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 Patterns . | Abbrev. . | Constraint* . | Occurrence Frequency ** % . | ||
|---|---|---|---|---|---|
| . | . | . | Spring . | Summer . | Fall . |
| 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 Patterns . | Abbrev. . | Constraint* . | Occurrence Frequency ** % . | ||
|---|---|---|---|---|---|
| . | . | . | Spring . | Summer . | Fall . |
| 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.