Cyclone Tracking in Different Spatial and Temporal Resolutions

Blender, Richard; Schubert, Michael

doi:10.1175/1520-0493(2000)128<0377:ctidsa>2.0.co;2

Cited by 124 publications

(150 citation statements)

References 9 publications

Supporting

Mentioning

129

Contrasting

Unclassified

Order By: Relevance

“…In exceptional cases, it was found that up to three adjacent gridpoints recorded the same geopotential minimum value at a given time-level. For such cases, the stencil was enlarged and the algebraic average of the longitudinal and latitudinal coordinates of the gridpoints sharing the geopotential minimum value was taken as the position of the closed low at timelevel t (Lambert, 1988;Blender and Schubert, 2000). (B) The tracking of closed lows in time is carried out in an iterative procedure where all the height minima identified at time-level t are subjected to the tracking criteria that entail the following: (a) For each height minimum identified at time-level t, all height minima at time-level t + 1, which are located within a radius of 700 km from a timelevel t height minimum, are considered for the track associated with the time-level t height minimum.…”

Section: Methodsmentioning

confidence: 99%

Tropical systems from the southwest Indian Ocean making landfall over the Limpopo River Basin, southern Africa: a historical perspective

Malherbe

Engelbrecht

Landman

et al. 2011

Intl Journal of Climatology

View full text Add to dashboard Cite

ABSTRACT:The study provides perspective on the contribution of landfalling tropical systems (cyclones, depressions, storms and lows) from the southwest Indian Ocean (SWIO) towards rainfall over the eastern interior of southern Africa, over the period . Although these systems contribute to <10% of the annual rainfall occurring over the region, their relative contribution to local and widespread heavy rainfall events is shown to be highly significant. About 50% of widespread heavy rainfall events over northeastern South Africa are caused by landfalling tropical systems. Fourier analysis performed on the time series of rainfall occurring over northeastern South Africa in association with these systems reveals the existence of a quasi-18-year cycle. The cycle coincides with the well-known quasi-18-year Dyer-Tyson cycle in rainfall over the summer rainfall region of South Africa. These results suggest that atmospheric and surface conditions leading to wet phases of the Dyer-Tyson cycle also favour the landfall and subsequent westward movement of tropical systems from the SWIO over southern Africa -and their eventual contribution to rainfall over northeastern South Africa and southern Zimbabwe.

show abstract

Section: Methodsmentioning

confidence: 99%

Tropical systems from the southwest Indian Ocean making landfall over the Limpopo River Basin, southern Africa: a historical perspective

Malherbe

Engelbrecht

Landman

et al. 2011

Intl Journal of Climatology

View full text Add to dashboard Cite

show abstract

“…Blender and Schubert, 2000;Sickmoller et al, 2000;Geng and Sugi, 2001;Hanson et al, 2004). This can work satisfactorily for a small number of large, wellspaced features, but would be an unequivocal failure if used here, due to the wide range and large number of features identified, some of which move very rapidly (e.g.…”

Section: Comparison With Previous Studiesmentioning

confidence: 90%

“…These amount to even larger shortfalls compared to the synoptic charts. Whilst analysis period inconsistencies will have had an impact, the primary causes of the shortfalls are likely to be lower spatial resolution of input data (see Blender and Schubert, 2000), simpler identification methodologies, and different thresholding methods. In particular this comparison reiterates the limitations of using surface pressure minima (or equivalently 1000 hPa heights) in isolation, even at higher resolution, as Hoskins and Hodges and others have recognized.…”

Section: Synoptic Validitymentioning

confidence: 99%

“…Though not so critical in the former case, in the latter case the timeliness aspect is extremely important. Previously, Blender and Schubert (2000), have highlighted the big advantages of using a small time interval, such as 4 h; it is, however, noteworthy that they used only the nearest neighbour approach, which, as they recognize, influences their conclusions. 'Half-time tracking', with 'steering wind' estimates, now looks to be a viable alternative, and has indeed helped us to successfully use a 12 h time interval.…”

Section: Half-time Tracking and Time Intervalsmentioning

confidence: 99%

See 1 more Smart Citation

Objective identification, typing and tracking of the complete life-cycles of cyclonic features at high spatial resolution

Hewson

Titley

2010

Met. Apps

View full text Add to dashboard Cite

Synoptic-scale cyclonic features provide an inescapable focal point for operational forecasting, whilst the merits of tracking such features are increasingly being recognized in the climate change field. Close association with adverse and extreme weather is the main motivator. Here a new and highly sophisticated set of techniques to detect, classify and track the full range is developed. A revised conceptual model of cyclone development provided the initial framework, ensuring a solid bond with forecasting practice, whilst also connecting closely to baroclinic life-cycle concepts. Building on this, cyclones are detected using a hybrid of geopotential minimum/vorticity maximum techniques, whilst incorporating important extensions to ensure that vorticity can be used at high resolution (∼50 km) and that features on fronts take priority. To track the features across time, at intervals of 12 h or less, feature attributes in the association process are used. Additionally, an upper-tropospheric steering wind is employed to estimate future and past positions. This facilitates 'half-time tracking', a new approach that has clear-cut advantages over 'full-time tracking' employed elsewhere.In detection tests, comparing with subjectively-drawn charts, the feature hit rate was 84%, and the false alarm ratio 17%, whilst in a simple tracking test the association failure rate was just 2%. These values compare very favourably with previous studies.One key application is discussed. This involves processing ensemble output to provide wide-ranging real-time products tailor-made to forecasters' needs. Products include track-following plume diagrams, for various cyclone attributes, and storm-track strike probability plots for different thresholds of severity.

show abstract

“…In exemplary form, three strategies will be briefly described. The approach of Blender and Schubert (2008) identifies minima of the 1000 hPa geopotential field (z1000) within a neighbourhood of 8 grid points of a reference point. In order to be able to include very weakly developed centers, a minimum gradient (20 gpm per 1000 km) in a given area (radius 1000 km) is required.…”

Section: -Regional Climate Projections (Christensen Et Al 2007)mentioning

confidence: 99%

A robust method to identify cyclone tracks from gridded data

2010

View full text Add to dashboard Cite

Abstract.A system to derive tracks of barometric minima is presented. It is deliberately using coarse input data in space (order of 2• × 2 • ) and time (6-hourly to daily) as well as information from just one geopotential level. It is argued that the results are, for one robust in the sense of an assumption of the IMILAST Project that the use of as simple as possible metrics should be strived for and for two tailored to the input from reanalyses and GCMs. The methodology presented is a necessary first step towards an automated storm track recognition scheme which will be employed in a second paper to study the future development of atmospheric dynamics in a changing climate. The process towards obtaining storm tracks is two-fold. In its first step cyclone centers are being identified. The performance of this step requires the existence of closed isolines, i.e., a topology in which a grid-point is surrounded by neighbours which all exhibit higher geopotential. The usage of this topology requirement as well as the constraint of coarse data may lead, though, to limitations in identifying centers in geopotential fields with shallow gradients that may occur in the summer months; moreover, some centers may potentially be missed in case of a configuration in which a small scale storm is located at the perimeter of a deep and very large low (a kind of "dent in a crater wall"). The second step of the process strings the identified cyclone centers together in a meaningful way to form tracks. By way of several examples the capability to identify known storm tracks is shown.

show abstract

Cyclone Tracking in Different Spatial and Temporal Resolutions

Cited by 124 publications

References 9 publications

Tropical systems from the southwest Indian Ocean making landfall over the Limpopo River Basin, southern Africa: a historical perspective

Tropical systems from the southwest Indian Ocean making landfall over the Limpopo River Basin, southern Africa: a historical perspective

Objective identification, typing and tracking of the complete life-cycles of cyclonic features at high spatial resolution

A robust method to identify cyclone tracks from gridded data

Contact Info

Product

Resources

About