Figure 8.1. Surface currents in the Arctic. Based on AMAP (1998) (THIS WILL BE REPLACED WITH A NEW FIGURE)

Transcription

1 Figure 8.1. Surface currents in the Arctic. Based on AMAP (1998) (THIS WILL BE REPLACED WITH A NEW FIGURE)

2 Figure 8.2.Arctic total sea ice cover and its two components, multi-year ice and first-year ice, as derived from satellite microwave sensors data in winter. The multi-year ice also represents the minimum ice extent in summer (Johannessen and Miles, 2000).

3 Figure 8.3. Ice drift patterns for years with a) low AO - index (anticyclonic conditions) and b) high AO + index (cyclonic conditions) (after Maslowski et al. 2000, Polyakov and Johnson 2000, Rigor et al. 2002). The small arrows show the detailed ice drift trajectories based on an analysis of sea level pressure (Rigor et al. 2002). The large arrows show the general ice drift patterns.

4 Figure 8.4. Two types of processes create unique currents systems and conditions in the Marine Arctic. The input of freshwater, its outflow to the Atlantic, and the en-route entrainment of ambient water creates an estuarine type of circulation in the Marine Arctic. In addition to this horizontal circulation system, thermohaline ventilation creates a vertical circulation system. Both of these are sensitive to climate change. G-S Ridge = Greenland-Scotland Ridge FIGURE 8.5. Schematic view of the freshwater budget of the Arctic Ocean. Low salinity waters are added to the surface and halocline layers of the Arctic Ocean via precipitation and runoff, Pacific inflow via the Bering Strait and the sea ice distillation process. Low salinity waters and sea ice are subsequently advected through Fram Strait and the Canadian Archipelago into the convective regions of the North Atlantic.

5 Figure 8.6. Three of the ventilation processes that occur in the Arctic Mediterranean. Surface outflows: Canadian Archipelago & East Greenland Current 1Sv 1Sv 3.5Sv From the Bering Strait 3.5Sv I F S 3Sv Denmark Strait Overflow Iceland- Scotland Overflow 3Sv 3Sv Figure 8.7. T he Arctic Mediterranean has four current branches that import water in the upper layers, three from the Atlantic (I Iclandic Branch, F Faroe Branch and S Shetland Branch) and one from the Pacific. The outflow occurs partly at depth through the overfl ows and partly as surface (or upper-layer) outflow through the Canadian Archipelago and the East Greenland Current. The numbers indicate volume flux in Sverdrup (10 6 m 3 /s) rounded to half-integer values and are based on observations except for the surface outflow which is adjusted to balance. Based on Hansen and Østerhus (2000).

6 Kola Annual Mean Temperatures ( C) 5.0 Temperature ( C) Figure 8.8 Annual and 5-year running means of the annual mean temperatures from the Kola Section. Figure 8.9. Hovmöller diagram indicating the observed time latitude v ariability of surface air temperature (SAT) anomalies north of 30 N, (Johannessen et al. in press)

7 Temperature Anomaly Kola Stn Fig The 5-year averages of temperatures from the Barents Sea (Kola Section off northwestern Russia, m mean) and the Labrador Sea (Station 27 on the western Grand Bank off eastern Canada, near bottom at 175 m). Temperatures are expressed as anomalies, i.e. differences from their means. FIGURE 8.11: Maps of sea ice concentration based on the NOAA AVHRR ice analysis comparing (a) climatology of ice conditions in summer (September; ) and (b) conditions in September Note substantial changes in ice conditions in the Canada Basin north of the Chukchi Sea, and in Fram Strait and north of Svalbard extant in 2002 compared to the past 25 years.

8 Marginal ice zone Area mill km CGC CSM ECH GFD HAD Year Figure Development on the marginal ic e zone compare with today. The figure is based on the values given in Tables 8.2 and 8.3. CGC (Canadian Center for Climate modeling and analysis), CSM (Community Climate System Mode, NCAR, USA), ECH (ECMWF-Max Planck Institute, Hamburg, Germany) and HAD (Hadley Centre, U:K. - model version 3)

9 Figure 8.13: Schematic diagram depicting the annual pattern of incoming solar radiation (top), wind speed (middle) and the incremental changes in incoming solar radiation and wind energy to the water column from supposed earlier break -up and delayed freeze-up. An earlier break-up will allow a disproportion amount of solar energy into the water column, while delayed freeze-up will expose the water column to autumn storms.

10 Figure 8.14: Evolution of the temperature (SST) and sea-ice field in the BCM CMIP2 integration. Left column shows the March SST and sea ice distribution around the years 2020, 2050, and 2075, and right column changes from year 2000 to 2020, 2050 and 2075 respectively.(furevik et al. 2002)

11 Figure 8.15 Infrared satellite image showing surface temperature between Iceland and Scotland on the 18 th of May Dark areas are warm, light areas are cold, except where there is cloud cover. The Subarctic Front (in this region also called the Iceland-Faroe Front) separates Atlantic and Arctic water masses. Figure 8.16 The red curve on the time series plot shows the (5-year running mean) depth of the 28.0 density surface (γ θ = 28.0 kg m -3 ) at Ocean Weather Ship M (OWS-M on map). This surface can be considered the upper limit of the dense overflow water and its height (H ) above the sill-level of the Faroe Bank Channel (FBC on map) has been interpreted as an indicator for overflow intensity. The deepening trend of the density surface would then imply a decreasing overflow intensity through this channel (Hansen et al., 2001).

12 Figure 8.17 Benthic faunal biomass in the northern regions of the Bering, Chukchi, East Siberian and Beaufort Seas (from Dunton et al. 2002).

13 Figure 8.18 Circumpolar distribution of capelin (Mallotus villosus)

14 Figure Distribution of polar cod (from Ponomarenko, 1968) Figure Walrus (Odobenus rosmarus ) routinely use sea ice as a haul-out platform in shallow areas where they feed on benthic fauna. (Photo: Kit & Christian, NPI)

15 Climate Climate Ice conditions temperature wind Cod Temperature Ice extent temperature ice coverage Capelin Herring temperature Zooplankton temperature advection wind clouldiness ice conditions Phytoplankton Figure 8.21 Simplified illustration on how different climate parameters may impact on the marine food chain, both directly and indirectly (Modified after Stenset h et al. 2002) Figure The relationship between the timing of the ice retreat and the spring bloom for the Bering Sea. (Hunt et al. 2002)

16 Figure Modelled primary production (upper panel) and wind-speed in Atlantic Water of the Barents Sea, summer 1998 (lower panel). Wind data and the hind-cast model are courtesy of the Norwegian Meteorological Institute; production model, D. Slagstad) Deleted: (w Deleted:, Deleted:, the

17 Figure Long-term changes in the abundance of Calanus finmarchicus in CPR surveys REF Figure 8.25 Long -term changes in the abundance of Calanus glacialis in CPR surveys

18 Figure The position of biogeographic boundary in the Barents Sea in 20 th century: I maximal western penetration of arctic species in cold periods; II line of 50% average relation between boreal and arctic species; III maximal eastern penetration of boreal species in warm periods; IV transitional zone. 16 4,3 SSB (mill. tons) ,1 3,9 3,7 t o C 0 3, Year Figure Relation between temperature and herring spawning stock (Toresen and Østvedt 2000)

19 Figure 8.28 Match/mismatch of primary production over the shelf, slope and basin Figure 8.29 Ringed seals are dependent on the sea ice for birthing, resting, moulting and some of their foraging activities. They are the only Arctic seal species that can create and maintain holes in thick sea ice and hence their distribution extends further north than all other pinnipeds. This ringed seal pup is outfitted with a radiotransmitter that was deployed as part of a haul-out behaviour study in Svalbard, spring (Photo: Kit & Christian, NPI)

20 Figure Output of a mathematical simulation model (Kuhn et al. 2000) illustrating the relative effects of selected variables on UV-induced mortality in Calanus finmarchicus embryos. (A -B) Clear vs. cloudy sky. When spectral irradiance is plotted on a log scale (as on the left Y-axis of panel A), the difference between clear and cloudy skies appears small. However, when plotted as a percent (as on the right Y-axis), the magnitude of the difference in irradiance becomes clearer. (C-D) Clear vs. opaque water column. (E-F) 50% thinning of ozone vs. ambient ozone. This graphic illustrates that water column transparency is single most important determinant of UV exposure far more important than is ozone layer depletion. (Modified from Browman et al. 2000).

21 Figure (A) Dissolved organic carbon (DOC) vs. diffuse attenuation coefficient (K d ) at 305 nm from field measurements in the estuary and Gulf of St. Lawrence, Canada. The straight line is the regression, the curved lines are the 95% confidence intervals. (B) K d at 305 nm vs. modelled survival of Calanus finmarchicus embryos exposed to UV radiation in a mixed water column. (C) K d vs. modelled survival of Atlantic cod (Gadus morhua) embryos exposed to UV radiation in a mixed water column. This graphic illustrates the level of protection from UV damage provided by the organic matter content of the water column. (Modified from Browman 2002).

22 Figure 8.32 Profiles of the fugacity (partial pressure corrected for the fact that the gas is not ideal) of CO 2 (f CO 2 µatm) in the Canada Basin (CB) and Eurasian Basin (EB). Data lying to the left of the dotted line are under -saturated and to the right are over -saturated. Note below 50 m in the Canada Basin waters are oversaturated due to advection of Bering Sea Winter Water that have high carbon dioxide concentrations.