Atlantic Ocean-North Africa-Middle East climate linkages through the Holocene

Transcription

1 ACCWW Meeting, LDEO, July 29 Atlantic Ocean-North Africa-Middle East climate linkages through the Holocene Yochanan Kushnir (LDEO) and Mordechai Stein (Geological Survey of Israel) Work inspired by discussions with ACCWW research group: Wally Broecker, Richard Seager, Peter DeMenocal, Joerg Schaeffer, and others.

2 Atlantic Multidecadal Variability 2

3 Atlantic Multidecadal Variability 2

4 Atlantic Multidecadal Variability 2

5 Atlantic Multidecadal Variability 2

6 .1 ATLANTIC MULTIDECADAL SST VARIABILITY LINKING PRECIPITATION VARIABILITY IN THE LEVANT, SAHEL, AND THE AMERICAN WEST.1.1 Atlantic Multidecadal Variability 2

7 Projected change in precipitation IPCC MULTI-MODEL AVERAGE: A1B (28-99) CMIP3(198-99) 3

8 Projected change in precipitation IPCC MULTI-MODEL AVERAGE: A1B (28-99) CMIP3(198-99) 3

9 4

10 Large and significant model-projected drying of the Mediterranean highlights the importance of understanding... 4

11 Large and significant model-projected drying of the Mediterranean highlights the importance of understanding... climate processes that govern Mediterranean precipitation variability on decadal to multi-decadal time scales, for attribution of current changes and for determining the impact of natural vs. anthropogenic climate variability on the regions future 4

12 Large and significant model-projected drying of the Mediterranean highlights the importance of understanding... climate processes that govern Mediterranean precipitation variability on decadal to multi-decadal time scales, for attribution of current changes and for determining the impact of natural vs. anthropogenic climate variability on the regions future The instrumental record alone is too short for addressing these objectives in a robust manner and global models may not capture the detailed regional setting 4

13 Large and significant model-projected drying of the Mediterranean highlights the importance of understanding... climate processes that govern Mediterranean precipitation variability on decadal to multi-decadal time scales, for attribution of current changes and for determining the impact of natural vs. anthropogenic climate variability on the regions future The instrumental record alone is too short for addressing these objectives in a robust manner and global models may not capture the detailed regional setting This calls for reliable hydroclimate proxy record within the region and its surroundings, which can be compared with instrumental obs. to determine the dominant temporal and spatial scales of the variability 4

14 The Holocene Dead Sea Record

15 The Dead Sea Record Mt. Hermon SILL Ein Gedi Ze elim Lake Lisan Jericho SILL The Dead Sea basin drainage Composite based on: Bartov et al. (22), Migowski et al. (26), and Bookman et al. (24) 6

16 The Dead Sea Record 26-24ka Mt. Hermon SILL Ein Gedi Ze elim Lake Lisan Jericho SILL The Dead Sea basin drainage Composite based on: Bartov et al. (22), Migowski et al. (26), and Bookman et al. (24) 6

17 The Dead Sea Record 26-24ka Mt. Hermon SILL Ein Gedi Ze elim Lake Lisan Jericho SILL The Dead Sea basin drainage Composite based on: Bartov et al. (22), Migowski et al. (26), and Bookman et al. (24) 6

18 The Dead Sea Record 26-24ka Mt. Hermon SILL Ein Gedi Ze elim Lake Lisan Jericho SILL The Dead Sea basin drainage Composite based on: Bartov et al. (22), Migowski et al. (26), and Bookman et al. (24) 6

19 The Dead Sea Record 26-24ka Mt. Hermon Lake Lisan mostly below sill SILL Ein Gedi Ze elim Jericho SILL The Dead Sea basin drainage Composite based on: Bartov et al. (22), Migowski et al. (26), and Bookman et al. (24) 6

20 The Dead Sea Record 26-24ka Mt. Hermon Lake Lisan mostly below sill SILL Ein Gedi Ze elim Jericho SILL The Dead Sea basin drainage Composite based on: Bartov et al. (22), Migowski et al. (26), and Bookman et al. (24) 6

21 The Dead Sea Record 26-24ka Mt. Hermon mostly above sill Lake Lisan mostly below sill SILL Ein Gedi Ze elim Jericho SILL The Dead Sea basin drainage Composite based on: Bartov et al. (22), Migowski et al. (26), and Bookman et al. (24) 6

22 DSL-Sahel records: an epochal anti-phase relationship Radiation E.Atlantic N.African lakes Arabian Sea ODP Core 658C Sahara-Sahel Bougdouma L. Abiyata Core 95 Dead Sea Lake Level ) (meters below msl) Age cal. years BP from Liu et al. (27) High Intermediat Dr Low sill level High 7

23 DSL-Sahel records: an epochal anti-phase relationship Radiation E.Atlantic N.African lakes Arabian Sea ODP Core 658C Sahara-Sahel Bougdouma L. Abiyata Core 95 Dead Sea Lake Level ) (meters below msl) Age cal. years BP from Liu et al. (27) High Intermediat Dr Low sill level High 7

24 DSL-Sahel records: an epochal anti-phase relationship Radiation E.Atlantic N.African lakes Arabian Sea ODP Core 658C Sahara-Sahel Bougdouma L. Abiyata Core 95 Dead Sea Lake Level ) (meters below msl) Age cal. years BP from Liu et al. (27) High Intermediat Dr Low sill level High 7

25 DSL-Sahel records: an epochal anti-phase relationship Radiation E.Atlantic N.African lakes Arabian Sea ODP Core 658C Sahara-Sahel Bougdouma L. Abiyata Core 95 Dead Sea Lake Level ) (meters below msl) Age cal. years BP from Liu et al. (27) High Intermediat Dr Low sill level High 7

26 DSL-Sahel records: an epochal anti-phase relationship Radiation E.Atlantic N.African lakes Arabian Sea ODP Core 658C Sahara-Sahel Bougdouma L. Abiyata Core 95 Dead Sea Lake Level ) (meters below msl) Age cal. years BP from Liu et al. (27) High Intermediat Dr Low sill level High 7

27 Holocene Sahel-Levant- Atlantic connection Radiation E.Atlantic N.African lakes ODP Core 658C Sahara-Sahel Dead Sea Lake Level July 65 N ) (meters below msl) (Wm -2 ) Insolation 65 N, July Age cal. years BP 5 1 alkenone PC SST KIM ET AL. (27) EOF alkenone (62%) 15 LIU ET AL. (27) High Intermediat Low sill level High BOOKMAN ET AL. (27) 8 N 6 N 4 N 2 N (1 ) (2 ) (3 ) (4 ) (5 ) (6 ) (7 ) (8 ) +. 8 (9 ) W 6 W 6 E Correlation of Alkenon SST with PC1 8

28 Holocene Sahel-Levant- Atlantic connection Radiation E.Atlantic N.African lakes ODP Core 658C Sahara-Sahel Dead Sea Lake Level July 65 N ) (meters below msl) (Wm -2 ) Insolation 65 N, July Age cal. years BP 5 1 alkenone PC SST KIM ET AL. (27) EOF alkenone (62%) 15 LIU ET AL. (27) High Intermediat Low sill level High BOOKMAN ET AL. (27) 8 N 6 N 4 N 2 N (1 ) (2 ) (3 ) (4 ) (5 ) (6 ) (7 ) (8 ) +. 8 (9 ) W 6 W 6 E Correlation of Alkenon SST with PC1 8

29 Timing of fast (abrupt) changes F. Gasse (25) B-A, YD & some other events exhibit anti-phase behavior but some (more rapid) events are in phase DSL m bmsl 9

30 Timing of fast (abrupt) changes F. Gasse (25) B-A, YD & some other events exhibit anti-phase behavior but some (more rapid) events are in phase DSL m bmsl 9

31 Timing of fast (abrupt) changes F. Gasse (25) B-A, YD & some other events exhibit anti-phase behavior but some (more rapid) events are in phase DSL m bmsl 9

32 The Modern Dead Sea Record: relating DSL to regional precipitation

33 Dead Sea watershed & historical levels Measured lake levels during the first half of the 2th century can be used for calibration against precipitation in the longest recording station(s) within the DS watershed Enzel et al (23) 11

34 DSL vs. Jerusalem ppt 12

35 DSL vs. Jerusalem ppt Enzel et al (23) Area-averaged annual rainfall in the western part of the Dead Sea basin ( mean is 61 mm) and total annual Dead Sea level changes ( ; i.e., prior to major regulation in the drainage basin) recalculated from (Klein and Flohn, 1987). Fitted polynomial equation indicates natural level drop during extremely dry years by 4 5 cm yr1. (during that period the lake also covered its southern basin). 12

36 DSL vs. Jerusalem ppt Nonlinear relationship may be due to decrease in E as salinity increases and/or change in lake surface area and/or reduced runoff Enzel et al (23) Area-averaged annual rainfall in the western part of the Dead Sea basin ( mean is 61 mm) and total annual Dead Sea level changes ( ; i.e., prior to major regulation in the drainage basin) recalculated from (Klein and Flohn, 1987). Fitted polynomial equation indicates natural level drop during extremely dry years by 4 5 cm yr1. (during that period the lake also covered its southern basin). 12

37 Rise & Fall of the DSL 189 s rise = ~6 m dec fall = ~4 m dec fall = ~4 m dec -1 Overall fall 19 to 196 = ~1.2 m dec -1 associated with an overall annual drying of ~5 mm dec -1 '$!!"!""#$%&'()*+,-./&-$"1&'22/& '#!!" '!!!" &!!" %!!" $!!" #!!"!" '(()" '((#" '(&(" '(&%" '(&*" '(&!" '(++" '(+$" '(+'" '(%&" '(%)" '(%#" '()(" '()%" '()*" '()!" '($+" '($$" '($'" '(*&" '(*)" '(*#" '(#(" '(#%" '(#*" '(#!" '('+" '('$" '(''" '(!&" '(!)" '(!#" '&((" '&(%" '&(*" '&(!" '&&+" '&&$" '&&'" '&+&" '&+)" '&+#" '&%(" '&%%" '&%*" '&%!" '&)+" '&)$" '&)'" '&$&" time 13

38 Jerusalem vs. Sahel cm/month !1!2!3!4!5 JJASO!mean Sahel precipitation anomalies 19!27 JERUSALEM PPT precipitation [mm] 2!1N, 2W!1E; 19!27 climatology NOAA Global Historical Climatology Network data 14

39 Significant hemispheric correlations indicate that Atlantic SSTs play a role in orchestrating the variability Latitude 3 N 6 N W 9 W 6 W 3 W 3 E 6 E 9 E Longitude correlation ANNUAL (OCT-SEP) JERUSALEM PRECIPITATION CORRELATED WITH PRECIPITATION ELSEWHERE. TIME SERIES WERE SMOOTHED BY 1 PASS OF A 2-ND ORDER BINOMIAL FILTER. PRECIPITATION FROM GPCC

40 Levant Precipitation & No. Atlantic SST: an anti-phase relationship precipitation [mm] SOLID LINES = 15 YEARS LP BARS = JERUSALEM HYDROLOGICAL YEAR PRECIPITATION Jan Jan Jan Jan Jan Jan Jan Jan Jan Time 16

41 Levant Precipitation & No. Atlantic SST: an anti-phase relationship precipitation [mm] SOLID LINES = 15 YEARS LP BARS = JERUSALEM HYDROLOGICAL YEAR PRECIPITATION NORTH ATLANTIC ANNUAL SST ANOM -.4 C -.2 C C.2 C.4 C sea surface temperature Jan Jan Jan Jan Jan Jan Jan Jan Jan Time 16

42 Correlations with Jerusalem ppt SST SLP 17

43 How Atlantic Multidecadal Variability influences Levant precipitation L H L 2 L 1 H L Z 5 HPA 1 H H -1 L SEA LEVEL PRESSURE The SLP difference between wet and dry years points at a seesaw between the Eastern Atlantic and the Eastern Mediterranean. Ziv et al. (26) (WARM ATLANTIC) MINUS (COLD ATLANTIC) KUSHNIR (1994)

44 How Atlantic Multidecadal Variability influences Levant precipitation L H L 2 L 1 H L Z 5 HPA cold air aloft = E. Med. cyclogenesis -1 1 H L H SEA LEVEL PRESSURE The SLP difference between wet and dry years points at a seesaw between the Eastern Atlantic and the Eastern Mediterranean. Ziv et al. (26) (WARM ATLANTIC) MINUS (COLD ATLANTIC) KUSHNIR (1994)

45 Simulation of orbital forcing (25) 19

46 Trop. Atl. Teleconnections TAGA exp: 16 member ensemble with 3 S-3 N Atl. SST prescribed from obs ) Figure: Ensemble mean SLP & PPT, regressed on trop. No. Atl. SST Drying over US Southwest when trop. No. Atl. is warm Low pressure over No. Atl. in both seasons. High pressure over No. Pac. in winter. 2

47 Late Holocene Record Bookman et al. (24) Scaeffer et al. (29) 21

48 Summary Atlantic SST variability is playing an important role in controlling decadal-to-centennial variability of precipitation in the Levant during the Holocene This role is emphasized by almost hemispheric linkages in land precipitation (Levant-North Africa- North America) It is important to consider this natural climate variability in future projections and verify that global climate models can simulate it What is the nature of the abrupt Holocene events that exhibit synchroneity over a broad spatial domain 22