1. New CoHA Product Access Page & Representativeness Analysis
7 Feb 2007

2. New Query Tool on CoHA web
In beta testing…
Select CoHA results using this query page
Select site or all sites within a state

3. Example
Selecting New Mexico gives you all of the CoHA products for that state for all 9 class I areas

4. Representativeness Assessment
Assessment of the representativeness of 2002 worst case days compared to a five year base period (2000 to 2004)
Based on CoHA HYSPLIT runs with EDAS and FNL
For each IMPROVE site in the WRAP region
Generated two maps at each site:
Difference between 2002 and the 5-year worst 20% residence time
Ratio of 2002 over the 5-year worst 20% residence time

5. What Contributes to Variations?
Differences in annual residence time during the worst case days may be due to:
drought
El Nino, La Nina
year to year variations in wildfires intensity, number and locations
local and regional high wind dust events
Asian dust events (one significant one in 2002)
stagnation events as represented by high sulfate, organics and nitrate

6. Meteorological Variations
2002 was a moderate El Niño year
Summer of 2002 was hot and dry compared to climate
Surface temperature anomaly map showing anomalies of around 1.5 degrees C through most of WRAP region

7. Variability in Smoke PMF Smoke Factor for 2002
Contribution of PMF smoke factor to PM2.5 in µg/m3

8. Fires in 2002

9. Variations in Dust Concentrations
Comparison of dust (fine dust + coarse mass) on 2002 compared to mean
Based on DRI’s Causes of Dust Analysis

10. Variations in # of Dust Days
Comparison of the number of worst case dust days in 2002 compared to mean
Based on DRI’s Causes of Dust Analysis

11. Click on this icon to access 2002
Representativeness maps

12. Example:
Agua Tibia
Difference map
Ratio map

13. Interpretations
Computing a difference map of 2002 RT versus 5-year RT gives positive numbers for higher than average frequencies from those areas and negative for lower than average frequencies
Ratio of 2002 to 5-year RT gives "enhancement" factor when passing over those areas, but no information about frequency

14. Gila Wilderness Example
Difference
Ratio

15. THANKS!