Analysis of the dynamics of extreme rainfall events in summer in southern Uruguay Matilde Ungerovich and Marcelo Barreiro UdelaR, Montevideo 8 May 2018
When I say Uruguay
When I say Uruguay When I say southern
When I say Uruguay When I say southern
When I say Uruguay When I say extreme: days in which the accumulated exceeds 90 percentile When I say southern
Objective of this investigation
Objective of this investigation Understand the main characteristics and atmospheric patterns that influence the extreme events of rainfall in summer in southern Uruguay
Motivation
Motivation Uruguay is an agricultural country, whose economy is greatly affected by the accumulation and distribution of rainfall
Motivation Uruguay is an agricultural country, whose economy is greatly affected by the accumulation and distribution of rainfall Extreme rainfall events generate social damages such as population displacement and road closures
Motivation Uruguay is an agricultural country, whose economy is greatly affected by the accumulation and distribution of rainfall Extreme rainfall events generate social damages such as population displacement and road closures There is no investigation on extreme rainfall events in Uruguay
1980 1984 1988 1992 1996 2000 2004 2008 2012 Motivation Uruguay is an agricultural country, whose economy is greatly affected by the accumulation and distribution of rainfall Extreme rainfall events generate social damages such as population displacement and road closures There is no investigation on extreme rainfall events in Uruguay Accumulated rainfall in extreme events % 0 10 20 30 40 50 60 70 80 90 100
Data
Data Daily data, period 1980-2013
Data Daily data, period 1980-2013 Observational accumulated rainfall in 15 pluviometers
Data Daily data, period 1980-2013 Observational accumulated rainfall in 15 pluviometers NCEP reanalysis 2-2.5 o x2.5 o : geopotential height, wind, temperature, latent heat
Methodology
Methodology EOF to classify the extreme events in different categories
Methodology EOF to classify the extreme events in different categories Composite analysis to study the dynamics (90% significance)
EOF- empirical orthogonal function
EOF- empirical orthogonal function The EOF was calculated considering 2m temperature
EOF- empirical orthogonal function The EOF was calculated considering 2m temperature They repesent 48% and 17% of variability EOF1 EOF2 0.2 0.2 0.1 0.1 0.0 0.0 0.1 0.1 0.2 0.2 295 300 305 310 315 320 Longitud [ ] 295 300 305 310 315 320 Longitud [ ]
EOF- empirical orthogonal function The EOF was calculated considering 2m temperature They repesent 48% and 17% of variability EOF1 EOF2 0.2 0.2 0.1 0.1 0.0 0.0 0.1 0.1 0.2 0.2 295 300 305 310 315 320 Longitud [ ] 295 300 305 310 315 320 Longitud [ ] EOF 1: temperature anomaly that leads to atmospheric (in)stability
EOF- empirical orthogonal function The EOF was calculated considering 2m temperature They repesent 48% and 17% of variability EOF1 EOF2 0.2 0.2 0.1 0.1 0.0 0.0 0.1 0.1 0.2 0.2 295 300 305 310 315 320 Longitud [ ] 295 300 305 310 315 320 Longitud [ ] EOF 1: temperature anomaly that leads to atmospheric (in)stability EOF 2: temperature gradient associated with frontal activity
EOF- empirical orthogonal function
EOF- empirical orthogonal function We separated into different groups, considering each s extreme day value in First and Second Principal component(cp)
EOF- empirical orthogonal function We separated into different groups, considering each s extreme day value in First and Second Principal component(cp) 60 20 0 20 40 20 10 0 10 20 30 PC1 PC2 clúster Rojo clúster azul clúster violeta 1 and 2 sd
Red group (PC1 +, PC2 +)
Red group (PC1 +, PC2 +) EOF1 EOF2 0.2 0.2 0.1 0.1 0.0 0.0 0.1 0.1 0.2 0.2 295 300 305 310 315 320 Longitud [ ] 295 300 305 310 315 320 Longitud [ ] Atmospheric instability + Frontal activity
Red group (PC1 +, PC2 +) 2 metre temperature anomaly
Red group (PC1 +, PC2 +) 2 metre temperature anomaly Anom P90_Grupo7, día 0, T2m Anom P90_Grupo7, día 1, T2m Anom P90_Grupo7, día 2, T2m 15 15 15 20 20 20 25 25 25 290 300 310 320 290 300 310 320 290 300 310 320 Longitud [ ] Figure 1: Day 0, Day -1, Day -2 Longitud Longitud [ ] [ ] Stationary positive temperature anomaly generating atmospheric instability
Red group (PC1 +, PC2 +) 1000 hpa geopotential anomaly
Red group (PC1 +, PC2 +) 1000 hpa geopotential anomaly Anomalía de Geopotencial, 1000hPa, día 0 Anomalía de Geopotencial, 1000hPa, día 1 Anomalía de Geopotencial, 1000hPa, día 2 15 15 15 20 20 20 25 25 25 280 290 300 310 320 280 290 300 310 320 280 290 300 310 320 Longitud [ ] Figure 2: Day 0, Day -1, Day -2 Longitud [ ] Longitud [ ] Surface low pressure approaching, and reaches Uruguay the day 0
Red group (PC1 +, PC2 +) Frontal Index anomaly
Red group (PC1 +, PC2 +) Frontal Index anomaly Solman & Orlanski, 2010 : T 850 x ξ 850 (1) Anomalía de IF, día 0 Anomalía de IF, día 1 Anomalía de IF, día 2 15 15 15 20 20 20 25 25 25 280 290 300 310 320 280 290 300 310 320 280 290 300 310 320 Longitud [ ] Figure 3: Day 0, Day -1, Day -2 Longitud [ ] Longitud [ ] Cold front approaching from the south
Red group (PC1 +, PC2 +) Latent heat anomaly, OLR anomaly
Red group (PC1 +, PC2 +) Latent heat anomaly, OLR anomaly Anom P90_Grupo7, día 0,Latent Flux Anom P90, día +1, OLR 15 15 20 20 25 25 290 300 310 320 280 290 300 310 320 Longitud [ ] longitud [ ] Figure 4: Day 0, Day 0 Negative latent flux anomaly, indicating evaporation Negative OLR, indicating rainfall in all the country
Red group (PC1 +, PC2 +) Why does it rain?
Red group (PC1 +, PC2 +) Why does it rain? Atmospheric instability due to positive temperature anomaly
Red group (PC1 +, PC2 +) Why does it rain? Atmospheric instability due to positive temperature anomaly Surface low pressure generating upward movement and condensation
Red group (PC1 +, PC2 +) Why does it rain? Atmospheric instability due to positive temperature anomaly Surface low pressure generating upward movement and condensation Even more humidity due to evaporation
Red group (PC1 +, PC2 +) Why does it rain? Atmospheric instability due to positive temperature anomaly Surface low pressure generating upward movement and condensation Even more humidity due to evaporation Frontal activity triggers the extreme rainfall event
Blue group (PC1 +, PC2 -)
Blue group (PC1 +, PC2 -) EOF1 EOF2 0.2 0.2 0.1 0.1 0.0 0.0 0.1 0.1 0.2 0.2 295 300 305 310 315 320 295 300 305 310 315 320 Longitud [ ] Atmospheric instability Longitud [ ]
Blue group (PC1 +, PC2 -) 200 hpa geopotential height anomaly
Blue group (PC1 +, PC2 -) 200 hpa geopotential height anomaly Anomalía de Geopotencial, 200hPa, día 0 Anomalía de Geopotencial, 200hPa, día 1 Anomalía de Geopotencial, 200hPa, día 2 0 0 0 20 20 20 60 60 60 80 80 80 200 250 300 350 200 250 300 350 200 250 300 350 Longitud [ ] Figure 5: Day 0, Day -1, Day -2 Longitud Longitud [ ] [ ] Stationary wave
Blue group (PC1 +, PC2 -) 1000 hpa geopotential height anomaly
Blue group (PC1 +, PC2 -) 1000 hpa geopotential height anomaly Anomalía de Geopotencial, 1000hPa, día 0 Anomalía de Geopotencial, 1000hPa, día 1 Anomalía de Geopotencial, 1000hPa, día 2 15 15 15 20 20 20 25 25 25 280 290 300 310 320 280 290 300 310 320 280 290 300 310 320 Longitud [ ] Figure 6: Day 0, Day -1, Day -2 Longitud [ ] Longitud [ ] Blocking situation, caused by the stationary wave generating clear skies and preventing cold fronts from reaching the area
Blue group (PC1 +, PC2 -) 2 metre temperature anomaly
Blue group (PC1 +, PC2 -) 2 metre temperature anomaly Anom P90_Grupo8, día 0, T2m Anom P90_Grupo8, día 1, T2m Anom P90_Grupo8, día 2, T2m 15 15 15 20 20 20 25 25 25 290 300 310 320 290 300 310 320 290 300 310 320 Longitud [ ] Figure 7: Day 0, Day -1, Day -2 Longitud Longitud [ ] [ ] Positive temperature anomaly intensifying in the west of Uruguay
Blue group (PC1 +, PC2 -) Heat flux anomaly
Blue group (PC1 +, PC2 -) Heat flux anomaly Anom P90_Grupo8, día 0,Latent Flux Anom P90_Grupo8, día 1,Latent Flux Anom P90_Grupo8, día 2,Latent Flux 15 15 15 20 20 20 25 25 25 290 300 310 320 290 300 310 320 290 300 310 320 Longitud [ ] Figure 8: Day 0, Day -1, Day -2 Longitud Longitud [ ] [ ] Heat transfer to the atmosphere, due to the clear sky, destabilizing the boundary layer
Blue group (PC1 +, PC2 -) OLR anomaly
Blue group (PC1 +, PC2 -) OLR anomaly Anom P90, día +1, OLR Anom P90, día 0, OLR 15 15 20 20 25 25 280 290 300 310 320 280 290 300 310 320 longitud [ ] longitud [ ] Figure 9: Day 0, Day -1 Negative OLR anomaly in the west that approaches and instensifies
Blue group (PC1 +, PC2 -) Why does it rain?
Blue group (PC1 +, PC2 -) Why does it rain? Stationary wave associated with blocking episode
Blue group (PC1 +, PC2 -) Why does it rain? Stationary wave associated with blocking episode High surface pressure favouring positive temperature anomalies and boundary layer destabilization
Blue group (PC1 +, PC2 -) Why does it rain? Stationary wave associated with blocking episode High surface pressure favouring positive temperature anomalies and boundary layer destabilization Positive temperature anomalies in the west of Uruguay, generating atmospheric instability
Blue group (PC1 +, PC2 -) Why does it rain? Stationary wave associated with blocking episode High surface pressure favouring positive temperature anomalies and boundary layer destabilization Positive temperature anomalies in the west of Uruguay, generating atmospheric instability Deep convective activity in the west of Uruguay that reaches the area
Violet group (PC1 -, PC2 +)
Violet group (PC1 -, PC2 +) EOF1 EOF2 0.2 0.2 0.1 0.1 0.0 0.0 0.1 0.1 0.2 0.2 295 300 305 310 315 320 Longitud [ ] 295 300 305 310 315 320 Longitud [ ] Frontal activity
Violet group (PC1 -, PC2 +) 200 hpa geopotential divergence
Violet group (PC1 -, PC2 +) 200 hpa geopotential divergence 200hPa P90_Grupo9_B, Anom Div, Día 0 200hPa P90_Grupo9_B, Anom Div, Día 1 200hPa P90_Grupo9_B, Anom Div, Día 2 15 15 15 20 20 20 25 25 25 280 290 300 310 320 280 290 300 310 320 280 290 300 310 320 Longitud [ ] Figure 10: Day 0, Day -1, Day -2 Longitud [ ] Longitud [ ] Positive divergence favouring upward movements
Violet group (PC1 -, PC2 +) 1000 hpa geopotential height anomaly
Violet group (PC1 -, PC2 +) 1000 hpa geopotential height anomaly Anomalía de Geopotencial, 1000hPa, día 0 Anomalía de Geopotencial, 1000hPa, día 1 Anomalía de Geopotencial, 1000hPa, día 2 15 15 15 20 20 20 25 25 25 280 290 300 310 320 280 290 300 310 320 280 290 300 310 320 Longitud [ ] Figure 11: Day 0, Day -1, Day -2 Longitud [ ] Longitud [ ] Low pressure favouring upward movement
Violet group (PC1 -, PC2 +) 850 hpa divergence
Violet group (PC1 -, PC2 +) 850 hpa divergence 850hPa P90_Grupo9_B, Anom Div, Día 0 850hPa P90_Grupo9_B, Anom Div, Día 1 850hPa P90_Grupo9_B, Anom Div, Día 2 15 15 15 20 20 20 25 25 25 280 290 300 310 320 280 290 300 310 320 280 290 300 310 320 Longitud [ ] Figure 12: Day 0, Day -1, Day -2 Longitud [ ] Longitud [ ] Negative divergence, indicating humidity advection
Violet group (PC1 -, PC2 +) OLR anomaly
Violet group (PC1 -, PC2 +) OLR anomaly Anom P90, día +1, OLR Anom P90, día 0, OLR Anom P90, día 1, OLR 15 15 15 20 20 20 25 25 25 280 290 300 310 320 280 290 300 310 320 280 290 300 310 320 longitud [ ] Figure 13: Day 0, Day -1, Day -2 longitud [ ] longitud [ ] Negative OLR anomaly, indicating rainfall
Violet group (PC1 -, PC2 +) Why does it rain?
Violet group (PC1 -, PC2 +) Why does it rain? 200 hpa divergence favouring upward movements
Violet group (PC1 -, PC2 +) Why does it rain? 200 hpa divergence favouring upward movements Low surface pressure favouring upward movements
Violet group (PC1 -, PC2 +) Why does it rain? 200 hpa divergence favouring upward movements Low surface pressure favouring upward movements Humidity advection
Conclusions We clasified the extreme rainfall events in 3 categories according to their 2 metre temperature configurations
Conclusions We clasified the extreme rainfall events in 3 categories according to their 2 metre temperature configurations Red extremes are characterized by a combination of atmospheric instability, evaporation and frontal activity in Uruguay
Conclusions We clasified the extreme rainfall events in 3 categories according to their 2 metre temperature configurations Red extremes are characterized by a combination of atmospheric instability, evaporation and frontal activity in Uruguay Blue extremes are characterized by a instable boundary layer in Uruguay and deep convective activity approaching from the west
Conclusions We clasified the extreme rainfall events in 3 categories according to their 2 metre temperature configurations Red extremes are characterized by a combination of atmospheric instability, evaporation and frontal activity in Uruguay Blue extremes are characterized by a instable boundary layer in Uruguay and deep convective activity approaching from the west Violet extremes are characterized by a combination of low surface pressure and humidity advection
Final conclusion We were able to achieve the objective
Final conclusion We were able to achieve the objective Questions? Suggestions?