Sea-ice Reconnaissance by Radar

Abstract To observe the distribution of pack ice off the coast of the Okhotsk Sea coast of Hokkaido, a radar network consisting of three radar stations was constructed during 1967-69. It covers an area about 70 km wide and 250 km long. The stations are remote-controlled by radio from the Sea Ice Research Laboratory and the information obtained is transmitted back to the laboratory and observed there. Radar has the great advantage of being able to make continuous observations of ice. Usually several special features can be seen on the radar screen, and they are used as markers for the observation of movement. It is ascertained that the average pattern of drift in this area is from north to south-east along the coast line and the ice field undergoes internal deformation during its drift. To get some information on the surface topography of ice from A-scope radar, the intensity of echo signals is classified into 16 steps by computer. To obtain the movement of an ice field from the numerical radar information, a modified two-dimensional cross-correlation method was tested.

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Movements of Marginal Pack Ice Off the Okhotsk Sea Coast of Hokkaido

Annals of Glaciology ◽

10.3189/1985aog6-1-192-195 ◽

1985 ◽

Vol 6 ◽

pp. 192-194

Author(s):

Nobuo Ono

Keyword(s):

Sea Ice ◽

Okhotsk Sea ◽

Radar Network ◽

Pack Ice ◽

Wide Range ◽

Ice Field ◽

Ice Floes ◽

Image Position ◽

Ice Radar ◽

Sea Coast

Movement of pack ice off the Okhotsk Sea coast of Hokkaido was investigated using combinations of sea ice radar photographs and Landsat MSS imageries. The sea ice radar network, consisting of three C-band (5.54 GHz) radar stations, covers an area of about 60 km across and 250 km along the coast. As radar echoes display not the shape of ice floes but the roughness of the ice field, the shapes of floes were drawn on a radar photograph overlaid upon a simultaneous Landsat Fig. 1.The coverage of the sea ice radar network. imagery. Each floe was then traced on the sequential photographs of radar display. The path of each floe frequently indicated a trochoidal oscillation of 18-hour period which is close to the inertial period of this area-Such paths were examined as representing the motion of inertial circle transported upon a long-period movement. The parameter v/U indicates the magnitude of meandering movement of an ice floe within the inertial period, where v is the circumferential velocity of inertial circle motion and U is the average velocity of a main drift in the inertial period. Values of v/U were obtained in a wide range from 0.4 to 8.3 for 18-hour trochoidal paths sampled.

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Movements of Marginal Pack Ice Off the Okhotsk Sea Coast of Hokkaido

Annals of Glaciology ◽

10.1017/s0260305500010326 ◽

1985 ◽

Vol 6 ◽

pp. 192-194

Author(s):

Nobuo Ono

Keyword(s):

Sea Ice ◽

Okhotsk Sea ◽

Radar Network ◽

Pack Ice ◽

Wide Range ◽

Ice Field ◽

Ice Floes ◽

Image Position ◽

Ice Radar ◽

Sea Coast

Movement of pack ice off the Okhotsk Sea coast of Hokkaido was investigated using combinations of sea ice radar photographs and Landsat MSS imageries. The sea ice radar network, consisting of three C-band (5.54 GHz) radar stations, covers an area of about 60 km across and 250 km along the coast. As radar echoes display not the shape of ice floes but the roughness of the ice field, the shapes of floes were drawn on a radar photograph overlaid upon a simultaneous Landsat Fig. 1. The coverage of the sea ice radar network. imagery. Each floe was then traced on the sequential photographs of radar display. The path of each floe frequently indicated a trochoidal oscillation of 18-hour period which is close to the inertial period of this area-Such paths were examined as representing the motion of inertial circle transported upon a long-period movement. The parameter v/U indicates the magnitude of meandering movement of an ice floe within the inertial period, where v is the circumferential velocity of inertial circle motion and U is the average velocity of a main drift in the inertial period. Values of v/U were obtained in a wide range from 0.4 to 8.3 for 18-hour trochoidal paths sampled.

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Periodic Motions in Weddell Sea Pack Ice

Annals of Glaciology ◽

10.1017/s0260305500007114 ◽

1989 ◽

Vol 12 ◽

pp. 145-151 ◽

Cited By ~ 15

Author(s):

M.A. Rowe ◽

C.B. Sear ◽

S.J. Morrison ◽

P. Wadhams ◽

D.W.S. Limbert ◽

...

Keyword(s):

Sea Ice ◽

Austral Summer ◽

Internal Resistance ◽

Longitudinal Component ◽

Weddell Sea ◽

Pack Ice ◽

Position Data ◽

Ice Field ◽

Important Time ◽

Buoy Data

Position data from an Argos-tracked buoy deployed in the southern Weddell Sea in the austral summer of 1986 are analysed to determine important time-scales of variation of sea-ice motion in the seasonal sea-ice zone. Quality control and pre-processing of raw buoy data are discussed. Processed position data are subjected to time- and frequency-domain analyses. These highlight the importance of diurnal and semi-diurnal periodicities in the buoy motion. These preferred periodicities are associated with tidal forcing rather than wind forcing or inertial oscillations. Periodograms of the longitudinal component of buoy motion indicate that the power of the 24 h tidal component drops dramatically around day 130 in 1986. The possible causes of this are discussed and it is concluded that internal resistance within the sea-ice field may have increased at that time.

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Detection of an Ice-Forming Area by Radar and Satellite

Annals of Glaciology ◽

10.1017/s0260305500010508 ◽

1985 ◽

Vol 6 ◽

pp. 252-253 ◽

Cited By ~ 1

Author(s):

Masaaki Aota ◽

Masayuki Oi ◽

Masao Ishikawa ◽

Hiroki Fukushi

Keyword(s):

Sea Ice ◽

Surface Temperature ◽

Satellite Data ◽

Okhotsk Sea ◽

Sea Clutter ◽

Thermal Images ◽

Radar Echoes ◽

Pack Ice ◽

Sea Coast ◽

Infrared Radiometer

This paper describes a method of distinguishing between pack ice and sea clutter in radar echoes, an attempt to roughly estimate the thickness of sea ice from measurement of surface temperature by air-borne infrared radiometer, and an application of thermal images from satellite data to estimate the concentration of sea ice off the Okhotsk Sea coast of Hokkaido.

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Periodic Motions in Weddell Sea Pack Ice

Annals of Glaciology ◽

10.3189/s0260305500007114 ◽

1989 ◽

Vol 12 ◽

pp. 145-151 ◽

Cited By ~ 4

Author(s):

M.A. Rowe ◽

C.B. Sear ◽

S.J. Morrison ◽

P. Wadhams ◽

D.W.S. Limbert ◽

...

Keyword(s):

Sea Ice ◽

Austral Summer ◽

Internal Resistance ◽

Longitudinal Component ◽

Weddell Sea ◽

Pack Ice ◽

Position Data ◽

Ice Field ◽

Important Time ◽

Buoy Data

Position data from an Argos-tracked buoy deployed in the southern Weddell Sea in the austral summer of 1986 are analysed to determine important time-scales of variation of sea-ice motion in the seasonal sea-ice zone. Quality control and pre-processing of raw buoy data are discussed. Processed position data are subjected to time- and frequency-domain analyses. These highlight the importance of diurnal and semi-diurnal periodicities in the buoy motion. These preferred periodicities are associated with tidal forcing rather than wind forcing or inertial oscillations. Periodograms of the longitudinal component of buoy motion indicate that the power of the 24 h tidal component drops dramatically around day 130 in 1986. The possible causes of this are discussed and it is concluded that internal resistance within the sea-ice field may have increased at that time.

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Detection of an Ice-Forming Area by Radar and Satellite

Annals of Glaciology ◽

10.3189/1985aog6-1-252-253 ◽

1985 ◽

Vol 6 ◽

pp. 252-253

Author(s):

Masaaki Aota ◽

Masayuki Oi ◽

Masao Ishikawa ◽

Hiroki Fukushi

Keyword(s):

Sea Ice ◽

Surface Temperature ◽

Satellite Data ◽

Okhotsk Sea ◽

Sea Clutter ◽

Thermal Images ◽

Radar Echoes ◽

Pack Ice ◽

Sea Coast ◽

Infrared Radiometer

This paper describes a method of distinguishing between pack ice and sea clutter in radar echoes, an attempt to roughly estimate the thickness of sea ice from measurement of surface temperature by air-borne infrared radiometer, and an application of thermal images from satellite data to estimate the concentration of sea ice off the Okhotsk Sea coast of Hokkaido.

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Velocidades superficiales del glaciar Upsala, Andes Patagónicos Sur, mediante el uso de correlación cruzada en imágenes satelitales: periodo 2013-2014.

Andean geology ◽

10.5027/andgeov45n1-3034 ◽

2017 ◽

Vol 45 (1) ◽

pp. 87 ◽

Cited By ~ 6

Author(s):

Silvana Moragues ◽

M. Gabriela Lenzano ◽

Andrés Lo Vecchio ◽

Daniel Falaschi ◽

Luis Lenzano

Keyword(s):

Satellite Images ◽

Cross Correlation ◽

Thermal Emission ◽

Correlation Method ◽

Summer Season ◽

Change Processes ◽

Ice Field ◽

The Cross

In this study we present surface velocities estimation for the Upsala glacier catchment, South Patagonian Ice Field (SPI) during the summer season of years 2013 (January-March) and 2014 (March-April), including the Bertacchi, Cono, and Murallón tributaries using satellite images from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER). The Cross-Correlation method was applied by COSI-Corr technique with sub-pixel accuracy. In general, it should be noted that the SPI glaciers, and Upsala glacier in particular, are fast-flowing ice bodies, which makes the technique works properly. Results of surface velocities estimation ranged from 0.22 to 2.93 md-1 for January-March 2013 and 0.12 to 5.8 md-1 for March-April 2014. In summary, COSI-Corr can achieved accurate and reliable results for glacier displacements and surface velocities estimation, also contributing in the better knowledge of the velocities change processes in time, taking into account Upsala is one of the most dynamic temperate glaciers of the SPI.

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Application of cross correlation to HREM images of surfaces

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100128080 ◽

1987 ◽

Vol 45 ◽

pp. 754-755

Author(s):

D. E. Luzzi ◽

L. D. Marks ◽

M. I. Buckett

Keyword(s):

Cross Correlation ◽

A Priori ◽

Matrix Material ◽

Correlation Method ◽

Accurate Knowledge ◽

Complex Image ◽

Fourier Filtering ◽

The Matrix ◽

Low Pass ◽

Data Reduction Technique

As the HREM becomes increasingly used for the study of dynamic localized phenomena, the development of techniques to recover the desired information from a real image is important. Often, the important features are not strongly scattering in comparison to the matrix material in addition to being masked by statistical and amorphous noise. The desired information will usually involve the accurate knowledge of the position and intensity of the contrast. In order to decipher the desired information from a complex image, cross-correlation (xcf) techniques can be utilized. Unlike other image processing methods which rely on data massaging (e.g. high/low pass filtering or Fourier filtering), the cross-correlation method is a rigorous data reduction technique with no a priori assumptions.We have examined basic cross-correlation procedures using images of discrete gaussian peaks and have developed an iterative procedure to greatly enhance the capabilities of these techniques when the contrast from the peaks overlap.

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