Post on 16-Mar-2018
Utah Wintertime PM2.5 Modeling and Utah Wintertime PM2.5 Modeling and PCAPS OverviewPCAPS Overview
Lance AveyUtah Division of Air Quality
Dust
PM2.5 Speciation
Other 5%Elemental Carbon
5%
2%
5%
Organic Carbon 20% Ammonium Nitrate
58%
Ammonium Sulfate
58%
Ammonium Sulfate 9%
• Investigate the processes leading to the formation, maintenance and destruction of persistent winter t t i i th ttemperature inversions that form in the Salt Lake basin
• 1 Dec. 2010 – 7 Feb. 2011 • Modeling component being
carried out by Michigan St. (Sharon Zhong)
http://pcaps.utah.edu/
UDAQ experience with cold pool modeling:
Higher Vertical and Higher Resolution in WRFEnsemble WRF and MM5 modeling with NCARgAdjust eddy diffusivity and vertical diffusion of stable conditionsInfluence of the Great Salt LakeTested sensitivity to horizontal diffusion, roughness length, friction velocityAlbedo to adjust for wintertime snow coverAlbedo to adjust for wintertime snow cover
Strategies that improved model performance the best:Strategies that improved model performance the best:
Nudging in WRF to a modified surface analysis (FDDA) grid file to slow surface windsTurning off CMAQ vertical advectionAdding NH3 to emission fileAdding NH3 to emission file
Salt Lake City – Surface Wind Speedsph
mp
Blue – obsRed – WRF
Hours
Yellow – WRF with modified surface FDDA
CMAQ Nitrate (ug/m3)
Vertical Advection Off Vertical Advection On*Gilliam modified surface grid file *Gilliam modified surface grid file
70V t Ad ti OFF
30
40
50
60M
2.5
(ug/
m3)
Vert. Advection OFFVert. Advection ONObs.
0
10
20
30
24-h
r PM
9-Jan 11-Jan 13-Jan 15-Jan 17-Jan 19-Jan 21-Jan 23-JanSalt Lake City -- 2007
30
40
ug/m
3)
Vert. Advection OFFVert. Adection ONObs.
10
20
24-h
r Nitr
ate
(u
09-Jan 11-Jan 13-Jan 15-Jan 17-Jan 19-Jan 21-Jan 23-Jan
Salt Lake City -- 2007