Fast and Furious

One of the more interesting aspects of our current inversion is how rapidly the air quality deteriorated.  To illustrate this, check out the two photos below, one taken late Wednesday afternoon, the other Sunday afternoon.

Wednesday Afternoon

Sunday Afternoon

The ramp up of PM2.5 during this period was fairly gradual until Saturday afternoon (Groundhog Day, 2 Feb), when there was a large spike in PM2.5 as the lake breeze pushed in.

Source: Utah Division of Air Quality

Morning soundings show that temperatures at the Salt Lake City airport increased through February first, but afterward the low levels cooled quite dramatically.

Morning (0500 MST) soundings from 29 Jan – 4 Feb 2013

Another curious oddity is that last night there was very little drop in temperature and PM2.5 at the Salt Lake City sensor above.  We have seen very large nighttime drops in PM2.5 at that station during inversion events earlier this season (or even the previous day in the trace above), but last night temperatures remained fairly constant and the PM2.5 was elevated all night long.  

So many questions, so little time.  The role of topography, radiative processes, snow cover, and the Great Salt Lake in this event deserves further investigation.  Feel free to dig in and comment.