For calculating the parameters (7 - 9) connected with the ice thickness the
initial data described in Section 8.4.2 were used. For the summer period the data
on the ice melting stages over the 1954 to 1986 period were used.
Ice melting stages present a characteristic which was determined during visual
airborne observations according to the national scale units (from 0 to 5). The
ice melting stage equaling 0, means that melting indications are absent, 5
units mean that ice has strongly decayed and almost disappeared.
The methods for calculating the parameters in the summer and winter differed:
the calculations for the summer months (June-September) took into account the
thickness decrease due to ice melting. For this purpose an empirical dependence
between the relative thickness change in the process of melting - deltaH/H and
the ice melting stage was used - R (Appel, Gudkovich, 1977):
R = 11.1 - 10 / (0.9025 + 1.02*deltaH/H) (1)
From Equation (1) the expression for calculating the ice thickness (Hp) can be
derived:
Hp = Hv - 0.9025*R*Hv / (11.322 + 1.02*R) (2),
where Hv is the ice thickness of a definite age category in May (by the end of
the period of growth).
Equation (2) allows taking into account the ice thickness changes due to
melting from the top in close ice. With appearance of open water zones among ice the
process of melting becomes more rapid due to the heat absorbed by water. For
taking this effect into account the following formula was used:
p = 0.1*[N + (1-N)*k]*Hp (3),
where N is ice concentration in tenths; Hp is the ice thickness calculated by
formula (2); k is a non-dimensional coefficient (Table 8.4).
Table 8.4. The k coefficient values in June-September
Ice thickness (calculated)
| Concentration
| June
| July
| August
| September
|
| 10/10
| 1.0
| 1.0
| 1.0
| 1.0
|
| 9/10
| 0.975
| 0.95
| 0.925
| 0.90
|
| 8/10
| 0.95
| 0.90
| 0.85
| 0.80
|
| 7/10
| 0.925
| 0.85
| 0.775
| 0.70
|
| 6/10
| 0.90
| 0.80
| 0.70
| 0.60
|
| 5/10
| 0.875
| 0.75
| 0.625
| 0.50
|
| 4/10
| 0.85
| 0.70
| 0.55
| 0.40
|
| 3/10
| 0.825
| 0.65
| 0.475
| 0.30
|
| 2/10
| 0.80
| 0.60
| 0.40
| 0.20
|
| 1/10
| 0.775
| 0.55
| 0.325
| 0.10
|
| 0/10
| 0.75
| 0.50
| 0.25
| 0.00
|
After estimating the ice thickness of each age category observed within a sub-segment, the values of parameters were calculated:
- parameter 7 as a weighted thickness mean of all age categories observed taking into account their partial concentration;
- parameter 8 as the least thickness of all age categories observed;
- parameter 9 as the largest thickness of all age categories observed.
Technical description - Mean ice thicknessTechnical description - Mean ice thickness for route S by year and month
Technical description - Mean ice thickness for route N by year and month Technical description - Mean ice thickness for route S by year and month
Table source file name: p07_s.txt
Path: <NSR_DATA>\icesnow\workpackage2
Table type: DText table.
* Mean ice thickness for route S by year and month
447 records, 144 descriptive fields.
Fields: [<Name>] -- <Alias> (type of field)
[Year] -- "Year" (Numeric, no decimals)
[Month] -- "Month" (Numeric, no decimals)
[1] -- "1" (Numeric, no decimals)
...
[142] -- "142" (Numeric, no decimals)
Technical description - Mean ice thickness for route N by year and month
Table source file name: p07_n.txt
Path: <NSR_DATA>\icesnow\workpackage2
Table type: DText table.
* Mean ice thickness for route N by year and month
447 records, 132 descriptive fields.
Fields: [<Name>] -- <Alias> (type of field)
[Year] -- "Year" (Numeric, no decimals)
[Month] -- "Month" (Numeric, no decimals)
[201] -- "201" (Numeric, no decimals)
....
[330] -- "330" (Numeric, no decimals)
Technical description - Minimum ice thickness
Technical description - Minimum ice thickness for route S by year and month
Technical description - Minimum ice thickness for route N by year and month Technical description - Minimum ice thickness for route S by year and month
Table source file name: p08_s.txt
Path: <NSR_DATA>\icesnow\workpackage2
Table type: DText table.
* Minimum ice thickness for route S by year and month
447 records, 144 descriptive fields.
Fields: [<Name>] -- <Alias> (type of field)
[Year] -- "Year" (Numeric, no decimals)
[Month] -- "Month" (Numeric, no decimals)
[1] -- "1" (Numeric, no decimals)
...
[142] -- "142" (Numeric, no decimals)
Technical description - Minimum ice thickness for route N by year and month
Table source file name: p08_n.txt
Path: <NSR_DATA>\icesnow\workpackage2
Table type: DText table.
* Minimum ice thickness for route N by year and month
447 records, 132 descriptive fields.
Fields: [<Name>] -- <Alias> (type of field)
[Year] -- "Year" (Numeric, no decimals)
[Month] -- "Month" (Numeric, no decimals)
[201] -- "201" (Numeric, no decimals)
....
[330] -- "330" (Numeric, no decimals)
Technical description - Maximum ice thickness
Technical description - Maximum ice thickness for route S by year and month
Technical description - Maximum ice thickness for route N by year and month Technical description - Maximum ice thickness for route S by year and month
Table source file name: p09_s.txt
Path: <NSR_DATA>\icesnow\workpackage2
Table type: DText table.
* Maximum ice thickness for route S by year and month
447 records, 144 descriptive fields.
Fields: [<Name>] -- <Alias> (type of field)
[Year] -- "Year" (Numeric, no decimals)
[Month] -- "Month" (Numeric, no decimals)
[1] -- "1" (Numeric, no decimals)
...
[142] -- "142" (Numeric, no decimals)
Technical description - Maximum ice thickness for route N by year and month
Table source file name: p09_n.txt
Path: <NSR_DATA>\icesnow\workpackage2
Table type: DText table.
* Maximum ice thickness for route N by year and month
447 records, 132 descriptive fields.
Fields: [<Name>] -- <Alias> (type of field)
[Year] -- "Year" (Numeric, no decimals)
[Month] -- "Month" (Numeric, no decimals)
[201] -- "201" (Numeric, no decimals)
....
[330] -- "330" (Numeric, no decimals)