Strongest MJO on Record Triggers Extreme Atacama Rainfall and Warmth in Antarctica

Rondanelli, Roberto; Hatchett, Benjamin J.; Rutllant, José A.; Bozkurt, Deniz; Garreaud, René D.

doi:10.1029/2018gl081475

Cited by 54 publications

(24 citation statements)

References 39 publications

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“…We demonstrate the importance of Rossby wave breaking and intense moisture transport for EPEs using a selection of 12 notorious flood events that have been the subject of previous case studies (Table 2). Most of these events led to im- (Hong et al, 2011;Martius et al, 2013), the Atacama Desert floods in March 2015 (Wilcox et al, 2016;Bozkurt et al, 2016;Rondanelli et al, 2019), and the September 1987 Natal floods in South Africa (van Heerden and Taljaard, 1998). It should be noted here that the dates of the EPEs, as listed in Table 2, are as mentioned in the cited case studies, while the periods of the flood events and attributed socioeconomic impacts from the EM-DAT records can cover much longer periods.…”

Section: Example Cases Of Extreme Precipitation and Floodingmentioning

confidence: 90%

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A global climatological perspective on the importance of Rossby wave breaking and intense moisture transport for extreme precipitation events

Vries

Jan²

2021

Weather Clim. Dynam.

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Abstract. Extreme precipitation events (EPEs) frequently cause flooding with dramatic socioeconomic impacts in many parts of the world. Previous studies considered two synoptic-scale processes, Rossby wave breaking and intense moisture transport, typically in isolation, and their linkage to such EPEs in several regions. This study presents for the first time a global and systematic climatological analysis of these two synoptic-scale processes, in tandem and in isolation, for the occurrence of EPEs. To this end, we use 40-year ERA-Interim reanalysis data (1979–2018) and apply object-based identification methods for (i) daily EPEs, (ii) stratospheric potential vorticity (PV) streamers as indicators of Rossby wave breaking, and (iii) structures of high vertically integrated horizontal water vapour transport (IVT). First, the importance of these two synoptic-scale processes is demonstrated by case studies of previously documented flood events that inflicted catastrophic impacts in different parts of the world. Next, a climatological quantification shows that Rossby wave breaking is associated with >90 % of EPEs over central North America and the Mediterranean, whereas intense moisture transport is linked to >95 % of EPEs over many coastal zones, consistent with findings of atmospheric river-related studies. Combined Rossby wave breaking and intense moisture transport contributes up to 70 % of EPEs in several subtropical and extratropical regions, including (semi)arid desert regions where tropical–extratropical interactions are of key importance for (heavy) rainfall. Odds ratios of EPEs linked to the two synoptic-scale processes suggest that intense moisture transport has a stronger association with the occurrence of EPEs than Rossby wave breaking. Furthermore, the relationship between the PV and IVT characteristics and the precipitation volumes shows that the depth of the wave breaking and moisture transport intensity are intimately connected with the extreme precipitation severity. Finally, composites reveal that subtropical and extratropical EPEs, linked to Rossby wave breaking, go along with the formation of upper-level troughs and cyclogenetic processes near the surface downstream, reduced static stability beneath the upper-level forcing (only over water), and dynamical lifting ahead (over water and land). This study concludes with a concept that reconciles well-established meteorological principles with the importance of Rossby wave breaking and intense moisture transport for the formation of EPEs. Another conclusion with major implications is that different combinations of Rossby wave breaking and intense moisture transport can reflect a large range of EPE-related weather systems across climate zones and can thus form the basis for a new classification of EPE regimes. The findings of this study may contribute to an improved understanding of the atmospheric processes that lead to EPEs and may find application in climatic studies on extreme precipitation changes in a warming climate.

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Section: Example Cases Of Extreme Precipitation and Floodingmentioning

confidence: 90%

“…4.1). Odds ratios have also been used in previous studies to estimate the likelihood of precipitation extremes to occur in relation to several synoptic-scale weather systems (Röthlisberger et al, 2016;Lenggenhager and Martius, 2019;Moore et al, 2019).…”

Section: Matching Of Epes With Rossby Wave Breaking and Intense Moistmentioning

confidence: 99%

A global climatological perspective on the importance of Rossby wave breaking and intense moisture transport for extreme precipitation events

Vries

Jan²

2021

Weather Clim. Dynam.

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“…IVT is a useful metric to include because it shows promise in advancing forecast lead time (Lavers et al, 2016). We use potential vorticity on the 330 K surface from the higher resolution (compared to MERRA‐2) hourly 0.25° Global Forecast System final analysis (GFS; NOAA Environmental Modeling Center, 2003) to diagnose Rossby wave breaking (RWB), a common precursor to extreme midlatitude weather events (e.g., Hu et al, 2017; Rondanelli et al, 2019), via the overturning of potential vorticity surfaces (Abatzoglou & Magnusdottir, 2006). The GFS output spans 2015–present, therefore we could not use it to calculate return intervals.…”

Section: Observational Data and Model Products Usedmentioning

confidence: 99%

Observations of an Extreme Atmospheric River Storm With a Diverse Sensor Network

Hatchett

Cao

Dawson

et al. 2020

Earth and Space Science

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Observational networks enhance real‐time situational awareness for emergency and water resource management during extreme weather events. We present examples of how a diverse, multitiered observational network in California provided insights into hydrometeorological processes and impacts during a 3‐day atmospheric river storm centered on 14 February 2019. This network, which has been developed over the past two decades, aims to improve understanding and mitigation of effects from extreme storms influencing water resources and natural hazards. We combine atmospheric reanalysis output and additional observations to show how the network allows: (1) the validation of record cool season precipitable water observations over southern California; (2) the identification of phenomena that produce natural hazards and present difficulties for short‐term weather forecast models, such as extreme precipitation amounts and snow level variability; (3) the use of soil moisture data to improve hydrologic model forecast skill in northern California's Russian River basin; and (4) the combination of meteorological data with seismic observations to identify when a large avalanche occurred on Mount Shasta. This case study highlights the value of investments in diverse observational assets and the importance of continued support and synthesis of these networks to characterize climatological context and advance understanding of processes modulating extreme weather.

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“…Also, Hosking et al (2013) highlighted that the ASL is an important synoptic system modulating the West Antarctic climate variability. In another study, with the aid of reanalysis data, Rondanelli et al (2019) highlighted the role of tropical variability in connection with the highest temperature recorded on continental Antarctica and associated large melting events over the Antarctic Peninsula.…”

Section: Introductionmentioning

confidence: 99%

Recent Near-surface Temperature Trends in the Antarctic Peninsula from Observed, Reanalysis and Regional Climate Model Data

et al. 2020

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This study investigates the recent near-surface temperature trends over the Antarctic Peninsula. We make use of available surface observations, ECMWF's ERA5 and its predecessor ERA-Interim, as well as numerical simulations, allowing us to contrast different data sources. We use hindcast simulations performed with Polar-WRF over the Antarctic Peninsula on a nested domain configuration at 45 km (PWRF-45) and 15 km (PWRF-15) spatial resolutions for the period 1991−2015. In addition, we include hindcast simulations of KNMI-RACMO21P obtained from the CORDEX-Antarctica domain (~50 km) for further comparisons. Results show that there is a marked windward warming trend except during summer. This windward warming trend is particularly notable in the autumn season and likely to be associated with the recent deepening of the Amundsen/Bellingshausen Sea low and warm advection towards the Antarctic Peninsula. On the other hand, an overall summer cooling is characterized by the strengthening of the Weddell Sea low as well as an anticyclonic trend over the Amundsen Sea accompanied by northward winds. The persistent cooling trend observed at the Larsen Ice Shelf station is not captured by ERA-Interim, whereas hindcast simulations indicate that there is a clear pattern of windward warming and leeward cooling. Furthermore, larger temporal correlations and lower differences exhibited by PWRF-15 illustrate the existence of the added value in the higher spatial resolution simulation.

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Strongest MJO on Record Triggers Extreme Atacama Rainfall and Warmth in Antarctica

Cited by 54 publications

References 39 publications

A global climatological perspective on the importance of Rossby wave breaking and intense moisture transport for extreme precipitation events

A global climatological perspective on the importance of Rossby wave breaking and intense moisture transport for extreme precipitation events

Observations of an Extreme Atmospheric River Storm With a Diverse Sensor Network

Recent Near-surface Temperature Trends in the Antarctic Peninsula from Observed, Reanalysis and Regional Climate Model Data

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