Ridge density

Technical description - Mean ridge density

Technical description - Minimum ridge density

Technical description - Maximum ridge density

General description

These tables were prepared by Work Package 2 (Box B) as part of INSROP Phase 2 (See Working Paper no. 121). The tables include Year, Month and a number of fields with numeric names. These numbers refer to ship route segments included in the Tbl_1 shapefile set, which is a part of the dataset provided by INSROP Project I.4.2. These segments are an extract of the ship routes as defined in INSROP Working paper no. 108 (1998), prepared by Work Package 1 (Box B) as part of INSROP Phase 2.

Ridge density (parameters 16 - 18)

The initial data for calculating the ridge density (the number of encounters with ridges per 1 km route) are the mean ridge height (parameter 13) and hummock and ridge concentration (the area covered with ridges according to a scale of 1 to 5 units). The following calculation algorithm was used.

A relative ridge area (corresponds to a relative route length in hummocked ice) is determined according to formula (Bushuyev, Loschilov, 1967):

ST = 0.047*T^(4/3) (1)

where ST is a relative area in unit fractions, T is hummock and ridge concentration in conventional units.

The width of the ridge base (BS) is connected with its height (HS) by ratio (Gavrilo, Grischenko, Loschilov, 1974):

BS = 5*Hs (2)

It follows from Equations (1) and (2) that the number of ridges per 1 km route (ridge density) D equals:

D = [47*T^(4/3)] / (5*Hs) (3)

The values of parameters were derived as follows:

- parameter 16 as a mean ridge density observed within a sub-segment during each month of each year;

- parameter 17 as a minimum ridge density observed within a sub-segment during each month of each year;

- parameter 18 as a maximum ridge density observed within the sub-segment during each month of each year.

Technical description - Mean ridge density

Technical description - Mean ridge density for route S by year and month

Technical description - Mean ridge density for route N by year and month

Technical description - Mean ridge density for route S by year and month

Table source file name: p16_s.txt

Path: <NSR_DATA>\icesnow\workpackage2

Table type: DText table.

* Mean ridge density 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: p16_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 - Minimum ridge density

Technical description - Minimum ridge density for route S by year and month

Technical description - Minimum ridge density for route N by year and month

Technical description - Minimum ridge density for route S by year and month

Table source file name: p17_s.txt

Path: <NSR_DATA>\icesnow\workpackage2

Table type: DText table.

* Minimum ridge density 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 ridge density for route N by year and month

Table source file name: p17_n.txt

Path: <NSR_DATA>\icesnow\workpackage2

Table type: DText table.

* Minimum 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 - Maximum ridge density

Technical description - Maximum ridge density for route S by year and month

Technical description - Maximum ridge density for route N by year and month

Technical description - Maximum ridge density for route S by year and month

Table source file name: p18_s.txt

Path: <NSR_DATA>\icesnow\workpackage2

Table type: DText table.

* Maximum ridge density 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 ridge density for route N by year and month

Table source file name: p18_n.txt

Path: <NSR_DATA>\icesnow\workpackage2

Table type: DText table.

* Maximum 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)