Hindcasts and Real-time Nowcast/Forecasts of Currents in the Gulf of Mexico

Kantha, Lakshmi; Choi, Jei-Kook; Leben, R. R.; Cooper, Cortis; Vogel, Michael; Feeney, Jim

doi:10.4043/10751-ms

Cited by 18 publications

(10 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For additional details of the model and its skill, see Kantha (2005) and Kantha et al (2005). See also Choi et al (1995), Kantha et al (1999), Kantha and Clayson (2000) and Schaudt et al (2001).…”

Section: Appendixmentioning

confidence: 95%

Death of three Loop Current rings

Lipphardt¹,

Poje²,

Kirwan³

et al. 2008

J Mar Res

Self Cite

View full text Add to dashboard Cite

The life cycle of large anticyclonic rings in the Gulf of Mexico (GOM) is widely described by pinch off from the Loop Current, migration across the Gulf and eventual spin down along the western slope. Extensive observational and modeling efforts provide a relatively consistent picture of rings pinching off from the Loop Current and of complex interaction between anticyclones and cyclones driven by bathymetry along the western and northwestern shelf. The observational record for Loop Current rings (LCRs) during the intermediate period of westward translation is less clear. A number of studies recognize distinct anomalies in LCR characteristics in deep water as the rings enter the western Gulf near 92-94W. These include abrupt changes in the geometry of observed drifter trajectories and derived eddy parameter fits as well as changes in both ring translation speeds and the estimated rate of ring decay. Such observations are consistent with intense interaction and mass exchange between the rings and other coherent mesoscale features known to be present in the western Gulf. We test the hypothesis that interactions with the ambient mesoscale field can lead to rapid loss of coherence of some LCRs well before they reach the 'eddy graveyard' in the western Gulf. We use the data-assimilating, eddyresolving numerical GOM model described by Kantha et al. (2005) to assess the fates of readily identified LCRs Fourchon, Juggernaut, and Millenium during the period July 1998 to August 2001. Lagrangian metrics, including relative dispersion of small drifter clusters seeded in the ring cores, analysis of evolving blobs seeded in the ring cores, and finite-scale Lyapunov exponents, are used to track model ring evolution. These metrics clearly show that interactions with existing mesoscale cyclones and anticyclones caused Fourchon and Juggernaut to break up near 92W on advective time scales. In addition, Millenium also experienced an intense deformation, stirring, and mixing episode near 92W. Blob studies showed that the core fluid of Millenium was ultimately dispersed over much of the western basin. Our results show that some LCRs may break up through interactions with existing western Gulf cyclones and anticyclones prior to reaching the western slope.

show abstract

Section: Appendixmentioning

confidence: 95%

Death of three Loop Current rings

Lipphardt¹,

Poje²,

Kirwan³

et al. 2008

J Mar Res

Self Cite

View full text Add to dashboard Cite

show abstract

“…Routine real-time nowcast/forecasts of the oceanic state in the Gulf have been made by Colorado University (CU) researchers under funding from Marathon's Climatology and Simulation of Eddies (CASE) project since 1998. The effort is described by Kantha et al 10 . Briefly, the CU version of the Princeton Ocean Model is used for these nowcast/forecasts.…”

Section: Observations and Numerical Modelsmentioning

confidence: 99%

A Look at Currents in the Gulf of Mexico in 1999 - 2000

et al. 2001

Self Cite

View full text Add to dashboard Cite

Oceanographic conditions in the Gulf of Mexico have been extensively studied from the summer of 1999 through the fall of 2000. These studies included cradle to grave surveys of Juggernaut Eddy; surveys in the Caribbean by several consortia; oceanographic surveys in support of hurricane research in the Gulf; measurements of inflow/outflow through the Yucatan Strait; and regional nowcasts and hindcasts of circulation. Several interesting phenomena have been observed during this period, including energetic bottom currents in excess of 2 knots and bottom furrows on the continental slope; the intrusion of one of the strongest eddies in a decade into the north-central Gulf leases; and strong midwater-column currents in SE Ewing Bank (~140 cm/s). This paper describes the observational data available and summarizes ongoing efforts to understand the oceanographic conditions during this period. Eventually, it is hoped that these efforts will lead to a better estimation of offshore structure design currents; an understanding of the dynamical causes of the strong mid-water-column currents; determining whether there is a link between the strong bottom currents at the base of the Sigsbee Escarpment and the Loop Current; and assessing the skill of the regional forecast/nowcast/hindcast oceanographic models.

show abstract

“…We will examine the Gulf of Mexico model with 1/12 • horizontal resolution (Kantha et al, 1999;Kantha and Clayson, 2000), (iii) to find the fundamental statistics of model pediciton skill and parameterize an evolution law for the mean prediction error. That in general allow to detect when model Lagrangian predictability breaks down.…”

Section: Trajectories Of These Quasi-lagrangian Drifters Reflect Thementioning

confidence: 99%

“…This system (Kantha et al, 1999;Schaudt et al, 2001; see also Kantha and Clayson, 2000) is based on the University of Colorado version of the Princeton Ocean Model (POM) with 1/12 • horizontal resolution and 24 σ −levels. The water inflow through the Yukatan Channel has been prescribed, the outflow through the Strait of Florida evolved with the model physics.…”

Section: Model Circulationmentioning

confidence: 99%

Lagrangian predictability of high-resolution regional models: the special case of the Gulf of Mexico

Chu

Ivanov

Kantha

et al. 2004

Nonlin. Processes Geophys.

View full text Add to dashboard Cite

Abstract. The Lagrangian prediction skill (model ability to reproduce Lagrangian drifter trajectories) of the nowcast/forecast system developed for the Gulf of Mexico at the University of Colorado at Boulder is examined through comparison with real drifter observations. Model prediction error (MPE), singular values (SVs) and irreversible-skill time (IT) are used as quantitative measures of the examination. Divergent (poloidal) and nondivergent (toroidal) components of the circulation attractor at 50 m depth are analyzed and compared with the Lagrangian drifter buoy data using the empirical orthogonal function (EOF) decomposition and the measures, respectively. Irregular (probably, chaotic) dynamics of the circulation attractor reproduced by the nowcast/forecast system is analyzed through Lyapunov dimension, global entropies, toroidal and poloidal kinetic energies. The results allow assuming exponential growth of prediction error on the attractor. On the other hand, the q-th moment of MPE grows by the power law with exponent of 3q/4. The probability density function (PDF) of MPE has a symmetrical but nonGaussian shape for both the short and long prediction times and for spatial scales ranging from 20 km to 300 km. The phenomenological model of MPE based on a diffusion-like equation is developed. The PDF of IT is non-symmetric with a long tail stretched towards large ITs. The power decay of the tail was faster than 2 for long prediction times.

show abstract

Hindcasts and Real-time Nowcast/Forecasts of Currents in the Gulf of Mexico

Cited by 18 publications

References 0 publications

Death of three Loop Current rings

Death of three Loop Current rings

A Look at Currents in the Gulf of Mexico in 1999 - 2000

Lagrangian predictability of high-resolution regional models: the special case of the Gulf of Mexico

Contact Info

Product

Resources

About