INFLUENCE OF ATMOSPHERIC INFLUENCE OF ATMOSPHERIC TELECONNECTION PATTERNS TELECONNECTION PATTERNS

ON PRECIPITATION AND ON PRECIPITATION ANDUPWELLINGUPWELLING

M. Gómez- Gesteira1*, M. deCastro1, I. Alvarez1, M.N. Lorenzo1, A.J.C. Crespo and J.J Taboada2

1Grupo de Física de la Atmósfera y del Océano, Universidad de Vigo, Ourense, Spain2METEOGALICIA

* E-mail: mggesteira@uvigo.es

Miño River

Area under ScopeArea under Scope

351 352350

42 N

42.5 N

43 N

43.5 N

44 N

Galicia

Iberian Peninsula

Ekman

Transport

Ekman

Transport

Ekman

Transport

Ekman

Transport

Ekman

Transport

Ekman

Transport Miño River

Rain- Gauge Station Mean Precipitación DJF

(mm)

FONSAGRADA (FONS) 372.83

MONTEDERRAMO (MONT) 619.24

FOLGOSO DE CAUREL (FOLC) 607.40

VAO (VAO) 421.91

O BOLO (BOLO) 301.00

MONFORTE DE LEMOS 'E.AGRICOLA' (MOF1)

308.28

CASTRO DE REI (CREI) 437.46

SAN ESTEBAN (SEST) 456.52

AIRA PADRON (AIRP) 688.65

PUEBLA DE BROLLON (PDBR) 349.39

SEOANE DO COUREL (SEOC) 583.82

VEIGA DE BRAÑAS (VEIB) 670.37

SEQUEIROS (SEQU) 342.52

ACIVEIROS (ACIV) 443.90

TRIVES 'SAN JUAN DEL RIO' (TRIV)

388.71

PARAMOS-GUILLAREI (PAGU) 680.60

ORENSE 'GRANJA DIPUTACION' (OURE)

302.04

MONFORTE 'A PINGUELA' (MOF2)

252.23

PUEBLA DE BROLLON 'VEIGA' (PDBV)

389.52

SARRIA 'GRANXA BARREIROS' (SARR)

475.00

ALLARIZ (ALLA) 329.79

LUGO 'COLEGIO FINGOI' (LUGO) 371.13

Frieira

Precipitation and Miño River dischargePrecipitation and Miño River dischargeM. deCastro et al., Climate Research 32 (2006)M. deCastro et al., Climate Research 32 (2006)

Mean monthly flow (Miño River) (Data from October 1970 to September 2005)

Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug SepOct Nov Dec Jan Feb Mar Apr May Jun Jul Aug SepOct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep

1975 1980 1985 1990 1995 2000

-1

0

1

2

3

4

Val

ore

s N

orm

aliz

ado

s

Normalized precipitation DJF (blue) y and river discharge (red) (Data from 1976 to 1997)

C.C.=0.88

1975 1980 1985 1990 1995 2000

-1

0

1

2

3

4

Val

ore

s N

orm

aliz

ado

s

Correlation between modes and river dischargeCorrelation between modes and river discharge

-1

-0.75

-0.5

-0.25

0

0.25

0.5

0.75

1

Desfase(meses)

Coe

fici

ente

Cor

rela

ción

NAO

EA

SCAND

EA/WR

0 1 432 5

Lead (months)

Index Correlation

NAO -0.54 (2)

SCAND 0.63 (1)

EA/WR -0.46 (1)

EA 0.40 (0)

Evolution of the correlation between modes and Evolution of the correlation between modes and river dischargeriver discharge

-0.8

-0.4

0

0.4

0.8

Coe

fici

ente

Cor

rela

ción

NAO EA EA/WR SCAND

Running period (22 years)

-0.8

-0.4

0

0.4

0.8

Coe

fici

ente

Cor

rela

ción

NAO EA EA/WR SCAND

Variability of Upwelling ConditionsVariability of Upwelling Conditions

1 2 3 4 5 6 7 8 9 10 11 12

-1000

-500

0

500

1000

1500

2000 Q

x (m

3 s-1k

m-1

)

Month

In Western Iberian Peninsula: UI = -QxQx < 0 upwelling favorable

Qx > 0 upwelling unfavorable y2/12

y2x

w

dax WWW

f

CQ

Zonal Ekman transport

Data 1966- 2005

Upwelling ConditionsUpwelling Conditions

0

10

20

30

1 2 3 4 5 6 7 8 9 10 11 12

Month

Days per month under upwelling favorable conditions

Atmospheric patterns vs QAtmospheric patterns vs Qxx during the wet season during the wet season (NDJF)(NDJF)M. deCastro et al., Jornal Marine Systems 72 (2008)M. deCastro et al., Jornal Marine Systems 72 (2008)

*** significance level > 95%

Correlation between atmospheric modes and Qx from 1966 to 2005.

EA NAO EA/WR POL SCAND

Qx (NDJF) 0.65*** -0.19 0.16 -0.16 0.12

-2

0

2

4

1966 1971 1976 1981 1986 1991 1996 2001

Qx EA

-1

-0.5

0

0.5

1

1967 1971 1975 1979 1983 1987 1991 1995 1999 2003

EA

-400

-200

0

200

400

1967 1971 1975 1979 1983 1987 1991 1995 1999 2003

Qx

anom

aly

(m3 s-1

km

-1)

EA Pattern Evolution

EA > 0 associated to southerly winds at Galician shelf

Positive values from 1983 on, which result in upwelling unfavorable conditions

Qx Anomaly Evolution

SLP composites

Atmospheric patterns vs summer UIAtmospheric patterns vs summer UISSTSST

M. deCastro et al., Climate Research 36 (2008)M. deCastro et al., Climate Research 36 (2008)

Atmospheric patterns vs UIAtmospheric patterns vs UISSTSST

•Precipitation/river discharge depend on several indices (NAO,

SCAND, EA/WR, EA)

•The dependences is not stationary

Summary:Summary:

•Winter upwelling in Galician region depends on EA

•Winter upwelling tends to decrease during the last decades

•Summer upwelling depends on EA and NAO along the Western Iberian Coast

•Dependence on NAO decreases northward

Thanks!!!Thanks!!!

Dates UIAM (ºC) EA

Sep 88 -2.23 0.7

Sep 94 -2.52 -0.5

Aug 96 -1.89 0.6

Aug 98 -2.29 2

Sep 98 -2.06 0.4

Oct 98 -1.97 1.2

Aug 01 -2.07 2.6

Aug 02 -2.76 0.2

Sep 05 -2.08 1.7

NAO and EA . Map of Correlations with precipitation departuresNAO and EA . Map of Correlations with precipitation departures

Dry winter in Galicia

NAO with a positive phase

Above- average precipitation during winter in Galicia

EA with a positive phase

DJF average DJF average

Correlación Modos vs. PrecipitaciónCorrelación Modos vs. Precipitación

DEF coeficientes invernales de correlación de los distintos índices de teleconexión y la precipitación de las estaciones situadas (Octubre 1976 - Septiembre 1997)

Correlación Modos vs. Correlación Modos vs. PrecipitaciónPrecipitación

1975 1980 1985 1990 1995 2000

-1.0

0

1.0

2.0

3.0

4.0

1975 1980 1985 1990 1995 2000

-1.0

0

1.0

2.0

3.0

4.0

1975 1980 1985 1990 1995 2000

-1.0

0

1.0

2.0

3.0

4.0

1975 1980 1985 1990 1995 2000

-1.0

0

1.0

2.0

3.0

4.0

NAO EA

EA/WR SCAND

Variación interanual de los modos promediados a DEF (línea roja) y las precipitaciones (línea azul)

(Octubre 1976-Septiembre 1997)