Multiscale Surface Roughness and Backscattering

Manninen, Albert

doi:10.2528/pier96060700

Cited by 22 publications

(12 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Since the rms height and correlation length of Baltic sea ice obviously depend on the measured distance, it is not possible to directly apply analytic methods such as the Integral Equation Method (IEM) for estimating the backscattering coefficient Fung, 1994]. An attempt has been made lately to extend IEM (the method for calculating the backscattering coefficient for rough surfaces) to multiscale roughness cases, but the low value of the dielectric constant of the Baltic sea ice limits the validity of the IEM seriously [Fung, 1994, Manninen, 1996. However, various ice types can be distinguished by the interdependence of the large-scale rms height and correlation length values as is shown in Figures 21 and 27.…”

Section: Discussionmentioning

confidence: 99%

Surface roughness of Baltic sea ice

Manninen¹

1997

J. Geophys. Res.

Self Cite

View full text Add to dashboard Cite

Abstract. Small-, medium-, and large-scale measurements of sea ice surface roughness were carried out in the Baltic Sea over a 3-year period. A clear relationship was found between the rms height and correlation length of Baltic sea ice. In most cases the surface correlation function was close to exponential. The logarithm of rms height showed a linear dependence on that of measured distance. Similarly, the correlation length was in many cases linearly dependent on the measured distance. This dependence on length suggests that ice surface roughness could be characterized as a fractal. Surface roughness is usually described with rms height •r and correlation length L. Actually, these are pseudoparameters, as they depend on the measured length [Church, 1988]. For conventional surfaces the dependence is sometimes so weak that these parameters can be taken as constants, but this is not so with fractal-like surfaces. Rms height and correlation length can be determined also for fractal-like surfaces but will not then represent intrinsic surface properties and will depend on the measurement process used. Fractal surfaces will typically have measured correlation lengths, which are of the same order as the measured length no matter what length is used. In nature the fractal characteristics of a surface will not extend to infinity; there is an upper limit to the measurement length, the surpassing of which leads to saturation of the rms height and correlation length values. The surface then behaves like a random Gaussian surface with a very high maximum surface height difference. The adequate surface roughness description to be chosen depends on the application in question. If the surface area to be characterized is smaller than required for the saturation of the conventional roughness parameters, the effect of measurement length cannot be neglected. Field ExperimentsThe years 1992 and 1993 were very mild, making ice measurements possible only in the Bay of Bothnia (Figure 1). In 1994 the ice extent was mostly very close to average for the Baltic Sea, and measurements were accordingly carried out in the Bay of Bothnia, the Sea of Bothnia, and the Gulf of Finland. The ice types were also much more varied in 1994 than during the previous 2 years.In 1992, measurements were carried out mostly in ridged old ice areas, with ice blocks in the ridges some 40 cm thick. Because the whole ice field was deformed repeatedly, no large level ice areas were available for comparison. In 1993 the study area was the edge of an old, many times deformed ice field (Figure 2). Here the ice block thickness was typically about 20 cm.In 1994, surface roughness measurements were carried out on old level ice and deformed areas in the Bay of Bothnia and the Gulf of Finland. The ice field of the Sea of Bothnia was newer and had deformed radically about 1 week prior to the field experiment. The deformation appeared in the Bay of Bothnia and the Gulf of Finland either as long ridge sails, rubble fields (Figure 3), or consolidated pancake ice. The ice in ...

show abstract

Section: Discussionmentioning

confidence: 99%

Surface roughness of Baltic sea ice

Manninen¹

1997

J. Geophys. Res.

Self Cite

View full text Add to dashboard Cite

show abstract

“…The sea surface is fully described by its directional height spectrum S(k, φ), which can be derived from time series measurements [31]. However, a simplified description involving fewer parameters can also be used.…”

Section: Sea Surface Characteristicsmentioning

confidence: 99%

Retrieval of Significant Wave Height and Mean Sea Surface Level Using the GNSS-R Interference Pattern Technique: Results From a Three-Month Field Campaign

Alonso-Arroyo

Camps

Park

et al. 2015

IEEE Trans. Geosci. Remote Sensing

View full text Add to dashboard Cite

Abstract-Since 1993, when the European Space Agency (ESA) proposed the use of GNSS reflected signals for sea mesoscale altimetry, a wide range of applications have appeared. This work focuses on the retrieval of Significant Wave Height (SWH) and the Mean Sea Surface Level (MSSL) from a ground-based experiment using the Interference Pattern Technique (IPT). Two different observables on the IPT are analyzed: the oscillation frequency, and the angle where coherency is lost. The point where coherency in the reflection process is lost can be related to the Rayleigh criterion for smooth surfaces and helps to determine the SWH. Spectral analysis on the interference pattern helps to determine the MSSL. A three-month field campaign was performed on the "Pont del Petroli" pier, Badalona, Spain, to see how the reflected GNSS signals were affected by coastal sea state, and check previous assumptions. Results from this field experiment are shown confirming that the SWH can be retrieved with an accuracy of 6 cm and the MSSL with 4 cm. Estimations of both parameters are obtained every 30 minutes approximately.

show abstract

“…According to in situ measurements [32] and [33], the fractal dimension D of natural soil surface profiles is usually smaller than about 1.5.…”

Section: Numerical Results and Discussmentioning

confidence: 99%

Bistatic Scattering From Rough Dielectric Soil Surface With a Conducting Object With Arbitrary Closed Contour Partially Buried by Using the FBM/Saa Method

Li¹

2007

PIER

View full text Add to dashboard Cite

Abstract-A hybrid approach of the forward-backward method (FBM) with spectral accelerate algorithm (SAA) and Monte Carlo method is developed in this paper. It is applied to numerical simulation of bistatic scattering from one-dimensional arbitrary dielectric constant soil surface with a conducting object with arbitrary closed contour partially buried under both the horizontal and vertical polarization tapered wave incidence at low grazing angle. The energy conservation has been checked for the FBM/SAA. Numerical simulations of bistatic scattering at low grazing angle have been discussed in this paper.

show abstract

Multiscale Surface Roughness and Backscattering

Cited by 22 publications

References 15 publications

Surface roughness of Baltic sea ice

Surface roughness of Baltic sea ice

Retrieval of Significant Wave Height and Mean Sea Surface Level Using the GNSS-R Interference Pattern Technique: Results From a Three-Month Field Campaign

Bistatic Scattering From Rough Dielectric Soil Surface With a Conducting Object With Arbitrary Closed Contour Partially Buried by Using the FBM/Saa Method

Contact Info

Product

Resources

About