# Corporate Profile

METR 2413 20 February 2004 Thermal Advection Since we do not directly measure vertical motions, the analysis of thermal advection on maps will provide a very useful tool for determining the vertical motions currently occurring in the atmosphere. Why use Temp. Advection? The temperature at a location may change in two ways: The air parcel which is being sampled might change its

thermodynamic state. For example, sunlight might increase its internal energy, and hence its temperature will rise. The air parcel might be replaced by a different parcel with a different thermodynamic state as the wind blows past the station. This process is called advection. In practise, both processes will operate. However, on the synoptic scale, temperature changes on timescales less than a few days are dominated by advection effects. Thermal Advection T

T T T H =-(u +v ) + ( )+ t x y c p p cp The advection term consists of a wind velocity component and a temperature gradient component.

The spatial relationship between these two is important. Thermal Advection Spatial relation between wind and temperature gradients (Geostrophic) wind is parallel to isobars. Temperature gradients are represented by isotherms. The magnitude of the pressure gradient and temperature gradient and angle between the two, isobars (wind) and isotherms, determines the strength of advection. Solenoids

When the wind crosses the temperature gradient at nearly a 90 degree angle the boxes formed on the weather map are called Solenoids. Solenoids analyzed on a weather map indicate the presence of strong advection and vertical motions. Solenoids Thermal advection Solenoids can be identified on 850 mb charts by comparing isotherms and isohypses. Also by comparing 1000-500 mb thickness and surface pressure isobars, which have historically been plotted together on weather charts (MSLP/1000500 thickness chart)

500-1000mb Thickness In addition to isotherms on a constant pressure surface, we can look at thickness compared to surface pressure Remember the hypsometric eqn? Thickness between 2 pressure surfaces is directly related to mean layer temp! Increase mean temp, increase thickness Decrease mean temp, decrease thickness This can be used as an additional tool when analyzing thermal advection Why use thickness?

Heard of the Thermal Wind? Not really a wind at all, but a vector difference between the geostrophic wind at different heights The Thermal Wind is always parallel to contours of thickness, with cold air to the left and warm to the right If we plot thickness along with surface pressures, and assume that surface winds are somewhat parallel to surface isobars, then we have 2 pieces of information 1) Surface wind vector 2) Thermal Wind vector The difference between the two is the geostrophic wind above the surface, so now we know how the geostrophic wind changes with height

Thermal Wind Cold No thermal advection: Cold Thermal windV2 is parallel to low level wind, so T geostrophicV1 windVat lower and upper levels are parallel Warm

V1 V1 V2VT V2 Warm Warm Cold V2

Cold Air Advection: Thermal wind is to the left of the low level wind, so geostrophic wind must back with height => CAA Cold Cold VT VT V1 Warm

V2 V1 VT Cold Warm Air Advection: Warm V1

Thermal wind is to the right of the low level wind, so geostrophic wind must veer with height => WAA VT V2 Warm

## Recently Viewed Presentations

• Register with HIREAMAVERICK Come to 216 Davis Hall to register See the How to use HIREAMAVERICK presentation to learn how to set up your account Complete your profile and upload a resume Through completion of your profile you'll set up...
• OGSA Next Steps Discussion Providing Value Beyond the Specifications
• Grantor and non-grantor trusts in VA pension planning. The distinction of a grantor vs. Non-grantor trust is significant. The VA compares income report to the IRS and SSA records with their records. This is referred to as an income verification...
• Little Turtle . Blue Jacket. Treaty of Fort Harmar ... never did I see, As happened on the plains, near the River St. Marie.3. Our militia were attacked, just as the day did break, And soon were overpowered, and forced...
• European Exploration of the Americas American Journey
• Side note: The housing crisis occurred because many banks were giving mortgages to couples who were poor credit risks.They couldn't pay back the full mortgage payments over the course of the loan.While they could pay off the payments in the...
• Mice, fruit flies, and the roundworm Caenorhabditis elegans DNA Technology Section 2 Genetics and Biotechnology Transgenic Plants Genetically engineered cotton resists insect infestation of the bolls. Sweet-potato plants are resistant to a virus that could kill most of the African...
• Pličanič, Senko, Pravica do dostopa do informacij javnega značaja, zbornik referatov z IX. Dnevov slovenske uprave. Prof. dr. Slobodan Dujić Modernizacija javne uprave . Modernizacija javne uprave - literatura. Priporočena literatura ...