A_Ch4_Snow&Ice

= Changes in the Cryosphere =

Vocabulary:
=4.1:=
 * Lake ice: ice that forms on the surface of lakes
 * Sea ice: ice that forms in seas
 * Glaciers: A slowly moving mass of ice originating from an accumulation of snow.
 * Ice cap: A thick mass of glacial ice and snow that permanently covers an area of land.
 * Ice shelves: A thick mass of ice that is permanently attached to the land but projects into and floats on the sea.
 * Ice sheet: A broad, thick piece of ice covering an extensive area for a long period of time.
 * Latent heat: Heat absorbed or radiated during a change of phase at constant temperature or pressure.
 * Phase change: A change from one state (solid or liquid or gas) to another without change in chemical composition.
 * Surface energy: Surface energy quantifies the disruption of intermolecular bonds that occur when a surface is created.
 * Ice jams: Blockages formed by accumulation of broken ice

=4.2:=
 * Albedo: The proportion of the incident light or radiation reflected by a surface
 * Atmospheric circulation: Atmospheric circulation is the large-scale movement of air, and the means (together with the smaller ocean circulation) by which thermal energy is distributed on the surface of the Earth
 * Snow water equivalent: Water equivalent (or content) of the snow on the ground (i.e. snow depth)
 * Meteorologists: One who reports and forecasts weather conditions.
 * Radiometer:An instrument for detecting or measuring the intensity or force of radiation.

=4.3: Changes in River and Lake Ice = Freeze up dates- The official date in which the concentration of ice to water reaches 30%

Break up dates- The date in which the ice starts breaking up and moving downstream

** 4.4 Changes in sea ice **
Ice Albedo feedback- the positive feedback of the reflection of radiation caused by snow covered land, ice caps, glaciers and sea ice. The more quantity of reflection, the greater positive feed back and visa versa.

Ice edge- the polar coordinated in which the concentration of ice to water is 30%.

Ice extent- The extent at which the Ice edge reaches. =4.5:= = =

=4.6:=

=4.7-4.8:=
 * Frozen Ground: includes near-surface soil affected by short-term freeze-thaw cycles, seasonally frozen ground and permafrost.
 * Subsea (offshore) Permafrost: permafrost ice that exists in the polar regions in continental shelves beneath the seabed.
 * Permafrost Degradation: refers to a naturally or artificially caused decrease in the thickness and/or areal extent of permafrost.
 * //in situ //: means to examine the phenomenon exactly in place where it occurs (i.e. without moving it to some special medium).
 * Erosion: the gradual breakdown of something; to wear away at.
 * Seasonally Frozen Ground: the soil layer that freezes and thaws annually. It has no regard, and is not affected by the presence, or lack there of, of an underlying permafrost layer of soil.
 * <span class="NormalTextRun SCX259387145" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 16px;">Borehole(s): a drilled hole into the ground to obtain samples for geological study; used for mining as well.
 * <span style="background-color: transparent; color: #000000; display: block; font-family: 'Segoe UI',Tahoma,Verdana,sans-serif; font-size: 8px; text-align: left; vertical-align: baseline;"><span class="SpellingError SCX259387145" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 16px;">Cryosphere <span class="NormalTextRun SCX259387145" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 16px;">: frozen part of Earth: the frozen part of the Earth's surface, including the polar ice caps, continental ice sheets, glaciers, sea ice, and permafrost <span class="EOP SCX259387145" style="font-family: Book Antiqua,Serif; font-size: 16px;">.

** 4.1: Introduction **
Snow ice, river ice, lake ice, sea ice, glaciers and ice caps, ice shelves, ice sheets, and frozen ground are the main components of the cryosphere. After the ocean, the cryosphere is the second largest component of the climate system. This is because of its ice mass and heat capacity. Physical properties of the cryosphere such as its high surface reflectivity and the latent heat associated with physical changes which impact the surface energy greatly, is the basis of its climate variability and change. When there is an increase in meridonal temperature difference, snow and ice in polar regions becomes present and vis versa, if there is a decrease in meridonal temperature difference then there will be an absence of snow and ice in polar regions. This decrease or increase in the meridonal temperature difference affects winds and ocean currents. Elements of the cryosphere are found at all latitudes, creating a near global assessment of cryosphere-related climate changes.

This picture shows that cryosphere lays on top of the low terrain.

The section of the cryosphere that resides on the land stores 75% of Earths freshwater. Changes in the ice mass on land has played a big role in the recent changes of sea level. Approximately 7 m to 57 m of sea level rise is equivalent to the volumes of the Greenland and the Antarctic ice sheets. Glaciers and ice caps have a big part in the availability of freshwater. The amount of ice mass on land changes the levels on the sea.

10% of Earths surface is permanently covered in ice. The ice caps and glaciers outside of Antarctica and Greenland only cover a tiny fraction of that 10%. In the season of winter, snow covers about 49% of land in the Northern Hemisphere. Frozen ground is the largest part of the Cryosphere. Ice doesn't only cover the land; it also covers parts of the ocean. About 7% of the oceans are covered in ice. Depending on their dynamic and thermodynamic characteristics, changes in the Cryosphere happen at different times. All the different components of the Cryosphere causes changes such as short term change in climate, with permafrost, ice shelves, and ice sheets; also long term changes like the ice-age.

This picture show, and somewhat describes the components of the cryosphere and how long the components stay on the surface of the Earth.

The role of snow in the climate system includes positive feedback related to albedo and different, weaker feedbacks that correspond with moisture storage, letent heat and insulation of the underlying surface. They vary with latitude during the season. From November to April, snow covers more than 33% of Earths surface North of the equator and can reach up to 49% in January.

Most rivers and lakes start to become covered in ice in the winter.Although ice has the smallest area and volume of the other components of the cryosphere, it plays a very important role in freshwater ecosystems, winter transportation, bridge and pipeline crossings and so on. If changes occurring in the ice cover such as thickness and duration, it can take its toll on both the natural environment and human activity's.When river ice breaks up, it is usually followed by ice jams. These jams aren't good. They can hinder the flow of water and lead to severe flooding.

"At maximum extent arctic sea ice covers more than 14 x 10^6 km^2, reducing to only 7 x 10^6 km^2 in the summer", 6th paragraph, 1st sentence of 4.1 introduction. Antarctic sea ice is seasonal. There is two type of sea ice; sea ice that last under a year called ‘first-year ice’ and sea ice that lasts longer than one year called ‘multi-year ice’. Most sea ice is part of what is called ‘pack ice’, which circulates the polar oceans, driven by winds and currents. Pack ice is extremely diverse, with its difference in ice thickness and age, snow cover, etc.

Ice caps and glaciers comply to changes in climate more quickly than an ice sheet can. This is because their ratio of annual mass turnover and their total mass is higher than that of an ice sheet. Changes in climate result in changes in glaciers and ice caps as well as changes in sea level. They can also affect the freshwater availability. As ice caps and glaciers melt, it causes little ice ages around the large lakes in the mountains especially in the Himalayas and Andes.

http://www.youtube.com/watch?v=_swZ-pIAqEw

The main reservoirs capable of affect the sea level are the ice sheets in Greenland and Antarctica. Ice that forms due to snowfall spreads towards the coast where it melts into the ocean and forms an iceberg. In the past it was thought that the spreading velocity would not change so that the impacts of changes in climate could be estimated by changes in snowfall and surface melting. That thought has changed with strong belief that floating ice sheets control the motion of glaciers which accelerates them after an ice shelve breakup.

Frozen ground isn’t just the frozen ground, it also includes permafrost. Frozen ground is the single largest component of the cryosphere. Permafrost acts to record air temperature and snow ground variations and when climate change is happening, permafrost can be involved in feedbacks related to moisture and greenhouse gas exchange with the atmosphere.

In this section it mostly discussed how the components of the cryosphere effect our world and the climate. I am effected by this because if something bad happens to our ecosystem because of something in the cryosphere such as the glaciers melting or the polar ice caps melting, its practically unchangable. =**4.2: Changes in snow cover**= 4.2.1 Background: Since snow has a high albedo it influences the surface energy budget and on Earths radiative balance. Snow albedo depends on the depth of the snow as well of its age, the vegetation height, and the amount of incoming solar radiation and cloud cover. In a case where the albedo of snow decreases it usually is caused by anthropogenic soot. With snow-albedo feedback aside, snow can influence the climate through other indirect feedbacks. <span style="font-family: Calibri,sans-serif; font-size: 11pt;">4.2.2 Source of Snow Data: Many methods have been used to do daily observations of snow depth and new snow fall in different countries, dating back to the late 1800’s. In the 1950’s, the measurements of snow depth and snow water equivalent became more widespread.
 * REFLECTION:**

The weekly visible wavelength satellite maps of NH snow cover, produced by the US National Oceanic and Atmospheric Administration’s (NOAA) National Environmental Satellite Data and Information Service, is the premier data set used to evaluate large scale snow covered areas. These maps are valuate over a surface observation.

=**4.3:** Changes in River and Lake Ice = Freeze up and Breakup dates of rivers are important for maintaining temperature, radiative forcing and changes in snow fall. Freeze up date are marked as the time at which a continuous and immobile ice forms; however this date ranges from local observations of the presence or lack of ice to inferring the measurements of river discharge. Breakup dates are noted upon when the ice cover begins to move downstream or when open water becomes extensive at the location measurements were taken. Records of these dates say that freeze up dates have become later at a rate of 5.8 ± 1.6 days per century (note: ± is plus or minus) and break up days occurred earlier at a rate 6.5 ± 1.2 days per century. The graph shows two lines per body of water representing the freeze up and break up dates as proceeding from 1845 to 1995. The progression of later freeze up dates and earlier break up dates are represented greatly by the Red River. The graph lines of the Red River show that the freeze up and breakup dates are progressing towards each other.

Reflection:
Changes in River and Lake Ice, as we had learned, are one of things caused by global warming. Other than that we learned little to nothing in this topic. We had learned that rivers form from watersheds which are cause from runoff water from mountain precipitation, snow melting or just precipitation. From there we had learned about the transition of water to ice which related to Freeze up and Breakup dates. This data clearly shows that global warming is causing a shorter overall time of when the river or lake is frozen.

In the future this may affect me in the case that it helps reflect the suns energy. If this happened to disappear, this overall only account for a tiny percentage of sun reflected therefore, this has little effect on my life.

=**4.4:Changes in sea ice**= Sea ice forms at the polar oceans and are necessary for the global climate system. It is central to the ice-albedo feedback mechanism that enhances climate repose at high altitudes. The ice-albedo feedback is the positive feedback of the reflection of radiation caused by snow covered land, ice caps, glaciers and sea ice. Sea ice is also essential for the exchange of heat, gases and momentum between the atmosphere and polar oceans. An important indicator of the climate condition is the thickness of sea ice. The ice grows thicker as bottom freezing balances heat conduction through the ice to the surface. Nearly half of the volume of ice is due to ice sheets rafting on top of each other causing it to form sinuous ‘ridges’ of thick ice.

Some climatically important characteristics of sea ice are concentration (the fraction of ocean covered by ice), its extent (the area enclosed by ice edge), the total area of ice within its extent, the area of multi-year ice within the total extent, its thickness, its velocity, and its growth and melt rates. Ice extent may be amplified by the ice-albedo feedback. Ice extent is recorded using passive microwave satellites. Estimation of sea ice properties from passive microwave emission requires an algorithm to convert observed radiance into ice concentration. These algorithms have an accuracy of a 5% error. During melt season this can be extent to 10 to 20% error. Such records show that there is a significant decreasing trend in artic sea ice extent by -2.7 ± 0.6% per decade (top graph). In the Antarctic there is a small positive feed of 0.47 ± 0.8% per decade (bottom graph).

This was taken by annual mean values while the blue line shows decadal variations. NH is the northern hemisphere (artic) and SH is the southern hemisphere (Antarctic). This picture shows the Northern hemisphere's melting ice caps. www.youtube.com/watch?v=fj999LIWvJk The video above shows the shrinking Ice Albedo due to the melting ice caps.

==== There isn't enough information on the thickness of ice to infer any conclusions, But there are small fluctuations in the thickness in the arctic ice. The information for the graph was acquired with satellite radar or laser alimentary The graph below shows the variations in the thickness of the ice over a time of 50 years. There is a small fluctuation over the period of time, but it shows no type of pattern. ====

The graph above is a measurement of annual mean average sea ice thickness anomaly. The various lines are from the multiple models used in the measurement. Ice motion, tracked using microwave sensors, are too varied and show no pattern. In ice export and advection shows that 14% of the sea ice is exported through the Fram Straight. Sonar observations of ice exports, based on geostrophic wind, show no trends. A pair of scientist assembled a 47 year time series of ice area and volume flux of the ice proceeding through the Fram Straight. They found an annual area flux of 919 x 103 yr-1 and the annual volume flux of 2366 km3 as shown on the top (area) and middle (volume). (According to a reading on Columbia.edu I think the NAO index (bottom graph) is the surface pressure on the water). Overall there is low frequency variability in the pattern of sea ice motion to find a significant trend.

==

Reflection
The set of data seemed to be inconclusive and most of it lacked much pattern. One of the things that had any conclusions to it was the decrease of the ice extent in the magnetic South Pole and the slow increase in the magnetic North Pole. In relation to class work, we had little to no previous knowledge of this topic, but that global warming causes it and basic knowledge of water.

This may someday be of a problem. The northern icecap is melting rather quickly and that would flood Florida, New York, The Amazon River, most of Europe and parts of japan. It would also cause temperatures to rise as the ice-Albedo takes a negative turn. =**4.5:**=

=**4.6:**=

**4.7 - HannahLee Ferus.**
<span style="background-color: transparent; color: #000000; display: block; font-family: 'Segoe UI',Tahoma,Verdana,sans-serif; font-size: 8px; text-align: left; vertical-align: baseline;"><span class="NormalTextRun SCX39273097" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 16px;">4.71 <span style="background-color: transparent; color: #000000; display: block; font-family: 'Segoe UI',Tahoma,Verdana,sans-serif; font-size: 8px; text-align: left; vertical-align: baseline;"><span class="NormalTextRun SCX39273097" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 16px;">_ <span style="background-color: transparent; color: #000000; display: block; font-family: 'Segoe UI',Tahoma,Verdana,sans-serif; font-size: 8px; text-align: left; vertical-align: baseline;"><span class="NormalTextRun SCX39273097" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 16px;">Frozen ground is the single largest component of the <span class="SpellingError SCX39273097" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 16px;">cryosphere <span class="NormalTextRun SCX39273097" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 16px;">. The presence of frozen ground is highly dependent on the temperature of the ground, as well as local factors; vegetation conditions, amount of snow, and the physical and thermal properties of soils, as well as the soils moisture conditions.

<span style="background-color: transparent; color: #000000; display: block; font-family: 'Segoe UI',Tahoma,Verdana,sans-serif; font-size: 8px; text-align: left; vertical-align: baseline;"><span class="NormalTextRun SCX39273097" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 16px;">The thawing of ice-rich permafrost can lead to subsidence of the ground surface as masses of ground ice areas melt, as well as the formation of uneven topography, <span class="SpellingError SCX39273097" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 16px;">thermoskarst <span class="NormalTextRun SCX39273097" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 16px;">, and infrastructure change to ecosystems.

<span style="background-color: transparent; color: #000000; display: block; font-family: 'Segoe UI',Tahoma,Verdana,sans-serif; font-size: 8px; text-align: left; vertical-align: baseline;"><span class="NormalTextRun SCX39273097" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 16px;">The presence or absence of permafrost, and the thickness of the active layer, are the primary controls of a lands local hydrological process; particularly in the northern regions of Earth.

<span style="background-color: transparent; color: #000000; display: block; font-family: 'Segoe UI',Tahoma,Verdana,sans-serif; font-size: 8px; text-align: left; vertical-align: baseline;"><span class="NormalTextRun SCX39273097" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 16px;">Seasonal freezing and thawing of the soil is the process which has influences on spatial patterns, seasonal to inter-annual variability, and long-term trends in terrestrial carbon budgets and surface-atmosphere trace gas exchange. These occur directly through biophysical controls on photosynthesis as well as respiration and indirectly through controls on availability of soil nutrients.

<span style="background-color: transparent; color: #000000; display: block; font-family: 'Segoe UI',Tahoma,Verdana,sans-serif; font-size: 8px; text-align: left; vertical-align: baseline;"><span class="NormalTextRun SCX39273097" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 16px;">4.7.2.1

<span style="background-color: transparent; color: #000000; display: block; font-family: 'Segoe UI',Tahoma,Verdana,sans-serif; font-size: 8px; text-align: left; vertical-align: baseline;"><span class="NormalTextRun SCX39273097" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 16px;">Temperature monitoring of permafrost, at <span class="SpellingError SCX39273097" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 16px;">hydrometeorological <span class="NormalTextRun SCX39273097" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 16px;"> stations in Russia started in the 1950's at depths of ~3.2 m (__m__eters). Since the 1940's in northern Alaska temperature measurements have also been taken in boreholes greater that are 100 m deep, as well as deep boreholes which are generally greater than (>)200 m in depth. Measurements have been taken from shallow boreholes since the 1980's throughout Alaska, as well as measurements in northern Canada, Europe, and the Tibetan Plateau; throughout the late 1900's.

<span style="background-color: transparent; color: #000000; display: block; font-family: 'Segoe UI',Tahoma,Verdana,sans-serif; font-size: 8px; text-align: left; vertical-align: baseline;"><span class="NormalTextRun SCX39273097" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 16px;">4.7.2.2

<span style="background-color: transparent; color: #000000; display: block; font-family: 'Segoe UI',Tahoma,Verdana,sans-serif; font-size: 8px; text-align: left; vertical-align: baseline;"><span class="NormalTextRun SCX39273097" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 16px;">In recent decades in the northern hemisphere (NH) the permafrost has a trend of warming. Some sites in the NH have had little warming, or even a cooling trend. Temperatures of permafrost have an increase range of anywhere from 0.2 <span class="NormalTextRun SCX39273097" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 12.6667px; vertical-align: super;">o <span class="NormalTextRun SCX39273097" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 16px;">C - 4 <span class="NormalTextRun SCX39273097" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 12.6667px; vertical-align: super;">o <span class="NormalTextRun SCX39273097" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 16px;">C. The depths of temperature measurements, that were then compared to other data as regional trends, have been taken over the past decades from shallow depths of 1-2 m up to 20 and 30 m throughout the NH.

<span style="background-color: transparent; color: #000000; display: block; font-family: 'Segoe UI',Tahoma,Verdana,sans-serif; font-size: 8px; text-align: left; vertical-align: baseline;"><span class="NormalTextRun SCX126067011" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 16px;">4.7.2.3 <span style="background-color: transparent; color: #000000; display: block; font-family: 'Segoe UI',Tahoma,Verdana,sans-serif; font-size: 8px; text-align: left; vertical-align: baseline;"><span class="NormalTextRun SCX126067011" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 16px;">_

<span style="background-color: transparent; color: #000000; display: block; font-family: 'Segoe UI',Tahoma,Verdana,sans-serif; font-size: 8px; text-align: left; vertical-align: baseline;"><span class="NormalTextRun SCX126067011" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 16px;"> To this day the southern boundary of the discontinuous permafrost zone in North America has moved northward in response to the land warming after the Little Ice Age. <span style="background-color: transparent; color: #000000; display: block; font-family: 'Segoe UI',Tahoma,Verdana,sans-serif; font-size: 8px; text-align: left; vertical-align: baseline;"><span class="NormalTextRun SCX126067011" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 16px;">In more recent years, warming and thawing of permafrost is a widespread issue on the Tibetan Plateau, China, as well. <span style="background-color: transparent; color: #000000; display: block; font-family: 'Segoe UI',Tahoma,Verdana,sans-serif; font-size: 8px; text-align: left; vertical-align: baseline;"><span class="NormalTextRun SCX126067011" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 16px;">On the Tibetan Plateau along the Qinghai-Xizang Highway, areal extent of permafrost islands decreased approximately 36% over the past three (and almost a half) decades. <span style="background-color: transparent; color: #000000; display: block; font-family: 'Segoe UI',Tahoma,Verdana,sans-serif; font-size: 8px; text-align: left; vertical-align: baseline;"><span class="NormalTextRun SCX126067011" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 16px;">A thaw settlement is the downward displacement of soil when ice rich permafrost thaws. These thaw settlements do not occur uniformly, so it creates a chaotic surface with small hills and wet depressions known as <span class="SpellingError SCX126067011" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 16px;">thermokarst <span class="NormalTextRun SCX126067011" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 16px;"> terrain. This sort of terrain is particularly common in areas underlain by wedges of ice. <span style="background-color: transparent; color: #000000; display: block; font-family: 'Segoe UI',Tahoma,Verdana,sans-serif; font-size: 8px; text-align: left; vertical-align: baseline;"><span class="NormalTextRun SCX126067011" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 16px;"> Mechanical discontinuities in the substrate, lead to active-layer detachment slides. These then have the capacity to damage structures similar to other types of rapid mass movements that occur on slopes of thawing ice-rich permafrost layers that are near the surface.

<span style="background-color: transparent; color: #000000; display: block; font-family: 'Segoe UI',Tahoma,Verdana,sans-serif; font-size: 8px; text-align: left; vertical-align: baseline;"><span class="NormalTextRun SCX126067011" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 16px;">Erosion is another aspect of the changes to the ice and permafrost. Ice-bearing permafrost, by the Arctic Ocean alone, has a mean annual erosion rate of from 2.5 to 3.0 m <span class="SpellingError SCX126067011" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 16px;">yr <span class="NormalTextRun SCX126067011" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 12.6667px; vertical-align: super;">–1 <span class="NormalTextRun SCX126067011" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 16px;"> for the ice-rich coasts to 1.0 m <span class="SpellingError SCX126067011" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 16px;">yr <span class="NormalTextRun SCX126067011" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 12.6667px; vertical-align: super;">–1 <span class="NormalTextRun SCX126067011" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 16px;"> for the ice-poor permafrost coasts along the Russian Arctic Coast.

<span style="background-color: transparent; color: #000000; display: block; font-family: 'Segoe UI',Tahoma,Verdana,sans-serif; font-size: 8px; text-align: left; vertical-align: baseline;"><span class="NormalTextRun SCX126067011" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 16px;">The melting and erosion of ice layers, of any sort, causes the water level in many areas throughout the world to rise. Ex., in the past three decades the total lake area of continuous permafrost zones in Siberia increased by 12%, and the lake number itself rose 4%.

<span style="background-color: transparent; color: #000000; display: block; font-family: 'Segoe UI',Tahoma,Verdana,sans-serif; font-size: 8px; text-align: left; vertical-align: baseline;"><span class="NormalTextRun SCX126067011" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 16px;">Significant change, world wide, of seasonally frozen ground have been observed.

<span style="background-color: transparent; color: #000000; display: block; font-family: 'Segoe UI',Tahoma,Verdana,sans-serif; font-size: 8px; text-align: left; vertical-align: baseline;"><span class="NormalTextRun SCX126067011" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 16px;">47.3.1.

<span style="background-color: transparent; color: #000000; display: block; font-family: 'Segoe UI',Tahoma,Verdana,sans-serif; font-size: 8px; text-align: left; vertical-align: baseline;"><span class="NormalTextRun SCX126067011" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 16px;">The layer of soil that is considered the active layer is the portion of soil that is above the permafrost layer, and which thaws and freezes seasonally; plays an important part in the cold regions. Ecological, hydrological, biogeochemical, and <span class="SpellingError SCX126067011" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 16px;">pedogenic <span class="NormalTextRun SCX126067011" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 16px;"> processes all take place within this active layer. <span style="background-color: transparent; color: #000000; display: block; font-family: 'Segoe UI',Tahoma,Verdana,sans-serif; font-size: 8px; text-align: left; vertical-align: baseline;"><span class="NormalTextRun SCX126067011" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 16px;">When this active layer changes, or is changed, the thermal and physical properties on the surface are affected. <span style="background-color: transparent; color: #000000; display: block; font-family: 'Segoe UI',Tahoma,Verdana,sans-serif; font-size: 8px; text-align: left; vertical-align: baseline;"><span class="NormalTextRun SCX126067011" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 16px;">Monitoring of this layer was not developed on a global scale <span class="SpellingError SCX126067011" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 16px;">intil <span class="NormalTextRun SCX126067011" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 16px;"> the 1990's. Up until then, the only stations were scarce, and were in Russia. Like other ice, permafrost, and soil observations, the active layer is viewed, and information is taken through the use of boreholes.

<span style="background-color: transparent; color: #000000; display: block; font-family: 'Segoe UI',Tahoma,Verdana,sans-serif; font-size: 8px; text-align: left; vertical-align: baseline;"><span class="NormalTextRun SCX126067011" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 16px;">More than 125 sites now exist in the Arctic and Antarctic to observe the response of the active layer and of near-surface permafrost to climate change.

<span style="background-color: transparent; color: #000000; display: block; font-family: 'Segoe UI',Tahoma,Verdana,sans-serif; font-size: 8px; text-align: left; vertical-align: baseline;"><span class="NormalTextRun SCX126067011" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 16px;">European monitoring sites indicated that the active layer was the greatest thickness (>) in the summers of 2002-2003. Since the 1980's, the average thickness of the active layer has also increased by up to 1.0 m over the Tibetan Plateau.

<span style="background-color: transparent; color: #000000; display: block; font-family: 'Segoe UI',Tahoma,Verdana,sans-serif; font-size: 8px; text-align: left; vertical-align: baseline;"><span class="NormalTextRun SCX126067011" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 16px;">4.7.3.2

<span style="background-color: transparent; color: #000000; display: block; font-family: 'Segoe UI',Tahoma,Verdana,sans-serif; font-size: 8px; text-align: left; vertical-align: baseline;"><span class="NormalTextRun SCX126067011" style="background-color: transparent; color: #000000; font-family: Book Antiqua,Serif; font-size: 16px;">Seasonal frozen ground has decreased rapidly all over the world. more than .34 m from 1956-1990 in Russia. and the estimated maximum extent of seasonally frozen ground in the NH has decreased 7% from 1901-2002. With a decrease in the spring of up to 15% as well.

**4.8**
<span style="background-color: transparent; color: #000000; display: block; font-family: 'Segoe UI',Tahoma,Verdana,sans-serif; font-size: 8px; text-align: left; vertical-align: baseline;"><span class="NormalTextRun SCX25387364" style="background-color: transparent; color: #000000; font-family: Times New Roman,Serif; font-size: 16px;">The <span class="SpellingError SCX25387364" style="background-color: transparent; color: #000000; font-family: Times New Roman,Serif; font-size: 16px;">cryosphere <span class="NormalTextRun SCX25387364" style="background-color: transparent; color: #000000; font-family: Times New Roman,Serif; font-size: 16px;"> has undergone significant changes. The retreat of arctic se ice, especially in the summer; the continuing decrease of size of mountain glaciers; and over all decreasing in amounts of solidified water and ice structures.

<span style="background-color: transparent; color: #000000; display: block; font-family: 'Segoe UI',Tahoma,Verdana,sans-serif; font-size: 8px; text-align: left; vertical-align: baseline;"><span class="NormalTextRun SCX25387364" style="background-color: transparent; color: #000000; font-family: Times New Roman,Serif; font-size: 16px;">The problem is that the glaciers and large packs of ground snow and ice are hard to measure because of their natural life cycle (spring-smaller, winter-larger).

<span class="NormalTextRun SCX25387364" style="background-color: transparent; color: #000000; font-family: Times New Roman,Serif; font-size: 16px;">In spite of the large uncertainties, the data that are available portray a rather consistent picture of a <span class="SpellingError SCX25387364" style="background-color: transparent; color: #000000; font-family: Times New Roman,Serif; font-size: 16px;">cryosphere <span class="NormalTextRun SCX25387364" style="background-color: transparent; color: #000000; font-family: Times New Roman,Serif; font-size: 16px;"> and its decline over the 20th century, increasingly so during 1993 to the present.

=Bibliography:= http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch4.html

4.1
http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch4s4-1.html

4.2
http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch4s4-2.html http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch4s4-2-2.html

4.3
http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch4s4-3.html http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch4s4-3-2.html

4.4
http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch4s4-4.html http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch4s4-4-2.html http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch4s4-4-2-2.html http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch4s4-4-2-3.html http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch4s4-4-3.html http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch4s4-4-3-2.html http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch4s4-4-3-3.html http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch4s4-4-3-4.html http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch4s4-4-3-5.html http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch4s4-4-3-6.html http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch4s4-4-3-7.html http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch4s4-4-4.html http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch4s4-4-4-2.html http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch4s4-4-4-3.html

4.7
http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch4s4-7.html

4.8
http://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch4s4-8.html