Ruonan Zhang

Fudan University · Institute of Atmospheric Sciences

Li's previous study found a one‐to‐two correspondence relationship between the total solar irradiance (TSI) and monthly anomalies of the Ural atmospheric circulation during winter months. This relationship roughly meets the so‐called supercritical pitchfork bifurcation model, hence termed a pitchfork‐like (PL) relationship. Here, we extend this stu...

Plain Language Summary Stratospheric polar vortex (SPV) stretching events are characterized by a zonally asymmetric pattern of lower stratospheric variability with positive height anomalies over northern Eurasia and negative anomalies over Canada. In this study, we mainly focus on the SPV stretching events that occurred from October to November, an...

The weak stratospheric polar vortex (SPV) is usually linked to Northern Hemisphere cold spells. Based on the fifth generation of ECMWF atmospheric reanalysis and WACCM model experiments, we use K-means cluster analysis to extract the zonally asymmetric pattern of October-February stratospheric variability, which involves a stretched SPV and hence l...

This study investigates the stratospheric response to Arctic sea ice loss and subsequent near-surface impacts by analyzing 200-member coupled experiments using the Whole Atmosphere Community Climate Model version 6 (WACCM6) with preindustrial, present-day, and future sea ice conditions specified following the protocol of the Polar Amplification Mod...

Plain Language Summary Central Eurasia has experienced more frequent cold winters and extreme weather events in recent years. Many mechanisms have been proposed for the frequent occurrence of freezing winters. Both observational and modeling studies suggested that the rapid sea‐ice decline has influenced the increase in cold temperature events. Mel...

Observed winter near-surface air temperature anomalies in the Northern Hemisphere have exhibited a warm Arctic-cold Eurasia (WACE) pattern with interdecadal variation in recent decades, but the exact mechanism behind WACE is still under debate. This study used reanalysis data and climate model simulations to investigate the interdecadal variability...

Widespread observed and projected increases in warm extremes, along with decreases in cold extremes, have been confirmed as being consistent with global and regional warming. Here we disclosed that the decadal variation in the frequency of the surface air temperature (SAT) extremes over Siberia in winter was primarily dominated by the Atlantic Meri...

A sequence of extreme cold events occurred across Eurasia and North America during winter 2020/2021. Here, we explore the causes and associated mechanisms for the extremely cold temperatures using both observations and large-ensemble simulations. Experiments were conducted with observed ocean surface boundary conditions prescribed globally, and reg...

The leading mode of the atmospheric background flow over the North Atlantic–Arctic Ocean (i.e., 300-hPa meridional wind; V300-EOF1) exhibited notable decadal variations during 1979–2019, with intensified V300-EOF1 since the early-2000s. The modulation of the interdecadal change in the East Asian winter monsoon (EAWM) by the V300-EOF1 mode and its l...

In recent decades, the Barents Sea has warmed more than twice as fast as the rest of the Arctic in winter, but the exact causes behind this amplified warming remain unclear. In this study, we quantify the wintertime Barents Sea warming (BSW) with an average linear trend of 1.74℃/decade and an interdecadal change around 2003 from 1979 to 2019 based...

An unprecedented cold event occurred in Central and eastern Eurasia during the 2020/21 winter, including five episodes of consecutive cold spells (EP1–5). Through analysis of both observational and simulations, we show that the concurrent Arctic sea-ice loss and extratropical Pacific decadal oscillation (EPDO) warming are potential drivers for the...

Based on the Lagrangian particle dispersion model, HYSPLIT 4.9, this study analyzed the summertime atmospheric moisture sources and transportation pathways affecting six subregions across China. The sources were: Midlatitude Westerly (MLW), Siberian-Arctic regions (SibArc), Okhotsk Sea (OKS), Indian Ocean (IO), South China Sea (SCS), Pacific Ocean...

During the past few decades, Arctic sea-ice has declined rapidly in both autumn and winter, which is likely to link extreme weather and climate events across the Northern Hemisphere midlatitudes. Here, we use reanalysis data to investigate the possible linkage between mid–high-latitude atmospheric circulation and Arctic sea-ice loss in different ge...

北极具有独特的地理位置和战略地位，是当前全球变化研究的热点区域之一。北极增暖是全球平均值的两倍以上，被称为“北极放大”现象。在北极快速增暖背景下，冰冻圈尤其是海冰显著萎缩，对北极乃至中纬度天气气候产生深远影响。对北极快速增暖背景下冰冻圈主要要素（包括海冰、冰盖、冰川、积雪和冻土）时空变化特征及未来预估进行了综述，同时总结了海冰变化对北极气候系统（大气圈、水圈、岩石圈和生物圈）以及中纬度极端天气气候事件的影响。指出当前北极冰冻圈变化研究受观测资料缺乏及模式模拟不确定等问题限制，其机理及对中纬度天气气候影响机制仍存在争议。未来还需要加强北极地区的综合监测，提高模式对北极气候系统物理过程的模拟能力，进行多模式、多数据、多方法的集成研究。The Arctic has a unique geograp...

Plain Language Summary Declining sea‐ice is having profound impacts in the Arctic. Scientists are eager to work out if and how Arctic sea‐ice affects weather and climate in mid‐latitudes. Years with below‐average sea‐ice in the Barents‐Kara seas, which lie north of Norway and western Russia, tend to coincide with colder winters over Eurasia, and vi...

Warming amplification over the Arctic Pole (AP hereafter) and Third Pole (Tibetan Plateau, TP hereafter) can trigger a series of climate responses and have global consequences. Arctic amplification (AA) and Tibetan amplification (TA) are the most significant characteristics of climate change patterns over the two Poles. In this study, trends, mecha...

In recent decades, unprecedented extreme summer heat waves have occurred in Europe, and they have exhibited an increasing trend since 1970s1-4. Although previous studies have suggested that these recent hot European summers could have been instigated by the underlying surface thermal conditions, the possible influence of shrinking Arctic sea ice an...

An east-west dipole mode of winter Eurasian snow water equivalent (SWE) is found during the period of 1979-2015. It accounts for about 23.4% of the total variance, and displayed a significant decadal change in the early-2000s. The basin warming footprint of the North Atlantic likely exerted an influence on this decadal change, and the observation-b...

An anomalous “north-south” dipole mode of the snow water equivalent (SWE) persisting from winter to spring is detected over the Eurasian mid–to–high latitudes in this study. Using observational datasets and numerical experiments of the Community Atmospheric Model (5.0), we show that this mode contributes to prolonged winter–springtime coldness in m...

An anomalous “north-south” dipole mode of snow water equivalent (SWE) persisting from winter to spring is detected over the Eurasian mid–to–high latitudes in this study. We show that this mode plays a key role in modulating the prolonged winter–spring coldness in Eurasian mid-latitudes, and is linked closely to the declined November Arctic sea ice...

The influence of Arctic sea ice concentration (SIC) on the inter‐annual variations of the frequency of summertime Ural blocking (UB) during the period of 1980–2013 is investigated using observational and reanalysis data sets and version 5.0 of the Community Atmospheric Model. The results reveal that the variations in the UB frequency display a stat...

The relationship between Eurasian mid-high latitudes teleconnection in summer and the interannual variations of Arctic sea ice concentration (SIC) from preceding spring to summer and the associated influence on East Asian summer precipitation during the period of 1980–2015 are investigated by using NCEP/NCAR reanalysis datasets and the Community At...

The spring snow water equivalent (SWE) over Eurasia plays an important role in East Asian and Indian monsoon rainfall. This study evaluates the seasonal prediction capability of NCEP Climate Forecast System version 2 (CFSv2) retrospective forecasts (1983–2010) for the Eurasian spring SWE. The results demonstrate that CFSv2 is able to represent the...

Two dominant modes of the winter temperature over East Asia, a northern mode and a southern mode, and their links with Arctic climate conditions are analyzed. The relationships of the two modes with Arctic sea ice are different. The northern mode is closely linked to variations in sea ice of the Arctic Barents–Laptev Sea in previous autumn and most...

In this study, the relationship between Eurasian spring snow decrement (SSD) and East Asian summer precipitation and related mechanisms were investigated using observational data and the Community Atmospheric Model, version 3.1 (CAM3.1). The results show that a west-east dipole pattern in Eurasian SSD anomalies, with a negative center located in th...

Eurasian snow cover fraction (SCF) prediction is analyzed using the recently developed National Centers for Environmental Prediction (NCEP) Climate Forecast System version 2 (CFSv2) monthly retrospective forecasts for 1983–2009. The CFSv2 is generally capable of reproducing the observed Eurasian SCF seasonal cycle and climatology. This study focuse...

Two dominant modes of the winter temperature over East Asia, a northern mode and a southern mode, and their links with Arctic climate conditions are analyzed. The relationships of the two modes with Arctic sea ice are different. The northern mode is closely linked to variations in sea ice of the Arctic Barents–Laptev Sea in previous autumn and most...

Using observational data for 1979-2010, the temporal and spatial variations of wintertime (December-February) snow water equivalent (SWE) over China and their relations to the November SWE, wintertime snowfall, snow evaporation, sublimation and melting are investigated. The results revealed that the SWE is principally distributed in four snow regio...

In January 2013, a severe fog and haze event (FHE) of strong intensity, long duration, and extensive coverage occurred in eastern China. The present study investigates meteorological conditions for this FHE by diagnosing both its atmospheric background fields and daily evolution in January 2013. The results show that a weak East Asian winter monsoo...