Wind Characteristics on the NSR

(from Navigational Book 4151; translated from Russian)

Wind direction, speed and persistence have direct influence on navigation. In the presence of sea ice in the area of NSR winds are an important factor affecting ice conditions as ice drifts triggered by winds are common in all the Arctic seas. By their influence on ice drifts, winds can be divided into "pushing-off" and "pushing-to" winds. Pushing-off winds lead to better ice conditions, i.e. they weaken or remove pressure in the closed ice, whereas pushing-to winds cause the opposite. Along practically the whole of the NSR, except for certain isolated areas, unfavorable (pushing-to) winds are these blowing from the north. In the western part of the NSR occurrence rate of the pushing-to winds ranges from 60-70% in June to 33-35% in August. In the eastern part of the NSR (eastern East Siberian Sea and Chukchi Sea) occurrence rate of the pushing-to winds increases towards the end of navigation period. In the central part of the NSR (Laptev Sea) occurrence rate of the pushing-to winds accounts for about 50%.

Occurrence of the pushing-to winds considerably changes from year to year. For instance, in August 1975 it was 39% of the time in the area west of Proliv Vil'kitskogo, but in August 1976 it was 81%. In the area of Novosibirskiye Ostrava occurrence of the pushing-to winds were 20% in August 1979 but in August of 1980 and 1981 it was 64% and 68% of the time, respectively. Pushing-to winds usually are followed by pushing-off winds, or by gentle winds lasting normally for 3 days; sometimes they last for 8 days and for more than 15 days in the areas to the west and east of Proliv Vil'kitskogo and in the vicinity of Novosibirskiye Ostrova. The longest duration of pushing-to winds (32 days) has been observed in the western part of the Laptev Sea and in the area to the west of Proliv Vil'kitskogo.

Occurrence rate of winds with speed up to 12 m/sec (up to 15 m/sec in gusts) is greatest in the northernmost stretches of the NSR, especially at the end of navigation season. In the rest of the NSR winds with speed up to 12 m/sec occur 10-19% of the time. Strong winds normally last for 1- 3 days although they can last up to 6 days in some parts of the NSR.

Gales with wind speed of 20 m/sec or more normally last for one day. The westernmost part of the NSR is the exception, where gales can last for up to 4 days. In the area east of Proliv Vil'kitskogo and to Proliv Longa, duration of gales with wind speed 20 m/sec or more has not exceed 2 days during a navigation period. In the western part of the East Siberian Sea such winds very rarely last for one day.

State hydrographic department of the Ministry of Transport of Russian Federation, 1996, Wind Characteristics on the NSR, .©