SEASONAL OUTLOOK SEA ICE CONDITIONS FOR BAFFIN BAY, DAVIS STRAIT, LABRADOR SEA AND THE SOUTHWEST GREENLAND WATERS SUMMER 2002 NATIONAL / NAVAL ICE CENTER Historically the Baffin Bay melt does not begin until June, although the first signs of the North Open Water are observed in May. During the beginning of the melt, the western boundary of the pack ice begins to recede eastward, meeting the north open water. A broad flaw lead forms along the Greenland coast and gradually moves northward to Melville Bay. The pack ice begins receding, leaving an ice bridge across Baffin Bay (from NW Greenland to Central Baffin Island). This ice bridge will typically break sometime between the last half of July and the third week of August. The remaining ice will be composed of rotten floes that are rapidly deteriorating, and disappear completely by mid-September. The two main objectives of the Eastern Seasonal Outlook are to forecast the thinning of the ice bridge for planning escorted shipping operations, and the breaking of the ice bridge for planning for unescorted operations. Overall, summer melt conditions throughout the route across the Davis Strait and Baffin Bay are expected to be ahead of schedule for the 2002 shipping season. Table 1 provides the forecasted opening dates for the summer of 2002 compared to the normal opening dates for the transit to Thule, Greenland. Table 1 Forecast and Normal Opening Dates Thule, Greenland PORT FORECAST NORMAL FORECAST NORMAL ESCORTED ESCORTED UNESCORTED UNESCORTED OPENING OPENING OPENING OPENING DATE DATE DATE DATE Thule July 01 July 20 July 11 August 5 Escorted: Concentrations of ice encountered on the transit to Thule will be 7/10s or less and any fast ice will be in a weakened state. Unescorted: Concentrations of ice encountered on the transit to Thule will be 1/10 or less. Freezing Degree Day (FDD) Accumulations and Ice Thickness (Table 2) are shown for the 2001-2002 winter season and historical Maximum, Minimum, and Mean data for selected locations in the Baffin Bay / Davis Strait / Labrador Sea area. (See Figure 1 for port locations). Ice thickness values are slightly thinner than the mean climatological thickness in all cases for mid-May 2002 with the exception of Cape Dyer and Sondrestrom, which were both slightly above the mean. The Freezing Degree Day (FDD) values for the stations along the western shore of Greenland (Thule, Upernavik) were both below normal for mid-May 2002. The two stations reporting on the western shore of Baffin Bay and Davis Strait (Cape Dyer, Frobisher Bay) both observed above normal FDD values for mid-May 2002. Table 2 Current and Climatological Freezing Degree Days / Theoretical Thickness (Freezing Degree Days - Degrees C) (Theoretical Thickness - Centimeters) LOCATION MAXIMUM MINIMUM MEAN 15 MAY 02 FDD / THK FDD / THK FDD / THK FDD / THK Thule 5093 / 178 3721 / 142 4496 / 168 4239 / 161 Upernavik 3654 / 149 2207 / 75 3043 / 134 2758 / 126 Sondrestrom 4010 / 146 1915 / 26 2927 / 108 (3157 / 136)^ Cape Dyer 4607 / 71 3204 / 137 3927 / 155 4006 / 156 Frobisher Bay 4660 / 171 3182 / 122 3866 / 155 3917 / 154 Angmagssalik 1793 / 94 949 / 41 1260 / 81 0 / 0* Resolution Is. 3766 / 152 2066 / 105 2927 / 132 0 / 0* * Values reset before 15 May 2002. ^ Values at Sondrestrom on 01 May 2002, before they reset. Table 3 lists the distance in nautical miles from select ports to the nearest ice edge on the 29th of April 2002, verses the mean distance for the 1st of May. As can be seen from Table 3, the distance to the ice edge is lower than normal for Upernavik & Thule, near normal for Cape Dyer, and greater than normal for Frobisher Bay, Angmagssalik and Resolution Island. Table 3 Distance From Selected ports to the ice edge in nautical miles. PORT MEAN (May 1) PRESENT (Apr 29, 2002) Thule 540 455 Upernavik 210 155 Cape Dyer 130 130 Frobisher Bay 240 285 Angmagssalik 60 70 Resolution Is. 80 135 Figure 2 indicates the climatological maximum, mean and minimum positions of the ice edge for May 15th. Figure 3(a-d) depicts the actual ice conditions present for the week of 13-17 May, 2002. The ice extent in the Grand Banks, Labrador Sea and Baffin Bay lies near a climatological mean. The ice extent in the Davis Strait was below a climatological mean. By the week of 20-24 May, the waters in the vicinity of Disko Island had become open water. Several factors were considered during the preparation of the outlook. Their description and weight in the outlook are discussed in the following paragraphs. Values plotted on standard ice thickness curves for Thule and Upernavik showed values thinner than the mean climatological ice thickness curves for the early winter season, but trending closer to the mean by the beginning of May. Freezing Degree Days (FDD) data for Thule and Upernavik were below normal for the winter of 2001-02, leading to thinner than normal ice thickness. Cape Dyer and Frobisher Bay were above normal for the winter of 2001- 02, leading to thicker than normal ice thickness. Values for freezing degree days accumulation and ice thickness are compared with past years and shown in Table 2. As noted in Table 3 the distances to the ice edge are near to slightly above the mean for all stations, with the exception of Thule & Upernavik on the western Greenland coast. Next, we compared the ice edge and inner pack concentrations from the week of May 20- 24 to our climatological database of archived charts to find an analog year. After comparing the ice edge and re-occurring polynyas from May of this year to May of years past, 1988, 1985 and 1987 were chosen as the best analogs for the current ice conditions. Unescorted transit times for these three analog years were the 13 July, 09 July, and 05 August, respectively. These dates are all earlier than normal to near normal for the appearance of unescorted transit conditions. Figure 4 shows mean climatological conditions for July 15. In the third week of May, ice forecasters from the National Ice Center (NIC) met with ice forecasters from the Canadian Ice Service (CIS) to compare our findings. The East Seasonal Outlook produced by CIS is of a larger scope than what is presented here. However, the information that goes into their forecast is similar to the information used by the NIC. The CIS Seasonal Outlooks can be accessed on the CIS homepage at http://ice-glaces.ec.gc.ca Due to the combination of factors listed above, the unescorted opening of the ice route for the transit to Thule, Greenland is forecasted to be earlier than normal for the summer of 2002.