Interhemispheric Transport

of Pyrocumulonimbus (pyroCb)

Smoke

in the Stratosphere Mike Fromm

Naval Research Lab

WORKSHOP ON DYNAMICS, TRANSPORT AND CHEMISTRY OF THE UTLS ASIAN MONSOON

7-11 March 2016, Boulder, CO

Outline

* Extensive meridional plume transport

in the literature

* The remarkable 1998 Boreal pyroCb season

* Analyze LOTS of 1998 aerosol profiles,

from early to late,

from north to south

In Conclusion…

• PyroCbs inject smoke (and other stuff) into the UTLS.

– Even above 380 K

• Single pyroCbs can pollute an entire hemisphere.

– Tropical to polar latitudes

• LS smoke from a 65°N pyroCb in 1998 crossed the Equator.

• In 1998 the tropical LS was filled with boreal smoke.

Tropical impact from extratropical pyroCb has precedent…

From Livesey et al., 2004 (JGR) From Jost et al., 2004 (GRL)

From Siddaway and Petelina, 2011 (JGR)

1992

Idaho

2002

Manitoba

2009

Victoria

The Chisholm (Alberta) pyroCb plume

29 May 2001

SeaWiFS True Color

Fromm et al., JGR, 2008)

Mauna Loa (19.5°N) lidars, summer 2001

No layers “Strong” layers 2nd half of June

More layers, less “strong”

Sporadic layers in early Aug

JPL PI: Stuart McDermid

NOAA PI: John Barnes

vs. Theta

380 K

Chisholm plume on 11 June 2001

Three consecutive SAGE II strat layers over Asia and Pacific.

Six consecutive POAM layers farther north.

POAM

SAGE Dots: smoke layers

Pluses: no layer

Gadanki (13.5°N), India

- lidar

- aerosol layer 17.5 km

- 21 June 2001 Back trajectory

to 10 June

Thanks to P. Kulkarni

The Amazing Fire Season of 1998 (Fromm et al., 2000, GRL)

Mid-July

The Amazing Fire Season of 1998 (Fromm et al., 2000, GRL)

May June July Aug Sep Oct

The Amazing Fire Season of 1998 (Fromm et al., 2000, GRL)

POAM III

Zonal Avg. AOD

SeaWiFS True Color Norman Wells PyroCb Plume

4 August 1998 Far Northern Canada

pyroCb

So how far south did the 1998 pyroCb smoke go?

We’ll invoke Mauna Loa lidar, then SAGE II

JPL lidar* 355 nm backscatter ratio profiles

September – October 1998 Mauna Loa (19ºN)

* Stuart McDermid, PI

September – October 1998 Mauna Loa (19ºN)

JPL lidar* 355 nm backscatter ratio profiles

* Stuart McDermid, PI

SUMMARY

• How unusual is cross-Equator UTLS transport from

extratropical source?

* Black Saturday and Norman Wells stratospheric plumes

detectable for at least 4 months.

* Chisholm: 3 months.

* Northern Fire season: May-September

* Northern Summer Monsoon season: June-September

* Counting pyroCbs since 2013. More than 30/yr.

* Pollutants outside the AM may have a different source.

• PyroCbs inject smoke (and other stuff) into the UTLS.

– Even above 380 K

• Single pyroCbs can pollute an entire hemisphere.

– Tropical to polar latitudes

• LS smoke from a 65°N pyroCb in 1998 crossed the Equator.

• In 1998 the tropical LS was filled with boreal smoke.