Arctic Freshwater Flux and Change

Transcription

1 Arctic Freshwater Flux and Change Daqing Yang, Doug Kane, Sveta Berezovskaya Water and Environment Research Center, Univ. of Alaska Fairbanks Main Topics Large Arctic River Streamflow Regime and Change - Review of recent analyses/results Remote Sensing Snowcover Hydrology - Evaluation of RS snow data Snow Cover Change over Northern Eurasia - Review of recent analyses of in-situ snow data Summary of Major Challenges - Gaps in arctic hydrology research

2 Large Arctic rivers & their annual discharge to the Arctic Ocean/marginal seas 5% 9% 15% 17% 11% Table 1: Physical characteristics for the five major rivers of the Arctic. River Name Drainage Area River Length Annual Discharge Mean Annual Temperature Mean Yearly Precipitation Snowfall Percent Total Res. Capacity (1, Km 2 ) (Km) (Km 3 ) ( C) (mm) (%) Km3 / # dam Ob 2,99 4, / 5 Yenisei 2,58 3, / 12 Lena 2,49 3, / 2 Yukon 1,79 3, / Mackenzie 85 5, / 2

3 High Latitude Temperature Changes,

4 Water Budget and Change (P mean + ΔP) = (R mean + ΔR) + (E mean + ΔE) ± (S mean + ΔS) P precipitation, R- runoff, E evaporation, S storage Positive ΔP, ΔR, ΔE --> intensification of water cycle? FWI Science Questions Is the Arctic Freshwater Cycle Intensifying? If So, Why? What are the Implications?

5 Yearly, Monthly and Daily Streamflow Regime and Change Document discharge change

6 The Big Story Total annual discharge from the 6 largest Eurasian arctic rivers increased by about 2. km 3 /yr during (Peterson et al., Science, 22). Cold season (Oct-Apr) discharge increased by about 25-9% over past decades (Yang et al., JGR, 22; Serreze et al., JGR, 22; Ye at al., WRR, 23). What caused discharge changes???

7 Large Siberian rivers and dam locations A Reservoir J I A N M L K H G F E D C B Ob River: R / P = 134/47 =.29 Permafrost % = 7% Lena River: R / P = 216/39 =.55 Permafrost % = 9%

8 Precipitation vs. Runoff Trends over Largest Siberian Rivers (Berezovskaya, Yang & Kane, GRL, 24) precipitation and runoff anom alies Ob basin.2 Yenisei basin.2 Lena basin NCEP NCEP NCEP UDel -.2 UDel -.2 UDel.2.2 CRU -.2 CRU -.2 CRU Runoff -.2 Runoff -.2 Runoff yr yr

9 Mean Gauge-Measured (Pm) and Bias-Corrected (Pc) Precipitation, and Correction Factor (CF) for January Yang et al., 25, GRL Pm (mm) Pc (mm) CF a) Pm (mm) b) Pc (mm) c) CF Total 4827 stations located north of 45N, with data records longer-than 15 years during Similar Pm and Pc patterns corrections did not significantly change the spatial distribution. CF pattern is different from the Pm and Pc patterns, very high CF along the coasts of the Arctic Ocean.

10 Monthly basin temp climatology (top) and Temperature (c) Ob Yenisei Lena Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec trend (bottom), Ob Yenisei Lena T trends (c) 2 1 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec -1-2

11 Monthly basin precip climatology (top) and trend (bottom), Precip (mm Ob Yenisei Lena Month P trend (mm 1 5 Ob Yenisei Lena Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

12 12, Monthly flow regime and change: 1, 8, 6, 4, 2, Ice cover Ice Lena river, Russian Arctic rivers (Yang et al. 22, 23) Monthly discharge (m3/s) 12, 1, 8, 6, 4, 2, Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Ice cover Ice Jan Feb Mar Apr May Jun Jul A ug S ep Oct Nov Dec Yenisei river, , A Reservoir K N M L H G J I FE D CB A 1, 8, 6, 4, 2, Ice cover Ice Ob river, Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

13 N. America Arctic rivers Mackenzie R., Yukon R., Monthly discharge (m3/s) 3, 25, 2, 15, 1, 5, 3, 25, 2, 15, 1, Ice cover Ice Ice cover Ice 5, Month

14 12, Daily discharge (m3/s 1, 8, 6, 4, 2, Lena Comparisons Daily discharge (m3/s 14, 12, 1, 8, 6, 4, 2, Yenisei of long-term mean daily discharge Daily discharge (m3/s 4, 35, 3, 25, 2, 15, 1, 5, Ob (m3/s) Julian day

15 Daily Flow Variation, Lena Basin Outlet, max

16 Daily Flow Variation, Yenisei Basin Outlet, , 199 max 16, 14, 12, 1, 1967 min 8, 6, 4, 2, Julian day Daily flow (m3/s)

17 Daily Flow Variation, Ob Basin Outlet,

18 Standard Deviation of Daily Flow, Q standard deviation (m3/s)

19

20 Discharge Records and Trends,

21 Daily Flow Regime and Change

22 White et al., 27 Discharge from the large Eurasian rivers increased (Peterson et al., 22). Discharge in NA arctic rivers did not change much (Woo et al., 2x; Dery et al., 25). Discharge from rivers in HJU regions decreased. Why the trends are so different among the regions? What caused discharge changes in the Arctic???

23 Remote Sensing (RS) Snow Cover Hydrology Evaluation of RS snow data, SCE and SWE Basin/region winter snow mass balance SWE = Snowfall Sublimation Basin spring water budget Runoff = SWE + Precip. Evaporation Storage

24 NOAA monthly snowcover extent / Rutgers Univ. Sept Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug

25 Basin weekly snowcover extent (km 2 ) & percent (%), ,5, 3,, 2,5, 2,, 1,5, 1,, 5, a) Mean weekly basin snowcover extent, Ob Yenisei Lena Snowcover extent (Km2) b) Mean weekly basin snowcover percent, % 9% 8% 7% 6% 5% 4% 3% 2% 1% % Ob R Yenisei R Lena R NOAA Snowcover Grid Interpretation Snowcover percent (%)

26 Lena basin weekly snowcover variations 2,5, Lena basin snowcover extent, ,, 1,5, 1,, 5, min mean max ,5, 2,, 1,5, 1,, Snowcover extent (Km2) 5, 17th 19th 21th 23th 25th 27th 29th 31th 33th 35th 37th 39th 41th Weeks

27 Weekly mean basin snowcover & discharge over Siberian large watersheds, Weekly snowcover extent (Km2) 3,5, 3,, 2,5, 2,, 1,5, 1,, 5, 3,, 2,5, 2,, 1,5, 1,, 5, 2,5, a) Ob basin snowcover discharge b) Yenisei Basin Week 4, 35, 3, 25, 2, 15, 1, 5, 1, 9, 8, 7, 6, 5, 4, 3, 2, 1, 1, 2,, 1,5, c) Lena Bain 9, 8, 7, 6, 5, 1,, 4, 3, 5, 2, 1, Weekly discharge (m3/s)

28 Weekly relation of discharge vs. snowcover extent Weekly discharge (m3/s) 25, 2, 15, 1, 5, 18, 16, 14, 12, 1, 8, 6, 4, 2, y = Ln(x) R 2 =.4645 y = Ln(x) R 2 =.3245 week 17 week18 week 19 Log. (week18) Log. (week 19) Log. (week 17) y = Ln(x) R 2 = , 1,, 1,5, 2,, 2,5, 3,, y = Ln(x) R 2 =.21 week 2 week 22 Log. (week 2) Log. (week 22) y = -3744Ln(x) R 2 =.245 5, 1,, 1,5, 2,, 2,5, 3,, Ob River, Weeks Yenisei River, Weeks , 18, 16, 14, 12, 1, 8, 6, 4, 2, y = Ln(x) R 2 =.3717 week 21 week 22 Log. (week 22) Log. (week 21) y = -2421Ln(x) R 2 =.451 Lena River, Weeks , 1,, 1,5, 2,, 2,5, Weekly snowcover extent (km2)

29 Ob Basin Yenise Basin Lena Basin Snow Water 1979,Q Equivalent =44,643m 3 /s peak (SWE) 199,Q Information =157,286m 3 /s peak 1989,Q =177,429m 3 /s peak ,Q =26,286m 3 /s peak ,Q =64,771m 3 /s 2 peak ,Q =84,457m 3 /s peak Discharge (1 m 3 /s) Discharge (1 m 3 /s) Discharge (1 m 3 /s) Modified Weeks Modified Weeks Modified Weeks Discharge (1 m 3 /s) Yukon Basin 1985,Q peak =3,299m 3 /s 1978,Q peak =12,969m 3 /s Modified Weeks Discharge (1 m 3 /s) Mackenzie Basin 1992,Q peak =33,343m 3 /s 1995,Q peak =15,86m 3 /s Modified Weeks SWE ~ Discharge Basin extreme (weekly-mean) discharge (m3/s). Data source: UNH/SHI

30 14 2,SWE = 136.4mm Snow Water Equivalent (SWE) Information max ,SWE = 114.2mm max Lena basin has the ,SWE = 75.2mm max ,SWE = 97.8mm max 1998,SWE = 76.2mm max ,SWE = 19.2mm highest max winter snow pack, and Yenisei basin has the lowest. Weekly mean SWE (mm) Weekly mean SWE (mm) 2 Ob.5mm Modified Weeks Yukon 1998,SWE max = 124.7mm 1991,SWE max = 8.9mm.5mm Modified Weeks Weekly mean SWE (mm) Weekly mean SWE (mm) 14 2 Yenise.5mm Modified Weeks Mackenzie 21,SWE max = 12.6mm 1993,SWE max = 82.1mm.5mm Modified Weeks Weekly mean SWE (mm) 14 2 Lena.5mm 2. The snow pack Modified Weeks accumulate to the highest in winter, week Basin SWE interannual variation 2. For study Extreme convenience, (SSM/I) snowcover when water when equivalent SWE (SWE, <.5mm, mm), the basin is considered Data source: empty. NSIDC/UNH

31 Average of snow water equivalent (SWE), Prepared by A.N.Krenke, L.M. Kitaev

32 Basin SWE (mm) vs. weekly discharge (m3/s), Lena R., The SWE and Dicharge in Lena Basin, 1988~ SWE (mm) Discharge (1 m 3 /s) Weeks Streamflow = SWE ET?

33 Basin SWE vs. winter precip (mm), Lena R., SWE and AP (mm) SWE AP Weeks SWE = Snowfall Sublimation?

34 Basin SWE vs. winter precip (mm), Ob R., SWE and AP (mm) SWE AP Weeks

35 Snow Cover Change over Northern Eurasia Groisman, P. Ya., R. W. Knight, V. N. Razuvaev, O. N. Bulygina, and T. R. Karl, 26: State of the ground rarely used characteristic of snow cover and frozen land: Climatology and changes during the past 65 years over Northern Eurasia., J. Climate, Vol.19, 19, pp

36 Long-term mean annual number of days with snow on the ground < > 27

37 Mean snow depth for permanent snowcover period,

38 Linear trend in number of days with more than 5% snow cover for

39 Linear trend in number of days with snow cover exceeding 1cm for

40 Linear trend in number of days with snow cover exceeding 2cm during

41 Major Challenges in Arctic Hydrology Research Basin/regional water balance Quality and consistency of precipitation, snowcover (SWE), river discharge data Lack of regional/basin ET data for water budget analyses Uncertainties in storage (ground ice, glaciers, lake/reservoir storage) amount and change Hydrologic change detection and attribution Quantify and separate hydrologic response to climate change and human influence Time Scale: yearly, monthly, daily, and extreme events Spatial scale: continent, river basin, and sub-basin Gaps in arctic hydrology research Pan arctic in-situ snow data sets (snow depth, SWE and density) Validation of RS precipitation and snow data/products