Talk:Evidence for Flagging Exceptional Events

NFrank: Initial Feedback -- Rhusar 10:22, 24 April 2008 (EDT)

I have started to study the "report". There is a lot of great stuff here. (BTW, what happened to your google earth console to show the trajectories and other layers? I thought that format was really neat and added to our understandings.)

There are several aspects of your current report that can benefit from larger community input. In particular, there are a few points which are not currently clear to me. See item (1) below. I hope that you or others can clarify. I also think the conclusions need to be soften particularly for the more borderline exceedances and departures from "normal" and the outline of "affected" areas to be better delineated. Once those points are clearer, we should expose to a larger group.

(1) See the two phrases in blue below: Because of your "question mark," are your speculating or concluding that the trajectories reached Illinois and Minnesota? ... I also don't understand your connection between Ohio to Midlantic transport as basis to discount GA impact on OH. Please clarify :

"On May 24, the high concentration sites stretched from Alabama northward into the Ohio River Valley. The backtrajectories for all sites show a clockwise, anti-cyclonic circulation that brings marine air from the Gulf and Atlantic into the eastern U.S. The western bundle of trajectories, which result in high concentrations at receptor sites from Georgia through Illinois/Minnesota? are all passing through the Georgia fire region. These trajectories provide evidence that the smoke has impacted eastern U.S. sites that stretch all the way up to Minnesota/Illinois. On the other hand, the backtrajectories for the air masses reaching the Ohio River Valley are passing to the mid-atlantic states, well north of the Georgia fire. Therefore, those sites in the Ohio River Valley are not likely to be influenced by the smoke. "

(2) As you mentioned in earlier email, alternative moving medians or other baselines would be helpful.

In this example of this several week event, the 30-day median may itself reflect the influence of the fire. Alternative indicators of "normal" are therefore needed that look to (a) seasonal periods not affected by the event, say from the prior 3 years and (b) different baselines to more confidently distinguish exceptional from normal (e.g. 1 or 2 std deviations above seasonal normals, or even 95th/98th percentiles.)

Rudy, can the selection of normal be easily modified to permit user to consider such alternative indicators?

(3) More specificity is required to identify the boundaries of (and specific monitoring sites in ) the sub-areas for which there would not be an exceedance but for the event. The ones with high and low certainty should be id'd. This is where the alternative baselines could be helpful. It would also be helpful to extend these findings to other days claimed to be affected by the GA fires, and in particular, to isolate those exceedance days and locations with lesser amounts of evidence. The latter can include days without speciation data like May 25 with NE exceedances which is easy to examine using your

Analyst's Console. For these days, to what extend should data and conclusions reached from adjacent days be used, and therefore with more reliance placed on trajectories and perhaps with a higher baseline to represent "normal" . Other recommendations for ways to help reach conclusions are also desired. To help with the latter, we can possibly call upon STI with whom we have a work assignment to evaluate exceptional event days. For example, we can limit that task to those days and locations which have already been proposed by the States as exceptional. Let's see what we can accomplish internally first.