Sea ice is frozen sea water. Salt ions in the water complicate the growth of ice crystals, and makes sea ice much more dynamic than freshwater ice. Sea ice covers nearly 7% of the Earth's surface, has a huge effect on global climate, and is one of the largest, single biomes on Earth.
Ice is the solid, crystalline form of water, which solidifies at 0ºC. Roughly 9 polymorphs of ice are defined, only one, however, occurs naturally on Earth. This common form of ice is known as ice 1h, and its lattice displays six-fold rotational symmetry.
The incorporation of sea salt or other ions in the crystal lattice of ice faces both size and charge restrictions, thus the salt and water do not form solid solution. This means that as the ice grows, the ions are rejected and most of them are returned to the water. Some, however, are retained within the ice matrix as liquid inclusions; creating a network of channels through with this brine travels.
The network of channels and associated brine inclusions greatly contribute to what makes sea ice different from freshwater ice. These inclusions change the deformational, thermal, and optical properties of ice; making sea ice unique in several different ways.
Growth of Sea Ice
* The latent heat of freezing, or the enthalpy of freezing, for the phase transition from water to ice is 334J/g for pure water and just slightly lower for sea water.
* The energy (heat) released from the freezing layer of water is conducted through the ice and released into the atmosphere.
* The thermal properties of the ice and snow cover, as well as the energy balance at the top and bottom of the growing ice sheet determine the rate at which heat can be pushed out.
* For an ice surface that is in thermal equilibrium with the atmosphere, conservation of energy mandates that the heat must flux in and out of the ice .
* This can be expressed mathematically, and using calculus techniques the thickness to which an ice sheet can grow can be predicted for given surface temperature conditions.
Motion
* Sea ice does not float freely on the polar oceans , but rather is moved around, tossed about, and deformed as a result of several forces which act on the ice pack.
a) physical and chemical changes related to tides, waves, currents, sea level and ice cap variations, upwelling, and salinity variations;
- Glaciers flow under the force of gravity as snow accumulates on the upper parts of the glacier and wants moves down slope.
2. What is the difference between a's By increasing the temperature of the ice. 3. What is the difference between a'smart' and a By increasing the pressure only really significant in reactions. involving gases in the process).
The planet we live in, the earth is a tiny composition in this huge universe. It has diversities ranging from highly variant temperature and pressure belts as well as various ecosystem types. One such remarkable feature of the earth is the polar ice caps. There are three major prominent features, the Antarctic ice on the South Pole, the Arctic ice on the North Pole and Greenland on the north between North America and Europe. Antarctica consist about 90 percent of the world's ice (and 70 percent of its fresh water). It is covered with ice an average of 2,133 meters (7,000 feet) thick. If all of the Antarctic ice melted, sea levels around the world would rise about 61 meters (200 feet). The Arctic ice is not so thick in comparison and it mostly floats in the Arctic Ocean. Greenland, on the other hand would add another 7 meters (20 feet) to the oceans if it melted because Greenland is closer to the equator than Antarctica, the temperatures there are higher, so the ice is more likely to melt. Scientists from the Universities of London and Edinburgh say that ice loss in Antarctica and Greenland together contribute approximately 12 percent of the rise in sea levels. The melting of these enormous ice bodies can significantly impact the global changes in climate and reversely, this climate changes also impact the melting of the ice bodies. It is a two way process and the causes are mostly anthropogenic.
The solutions with ice and salt were all able to drop to a temperature below 0°C within 10 minutes, while the ice solution never dropped below 0°C across all 5 trials. This indicate that salt is the variable that contributed to the decrease in temperature since the initial temperature of the thermometer, the amount of ice, and the room temperature, were all held constant.
The ice sheet extends from about 60° to 83°N over a distance of 2,400 km in the North Atlantic Ocean. The ice sheet covers 1.71 million km2 , or roughly 80% of the surface of Greenland. It consists of a northern dome and a southern dome, with maximum elevations of 3,230 m and 2,850 m, respectively, linked by a long saddle with elevations around 2,500 m. Its total volume is about 2.85 million km3, which, if it were to melt entirely, would raise global sea level by about 7.2 m. The ice sheet has an average thickness of 1,670 m and reaches a maximum of 3,300 m in the center. The bedrock surface below the ice sheet is an extensive flat area near sea level, which would rebound by as much as 1,000 m if the ice sheet were to be removed (Figure 1). Precipitation over Greenland generally decreases from south to north, ranging from about 2,500 mm per year in the southeast to less than 150 mm per year in interior northeastern Greenland. The southern high precipitation zone is largely determined by the Icelandic low and the resulting onshore flow which is forced to ascend the surface of the ice sheet. In contrast to Antarctica, summer temperatures on Greenland are high enough to cause widespread summer melting. This results in an ablation zone with negative mass balance all around its perimeter. Ablation rates are highest over the southwestern part of the ice sheet where...
Pressure on the ice reduces the melting point. If pressure is afterward reduced, water will freeze again. This is called regelation. When a player skates across the ice, he or she applies a lot of pressure, leaving a trail of water where the blades were. Because the pressure leaves quickly, the water freezes to ice again (Haché 22). Nevertheless, pressure is not the only factor that causes this melting. Friction also takes part because it creates heat. With help...
Bintanja, R., G.J. Van Oldenborgh, S. S. Drijfhout, B. Wouters, and C. A. Katsman. "Important Role for Ocean Warming and Increased Ice-shelf Melt in Antarctic Sea-ice Expansion." Nature.Com. 2013 Macmillan Publishers Limited, 31 Mar. 2013. Web. 17 Mar. 2014.
fishes habitat and property. But with less ice, it can help ships travel longer during the
Chasing Ice covers the long debated topic of global warming and whether or not human activity is currently causing global temperatures to rise. Evidence suggests that increased carbon dioxide emissions over the past couple hundred years are responsible for the warming of the Earth’s surface, and thus increasing the levels of the ocean due to an accelerated rate of ice melting. We discussed this same topic in class and how humans are contributing to the greenhouse effect which plays a large role in trapping these unnatural amounts of gases such as carbon dioxide in the Earth’s atmosphere and causing a rise in the number of natural disasters around the world.
Introduction: A phase change is a result from the kinetic energy (heat) either decreasing or increasing to change the state of matter (i.e. water, liquid, or gas.) Thus saying, freezing is the phase change from a liquid to a solid which results from less kinetic energy/heat. Also, melting is the phase change from a solid to a liquid which results from adding kinetic energy/heat. So, the freezing and melting point of something is the temperature at which these phase changes occur. Therefore, a phase change will occur when a vial of 10 mL of water is placed into a cup of crushed ice mixed with four spoonfuls with 5 mL of sodium chloride for 30 minutes. If 10 mL of water is placed in an ice bath, it will then freeze at 5 degrees Celsius because the kinetic energy will leave quicker with the ice involved. The purpose of this lab is to observe what temperature the water must be to undergo a phase change.
Heat is thermal energy being transferred from one place to another, because of temperature changes. This can take place by three processes. These three processes are known as conduction, convection, and radiation.
molecules its size it would have a boiling point of -75øC and a freezing point of -125øC4.
Currently, scientists believe that once an ice age has been triggered, oceanic circulation currents can change and the mixing of the oceans cools the southern hemisphere. As glaciers begin to accumulate in the northern hemisphere, solar heat is reflected off the snow which leads to further cooling.
Ocean water is often referred to as salt water. Ocean water becomes salty as water flows in rivers, it picks up small amount of mineral salts form rocks and soil of the riverbeds. This very-slightly salty water flows into the oceans. The water in the oceans only leaves by evaporating, but the salt remains dissolved in the ocean, it does not evaporate. So the remaining water gets saltier and saltier as time goes on.