendike, Andrew Ross, and Chris J. Short
Weather Clim. Dynam., 4, 331–359, https://doi.org/10.5194/wcd-4-331-2023, https://doi.org/10.5194/wcd-4-331-2023, 2023
Short summary
Short summary
We investigated intensity fluctuations that occurred during the rapid intensification of Hurricane Irma (2017) to understand their effects on the storm structure. Using high-resolution model simulations, we found that the fluctuations were caused by local regions of strong ascent just outside the eyewall that disrupted the storm, leading to a larger and more symmetrical storm eye. This alters the location and intensity of the strongest winds in the storm and hence the storm's impact.
Anne Martin, Martin Weissmann, and Alexander Cress
Weather Clim. Dynam., 4, 249–264, https://doi.org/10.5194/wcd-4-249-2023, https://doi.org/10.5194/wcd-4-249-2023, 2023
Short summary
Short summary
Global wind profiles from the Aeolus satellite mission are an important recent substitute for the Global Observing System, showing an overall positive impact on numerical weather prediction forecasts. This study highlights atmospheric dynamic phenomena constituting pathways for significant improvement of Aeolus for future studies, including large-scale tropical circulation systems and the interaction of tropical cyclones undergoing an extratropical transition with the midlatitude waveguide.
Elliott Michael Sainsbury, Reinhard K. H. Schiemann, Kevin I. Hodges, Alexander J. Baker, Len C. Shaffrey, Kieran T. Bhatia, and Stella Bourdin
Weather Clim. Dynam., 3, 1359–1379, https://doi.org/10.5194/wcd-3-1359-2022, https://doi.org/10.5194/wcd-3-1359-2022, 2022
Short summary
Short summary
Post-tropical cyclones (PTCs) can bring severe weather to Europe. By tracking and identifying PTCs in five global climate models, we investigate how the frequency and intensity of PTCs may change across Europe by 2100. We find no robust change in the frequency or intensity of Europe-impacting PTCs in the future. This study indicates that large uncertainties surround future Europe-impacting PTCs and provides a framework for evaluating PTCs in future generations of climate models.
Kieran M. R. Hunt and Andrew G. Turner
Weather Clim. Dynam., 3, 1341–1358, https://doi.org/10.5194/wcd-3-1341-2022, https://doi.org/10.5194/wcd-3-1341-2022, 2022
Short summary
Short summary
More than half of India's summer monsoon rainfall arises from low-pressure systems: storms originating over the Bay of Bengal. In observation-based data, we examine how the generation and pathway of these storms are changed by the
boreal summer intraseasonal oscillation– the chief means of large-scale control on the monsoon at timescales of a few weeks. Our study offers new insights for useful prediction of these storms, important for both water resources planning and disaster early warning.
Cornelius Immanuel Weiß, Alexander Gohm, Mathias Walter Rotach, and Thomas Torora Minda
Weather Clim. Dynam., 3, 1003–1019, https://doi.org/10.5194/wcd-3-1003-2022, https://doi.org/10.5194/wcd-3-1003-2022, 2022
Short summary
Short summary
Two gap flow events in the Great Rift Valley in Ethiopia were investigated based on observations, ERA5 reanalysis data, and simulations with the numerical weather prediction model WRF. The main focus was on strong winds in the area around Lake Abaya since the winds may generate waves on the lake which help to sustain the lake's ecology. That is important in terms of food supply for the local population. The gap winds exhibit a diurnal cycle and a seasonal dependence.
Matic Pikovnik, Žiga Zaplotnik, Lina Boljka, and Nedjeljka Žagar
Weather Clim. Dynam., 3, 625–644, https://doi.org/10.5194/wcd-3-625-2022, https://doi.org/10.5194/wcd-3-625-2022, 2022
Short summary
Short summary
Potential future changes in the Hadley cells (HCs), either to their strength or their meridional extent, will profoundly impact the global distribution of precipitation. Therefore, to objectively evaluate and inter-compare past and future changes in the overall HC strength between different studies, a unified metric is required. The study proposes two new metrics, which alleviate the spatial inhomogeneities of the HC strength trend.
Ambrogio Volonté, Andrew G. Turner, Reinhard Schiemann, Pier Luigi Vidale, and Nicholas P. Klingaman
Weather Clim. Dynam., 3, 575–599, https://doi.org/10.5194/wcd-3-575-2022, https://doi.org/10.5194/wcd-3-575-2022, 2022
Short summary
Short summary
In this study we analyse the complex seasonal evolution of the East Asian summer monsoon. Using reanalysis data, we show the importance of the interaction between tropical and extratropical air masses converging at the monsoon front, particularly during its northward progression. The upper-level flow pattern (e.g. the westerly jet) controls the balance between the airstreams and thus the associated rainfall. This framework provides a basis for studies of extreme events and climate variability.
Peter Pfleiderer, Shruti Nath, and Carl-Friedrich Schleussner
Weather Clim. Dynam., 3, 471–482, https://doi.org/10.5194/wcd-3-471-2022, https://doi.org/10.5194/wcd-3-471-2022, 2022
Short summary
Short summary
Tropical cyclones are amongst the most dangerous weather events. Here we develop an empirical model that allows us to estimate the number and strengths of tropical cyclones for given atmospheric conditions and sea surface temperatures. An application of the model shows that atmospheric circulation is the dominant factor for seasonal tropical cyclone activity. However, warming sea surface temperatures have doubled the likelihood of extremely active hurricane seasons in the past decades.
Jean-Philippe Baudouin, Michael Herzog, and Cameron A. Petrie
Weather Clim. Dynam., 2, 1187–1207, https://doi.org/10.5194/wcd-2-1187-2021, https://doi.org/10.5194/wcd-2-1187-2021, 2021
Short summary
Short summary
Western disturbances are mid-latitude, high-altitude, low-pressure areas that bring orographic precipitation into the Upper Indus Basin. Using statistical tools, we show that the interaction between western disturbances and relief explains the near-surface, cross-barrier wind activity. We also reveal the existence of a moisture pathway from the nearby seas. Overall, we offer a conceptual framework for western-disturbance activity, particularly in terms of precipitation.
Anantha Aiyyer and Terrell Wade
Weather Clim. Dynam., 2, 1051–1072, https://doi.org/10.5194/wcd-2-1051-2021, https://doi.org/10.5194/wcd-2-1051-2021, 2021
Short summary
Short summary
We diagnose the mean circulations in the extratropics that are associated with rapid changes in the tropical storm storm speeds in the Atlantic. We show that rapid acceleration and deceleration are associated with distinct phasing between the tropical cyclone and weather waves of the extratropics. Over the past 5 decades, rapid acceleration and deceleration of tropical cyclones have reduced in magnitude. This might be related to the poleward shift and weakening of these extratropical waves.
Julianna Carvalho-Oliveira, Leonard Friedrich Borchert, Aurélie Duchez, Mikhail Dobrynin, and Johanna Baehr
Weather Clim. Dynam., 2, 739–757, https://doi.org/10.5194/wcd-2-739-2021, https://doi.org/10.5194/wcd-2-739-2021, 2021
Short summary
Short summary
This work questions the influence of the Atlantic Meridional Overturning Circulation, an important component of the climate system, on the variability in North Atlantic sea surface temperature (SST) a season ahead, particularly how this influence affects SST prediction credibility 2–4 months into the future. While we find this relationship is relevant for assessing SST predictions, it strongly depends on the time period and season we analyse and is more subtle than what is found in observations.
Andrea M. Jenney, David A. Randall, and Elizabeth A. Barnes
Weather Clim. Dynam., 2, 653–673, https://doi.org/10.5194/wcd-2-653-2021, https://doi.org/10.5194/wcd-2-653-2021, 2021
Short summary
Short summary
Storm activity in the tropics is one of the key phenomena that provide weather predictability on an extended timescale of about 10–40 d. The influence of tropical storminess on places like North America is sensitive to the overall average state of the climate system. In this study, we try to unpack the reasons why climate models do not agree on how the influence of these storms on weather over the North Pacific and North America will change in the future.
Philip Rupp and Peter Haynes
Weather Clim. Dynam., 2, 413–431, https://doi.org/10.5194/wcd-2-413-2021, https://doi.org/10.5194/wcd-2-413-2021, 2021
Short summary
Short summary
We study a range of dynamical aspects of the Asian monsoon anticyclone as the response of a simple numerical model to a steady imposed heating distribution with different background flow configurations. Particular focus is given on interactions between the monsoon anticyclone and active mid-latitude dynamics, which we find to have a zonally localising effect on the time-mean circulation and to be able to qualitatively alter the temporal variability of the bulk anticyclone.
Joshua White and Anantha Aiyyer
Weather Clim. Dynam., 2, 311–329, https://doi.org/10.5194/wcd-2-311-2021, https://doi.org/10.5194/wcd-2-311-2021, 2021
Short summary
Short summary
Using a simple general circulation model, we examine the structure of waves in the mid-tropospheric jet over North Africa. We show that waves occur in near-stationary groups or wave packets. As they are not swept out of the jet, this may provide the opportunity for the packets to amplify via feedback from other energy sources like rain-producing cloud complexes and mineral dust that are known to operate here. Our results address the criticism that the easterly jet is too short to sustain waves.
Franziska Aemisegger, Raphaela Vogel, Pascal Graf, Fabienne Dahinden, Leonie Villiger, Friedhelm Jansen, Sandrine Bony, Bjorn Stevens, and Heini Wernli
Weather Clim. Dynam., 2, 281–309, https://doi.org/10.5194/wcd-2-281-2021, https://doi.org/10.5194/wcd-2-281-2021, 2021
Short summary
Short summary
The interaction of clouds in the trade wind region with the atmospheric flow is complex and at the heart of uncertainties associated with climate projections. In this study, a natural tracer of atmospheric circulation is used to establish a link between air originating from dry regions of the midlatitudes and the occurrence of specific cloud patterns. Two pathways involving transport within midlatitude weather systems are identified, by which air is brought into the trades within 5–10 d.
Jack Giddings, Adrian J. Matthews, Nicholas P. Klingaman, Karen J. Heywood, Manoj Joshi, and Benjamin G. M. Webber
Weather Clim. Dynam., 1, 635–655, https://doi.org/10.5194/wcd-1-635-2020, https://doi.org/10.5194/wcd-1-635-2020, 2020
Short summary
Short summary
The impact of chlorophyll on the southwest monsoon is unknown. Here, seasonally varying chlorophyll in the Bay of Bengal was imposed in a general circulation model coupled to an ocean mixed layer model. The SST increases by 0.5 °C in response to chlorophyll forcing and shallow mixed layer depths in coastal regions during the inter-monsoon. Precipitation increases significantly to 3 mm d-1 across Myanmar during June and over northeast India and Bangladesh during October, decreasing model bias.
Giorgia Di Capua, Jakob Runge, Reik V. Donner, Bart van den Hurk, Andrew G. Turner, Ramesh Vellore, Raghavan Krishnan, and Dim Coumou
Weather Clim. Dynam., 1, 519–539, https://doi.org/10.5194/wcd-1-519-2020, https://doi.org/10.5194/wcd-1-519-2020, 2020
Short summary
Short summary
We study the interactions between the tropical convective activity and the mid-latitude circulation in the Northern Hemisphere during boreal summer. We identify two circumglobal wave patterns with phase shifts corresponding to the South Asian and the western North Pacific monsoon systems at an intra-seasonal timescale. These patterns show two-way interactions in a causal framework at a weekly timescale and assess how El Niño affects these interactions.
Benjamin A. Stephens and Charles S. Jackson
Weather Clim. Dynam., 1, 389–404, https://doi.org/10.5194/wcd-1-389-2020, https://doi.org/10.5194/wcd-1-389-2020, 2020
Short summary
Short summary
We analyze abrupt transitions between tropical rainfall regimes in a single-column model (SCM) of the tropical atmosphere. Multiple equilibria have been observed before in SCMs, but here we analyze actual bifurcations. We attribute the transitions to a sudden loss of evaporative cooling in the lower column due to nonlinearities in microphysics. This study may have implications for atmospheric dynamics more broadly but also for understanding abrupt transitions in paleoclimate.
Jorge L. García-Franco, Lesley J. Gray, and Scott Osprey
Weather Clim. Dynam., 1, 349–371, https://doi.org/10.5194/wcd-1-349-2020, https://doi.org/10.5194/wcd-1-349-2020, 2020
Short summary
Short summary
The American monsoon system is the main source of rainfall for the subtropical Americas and an important element of Latin American agriculture. Here we use state-of-the-art climate models from the UK Met Office in different configurations to analyse the performance of these models in the American monsoon. Resolution is found to be a key factor to improve monsoon representation, whereas integrated chemistry does not improve the simulated monsoon rainfall.
Cited articles
Alberti, T., Donner, R. V., and Vannitsem, S.: Multiscale fractal dimension analysis of a reduced order model of coupled ocean–atmosphere dynamics, Earth Syst. Dynam., 12, 837–855, https://doi.org/10.5194/esd-12-837-2021, 2021. a, b
Allan, R. J.: ENSO and Climatic Variability in the Past 150 Years, 3–56, Cambridge University Press, https://doi.org/10.1017/CBO9780511573125.002, 2000. a, b
An, S.-I., Tziperman, E., Okumura, Y. M., and Li, T.: ENSO Irregularity and Asymmetry, Chap. 7, American Geophysical Union (AGU), 153–172, https://doi.org/10.1002/9781119548164.ch7, 2020. a
Ashok, K., Behera, S. K., Rao, S. A., Weng, H., and Yamagata, T.: El Niño Modoki and its possible teleconnection, J. Geophys. Res.-Oceans, 112, C11007, https://doi.org/10.1029/2006JC003798, 2007. a
Baede, A., Ahlonsou, E., Ding, Y., and Schimel, D.: The Climate System: an Overview, Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 1–881, https://www.ipcc.ch/report/ar3/wg1/chapter-1-the-climate-system-an-overview/ (last access: 4 December 2023), 2001. a
Battisti, D. S. and Hirst, A. C.: Interannual Variability in a Tropical Atmosphere–Ocean Model: Influence of the Basic State, Ocean Geometry and Nonlinearity, J. Atmos. Sci., 46, 1687–1712, https://doi.org/10.1175/1520-0469(1989)046<1687:IVIATA>2.0.CO;2, 1989. a
Bejarano, L. and Jin, F.-F.: Coexistence of Equatorial Coupled Modes of ENSO, J. Climate, 21, 3051–3067, https://doi.org/10.1175/2007JCLI1679.1, 2008. a
Bjerknes, J.: ATMOSPHERIC TELECONNECTIONS FROM THE EQUATORIAL PACIFIC, Mon. Weather Rev., 97, 163–172, https://doi.org/10.1175/1520-0493(1969)097<0163:ATFTEP>2.3.CO;2, 1969. a
Boljka, L., Thompson, D. W. J., and Li, Y.: Downstream Suppression of Baroclinic Waves, J. Climate, 34, 919–930, https://doi.org/10.1175/JCLI-D-20-0483.1, 2021. a
Broomhead, D. S., Jones, R., and King, G. P.: Topological dimension and local coordinates from time series data, J. Phys. A-Math. Gen., 20, L563–L569, https://doi.org/10.1088/0305-4470/20/9/003, 1987. a
Brönnimann, S.: Impact of El Niño–Southern Oscillation on European climate, Rev. Geophys., 45, RG3003, https://doi.org/10.1029/2006RG000199, 2007. a
Capotondi, A., Sardeshmukh, P. D., and Ricciardulli, L.: The Nature of the Stochastic Wind Forcing of ENSO, J. Climate, 31, 8081–8099, https://doi.org/10.1175/JCLI-D-17-0842.1, 2018. a
Carton, J. A. and Giese, B. S.: A Reanalysis of Ocean Climate Using Simple Ocean Data Assimilation (SODA), Mon. Weather Rev., 136, 2999–3017, https://doi.org/10.1175/2007MWR1978.1, 2008 (data available at: http://apdrc.soest.hawaii.edu/dods/public_data/SODA/soda_pop2.2.4). a
Chen, H.-C., Jin, F.-F., Zhao, S., Wittenberg, A. T., and Xie, S.: ENSO Dynamics in the E3SM-1-0, CESM2, and GFDL-CM4 Climate Models, J. Climate, 34, 9365–9384, https://doi.org/10.1175/JCLI-D-21-0355.1, 2021. a
Choi, K.-Y., Vecchi, G. A., and Wittenberg, A. T.: ENSO Transition, Duration, and Amplitude Asymmetries: Role of the Nonlinear Wind Stress Coupling in a Conceptual Model, J. Climate, 26, 9462–9476, https://doi.org/10.1175/JCLI-D-13-00045.1, 2013. a
Crespo, L. R., Rodríguez-Fonseca, M. B., Polo, I., Keenlyside, N., and Dommenget, D.: Multidecadal variability of ENSO in a recharge oscillator framework, Environ. Res. Lett., 17, 074008, https://doi.org/10.1088/1748-9326/ac72a3, 2022. a, b, c, d
de la Cámara, A., Birner, T., and Albers, J. R.: Are Sudden Stratospheric Warmings Preceded by Anomalous Tropospheric Wave Activity?, J. Climate, 32, 7173–7189, https://doi.org/10.1175/JCLI-D-19-0269.1, 2019. a, b
Dommenget, D., Bayr, T., and Frauen, C.: Analysis of the non-linearity in the pattern and time evolution of El Niño southern oscillation, Clim. Dynam., 40, 2825–2847, https://doi.org/10.1007/s00382-012-1475-0, 2013. a, b
Duffy, D. G.: The Application of Hilbert–Huang Transforms to Meteorological Datasets, J. Atmos. Ocean. Tech., 21, 599–611, https://doi.org/10.1175/1520-0426(2004)021<0599:TAOHTT>2.0.CO;2, 2004. a
Ezer, T. and Corlett, W. B.: Is sea level rise accelerating in the Chesapeake Bay? A demonstration of a novel new approach for analyzing sea level data, Geophys. Res. Lett., 39, L19605, https://doi.org/10.1029/2012GL053435, 2012. a
Ezer, T., Atkinson, L. P., Corlett, W. B., and Blanco, J. L.: Gulf Stream's induced sea level rise and variability along the U.S. mid-Atlantic coast, J. Geophys. Res.-Oceans, 118, 685–697, https://doi.org/10.1002/jgrc.20091, 2013. a
Fedorov, A. V. and Philander, S. G.: Is El Niño Changing?, Science, 288, 1997–2002, https://doi.org/10.1126/science.288.5473.1997, 2000. a, b
Fedorov, A. V. and Philander, S. G.: A Stability Analysis of Tropical Ocean–Atmosphere Interactions: Bridging Measurements and Theory for El Niño, J. Climate, 14, 3086–3101, https://doi.org/10.1175/1520-0442(2001)014<3086:ASAOTO>2.0.CO;2, 2001. a
Fereday, D. R., Knight, J. R., Scaife, A. A., Folland, C. K., and Philipp, A.: Cluster Analysis of North Atlantic–European Circulation Types and Links with Tropical Pacific Sea Surface Temperatures, J. Climate, 21, 3687–3703, https://doi.org/10.1175/2007JCLI1875.1, 2008. a
Flandrin, P., Rilling, G., and Goncalves, P.: Empirical mode decomposition as a filter bank, IEEE Signal Proc. Let., 11, 112–114, https://doi.org/10.1109/LSP.2003.821662, 2004. a
Frankignoul, C. and Hasselmann, K.: Stochastic climate models, Part II Application to sea-surface temperature anomalies and thermocline variability, Tellus, 29, 289–305, https://doi.org/10.3402/tellusa.v29i4.11362, 1977. a, b
Franzke, C.: Multi-scale analysis of teleconnection indices: climate noise and nonlinear trend analysis, Nonlinear Proc. Geoph., 16, 65–76, https://doi.org/10.5194/npg-16-65-2009, 2009. a, b, c
Franzke, C.: Nonlinear Trends, Long-Range Dependence, and Climate Noise Properties of Surface Temperature, J. Climate, 25, 4172–4183, https://doi.org/10.1175/JCLI-D-11-00293.1, 2012. a
Franzke, C. and Woollings, T.: On the Persistence and Predictability Properties of North Atlantic Climate Variability, J. Climate, 24, 466–472, https://doi.org/10.1175/2010JCLI3739.1, 2011. a
Froyland, G., Giannakis, D., Lintner, B., Pike, M., and Slawinska, J.: Spectral analysis of climate dynamics with operator-theoretic approaches, Nat. Commun., 12, 6570, https://doi.org/10.1038/s41467-021-26357-x, 2021. a, b, c, d
Ghil, M., Allen, M. R., Dettinger, M. D., Ide, K., Kondrashov, D., Mann, M. E., Robertson, A. W., Saunders, A., Tian, Y., Varadi, F., and Yiou, P.: Advanced spectral methods for climatic time series, Rev. Geophys., 40, 3–1–3–41, https://doi.org/10.1029/2000RG000092, 2002. a
Guilyardi, E., Capotondi, A., Lengaigne, M., Thual, S., and Wittenberg, A. T.: ENSO Modeling, Chap. 9, American Geophysical Union (AGU), 199–226, https://doi.org/10.1002/9781119548164.ch9, 2020. a
Hardiman, S. C., Dunstone, N. J., Scaife, A. A., Smith, D. M., Ineson, S., Lim, J., and Fereday, D.: The Impact of Strong El Niño and La Niña Events on the North Atlantic, Geophys. Res. Lett., 46, 2874–2883, https://doi.org/10.1029/2018GL081776, 2019. a
Hasselmann, K.: Stochastic climate models Part I. Theory, Tellus, 28, 473–485, https://doi.org/10.1111/j.2153-3490.1976.tb00696.x, 1976. a, b
Hasselmann, K.: PIPs and POPs: The reduction of complex dynamical systems using principal interaction and oscillation patterns, J. Geophys. Res.-Atmos., 93, 11015–11021, https://doi.org/10.1029/JD093iD09p11015, 1988. a
Hu, Z.-Z., Kumar, A., Zhu, J., Huang, B., Tseng, Y.-h., and Wang, X.: On the Shortening of the Lead Time of Ocean Warm Water Volume to ENSO SST Since 2000, Sci. Rep., 7, 4294, https://doi.org/10.1038/s41598-017-04566-z, 2017. a
Hu, Z.-Z., Kumar, A., Huang, B., Zhu, J., L’Heureux, M., McPhaden, M. J., and Yu, J.-Y.: The Interdecadal Shift of ENSO Properties in 1999/2000: A Review, J. Climate, 33, 4441–4462, https://doi.org/10.1175/JCLI-D-19-0316.1, 2020. a
Huang, N. E., Shen, Z., Long, S. R., Wu, M. C., Shih, H. H., Zheng, Q., Yen, N.-C., Tung, C. C., and Liu, H. H.: The empirical mode decomposition and the Hilbert spectrum for nonlinear and non-stationary time series analysis, P. Roy. Soc. Lond. A Mat., 454, 903–995, https://doi.org/10.1098/rspa.1998.0193, 1998. a, b, c, d, e
Huang, N. E., Shen, Z., and Long, S. R.: A new view of nonlinear water waves: The Hilbert Spectrum, Annu. Rev. Fluid Mech., 31, 417–457, https://doi.org/10.1146/annurev.fluid.31.1.417, 1999. a
Huang, N. E., Wu, M.-L. C., Long, S. R., Shen, S. S., Qu, W., Gloersen, P., and Fan, K. L.: A confidence limit for the empirical mode decomposition and Hilbert spectral analysis, P. Roy. Soc. Lond. A Mat., 459, 2317–2345, https://doi.org/10.1098/rspa.2003.1123, 2003. a, b, c
Jajcay, N., Kravtsov, S., Sugihara, G., Tsonis, A. A., and Paluš, M.: Synchronization and causality across time scales in El Nño Southern Oscillation, NPJ Clim. Atmos. Sci., 1, 33, https://doi.org/10.1038/s41612-018-0043-7, 2018. a, b, c, d
Jenney, A. M., Randall, D. A., and Barnes, E. A.: Quantifying Regional Sensitivities to Periodic Events: Application to the MJO, J. Geophys. Res.-Atmos., 124, 3671–3683, https://doi.org/10.1029/2018JD029457, 2019. a
Jiang, N., Neelin, J. D., and Ghil, M.: Quasi-quadrennial and quasi-biennial variability in the equatorial Pacific, Clim. Dynam., 12, 101–112, https://doi.org/10.1007/BF00223723, 1995. a, b
Jiménez-Esteve, B. and Domeisen, D. I. V.: Nonlinearity in the tropospheric pathway of ENSO to the North Atlantic, Weather Clim. Dynam., 1, 225–245, https://doi.org/10.5194/wcd-1-225-2020, 2020. a
Jiménez-Esteve, B. and Domeisen, D. I. V.: The Tropospheric Pathway of the ENSO–North Atlantic Teleconnection, J. Climate, 31, 4563–4584, https://doi.org/10.1175/JCLI-D-17-0716.1, 2018. a
Jin, F.-F.: An Equatorial Ocean Recharge Paradigm for ENSO. Part II: A Stripped-Down Coupled Model, J. Atmos. Sci., 54, 830–847, https://doi.org/10.1175/1520-0469(1997)054<0830:AEORPF>2.0.CO;2, 1997b. a, b, c
Kao, H.-Y. and Yu, J.-Y.: Contrasting Eastern-Pacific and Central-Pacific Types of ENSO, J. Climate, 22, 615–632, https://doi.org/10.1175/2008JCLI2309.1, 2009. a
Keenlyside, N. S., Latif, M., and Dürkop, A.: On Sub-ENSO Variability, J. Climate, 20, 3452–3469, https://doi.org/10.1175/JCLI4199.1, 2007. a, b
Kim, K.-Y., O'Brien, J. J., and Barcilon, A. I.: The Principal Physical Modes of Variability over the Tropical Pacific, Earth Interact., 7, 1–32, https://doi.org/10.1175/1087-3562(2003)007<0001:TPPMOV>2.0.CO;2, 2003. a
Kretschmer, M., Adams, S. V., Arribas, A., Prudden, R., Robinson, N., Saggioro, E., and Shepherd, T. G.: Quantifying causal pathways of teleconnections, B. Am. Meteorol. Soc., 102, E2247–E2263, https://doi.org/10.1175/BAMS-D-20-0117.1, 2021. a
Laszuk, D.: Python implementation of Empirical Mode Decomposition algorithm, Zenodo [code], https://doi.org/10.5281/zenodo.5459184, 2017.
Lee, J., Planton, Y. Y., Gleckler, P. J., Sperber, K. R., Guilyardi, E., Wittenberg, A. T., McPhaden, M. J., and Pallotta, G.: Robust Evaluation of ENSO in Climate Models: How Many Ensemble Members Are Needed?, Geophys. Res. Lett., 48, e2021GL095041, https://doi.org/10.1029/2021GL095041, 2021. a
Lee, T. and Ouarda, T. B. M. J.: Prediction of climate nonstationary oscillation processes with empirical mode decomposition, J. Geophys. Res.-Atmos., 116, D06107, https://doi.org/10.1029/2010JD015142, 2011. a
L'Heureux, M. L., Levine, A. F. Z., Newman, M., Ganter, C., Luo, J.-J., Tippett, M. K., and Stockdale, T. N.: ENSO Prediction, Chap. 10, American Geophysical Union (AGU), 227–246, https://doi.org/10.1002/9781119548164.ch10, 2020. a
Lopez, H. and Kirtman, B. P.: WWBs, ENSO predictability, the spring barrier and extreme events, J. Geophys. Res.-Atmos., 119, 10114–10138, https://doi.org/10.1002/2014JD021908, 2014. a
Lopez, H., Kirtman, B. P., Tziperman, E., and Gebbie, G.: Impact of interactive westerly wind bursts on CCSM3, Dynam. Atmos. Oceans, 59, 24–51, https://doi.org/10.1016/j.dynatmoce.2012.11.001, 2013. a
Madden, R. A. and Julian, P. R.: Detection of a 40–50 Day Oscillation in the Zonal Wind in the Tropical Pacific, J. Atmos. Sci., 28, 702–708, https://doi.org/10.1175/1520-0469(1971)028<0702:DOADOI>2.0.CO;2, 1971. a, b, c, d
Mariotti, A., Ruti, P. M., and Rixen, M.: Progress in subseasonal to seasonal prediction through a joint weather and climate community effort, NPJ Clim. Atmos. Sci., 1, 4, https://doi.org/10.1038/s41612-018-0014-z, 2018. a
Mariotti, A., Baggett, C., Barnes, E. A., Becker, E., Butler, A., Collins, D. C., Dirmeyer, P. A., Ferranti, L., Johnson, N. C., Jones, J., Kirtman, B. P., Lang, A. L., Molod, A., Newman, M., Robertson, A. W., Schubert, S., Waliser, D. E., and Albers, J.: Windows of Opportunity for Skillful Forecasts Subseasonal to Seasonal and Beyond, B. Am. Meteorol. Soc., 101, E608–E625, https://doi.org/10.1175/BAMS-D-18-0326.1, 2020. a
Penland, C. and Sardeshmukh, P. D.: The Optimal Growth of Tropical Sea Surface Temperature Anomalies, J. Climate, 8, 1999–2024, https://doi.org/10.1175/1520-0442(1995)008<1999:TOGOTS>2.0.CO;2, 1995. a
Philander, S. G. H.: El Niño, La Niña, and the southern oscillation, Academic Press, Inc., San Diego, California, ISBN 9780125532358, 1989. a
Picaut, J., Masia, F., and du Penhoat, Y.: An Advective-Reflective Conceptual Model for the Oscillatory Nature of the ENSO, Science, 277, 663–666, https://doi.org/10.1126/science.277.5326.663, 1997. a
Planton, Y. Y., Guilyardi, E., Wittenberg, A. T., Lee, J., Gleckler, P. J., Bayr, T., McGregor, S., McPhaden, M. J., Power, S., Roehrig, R., Vialard, J., and Voldoire, A.: Evaluating Climate Models with the CLIVAR 2020 ENSO Metrics Package, B. Am. Meteorol. Soc., 102, E193–E217, https://doi.org/10.1175/BAMS-D-19-0337.1, 2021. a
Qian, C., Wu, Z., Fu, C., and Wang, D.: On Changing El Niño: A View from Time-Varying Annual Cycle, Interannual Variability, and Mean State, J. Climate, 24, 6486–6500, https://doi.org/10.1175/JCLI-D-10-05012.1, 2011. a
Rayner, N. A., Parker, D. E., Horton, E. B., Folland, C. K., Alexander, L. V., Rowell, D. P., Kent, E. C., and Kaplan, A.: Global analyses of sea surface temperature, sea ice, and night marine air temperature since the late nineteenth century, J. Geophys. Res., 108, 4407, https://doi.org/10.1029/2002JD002670, 2003 (data available at: https://www.metoffice.gov.uk/hadobs/hadisst). a
Rehman, N. and Mandic, D. P.: Filter Bank Property of Multivariate Empirical Mode Decomposition, IEEE T. Signal Proces. 59, 2421–2426, https://doi.org/10.1109/TSP.2011.2106779, 2011. a
Rilling, G., Flandrin, P., and Gonçalves, P.: On empirical mode decomposition and its algorithms, in: Proceedings of IEEE-EURASIP Workshop on Nonlinear Signal and Image Processing NSIP-03, Grado, Italy, https://hal.inria.fr/inria-00570628 (last access: 4 December 2023), 2003. a
Rilling, G., Flandrin, P., Goncalves, P., and Lilly, J. M.: Bivariate Empirical Mode Decomposition, IEEE T. Signal Proces., 14, 936–939, https://doi.org/10.1109/LSP.2007.904710, 2007. a
Roulston, M. S. and Neelin, J. D.: The response of an ENSO Model to climate noise, weather noise and intraseasonal forcing, Geophys. Res. Lett., 27, 3723–3726, https://doi.org/10.1029/2000GL011941, 2000. a
Runge, J., Petoukhov, V., Donges, J. F., Hlinka, J., Jajcay, N., Vejmelka, M., Hartman, D., Marwan, N., Paluš, M., and Kurths, J.: Identifying causal gateways and mediators in complex spatio-temporal systems, Nat. Commun., 6, 8502, https://doi.org/10.1038/ncomms9502, 2015. a
Singh, A. and Delcroix, T.: Eastern and Central Pacific ENSO and their relationships to the recharge/discharge oscillator paradigm, Deep-Sea Res. Pt. I, 82, 32–43, https://doi.org/10.1016/j.dsr.2013.08.002, 2013. a
Slawinska, J. and Giannakis, D.: Indo-Pacific Variability on Seasonal to Multidecadal Time Scales. Part I: Intrinsic SST Modes in Models and Observations, J. Climate, 30, 5265–5294, https://doi.org/10.1175/JCLI-D-16-0176.1, 2017. a
Stallone, A., Cicone, A., and Materassi, M.: New insights and best practices for the successful use of Empirical Mode Decomposition, Iterative Filtering and derived algorithms, Sci. Rep., 10, 15161, https://doi.org/10.1038/s41598-020-72193-2, 2020. a, b, c
Stein, K., Schneider, N., Timmermann, A., and Jin, F.-F.: Seasonal Synchronization of ENSO Events in a Linear Stochastic Model, J. Climate, 23, 5629–5643, https://doi.org/10.1175/2010JCLI3292.1, 2010. a, b
Suarez, M. J. and Schopf, P. S.: A Delayed Action Oscillator for ENSO, J. Atmos. Sci., 45, 3283–3287, https://doi.org/10.1175/1520-0469(1988)045<3283:ADAOFE>2.0.CO;2, 1988. a
Timmermann, A., An, S. I., Kug, J. S., Jin, F. F., Cai, W., Capotondi, A., Cobb, K. M., Lengaigne, M., McPhaden, M. J., Stuecker, M. F., Stein, K., Wittenberg, A. T., Yun, K. S., Bayr, T., Chen, H. C., Chikamoto, Y., Dewitte, B., Dommenget, D., Grothe, P., Guilyardi, E., Ham, Y. G., Hayashi, M., Ineson, S., Kang, D., Kim, S., Kim, W., Lee, J. Y., Li, T., Luo, J. J., McGregor, S., Planton, Y., Power, S., Rashid, H., Ren, H. L., Santoso, A., Takahashi, K., Todd, A., Wang, G., Wang, G., Xie, R., Yang, W. H., Yeh, S. W., Yoon, J., Zeller, E., and Zhang, X.: El Nino-Southern Oscillation complexity, Nature, 559, 535–545, https://doi.org/10.1038/s41586-018-0252-6, 2018. a, b
Wang, B. and An, S.-I.: Why the properties of El Niño changed during the late 1970s, Geophys. Res. Lett., 28, 3709–3712, https://doi.org/10.1029/2001GL012862, 2001. a
Wang, C.: A Unified Oscillator Model for the El Niño-Southern Oscillation, J. Climate, 14, 98–115, https://doi.org/10.1175/1520-0442(2001)014<0098:AUOMFT>2.0.CO;2, 2001. a, b, c
Wang, C. and Fiedler, P. C.: ENSO variability and the eastern tropical Pacific: A review, Prog. Oceanogr., 69, 239–266, https://doi.org/10.1016/j.pocean.2006.03.004, 2006. a
Wang, C., Weisberg, R. H., and Virmani, J. I.: Western Pacific interannual variability associated with the El Niño-Southern Oscillation, J. Geophys. Res.-Oceans, 104, 5131–5149, https://doi.org/10.1029/1998JC900090, 1999. a, b
Wang, R. and Ren, H.-L.: Understanding Key Roles of Two ENSO Modes in Spatiotemporal Diversity of ENSO, J. Climate, 33, 6453–6469, https://doi.org/10.1175/JCLI-D-19-0770.1, 2020. a, b, c
Weisberg, R. H. and Wang, C.: A Western Pacific Oscillator Paradigm for the El Niño-Southern Oscillation, Geophys. Res. Lett., 24, 779–782, https://doi.org/10.1029/97GL00689, 1997. a
Wengel, C., Latif, M., Park, W., Harlaß, J., and Bayr, T.: Seasonal ENSO phase locking in the Kiel Climate Model: The importance of the equatorial cold sea surface temperature bias, Clim. Dynam., 50, 901–919, https://doi.org/10.1007/s00382-017-3648-3, 2018. a
Wittenberg, A. T.: Extended Wind Stress Analyses for ENSO, J. Climate, 17, 2526–2540, https://doi.org/10.1175/1520-0442(2004)017<2526:EWSAFE>2.0.CO;2, 2004. a
Wu, Z. and Huang, N. E.: Ensemble empirical mode decomposition: a noise-assisted data analysis method, Advances in Adaptive Data Analysis, 1, 1–41, https://doi.org/10.1142/S1793536909000047, 2009. a
Wu, Z., Huang, N. E., Long, S. R., and Peng, C.-K.: On the trend, detrending, and variability of nonlinear and nonstationary time series, P. Natl. Acad. Sci. USA, 104, 14889–14894, https://doi.org/10.1073/pnas.0701020104, 2007. a
Zhang, Z., Ren, B., and Zheng, J.: A unified complex index to characterize two types of ENSO simultaneously, Sci. Rep., 9, 8373, https://doi.org/10.1038/s41598-019-44617-1, 2019. a
Short summary
This study examines quasi-periodic variability in the tropical Pacific on interannual timescales and related physics using a recently developed time series analysis tool. We find that wind stress in the west Pacific and recharge–discharge of ocean heat content are likely related to each other on ~1.5–4.5-year timescales (but not on others) and dominate variability in sea surface temperatures on those timescales. This may have further implications for climate models and long-term prediction.
This study examines quasi-periodic variability in the tropical Pacific on interannual timescales...
