Ridge size (height) (parameters 13 - 15)
During the entire period of studies of the Arctic Ocean only fragmentary and
occasional observations of the ridge height were carried out.
First reliable data on the ridge height in the Arctic were reported by Vrangel
(1838) and later by Makarov (1901) and Kolchak (1909). According to Kolchak,
the usual ridge height is 4-6 m. Especially large ridges up to 8 m are noted at
the land fast ice boundary.
From current sources it is known that the mean height of pressure ridges is
1.6 to 1.9 m among first-year ice and 2.0 to 2.5 m in multiyear ice (Gavrilo et
al., 1974).
Vast evidence on the ridge height in the Arctic Basin and the marginal seas
was collected by Romanov (1991) at numerous aircraft landings on the ice during
the 1972 to 1981 period. According to his data, the ridge height decreases, on
average, from the northern shores of the Canadian Arctic archipelago (3-3.2 m)
towards the shores of Siberia (0.8-1 m).
The maximum ridge height reaches 3 m in the Barents and Kara Seas , 4-5 m in
the north of these seas and 1-5 m in the East-Siberian and Laptev Seas: 1-3 m in
first-year ice and 3.1-5.5 m in multiyear ice (Romanov, 1991).
In some cases data on mean multiyear ridge height might be insufficient. The
required information on the mean and maximum ridge height for different seasons
and regions can be obtained on the basis of statistics and a probability
theory. For this purpose one can use the relations between the ridge height and other
ice cover characteristics which were either observed on a regular basis or
reliably calculated.
Determination of mean ridge height (parameter 13)
Mean ridge height HS in the regions of the Arctic Basin and the marginal seas
was calculated on the basis of data (Romanov, 1991) on mean ice thickness hS
and the ratio of the mean ridge height to the thickness of ambient level ice
(Table 8.5). The four lower lines of the table contain data of shipborne
observations (Frolov, pesonal communication).
Table 8.5. Mean ice thickness hS, the ratio HS/hS and mean ridge height HS
Ridge height
| Region
| hs, cm
| Hs/hs
| Hs, cm
|
| Northern Barents Sea
| 145
| 0.86
| 125
|
| South-western Kara Sea
| 120
| 1.10
| 132
|
| Kara Sea
| 148
| 0.93
| 138
|
| Western Laptev Sea
| 184
| 0.99
| 182
|
| Laptev Sea
| 157
| 0.98
| 154
|
| East-Siberian Sea
| 213
| 0.89
| 190
|
| Chukchi Sea
| 155
| 1.11
| 172
|
| Beaufort Sea
| 334
| 0.65
| 217
|
| Arctic Basin (near the pole)
| 310
| 0.77
| 239
|
| Arctic Basin (north of the Siberian coast and Vrangel Island)
| 241
| 0.86
| 207
|
| Kara Sea (land fast ice)
| 180
| 0.68
| 122
|
| Laptev Sea (land fast ice)
| 195
| 0.64
| 125
|
| East-Siberian Sea (land fast ice)
| 206
| 0.67
| 138
|
| Pechora Sea
| 45
| 1.55
| 70
|
| Zhelaniya Cape region
| 112
| 1.00
| 112
|
| Vilkitsky Strait (land fast ice)
| 176
| 0.70
| 124
|
| North-eastern Kara Sea (land fast ice)
| 168
| 0.55
| 93
|
This dependence can be represented in the analytical form by the following formula, according to which parameter 13 was calculated for each sub-segment:
Hs = n * hs^m (1),
where HS and hS are expressed in cm, the parameters m and n are determined by the least squares method:
- for drifting ice m = 0.62, n = 6.59
- for land fast ice m = 0.94, n = 0.88
Technical description - Mean ridge heightTechnical description - Mean ridge height for route S by year and month
Technical description - Mean ridge height for route N by year and month Technical description - Mean ridge height for route S by year and month
Table source file name: p13_s.txt
Path: <NSR_DATA>\icesnow\workpackage2
Table type: DText table.
* Mean ridge height 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 ridge density for route N by year and month
Table source file name: p13_n.txt
Path: <NSR_DATA>\icesnow\workpackage2
Table type: DText table.
* Mean ridge density 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 - Max. ridge height (1% exceedance prob.)
Technical description - Max. ridge height (1% exceedance prob.) for route S by year and month
Technical description - Max. ridge height (1% exceedance prob.) for route N by year and month Technical description - Max. ridge height (1% exceedance prob.) for route S by year and month
Table source file name: p14_s.txt
Path: <NSR_DATA>\icesnow\workpackage2
Table type: DText table.
* Max. ridge height (1% exceedance prob.) 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 - Max. ridge height (1% exceedance prob.) for route N by year and month
Table source file name: p14_n.txt
Path: <NSR_DATA>\icesnow\workpackage2
Table type: DText table.
* Max. ridge height (1% exceedance prob.) 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 - Max. ridge height (0.1% exceedance prob.)
Technical description - Max. ridge height (0.1% exceedance prob.) for route S by year and month
Technical description - Max. ridge height (0.1% exceedance prob.) for route N by year and month Technical description - Max. ridge height (0.1% exceedance prob.) for route S by year and month
Table source file name: p15_s.txt
Path: <NSR_DATA>\icesnow\workpackage2
Table type: DText table.
* Max. ridge height (0.1% exceedance prob.) 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 ridge density for route N by year and month
Table source file name: p15_n.txt
Path: <NSR_DATA>\icesnow\workpackage2
Table type: DText table.
* Mean ridge density 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)