Article
Meteorology & Atmospheric Sciences
Jiye Wu, Yue Li, Jing-Jia Luo, Xianan Jiang
Summary: This study compares MJO predictions based on an atmosphere-ocean coupled model and atmosphere models, finding that the CGCM model shows better performance, particularly in predicting moistening processes and boundary layer moisture preconditioning. Improved prediction of MJO moisture processes in CGCM is associated with better representation of MJO circulation and stronger Kelvin waves, which contribute to MJO eastward propagation. The study confirms the critical role of atmosphere-ocean coupling in improving MJO prediction.
JOURNAL OF CLIMATE
(2021)
Article
Meteorology & Atmospheric Sciences
Kai Huang, Kathleen Pegion
Summary: This study focuses on the stand and jump types of the Madden-Julian oscillation (MJO). It reveals the influence of the westward-propagating wave (WPW), QBO, and ENSO on MJO propagation. The jump MJO is influenced by the QBO and ENSO, leading to independent convection over the Pacific, while the stand MJO is constrained by La Nina-like cool SST anomalies, preventing independent convection over the central Pacific.
JOURNAL OF CLIMATE
(2022)
Article
Meteorology & Atmospheric Sciences
Hai Lin, Zhiyong Huang, Harry Hendon, Gilbert Brunet
Summary: The study reveals that the NAO has a significant influence on the MJO and its forecast skill, with most models able to capture this influence. The amplitude and phase of the NAO affect the MJO prediction skill, with a strong NAO leading to better forecasting. Additionally, forecasts starting from a negative NAO tend to have higher MJO skill compared to those starting from a positive NAO.
JOURNAL OF CLIMATE
(2021)
Article
Meteorology & Atmospheric Sciences
Xiaojing Li, Youmin Tang
Summary: This study uses a 19-year ensemble hindcast from ECMWF and the APT method to identify the most predictable tropical intraseasonal variability mode. The APT1 mode is characterized by a tripole pattern with longer skillful prediction period, potentially originating from oceanic influences. Tropical ocean-atmosphere interaction and internal atmospheric processes play crucial roles in the formation and maintenance of the APT1 mode.
JOURNAL OF CLIMATE
(2021)
Article
Meteorology & Atmospheric Sciences
Tianyi Wang, Tim Li
Summary: This study examined the diversity of the Madden-Julian oscillation (MJO) in terms of its maximum intensity, zonal extent, and phase speed using a cluster analysis method. The results showed significant correlations between zonal extent and phase speed, as well as connections between these diversities and interannual sea surface temperature anomalies and associated moisture and circulation patterns over the equatorial Pacific. An El Nino-like background SSTA was found to be a key factor influencing the behavior of MJO in terms of zonal extent, phase speed, and intensity.
JOURNAL OF CLIMATE
(2021)
Article
Meteorology & Atmospheric Sciences
Stephanie S. Rushley, Daehyun Kang, Daehyun Kim, Soon-il An, Teng Wang
Summary: This study explores the factors that control the maximum in MJO precipitation variance in the Southern Hemisphere during boreal winter. By altering the eccentricity and precession of Earth's orbit, the researchers find that changes in sea surface temperature and Hadley circulation strengthen the MJO's amplitude. The mean-state precipitation is identified as a critical factor in the maintenance mechanism of the MJO.
JOURNAL OF CLIMATE
(2023)
Article
Meteorology & Atmospheric Sciences
Chuan-chieh Chang, Sandro w. Lubis, Karthik Balaguru, L. ruby Leung, Samson m. Hagos, Philip j. Klotzbach
Summary: This study investigates the combined impacts of the Madden-Julian oscillation (MJO) and extratropical an-ticyclonic Rossby wave breaking (AWB) on subseasonal Atlantic tropical cyclone (TC) activity and their physical connections. The results show that both the MJO and AWB play a role in suppressing TC activity during certain phases, with AWB events in phases 6-7 having a greater impact on TC development than their phases 2-3 counterparts. The study also finds that the influence of the MJO on AWB in the western subtropical Atlantic can be attributed to the modulation of the convectively forced Rossby wave source over the tropical eastern Pacific.
JOURNAL OF CLIMATE
(2023)
Article
Meteorology & Atmospheric Sciences
Bruno dos Santos Guimaraes, Caio Augusto dos Santos Coelho, Steven James Woolnough, Paulo Yoshio Kubota, Carlos Frederico Bastarz, Silvio Nilo Figueroa, Jose Paulo Bonatti, Dayana Castilho de Souza
Summary: This study conducted an inter-comparison performance evaluation of the newly developed Brazilian Atmospheric Model against four S2S prediction project models, with ECMWF performing the best in precipitation anomaly prediction. CPTEC showed competitive performance in MJO predictions compared to the other models.
Article
Meteorology & Atmospheric Sciences
Hong-Li Ren, Yuntao Wei, Shuo Zhao
Summary: The real-time multivariate Madden-Julian oscillation (MJO) (RMM) index has been widely used in operational subseasonal prediction and monitoring. However, this study reveals that the real-time strategy used to calculate this index artificially introduces unwanted low-frequency variability (LFVartificial), which can have significant impacts on the amplitude and phase of the MJO. These interference effects are particularly strong when the background state is changing rapidly with time or during the boreal summer.
JOURNAL OF CLIMATE
(2023)
Article
Geosciences, Multidisciplinary
Savini M. Samarasinghe, Charlotte Connolly, Elizabeth A. Barnes, Imme Ebert-Uphoff, Lantao Sun
Summary: This study investigates the changes in causal pathways between the Madden-Julian Oscillation (MJO) and the North Atlantic Oscillation (NAO) using historical and SSP585 simulations of the CESM2-WACCM coupled climate model. The results show that the influence of MJO on the North Atlantic strengthens in the future, primarily through teleconnections via the tropospheric pathway.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Meteorology & Atmospheric Sciences
David A. MacLeod, Rutger Dankers, Richard Graham, Kiswendsida Guigma, Luke Jenkins, Martin C. Todd, Augustine Kiptum, Mary Kilavi, Andrew Njogu, Emmah Mwangi
Summary: Equatorial East Africa faces significant flood risks, which can be mitigated with preemptive action. Subseasonal climate forecasts show skill in predicting extreme rainfall events in the region at lead times of 2 weeks and beyond. Weekly rainfall totals are found to be relevant for fluvial flood risk, with heavy rainfall and high antecedent rainfall conditions identified as key drivers. Promising skill in subseasonal forecasts suggests their potential use in enhancing preparedness activities in the region.
JOURNAL OF HYDROMETEOROLOGY
(2021)
Article
Meteorology & Atmospheric Sciences
Daehyun Kang, Daehyun Kim, Min-Seop Ahn, Soon-Il An
Summary: This study investigates the impact of the background meridional moisture gradient (MMG) on the propagation of the Madden-Julian oscillation (MJO) across the Maritime Continent (MC) region. The seasonal mean MMG variability over the southern MC area is associated with the expansion and contraction of the moist area, influencing the MJO propagation. Higher (lower) seasonal mean MMG years enhance (suppress) MJO propagation through the MC.
JOURNAL OF CLIMATE
(2021)
Article
Meteorology & Atmospheric Sciences
Stephanie S. Rushley, Matthew A. Janiga, James A. Ridout, Carolyn A. Reynolds
Summary: The Madden-Julian oscillation (MJO) is an important source of predictability in the subseasonal time scale, but there are still biases in MJO behavior and structure in climate and forecast models. The MJO in the Navy Earth System Prediction Capability (Navy ESPC) forecasts is too strong and the moisture advection and convective moisture adjustment time scale in the Navy ESPC are biased, leading to an overestimation of precipitation response. The MJO propagation in the Navy ESPC shows strong agreement with observations in the Indian Ocean, but too rapid propagation east of the Maritime Continent in both seasons due to biases in moisture tendency.
MONTHLY WEATHER REVIEW
(2022)
Article
Geosciences, Multidisciplinary
Shuguang Wang, Adam H. Sobel
Summary: The authors propose a new approximation method to understand the moisture modes in idealized models of tropical intraseasonal oscillations. This method provides physical insights and filters out disturbances, enhancing the understanding of these oscillation patterns.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Environmental Sciences
Wu Nan, Li Ying, Li Juan, Feng Li-Cheng, Liu Fei
Summary: The study found significant decadal changes in the properties of the Intraseasonal Oscillation (ISO) since 1998, mainly in its evolution rather than its intensity. The boreal summer ISO has shown northeastward propagation since 1998, enhancing intraseasonal variability over the western North Pacific. Meanwhile, the Madden-Julian Oscillation (MJO) in boreal winter has shown minor changes in its barrier effect in the Maritime Continent and continues to propagate eastward.
ADVANCES IN CLIMATE CHANGE RESEARCH
(2021)
Article
Meteorology & Atmospheric Sciences
Hai Lin, William J. Merryfield, Ryan Muncaster, Gregory C. Smith, Marko Markovic, Frederic Dupont, Francois Roy, Jean-Francois Lemieux, Arlan Dirkson, Viatcheslav V. Kharin, Woo-Sung Lee, Martin Charron, Amin Erfani
WEATHER AND FORECASTING
(2020)
Article
Meteorology & Atmospheric Sciences
Nicholas Soulard, Hai Lin, Jacques Derome, Bin Yu
Summary: Recent studies have shown that the South Asian jet can affect climatic conditions across the entire hemisphere. The study found that during the boreal winter in the Northern Hemisphere, imposing a diabatic heating anomaly in the tropics can force a CGT pattern.
Article
Meteorology & Atmospheric Sciences
Pei-Ning Feng, Hai Lin
Summary: The study evaluates the modulation of the MJO-related teleconnection by the QBO in operational models, showing that the S2S models capture the enhancement of the NAO under WQBO conditions to varying degrees but struggle to reproduce the effect under EQBO conditions.
Article
Meteorology & Atmospheric Sciences
Hai Lin, Zhiyong Huang, Harry Hendon, Gilbert Brunet
Summary: The study reveals that the NAO has a significant influence on the MJO and its forecast skill, with most models able to capture this influence. The amplitude and phase of the NAO affect the MJO prediction skill, with a strong NAO leading to better forecasting. Additionally, forecasts starting from a negative NAO tend to have higher MJO skill compared to those starting from a positive NAO.
JOURNAL OF CLIMATE
(2021)
Article
Meteorology & Atmospheric Sciences
Hal Ritchie, Stephane Belair, Natacha B. Bernier, Mark Buehner, Martin Charron, Vincent Fortin, Louis Garand, Pieter Houtekamer, Syed Husain, Stephane Laroche, Jean-Francois Lemieux, Hai Lin, Ron McTaggart-Cowan, Jason Milbrandt, Herschel Mitchell, Pierre Pellerin, Janusz Pudykiewicz, Leo Separovic, Gregory C. Smith, Monique Tanguay, Paul A. Vaillancourt
Summary: Contributions of Recherche en Prevision Numerique (RPN) to Numerical Weather Prediction (NWP): A review article invited by Atmosphere-Ocean
Article
Meteorology & Atmospheric Sciences
Cristiana Stan, Cheng Zheng, Edmund Kar-Man Chang, Daniela I. Domeisen, Chaim Garfinkel, Andrea M. Jenney, Hyemi Kim, Young-Kwon Lim, Hai Lin, Andrew Robertson, Chen Schwartz, Frederic Vitart, Jiabao Wang, Priyanka Yadav
Summary: This study evaluates the ability of state-of-the-art S2S forecasting systems to represent and predict the teleconnections of the Madden-Julian oscillation and their effects on weather, providing valuable insights for modeling community on further development focus.
BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY
(2022)
Article
Meteorology & Atmospheric Sciences
Jialin Lin, Taotao Qian, Howard B. Bluestein, Peter Ditlevsen, Hai Lin, Tatsuya Seiki, Eigo Tochimoto, Hannah Barnes, Peter Bechtold, Frederick H. Carr, Saulo R. Freitas, Steven J. Goodman, Georg Grell, Jongil Han, Philip Klotzbach, Woosub Roh, Masaki Satoh, Siegfried Schubert, Guang Zhang, Ping Zhu
Summary: This paper summarizes the current challenges in climate and weather research and provides suggestions for future research directions.
Article
Meteorology & Atmospheric Sciences
Hai Lin
Summary: This review article discusses the rich variabilities in the global atmosphere and climate system on the intraseasonal time scale, with a focus on the Madden-Julian Oscillation (MJO) as the dominant mode of tropical intraseasonal variability. The MJO has a significant global impact and is a major source of skill for subseasonal to seasonal predictions.
Article
Geosciences, Multidisciplinary
Hai Lin, Ruping Mo, Frederic Vitart
Summary: This study evaluates the ability of 10 Subseasonal-to-Seasonal prediction models to predict above-normal temperatures in western North America 2-3 weeks in advance. It is found that most models were able to predict the high temperatures in Western Canada during June 28-July 4 as early as June 10. However, for forecasts initialized earlier than June 17, none of the models could accurately capture the magnitude of the observed temperature anomaly. The study identifies the importance of two processes: an upper tropospheric wave train associated with the boreal summer intraseasonal oscillation in Southeast Asia, and an anomalous North Pacific atmospheric river leading to high moisture conditions. Most models were able to predict the wave train across the North Pacific, but a realistic representation of moisture transport and its pattern appears crucial for the extended-range forecast of this heatwave.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Editorial Material
Meteorology & Atmospheric Sciences
Jialin Lin, Hai Lin
Article
Meteorology & Atmospheric Sciences
K. Andrew Peterson, Gregory C. Smith, Jean-Francois Lemieux, Francois Roy, Mark Buehner, Alain Caya, Pieter L. Houtekamer, Hai Lin, Ryan Muncaster, Xingxiu Deng, Frederic Dupont, Normand Gagnon, Yukie Hata, Yosvany Martinez, Juan Sebastian Fontecilla, Dorina Surcel-Colan
Summary: The Global Ensemble Prediction System (GEPS) of Environment and Climate Change Canada has been upgraded to a coupled atmosphere, ocean, and sea-ice version, and shows improved sea-ice prediction compared to persistence and a deterministic Global Deterministic Prediction System (GDPS). The ensemble system offers enhanced benefits over a single deterministic forecast during the minimum and maximum extent periods and the early freeze-up period, although further improvement of the spread/error relationship is needed.
QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY
(2022)
Article
Meteorology & Atmospheric Sciences
Andrew G. Marshall, Guomin Wang, Harry H. Hendon, Hai Lin
Summary: The Madden-Julian Oscillation (MJO) has a significant impact on Australian springtime temperatures and extremes. It induces strong warming in southern Australia when its active convection propagates over the Indian Ocean and Maritime Continent. The heat signal is strongest in southeast Australia during specific MJO phases, in the vicinity of a deep anticyclonic anomaly. These temperature fluctuations are part of a Rossby wave train that originates from the Indian Ocean and disperses across the Southern Hemisphere towards South America.
Article
Environmental Sciences
Ruping Mo, Hai Lin, Frederic Vitart
Summary: Based on analyses of observation-based data and numerical weather prediction model output, this study reveals that a warm-season atmospheric river moved from Southeast Asia across the North Pacific in June 2021, contributing heat and moisture to a heatwave event in western North America. The movement of this system resulted in substantial spillover of moisture and sensible heat, forming a positive feedback mechanism that potentially led to the expansion of the heatwave event.
COMMUNICATIONS EARTH & ENVIRONMENT
(2022)
Article
Geosciences, Multidisciplinary
Yongkang Xue, Tandong Yao, Aaron A. Boone, Ismaila Diallo, Ye Liu, Xubin Zeng, William K. M. Lau, Shiori Sugimoto, Qi Tang, Xiaoduo Pan, Peter J. van Oevelen, Daniel Klocke, Myung-Seo Koo, Tomonori Sato, Zhaohui Lin, Yuhei Takaya, Constantin Ardilouze, Stefano Materia, Subodh K. Saha, Retish Senan, Tetsu Nakamura, Hailan Wang, Jing Yang, Hongliang Zhang, Mei Zhao, Xin-Zhong Liang, J. David Neelin, Frederic Vitart, Xin Li, Ping Zhao, Chunxiang Shi, Weidong Guo, Jianping Tang, Miao Yu, Yun Qian, Samuel S. P. Shen, Yang Zhang, Kun Yang, Ruby Leung, Yuan Qiu, Daniele Peano, Xin Qi, Yanling Zhan, Michael A. Brunke, Sin Chan Chou, Michael Ek, Tianyi Fan, Hong Guan, Hai Lin, Shunlin Liang, Helin Wei, Shaocheng Xie, Haoran Xu, Weiping Li, Xueli Shi, Paulo Nobre, Yan Pan, Yi Qin, Jeff Dozier, Craig R. Ferguson, Gianpaolo Balsamo, Qing Bao, Jinming Feng, Jinkyu Hong, Songyou Hong, Huilin Huang, Duoying Ji, Zhenming Ji, Shichang Kang, Yanluan Lin, Weiguang Liu, Ryan Muncaster, Patricia de Rosnay, Hiroshi G. Takahashi, Guiling Wang, Shuyu Wang, Weicai Wang, Xu Zhou, Yuejian Zhu
Summary: The LS4P project aims to improve S2S prediction by introducing spring land surface temperature and snowpack anomalies as crucial factors. Over 40 groups worldwide have participated in LS4P, with preliminary results showing significant hydroclimatic impacts of the Tibetan Plateau LST.
GEOSCIENTIFIC MODEL DEVELOPMENT
(2021)
Article
Meteorology & Atmospheric Sciences
Bin Yu, Guilong Li, Hai Lin, Shangfeng Chen
Summary: The climate simulations conducted with two generations of Canadian Earth System Models reveal a poleward intensified warming trend and high risk of severe warm days over the west coast of North America and northern Canada, while the belt of extreme cold days extending from Alaska to the northeastern United States weakens. The warming trend is stronger in CanESM5 than in CanESM2, and there are large ensemble spreads in the SAT trend and extreme temperature projections.