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Utilizing the Community Atmosphere Model, version 4, the influence of Arctic sea-ice concentration (SIC) on the extended-range prediction of three simulated cold events (CEs) in East Asia is investigated. Numerical results show that the Arctic SIC is crucial for the extended-range prediction of CEs in East Asia. The conditional nonlinear optimal perturbation approach is adopted to identify the optimal Arctic SIC perturbations with the largest influence on CE prediction on the extended-range time scale. It shows that the optimal SIC perturbations are more inclined to weaken the CEs and cause large prediction errors in the fourth pentad, as compared with random SIC perturbations under the same constraint. Further diagnosis reveals that the optimal SIC perturbations first modulate the local temperature through the diabatic process, and then influence the remote temperature by horizontal advection and vertical convection terms. Consequently, the optimal SIC perturbations trigger a warming center in East Asia through the propagation of Rossby wave trains, leading to the largest prediction uncertainty of the CEs in the fourth pentad. These results may provide scientific support for targeted observation of Arctic SIC to improve the extended-range CE prediction skill. [ABSTRACT FROM AUTHOR]

Different from previous studies that mainly focused on the influences of large-scale horizontal circulation on cold events, this paper used the three-type decomposition of the global atmospheric circulation (3P-DGAC), taking the winter of 2021/22 as an example, to investigate the synergistic effects of the local horizontal, meridional and zonal circulations in the cold events of East Asia (EA). We discovered that the large-scale horizontal circulations influencing the two cold events in November and December are typically characterized by a transverse trough turning to a vertical trough, with the northwest path of cold air source in November and the hyperpolar path in December. But for the two consecutive cold events in February, the horizontal circulations are characterized by unstable small trough development, corresponding to small cold air masses splitting southward. Besides, with the development of the trough and ridge system of horizontal circulation, the local clockwise meridional circulation anomalies in the mid-latitude EA are promoted. The strong surface north winds of the meridional circulation anomaly could promote the southward movement of Arctic cold air, leading to the cooling of EA. Due to the presence of updrafts in front of the trough behind the ridge and downdrafts behind the trough in front of the ridge, the local zonal circulation anomalies in northern EA may connect with the East Asian trough (EAT) and the Ural Blocking (UB), which further cause the formation and development of cold events. In addition to the horizontal circulation analyzed in previous studies, this study demonstrated that vertical circulations also played important roles in the outbreak of cold events. Large-scale three-dimensional (3D) circulations work synergistically to affect the accumulation and southward movement of cold air. Our application of 3P-DGAC provides a new idea to analyze the dynamic effects of 3D circulations influencing cold events. • During the winter of 2021/22, East Asia (EA) was hit by four cold events, and the large-scale horizontal circulation served as an important bridge between the cold air and EA. • The local meridional and zonal circulation anomalies both contributed to the transport of cold air and the enhancement of surface high pressure. • Large scale three-dimensional circulations could work synergistically to affect the accumulation and southward movement of cold air. [ABSTRACT FROM AUTHOR]

Human mobility can be considered an effective adaptation strategy in response to environmental risks, given that adverse environmental conditions are often temporary and in-situ adaptation may not always be feasible or desirable. Despite its importance, the concept of short-term mobility as a behavioral response to environmental hazards has been understudied in geographies of health and place and behavioral economics. For a comprehensive understanding of how everyday mobilities are used as a risk adaptation strategy, this study avails of a multiscalar approach's ability to examine the influences of air pollution and extreme cold events on origin-destination movements. The modifiable areal unit problem (MAUP) and modifiable temporal unit problem (MTUP) are analyzed. The results suggest that the scale effects of the MAUP and MTUP are evident from the variations in regression coefficients of the differences in air quality and extreme cold events between origin and destination units. It is also found that the prefecture-level units that include both urbanized city proper and rural countryside, are not an ideal spatial analysis scale. Furthermore, this study reveals that the nexus of air quality differences and short-term movements is significantly impacted by changes in temporal scales. Our results offer fresh evidence on the decision-making process underlying mobility as an adaptation strategy to air pollution and cold events. • We examine hazard-induced mobility patterns at multiple spatial and temporal scales. • The scale effects of MAUP and MTUP are evident for air pollution and cold events. • The prefecture level units are not an ideal spatial analysis scale. • The nexus of air quality and short-term movements is impacted by temporal scales. [ABSTRACT FROM AUTHOR]

Coastal tide pools in southern Japan are inhabited by the rock-boring sea urchin Echinostrephus molaris, which excavate pits in the substrate. These pits are subsequently used by non-boring sea urchins such as Anthocidaris crassispina and Echinometra sp. B, and the recolonized pits are often inhabited by a commensal limpet-like trochid snail species, Broderipia iridescens. We explored the population and community dynamics of these sea urchins and the limpet-like snail by monitoring occupancy of 512 pits in tide pools in Shirahama, Japan from May 2017–May 2019. Initially, nearly all pits were occupied by any one of the three sea urchin species, but an unusual cold event in February 2018 caused a mass die off of these sea urchins. After this event, occupancy decreased from 99% to 15%, and the tropical species Echinometra sp. B disappeared from the study pools. We observed slow population recovery of E. molaris and A. crassispina, provably via migration of sub-adults from the subtidal zone. Turnover rate of the pit-occupying sea urchin species was <1.0% before the cold event, but drastically increased after the cold event. Population size of the commensal snail decreased along with those of their host, but the rate of commensalism was constant at 50–55% throughout the study period, suggesting that these snails followed their host sea urchins repeating inter-pit migration. Despite mass mortality and slow recovery, the sea urchin density remained high enough to maintain persistent sea urchin barrens throughout the study period. [ABSTRACT FROM AUTHOR]

Aim: To investigate some of the environmental variables underpinning the past and present distribution of an ecosystem engineer near its poleward range edge. Location: >500 locations spanning >7,400 km around Ireland. Methods: We collated past and present distribution records on a known climate change indicator, the reef‐forming worm Sabellaria alveolata (Linnaeus, 1767) in a biogeographic boundary region over 182 years (1836–2018). This included repeat sampling of 60 locations in the cooler 1950s and again in the warmer 2000s and 2010s. Using species distribution modelling, we identified some of the environmental drivers that likely underpin S. alveolata distribution towards the leading edge of its biogeographical range in Ireland. Results: Through plotting 981 records of presence and absence, we revealed a discontinuous distribution with discretely bounded sub‐populations, and edges that coincide with the locations of tidal fronts. Repeat surveys of 60 locations across three time periods showed evidence of population increases, declines, local extirpation and recolonization events within the range, but no evidence of extensions beyond the previously identified distribution limits, despite decades of warming. At a regional scale, populations were relatively stable through time, but local populations in the cold Irish Sea appear highly dynamic and vulnerable to local extirpation risk. Contemporary distribution data (2013–2018) computed with modelled environmental data identified specific niche requirements which can explain the many distribution gaps, namely wave height, tidal amplitude, stratification index, then substrate type. Main conclusions: In the face of climate warming, such specific niche requirements can create environmental barriers that may prevent species from extending beyond their leading edges. These boundaries may limit a species' capacity to redistribute in response to global environmental change. [ABSTRACT FROM AUTHOR]

Southern China was hit by a severe cold event during January 21–25, 2016, characteristic of a drastic and sudden temperature drop, with new records of low temperatures set in widespread areas. This cold event was dynamically linked to the activity of the Arctic oscillation (AO) whose evolution led the event by about 2 weeks. Different from this short lasting but intense cold event in 2016, another cold event in the 2008 winter lasted much longer and occurred in tandem with freezing precipitation. Their differences in the duration and precipitation are essentially determined by differing behaviours of blocking highs at mid–high latitudes, the India–Burma Trough and the western Pacific subtropical high. The rapid southward invasion of cold air masses during the 2016 event resulted from the rapid decay of the blocking high, which emanated wave energies downstream and likewise lost wave energies to the local mean flow. By contrast, during the 2008 cold event, continuous upstream wave energy dispersion recurrently stimulated disturbances in the blocking domain, which then extracted energies from the mean flow efficiently to survive markedly longer. Moreover, in the 2008 case, the deepening of the India–Burma Trough and the westward extension of the western Pacific subtropical high jointly enhanced the moisture transport, leading to the freezing rain. This favourable configuration for precipitation was absent in the 2016 case, dictating its dry nature accordingly. [ABSTRACT FROM AUTHOR]

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Mangrove forests growing at the poleward edges of their geographic distribution are occasionally subject to freezing (0 °C) events. Cold wave effects on mangrove trees are well documented and adaptation to cold stress has been reported for local mangrove populations in the North Atlantic. However, there is less understanding of effects of cold waves on mangroves in the northern Pacific, especially at the regional scale. Moreover, it is unclear if cold tolerant mangrove species of North Asia display variation in resistance to cold temperatures across their geographic distribution. Using a cold wave event that occurred in January 2021, we evaluated the effects of low temperatures on vegetation index (VI) change (relative to a recent five-year baseline) for mangrove forests dominated by Kandelia obovata (Rhizophoraceae) and Avicennia marina (Acanthaceaee) at the northern edge of their geographical range. We used two VIs derived from Sentinel-2 imagery as indicators for canopy health: the normalized difference infrared index (NDII) and the chlorophyll red-edge index (ChlRE), which reflect forest canopy water content and chlorophyll concentration, respectively. We isolated the cold wave effects on the forest canopy from phenology (i.e., cold wave induced deviation from a five-year baseline) and used multiple linear regression to identify significant climatic predictors for the response of mangrove forest canopy VI change to low temperatures. For areas where the cold wave resulted in temperatures K. obovata stands in the northern Pacific, and in congruence with findings from New World mangroves, they imply geographic variation in mangrove leaf physiological resistance to cold for Northern Pacific mangroves.

This study investigates the late Quaternary glacial history of the Cogarbu valley on the northern slopes of the Bhutanese Himalaya using 10Be surface exposure dating. Five major glacial events were constrained based on 28 10Be exposure ages. The equilibrium line altitude (ELA) of the oldest and most extensive glacial event (M5–M9) is ∼489 m lower than the present, followed by four other events (M4, M3, M2 and M1) with ELA depressions of ∼452, ∼200, ∼76 and ∼42 m, respectively. The exposure ages of the oldest glacial event (M5–M9) are ∼23.4–19.1 ka, corresponding to the global Last Glacial Maximum (gLGM). The second (M4, ∼15.8 ka) and the third oldest events (M3, ∼11.5 ka) coincide with the Heinrich‐1 and Younger Dryas event, respectively. The fourth oldest glacial event (∼1.2–0.82 ka) occurred during the Late Holocene. The latest glacial event (∼0.77–0.53 ka) represents the Little Ice Age glacial advances. These glacial events are broadly synchronous with those from other regions across the monsoon‐influenced Himalaya. All these events occurred during the cold periods, despite relatively dry conditions. It appears that temperature is the major factor driving glacial fluctuations since the gLGM in the Bhutanese Himalaya. [ABSTRACT FROM AUTHOR]

The dramatic expansion of rubber plantations in mainland South-East Asia and south-west China has caused many eco-environmental problems, especially negative hydrological consequences. These problems have gradually worsened and pose formidable threats to rubber agriculture, especially in the light of increasingly frequent extreme weather events. Although rubber-based agroforestry systems are regarded as the best solution for improving the sustainability of rubber agriculture and environmental conservation, plant water use and related interactions have rarely been examined in such systems., We primarily used stable isotope (δD, δ18O and δ13C) methods to test whether intercropping could improve the water use and extreme weather tolerance (extreme cold and drought in our study) of rubber trees in three types of promising agroforestry systems (i.e. rubber with tea, coffee and cocoa) in Xishuangbanna, China., We found that the rubber tree is a drought-avoidance plant with strong plasticity with respect to water uptake. This characteristic is reflected by its ability to cope with serious seasonal drought, allowing it to avoid interspecific competition for water. The rubber trees showed wasteful water behaviour unless they were intercropped with tea or coffee. However, these intercropped species exhibited drought-tolerance strategies and maintained lower water use efficiencies to strengthen their competitive capacity for surface soil water. The stable δ13C values of the intercrop leaves indicated that all the agroforestry systems have stable internal microclimatic environments or higher resistance., Synthesis and applications. This study suggests that interspecific competition for water can enhance the water use efficiency of drought-avoidance plants (i.e. rubber trees) and lead to complementarity between the root distributions of plants in rubber agroforestry systems (i.e. rubber with tea, coffee and cocoa). All agroforestry systems have higher resistance, but tea was the most suitable intercrop in terms of water use because the interspecific competition for water was moderate and the agroforestry system retained much more soil water and improved the water use efficiency of the rubber tree. Considering the root characteristics of the tea trees, we suggest that the crops selected for intercropping with rubber trees should have a relatively fixed water use pattern, short lateral roots and a moderate amount of fine roots that overlap with the roots of the rubber trees in the shallow soil layer. [ABSTRACT FROM AUTHOR]

Abstract The frequency, duration, and intensity of extreme cold events are widely regarded as primary constraints on the upper latitudinal limits of mangroves. Little data are available on the consequences of recovery (or lack thereof) of non‐floristic components of mangrove ecosystems after a disturbance caused by cold weather. An unusually severe cold wave occurred in southern China in January 2008. The impact of this cold event and the subsequent recovery of mollusks in a Rhizophora stylosa mangrove forest in southern China were evaluated over a 3‐yr study from April 2007 to January 2010. The cold event caused significant mortality of mollusks, which was rapidly followed by an increase in the populations of opportunistic species, and then their subsequent collapse within 6 months. Comparison with data collected in April 2007 (before the cold event) revealed that the density, biomass, and species richness of mollusks decreased by 87.5%, 80.6%, and 56.3%, respectively, except for a transient and compensatory increase in the numbers of benthic mollusks (by 47.5%). Arboreal mollusks were more sensitive to the cold event than benthic species, but both groups showed similar recovery trajectories. After 21 months, the density, biomass, and richness of mollusk species still remained 9.4%, 13.2%, and 26.2% lower than pre‐event. Full recovery took more than 24 months. In comparison to mangrove vegetation, mollusks inhabiting mangroves appeared to be more vulnerable to cold events, but also recovered faster. In conclusion, it took more than 2 yr for the species richness of mollusks to recover from the cold event, and the rate of recovery was slower for the arboreal type.

The frequency, duration, and intensity of extreme cold events are widely regarded as primary constraints on the upper latitudinal limits of mangroves. Little data are available on the consequences of recovery (or lack thereof) of non-floristic components of mangrove ecosystems after a disturbance caused by cold weather. An unusually severe cold wave occurred in southern China in January 2008. The impact of this cold event and the subsequent recovery of mollusks in a Rhizophora stylosa mangrove forest in southern China were evaluated over a 3-yr study from April 2007 to January 2010. The cold event caused significant mortality of mollusks, which was rapidly followed by an increase in the populations of opportunistic species, and then their subsequent collapse within 6 months. Comparison with data collected in April 2007 (before the cold event) revealed that the density, biomass, and species richness of mollusks decreased by 87.5%, 80.6%, and 56.3%, respectively, except for a transient and compensatory increase in the numbers of benthic mollusks (by 47.5%). Arboreal mollusks were more sensitive to the cold event than benthic species, but both groups showed similar recovery trajectories. After 21 months, the density, biomass, and richness of mollusk species still remained 9.4%, 13.2%, and 26.2% lower than pre-event. Full recovery took more than 24 months. In comparison to mangrove vegetation, mollusks inhabiting mangroves appeared to be more vulnerable to cold events, but also recovered faster. In conclusion, it took more than 2 yr for the species richness of mollusks to recover from the cold event, and the rate of recovery was slower for the arboreal type. [ABSTRACT FROM AUTHOR]

After decomposing an atmospheric field into climatic and anomalous components, a maximum height anomaly (MHA) in upper troposphere is found to be closely associated with surface anomalous temperature episodes. Thus, a unified method has been proposed to trace both heat and cold events as well as surface temperature anomalies through the following four aspects of this study. (1) First, a global daily MHA database from 1980 to 2010 is derived and its long-term variation is analyzed. (2) The general relationship between surface air temperature anomaly (SATA) and MHA is then studied. Following the hydrostatic balance, positive (negative) MHA center often corresponds well to positive (negative) SATA or heat (cold) event. (3) Potential capability of using MHA signal to extend predictability of SATA events is further examined. It is found that signals in MHA are stronger and appear earlier than that in temperature field. Positive or negative MHA centers can often be traced 9 days ahead on average for many SATA events. The earliest MHA signal to indicate a heat (cold) event can be traced 20 (26) days back in an upstream region. (4) Some challenges in applying MHA to early warning SATA events are discussed, mainly from the irregularity of MHA tracks, the location uncertainty of downward extension of upper air temperature anomaly including missing and false alarm issue, and the inability in quantifying intensity. Therefore, the forecast capability of MHA signal will strongly depend on the quality of an operational model forecasts. [ABSTRACT FROM AUTHOR]

There are different viewpoints on the paleoclimatic significances of peat humification in different regions. Alkali extracting solution absorbance method was used to measure the peat humification in Hani of Northeast China. Combined with 14C dating data for chronological framework, the proxy climate indicators of peat humification in Hani of Northeast China, Dajiuhu of Shennongjia, Hongyuan of Qinghai-Tibet Plateau and Tianhushan of Fujian were compared, and the reasons for similarities and differences on the paleoclimatic significance of peat humification in different regions were analyzed. The results show that the paleoclimatic significance of peat humification in Hani includes temperature-humidity combination, and the higher humification indicates warm and humid climate, the lower humification indicates dry and cold climate; according to the comparison of peat humification temporal series in Hani, Hongyuan, Dajiuhu and Tianhushan, although the paleoclimatic significances are different, but the evolution trends of Holocene paleoclimate environment recorded are almost the same; the records include warming in Early Holocene, megathermal in Middle Holocene and cooling in Late Holocene; the effects of temperature, humidity, monsoon, latitude and longitude and geological landform on peat humification are significant, but the hydrothermal conditions are direct, and the other factors are in direct; it is different to explain the paleoclimatic significances of peat humification in different regions, and the location, geological landform, average annual temperature, monsoon, precipitation and vegetation should be considered. [ABSTRACT FROM AUTHOR]

This paper is a review of studies of abrupt climate changes (ACCs) during the Holocene published during the past ten years. North Atlantic cold events are indicators of ACCs. As indicated by North Atlantic ice-rafted debris (IRD), there were nine confirmed cold events during the Holocene, occurring at 11.1 kyr, 10.3 kyr, 9.4 kyr, 8.1 kyr, 5.9 kyr, 4.2 kyr, 2.8 kyr, 1.4 kyr, and 0.4 kyr respectively according to most representative results from Bond et al. (1997). However, the identification of chronology has been made with some uncertainties. Considerable climatic proxy data have shown that, during the cold events, substantial climate abnormalities have occurred widely across the globe, particularly in the areas surrounding the North Atlantic. These abnormalities were in the form of high-latitude cold in the both hemispheres, expansion of the Westerlies to low latitudes, drought in the monsoon regions, recession of summer monsoons, and intensification of the winter monsoons. Studies have indicated that the four ACCs occurring in the early Holocene may be related to freshwater pulses from ice melting in the northern part of the North Atlantic, and the other five ACCs that occurred during the middle and late Holocene may be related to the decreased solar activity. [ABSTRACT FROM AUTHOR]

Pollen record of an AMS radiocarbon dated lacustrine sediment profile underlying the Chandra peat deposit in Himachal Pradesh, yielded signatures of the globally reported Younger Dryas (YD) cold event. This report of the YD event in NW Himalaya, substantiated by mineral magnetic variations, also records significant wet and warm conditions prior to 12,880 cal yrs BP, depicting the Ållerød interstadial preceding YD. The notable decrease in local (meadow) and regional (desert steppe) vegetation indicates major climate shift towards cold and dry conditions marking the onset of YD that intensified progressively till 11,640 cal yrs BP. The YD terminates with gradual reappearance of local and regional flora, indicating initiation of the Holocene wet and warm conditions. The pollen-inferred floristic changes and mineral magnetic variations suggest that in NW Himalaya the initiation and termination of the YD cold event was probably gradual. [ABSTRACT FROM AUTHOR]

The article presents a study on the daily scale variation of Eurasian pattern (EU) and its connection to winter weather over East Asia. It states that winter surface air temperature in East Asia is negatively correlative with a wave pattern over the Eurasian continent, called EU. It avers that a new definition of the EU index (EUw) was proposed, and daily lag composite maps were built with respect to positive and negative peaks of the daily EUw values. An analysis of the probabilities of warm and cold weather event also indicates strong dependence on the EU phase.

Mangrove forests growing at the poleward edges of their geographic distribution are occasionally subject to freezing (<0 °C) and cold wave (>0 °C) events. Cold wave effects on mangrove trees are well documented and adaptation to cold stress has been reported for local mangrove populations in the North Atlantic. However, there is less understanding of effects of cold waves on mangroves in the northern Pacific, especially at the regional scale. Moreover, it is unclear if cold tolerant mangrove species of North Asia display variation in resistance to cold temperatures across their geographic distribution. Using a cold wave event that occurred in January 2021, we evaluated the effects of low temperatures on vegetation index (VI) change (relative to a recent five-year baseline) for mangrove forests dominated by Kandelia obovata (Rhizophoraceae) and Avicennia marina (Acanthaceaee) at the northern edge of their geographical range. We used two VIs derived from Sentinel-2 imagery as indicators for canopy health: the normalized difference infrared index (NDII) and the chlorophyll red-edge index (ChlRE), which reflect forest canopy water content and chlorophyll concentration, respectively. We isolated the cold wave effects on the forest canopy from phenology (i.e., cold wave induced deviation from a five-year baseline) and used multiple linear regression to identify significant climatic predictors for the response of mangrove forest canopy VI change to low temperatures. For areas where the cold wave resulted in temperatures <10 °C, immediate decreases in both VIs were observed, and the VI difference relative to the baseline was generally greater at 30-days after the cold wave than when temperatures initially recovered to baseline values, showing a slight delay in VI response to cold wave-induced canopy damage. Furthermore, the two VIs did not respond consistently suggesting that cold-temperature induced changes in mangrove canopy chlorophyll and water content are affected independently or subject to differing physiological controls. Our results confirm that local baseline (i.e., recent past) climate predicts canopy resistance to cold wave damage across K. obovata stands in the northern Pacific, and in congruence with findings from New World mangroves, they imply geographic variation in mangrove leaf physiological resistance to cold for Northern Pacific mangroves. [ABSTRACT FROM AUTHOR]

Reconstructing high-resolution glacial fluctuation is critical for understanding glaciers response to climate change. Here, we present a detailed Late Holocene glacial record from the Bhutanese Himalaya based on 27 10Be surface exposure ages. This record includes a glacial event 4180 ± 270 yr, followed by four glacial events at 2990 ± 190, 1780 ± 110, 1230 ± 80 and 500 ± 70 yr, respectively. These glacial events are synchronous with those in the Tibetan Plateau (TP) and its surrounding mountains, which likely reflect regional climatic forcing. The comparisons of regional climate data indicate that these Late Holocene glacial events occured in relatively cold and dry climatic conditions, reflecting the glacial fluctuations were more sensitive to temperature than to precipitation. In addition, the timing of these glacial events is roughly in agreement with the North Atlantic (NA) region's cooling events. It seems that the glacial fluctuations were teleconnected with the NA region's cooling events by the Westerlies, which acts as a cold-air conveyer between the NA and the TP during the cold intervals. Although the weakening of Indian summer monsoon would reduce the precipitation and glacier accumulation in the study area, the low temperature brought by the Westerlies greatly reduces the amount of glacial ablation, resulting in an increase in the net accumulation of glaciers. • We constrain five glacial events occurred during the Late Holocene. • The chronology is mostly synchronous with that of other areas of the Tibetan Plateau and its surrounding mountains. • Temperature is the major driving force of glacial events in the Bhutanese Himalaya. • The glacial chronology identify a full suite of Bond events during the Late Holocene. • The glacial events in the Tibetan Plateau were teleconnected with the North Atlantic region's cold events by the Westerlies. [ABSTRACT FROM AUTHOR]

Unseasonably cold weather episodes have the potential to cause dislocation to many aspects of society, regardless of the season in which they occur. In this work we devise a method for quantitatively identifying extreme cold events in such a way that it is not biased to the winter season (as is usual in most other studies). We have applied this method to the daily maximum temperatures (over the period January 1972 to June 1991) in the southern Australian cities of Melbourne andPerth. We identify 10 cold events in winter and summer for the cities. Analyses were performed to determine the synoptic environment in which these events occurred. The most common synoptic type in these samples was the `classic', which is characterised by, amongst other factors, the passage of a cold front over the city on the day of the outbreak, and the transport of air from subantarctic latitudes. Melbourne recorded five such events in summer and six in winter, while seven and eight occurred in the two seasons for Perth. The circulation features and characteristics of other synoptic types identified with these episodes is also examined. The mean synoptic anomalies which are coincident with these cold events are analysed. For both cities and seasons there is a `high-low' anomalous dipole in the regional MSLP pattern, with the high located in the `upstream' quadrant from the anomalous cyclone. Having said this, the relative importance of the two features of the dipole in being associated with the cold event strongly depended on the city and season under consideration. The research shows that the regional structures associated with cold events in Melbourne and Perth bear some similarity, but also display a number of significant differences. These differences are associated partly with thedifferent climatological and synoptic settings in which these citiesfind themselves, and the nature of their seasonality. [ABSTRACT FROM AUTHOR]