Article
Meteorology & Atmospheric Sciences
Chengyang Zhang, Wenshou Tian, Jiankai Zhang, Tuantuan Zhang, Wei Yu, Song Yang, Tao Wang
Summary: The premonsoon circulation over South Asia in May shows interannual variations and can be influenced by the stratosphere-troposphere modes over the North Atlantic in April. These modes exhibit NAO-like circulation patterns, but have different circulation patterns and planetary wave activity. The first mode is a stratosphere-troposphere-coupled mode, which leads to a reduction in sea ice over the northern Barents Sea, generating anomalous circulation and strengthening the premonsoon circulation. The second mode, influenced by ENSO, also has a significant effect on the South Asian premonsoon circulations in May and is related to the NAO-like circulation.
JOURNAL OF CLIMATE
(2023)
Article
Geosciences, Multidisciplinary
Amy H. Butler, Alexey Yu. Karpechko, Chaim I. Garfinkel
Summary: The dominant pattern of Northern Hemisphere extratropical climate variability is the Northern Annular Mode (NAM), which represents the coupling of the stratospheric and tropospheric circulations in wintertime. The NAM has been shown to contribute to uncertainty in climate projections of regional surface air temperatures (SATs), but it is unclear how much of this variability comes from stratosphere-troposphere coupling processes. This study uses three large-ensemble coupled climate model simulations to demonstrate that regional SAT variability is amplified when the tropospheric NAM is coupled to the stratospheric NAM, and models that do not accurately simulate this coupling process may underestimate the uncertainty in near-term SAT projections.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Geosciences, Multidisciplinary
Amy H. Butler, Alexey Yu. Karpechko, Chaim I. Garfinkel
Summary: The Northern Annular Mode (NAM) is the dominant pattern of climate variability in the Northern Hemisphere, representing the coupling of stratospheric and tropospheric circulations. Internal variability associated with the NAM has been shown to contribute to uncertainty in regional surface air temperature projections. It is uncertain how much of this variability is due to stratosphere-troposphere coupling processes.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Meteorology & Atmospheric Sciences
Kane A. Stone, Susan Solomon, David W. J. Thompson, Douglas E. Kinnison, John C. Fyfe
Summary: This study investigates the relationship between ENSO events and the southern hemisphere (SH) stratospheric pathway. The research finds that ENSO is associated with stratospheric anomalies in the SH, with the warm phase of the ENSO cycle generally leading to a colder spring Antarctic stratosphere. This relationship is robust and consistent across multiple models. Additionally, the study reveals that the magnitude of the stratospheric pathway is weaker compared to the tropospheric pathway, playing a secondary role.
JOURNAL OF CLIMATE
(2022)
Article
Environmental Sciences
David D. Parrish, Richard G. Derwent, Ian C. Faloona, Charles A. Mims
Summary: A nonlinear change in baseline ozone concentrations has been observed at northern midlatitudes over the past few decades. Recent studies using linear trend analyses have reported relatively small trends, which are inconsistent with earlier findings. The COVID-19-related ozone changes based on linear analysis are shown to be significantly larger than recent long-term decreases in baseline ozone. The loss of lower stratospheric ozone in the 2020 springtime Arctic stratospheric ozone depletion event also contributed to anomalously low background ozone levels. Taken together, these factors suggest that the impact of COVID-19 restrictions on background tropospheric ozone in 2020 was smaller than previously reported. A consensus understanding of baseline ozone changes and their causes is crucial for developing effective policies to improve ozone air quality.
ATMOSPHERIC CHEMISTRY AND PHYSICS
(2022)
Article
Meteorology & Atmospheric Sciences
Ruhua Zhang, Wen Zhou, Wenshou Tian, Yue Zhang, Zhenchen Liu, Paxson K. Y. Cheung
Summary: This study re-examines the impact of El Nino-Southern Oscillation (ENSO) on the winter stratospheric polar vortex intensity (PVI) and finds that the negative correlation between ENSO and PVI has weakened in recent decades and is no longer statistically significant. This weakening is associated with changes in wave-1 fluxes entering the stratosphere.
JOURNAL OF CLIMATE
(2022)
Article
Meteorology & Atmospheric Sciences
Martin Jucker, Thomas Reichler
Summary: Based on a multimillennial climate model simulation, it is found that sudden stratospheric warmings (SSWs) in the Southern Hemisphere (SH) are mainly displacement events forced by wave-1 planetary waves. A surface signature similar to the negative phase of the Southern Annular Mode (SAM) can be detected up to two months before the onset date, but there is a tendency for a transition from wave 1 before to zonally symmetric anomalies after onset. The weakening of the Amundsen Sea low is identified as a prominent precursor for SH SSWs, and the Indian Ocean dipole is more important than El Nino-Southern Oscillation.
JOURNAL OF CLIMATE
(2023)
Article
Meteorology & Atmospheric Sciences
Xiaocen Shen, Lin Wang, Adam A. Scaife, Steven C. Hardiman, Peiqiang Xu
Summary: This study finds that the location shift dominates the intra-seasonal variability of the stratospheric polar vortex (SPV), forming an intra-seasonal stratosphere-troposphere oscillation (STO) that reflects the movement of the SPV across different regions. The mechanism of the STO involves Rossby wave propagation and cross-scale interactions. The STO unifies the SPV shifts, tropospheric disturbances, and wave coupling processes, providing a holistic view of the intraseasonal stratosphere-troposphere coupling. The STO may serve as a potential source of predictability for subseasonal-to-seasonal climate prediction.
JOURNAL OF CLIMATE
(2023)
Article
Environmental Sciences
Jinyao Zhu, Xin Jin, Chunhua Shi, Dan Chen
Summary: This study investigated a Rossby wave breaking (RWB) event and its impact on stratosphere-troposphere exchange (STE) over the Tibetan Plateau in mid-March 2006, using reanalysis data, satellite observations of ozone concentration, and a Lagrangian trajectory simulation. The results showed that the amplified amplitude of the Rossby wave due to increased eddy heat flux from the subtropical westerly jet contributed to the occurrence of the cyclonic RWB event. The cyclonic motion of the isentropic potential vorticity cut the tropical tropospheric air mass into the extratropical stratosphere, completing the stratosphere-troposphere mass exchange.
Article
Geosciences, Multidisciplinary
Yueyue Yu, Xueting Yu, Zhaoyong Guan, Dingzhu Hu, Chunhua Shi, Dong Guo, Jian Rao
Summary: This study categorizes the cold air outbreak (CAO) events over mid-latitudes of Eurasia (CAO_EA) and North America (CAO_NA) into those coupled with and those decoupled with stratospheric poleward warm airmass transport (PULSE) events. The findings show that the predictability of CAOs can be improved by predicting the stratospheric variability. In addition, a warm phase of the El Nino-Southern Oscillation (ENSO) in winter favors a higher coupling rate of CAO_NA and CAO_EA, while a phase transition of ENSO from the previous winter to the current winter is closely related to the interannual changes of the CAO coupling rate.
FRONTIERS IN EARTH SCIENCE
(2023)
Article
Meteorology & Atmospheric Sciences
Irina Statnaia, Alexey Karpechko, Matti Kamarainen, Heikki Jarvinen
Summary: In this study, we investigate the impact of the stratosphere on the predictability of Eurasian cold-spell events. We find that when the stratospheric polar vortex is weak, the predictability of cold spells is extended by 3-5 days compared to when the vortex is strong. We also show that this extended predictability can be captured by a simple statistical model.
QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY
(2022)
Article
Environmental Sciences
Su Jiang, Guitao Shi, Jihong Cole-Dai, Chunlei An, Bo Sun
Summary: The study found a latitudinal trend in perchlorate concentrations in different environments, influenced by populated areas and southern mid-high latitudes. Perchlorate in aerosols is not efficiently transported over long distances and is mainly localized near the landmasses. In the southern high latitudes, higher perchlorate concentrations in March may be caused by stratospheric inputs, while seasonal differences in main atmospheric sources may contribute to higher concentrations in the warm half of the year.
ENVIRONMENT INTERNATIONAL
(2021)
Article
Geosciences, Multidisciplinary
Juan J. Gonzalez-Aleman, Christian M. Grams, Blanca Ayarzaguena, Pablo Zurita-Gotor, Daniela I. Domeisen, Inigo Gomara, Belen Rodriguez-Fonseca, Frederic Vitart
Summary: We investigate the impact of sudden stratospheric warmings (SSWs) on the troposphere and their predictability limits through the study of the 2018 SSW event. The study finds that dynamical tropospheric events, consisting of two cyclogenesis events, were the main reasons for the predictability barriers in the prediction of negative NAM/NAO anomalies reaching the surface. This work sheds light on the stratosphere-troposphere coupling and the individual synoptic events that can hinder predictability during the downward impact of SSW events.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geosciences, Multidisciplinary
T. Kaluza, D. Kunkel, P. Hoor
Summary: This study analyzes the occurrence of turbulence in the North Atlantic during winter using aircraft observations and reanalysis data. The research reveals a sharp unimodal distribution of turbulence, with the peak occurring just below the tropopause. Turbulence also has a significant impact on the first 2 km above the tropopause.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Meteorology & Atmospheric Sciences
Ke Wei, Jiao Ma, Wen Chen, Pavel Vargin
Summary: Three-dimensional planetary wave analysis provides insights into the dynamic interactions between the stratosphere and troposphere, with interactions between different wavenumbers of planetary waves affecting the spatial distribution of wave flux. The strength of the stratospheric polar vortex is intricately related to the 3D wave flux, with complex correlations observed, while variations in wave flux are associated with the Arctic Oscillation and Scandinavian wave train pattern, influencing climate anomalies across the Northern Hemisphere.
Article
Geosciences, Multidisciplinary
ShuYang Yu, Jian Rao, Dong Guo
Summary: The tropospheric impact of Arctic ozone loss events is still debated. In this study, the researchers used ERAS reanalysis data and a climate-chemistry coupled model to investigate the frequency and effects of these events. The results suggest that Arctic ozone loss events are accompanied by increased total ozone in midlatitudes and a concurrent and delayed warming of the near surface over the Arctic and its neighboring areas.
EARTH AND PLANETARY PHYSICS
(2022)
Article
Meteorology & Atmospheric Sciences
Qian Lu, Jian Rao, Chunhua Shi, Dong Guo, Ji Wang, Zhuoqi Liang, Tian Wang
Summary: This study investigates the impact of stratospheric states on the subseasonal variability of local PM2.5 in the Beijing-Tianjin-Hebei (BTH) region. The results demonstrate that the subseasonal variation of PM2.5 concentration is significantly enhanced during sudden stratospheric warming (SSW) events. Different weather conditions play a crucial role in the accumulation and dispersion of pollutants during different phases.
ADVANCES IN ATMOSPHERIC SCIENCES
(2022)
Article
Meteorology & Atmospheric Sciences
Zhuoqi Liang, Jian Rao, Dong Guo, Qian Lu
Summary: This study utilized the CESM2-WACCM model to conduct multiple scenario experiments to explore the simulation and impact of SSW on the near surface. The effects of displacement SSW and split SSW show different trends in short and long lags in all CO2 increase experiments. Future projections indicate a potential expansion of the cold pattern over North Eurasia following displacement SSW and an enhancement of cold anomalies over North America following splits.
Article
Meteorology & Atmospheric Sciences
Jian Rao, Chaim I. Garfinkel, Tongwen Wu, Yixiong Lu, Min Chu
Summary: Progress and persistent biases in the simulation of the stratospheric polar vortex from three generations of CMIPs are assessed. It is found that the stratospheric cold bias is largest in CMIP3, but is improved in CMIP5 and CMIP6. Furthermore, most models exhibit some common biases, with intermodel spread in some parameters highly correlated with the SST bias in northern tropical oceans.
JOURNAL OF CLIMATE
(2022)
Article
Meteorology & Atmospheric Sciences
Zhuoqi Liang, Jian Rao, Dong Guo, Qian Lu, Chunhua Shi
Summary: It is found that changes in the Arctic stratospheric polar vortex have a significant influence on the extratropical troposphere in the mid-to-high latitudes of the Northern Hemisphere. Different states of the polar vortex result in various behaviors of tropospheric circulation and near surface climate, and are also related to different tropospheric teleconnections.
Article
Meteorology & Atmospheric Sciences
Dvir Chwat, Chaim Garfinkel, Wen Chen, Jian Rao
Summary: The predictability of Northern Hemisphere SSW events was investigated using 10 S2S forecast models. Four factors, including a preconditioned vortex, active Madden-Julian Oscillation, Quasi-Biennial Oscillation phase, and vortex morphology, were found to distinguish SSWs with higher predictability. Although the effects were not statistically significant at the individual level, they collectively explained 40% of the inter-event spread in SSW predictability.
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
(2022)
Article
Meteorology & Atmospheric Sciences
Jian Rao, Tongwen Wu, Chaim Garfinkel, Jingjia Luo, Yixiong Lu, Min Chu, Jinggao Hu
Summary: The possible impact of the stratospheric polar vortex on East Asian spring rainfall is assessed, and the representation of this effect in seasonal forecast models is evaluated. The models have some skill in forecasting the strength of the stratospheric polar vortex, but show a wide spread in predicting East Asian spring rainfall, possibly due to the underrepresentation of the linkage between the vortex and rainfall. The models can forecast the dry impact on Southeastern China, but fail to capture the wet impact on Korea and Japan.
Article
Geosciences, Multidisciplinary
Jian Rao, Chaim I. I. Garfinkel, Tongwen Wu, Jing-Jia Luo, Yixiong Lu, Min Chu, Qian Lu
Summary: The prediction of regional precipitation anomalies in East Asia is more difficult for seasonal forecasting models than for the large-scale drivers of these anomalies. These large-scale drivers include sea surface temperature anomalies and conditions in the polar stratosphere. A maximum covariance analysis is used to identify the patterns of sea surface temperature and stratospheric circulation that are most associated with abnormal precipitation in East Asia, and these patterns are used to correct seasonal forecasts. The correction of seasonal forecasts using the observed linkage between stratosphere-tropical ocean modes and East Asian rainfall improves the nonuniform predictability of rainfall in East Asia.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Meteorology & Atmospheric Sciences
Jian Rao, Chaim I. Garfinkel, Rongcai Ren, Tongwen Wu, Yixiong Lu
Summary: Using 25 models, this study explores the Southern Hemisphere's response to the quasi-biennial oscillation (QBO). The observed weakening of the polar vortex in the austral spring is qualitatively reproduced by seven models. These models also simulate enhanced upward propagation of waves from the Southern Hemisphere midlatitude troposphere. However, there are large biases in the simulation of the Brewer-Dobson circulation response among the models.
JOURNAL OF CLIMATE
(2023)
Article
Meteorology & Atmospheric Sciences
Jian Rao, Jin Xie, Yong Cao, Suxing Zhu, Qian Lu
Summary: This study compares two rainstorms that occurred in Henan Province, China in July 2021 and August 1975. The analysis of reanalysis data and precipitation observations reveals differences in rainfall characteristics, movement speed, and circulation patterns between the two events.
JOURNAL OF METEOROLOGICAL RESEARCH
(2022)
Article
Geosciences, Multidisciplinary
Yueyue Yu, Xueting Yu, Zhaoyong Guan, Dingzhu Hu, Chunhua Shi, Dong Guo, Jian Rao
Summary: This study categorizes the cold air outbreak (CAO) events over mid-latitudes of Eurasia (CAO_EA) and North America (CAO_NA) into those coupled with and those decoupled with stratospheric poleward warm airmass transport (PULSE) events. The findings show that the predictability of CAOs can be improved by predicting the stratospheric variability. In addition, a warm phase of the El Nino-Southern Oscillation (ENSO) in winter favors a higher coupling rate of CAO_NA and CAO_EA, while a phase transition of ENSO from the previous winter to the current winter is closely related to the interannual changes of the CAO coupling rate.
FRONTIERS IN EARTH SCIENCE
(2023)
Article
Meteorology & Atmospheric Sciences
Jian Rao, Chaim I. Garfinkel, Rongcai Ren, Tongwen Wu, Yixiong Lu, Min Chu
Summary: This study examines the projected Southern Hemisphere extratropical response to the quasi-biennial oscillation (QBO) using 20 models. The models simulate the deceleration of circumpolar westerlies during easterly QBO in the historical climate. The study also predicts changes in the stratospheric wind, subtropical jet, tropical easterlies, and wave activity in future scenarios.
JOURNAL OF CLIMATE
(2023)
Article
Environmental Sciences
Huidi Yang, Jian Rao, Haohan Chen, Qian Lu, Jingjia Luo
Summary: The lagged relationship between Kara-Barents sea ice and summer precipitation in eastern China is evaluated for Chinese models participating in phase 6 of the Coupled Model Intercomparison Project. Most Chinese CMIP6 models successfully simulate the variability and climatology of the sea ice in the Arctic. The dipole rainfall structure related to Kara-Barents sea ice variability is simulated with different degrees of success.
Article
Environmental Sciences
Haohan Chen, Jian Rao, Huidi Yang, Jingjia Luo, Gangsen Wu
Summary: This study evaluates the performance of multiple models from CMIP6 in simulating the relationship between Barents-Kara sea ice and rainfall in eastern China. Most models can simulate Arctic sea ice coverage, but only a few can reproduce the observed rainfall dipole pattern. The study suggests that the linkage between Arctic sea ice variability and China rainfall is mediated by the stratosphere, and only a few models exhibit a realistic interannual relationship.
Article
Meteorology & Atmospheric Sciences
Haoxiang Wang, Jian Rao, Dong Guo, Yixiong Lu, Yimin Liu
Summary: The El Nino-Southern Oscillation (ENSO) and Quasi-Biennial Oscillation (QBO) have individual and combined impacts on the northern winter stratospheric polar vortex. The joint effects of ENSO and QBO result in weakened polar vortex in El Nino-easterly QBO and strengthened polar vortex in La Nina-westerly QBO composites. The observed joint ENSO and QBO signals in the Arctic stratosphere are mostly a linearly superposed combination, and the interference of ENSO and QBO's impacts is also observed in the tropospheric circulation and tropical convections.
