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Ventilation of Ocean Heat along the Western Antarctic Peninsula 12 years of Palmer LTER Data

Ventilation of Ocean Heat along the Western Antarctic Peninsula 12 years of Palmer LTER Data. LDEO/Columbia University. Martinson. Douglas G. Martinson Lamont-Doherty Earth Observatory Columbia University dgm@ldeo.columbia.edu. mstecker.com/pages/antsatmap.htm.

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Ventilation of Ocean Heat along the Western Antarctic Peninsula 12 years of Palmer LTER Data

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  1. Ventilation of Ocean Heatalong theWestern Antarctic Peninsula12 years of Palmer LTER Data LDEO/Columbia University Martinson Douglas G. Martinson Lamont-Doherty Earth Observatory Columbia University dgm@ldeo.columbia.edu mstecker.com/pages/antsatmap.htm Photo: Dr. R.C. Smith, Sep. 2001 Martinson, 4/07/06; UCLA: WAP Heat

  2. 0.107˚ C/year Significant at 0.05 ~5.4x global average Motivation • Western Antarctic Peninsula • Most rapid recent regional winter warming on Earth • Major loss of perennial sea ice • 87% of glaciers are in retreat Vaughan et al., 2003 Perennial Ice Stammerjohn et al., 2006 Cook et al., 2005

  3. An. B. - A. -60 Bellingshausen Sea Ad. Sample region Location Map & Grid R. COAST L. SHELF SLOPE M.B.

  4. PAL LTER Grid (1992-2004) WOCE SP04: WAP ACC (February 1992) NBP94-04: Bellingshausen Slope (March 1994) Major global volumetric modes 3.5–4˚C #31 #33 #51 #55 #59 Background Source of Winter Heat 34.75 34.54 2.13˚ ACC-core UCDW 1.70˚ ANTARCTIC (summer) SURFACE WATERS (AASW) WW

  5. Antarctic Circumpolar Current SHELF SLOPE COAST wAP is unique as only location with ACC directly adjacent to shelf Proximity of ACC The Southern Ocean PAL LTER Sampling Grid Bellingshausen Sea Weddell gyre Bellingshausen Sea Amundsen Sea Ross gyre

  6. Temperature (˚C) UCDW Delivery Slope (~20 km off-shelf) Temperature Depth (db) Temperature section 2000 2001 Depth (db) 2002 2003 Grid line Grid line

  7. F w CO2 Uptake r, S summer T summer Biology Tf, S, r Tf, S, r winter winter CO2, PO, etc. CO2, PO, etc. Heat, nuts and CO2 Ventilation TD, SD, rD TD, SD, rD CO2D, POD, etc. CO2D, POD, etc. Shelf heat flux Seasonal Cycle Martinson and Takahashi, in prep

  8. ^  Shelf heat flux <Kz> m2/s x10-4 m2/s x10-4 Grid Line (km) Grid Station (km) Grid Station (km)

  9. <FTBP>W = 29.67 Wm2 (Martinson & Iannuzzi, 1998) <FTObs>W = 27.7 Wm2 (McPhee et al., 1999) Shelf heat flux FT: Bulk Parameter vs Measured (AnzFlux, 1994)

  10. Figure 4 Total ocean heat flux Wm-2 m  FT

  11. Temperature section Temperature (˚C) Shelf heat flux Slope (~20 km off-shelf) Temperature Qslope Depth (db) 2000 2001 Lucky Year: Depth (db) 2002 2003 Grid line Grid line

  12. Ocean heat flux (FT) to atmosphere over wAP shelf • shows considerable change in latter part of 1900s • (coinciding with increased Tair and glacial melt): • Large step increase in 1990 (>3 Wm-2) • Qshelf & Qslope are proxies for FT • FT shows a comparable shift via a trend throughout the LTER sampling period

  13. PAL LTER Grid (1992-2004) WOCE SP04: WAP ACC (February 1992) NBP94-04: Bellingshausen Slope (March 1994) Future Better Estimate of Q 34.75 34.54 2.13˚ UCDW 1.70˚ DW Nonnegativity constraint: Ix ≥ 0 WW

  14. 1998 (Includes T; w/ local covariance matrix)

  15. What Have I Learned?

  16. FT variability Modes of ocean heat flux

  17. FT variability Lines 150-650 (average Q-shelf) r = 0.75 Qshelf (x109 J/m2) FT Wm-2

  18. ~0.7˚ C warming of 300 m column of water below winter mixed layer (+4 W/m2 increased FT for same Qshelf) FT variability 1990–2004 Average Qslope = (3.83 ± 0.07 )x109 Qslope (x109 J/m2)  1930–1989 Mean Qslope = (2.98 ± 0.16)x109 rms about  NUMBER OF PROFILES PER AVERAGE YEAR

  19. FT variability Lines 150-650 (full shelf and coast stations) All shelf stations Qshelf (x109 J/m2) Year

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