principal sequence pattern analysis of episodes of …

PRINCIPAL SEQUENCE PATTERN ANALYSIS OF EPISODES OF EXCESS MORTALITY DUE TO HEAT

IN THE BARCELONA METROPOLITAN AREA

Peña J.C.1, 2, Aran M.1, Raso J.M.3, Pérez-Zanón, N.4 [1]{Servei Meteorològic de Catalunya, Barcelona, España} [2]{Grup d’investigació PaleoRisk, Universitat de Barcelona, Barcelona, España} [3]{Grupo de Climatología, Universitat de Barcelona, Barcelona, España} [4]{Centre for Climate Change (C3), Universitat Rovira i Virgili}

CONTENTS

Introduction

Objectives

Threshold value

Sequence length: Data, Methods and Results

Principal Sequence Pattern Analysis:

1. Methods

2. PSPA Results

3. Are realistic the results?

4. Monthly frequency and trend analysis of sequences patterns (1871-2008)

Conclusions

Principal Sequence Pattern Analysis applied to episodes characterized by a mortality increased because of heat in the Barcelona metropolitan area Peña J.C., Aran M., Raso J.M., Pérez-Zanón, N.

XXI JORNADES DE METEOROLOGIA EDUARD FONTSERÈ:

Servei Meteorològic de Catalunya (SMC)

Group of Climatology (UB)

Climate-Health

Peña, J.C, Raso, J. M., 2010: El aviso de la situación meteorológica de riesgo por frío emitido por el Servei Meteorològic de Catalunya: definición de los umbrales, sectorización territorial y peligrosidad del fenómeno, en FERNÁNDEZ, F., GALÁN, E. y CAÑADA, R. (Eds) Clima, ciudad y ecosistemas.

Peña, J.C., Pérez, N., Raso, J.M., Arán, M., 2012: Secuencias de patrones sinópticos asociados al exceso de mortalidad por calor en el área metropolitana de Barcelona, en Rodríguez, C., Ceballos, A., González, N., Morán., E. y Hernández, A. Cambio climático, extremos e impactos, 907-915

Peña, J.C., Raso, J.M., Pérez, N., Arán, M., 2012: Duración de la secuencia como unidad temporal básica para el análisis de los antecedentes sinópticos que repercuten en el excesos de mortalidad por frío/calor en Cataluña. Nimbus, (29-30): 563-571.

Raso, J.M., y Peña, J.C., 2013: La necesidad de soporte a la población de Barcelona ante el impacto potencial de un incremento climático de la temperatura ambiente. POLÍGONOS, Revista de Geografía, (24):95-131.

SMC

CSOC

Peña J.C., Aran M. Cunillera, J. and Amaro J., 2011: Atmospheric circulation patterns associated with strong wind events in Catalonia, Nat Hazards Earth Syst Sci 11, 145–155.

Aran, M., Peña, J. C. and Torà, M., 2011: Atmospheric circulation patterns associated with hail events in Lleida (Catalonia), Atmos. Res., 100, 428-438.

Aran M., Pérez-Zanón N., Peña J.C., 2011: Atmospheric circulation pattern sequences producing torrential intensities in the Catalan coastal area, Spain. 6th European Conference on Severe Storms (ECSS 2011) , 3 - 7 October 2011, Palma de Mallorca, Balearic Islands, Spain.

Aran M., Peña J.C., Pineda N., Soler X., Pérez-Zanón N., 2015. Ten-year lightning patterns in Catalonia using Principal Component Analysis. European Conference on Severe Storms 2015, 14–18 September 2015, Wiener Neustadt, Austria, ECSS2015-PREVIEW

Peña, J.C., Pérez-Zanón, N., Aran, M., Rius, A., Casas-Castillo, M.C., Rodríguez-Solà, R., Redaño, A., and Solé, G., 2015: Analysis of meteorological temporal scales and synoptic types related to episodes of severe rainfall in the southern part of Catalonia (Spain). Research progress on climate change detection and projections for Spain from the IPCC AR5 findings, Tortosa, Catalonia, Spain, 11-13 March, 2015.

Peña, J.C., Aran, M., Pérez-Zanón, N., Casas-Castillo, M.C., Rodríguez-Solà, R., Redaño, A. 2015: Análisis de las situaciones sinópticas correspondientes a episodios de lluvia severa en Barcelona. XXXV Reunión Bienal de la Real Sociedad Española de Física. Física de los procesos climáticos en atmósferas y océanos. Gijón, Julio 2015.

PaleoRisk Group (UB)

Climate-Floods

Peña, J.C. and Schulte, L., 2014: Effects of solar activities and climate variability on large floods in Switzerland, Bol. Asoc. Geóg. Españoles, 65, 469-475.

Peña, J.C. y L. Schulte, 2014. Control del forzamiento solar y de los patrones de circulación atmosférica de baja frecuencia en las avenidas de verano en suiza, in: Avances de la Geomorfología en España 2012-2014 (Susanne Schnabel y Álvaro Gómez Gutiérrez, (editores). XIII Reunión Nacional de Geomorfología, Cáceres, 131-134.

Schulte, L., J.C. Peña, R. Julià, F. Carvalho, J. Llorca, J. Losada, F. Burjachs, T. Schmidt , P. Rubio, H. Veit: Climate forcing of paleofloods in the Swiss alps, in: Avances de la Geomorfología en España 2012-2014 (Susanne Schnabel y Álvaro Gómez Gutiérrez, (editores) XIII Reunión Nacional de Geomorfología, Cáceres, 143-146, 2014.

Peña, J.C., Schulte, L., Badoux, A., Barriendos, M. and Barrera-Escoda, A., 2015: Influence of solar forcing, climate variability and modes of low-frequency atmospheric variability on summer floods in Switzerland, Hydrol. Earth Syst. Sci., 19, 3807–3827, doi:10.5194/hess-19-3807-2015.

Peña J.C., Aran M., Raso J.M. and Pérez-Zanón N., 2015: Principal sequence pattern analysis of episodes of excess mortality due to heat in the Barcelona metropolitan area, Int J Biometeorol, 59, 435-446, doi: 10.1007/s00484-014-0857-x.

Sequence length Principal Sequence Pattern Analysis INTRODUCTION Threshold value Objectives Conclusions

CONTENTS

Introduction

Objectives

Threshold value



1. Methods

2. PSPA Results



Conclusions



The purpose is to define the synoptic sequence patterns associated with excess mortality attributable to the temperature during the warm season in the Barcelona Metropolitan Area. Other authors have studied the relation between heat and mortality, e.g. Xu et al. (2013) focused the study in Barcelona. However, a new novelty approach based on synoptic sequences as a triggering mechanism on mortality by heat wave is proposed.

OBJECTIVES

Sequence length Principal Sequence Pattern Analysis Introduction Threshold value OBJECTIVES Conclusions

CONTENTS

Introduction

Objectives

Threshold value



1. Methods

2. PSPA Results



Conclusions



SMP NIVELL BAIX NIVELL ALT

Calor Temperatura màxima extrema: superació del percentil 98 de la temperatura màxima diària

Onada de calor: superació del percentil 98 de la temperatura màxima diària durant tres dies consecutius

SMP NIVELL BAIX NIVELL ALT

FRED Temperatura mínima extrema: superació del percentil 2 de la temperatura mínima diària

Onada de fred: superació del percentil 2 de la temperatura mínima diària durant tres dies consecutius

Situació Meteorològica de Perill (SMP) per calor i fred

Sequence length Principal Sequence Pattern Analysis Introduction THRESHOLD VALUE Objectives Conclusions

CONTENTS

Introduction

Objectives

Threshold value



1. Methods

2. PSPA Results



Conclusions



The sequence length was determined by the short-term displacement between temperature and mortality

Temperature residuals Mortality residuals

Data and Methods

SEQUENCE LENGTH Principal Sequence Pattern Analysis Introduction Threshold value Objectives Conclusions

CCF GENERAL FEATURES

Mortality vs maximum temperature Period: June, July and August (1990-2006) Significant positive correlation between the lags -3 (D-3) y 0 (D) Temperature increase leads increased mortality The effects are immediate (almost without persistence) Sequence duration: Four days D + 3 previous days

Mortality vs minimum temperature Period: June, July and August (1990-2006) Significant positive correlation between the lags -6 (D-6) y 0 (D) Temperature increase leads increased mortality The persistence affects the mortality Sequence duration : Seven days D + 6 previous days

Mortality vs minimum temperature Period: December, January and February (1990-2006) Significant negative correlation between the lags -10 (D-10) y 0 (D) Temperature decrease leads increased mortality The persistence affects the mortality Sequence duration : Eleven days D + 10 previous days

CCF

Definition of Sequence duration from the Cross-Correlation Function

SEQUENCE LENGTH Principal Sequence Pattern Analysis Introduction Threshold value Objectives Conclusions

CONTENTS

Introduction

Objectives

Threshold value



1. Methods

2. PSPA Results



Conclusions



Adapted from Philipp, A (2009)

DATA BASE:

• SLP, T850 and Z500 anomalies taken from 20th Century Reanalysis V2 project, for the period 1871-2008 (Compo et al., 2011).

• The analysis was performed for those days exceeding the 95th percentile of the number of daily deaths (organic causes, both sexes and over 65 years) in the period 1990-2006 computed for the months of June, July and August.

INITIAL DATA MATRIX for the daily sequence analysis, where x[i],j represents SLP, T850 or Z500 anomalies, varying on the n grid points ([i]) and for each of the m sequences (j) T-MODE.

Principal Sequence Pattern Analysis (PSPA, Peña et al., 2015)

Model Validation: KMO and Bartlett’s test

Number of components: Scree-test

Rotation: Varimax

Final Patterns:

• the correlation coefficient was calculated between each of the patterns obtained from the PSPA (conducted for the period 1990-2006) and each of the n-day sequences extracted from the 20CRP for the JJA period

• The final patterns (extending from 1871 to 2008) are the composites constructed with the n-day sequences presenting a correlation coefficient greater than 0.65 related to, at least, one pattern.

• If a sequence was associated with more than one PSPA pattern, that sequence was discarded.

Principal Sequence Patterns for the period 1990-2006

Sequence length PRINCIPAL SEQUENCE PATTERN ANALYSIS Introduction Threshold value Objectives Conclusions

INITIAL DATA MATRIX for the analysis of synoptic patterns of daily sequences, where x[i],j is the SLP, T850 or Z500 anomalies, varying on the m points of grid (j) and for each of the n events ([i]) S-MODE.

Adapted of Philipp, A (2009)

Multivariate Analysis (Peña et. al. 2011) Classify sequence patterns to daily resolution for various atmospheric levels ● PCA (Principal Components Analysis) in S-Mode Reducing the number of variables. ● CA (Cluster Analysis)-Hieratic (Ward Method) Obtaining the number of clusters. ● CA- K-means Identification of the n patterns ● DA (Discriminant Analysis ) Model validation


CONTENTS

Introduction

Objectives

Threshold value



h Methods

2. PSPA Results



Conclusions



SEQUENCE LENGHT PRINCIPAL SEQUENCE PATTERN ANALYSIS INTRODUCTION THRESHOLD VALUE Sequence length PRINCIPAL SEQUENCE ANALYSIS Introduction Threshold value

Scree Test: 3 components that explain 45% of the variance

0,776

Chi-square 503695,856

degree of freedom 1128

Sig. 0

KMO and Bartlett's test

Measure of sampling adequacy Kaiser-Meyer-Olkin

Bartlett's sphericity test

1) Model Validation: KMO and Bartlett’s test

>0,5 OK¡

2) Election of the number of components Scree Test:

3) Final Patterns Number of sequences for each cluster

PSP for 1990-2006. Correlation coefficient between T850 PSP pattern and sequences for the period 1871-2008

r >0.65 Final Patterns

PSPA RESULTS (1990-2006) Minimum temperature: T-MODE


MULTIVARIATE ANALYSIS (1990-2006): Maximum temperature

First Step: Reduction of variables PCA (in S-Mode)

Second step: Classification CA (36 variables)

Third step: Model Validation DA

Jump Method: 3 clusters

SLP Scree Test: 12 variables, 77% explained variance T850 Scree Test: 13 variables, 74% explained variance Z500 Scree Test: 11 variables, 76% explained variance

Correctly classified 100.0% of original clustered cases. Correctly classified 97.6% of clustered cases validated by cross-validation.

PSP for 1990-2006. Correlation coefficient between T850 PSP pattern and sequences for the period 1871-2008

r >0.65 Final Patterns


RESULTS FINAL SEQUENCE PATTERNS: North Atlantic Low (NAL, r=0.965). Period: 1871-2008

T850 Anomalies (ºC) Z500 Anomalies (meters) SLP Anomalies (hPa)


RESULTS FINAL SEQUENCE PATTERNS: Central Atlantic Low (CAL, r=0.936). Period: 1871-2008



RESULTS FINAL SEQUENCE PATTERNS: Blocking pattern (BL, r=0.936). Period: 1871-2008



D-3

D-2

D-1

D

RESULTS MULTIVARIATE ANALYSIS. Mediterranean Pattern (r=0.924). Period: 1871-2008



RESULTS MULTIVARIATE ANALYSIS. Iberian Pattern (r=0.875). Period: 1871-2008

D-3

D-2

D-1

D

Anomalías T850 (ºC) Anomalías Z500 (metros) Anomalías SLP (hPa)


RESULTS MULTIVARIATE ANALYSIS. European Pattern (r=0.901). Period: 1871-2008

D-3

D-2

D-1

D

Anomalías T850 (ºC) Anomalías Z500 (metros) Anomalías SLP (hPa)



North Atlantic Low (NAL)

• This pattern is characterized by the Atlantic depression to the west of the British Isles, south of Iceland, producing a warm air advection from the southwest to the northeast over Central Europe, most notably in the easternmost part of the continent.

• The area of the Iberian Peninsula

that is most affected is the centre and northwest quadrant, which presents a temperature anomaly at the 850 hPa geopotential level above +2.5 °C for the entire sequence.


Central Atlantic Low (CAL) • The synoptic configuration of this

pattern is characterized by a displacement of the Atlantic low in southwestward direction, advecting warm air from the lower latitudes to Europe.

• The configuration is enhanced in

Northern Europe by the presence of strong anticyclonic conditions over this area. Positive temperature anomalies at the 850 hPa level extend in a south-north direction, affecting central and northern areas of the continent.

• The area of the Iberian Peninsula

that is most affected is the northern section, which presents thermal anomalies above +2.5 °C between the sequence days D-3 and D.


Blocking pattern (BL)

• This pattern shows a long-lived, blocking anticyclonic ridge over Western Europe, with the Atlantic low located to the southwest of the Iberian Peninsula, producing a weak warm air advection from the southeast to the northwest over Southern Europe.

• This is followed by the stagnation of the configuration due to the strong anticyclonic conditions in Northern Europe. Positive temperature anomalies at the 850 hPa level primarily affect the westernmost part of the European continent.

• These anomalies are intense in France, the British Isles and the northwest of the Iberian Peninsula, with values above +3 °C during the seven days of the sequence in these areas. The situation is highly persistent, intensifying the high pressure centre from sequence day D-5 with the action centres remaining unchanged throughout the period, although there is a slight shift to the northwest during the course of the days.

CONTENTS

Introduction

Objectives

Threshold value



h Methods

h PSPA Results



Conclusions



RESULTS FINAL SEQUENCE PATTERNS: North Eastern Pattern

Daily minimum temperature anomalies calculated for the period 2000-2008 from automatic weather stations managed by the Meteorological Service of Catalonia


CONTENTS

Introduction

Objectives

Threshold value



h Methods

h PSPA Results

h Are realistic the results?


Conclusions



CONTENTS

Introduction

Objectives

Threshold value



h Methods

h PSPA Results


h Monthly frequency and trend analysis of sequences patterns (1871-2008)

Conclusions



• In consequence, the excess mortality recorded in the Barcelona Metropolitan Area during the summer months can be related to atmospheric conditions that produce extremely high temperatures, involving synoptic patterns that cause heat waves both in Southern and Central Europe (Atlantic Low pattern) and in Northern and Western Europe (Blocking pattern).

Sequence length Principal Sequence Pattern Analysis Introduction Threshold value Objectives CONCLUSIONS

• The purpose of the study was to classify the synoptic sequences at different atmospheric levels associated with excess mortality due to temperature during the summer season in the Barcelona Metropolitan Area, using PSPA.

• The sequence length was calculated using the CCF, applied to the residuals obtained from the modelling of the daily minimum temperature and mortality series, by means of an ARIMA model, taking into account significant lag times, i.e., those above the 95% confidence level. The results presented positive correlation coefficients, indicating that higher temperatures result in increased mortality. A seven-day sequence emerged as the basic temporal unit for evaluating the synoptic background influencing excess mortality due to heat in the Barcelona Metropolitan Area.

• PSPA was applied to seven-day sequences following a sequence key (D) defined by the days on which the daily mortality in the Barcelona Metropolitan Area exceeded the 95th percentile.

1. The analysis identified three main patterns with a general synoptic configuration characterized by the presence of negative anomalies over the Atlantic at the three atmospheric levels analysed, with southerly flows in the lower levels of the atmosphere that transport hot air from North Africa, causing warm air advection over Europe.

2. These three patterns are similar to the two synoptic modes that have been related to heat waves in Europe: the Atlantic Low pattern and the Blocking Pattern.

3. Two configurations are dynamic situations produced by southern fluxes and are connected with the heat waves recorded in the Iberian Peninsula.

I. Synoptic Sequence Pattern 1, referred to as the North Atlantic Low (NAL), is associated with the Atlantic Low pattern.

II. Synoptic Sequence Pattern 2, referred to as the Central Atlantic Low (CAL), is related to both European patterns: southern fluxes (Atlantic Low) and high pressures over Northern Europe (Blocking Pattern).

4. Synoptic Sequence Pattern 3 is associated with a blocking situation (BL) and is identified by a stagnation configuration associated with the persistence of a high pressure system over Europe. This pattern is related to the heat waves recorded in northern and central Western Europe.

CONTENTS

Introduction

Objectives

Threshold value



h Methods

h PSPA Results


h Monthly frequency and trend analysis of sequences patterns (1871-2008)

Conclusions



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principal sequence pattern analysis of episodes of …

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