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Table 1

Constraints to define transport patterns, abbreviations of the transport patterns, and the estimated occurrence frequencies in spring (April and May), summer (June, July, and August), and fall (September and October). DOI: https://doi.org/10.1525/elementa.194.t1

Transport PatternsAbbrev.Constraint*Occurrence Frequency ** %
SpringSummerFall

 
North American flow NA RT over North America in 0–5 km a.s.l. greater than 50% for at least 1 day 40 30 32 
NA affected by anthropogenic emissions NA-anthro North America anthropogenic FLEXPART_CO contribution greater than 15 ppbv, fire<15 ppbv 16 15 13 
NA-anthro lifted during transport NA-anthro-lifted 1. Same as NA-anthro 4.0 2.7 2.5 
  2. RT in a vertical range 0–2.5 km reduced 30% within 24 hour during 0–15 days upwind    
NA-anthro within or close to MBL NA-anthro-low 1. Same as NA-anthro 3.1 1.7 <1.0 
  2. RT within 0–2.5 km greater than 40% from 0–5 days upwind    
NA-anthro quick transport NA-anthro-young 1. Same as NA-anthro 6.7 4.3 4.0 
  2. FLEXPART_CO age from anthropogenic emissions less than 7 days    
NA-anthro aged transport NA-anthro-aged 1. Same as NA-anthro 6.2 5.3 4.5 
  2. FLEXPART_CO age from anthropogenic emissions greater than 10 days    
Wildfire affected Fire Wildfire FLEXPART_CO contribution greater than 15 ppbv, Anthropogenic <15 ppbv <1.0 7.3 2.6 
Fire quick transport Fire-young 1. Same as Fire <1.0 2.5 1.0 
  2. FLEXPART_CO age from wildfire emissions less than 7 days    
Fire slow transport Fire-aged 1. Same as Fire <1.0 3.0 1.3 
  2. FLEXPART_CO age from wildfire emissions greater than 10 days    
European flow EU RT over Europe greater than 50% for at least 1 day 1.8 <1.0 <1.0 
African flow AF RT over Afreica greater than 50% for at least 1 day <1.0 <1.0 2.6 
North Atlantic free troposphere background NATL RT over North Atlantic in 0–5 km a.s.l. greater than 70% through 0–10 days upwind 17 19 8.3 
Downward mixing from UTLS Upper RT less than 40% in 0–5 km through 2–12 days upwind 2.1 2.3 4.1 
Upslope flow Upslope Simulated PBL height greater than altitude of Pico or DSL less than PBL height 24 13 15 
Transport PatternsAbbrev.Constraint*Occurrence Frequency ** %
SpringSummerFall

 
North American flow NA RT over North America in 0–5 km a.s.l. greater than 50% for at least 1 day 40 30 32 
NA affected by anthropogenic emissions NA-anthro North America anthropogenic FLEXPART_CO contribution greater than 15 ppbv, fire<15 ppbv 16 15 13 
NA-anthro lifted during transport NA-anthro-lifted 1. Same as NA-anthro 4.0 2.7 2.5 
  2. RT in a vertical range 0–2.5 km reduced 30% within 24 hour during 0–15 days upwind    
NA-anthro within or close to MBL NA-anthro-low 1. Same as NA-anthro 3.1 1.7 <1.0 
  2. RT within 0–2.5 km greater than 40% from 0–5 days upwind    
NA-anthro quick transport NA-anthro-young 1. Same as NA-anthro 6.7 4.3 4.0 
  2. FLEXPART_CO age from anthropogenic emissions less than 7 days    
NA-anthro aged transport NA-anthro-aged 1. Same as NA-anthro 6.2 5.3 4.5 
  2. FLEXPART_CO age from anthropogenic emissions greater than 10 days    
Wildfire affected Fire Wildfire FLEXPART_CO contribution greater than 15 ppbv, Anthropogenic <15 ppbv <1.0 7.3 2.6 
Fire quick transport Fire-young 1. Same as Fire <1.0 2.5 1.0 
  2. FLEXPART_CO age from wildfire emissions less than 7 days    
Fire slow transport Fire-aged 1. Same as Fire <1.0 3.0 1.3 
  2. FLEXPART_CO age from wildfire emissions greater than 10 days    
European flow EU RT over Europe greater than 50% for at least 1 day 1.8 <1.0 <1.0 
African flow AF RT over Afreica greater than 50% for at least 1 day <1.0 <1.0 2.6 
North Atlantic free troposphere background NATL RT over North Atlantic in 0–5 km a.s.l. greater than 70% through 0–10 days upwind 17 19 8.3 
Downward mixing from UTLS Upper RT less than 40% in 0–5 km through 2–12 days upwind 2.1 2.3 4.1 
Upslope flow Upslope Simulated PBL height greater than altitude of Pico or DSL less than PBL height 24 13 15 

* RT = residence time of FLEXPART retroplumes.

** Spring = April–May; Summer = June–August; Fall = September–October Unclassified time percentages are 22%, 39%, and 40 % for spring, summer, and fall, respectively.

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