Impacts of BC from fire emission on air quality ---- case study in 2010

Benpei Cao

04/25/13

Introduction

• Black carbon (BC) is mainly emitted from incomplete burning processes of fossil fuel and biomass;

• BC is the most efficient light-absorbing fraction of aerosols. The warming effect of BC is surpassed only by CO2;

• BC has a short atmospheric residence time of 2-3 weeks, which means its concentration is strongly influenced by episodic events and meteorology;

• Wildfire is identified as an important source for BC. The fire activity is increasing due to climate change.

Wildfire in Russia

Moscow

Peak fire:1-10 August MODIS fire counts (orange) & FRP greater than 200 MW (blue)Source:

AOD: 25-31 Jul MODIS Terra AOD

>Several hundred wildfires broke out across western Russia>Starting from late July, lasting until early September>The worst on record to that time. Roughly $15 billion USD damages

Wildfire in Southern America

Brazil

MODIS Terra AOD: 15-31 Aug 2010Anomalies of vegetation covering during Jul-Sep 2010

Source: World resources report

Cause of Fire (Russian case)

>Historically hot summer and drought>High coverage of forests, ~30% world-wideforests are in Russia

Source:

Model Simulation

CAM-chem

Default input Modified (BC) emission input

GFEDv3 fire emission

Questions to answer:>How does BC emission affect the meteorology and air quality?>What feedback BC emission could have on wildfire?

Coupled chemistry-climate model, incorporating the MOZART chemical mechanism in CAM (Community Atmosphere Model)

AOD: Satellite vs. Default-run

Satellite July Model July

Satellite Aug Model Aug

AOD: Default-run vs. Modified-run

Default July Modified July

Default Aug Modified Aug

BC Monthly Mean

Default run

Modified run

Black Carbon: August Mean (µg/m3)

>We lost BC over Asia>Got higher BC in South America and Africa

MODIS: Brazil August 17

Why we didn’t get BC in Russia?

GFED v3 product we used to modify the emission didn’t show BC enhancement over Russia!

Aug fire emission: gC/m2/month

We are not alone

Source: An extreme air pollution episode in the Moscow region, ACP

What to do next:

BC Radiation Meteorology Air Quality

Fire Feedback>Temperature>Precipitation>Wind Speed>PBL heightetc

Thank You!