Chapter PRECIPITATION AND EVAPOTRANSPIRATION

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1 Chapter PRECIPITATION AND EVAPOTRANSPIRATION Fig Mean monthly precipitation (P), precipitation minus evapotranspiration (P-E) and evapotranspiration (E) for the four major Arctic watersheds, based on data from 1960 through Units are mm. E was calculated as a residual from P and P-E. Seasonal cycles correspond to water year. [From Serreze et al., 2003].

2 Fig Percentage changes of P (upper panel), E middle panel) and P-E (lower panel) projected for by the ACIA-designated climate models. Projected changes are shown for the Arctic Ocean and five major Arctic river basins. Solid circles are five-model means; vertical line segments denote the ranges of the five model projections.

3 Fig March and September mean ice concentration maps from SSMI, [From C. Parkinson, NASA Goddard Space Flight Center].

5.2 SEA ICE Fig. 5.2.2 Daily Arctic sea ice extents (upper) and their anomalies (lower) from 1972 through 2000.

4 5.2 SEA ICE Fig Daily Arctic sea ice extents (upper) and their anomalies (lower) from 1972 through A linear trend line is indicated on the daily extents and a 365-day running mean is included on the daily anomalies [from Cavalieri et al., 2003].

5 Fig Annual values of the Koch Index of sea ice along the coasts of Iceland. Fig Historical record of April ice extent (2-year running means) in the Nordic Seas (NS) and in their eastern (E) and western (W) subregions. [From T. Vinje (2001), J. Climate, 14, p. 256].

6 Fig Averages ice concentrations (color-coded) at time of summer ice minimum for two 11-year periods: (a) 1979 to 1989 and (b) 1990 to (c) is difference field, (b) minus (a), depicting loss of ice from to [From Comiso, 2002, Fig. 2].

Fig. 5.2.6 Time series of 21st-century total N.

7 Fig Time series of 21st-century total N. Hemisphere ice extent projected by five global climate models for March (left panels) and September (right panels). Upper panels show raw model output; lower panels are adjusted for biases in simulated presentday sea ice.

8 Fig Five-model composite maps of sea ice coverage for September of (a) 2020, (b) 2050, (c) Fig Same as Fig , but for March.

5.3 SNOW COVER Fig. 5.3.1 Frequency of snow cover on the land areas of the Northern Hemisphere during winter (December), early and late spring transition months (March and May), and an autumn transition month (October).

9 5.3 SNOW COVER Fig Frequency of snow cover on the land areas of the Northern Hemisphere during winter (December), early and late spring transition months (March and May), and an autumn transition month (October). In all panels, the 50% contour (in the green zone) represents the approximate climatological mean position of the snow boundary. [Figure courtesy of David Robinson, Snow Data Resource Center, Rutgers Univ. Climate Lab].

10 Fig Twelve-month running mean of snow extent in the Northern Hemisphere from 1972 to 2003 for North America with Greenland (red), Eurasia (blue) and entire hemisphere (black). [From David Robinson, Rutgers University]. Fig Eleven year running mean extent of snow cover for (a) North America during Nov.-Dec. (red), Jan.-Feb. (blue) and Mar.-Apr. (green); (b) Eurasia during Oct. (red) and Mar.-Apr. (green). [Data from Ross Brown, Meteorological Service of Canada].

11 Fig Distribution of snow cover during the time slice for the months of March, May, October and December, using as the measure of coverage the number of models (out of five models) in which snow is present at least half the time. Blue, green, orange red and gray denote presence of snow in 1, 2, 3, 4, and 5 models, respectively

5.4 GLACIERS AND ICE SHEETS Fig. 5.4.1. Map of the Arctic showing the location of the glaciers where mass balance data are available.

12 5.4 GLACIERS AND ICE SHEETS Fig Map of the Arctic showing the location of the glaciers where mass balance data are available. Wo - Wolverine Glacier, Gu - Gulkana Glacier,Mc- Mc Call, MSI - Melville S. Ice Cap,Ba - Baby glacier, Me - Meighen Ice Cap, DI - Devon Ice Cap,Dr Drambui, Ho - Hofsjökull, Tu- Tungnarjökull, Br - Austre Brøggerbreen, Ko - Kongsvegen, En - Engabreen, Sg - Storglaciären, IG - Igan, Ob - Obruchev, Va - Vavilov. Fig Mass balance sensitivity to temperature change (red) and potential sea-level rise (blue) for the Arctic regions in Table (GIS = Greenland Ice Sheet).?Bm/?T is the change in mass balance (meters water equivalent) per K of temperature change. SLR is Sea Level Rise (mm per K per year). Red bars represent mass loss and blue bars mass gain.

13 Fig Accumulated annual volume changes of ice caps and glaciers in the American Arctic (open circles), the Russian Arctic (open squares), the Eurasian Arctic (filled circles), and the entire Arctic (crosses). Figure provided by M. Dyurgerov, INSTAAR, Univ. of Colorado, Figure Time series ( ) of maximum summer melt extent over Greenland (left), and examples of the melt extent during 1992 and 2002 (right). [Figures provided by K. Steffen, CIRES/Univ. of Colorado].

14 Fig Contribution to sea-level change from arctic glaciers calculated from model output. Fig Contribution to sea-level change for various regions, calculated from ECH model output - temperature effect only.

5.5 PERMAFROST 5.5(1) Terrestrial permafrost Fig. 5.5.1 Permafrost distribution in the Northern Hemisphere.

15 5.5 PERMAFROST 5.5(1) Terrestrial permafrost Fig Permafrost distribution in the Northern Hemisphere. Colored circles are locations of boreholes. [From Romanovsky et al., 2002, Fig. 1].

Fig. 5.5.2 Mean annual ground temperatures at Fairbanks (Bonanza Creek), Alaska, from 1930 to 2000.

16 Fig Mean annual ground temperatures at Fairbanks (Bonanza Creek), Alaska, from 1930 to Temperatures are shown for depths of 0.09 m (red), 0.30 m (green), 0.50 m (light blue) and 1.0 m (dark blue). [From V. Romanovsky ]

Fig. 5.5.3. Summary of circum-arctic changes of distribution of permafrost (sporadic/discontinuous and continuous) based on forcing from five different global climate models.

17 Fig Summary of circum-arctic changes of distribution of permafrost (sporadic/discontinuous and continuous) based on forcing from five different global climate models. As summarized in color-coding legend, blue and purple denote areas of unchanged sporadic and continuous permafrost, respectively. [Adapted from Anisimov and Belolutskaia, 2004a].

18 Fig Changes in active layer depth in 2050, relative to present-day simulations, based on forcing from five different global climate models. Changes range from 0-20% (beige )to more than 50% (blue). [Anisimov et al, 1997, updated].

19 Fig Temperature changes (ºC) between 2000 and 2100 over northern Alaska forced by B2 scenario output of CGC, CSM, GFD and HAD models. A reference case using forcing from the HAD- Version-2 model is shown at top. [From Sazonova et al., 2004].

20 Fig Increase in active-layer thickness (m) between 2000 and 2100 over northern Alaska forced by B2 scenario output of CGC, CSM, GFD and HAD models. A reference case using forcing from the HAD2 model is shown at top. [From Sazonova et al., 2004].

21 Fig Subsea permafrost distribution in the Arctic (based on Brown et al 1998) is confined largely to wide continental shelf areas which were unglaciated during the Holocene. Narrow zones of coastal permafrost are probably present along most Arctic coasts.

9 The maximum thickness of landfast ice developed in the coastal areas at 4

22 Fig The coastal and offshore permafrost zones [after Osterkamp, 2001]. Fig The maximum thickness of landfast ice developed in the coastal areas at 4 locations in the Canadian Arctic is highly variable form one year to the next (left panel). Smoothed variations in thickness suggest some similarities in behavior (right panel).

5.6 RIVER AND LAKE ICE Fig. 5.6.1 Ten-year running means of freeze-up (top) and break-up (bottom) dates of selected lakes and rivers in Northern Hemisphere: Mackenzie River (Canada), Red River

23 5.6 RIVER AND LAKE ICE Fig Ten-year running means of freeze-up (top) and break-up (bottom) dates of selected lakes and rivers in Northern Hemisphere: Mackenzie River (Canada), Red River (Canada), Kallavesi Lake (Finland), Lake Mendota (U.S.), Lake Suwa (Japan), Angara River (eastern Russia), Lake Baikal (eastern Russia), Grand Traverse Bay (U.S.). [From Magnuson et al., 2001, Science, 289, p. 1744].

24 Fig Time series of break-up date of Tanana River at Nenana, AK. [Data from National Snow and Ice Data Center, Boulder, CO; plot by W. Chapman].

5.7 FRESHWATER DISCHARGE Fig. 5.7.1 The Arctic "half hemisphere" showing oceans, shelf-seas with

25 5.7 FRESHWATER DISCHARGE Fig The Arctic "half hemisphere" showing oceans, shelf-seas with catchment areas and river network for the Pan-Arctic. Blue line represents relative river discharge.

26 Fig Time series of the number the river gauges in the pan-arctic drainage basin and data available in total R-ArcticNet, the operational Arctic-RIMS project, and changes in the number of river discharge gauges in North America and Russia. In 1999 the discharge monitoring network had the same number of gauges as in 1960.

27 Fig Dynamics of river discharge to the Arctic Ocean from different parts of the drainage basin for (thin dash line shows annual values, solid line shows 5-year moving average, thick dash line shows linear trend)

28 Fig Ten-year running averages of the Eurasian Arctic river anomaly, winter (Dec.-Mar.) NAO index, and global mean surface air temperature (SAT). "Anomaly" refers to departure from the mean. [From Peterson et al., 2002, Fig. 3].

29 Fig Deviations of (a) spring, (b) summer-fall, (c) winter and (d) annual runoff for as a percentage of mean for each location. Mean is based on entire gauge station history, which is at least 50 years for all plotted locations.

5.8 SEA LEVEL RISE AND COASTAL STABILITY Fig. 5.8.1 Map of the Arctic showing areas (in red) in which elevation is less than 10 meters above mean sea level. Fig. 5.8.2 Coastal stability is a function of sea level, environmental forcing and geological properties of the coastal materials.

Unstable coastal environments are shown in the insets from the Pechora and Laptev Seas (ACD website) and the Beaufort Sea coast.

30 5.8 SEA LEVEL RISE AND COASTAL STABILITY Fig Map of the Arctic showing areas (in red) in which elevation is less than 10 meters above mean sea level. Fig Coastal stability is a function of sea level, environmental forcing and geological properties of the coastal materials. Unlithified Arctic coasts (shown in green) containing variable amounts of ground ice are more susceptible to erosion than lithified coasts (brown) (after Brown et al 1997, IPA map database). Unstable coastal environments are shown in the insets from the Pechora and Laptev Seas (ACD website) and the Beaufort Sea coast. Glacio-isotatic adjustment varies considerably around the Arctic from uplift (black isopleths) in the Canadian Archipelago, Greenland and Norway to subsidence (blue isopleths) along the Beaufort Sea and Siberian coasts (based on Peltier, 2002).

Fig. 5.8.3 Temporal variations in global mean sea level computed from TOPEX/ POSEIDON over the period from December 1992 to July 2002.

31 Fig Temporal variations in global mean sea level computed from TOPEX/ POSEIDON over the period from December 1992 to July Red dots are 10-day averages, blue curve is 60-day smoothed time series. [From Univ. of Colorado Center for Astrodynamics Research,

Fig. 5.8.4 Relative sea level (RSL) affects the stability of any coastal region.

Additional stations from Alaska (NOAA website) show mostly falling sea levels in the Pacific region (probably related to tectonic activity) and a single station from the Canadian Arctic show rising

32 Fig Relative sea level (RSL) affects the stability of any coastal region. RSL is rising (blue dots) at most Arctic stations along the Russian Arctic coast (Proshutinsky et al, 2001; Proshutinsky, in prep). Additional stations from Alaska (NOAA website) show mostly falling sea levels in the Pacific region (probably related to tectonic activity) and a single station from the Canadian Arctic show rising sea level. Sea ice conditions, especially increasing amounts of open water also contribute to increasing coastal instability. The light green area in the Arctic Ocean represents the September ice extent from the HadISST data. Ice is indicated where ice concentrations exceeded 15% in at least half of the Septembers. The pink area is the corresponding ACIA model-projected ice extent (ice present more than 50% of the time in September during The significant increase in the open water extent will likely create more energetic wave and swell conditions at the coast resulting in greater instability Fig Global sea level rise, 1990 to 2100, obtained by the IPCC (2001) from the SRES scenarios. Thermal expansion and land ice changes were calculated using a simple climate model calibrated separately for each of seven atmosphere-ocean global climate models. Contributions from changes in permafrost, the effect of sediment deposition, and the long-term adjustment of the ice sheets to past climate change were added. Each of the six lines is the average of all the models for one of six illustrative SRES scenarios. The region of dark shading shows the range of the seven-model average for all 35 SRES scenarios. The light shading shows the range of the seven models for 35 scenarios. The range delimited by the outermost lines is the range of all models and scenarios with the additional uncertainties due to changes in land ice, permafrost and sediment deposition [From IPCC, 2001, Fig ].

33 Fig Predicted sea level rise based on output from nine global climate models [see IPCC (2001) for description of scenarios used].

The Hydrologic Cycle

The Hydrologic Cycle Monthly precipitation for the central Arctic Ocean based on data from the Russian North Pole manned camps with daily bias adjustments. Raw precipitation totals are shown along with