Table 1.
Literature review of previous studies on estimated impacts of (upper) emissions from Asia and (lower) stratospheric intrusion.
| Time period | Estimated impacts | Location | Method | Reference |
|---|---|---|---|---|
| Emissions from Asia | ||||
| April 2001 | 1ppbv (monthly mean), up to 2.5ppbv (daily mean) |
western US | model (process analysis) | Wang et al. (2009) |
| April–May 2002 | 10ppbv increase from April to May 1984 |
5 west coast US sites | observation (linear regression) | Jaffe et al. (2003) |
| April–May 2006 | 5–7ppbv (17 April–15 May 2006; INTEX-B) |
western North America | model (zero-outa) | Zhang et al. (2008) |
| increase the above influence by 1–2ppbv | western North America | model (doubling NOx emissions from eastern Asia) | Zhang et al. (2008) | |
| 2–5ppbv (17 April–15 May 2006; INTEX-B) |
eastern North America | model (zero-outa) | Zhang et al. (2008) | |
| April–June 2010 | 2–6ppbv increase from April to June 1985 |
western US | model (tripling Asian emissions from 1985) | Jacob et al. (1999) |
| 1–3ppbv increase from April to June 1985 |
eastern US | model (tripling Asian emissions from 1985) | Jacob et al. (1999) | |
| May–June 2010 | 8–15ppbv on specific events | high-elevation regions | model (zero-outa) | Lin et al. (2012a) |
| April–June 2010 | 4.7±2.4ppbv (3-month mean) | 15 high-elevation western US sites | model (zero-outa) | Lin et al. (2012b) |
| Stratospheric intrusion | ||||
| March–October 2001 | below 20ppbv | US | tagged O3b | Fiore et al. (2003) |
| April–May 1990–2012 | 10–25ppbv | 22 high-elevation western US sites | tropopause tracerc | Lin et al. (2015) |
| April–June 2010 | 22.3±11.5ppbv (3-month mean) | 15 high-elevation western US sites | tropopause tracerc | Lin et al. (2012b) |
a
This estimates the impact from the difference between the standard simulation and a simulation with eastern Asian anthropogenic sources shut off.
b
This tagged method divides simulated O3 into individual O3 tracer to track O3 produced in different region.
c
This tracer method accounts for STT contribution to O3 using e90 tracer, which differentiates tropospheric air mass based on the globally uniform surface source and 90d folding lifetime; both have been spun up for 3 years.