Snow and ice

Total mercury concentrations in Siberian snow ranged between 8.0 and 60.0 ng/L the maximum methylmercury concentration was 0.25 ng/L. 

In general, soil mercury concentrations were higher in the vicinity of acetaldehyde plants. 

Jamaican agricultural soils contained up to 0.83 mg total mercury/kg DW, mean 0.221 mg/kg DW this was far in excess of Danish and Canadian guidelines for mercury in crop soils, i.e, 0.007 mg/kg DW. Jamaican soils also exceeded Danish and Canadian proposed limits for arsenic, cadmium, copper, and chromium in agricultural soils. 

Mercury-sensitive ecosystems are those where comparatively small inputs or inventories of total mercury, i.e., 1.0-10.0 g Hg/ha, result in elevated concentrations of methylmercury in natural resources these systems are characterized by efficient conversion of inorganic mercuric mercury to methylmercury sufficient to contaminate aquatic and wildlife food webs. Known sensitive ecosystems include surface waters adjoining wetlands, low alkalinity or low pH lakes, wetlands, and flooded terrestrial areas. 

Total mercury concentrations in uncontaminated natural waters (presumably unfiltered) now range from about 1.0 to 50.0 ng/L. Concentrations as high as 1100.0 ng/L are reported in freshwaters near active gold mining facilities in Ecuador, and up to 450,000.0 ng/L in drainage water from abandoned mercury 

---

While pressure melting may be important for snow and ice near 0°C, it is possible that even here an alternative explanation will prove important. Ice is a substance of unusual structural complexity, and it has been speculated that a liquidlike surface layer is present near the melting point [17,18] if this is correct, the low /t values observed at low sliding speeds near 0°C may be due to a peculiarity of the surface nature of ice rather than to pressure melting. 

Includes crop and pasture land and farmsteads, strip mines, permanent snow and ice, and land that does not fit iato any other land cover. 

Highway. Rock salt, solar salt, and in some cases in Europe, evaporated salt are used to maintain traffic safety and mobiUty during snow and ice conditions in snowbelt regions throughout the world. Sodium chloride melts ice at temperatures down to its eutectic point of —21.12°C. Most snowstorms occur when the temperature is near 0°C, where salt is very effective. More than 40% of dry salt produced in the United States is used for highway deicing. 

The volume of the freshwater amounts to only one-thirtieth of the 1.25 x 10 km (300 x 10 mi ) of the water ia salty oceans. Approximately one-third of the freshwater exists permanently as snow and ice (3). A large portion of the remaining freshwater has infiltrated too far underground or is partially polluted with minerals and chemicals and therefore is not readily usable. The entire life system on the earth depends on the remaining freshwater sources therefore, it is essential to protect the quaUty of the available waters. 

Economic Aspects and Uses. Total production of calcium chloride in 1989 was 873,000 tons (31). Most of this was produced from Michigan brines. The principal use of calcium chloride is to melt snow and ice from roads. It is also used in dust control, concrete setting control, and various industrial uses. 

The portion of the incoming radiation reflected and scattered back to space is the albedo. The albedo of clouds, snow, and ice-covered surfaces... 

The Leblanc process was replaced by the ammonia soda (Solvay - 1860 ) process, in which sodium chloride brine is treated with ammonia and carbon dioxide to produce sodium bicarbonate and ammonium chloride. Sodium carbonate is obtained from the bicarbonate by heating. Ammonium chloride treated with lime gives calcium chloride and ammonia. The chlorine in the original salt becomes calcium chloride that is used for melting snow and ice. The ammonia is reused in the process (99.9% recovery). 

Five components of the hydrosphere play major roles in climate feedbacks - atmospheric moisture, clouds, snow and ice, land surface, and oceans. Changes to the hydrologic cycle, among other things, as a result of altered climate conditions are then referred to as responses. Interactions with climate can best be explored by examirung potential response to a climate perturbation, in this case, predicted global warming. 

Another family of feedbacks arises because the radical differences in the albedo (reflectivity) of ice, snow, and clouds compared to the rest of the planetary surface, which causes a loss of the absorption of solar radiation and thereby cools the planet. Indeed, the high albedo of snow and ice cover may be a factor that hastens the transition into ice ages once they have been initiated. Of course, the opposite holds due to decreasing albedo at the end of an ice age. As simple as this concept may appear to be, the cloud-albedo feedback is not easy to quantify because clouds reflect solar radiation (albedo effect) but absorb... 

Wania F, Hoff JT, Jia CQ, et al. 1998. The effects of snow and ice on the environmental behaviour of hydrophobic organic chemicals. Environ Pollut 102 25-41. 

Today there is a renewed interest in snow and ice cooling. The first large-scale plant for space cooling is now in its sixth year of operation. Several... 

The albedo of earth surface varies from about 0.1 for the oceans to 0.6-0.9 for ice and clouds which mean the clouds, snow and ice are good radiation reflectors while liquid water is not. In fact, snow and ice have the highest albedos of any parts of the earth s surface Some parts of Antarctic reflect up to 90% of incoming solar radiation. 

Changes in climate dramatically alter the planets snow and ice covered cryosphere. 

If snow/ice is stored indoor it is done in a more or less insulated building. In a cavern no insulation except the ground is needed. When the snow/ice is stored on ground or in ponds it is necessary with thermal insulation, henceforth denoted insulation. Both natural and artificial snow and ice may be used and there is no size limitation for snow cooling systems. This snow cooling plant in Sundsvall is an open pond with larger pieces of wood chips as thermal insulation. 

Snow is normally defined as precipitation formed of ice crystals and ice as solid water with hexagonal structure and density about 920 kg m-3. In snow storage the main issue is to have enough amounts of frozen water at low cost why the only relevant distinction is the density. If natural snow or ice is too expensive or not available in enough quantity, it is possible to produce frozen water. Artificial snow and ice made with different types of water sprayers, including snow blowers (snow guns). The production rate depends on equipment, relative air humidity, and temperatures of the air and water. 

There are a number of suggested and implemented techniques of snow and ice storage for cooling applications. In Japan about 100 projects have been realized during the last 30 years, and in China there is about 50-100 snow and ice storage systems (Kobiyama, 2000). Also Canada, USA and Sweden have made efforts in the field. Below both realised and suggested techniques are presented. 

A number of different open pond snow and ice storage techniques have been suggested. In Ottawa a storage for 90,000 m3 of snow in an abandoned rock quarry (120 x 80 x 9.5 m3, L x W x H), was studied. The mean cooling load was 7,000 kW. A light colored PE plastic tarpaulin was suggested as insulation, with melt water re-circulation for cold extraction. The estimated payback time was 10 years (Morofsky, 1981). 

Different snow and ice making systems have been tested. The first years both fan type snow guns and one LowEnergyTower were used. The fan-type machines required a lot of maintenance and surveillance the first years and a lot of the snow from the LowEnergyTower landed outside the storage. The last year s two fan type snow guns have been used, mounted on 5 m high towers and now only operated in the wind direction. This worked well. 

Suzuki, T., S. Kobayashi, K. Tsushima, S. Shao, Y. Teng, and G. Liu, 1997. A case study on the utilization of snow and ice as natural cold energy source for low-temperature storage materials, Snow Engineering, pp. 553-558, ISBN 90 5410 865 7. 

Acid Rain. Acid rain is a broad term used to refer to acid fallout of the atmosphere in the form of rain, snow, and ice (see Textbox 74) (Bubernick... 

Significant economies of computation are possible in systems that consist of a one-dimensional chain of identical reservoirs. Chapter 7 describes such a system in which there is just one dependent variable. An illustrative example is the climate system and the calculation of zonally averaged temperature as a function of latitude in an energy balance climate model. In such a model, the surface temperature depends on the balance among solar radiation absorbed, planetary radiation emitted to space, and the transport of energy between latitudes. I present routines that calculate the absorption and reflection of incident solar radiation and the emission of long-wave planetary radiation. I show how much of the computational work can be avoided in a system like this because each reservoir is coupled only to its adjacent reservoirs. I use the simulation to explore the sensitivity of seasonally varying temperatures to such aspects of the climate system as snow and ice cover, cloud cover, amount of carbon dioxide in the atmosphere, and land distribution. 

Raynaud, D., Delmas, R., 1977, Proceedings of the Grenoble Symposium 1975, Isotopes and Impurities in Snow and Ice, IAHS-AISH publication, 1J8, 377. 

In summary, a number of chemical constituents in polar snow and ice have seasonal concentration variations that make them suitable for dating ice cores by counting annual layers. In... 

---