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TS TRENDS IN THE WESTERN MEDITERRANEAN: WATER MASS CHANGES AND VERTICAL DISPLACEMENTS (HEAVING) Patricia Zunino Rodrígue

TS TRENDS IN THE WESTERN MEDITERRANEAN: WATER MASS CHANGES AND VERTICAL DISPLACEMENTS (HEAVING) Patricia Zunino Rodríguez Manolo Vargas Yáñez M. Carmen García Martínez Francina Moya. CLIVAR ESPAÑA 11-13 febrero 2009. 1. Trends in the Western Mediterranean: state of the art.

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TS TRENDS IN THE WESTERN MEDITERRANEAN: WATER MASS CHANGES AND VERTICAL DISPLACEMENTS (HEAVING) Patricia Zunino Rodrígue

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  1. TS TRENDS IN THE WESTERN MEDITERRANEAN:WATER MASS CHANGES AND VERTICAL DISPLACEMENTS(HEAVING) Patricia Zunino Rodríguez Manolo Vargas Yáñez M. Carmen García Martínez Francina Moya CLIVAR ESPAÑA 11-13 febrero 2009

  2. 1. Trends in the Western Mediterranean: state of the art • WMED deep waters have warmed and increased its salinity during the second half of the XXth century • WMED intermediate waters have increased its salinity • No robust results have been obtained related to temperature in the WMED intermediate waters CLIVAR ESPAÑA 11-13 febrero 2009

  3. 1943 1961 1948 2000 0 500 PRESSURE (dbar) 2500 2. How have these trends been estimated? Temperature and salinity profiles MEDAR database (2002) From 1943 to 2000 CLIVAR ESPAÑA 11-13 febrero 2009

  4. 1991 1991 SALINITY TEMPERATURE 2. How have these trends been estimated? anomaly - 100 dbar anomaly + 500 dbar CLIVAR ESPAÑA 11-13 febrero 2009

  5. Trends on isobaric surfaces don’t necessarily imply water mass changes 2. How have these trends been estimated? 100 dbar 0.006 ºC yr-1 0.5 Temperature anomaly 0 - 0.5 Time (year) 1943 2000 CLIVAR ESPAÑA 11-13 febrero 2009

  6. 3. Contribution to trends in each pressure level • Changes on isobaric surfaces can be decomposed into: a. Changes on isopycnal surfaces (changes in water masses) b. Vertical displacements (heaving, Bindoff & McDougall, 1994) • Both effects could add or cancel, enhancing or masking possible water mass trends in a determined pressure level CLIVAR ESPAÑA 11-13 febrero 2009

  7. T,S, = s T,S,= s 3. Contribution to trends in each isobaric level Q E - P • Changes on isopycnals (water mass changes): Related with the heat and freshwater exchange in the ocean-atmosphere interface 1000 dbar CHANGE ON ISOBARIC SURFACES AND CHANGE ON ISOPYCNAL SURFACES CLIVAR ESPAÑA 11-13 febrero 2009

  8. wind T T 3. Contribution to trends in each pressure level b. Isopycnal vertical displacement: marine dynamics NO WATER MASS CHANGE CLIVAR ESPAÑA 11-13 febrero 2009

  9. Q E-P T ,S, s V T ,S, s V Outflow 1000 dbr S T 29.096 Kg m-3 3. Contribution to trends in each pressure level b. Isopycnal vertical displacement: deep water formation NO WATER MASS CHANGE CLIVAR ESPAÑA 11-13 febrero 2009

  10. dq dq dp ∂θ = - dt dt dt ∂p isopycnal surfaces isobaric surfaces s heaving s z 3. Contribution to trends in each pressure level • How to estimate both contributions? • Bindoff & McDougall [1994] This decomposition have never been applied in the WMED, but it is so common in other world´s ocean CLIVAR ESPAÑA 11-13 febrero 2009

  11. 29.093 Kg m-3 29.096 Kg m-3 -14.02 ± 10.67 dbar yr-1 29.099 Kg m-3 4. Our results b) Results: Deep layer (600 dbar- bottom) TEMPERATURE ISOBARIC SURFACES ISOPYCNAL SURFACES HEAVING 0.0032 ± 0.0030 ºC yr-1 -0.0057 ± 0.0053 ºC yr-1 0.0075 ± 0.0071 ºC yr-1 CLIVAR ESPAÑA 11-13 febrero 2009

  12. 29.093 Kg m-3 0.0017 ± 0.0011 yr-1 29.096 Kg m-3 0.0023 ± 0.0010 yr-1 29.099 Kg m-3 0.0017 ± 0.0011 yr-1 4. Our results b) Results: Deep layer (600 dbar- bottom) SALINITY ISOBARIC SURFACES ISOPYNAL SURFACES HEAVING 0.0013 ± 0.0010 yr-1 -0.0012 ± 0.0011 yr-1 0.0023 ± 0.0021 yr-1 CLIVAR ESPAÑA 11-13 febrero 2009

  13. 29.068 Kg m-3 29.068 Kg m-3 0.0035 ± 0.0030 ºC yr-1 -4.35 ±3.45 dbar yr-1 29.089 Kg m-3 29.089 Kg m-3 0.0040 ± 0.0038 ºC yr-1 -9.53 ±9.12 dbar yr-1 4. Our results b) Results: Intermediate layer (200 - 600 dbar) TEMPERATURE 0.0058 ± 0.0054ºC yr-1 ISOBARIC SURFACES ISOPYCNAL SURFACES HEAVING -0.0048 ± 0.0032ºC yr-1 No significative trend CLIVAR ESPAÑA 11-13 febrero 2009

  14. 29.068 Kg m-3 - Salinity + -4.35 ±3.45 dbar yr-1 Pressure (dbar) 29.089 Kg m-3 -9.53 ±9.12 dbar yr-1 4. Our results b) Results: Intermediate layer (200 - 600 dbar) SALINITY ISOBARIC SURFACES ISOPYCNAL SURFACES HEAVING 0.0027 ± 0.0026yr-1 0.0019 ± 0.0017 yr-1 increase decrease -0.0008 ± 0.0007yr-1 0.0017 ± 0.0016 yr-1 CLIVAR ESPAÑA 11-13 febrero 2009

  15. 5. CONCLUSION • Subestimation of temperature and salinity trends of the deep waters masses when trends were estimated on isobaric surfaces • Intermediate waters in the WMED were warming during the last half century, which wasn't clear before • Upward displacement in the WMED during the second half of the XXth century , and thiswould be linked to the deep water formation rate in the Gulf of Lions and Levantine basin CLIVAR ESPAÑA 11-13 febrero 2009

  16. THANKS FOR YOUR ATENTION!!!!!

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