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The atmospheric large‐scale environment determines the occurrence of local extreme precipitation, and it is unclear how climate change affects this relationship. Here we investigate the present‐day relationship between large‐scale circulation types (CTs) and daily precipitation extremes over Scandinavia and its future change. A 50‐member EC‐Earth3 large ensemble is used to assess future changes against internal variability. We show that CTs are related to extreme precipitation over the entire domain. The intensity of extreme daily precipitation increases in all seasons in the future climate, generally following the strength of warming in the six different future scenarios considered. However, no significant future change is found in the relationship between extreme precipitation and the CTs in any season or scenario. The results have important implications for applications that rely on the stability of this relationship, such as statistical and event‐based dynamical downscaling of future weather and climate predictions and long‐term climate projections. Plain Language Summary The occurrence of local devastating extreme precipitation events is influenced by the large‐scale flow of the atmosphere, that is, high‐ or low‐pressure systems and winds from different directions. Understanding this connection helps us to predict precipitation extremes using more readily available information about the large‐scale flow. However, it is not known if the relationship that we observe in the present climate will hold under future climate conditions. Here we study the present‐day relationship between the large‐scale flow and local precipitation events over Scandinavia and analyze how it will change toward the end of the 21st century. We find that extreme precipitation events become more intense over entire Scandinavia in the future climate, but their connection to the large‐scale environment remains unchanged. Key Points Large‐scale circulation types (CTs) can be used as precursors of local extreme precipitation events over Scandinavia The intensity of extreme precipitation events over Scandinavia increases with the warming strength in the future climate The relationship between extreme precipitation and CTs remains unchanged over Scandinavia in the future climate

Being strongly influenced by internal climate variability, the atmospheric circulation response to greenhouse gas forcing in the future climate is uncertain. This study addresses atmospheric circulation through representative circulation types (CTs) and investigates the CTs’ changes with respect to frequency and effect on surface temperature and precipitation over a pan-Scandinavian domain. The analysis is based on the Swedish Meteorological and Hydrological Institute Large Ensemble performed with EC-Earth3: 50-member ensembles from one historical and six scenario simulations for the twenty-first century are used to assess internal variability and significance of changes. Although the results show no strong future changes in the CTs’ sea level pressure patterns, CT frequency changes suggest a future extension of summer conditions towards spring and autumn and point towards a clearer distinction between summer and winter. The present-climate CT effect on surface temperature is found to generally weaken which is consistent with a general decrease in temperature variability. Largest-scale and strongest temperature effect changes are projected between March and May for CT3, a cyclone towards the east of the domain associated with a domain-wide cooling effect that will likely be decreased towards the end of the twenty-first century. Similarly but of opposite sign, the CT effect on precipitation is strengthening as a result of the increased precipitation variability. Here, largest-scale and strongest effect enhancement is found for CT6, thus increasing its wetting effect over southern Scandinavia and drying effect west of the Scandes. Changes are generally largest towards the end of the twenty-first century and tend to increase with the forcing strength, thus maximizing for SSP585.

During strong El Niño events, below-average rainfall is expected in large parts of southern Africa. The 1992 El Niño season was associated with one of the worst drought episodes in large parts of South Africa. Using reanalysis data set from NCEP-NCAR, this study examined circulation types (CTs) in Africa south of the equator that are statistically related to the El Niño signal in the southwest Indian Ocean and the implication of this relationship during the 1992 drought episode in South Africa. A statistically significant correlation was found between the above-average Nino 3.4 index and a CT that features widespread cyclonic activity in the tropical southwest Indian Ocean, coupled with a weaker state of the south Indian Ocean high-pressure. During the analysis period, it was found that the El Niño signal enhanced the amplitude of the aforementioned CT. The impacts of the El Niño signal on CTs in southern Africa, which could have contributed to the 1992 severe drought episode in South Africa, were reflected in (i) robust decrease in the frequency of occurrence of the austral summer climatology pattern of atmospheric circulation that favors southeasterly moisture fluxes, advected by the South Indian Ocean high-pressure; (ii) modulation of easterly moisture fluxes, advected by the South Atlantic Ocean high-pressure, ridging south of South Africa; (iii) and enhancement of the amplitude of CTs that both enhances subsidence over South Africa, and associated with the dominance of westerlies across the Agulhas current. Under the ssp585 scenario, the analyzed climate models suggested that the impact of radiative heating on the CT significantly related to El Niño might result in an anomalous increase in surface pressure at the eastern parts of South Africa.

Thirty-year periods are treated in climatology as spans with relatively representative and stable climatic patterns, which can be used for calculating climate normals. Annual and seasonal series of circulation types were used to compare two 30-year sub-periods, 1961–1990 and 1991–2020, the second one being strongly influenced by recent global warming. This analysis was conducted according to the objective classification of circulation types and the climatic characteristics of sunshine duration, temperature, humidity, precipitation, and wind speed as calculated for the territory of the Czech Republic during the 1961–2020 period. For both sub-periods, their statistical characteristics were calculated, and the statistical significance of differences between them was evaluated. There was a statistically significant increase in the annual frequencies of anticyclonic circulation types and a significant decrease in cyclonic circulation types during 1991–2020 compared with 1961–1990. Generally, in both 30-year periods, significant differences in means, variability, characteristics of distribution, density functions, and linear trends appear for all climatic variables analysed except precipitation. This indicates that the recent 30-year “normal” period of 1991–2020, known to be influenced more by recent climate change, is by its climatic characteristics unrepresentative of the stable climatic patterns of previous 30-year periods.

This study addresses the applicability of general circulation models (GCMs) in studying the impact of climate change on hydrology. The statistical downscaling of precipitation based on circulation types (CTs) derived from the fuzzy, i.e., more than one CTs can occur in a given day, obliquely rotated principal component analysis is suggested as a robust methodology in using climate models to research the impact of climate change on hydrology. The methodology allows understanding of the mechanism of atmospheric circulation in the study region, and the physical relationship between atmospheric circulation and the regional hydrological cycle. The capability of climate simulations from the Max Planck Institute Earth System Model (MPI-ESM) GCM to reproduce the observed CTs in the target region is examined in light of the uncertainty of atmospheric GCMs when used for circulation typing. The results were discussed and it showed that, generally, the analyzed GCM can reproduce the underlying physics of atmospheric circulation in the study region, represented by the CTs, together with their dominant periods, probability of occurrence, and annual frequency of occurrence with modest biases. Generally, the Coupled Model Intercomparison Project 6 (CMIP6) simulation indicates some improvement for the CT-based analysis relative to the CMIP5 counterpart; however, this depends on the analyzed CT.

River floods in the mountainous regions of the Ukrainian Carpathians are a natural hazard that often leads to significant destruction and substantial economic damage to the region. The key driver of flooding is typically heavy rainfall, which results from certain patterns in regional atmospheric circulation. We studied the atmospheric circulation regimes over Ukraine for the period 1948–2021 using the modified Jenkinson–Collison classification. Circulation types associated with airflows from the western quarter are the most frequent throughout the year. However, seasonality in circulation patterns related to the dynamics of regional atmospheric centers of action is also well expressed. The linear trends in the frequency of circulation types are found statistically significant for meridional processes associated with advection from the north or south. Circulation types according to the Jenkinson–Collison classification, as well as the Niedźwiedź regional synoptic classification, were applied to cases of extreme floods in the river basins of the Ukrainian Carpathians to identify features of the pressure field leading to the formation of heavy precipitation. During the study period, 10 flood events, characterized by extremely high or historically significant water levels, were selected. Both pluvial floods in summer and mixed floods in winter were considered. In cases of the warm period, the circulation types with airflows directed towards the mountain range from the east or north are observed, and floods formed in the Ciscarpathia. In the cold period, circulation types with airflows from the western quarter increased precipitation and river discharge in Transcarpathia. 45% of observed circulation types belonged to the cyclonic group; however, the relative position of baric systems in other types also ensured the convergence of atmospheric moisture into the flood area. River floods in the Ukrainian Carpathians are a recurring natural disaster that causes significant destruction and economic damage. The circulation type can be an effective indicator in assessing flood risk, which is produced by operational meteorological services and plotted for public use.

Many studies in Europe have investigated the relationship between climatological variables and circulation patterns expressed by various classifications of circulation types. This study provides new insights based on an analysis of precipitation in the western (Bohemia—BOH) and eastern (Moravia and Silesia—M&S) parts of the Czech Republic with respect to the subjective classification of the Czech Hydrometeorological Institute and objective classification based on the flow strength, flow direction, and vorticity during the 1961–2020 period. Circulation types are investigated in regard to their contributions to the total precipitation, mean daily precipitation totals, and precipitation probability (daily totals ≥ 1.0 mm). Types with a westerly airflow and a trough over Central Europe exhibit the highest proportions in precipitation totals. Types with a cyclone over Central Europe, especially combined with a northwestern (BOH) or northeastern (M&S) airflow, result in the highest daily mean totals and precipitation probability. Types with a southwestern airflow transport more precipitation to BOH, while those with a northeastern airflow transport more precipitation to M&S, with a slight seasonal shift in the gradient axis between winter and summer. Circulation types under both classifications are examined from the perspective of their precipitation representation in BOH and M&S and the differences between these two regions. In addition, the suitability of both classifications for precipitation analysis is investigated.

The primary aim of this study is to examine the characteristics of atmospheric circulation patterns at various geopotential levels and their relationship with precipitation in southern Romania during the period from 1961 to 2020. Daily geopotential heights (1000 hPa, 850 hPa, 700 hPa and 500 hPa) were utilized in an automatic updated atmospheric circulation scheme for the creation of daily calendars of 12 circulation types (5 anticyclonic and 7 cyclonic) as well as daily time series derived from five stations over the domain of interest. To assess the influence of the atmospheric circulation on precipitation, correlations and time trends were explored between the rainfall totals and the different circulation types. The findings reveal a rising trend in anticyclonic circulation types across the region, while cyclonic types exhibit a consisted decrease. Precipitation and number of rain days percentages associated with specific cyclonic types depend on the geopotential levels, while annual and seasonal precipitation linked to cyclonic types decreases progressively from higher to lower levels. The strongest correlations in circulation type frequencies are observed between adjacent circulation types. Taylor diagram analysis indicates that the relationships between circulation types and precipitation vary both seasonally and across different atmospheric levels. Notably, the two rainiest circulation types are more accurately simulated at higher atmospheric levels (700 hPa and 500 hPa).

The temporal and spatial variations of 26 extreme temperature and precipitation indices for China and Greece were comparatively analysed. Also, their association with atmospheric circulation types was evaluated using multiple linear regression. The calculation of the extreme indices was based on homogenized daily temperature and precipitation time series from 1960 to 2010 for Greece and 2021 for China. Extreme precipitation, intensity, and short-term heavy precipitation increased, while persistent heavy precipitation has decreased since 1960 in China. Short-term heavy precipitation has also shown an increasing trend in Greece, though total precipitation and persistent heavy precipitation decreased there between 1960 and 2010. Extreme cold events have tended to decrease, and extreme warm events have increased in both countries, a fact that can be attributed to global warming. For comparison, climatic warming in China was mainly seen in the half year of winter, while the extreme indices relevant to cold seasons such as FD0 and ID0 presented a small trend in Greece. The observed changes in many climatic indices, including RX5day and WSDI in China and R20MM, RX5day, CDD, PRCPTOT and FD0 in Greece, could be partly explained by those of the main large-scale circulation types in the corresponding regions. The significant multiple correlation coefficients of the main circulation types were up to 0.53 for RX5day and 0.54 for WSDI in China, and 0.74 for PRCPTOT and 0.71 for R20MM in Greece. The relationships between climatic indices and circulation types were closer in Greece than in China, especially for the precipitation indices.

The atmospheric circulation, not only near the surface but also at high altitudes, is probably the main factor determining the weather and climate of a given area, along with its latitude, altitude, the shape of the relief of the area and its surroundings, and the proximity of water basins of different sizes. The main objective of this study is to investigate the relationship between anticyclonic circulation types in the middle troposphere at the 500 hPa level and the seasonal summer temperature over the region of the central Balkan Peninsula, particularly Bulgaria. A previously compiled classification of atmospheric circulation is used, and the frequencies of the circulation types are correlated with the mean seasonal (monthly) temperature, where the extreme seasons and months are defined as the 10th percentile for cold summer seasons and months and the 90th percentile for warm ones. A positive and statistically significant correlation was found for the anticyclones located southwest of Bulgaria and a negative one for those located southeast of it. A comparison between the last two 30-year climatological periods (1961–1990 and 1991–2020) was also made, and an irrefutable decrease in the number of cold summer seasons from 257 to just 17 was found in the last 30 years, respectively, as well as a rapid increase in the number of extreme warm summer seasons from 26 to 263, encompassing all 15 meteorological stations studied.