A new Deep Water formed in the A new Deep Water formed in the NW Mediterranean in 2005 NW Mediterranean in 2005 J. Font (1), J. Salat (1), M. Emelianov (1), P. Puig (1), A. Palanques (1), A. Julià (1), J.L. López-Jurado (2), C. González-Pola (3) and J. Flos (4) (1) Institut de Ciències del Mar CSIC, Barcelona, Spain (2) Instituto Español de Oceanografia, Palma de Mallorca, Spain (3) Instituto Español de Oceanografia, Gijón, Spain (4) Universitat de Barcelona, Barcelona, Spain (contact: [email protected])
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A new Deep Water formed in the NW Mediterranean in 2005 J. Font (1), J. Salat (1), M. Emelianov (1), P. Puig (1), A. Palanques (1), A. Julià (1), J.L.
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A new Deep Water formed in the NW A new Deep Water formed in the NW Mediterranean in 2005Mediterranean in 2005
J. Font (1), J. Salat (1), M. Emelianov (1), P. Puig (1), A. Palanques (1), A. Julià (1), J.L. López-Jurado
(2), C. González-Pola (3) and J. Flos (4)
(1) Institut de Ciències del Mar CSIC, Barcelona, Spain
(2) Instituto Español de Oceanografia, Palma de Mallorca, Spain
(3) Instituto Español de Oceanografia, Gijón, Spain
NW Mediterranean, a well known site for dense water formation (1)
Westen Mediterranean Deep Water (WMDW) Westen Mediterranean Deep Water (WMDW)
Open sea convection
Where:
offshore the Gulf of Lions: MEDOC area (42º N, 5º E)
How:
1. Salty LIW is brought to near surface due to winter convection
2. Mixing with surface “old” AW + intense cooling and evaporation (Mistral wind) = WMDW violent sinking during strong Mistral episodes. LIW upwelling is maintained to compensate sinking.
3. New WMDW spreads in the deep ocean Schott and Leaman, JPO, 1991
NW Mediterranean, a well known site for dense water formation (2)
Western Intermediate Waters (WIW)Western Intermediate Waters (WIW)
Open sea convection
Where:
near the northern continental slope
How:
1. Surface relatively less salty water, “recent” AW brought by the Northern current + intense cooling and evaporation = WIW sinking above the LIW layer (up to 400 m).
2. New WIW spreads along the slope advected to the south by the Northern current.
NW Mediterranean, a well known site for dense water formation (3)
Other dense waters
CascadingCascading
Where:
over the shelf
How:
1. Surface lower salinty (river influenced) water + intense cooling and evaporation (Mistral wind) = dense water sinking to the bottom of the shelf to reach the slope.
2. Cascading over the slope and canyons down to match its density. Typically WIW layer. Exceptionally deeper if winter is very cold, windy or dry
Acronym θ (°C) S σθ (kg·m-3)"recent"AW >13 <37.2 <28.1
"old"AW > 13 38.0-38.2 < 28.9WI W 12.6-13.0 38.1-38.3 28.9-29.0LI W 13.0-13.4 38.48-38.55 29.075
WMDW 12.75-12.82 38-43-38.47 29.115-29.120
NW Mediterranean Water masses
LIW
WIW
WIW
LIW
WMDW
Exceptional 2004-2005 winter
Precipitation on the W Mediterranean catchment area during winter 2004-2005 was very scarce. Minimum absolute values ever recorded in many of the meteorological stations.
From 25 January to 10 March, 2005, air temperatures were lower, especially daily maxima, than the climatological average, and northerlies were strong and persistent
Maximum NCEP heat flux since 1948 (72% above average)
Fevrier 2005:Sur 16 jours de tramontane , le vent a atteint ou dépassépendant quatre jours les 100 km/h.Le 28 Février un record du maximum le plus bas a été battu àPERPIGNAN: 1.5°C (précédent record: 3.8°C en 1934)
Janvier 2005:Sur dix-huit jours de tramontane , le vent a atteint ou dépassépendant trois jours 100 km/h.
From climatological summaries of MétéoFrance for the Mediterranean coast
Sequence of Chl_a daily images
January - March 2005: Dense water formation area (identified by low
Chl_a) very persistent and extense
BARC ELO N A
CATALU NYA
M EN O R C A
M ALLO R C A
M AR SELLA
40º N
42º N
44º N
1º E 3º E 5º E
1000
2000
200
2000
1000
200
200
200
Francoli R.
Foix R.
Llobregat R.Besos R.
Tordera R.
Ter R.
Fluvia R.
Tet R.
Erau R.
P. Rhone R.
G.Rhone R. Durance R.
EbroR.
CIESM Hydro-Changes CSIC mooring 41º 28’ N / 3º 40.4’ E 1845-m depthT, S, and current (October 2003 - July 2005)
EuroStrataform CSIC moorings Cap de Creus C. 200, 500 and 750-m depthT, S, Turb. and current (September 2004 - April 2005)
3º 00' 3º 30'
41º 30'
42º 00'
Ter R.
Fluvià R.
Cap de CreusCanyon
PalamósCanyon
BlanesCanyon
100
200400
600 8001000
12001400
1600
1800
2000
2200
2400
2200
Moorings in NW Mediterranean
Intense events in early 2005, followed by a new warmer, saltier steady state
CIESM Hydro-Changes site Records at 1830 m
Very intense current when the most dense water arrives
3º 4º 5º
42º
43º100
150200
500
1000
2000
2500
EuroStrataform winter 2003-2004
Nov-03 Dec-03 Dec-03 Jan-04 Feb-04 M ar-04 Apr-04
1 11 21 31 41 51 6
1 11 21 31 41 51 6
1 11 21 31 41 5
1 21 31 41 5
1 21 31 41 5
Te
mp
era
ture
(ºC
)
1 21 31 41 5
1 21 31 41 5 Planier
G rand Rhone
Petit Rhone
H erault
Aude
Lacaze-D uhiers
C ap de C reus
Monitoring of 7 submarine canyon heads at 300-m depth
Shelf water cascading, preferably towards the W sector
Palanques, A., Durrieu de Madron, X., Puig, P., Fabrés, J., Guillén, J., Calafat, A., Heussner, S., Canals, M., Boninn, J. (2005). Suspended sediment fluxes and transport processes in the Gulf of Lions submarine canyons. The role of storms and dense water cascading. Marine Geology, submitted.
- 1.5 ºC
3º 00 ' 3º 10 ' 3º 20 ' 3º 30 '42º 30 '
42º 20 '
42º 10 '
150200
500
50
100
200 m
500 m
750 m
Sep-04 O ct-04 Nov-04 Dec-04 Jan-05 Feb-05 M ar-05
0
20
40
60
80
100
0
20
40
60
80
100
Cu
rre
nt
spe
ed
(cm
s -
1)
0
20
40
60
80
100
200 m
500 m
750 m
EuroStrataform winter 2004-2005
Focused study in the Cap de Creus canyon head
Intense (earlier and longer) shelf water cascading
8
10
12
14
16
8
10
12
14
16
Te
mp
era
ture
(ºC
)
8
10
12
14
16
200 m
500 m
750 m
- 3 ºC
+ 70 cm/s
CIESM Hydro-Changes + EuroStrataform sites
Current direction
Diagrama TS per totes les dades de la campanya de l'ACA dels camps llunyà i mitjà l'hivern de 2005
SALINITAT
37.0 37.5 38.0 38.5 39.0
TE
MP
ER
AT
UR
A
9
10
11
12
13
14
15
16
Estacions hivern 05
29.0
27.5 28.028.5
Aigua fonda del Mediterrani Occidental
30,0
29.5
Trabucador
Alcanar
Punta de la Banya
Catalan coast monitoring in winter 2005: shelf stations
WMDW
Open sea: “EFLUBIO-3” cruise B/O “Cornide de Saavedra” 15 March - 6 April 2005
15-22 March
24 March-06 April
Underway surface salinity
Potential density at 25 m
MEDOC area
MEDOC + other open sea areas
Cross-slope section near Barcelona: no front, LIW ascent
WMDW: O 12.75-12.82 38-43-38.47 29.115-29.120 WMDW: N 12.87-12.90 38.47-38.49 29.12 WMDW: C 12.72-12.78 38.45-38.47 29.13
CONCLUSIONS
The anomalously dry, windy and relatively cold 2004 – 2005 winter produced an intense deep convection covering a long period and larger area:
The smaller fresh water inputs and limited supply of recent AW, plus strong winds, produced a widespread cascading over the shelvesrecorded in the coastal monitoring
•Type C WMDW formation
recorded at the mooring while falling downslope to deeper areas of the W Mediterranean and at the Barcelona slope cross-section
A large amount of LIW is brought to near surface over the area typically occupied by the relatively recent AWrecorded by surface underway analysis during the cruise: especially from the MEDOC area to Barcelona and at the Barcelona slope cross-section
• Type N WMDW formation where WIW is typically producedrecorded at many cruise stations: MEDOC area, North and East of Balearic Islands(+ saltier LIW? + more LIW from Sicily channel?)
• Type O WMDW formation in open seasrecorded at many cruise stations: MEDOC area, North and East of Balearic Islands
Summer 2005, open sea
TUNIBAL St. 321 Latitude: 40 40.15 N Longitude: 03 23.30 E 15 July 2005
A new deep water structure is present in the NW Med
Are we sensing the effects of the Eastern Mediterranean Transient?
And for sure the dramatic effects of an anomalously dry and windy winter