Study of Snow Cover Profile
© Alexsander S. Bogolyubov,
© Michael J. Brody, USA,
This manual describes
the main functions and features of snow cover, and a procedure for snow survey along a
landscape profile. The activity includes location of survey sites, establishment of snow
exploring shaft, determination of snow layers according to a number of visual
characteristics, their measurement and description.
This field study has instructional video
featuring real students conducting the ecological field techniques in nature. Each video
illustrates the primary instructional outcomes and the major steps in accomplishing the
task including reporting the results.
One of the most important landscape characteristics in winter are the properties of
snow cover Ц its thickness and density, as well as depth of the frost zone at
different sites. It is well known that preservation of seeds and sprouts from winterkill
as well as the wintering success of many animal species depends on the depth of the soil
Depth of the seasonal frost zone is of great importance, as it influences
peculiarities of spring soil erosion causing destruction of soil structure. Unfortunately,
the study of permafrost is complicated by its laboriousness and use of specific equipment,
for example, the soil probe. Thus, this educational activity will be focused on snow Ц
i.e. peculiarities of its distribution along the relief forms and under different
vegetation types, structure of snow cover and study of snow's role in landscape function.
The activity is aimed at revealing the dependence of the thickness and structure
of snow cover upon relief forms and vegetation type. It is known that snow
cover is thinner and distributed unevenly in coniferous forests.
In contrast, the distribution of snow in deciduous forests is thicker and more evenly
distributed. In comparing a forest and an open site, it turns out that wind is much
lighter in forests than in open areas, so snow is not blown off the soil surface. Thus,
snow cover in forests is characterized by a more even distribution than in the field, for
instance, where wind differentiates thickness of the snow cover by stripping rises and
filling up relief depressions with snow.
In order to complete the task, students will require shovels (for unearthing snow),
rulers (it is recommended to use long rulers Ц for the full depth of the snow cover) or
measuring tapes, description forms (soil description forms can be used) or field logs,
compasses and some other materials at hand (sticks, blades and matches).
The teacher should explain the main functions and properties of the snow cover before
the activities, and students should be taught how to measure and describe the snow cover
prior to independent studies.
Main functions of snow cover
The role of snow in the function of an environment is especially obvious when air
temperature falls below zero degrees centigrade. In areas where there is no snow in cold
seasons, soil gets frozen through for many meters, and, for instance, in Yakutia, the
depth of permafrost makes up one and a half kilometer.
The preservative function of snow or thermal insulation is, perhaps, the most
important one. It is known that snow cover has loose structure due to the different shapes
of snowflakes. Interstices among snowflakes are filled up with air that is characterized
by low heat conductivity, so we owe such a wonderful property of snow to
air. The air, as we sometimes (but incorrectly) say, Уwarms up well.Ф
Due to the low heat conductivity of snow, day-to-day temperature variation penetrates
into the snow cover only for a depth of 24 centimeters on average. As specific research
has shown, if the amplitude of temperature fluctuation reaches 30 degrees at the snow
surface, then at 5 cm depth it amounts to only 16 degrees, at 24 cm depth it makes up 3
degrees and at 44 cm depth the amplitude is insignificant Ц 0.8 degrees.
Not just soils are protected from frost penetration due to snow as mentioned above, but
plants as well, which can stay green through the winter. They often serve as the only food
for animals, and harbor seeds, which serve as security for renewal of the vegetation cover
However, snow is known not only for its heat insulating function. As snow is water in
solid aggregative state, it accumulates in large quantities and remains until
spring in order to water the earth and allow plants to start growing when it becomes warm.
Besides heat insulating and accumulating functions, snow cover also exerts influence
upon a climate.
Everyone knows that air masses move around the earth's surface. Coming from remote
areas, they bring along characteristics of the area they originated from Ц mainly air humidity
and temperature. As they move above the surface continuously, they change slightly;
however, if they stagnate in one area for a certain time, they acquire temperature and
moisture characteristics of the given region.
It is also known that air cannot be heated directly by the sun. Sunlight is absorbed by
a surface and then the surface gives heat back to the air in the form of infrared
radiation. Some solar radiation is reflected by the surface in the form of light and is
not transformed into heat. The less is the surface reflection power and the higher its
absorption capacity, the warmer the surface becomes. Thus, surface temperature depends on
its reflection properties, or albedo.
The albedo of a black body is equal to 0%, whereas the albedo of a white body is equal
to 100%. Fresh-fallen snow is very close to 100% according to its albedo. Correspondingly,
when the ground is covered with snow, the ground cannot warm up air ...
This was only the first page from the manual and its full version you can see in the
Ecological Field Studies Techniques Video 4CD Set:
It is possible to purchase the complete set of 40 seasonal Ecological Field
Studies Techniques Video (in mpg format) in an attractive 4 compact disk set.
These compact disks are compatible with Mac and PC computers.
The videos are suitable for individual student or whole class instruction. To purchase the complete 4CD set
write to firstname.lastname@example.org in a free form.
Ecological Field Studies Demo Disk:
We also have a free and interesting demonstration disk that explains our ecological field studies approach.
The demo disk has short excerpts from all the seasonal field study videos as well as sample text from all the teacher manuals.
The disk has an entertaining automatic walk through which describes the field study approach and explains how field studies meet education standards.
You can also download the Demo Disc from ecosystema.ru/eng/eftm/CD_Demo.iso.
This is a virtual hybrid (for PC and Mac computers) CD-ROM image (one 563 Mb file "CD_Demo.iso").
You can write this image to the CD and use it in your computer in ordinary way.
You also can use emulator software of virtual CD-ROM drive to play the disk directly from your hard disk.