From the concept of “Kaltlufttropfen” (cold air pool) to the cut-off low. The case of September 1971 in Spain as an example of their role in heavy rainfalls

Llasat, M. C.; Martín, Francisco; Barrera, Antonio

doi:10.1007/s00703-006-0220-9

Cited by 35 publications

(33 citation statements)

References 15 publications

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“…In the case of the river basins, the spatial precipitation variability assumes even more importance. For example, most of the Top #25 events in the Ebro basin (not shown) correspond to days with precipitation falling only in the N/NE and E quadrants of the IP (Llasat et al , ). On the contrary, for the Tagus and Douro basins, these Top #25 events are generally characterized by widespread precipitation in the western and central IP.…”

Section: Resultsmentioning

confidence: 99%

A ranking of high‐resolution daily precipitation extreme events for the Iberian Peninsula

Ramos

Trigo

Liberato

2014

Atmospheric Science Letters

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A method for ranking daily precipitation events is presented based on the most comprehensive database of daily gridded precipitation dataset available for the Iberian Peninsula spanning from 1950 to 2008. The magnitude of an event is obtained after considering the area affected as well as its intensity in every grid point and taking into account the daily normalized departure from climatology. Different precipitation rankings are presented considering the entire Iberian Peninsula, Portugal and also the six largest river basins in the Iberian Peninsula.

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Section: Resultsmentioning

confidence: 99%

A ranking of high‐resolution daily precipitation extreme events for the Iberian Peninsula

Ramos

Trigo

Liberato

2014

Atmospheric Science Letters

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“…(2016) associated an early autumn 500-hPa cut-off low with a flooding event in Chile's Atacama region (around 268S in western South America) that left 31 dead, 16 people missing, and 16 588 people affected (ONEMI 2015). In Europe, Llasat et al (2007) found that 7 of the 22 most ''catastrophic'' floods in Mediterranean Spain between 1950 and 2000 were associated with cut-off lows. Thus, the study of cut-off lows is key to reducing their negative impacts.…”

Section: Introductionmentioning

confidence: 99%

A Midlatitude Climatology and Interannual Variability of 200- and 500-hPa Cut-Off Lows

2020

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A climatology of midlatitude 200- and 500-hPa cut-off low systems in the Northern and Southern Hemispheres is constructed from the NCEP–NCAR reanalysis by detecting and tracking, under one consistent method, all of the systems that persisted for more than 36 h for the 58 years of 1960–2017. This method identifies a cut-off low as a cold-core geopotential height minimum that is isolated from the main westerlies and with a strong temperature gradient on its eastern flank. The obtained spatial and seasonal distributions show preferred regions of occurrence and that within these regions there is a level-dependent seasonality of cut-off lows. Whereas 200-hPa systems are more frequent in summer and autumn, 500-hPa systems are more evenly distributed throughout the seasons. Within each region and at each level, the annual number of cut-off lows has been increasing over time, trends that are consistent with documented signals of climate change such as a weakening and poleward shift of the subtropical jets and an increase in blocking frequency. These trends explain as much as 64% of the variance in the annual number of cut-off lows. The contribution of the annular modes and El Niño–Southern Oscillation to the interannual variability of the number of cut-off lows per season in each hemisphere is also investigated. Only the Northern Hemisphere annular mode has a statistically significant negative correlation throughout all seasons that explains 18%–45% of the variance in the yearly number of Northern Hemisphere 500-hPa cut-off lows.

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“…Upper level PV anomalies are often associated with cutoff lows [ Llasat et al , 2007; Garreaud and Fuenzalida , 2007; Nieto et al , 2005]. Over Europe, Nieto et al [2005] found that about 73% of the cutoff lows were associated to a PV maximum and 47% developed surface lows.…”

Section: Introductionmentioning

confidence: 99%

An event of stratospheric air intrusion and its associated secondary surface cyclogenesis over the South Atlantic Ocean

Iwabe¹,

Rocha²

2009

J. Geophys. Res.

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[1] This work presents an analysis of a lowermost stratospheric air intrusion event over the coast of Brazil, which may have been responsible for a secondary surface cyclogenesis over the southwestern Atlantic Ocean. The surface cyclone initiated at 0600 UTC 17 April 1999 in a cold air mass in the rear of a cold front after a primary cyclone developed over the same region. The analysis of the secondary cyclone revealed the presence of lowermost stratospheric air intrusion characterized by anomalous potential vorticity (PV), dry air, and high concentration of ozone in atmospheric column. The system developed on the eastern side of an upper level core of PV anomaly, which induced a cyclonic wind circulation at lower levels and favored the onset of the secondary cyclone. In midlevels (500 hPa), the cutoff low development contributed to reduce the propagation speed of the wave pattern. This feature seemed to (1) allow the low-level cold/dry air to heat/moisten associated with sensible and latent fluxes transferred from the ocean to the atmosphere, which intensified a baroclinic zone parallel to the coast, and (2) contribute to the long duration of the system. The present analysis indicates that this secondary cyclone development could be the result of the coupling between the PV anomaly in the upper levels and low-level air-sea interaction.Citation: Iwabe, C. M. N., and R. P. da Rocha (2009), An event of stratospheric air intrusion and its associated secondary surface cyclogenesis over the South Atlantic Ocean,

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From the concept of “Kaltlufttropfen” (cold air pool) to the cut-off low. The case of September 1971 in Spain as an example of their role in heavy rainfalls

Cited by 35 publications

References 15 publications

A ranking of high‐resolution daily precipitation extreme events for the Iberian Peninsula

A ranking of high‐resolution daily precipitation extreme events for the Iberian Peninsula

A Midlatitude Climatology and Interannual Variability of 200- and 500-hPa Cut-Off Lows

An event of stratospheric air intrusion and its associated secondary surface cyclogenesis over the South Atlantic Ocean

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