Representativeness of MesoWest Observations
and Other VTMX-Related Issues

John D. Horel, David Myrick, Mike Splitt*, Steven Lazarus**, Lacey Holland***, Alex Reinecke****

Department of Meteorology

University of Utah

jhorel@met.utah.edu

* Telecommuting from Florida

** Florida Institute of Technology

*** NCEP

**** University of Washington

Current Focus

Cold Pool Structure

Clements, C., 2001: Cold Air Pool Evolution and Dynamics In A Mountain Basin. M.S. Thesis. University of Utah. 100 pp.

Clements, C., D. Whiteman, J. Horel, 2003: Cold pool evolution and dynamics in a mountain basin. Submitted to J. Appl. Meteor.

Climate in Salt Lake Valley and other Basins in the West

How well can MesoWest observations define local microclimates, e.g., diurnal temperature range?

IOP-2. 6-7 October

Holland, L., 2002: Downslope Windstorms Along the Wasatch Front. M. S. Thesis. University of Utah. 86 pp. (copies available)

** Horel, J. and L. Holland, 2002: Downslope windstorms along the Wasatch Front. Manuscript in preparation.

Data Assimilation in Complex Terrain for other IOPs

Lazarus, S., C. Ciliberti, J. Horel, 2002: Near-real time applications of a mesoscale analysis system to complex terrain. Wea. Forecasting. In press.

Sensitivity to analysis methodology: overcoming systematic analysis errors in complex terrain

IOP-2: 6-7 October

Complex interactions between stable boundary layer and synoptic-mesoscale forcing

Well-developed radiational inversion in Salt Lake Valley

Cold pool over Wyoming approaching Wasatch

After 10:30 UTC:

Bora-type surface winds confined to narrow region along northeast bench

Jet emanating from northeast corner of SL Valley above cold pool

Stagnant conditions in downtown SLC

Conceptual model of IOP 2:
7 Oct 2000 (0400 UTC)

Vertical Structure at 0400 UTC

Conceptual Model of IOP 2
0700 UTC

Conceptual Model of IOP 2:
0830 UTC

Tethersondes at 1000 UTC

Conceptual Model at 1030 UTC

“Good” ADAS Wind Analysis : IOP-2

“Bad” ADAS Temperature Analysis: IOP-8
1200 UTC 20 October

ADAS Analyses Applied to VTMX

1 km horizontal resolution incorporating all available observations collected during IOPs

Analysis = Background + Correction

= RUC-2 + S weight x (observation – background)

Biases:

Surface observations on slopes/peaks affecting free atmosphere above valleys. Developed “terrain weighting factor”

Analyses too smooth in horizontal and vertical. Reduced horizontal and vertical radii of influence

Surface observations from adjacent valleys affecting analysis. Developing “anisotropy weighting factor”

Mass/wind fields not constrained to be dynamically consistent. Developing variational constraint on wind field

Anisotropic Weighting Term

Slide 20

“Better” ADAS Temperature Analysis: IOP-8
1200 UTC 20 October

1200 UTC 20 October. IOP-8

What’s Next?

Fully implement anisotropy factor into ADAS

Analyze spatial and temporal evolution of boundary layer during IOP-8 at 1 h intervals on 1 km grid using all available data

Use analyses to initialize simulations of IOP-2 and IOP-8

Analyze other IOPs as time permits

Continue development of variational wind constraint



	John D. Horel, David Myrick, Mike Splitt, Steven Lazarus, Lacey Holland, Alex Reinecke**
	Department of Meteorology
	University of Utah
	jhorel@met.utah.edu

					* Telecommuting from Florida
					** Florida Institute of Technology
					*** NCEP
					**** University of Washington


	Cold Pool Structure
		Clements, C., 2001: Cold Air Pool Evolution and Dynamics In A Mountain Basin. M.S. Thesis. University of Utah. 100 pp.
		Clements, C., D. Whiteman, J. Horel, 2003: Cold pool evolution and dynamics in a mountain basin. Submitted to J. Appl. Meteor.
	Climate in Salt Lake Valley and other Basins in the West
		How well can MesoWest observations define local microclimates, e.g., diurnal temperature range?
	IOP-2. 6-7 October
		Holland, L., 2002: Downslope Windstorms Along the Wasatch Front. M. S. Thesis. University of Utah. 86 pp. (copies available)
		** Horel, J. and L. Holland, 2002: Downslope windstorms along the Wasatch Front. Manuscript in preparation.
	Data Assimilation in Complex Terrain for other IOPs
		Lazarus, S., C. Ciliberti, J. Horel, 2002: Near-real time applications of a mesoscale analysis system to complex terrain. Wea. Forecasting. In press.
		Sensitivity to analysis methodology: overcoming systematic analysis errors in complex terrain


	Complex interactions between stable boundary layer and synoptic-mesoscale forcing
		Well-developed radiational inversion in Salt Lake Valley
		Cold pool over Wyoming approaching Wasatch
	After 10:30 UTC:
		Bora-type surface winds confined to narrow region along northeast bench
		Jet emanating from northeast corner of SL Valley above cold pool
		Stagnant conditions in downtown SLC


	1 km horizontal resolution incorporating all available observations collected during IOPs
	Analysis = Background + Correction
	= RUC-2 + S weight x (observation – background)
	Biases:
		Surface observations on slopes/peaks affecting free atmosphere above valleys. Developed “terrain weighting factor”
		Analyses too smooth in horizontal and vertical. Reduced horizontal and vertical radii of influence
		Surface observations from adjacent valleys affecting analysis. Developing “anisotropy weighting factor”
		Mass/wind fields not constrained to be dynamically consistent. Developing variational constraint on wind field


	Fully implement anisotropy factor into ADAS
	Analyze spatial and temporal evolution of boundary layer during IOP-8 at 1 h intervals on 1 km grid using all available data
	Use analyses to initialize simulations of IOP-2 and IOP-8
	Analyze other IOPs as time permits
	Continue development of variational wind constraint