Links between blocking circulation and precipitation extremes over Romania in summer

Rîmbu, Norel; Ștefan, Sabina; Busuioc, Aristita; Georgescu, Florinela

doi:10.1002/joc.4353

Cited by 25 publications

(12 citation statements)

References 34 publications

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“…Thus, when defining synoptic conditions of extreme precipitation events, it is important to consider the event period. Many extreme precipitation events are related to atmospheric circulation blocking patterns (Rimbu et al, 2016). For events of several days' duration, patterns must be analysed over the entire episode.…”

Section: Introductionmentioning

confidence: 99%

Temporal continuity of extreme precipitation events using sub‐daily precipitation: application to floods in the Ebro basin, northeastern Spain

Merino

Fernández‐González

García‐Ortega

et al. 2017

Intl Journal of Climatology

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Extreme precipitation events have been studied widely in various regions because of their implications for hazard assessment and risk management, particularly those of a hydrologic nature. Extreme precipitation events have been commonly defined using daily precipitation series owing to a lack of long‐term data at higher temporal resolution. However, because of their potentially dramatic consequences, intense sub‐daily precipitation is of great importance for risk assessment. Here, we define a new concept of extreme precipitation event based on temporal continuity of that event through run analysis using hourly precipitation. The aim of this definition is to record intense precipitation events over a very short period as well as very persistent rainfall events that produce heavy accumulated precipitation over several days. Both types of event can present considerable hydrologic hazards and are not considered in the definition of extreme precipitation event that is based on a daily time scale. We applied this method to the 29 greatest flood events in the Ebro River basin during 2000–2014 to determine whether our definition can be used to identify events producing hydrologic risks. In addition, we compared the synoptic patterns and trends of events defined using this method and those based on a daily time scale. The results show that the new definition allowed for identification of the 29 analysed flood events (as opposed to extreme events based on a daily time scale), among which eight events were not identified. Moreover, using the new definition facilitates establishment of synoptic patterns and more detailed study of trends by discriminating events according to their duration. The results reveal how the use of daily precipitation can hide trends of shorter events, because positive trends are more dominant in extreme precipitation events at sub‐daily scale.

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Section: Introductionmentioning

confidence: 99%

Temporal continuity of extreme precipitation events using sub‐daily precipitation: application to floods in the Ebro basin, northeastern Spain

Merino

Fernández‐González

García‐Ortega

et al. 2017

Intl Journal of Climatology

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“…A special interest is given to massive precipitation over relatively short periods of time on small surfaces generating floods (Lionello et al, 2016;Pfahl, 2014;Rîmbu et al, 2016) as important phenomena resulting from the convective activity (Simeonov et al, 2009;Goodman et al, 1986;Soula et al, 1998).…”

Section: Introductionmentioning

confidence: 99%

The Distribution of the Monthly 24-Hour Maximum Amount of Precipitation in Romania According to their Synoptic Causes

Dobri¹,

Sfîcă²,

Ichim³

et al. 2017

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ABSTRACT:In the present paper we have analysed the synoptic conditions generating the maximum amount of precipitation within 24 hours in Romania. This study is based on the analysis of daily weather maps from different archived sources and also on the processing of ROCADA data set concerning the daily amount of precipitation in Romania (1961Romania ( -2013. Some main weather types (WTs) -specific for the occurrence of high amount of precipitation in Romania -were established, and the daily recording of the maximum amount of precipitation for 24 hours at monthly level was assigned to one of the defined WTs. Out of the total of 312 days analysed from the synoptic point of view, a total of 133 days (42.6%) were characterized by high atmospheric instability. The larger part of them (100 days) were determined by cold air advections associated to long-wave troughs propagating from North Atlantic towards the centre of European continent, while the rest of 33 days were generated by cut-off lows identified in the middle and upper troposphere in South-East Europe. As well, 124 days (39.7%) were assigned to Mediterranean cyclones transiting the region of Romania and 55 days (17.7%) were associated with Atlantic cyclones activity. The climatology of each synoptic type is presented. Also, regional and seasonal disparities are described using proper interpolation methods.

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“…The correlation was noted when statistical significance is equal to or exceeded the 90, 95% confidence levels (t-test). The PCC was used in [14,24] for analysis of the linkage between blocks and summer precipitation. First of all, we analyzed the correlation between E-BF, UWS-BF, ESM-BF, RFEOS-BF, and total precipitation in the Selenga Basin (95% confidence level was used).…”

Section: Methodsmentioning

confidence: 99%

“…Climatological distribution of blocking frequency over Eurasia was demonstrated in [14][15][16][20][21][22]. The links between atmospheric blocking and precipitation are described in several works [23][24][25][26][27][28]. The results of numerous papers have revealed the blocks to be the cause of both low and high precipitation.…”

Section: Introductionmentioning

confidence: 99%

The Linkage of the Precipitation in the Selenga River Basin to Midsummer Atmospheric Blocking

et al. 2019

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The linkage between atmospheric blocking (blocking frequency, BF) and total monthly July precipitation in the Selenga River Basin, the main tributary of Lake Baikal, for the period 1979–2016 was investigated. Based on empirical orthogonal functions (EOF) analysis, two dominant modes of precipitation over the Selenga River Basin were extracted. The first EOF mode (EOF 1) is related to precipitation fluctuations mainly in the Mongolian part of Selenga; the second EOF mode (EOF 2)—in the Russian part of Selenga. Based on two different modes obtained, the total amount of precipitation individually for the Russian and Mongolian part of Selenga was calculated. Correlation analysis has demonstrated that precipitation over the Mongolian part of the Selenga Basin is positively correlated to blocking over Eastern Siberia/Mongolia (80–120° E, ESM-BF). Precipitation over the Russian part of the Selenga Basin is positively correlated to blocking over the Urals-Western Siberia (50–80° E, UWS-BF) and European blocking (0–50° E, E-BF). However, the linkage is not stable, and after the mid-1990s, the obtained positive correlation became insignificant. The analysis has shown that the dominance of E or ESM-blocking in July was the primary driver of the existence of two precipitation modes over the Selenga River Basin. During 1996–2016, the negative trend of time coefficients of EOF 1 and 2 for precipitation in Selenga had been observed, which was characterized by displacement of positive precipitation anomalies outside the basin. At the same time, there was a weakening of the linkage between precipitation in the Selenga Basin and blocking frequency. We have revealed two wave-like modes over Northern Eurasia and the subtropical part of Eurasia corresponding to E, ESM-blocks in 1979–1995 and 1996–2016. The change of the Northern and subtropical wave modes is one of the causes for the weakening of the linkage between atmospheric blocking and precipitation in the Selenga Basin and as a consequence decreased precipitation in the Russian and Mongolian part of Selenga during 1979–2016.

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Links between blocking circulation and precipitation extremes over Romania in summer

Cited by 25 publications

References 34 publications

Temporal continuity of extreme precipitation events using sub‐daily precipitation: application to floods in the Ebro basin, northeastern Spain

Temporal continuity of extreme precipitation events using sub‐daily precipitation: application to floods in the Ebro basin, northeastern Spain

The Distribution of the Monthly 24-Hour Maximum Amount of Precipitation in Romania According to their Synoptic Causes

The Linkage of the Precipitation in the Selenga River Basin to Midsummer Atmospheric Blocking

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