Clim 301 Lab6

Sep. 30 Lab: (due Oct. 7) Advection

Note: it has been pointed out that the station data in the southern gulf states (Mississippi, Louisiana, etc.) does not match the model analysis very well. In particular, the station in Mississippi has warm advection if one uses the model analysis maps provided below, but that station has cold advection if one looks at the station data and draws their own Isotherms.

Please indicate on your lab assignment which isotherm analysis you are using: the model analysis map provided at the end of this web page, or your own isotherm analysis.

This lab is an introduction to determining temperature advection on a msp.

For this lab, you will analyze an 850mb chart. On the 850mb chart, when plotting geopotential heights, the first digit, a one, is customarily dropped. (So a value of 483 means 1483 meters).

The 850mb chart is fairly close to the surface. Over much of the US, it is high enough to avoid strong surface influence. The air is warmer than the higher levels, and potentially more moisture laden.

Over the mountain terrain in the western US, there are many places where the surface pressure is less than 850mb. The chart is not analyzed for these regions.

For this assignement, you will examine the temperature advection on the 850mb chart that is provided. The plots below show the streamlines for this time and the temperature contours for this time. These maps were produced using model analysis data.

By examining the wind flow and temperature fields, determine at each station if warm air advection is taking place. If it is, circle the temperature at that station.

Only do this for the stations in the US that are east of the Rocky Mountains. You do not need to examine stations in Canada or Mexico. For stations along a coastline, it may not be possible to determine the temperature field sufficiently, due to lack of data over the oceans.

The map you will analyze is linked HERE.

The maps below are provided to assist you in determining the advection. Remember that streamlines crossing isotherms from warmer to colder indicates warm air advection (WAA), and streamlines crossing isotherms from colder to warmer indicates cold air advection (CAA).

You may find it useful to sketch the isotherms and streamlines on your map. Use the radiosonde reports to fine-tune the streamlines and contours -- don't assume the computer model analysis will match the observed data.

Bonus: identify the upper level fronts over the US, east of the Rockies.