Abstract This paper reviews progress in the study of Tibetan Plateau (TP) climate dynamics over past decade. Several theoretical frameworks, including thermal adaptation and TP sensible heat (SH) driving air-pump, have been developed to identify mechanisms responsible for circulation anomaly produced by forcing TP. Numerical simulations demonstrate that effects large-scale orography, Iranian Plateaus (TIP), are crucial formation East Asian South summer monsoons (SASM) because surface SH TIP...

Abstract Based on the NCEP–NCAR reanalysis dataset covering 1958–2012, this paper demonstrates a statistically significant relationship between occurrence of major stratospheric sudden warming events (SSWs) in midwinter and seasonal timing final (SFWs) spring. Specifically, early spring SFWs that average occur March tend to be preceded by non-SSW winters, while late take place up until May are mostly SSW midwinter. Though (absence) may not always followed (early) spring, there is much higher...

The stratospheric Arctic vortex (SAV) plays a critical role in forecasting cold winters northern mid-latitudes. Its influence on the tropospheric mid- and high-latitudes has attracted growing attention recent years. However, trend SAV during two decades is still unknown. Here, using three reanalysis datasets, we found that intensity 1998-2016 strengthening trend, contrast to weakening before period. Approximately 25% of this contributed by warming sea-surface temperature (SST) over central...

Abstract A major stratospheric sudden warming (SSW) event was observed in February 2018 after a 4‐year absence since the winter of 2013/2014. Based on reanalysis data, polar night jet changed from very strong state to moderate during 12–19 January, and westerlies directly reversed easterlies 5–15 February. The intensified East Asian trough, Alaskan blocking, U.S. trough amplified extratropical climatological wave 2, which propagated upward into stratosphere, leading vortex‐splitting SSW...

Abstract Using 25 quasi-biennial oscillation (QBO)-resolving models from phases 5 and 6 of the Coupled Model Intercomparison Project (CMIP5/6), this study systematically explores Southern Hemisphere (SH) extratropical response to QBO. The observed maximum stratospheric polar vortex–weakening 20-hPa easterly QBO appears in austral spring, which is reproduced qualitatively by seven models. Eliassen–Palm (EP) flux convergence associated with enhanced upward propagation waves SH midlatitude...

Monthly mean reanalysis data and numerical experiments based on a climate model are employed to investigate the relative impacts of different types diabatic heating their synthetic effects formation summertime subtropical anticyclones. Results show that strong land surface sensible (SE) west condensation (CO) east over each continent generate cyclones in lower layers anticyclones upper layers, whereas radiative cooling oceans generates lower-layer anticyclone upper-layer cyclone...

Abstract. This study investigates three types of atmospheric forcing across the summertime subtropics that are shown to contribute in various ways occurrence dry and wet climates subtropics. To explain formation desert over western parts continents monsoon eastern parts, we propose a new mechanism positive feedback between diabatic heating vorticity generation occurs via meridional advection planetary temperature. Monsoon demonstrated coexist as twin features multi-scale forcing, follows....

The upper-troposphere-temperature-maximum (UTTM) over South Asia is a pronounced feature in the Northern Hemisphere summer. Its formation mechanism still unclear. This study shows that latitude location of upper-tropospheric warm-center (T) coincides with subtropical anticyclone, and its longitude determined by zonal distribution vertical gradient heating/cooling (Q z = ∂Q/∂z), which different from Gill's model. Since both convective heating radiation cooling decrease height upper...

Abstract The El Niño–Southern Oscillation (ENSO) has significant effects on the extratropical stratosphere. This study explores nonlinearity and asymmetry of these influences by distinguishing different four types ENSO: “moderate Niño,” “strong La Niña,” Niña.” It is revealed that moderate Niño strong Niña are much more efficient than Niña, respectively, in modulating northern winter stratospheric variability, resulting asymmetry. tropical rainfall anomalies induced a or centered over...

Abstract This study investigates the dynamical linkage between meridional mass circulation and cold air outbreaks using ERA-Interim data covering period 1979–2011. It is found that onset date of continental-scale coincides well with peak time stronger events, when net transport across 60°N in warm or branch exceeds ~88 × 109 kg s−1. During weaker events below ~71.6 s−1, most areas midlatitudes are generally mild conditions except northern part western Europe. Composite patterns anomalies...

Abstract Long‐term simulations from the Community Earth System Model with Whole Atmosphere Climate (CESM‐WACCM) as its atmospheric component are used to investigate asymmetry and nonlinearity of influences El Niño–Southern Oscillation (ENSO) on northern winter stratosphere. As in Part 1 this study, four different types ENSO considered. The composite CESM‐WACCM results first confirm conclusions drawn observations, that stratospheric polar jet responses “moderate Niño” “strong La Niña”...

Abstract This study investigates dominant patterns of daily surface air temperature anomalies in winter (November–February) and their relationship with the meridional mass circulation variability using Interim ECMWF Re-Analysis 1979–2011. Mass indices are constructed to measure day-to-day transport into polar region by warm branch aloft out cold lower troposphere. It is shown that weaker airmass upper atmosphere accompanied equatorward advancement As a result, largely imprisoned within...

Using the CMIP5 multimodel ensemble (MME) historical experiments, modulation of stratospheric El Niño–Southern Oscillation (ENSO) teleconnection by Pacific decadal oscillation (PDO) is investigated in this study. Niño (La Niña) significantly impacts extratropical stratosphere mainly during positive (negative) PDO MME. Although composite tropical ENSO SST intensities are similar and negative models, Pacific–North American (PNA) responses only significant when phase. The local anomalies North...

Abstract Previous studies have reported that the predictive limit of stratospheric sudden warming (SSW) events in Beijing Climate Center forecast system (BCC_CSM) is shorter than 2 weeks. This study continues to analyze general characteristics this model forecasting SSWs and carries out a trial error corrections. The ratio ensemble members zonal wind reversal with 5‐day delay allowed (hit ratio) higher for SSW small decrease mean winds (moderate SSWs) large (radical hindcasts initialized...

Abstract This paper reports that there has been a significant relationship between the quasi‐biennial oscillation (QBO) in zonal wind at 50 hPa summer and precipitation August northern China since late 1970s. The correlation coefficient them reaches up to −0.61 during 1979–2018. Associated with easterly (westerly) phase of QBO, is meridional dipole pattern from stratosphere troposphere over Northwest Pacific anomalies 25–50°N westerly (easterly) 50–65°N. zonal‐wind favors strengthening...

Using the ERA5 reanalysis, sea surface temperature, ice observations, and real-time multivariate Madden-Julian Oscillation (MJO) index, evolution of stratospheric extreme circulation in winter 2022/2023 is explored. The polar vortex was disturbed three times 2022/23 winter, contrasted with only one disturbance during other recent winters an SSW. Possible favorable conditions for strong disturbances their effects on ozone, water vapor distribution, near-surface temperature were examined....

Abstract Extreme weather events such as cold-air outbreaks (CAOs) pose great threats to human life and the socioeconomic well-being of modern society. In past, our capability predict their occurrences has been constrained by 2-week predictability limit for weather. We demonstrate here first time that a rapid increase air mass transported into polar stratosphere, referred pulse stratosphere (PULSE), can often be predicted with useful degree skill 4–6 weeks in advance operational forecast...

Abstract Using the daily ERA‐Interim reanalysis data set for 32 winters in 1979–2011, we find that midlatitude cold air outbreaks (CAOs) tend to preferentially occur within a week after simultaneously stronger mass circulations into Arctic region upper levels and out of below. The relationship CAOs with Oscillation (AO) is less robust because temporal changes AO are resulted from small imbalance between poleward equatorward branches circulation. Results indicate only when branch leads (44%...

Abstract Using 20 quasi-biennial oscillation (QBO)-resolving models from phases 5/6 of the Coupled Model Intercomparison Project (CMIP5/6), this study examines projected Southern Hemisphere (SH) extratropical response to QBO. Nine 22 simulate decelerated circumpolar westerlies during easterly QBO (EQBO) in historical climate as is observed, though only ∼30% observed change reproduced multimodel ensemble mean (MME) these high-skill models. These project an enhanced stratospheric...