A spatio-temporal Kalman filter for estimation of barotropic Rossby waves from altimeter data

Author(s):  
V. Solo
Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2841
Author(s):  
Khizer Mehmood ◽  
Abdul Jalil ◽  
Ahmad Ali ◽  
Baber Khan ◽  
Maria Murad ◽  
...  

Despite eminent progress in recent years, various challenges associated with object tracking algorithms such as scale variations, partial or full occlusions, background clutters, illumination variations are still required to be resolved with improved estimation for real-time applications. This paper proposes a robust and fast algorithm for object tracking based on spatio-temporal context (STC). A pyramid representation-based scale correlation filter is incorporated to overcome the STC’s inability on the rapid change of scale of target. It learns appearance induced by variations in the target scale sampled at a different set of scales. During occlusion, most correlation filter trackers start drifting due to the wrong update of samples. To prevent the target model from drift, an occlusion detection and handling mechanism are incorporated. Occlusion is detected from the peak correlation score of the response map. It continuously predicts target location during occlusion and passes it to the STC tracking model. After the successful detection of occlusion, an extended Kalman filter is used for occlusion handling. This decreases the chance of tracking failure as the Kalman filter continuously updates itself and the tracking model. Further improvement to the model is provided by fusion with average peak to correlation energy (APCE) criteria, which automatically update the target model to deal with environmental changes. Extensive calculations on the benchmark datasets indicate the efficacy of the proposed tracking method with state of the art in terms of performance analysis.


1996 ◽  
Vol 3 (2) ◽  
pp. 115-126 ◽  
Author(s):  
R. E. Glazman ◽  
A. Fabrikant ◽  
A. M. Greysukh

Abstract. Using a recently proposed technique for statistical analysis of non-gridded satellite altimeter data, regime of long equatorially-trapped baroclinic Rossby waves is studied. One-dimensional spatial and spatiotemporal autocorrelation functions of sea surface height (SSH) variations yield a broad spectrum of baroclinic Rossby waves and permit determination of their propagation speed. The 1-d wavenumber spectrum of zonal variations is given by a power-law k-2 on scales from about 103 km to 104 km. We demonstrate that the observed wave regime exhibits features of soliton turbulence developing in the long baroclinic Rossby waves. However, being limited to second statistical moments, the present analysis does not allow us to rule out a possibility of weak wave turbulence.


1997 ◽  
Vol 15 (11) ◽  
pp. 1478-1488 ◽  
Author(s):  
G. Chen ◽  
R. Ezraty

Abstract. It is becoming well known that aliasing associated with ocean tides could be a major source of systematic error in altimeter sea-level measurements, due to asynoptic sampling and imperfect tide modelling. However, it has been shown that signals of non-tidal origin may also contribute significantly to the observed aliasing. In this paper, numerical simulations are performed to demonstrate the full aliasing potential associated with altimeter observations of seasonal sea-level variability and annual Rossby waves. Our results indicate that ignorance of non-tidal aliasing may lead to the possibility of underestimating the total aliasing and misinterpreting or overlooking existing geophysical phenomena. Therefore, it is argued that an entire aliasing picture should be kept in mind when satellite altimeter data are analysed.


2005 ◽  
Vol 35 (2) ◽  
pp. 218-231 ◽  
Author(s):  
Stefano Pierini

Abstract A two-layer primitive equation box model of the North Pacific Ocean is used to highlight and analyze some general aspects of the linear large-scale boundary-driven oceanic variability that are detectable through altimeter observations. The model is forced by a white-noise wind, and a spectral analysis of the zonal and meridional, barotropic and baroclinic velocity components is carried out. Several dynamical features are identified in terms of boundary-driven Rossby waves, and their spatial structure and frequency dependence are examined theoretically and discussed in connection with recent studies based on altimeter data. In particular, the following aspects of the variability are analyzed: 1) beta-refracted baroclinic Rossby waves, which are found to be generated along the eastern boundary of the ocean by the passage of coastal Kelvin waves originating from the equatorial waveguide, and 2) westward-intensified barotropic Rossby waves, which originate from the western boundary of the ocean after reflection of longer waves generated in midocean. In the discussion the stress is put on dynamical aspects not yet fully understood and on the possibility that altimetry can provide further insight into their functioning.


2018 ◽  
Vol 2018 ◽  
pp. 1-13
Author(s):  
Muzi Li ◽  
Bo Xu ◽  
Jun Sun

A new orbit determination scheme targeting communication and remote sensing satellites in a hybrid constellation is investigated in this paper. We first design one such hybrid constellation with a two-layer configuration (LEO/MEO) by optimizing coverage and revisit cycle. The main idea of the scheme is to use a combination of imagery, altimeter data, and inter-satellite range data as measurements and determine orbits of the satellites in the hybrid constellation with the help of the extended Kalman filter (EKF). The performance of the new scheme is analyzed with Monte Carlo simulations. We first focus on an individual remote sensing satellite and compared the performance of orbit determination using only imagery with its counterpart using both imagery and altimeter measurements. Results show that the performance improves when imagery is used with altimeter data pointing to geometer calibration sites but declines when used with ocean altimeter data. We then expand the investigation to the whole constellation. When inter-satellite range data is added, orbits of all the satellites in the hybrid constellation can be autonomously determined. We find that the combination of inter-satellite range data with remote sensing observations lead to a further improvement in orbit determination precision for LEO satellites. Our results also show that the performance of the scheme would be affected when remote sensing observations on certain satellites are absent.


Sign in / Sign up

Export Citation Format

Share Document