Evaluating Soundings. Assignment 6. Due February 22
Purpose: (1) to examine soundings at SLC as a cold front passes; (2) examine the temporal and spatial
structure of a major winter storm over the intermountain region.
The IPEX field program makes it possible to examine the evolution of the atmosphere at 3 h intervals over the intermountain region.
Review the information on the interpretation of soundings from the Djuric text and the skew-T manual.
Become familiar with the locations where soundings are taken in the intermountain region.
Soundings for the following times will be analyzed:
- 12z 14 February 00
- 15z 14 February 00
- 18z 14 February 99
- 21z 14 February 99
- 00z 15 February 00
- 03z 15 February 00
- 06z 15 February 00
- 09z 15 February 00
- 12z 15 February 00
Review the synoptic situation at each time by using information on the web or that handed out in class
1. Examine each sounding carefully for 12z 14 February and identify and label the following features, if they exist:
- questionable observation (QO)
- surface radiational inversion (RI)
- strongly stable layer in the troposphere (isothermal or inversion layer) (SS)
- tropopause (T)
- melting level (0)
- maximum wind layer (J)
- other jets (J)
- lowest cloud base (CB)
- lowest cloud top (CT)
- dry adiabatic layer (DA)
- saturated adiabatic layer wrt water or ice (SA)
2. On the accompanying 4 panel blank maps, label for 12z 14 Feburary (in mb):
- upper left: height of the tropopause
- upper right: base of any strong stable layers in troposphere (that is not a radiational inversion)
- lower left: melting level
- lowest cloud base
3. Repeat 1 and 2 for each time
7. Based on the soundings and the summary maps, describe the temporal evolution of the vertical structure of the troposphere during the 24 h period:
- how did the height of the tropopause and level of maximum wind change in space and time?
- how did the thermodynamic structure in the lower troposphere evolve in terms of, for example, the melting level and height of strong stable layers?
- indicate the approximate location of the surface cold front based on the sounding information