Exploring Oceanic Source Regions And Moisture Transport for Extreme - PowerPoint PPT Presentation

Exploring Oceanic Source Regions And Moisture Transport for Extreme Floods: Ohio River Basin J. Nakamura 1 , Y. Kushnir 1 ,R. Seager 1 ; A. W. Robertson 3 , M. Lu 2,4 , U. Lall 2,3,4 1. Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, United States. 2. Earth and Environmental Engineering, Columbia University, NY, NY, United States. 3. International Research Institute for Climate and Society, Palisades, NY, United States. 4. Columbia Water Center, Columbia University, NY, NY, United States. I nterna&onal ¡R esearch ¡I ns&tute ¡ for ¡C limate ¡ & ¡S ociety ¡ C OLUMBIA ¡ W ATER ¡C ENTER , ¡LDEO-­‑CICAR ¡ Global ¡Flood ¡Ini<a<ve ¡

Key Points  Extreme Floods in Mid-Latitudes  Antecedent Soil Moisture (past rain) AND persistent, rain event with basin scale coverage  Tropical Moisture Exports associated with strong and persistent circulation anomalies ?=? Atmospheric Rivers  Synoptic weather modulated by larger scale dynamics?  Diagnosis of 20 >10 year flood events in the Ohio River Basin + Euro events with tropical Atlantic Moisture sources  Examine associated circulation parameters  Event attributes (Apr2011 Ohio R, Jan 1995 France-Germany, 8 events UK)  Composites over 20 events for Ohio River Basin (MAM)  20th Century Reanalysis V2 data, MERRA, Knippertz Wernli TME, USGS  Evidence of consistent patterns and organization across events suggesting potential predictability – FLOODS are DETERMINED and not just RANDOM  Circulation clusters/hidden states relate to MJO/ENSO – potential medium to long range predictability?

Precipitation Anomaly a) MAM 20 Event Composite Days -9 to 0 48 o N 48 o N 10 8 44 o N 44 o N 6 4 40 o N 40 o N Precipitation anomaly in mm 2 0 day -1 of a) average of 20 36 o N 36 o N � 2 historical, 20th century floods � 4 32 o N 32 o N � 6 in large river basins in the � 8 Ohio Valley (basin outlines in 28 o N 28 o N � 10 104 o W 104 o W 96 o W 96 o W 88 o W 88 o W 80 o W 80 o W 72 o W 72 o W hot pink) and b) average of b) 18-27 Apr 2011 18-27 April 2011. 20 48 o N 48 o N 15 44 o N 44 o N 10 5 40 o N 40 o N 0 Large Scale events 36 o N 36 o N � 5 � 10 32 o N 32 o N � 15 28 o N 28 o N � 20 Nakamura et al, 2012 104 o W 104 o W 96 o W 96 o W 88 o W 88 o W 80 o W 80 o W 72 o W 72 o W

Floods exceeding the 10 year flood across Ohio River sub-basins Robertson et al, 2012

Surface Air Temp Precipitation Anomaly time series of variables averaged over the Ohio River basin (a-d), between 100°W and 90°W 700mb vertical velocity Precipitable Water and 28°N to 42°N (e -g), from days -10 to day 2 (flood is day 0). 20-event composite mean (solid grey) median (dashed grey) 700mb High-low height Meridional Moisture flux 25 th to 75 th percentile spread (shaded grey) April 2011 event (black). Integrated Moisture Convergence Nakamura et al, 2012

Surface-600 mb Moisture Flux and Convergence a) MAM 20 Event Composite Days -9 to 0 0.15 0.2 200 kg m/s 80 kg m/s 72 o N 72 o N 0.15 0.1 60 o N 60 o N 0.1 0.05 0.05 48 o N 48 o N 0 0 36 o N 36 o N � 0.05 � 0.05 � 0.1 24 o N 24 o N � 0.1 � 0.15 12 o N 12 o N � 0.2 � 0.15 150 o W 120 o W 90 o W 60 o W 30 o W 150 o W 120 o W 90 o W 60 o W 30 o W Full field Anomaly b) 18-27 Apr 2011 0.15 0.2 200 kg m/s 80 kg m/s 72 o N 72 o N 0.15 0.1 60 o N 60 o N 0.1 0.05 0.05 48 o N 48 o N 0 0 36 o N 36 o N � 0.05 � 0.05 � 0.1 24 o N 24 o N � 0.1 � 0.15 12 o N 12 o N � 0.2 � 0.15 150 o W 120 o W 90 o W 60 o W 30 o W 150 o W 120 o W 90 o W 60 o W 30 o W (a) Vertically integrated 600 mb - surface moisture flux in kg m s -1 (strongest 20 percent of values shown as arrows) and moisture convergence in gm -2 s -1 (contours) for drainage basins (size > 10 3 km 2 ) within the Ohio Valley averaged over the nine days leading to the 10-year flood. Nakamura et al, 2012 Large-scale anti-cyclonic moisture flow & convergence (Bermuda High)

Surface-600 mb Integrated Meridional Wind (kgm − 1 s − 1 ) (contours) and Moisture Transport (gms − 1 ) (colors) at 25 N, Days -10 to 2 a) MAM 20 Event Composite Moisture channeling 1 0 0 2000 topography [m] between the Rocky and -1 Appalachian mountains Days Days Rockies -5 -5 1000 Hovmoller plot Pacific Ocean Atlantic Ocean (600 mb-surface) -10 -10 meridional wind 0 150 ˚ W 150 ˚ W 150 ˚ W 120 ˚ W 120 ˚ W 120 ˚ W 90 ˚ W 90 ˚ W 90 ˚ W 60 ˚ W 60 ˚ W 60 ˚ W 30 ˚ W 30 ˚ W 30 ˚ W Longitude Longitude Longitude (contour) and moisture transport (colors) -200 -160 -120 -80 -40 0 40 80 120 160 200 Integrated Meridional Moisture Transport [gms^-1] b) 27 Apr 2011 25N -1 -2 -1 1 2 0 0 2000 topography [m] -3 -2 2 1 1 Days Days -3 3 -5 -5 -1 1 2 -1 1000 Rockies -2 -1 1 1 Pacific Ocean Atlantic Ocean -1 1 2 1 -10 -10 0 150 ˚ W 150 ˚ W 150 ˚ W 120 ˚ W 120 ˚ W 120 ˚ W 90 ˚ W 90 ˚ W 90 ˚ W 60 ˚ W 60 ˚ W 60 ˚ W 30 ˚ W 30 ˚ W 30 ˚ W Longitude Longitude Longitude Nakamura et al, 2012 -400 -300 -200 -100 0 100 200 300 400 Integrated Meridional Moisture Transport [gms^-1]

Surface-600 mb Integrated Meridional Wind (kgm − 1 s − 1 ) (contours) and Moisture Transport (gms − 1 ) (colors) at 35 N, Days -10 to 2 a) MAM 20 Event Composite Moisture channeling -2 0 0 2000 topography [m] 1 between the Rocky and -1 2 1 Appalachians Days Days Appalachian mountains Rockies -1 -5 -5 1000 Pacific Ocean Atlantic Ocean Hovmoller plot 1 1 (600 mb-surface) 1 -10 -10 0 meridional wind 150 ˚ W 150 ˚ W 150 ˚ W 120 ˚ W 120 ˚ W 120 ˚ W 90 ˚ W 90 ˚ W 90 ˚ W 60 ˚ W 60 ˚ W 60 ˚ W 30 ˚ W 30 ˚ W 30 ˚ W Longitude Longitude Longitude (contour) and moisture -200 -160 -120 -80 -40 0 40 80 120 160 200 transport (colors) Integrated Meridional Moisture Transport [gms^-1] b) 27 Apr 2011 35N 1 -1 -1 5 3 -4 0 0 2000 topography [m] -1 1 -2 -2 2 -5 1 -3 Appalachians -2 Days Days 1 2 -3 -3 Rockies -5 -5 1000 1 Pacific Ocean 1 Atlantic Ocean -1 -2 1 3 -1 -4 2 -1 1 2 4 2 -10 -10 -5 0 150 ˚ W 150 ˚ W 150 ˚ W 120 ˚ W 120 ˚ W 120 ˚ W 90 ˚ W 90 ˚ W 90 ˚ W 60 ˚ W 60 ˚ W 60 ˚ W 30 ˚ W 30 ˚ W 30 ˚ W Longitude Longitude Longitude Nakamura et al, 2012 -400 -300 -200 -100 0 100 200 300 400 Integrated Meridional Moisture Transport [gms^-1]

Moisture Anomaly*Circulation Anomaly field is dominated by the advection of the moisture by the anomalous circulation Circulation Anomaly*Moisture 20 event Composite (left) 2011 event (right) Moisture Anomaly*Circulation Anomaly Nakamura et al, 2012