FASTNET Report: 0409FebMystHaze

Mystery Winter Haze:

Natural? Nitrate/Sulfate? Stagnation?

Contributed by the FASNET Community, Sep. 2004

Correspondence to R Husar , R Poirot

Coordination Support by

Inter-RPO WG Fast Aerosol Sensing Tools for Natural Event Tracking, FASTNETNSF Collaboration Support for Aerosol Event Analysis

NASA REASON CoopEPA -OAQPS

AIRNOW PM25 - February

Secondary MP25 Peak in February-March

• The AIRNOW PM25 data are available real-time for 300+ stations since July 2002.• The 30-day smoothing of the average hourly data shows the Eastern US PM25 seasonality• The seasonal pattern shows the summertime sulfate peak and a second Feb/Mar peak• The the existence, characteristics and origin of this regional peak is not known• The objective of effort is to characterize this ‘mysterious’ phenomenon over the EUS• The approach is to seek out the community as a resource for collaborative analysis

Sulfate-driven Jul-Aug peak

Feb-Mar peak, of unknown

origin

Seasonal PM25 by Region

The 30-day smoothing average shows the seasonality by region

The Feb/Mar PM25 peak is evident for the Northeast, Great Lakes and Great Plains

This secondary peak is absent in the South and West

PM25 Monthly Concentration

• Monthly average PM25 are shown as circle and contour (Blue: 0; Red: 25 g/m3)• The Feb/Mar peak is clearly evident in the Upper Midwest region

JAN FEB MAR APR

MAY JUN JUL AUG

SEP OCT NOV DEC

Blue: 0

Red: 25

AIRNOW Jul 02-Sep 04

FRM PM25 Monthly Concentration

• Monthly average FRM PM25 are shown as circle and contour (Blue: 0; Red: 25 g/m3)• The Feb/Mar peak is clearly evident in the Midwest region; also in January• Hence, there is some deviation in peak location and time among the networks

JAN FEB MAR APR

MAY JUN JUL AUG

SEP OCT NOV DEC

EPA AIRS 1999-2002

February 2005 ‘Nitrate’ Event

• AIRNow shows the high surface PM2.5 concnetration during the January 2005 event. • This PM2.5 episode in Minneapolis made it to the CNN nightly news)

050126 050128 050129

050130 050131 050201 050202

050127

Satellite Data: POLDER Aerosol Polarization Index

• The (short-lived, Nov 96-Jun97) POLDER satellite sensor measured the of aerosol polarization, which is sensitive to fine particles, < 1 m

• For Jan-Mar the data show a strong aerosol signal over the Upper Midwest and adjacent Canada

• Skeptics have attributed the ‘anomalous’ aerosol zone to interferences such as snowy ground reflectance

• In light of the recent ground-based PM25 monitoring data, the early (1997) POLDER results deserve full attention

Dauze et. al, 2001

Satellite Data: MISR Aerosol Optical Thickness

• The MISR sensor on Terra satellite performs multi-angle (60-150 deg?) scans for aerosol retrieval• Four years of AOT data over land (2001-04) provide further evidence of the Jan-Mar aerosol peak• Interestingly, both POLDER and MISR show the aerosol patch extending deep into Central Canada

Where do we go from here?

• Is it real ???

• Natural? Nitrate/Sulfate? Stagnation?