Forward electromagnetic scattering models for sea ice

Golden, Kenneth M.; Cheney, Margaret; Ding, Kung‐Hau; Fung, A.K.; Grenfell, Thomas C.; Isaacson, David; Kong, Jin Au; Nghiem, S. V.; Sylvester, John; Winebrenner, P.

doi:10.1109/36.718637

Cited by 48 publications

(54 citation statements)

References 92 publications

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“…The proliferation and growth of sea ice organisms is favored by permeable ice, which allows nutrient replenishment (10,11). For remote sensing, surface flooding and subsequent freezing can affect microwave backscatter from sea ice (12,13), and connectedness of the brine inclusions affects the permittivity of sea ice (14,15). As yet another example, it was observed in the Arctic that there was about a 20-day time lag between the start of the spring snow melt and the occurrence of freshwater input into the mixed layer (16,17).…”

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confidence: 99%

“…3), including fish, turtles, and champsosaurs. At least two types of fish are represented by scales similar to those described as Holostean A and Holostean B from Upper Cretaceous nonmarine sediments (15). Turtles and champsosaurs offer several advantages over other fossils used as climatic indicators, such as the latest Cretaceous dinosaurs of the North Slope, Alaska, because they are free from ambiguities posed by possible migration and warm-bloodedness (16,17).…”

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The Percolation Phase Transition in Sea Ice

Golden

Ackley

Lytle

1998

Science

448

397

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Sea ice exhibits a marked transition in its fluid transport properties at a critical brine volume fraction p c of about 5 percent, or temperature T c of about -5°C for salinity of 5 parts per thousand. For temperatures warmer than T c , brine carrying heat and nutrients can move through the ice, whereas for colder temperatures the ice is impermeable. This transition plays a key role in the geophysics, biology, and remote sensing of sea ice. Percolation theory can be used to understand this critical behavior of transport in sea ice. The similarity of sea ice microstructure to compressed powders is used to theoretically predict p c of about 5 percent.Sea ice is a complex, composite material consisting of pure ice with brine and air inclusions, whose size and geometry depend on the ice crystal structure, as well as the temperature and bulk salinity. It is distinguished from many other porous composites, such as sandstones or bone, in that its microstructure and bulk material properties vary dramatically over a small temperature range. For brine volume fractions p below a critical value p c Ϸ 5%, columnar sea ice is effectively impermeable to fluid transport, whereas for p above p c (Ͼ5%), brine or sea water can move through the ice. The relation of brine volume to temperature T and salinity S (1) implies p c corresponds to a critical temperature T c Ϸ -5°C for S ϭ 5 ppt; we refer to this critical behavior as the "law of fives." Perhaps the most direct observations of this are that the time rate of change of sea ice salinity dS/dt due to gravity drainage vanishes for brine volumes below 5% (2, 3) and that the permeability of thin sea ice decreases by more than two orders of magnitude as the surface temperature is lowered, in a small critical region around -5°C (4).Brine transport is fundamental to such processes as sea ice production through freezing of flooded ice surfaces, sea ice heat fluxes, and nutrient replenishment for sea ice algal communities, as well as being an important factor for remote sensing. However, the basic transition controlling brine transport has received little attention. Percolation theory (5, 6) has been developed to analyze the properties of materials where connectedness of a given component determines the bulk behavior. We show that it provides a natural framework to understand the critical behavior of sea ice. In particular, we apply a compressed powder percolation model to sea ice microstructure that explains the law of fives, the observed behavior (4) of the fluid permeability in the critical temperature regime, as well as data on surface flooding collected recently on sea ice in the Weddell Sea and East Antarctic regions. It was observed in the Arctic (7) that a snow storm and its resultant loading on a sea ice layer can induce a complete upward flushing of the brine network. In the Antarctic, it was observed that the freezing of a surface slush layer, with resultant brine drainage, induced convection within the ice, whereby rejected dense brine is replaced by nutrient-rich sea water ...

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mentioning

confidence: 99%

mentioning

confidence: 99%

The Percolation Phase Transition in Sea Ice

Golden

Ackley

Lytle

1998

Science

448

397

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“…[12,13]. While the model has shown success, there are several shortcomings reported by the literature.…”

Section: Radiative Transfer Inverse Scattering Model (Rtism)mentioning

confidence: 99%

“…However, prior to that, the development of forward models to understand the scattering mechanisms by the different properties of snow and sea ice is needed [1,2]. Then, based on these scattering models, the development of practical methods of inverting observed remote sensing data into proper information on sea ice can be done [3].…”

Section: Introductionmentioning

confidence: 99%

A Study of an Inversion Model for Sea Ice Thickness Retrieval in Ross Island, Antarctica

Lee

Lim²,

Ewe³

2011

PIER

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Abstract-In this study, an inverse microwave scattering model for sea ice has been developed for the purpose of sea ice thickness retrieval using radar backscatter data. The model is loosely based on the Radiative-Transfer-Thermodynamic Inverse Model for Sea Ice Thickness Retrieval from Time-Series Scattering Data. The developed inverse model is a combination of the Radiative Transfer Theory with Dense Medium Phase and Amplitude Correction Theory (RT-DMPACT) forward model and the Levenberg-Marquardt Optimization algorithm. Using input data from ground truth measurements carried out in Ross Island, Antarctica, together with radar backscatter data extracted from purchased satellite images, the sea ice thickness of an area is estimated using the inverse model developed. The estimated sea ice thickness is then compared with the ground truth measurement data to verify its accuracy. The results have shown good promise, with successful estimation of the sea ice thickness within ±0.15 m of the actual measurement. A theoretical analysis has also revealed that the model faces difficulty once the sea ice thickness exceeds 1.7 m. This can be considered in the future development and improvement of the model.

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“…Many forward models based on the Radiative Transfer theory had been developed to achieve this [2][3][4][5][6]. It is important to develop such forward models to understand various scattering mechanisms in the medium and how microwave interacts with different configuration of the medium for better interpretation of satellite images.…”

Section: Introductionmentioning

confidence: 99%

Multilayer Model Formulation and Analysis of Radar Backscattering From Sea Ice

Albert¹,

Lee

Ewe³

et al. 2012

PIER

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Abstract-The Antarctic continent is an extremely suitable environment for the application of remote sensing technology as it is one of the harshest places on earth. Satellite images of the terrain can be properly interpreted with thorough understanding of the microwave scattering process. The proper model development for backscattering can be used to test the assumptions on the dominating scattering mechanisms. In this paper, the formulation and analysis of a multilayer model used for sea ice terrain is presented. The multilayer model is extended from the previous single layer model developed based on the Radiative Transfer theory. The Radiative Transfer theory is chosen because of its simplicity and ability to incorporate multiple scattering effects into the calculations. The propagation of energy in the medium is characterized by the extinction and phase matrices. The model also incorporates the Dense Medium Phase and Amplitude Correction Theory (DM-PACT) where it takes into account the close spacing effect among scatterers. The air-snow interface, snow-sea ice interface and sea ice-ocean interface are modelled using the Integral Equation Method (IEM). The simulated backscattering coefficients for co-and cross-polarization using the developed model for 1 GHz and 10 GHz are presented. In addition, the simulated backscattering coefficients from the multilayer model were compared with the measurement results obtained from Coordinated Eastern Artic Experiment (CEAREX) (Grenfell, 1992) and with the results obtained from the model developed by Saibun Tjuatja (based on the Matrix Doubling method) in 1992.

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Forward electromagnetic scattering models for sea ice

Cited by 48 publications

References 92 publications

The Percolation Phase Transition in Sea Ice

The Percolation Phase Transition in Sea Ice

A Study of an Inversion Model for Sea Ice Thickness Retrieval in Ross Island, Antarctica

Multilayer Model Formulation and Analysis of Radar Backscattering From Sea Ice

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