The Climatology and Characteristics of Rossby Wave Packets Using a Feature-Based Tracking Technique

Souders, Matthew B.; Colle, Brian A.; Chang, Edmund K. M.

doi:10.1175/mwr-d-13-00371.1

Cited by 38 publications

(62 citation statements)

References 58 publications

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“…The reason that I is positive is that the extratropical cyclogenesis and associated convection lies on the poleward side of the jet (Figures (d) and (e), (c) and (d)). The locations of the composite cyclogenesis found here is consistent with Souders et al () (their Figure 3(a)), who showed that on average the annual number of significant Rossby wave packet formation points is generally largest in a midlatitude band across the Atlantic and Indian Oceans, with an isolated maximum west of South America.…”

Section: Discussionmentioning

confidence: 99%

“…Chang, 2005; Wirth and Eichhorn, 2014), storm track variability (e.g. Trenberth, 1991; Hakim, 2003; Souders et al , , ), organised convection (e.g. Kiladis and Weickmann, 1992a, 1992b; Kiladis, 1998; Matthews and Kiladis, 2000; Davidson et al , ; Martius et al , ; Lin and Li, 2012; Matthews, 2012; Fukutomi and Yasunari, 2014; van der Wiel et al , , ; Berry and Reeder, 2016), teleconnections and climates modes (e.g.…”

Section: Introductionmentioning

confidence: 99%

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Southern Hemisphere summertime Rossby waves and weather in the Australian region

O’Brien

Reeder

2017

Quart J Royal Meteoro Soc

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Motivated by recent studies on the significant summertime weather patterns in the Australian region, the life cycle of summertime transient Rossby wave packets in the Southern Hemisphere is investigated. The strength of the interaction I between the wave packets and the jet is defined by the advection of potential vorticity by the divergent part of the wind on the 350 K isentropic surface. The magnitude of I is used as the basis for time‐lagged composites in distinct regions: southwest Chile, southwest Africa, over the Indian Ocean, southwest Australia, and over the West Pacific. The interaction is strongest on the stratospheric side of the jet core. Although in each case cyclogenesis from a pre‐existing disturbance in the upper troposphere precedes the generation of the Rossby wave packets, there are two types of interaction with the jet. In the souhwest Chile, southwest Africa and Indian Ocean cases, extratropical cyclogenesis and the associated convection lies on the poleward side of the jet, and hence I is positive. In the southwest Australia and West Pacific cases, extratropical cyclogenesis occurs 3 days earlier than the others, and I is negative as it describes the interaction of a downstream propagating Rossby wave packet with the subtropical jet. In all cases, as the cyclones develop, the wave activity propagates from low levels to the upper levels of the troposphere, and then downstream and equatorwards towards higher values of refractive index. The equatorward refraction of the southwest Australia and West Pacific wave packets is accompanied by enhanced tropical convection in the warm conveyor belt of the advancing front.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Southern Hemisphere summertime Rossby waves and weather in the Australian region

O’Brien

Reeder

2017

Quart J Royal Meteoro Soc

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“…While it is entirely possible that changes to the tracking methodology, such as the use of multiple time steps in defining the speed of an object's motion, may yield better track fidelity, the results of this verification suggest that the quality of the tracking methods outlined in this paper is sufficient for studying the climatology of RWPs. A subsequent paper (Souders et al 2014) will use the second hybrid tracking approach to determine the global climatology of wave packets, and this tracking will also assist in studies of model validation and the determination of how RWPs change in future climate model scenarios.…”

Section: Discussionmentioning

confidence: 99%

A Description and Evaluation of an Automated Approach for Feature-Based Tracking of Rossby Wave Packets

Souders

Colle

Chang

2014

Monthly Weather Review

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This paper describes an automated approach to track Rossby wave packets (RWPs), and the sensitivity of various tracking parameters and methods used in filtering the raw data in the feature-based tracking. The NCEP-NCAR reanalysis meridional wind and geopotential height data at 300 hPa every 6 h were spectrally filtered using a Hilbert transform technique under the assumption that RWPs propagate along a waveguide defined by the 14-day running average of the 300-hPa wind. After some spatial and temporal smoothing, the local maxima in RWP amplitude (WPA) were tracked using two objective techniques: a point-based cost optimization routine and a hybrid approach using point identification and object-based tracking following rules. A variation of the total energy flux term of the eddy kinetic energy equation was used to subjectively verify RWP tracks in order to compare the performance of each tracking method. When tracking methods are verified over two winter seasons, the hybrid technique outperformed point-based tracking, particularly for track duration and propagation. Problems with tracking were found to be most common during periods when two RWPs merge, one RWP splits into multiple packets, or an RWP moves from one storm track to another. RWPs are found to move irregularly rather than linearly, with their motion and intensity best described as pulse like. The sensitivity to some of the parameters used in the tracking was also explored.

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“…7 in Archambault et al 2013), and that the frequency of RWT events over the North Pacific is lowest during the June-August period (see Fig. 4 in Souders et al 2014).…”

Section: Discussionmentioning

confidence: 92%

Multiscale Upstream and In Situ Precursors to the Elevated Mixed Layer and High-Impact Weather over the Midwest United States

Cordeira

Metz

Howarth

et al. 2017

Weather and Forecasting

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Two severe MCSs over the upper Midwest United States resulted in .100 mm of rain in a ;24-h period and .200 severe weather reports, respectively, during 30 June-2 July 2011. This period also featured 100 (104) daily maximum high (low) temperature records across the same region. These high-impact weather events occurred in the presence of an elevated mixed layer (EML) that influenced the development of the severe MCSs and the numerous record high temperatures. The antecedent large-scale flow evolution was influenced by early season Tropical Cyclone Meari over the western North Pacific. The recurvature and subsequent interaction of Meari with the extratropical large-scale flow occurred in conjunction with Rossby wave train amplification over the North Pacific and dispersion across North America during 22 June-2 July 2011. The Rossby wave train dispersion contributed to trough (ridge) development over western (central) North America and the development of an EML and the two MCSs over the upper Midwest United States. A composite analysis of 99 warm-season days with an EML at Minneapolis, Minnesota, suggests that Rossby wave train amplification and dispersion across the North Pacific may frequently occur in the 7 days leading up to EMLs across the upper Midwest. The composite analysis also demonstrates an increased frequency of severe weather and elevated temperatures relative to climatology on days with an EML. These results suggest that EMLs over the upper Midwest may often be preceded by Rossby wave train amplification over the North Pacific and be followed by a period of severe weather and elevated temperatures.

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The Climatology and Characteristics of Rossby Wave Packets Using a Feature-Based Tracking Technique

Cited by 38 publications

References 58 publications

Southern Hemisphere summertime Rossby waves and weather in the Australian region

Southern Hemisphere summertime Rossby waves and weather in the Australian region

A Description and Evaluation of an Automated Approach for Feature-Based Tracking of Rossby Wave Packets

Multiscale Upstream and In Situ Precursors to the Elevated Mixed Layer and High-Impact Weather over the Midwest United States

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