scholarly journals Assessing Sensitivity of Hyperspectral Sensor to Detect Oils with Sea Ice

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Bingxin Liu ◽  
Ying Li ◽  
Qiang Zhang ◽  
Liang Han
Keyword(s):  
Sea Ice ◽  
Crude Oil ◽  
Water Surface ◽  
Sea Water ◽  
Spectral Characteristics ◽  
Infrared Region ◽  
Pack Ice ◽  
Assessing Sensitivity ◽  
Oil Type ◽  
Hyperspectral Sensor

The reflectance of two commonly used oils, crude oil and diesel, is measured under various conditions: on a water surface, among pack ice, and on/beneath compact ice. The spectral characteristics of each oil are analyzed using the results from these measures. In conjunction with estimated noise thresholds of the sensor environment, the theoretical potential to identify oil is assessed for the hyperspectral Hyperion. The hyperspectral sensor is more sensitive to the crude oil than to diesel under all conditions. The visible and infrared bands, from 468 nm to 933 nm, are more suitable to identify the crude oil. In addition, when the background is pack ice, the infrared region from 1134 nm to 1326 nm is another potential useful zone. Through the visible-to-infrared bands, the sensitivity to the existence of diesel is inferior to that of crude oil. Relatively, the bands greater than 1134 nm have the potential to separate diesel from the water or sea ice. These characteristics and sensitivity of oil film in terms of ice and oil type can be effectively used to select suitable bands to distinguish oils from sea water and sea ice.

Seasonal variations in the properties and structural composition of sea ice and snow cover in the Bellingshausen and Amundsen Seas, Antarctica

1997 ◽  
Vol 43 (143) ◽  
pp. 138-151 ◽  
Author(s):  
M. O. Jeffries ◽  
K. Morris ◽  
W.F. Weeks ◽  
A. P. Worby
Keyword(s):  
Sea Ice ◽  
Isotopic Composition ◽  
Snow Cover ◽  
Sea Water ◽  
Ice Cores ◽  
Ice Cover ◽  
Snow Accumulation ◽  
Ice Formation ◽  
Frazil Ice ◽  
Core Sets

AbstractSixty-three ice cores were collected in the Bellingshausen and Amundsen Seas in August and September 1993 during a cruise of the R.V. Nathaniel B. Palmer. The structure and stable-isotopic composition (18O/16O) of the cores were investigated in order to understand the growth conditions and to identify the key growth processes, particularly the contribution of snow to sea-ice formation. The structure and isotopic composition of a set of 12 cores that was collected for the same purpose in the Bellingshausen Sea in March 1992 are reassessed. Frazil ice and congelation ice contribute 44% and 26%, respectively, to the composition of both the winter and summer ice-core sets, evidence that the relatively calm conditions that favour congelation-ice formation are neither as common nor as prolonged as the more turbulent conditions that favour frazil-ice growth and pancake-ice formation. Both frazil- and congelation-ice layers have an av erage thickness of 0.12 m in winter, evidence that congelation ice and pancake ice thicken primarily by dynamic processes. The thermodynamic development of the ice cover relies heavily on the formation of snow ice at the surface of floes after sea water has flooded the snow cover. Snow-ice layers have a mean thickness of 0.20 and 0.28 m in the winter and summer cores, respectively, and the contribution of snow ice to the winter (24%) and summer (16%) core sets exceeds most quantities that have been reported previously in other Antarctic pack-ice zones. The thickness and quantity of snow ice may be due to a combination of high snow-accumulation rates and snow loads, environmental conditions that favour a warm ice cover in which brine convection between the bottom and top of the ice introduces sea water to the snow/ice interface, and bottom melting losses being compensated by snow-ice formation. Layers of superimposed ice at the top of each of the summer cores make up 4.6% of the ice that was examined and they increase by a factor of 3 the quantity of snow entrained in the ice. The accumulation of superimposed ice is evidence that melting in the snow cover on Antarctic sea-ice floes ran reach an advanced stage and contribute a significant amount of snow to the total ice mass.

ARCHAEAL ABUNDANCE AND DIVERSITY WITHIN DIFFERENT SECTIONS OF SUMMER SEA-ICE AND SEA WATER IN PRYDZ BAY, ANTARCTICA

2014 ◽  
Vol 25 (2) ◽  
pp. 124-131
Author(s):  
Jifei Ma ◽  
Zongjun Du ◽  
Wei Luo ◽  
Yong Yu ◽  
Yinxin Zeng ◽  
...  
Keyword(s):  
Sea Ice ◽  
Sea Water ◽  
Prydz Bay ◽  
Abundance And Diversity

scholarly journals Meso- and microscale sea-ice motion in the East Siberian Sea as determined from ERS-1 SAR Data

1999 ◽  
Vol 45 (150) ◽  
pp. 370-383 ◽  
Author(s):  
Kim Morris ◽  
Shusun Li ◽  
Martin Jeffries
Keyword(s):  
Time Series ◽  
Sea Ice ◽  
Large Scale ◽  
Vector Fields ◽  
Lateral Displacement ◽  
Motion Vector ◽  
Sar Interferometry ◽  
East Siberian Sea ◽  
Pack Ice ◽  
Sar Data

Abstract Synthetic aperture radar- (SAR-)derived ice-motion vectors and SAR interferometry were used to study the sea-ice conditions in the region between the coast and 75° N (~ 560 km) in the East Siberian Sea in the vicinity of the Kolyma River. ERS-1 SAR data were acquired between 24 December 1993 and 30 March 1994 during the 3 day repeat Ice Phase of the satellite. The time series of the ice-motion vector fields revealed rapid (3 day) changes in the direction and displacement of the pack ice. Longer-term (≥ 1 month) trends also emerged which were related to changes in large-scale atmospheric circulation. On the basis of this time series, three sea-ice zones were identified: the near-shore, stationary-ice zone; a transitional-ice zone;and the pack-ice zone. Three 3 day interval and one 9 day interval interferometric sets (amplitude, correlation and phase diagrams) were generated for the end of December, the begining of February and mid-March. They revealed that the stationary-ice zone adjacent to the coast is in constant motion, primarily by lateral displacement, bending, tilting and rotation induced by atmospheric/oceanic forcing. The interferogram patterns change through time as the sea ice becomes thicker and a network of cracks becomes established in the ice cover. It was found that the major features in the interferograms were spatially correlated with sea-ice deformation features (cracks and ridges) and major discontinuities in ice thickness.

scholarly journals Tank study of physico-chemical controls on gas content and composition during growth of young sea ice

2002 ◽  
Vol 48 (161) ◽  
pp. 177-191 ◽  
Author(s):  
Jean-Louis Tison ◽  
Christian Haas ◽  
Marcia M. Gowing ◽  
Suzanne Sleewaegen ◽  
Alain Bernard
Keyword(s):  
Sea Ice ◽  
Sea Water ◽  
Bubble Nucleation ◽  
Water Dynamics ◽  
Gas Content ◽  
First Year ◽  
Water Interface ◽  
Atmospheric Gases ◽  
Physico Chemical ◽  
Ice Water

AbstractDuring an ice-tank experiment, samples were taken to study the processes of acquisition and alteration of the gas properties in young first-year sea ice during a complete growth–warming–cooling cycle. The goal was to obtain reference levels for total gas content and concentrations of atmospheric gases (O2, N2, CO2) in the absence of significant biological activity. The range of total gas-content values obtained (3.5–18 mL STP kg−1) was similar to previous measurements or estimates. However, major differences occurred between current and quiet basins, showing the role of the water dynamics at the ice–water interface in controlling bubble nucleation processes. Extremely high CO2concentrations were observed in all the experiments (up to 57% in volume parts). It is argued that these could have resulted from two unexpected biases in the experimental settings. Concentrations in bubbles nucleated at the interface are controlled by diffusion both from the ice–water interface towards the well-mixed reservoir and between the interface water and the bubble itself. This double kinetic effect results in a transition of the gas composition in the bubbles from values close to solubility in sea water toward values close to atmospheric, as the ice cover builds up.

scholarly journals East Antarctic sea ice: observations and modelling

1998 ◽  
Vol 27 ◽  
pp. 427-432 ◽  
Author(s):  
Anthony P. Worby ◽  
Xingren Wu
Keyword(s):  
Sea Ice ◽  
Climate Models ◽  
Numerical Models ◽  
Global Climate ◽  
Thickness Distribution ◽  
Ice Thickness ◽  
Antarctic Sea Ice ◽  
Pack Ice ◽  
Concentration Sensitivity ◽  
Sensitivity Studies

The importance of monitoring sea ice for studies of global climate has been well noted for several decades. Observations have shown that sea ice exhibits large seasonal variability in extent, concentration and thickness. These changes have a significant impact on climate, and the potential nature of many of these connections has been revealed in studies with numerical models. An accurate representation of the sea-ice distribution (including ice extent, concentration and thickness) in climate models is therefore important for modelling global climate change. This work presents an overview of the observed sea-ice characteristics in the East Antarctic pack ice (60-150° E) and outlines possible improvements to the simulation of sea ice over this region by modifying the ice-thickness parameterisation in a coupled sea-ice-atmosphere model, using observational data of ice thickness and concentration. Sensitivity studies indicate that the simulation of East Antarctic sea ice can be improved by modifying both the “lead parameterisation” and “rafting scheme” to be ice-thickness dependent. The modelled results are currently out of phase with the observed data, and the addition of a multilevel ice-thickness distribution would improve the simulation significantly.

scholarly journals CHARACTERISTICS OF UHF WAVES DISTRIBUTION IN LAND AND WATER SURFACE TROPOSPHERIC WAVEGUIDE

2019 ◽  
pp. 115-121
Author(s):  
Oxana Vladimirovna Kalambatskaya ◽  
Oleg Nickolaevich Pishchin
Keyword(s):  
Communication Systems ◽  
Water Surface ◽  
Sea Water ◽  
Systems Design ◽  
Cellular Communication ◽  
Effect Of Temperature ◽  
Radio Waves ◽  
Wave Direction ◽  
Surface Atmospheric Layer ◽  
Cellular Communication Systems

The article considers examples of ultra-long propagation of UHF radio waves in mobile cellular communication systems. The phenomena are mainly observed in the Astrakhan region in the spring-summer period (May-June) and are presumably associated with sharp seasonal changes of air temperature followed by rains. The effect of temperature inversion results in changing the refraction index in the surface layer and, as a result, in changing the wave direction as the effect of superrefraction in the surface atmospheric layer. The properties of radio waves in their propagation in the land and sea-water surface waveguide are investigated. The values of the heights of land and sea-water surface tropospheric waveguides for cellular communication systems of different ranges are obtained. The features of existing of tropospheric land and sea-water surface tropospheric waveguides are described. The need to use their properties in the mobile communication systems design is stated.

scholarly journals Phase Relationships in Sea Ice as a Function of Temperature

1976 ◽  
Vol 17 (77) ◽  
pp. 507-519 ◽  
Author(s):  
C. Richardson
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Sea Ice ◽  
Sea Water ◽  
Tabular Form ◽  
Nuclear Magnetic Resonance Spectrometer ◽  
Quantitative Measurements ◽  
Water Based ◽  
Eutectic Concentration ◽  
Phase Relationships

Quantitative measurements of the liquid water phase in a sample of sea ice were made with a nuclear magnetic resonance spectrometer. The measurements are used to compute the phase relationships in sea ice as a function of temperature. A model for sea-water based upon a mixture of seven binary salts is used for these computations. The n.m.r. measurements are related to the solvation water which is associated with each binary salt. This solvation water is bound to the salt in a pseudo-crystalline structure, with the amount of water determined by the eutectic concentration of the salt. The results are given in tabular form and differ somewhat from previously published tables. Two controversial hydrated salts were added to the table, based on the n.m.r. data.

scholarly journals Sea-ice Reconnaissance by Radar

1975 ◽  
Vol 15 (73) ◽  
pp. 215-224 ◽  
Author(s):  
Tadashi Tabata
Keyword(s):  
Sea Ice ◽  
Cross Correlation ◽  
Correlation Method ◽  
Radar Network ◽  
Radar Screen ◽  
Pack Ice ◽  
Ice Field ◽  
Internal Deformation ◽  
Radar Information ◽  
Sea Coast

AbstractTo 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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