1. Stages of melting in Russian ice practices
IICWG-III, DNMI, Tromso,
Stages of melting in Russian ice practices
Vasily Smolyanitsky,
Arctic and Antarctic Research Institute

2. Stages of melting on ice charts
In Russian national ice practice since 1940
Russian national scale of ice melting was standardized and included into Manuals of air reconnaissance since 1950s
Obligatory both for airborne, shipborne and coastal observations, are observed in summer time (from mid-May till mid-September)
From 1981 both Russian national and WMO scales are in use
Depicted in special rectangular symbol under the main circular one with total and partial concentrations
For analysis purposes observations of stages of melting were extracted from the basic detailed ice charts and a separate set of maps was constructed
Utilized in empirical relationships describing ship motion

3. WMO and Russian national stages of melting correspondence
Stages of melting in Russian and WMO nomenclature
Differences between Russian national and WMO stages of melting definitions
Utilizes 5 codes scale (0-5) for first and multiyear ice and 3 codes (0-3) for young ice with intermediate values (e.g. 1-2 or 3-4)
Recorded and depicted separately for multiyear, firstyear and young ice
WMO and Russian national stages of melting correspondence
Stage of melt
WMO Nomenclature code (WMO-259, 1970)
Closest code(s) from Russian national nomenclature
No melt
Few puddles 1
Many puddles 2
Flooded ice 3
2,3
Few thawholes 4
3,4
Dried ice 5
Rotten ice
6,7

4. Stages of melting depiction on detailed ice chart
Sample detailed ice map for Pechora sea; stages of melting depicted in rectangular symbol under ice concentration in circular symbol separately for first-year and young ice
0-1 – stage of melting for the older thin first year ice, 2 – stage of melting for the young ice

5. Stages of melting data Coverage for 1953-1980 (ratio in % of observed to potentially available)
June
July
August

6. Stages of melting mean values for 1953-1980
June
July
August

7. Stages of melting modal values for 1953-1980
June
July
August

8. Suggestions: A. Stages of melting are representing thermal surface processes and surface features, are modulated by ice melt and occur in summer time (late May - early September). The proposed "Strength index" looks to represent volume processes and features, seems to be modulated by a greater number of processes – ice melt, changes in ice thermal and interior state etc, so that abrupt changes in ice strength properties may be observed from spring (or winter ?) time. Conclusion - Stages of Melt and "Strength Index" are different parameters. B. The stages of melting up to now were or are more or less widely used in ice navigation as an additional empirical coefficient to diminish either "mean ice thickness" or increase "cruise speed" and are easily recorded (but only during manual observations). "Strength Index" looks more easier to record and on much more widely scale instrumentally, but - Is it understandable and easy to incorporate into "ice navigation formulae" ? Conclusion - Stages of Melt and "Strength Index" both may be used for accounting ice strength for the purposes of ice navigation as different parameters. C. Summarizing, the right word for the present WMO Nomenclature definition of ice melting is rather not “inadequate” but incomplete. Proper discussions at IICWG and within WMO/JCOMM expert Team on Sea Ice will led to elaboration of proper extensions and amendments for WMO technical documents. Conclusion - after collaborative work at IICWG and JCOMM Expert Team on SI proper amendments will be done for WMO Sea Ice Nomenclature.