February 21, 2006 Lab

1. February 21, 2006 Lab Dan Kurz & Matt Chyba Team 4

12. Analysis Summary Visible Satellite maps Synoptic scale vertical motions are shown on the isentropic analysis very well. Ascending motion, winds moving from high pressure to lower pressure, is observed in the gulf coast region and coincides with the clouds shown on the visible image. Descending motion, winds moving from lower to higher pressure, is found from central Iowa SE to North Carolina. This is an area that coincides with generally clear skies. The 300K isentropic map depicts the cloudy areas of the gulf coast the best out of the four levels chosen. Interesting to point out is that although the 300K map shows cloudy areas the best, the R.H. fields are contoured the highest in the 295K map. We aren’t sure why this is occurring besides the fact that the moisture is found in the lower parts of the atmosphere. Places where rising motions are not depicted, but clouds are still observed, occurred in the central Oklahoma region where the winds generally moved parallel to the isentropic surface. R.H. Field maps When analyzing the R.H. field, the isentropic analysis corresponds in an accurate manner such that the high levels of R.H. correspond to areas of rising motion and cloud cover. Similarly, areas of cloud free descending motion have no relative humidity greater 60% and shown to have no cloud cover. The area of cloud cover in Oklahoma, where rising and sinking motions are not found, contains low values of R.H.~60% and seem to be not as thick as the clouds SE of that location. 900mb and 850mb maps Both maps depict WAA occurring from central Texas SE towards the central Gulf of Mexico. This WAA is more easily found in the 900mb map. The R.H. fields found on the pressure surface map are similar to the isentropic surface map and support the cloud cover along the Gulf Coast and mid-south region. CAA is not as easily found on these maps. Some, although weak, can be found along the Virginia/N. Carolina border and from central Nevada south to the Mexico/California border. CAA is depicted along the Pacific coast, but this is likely due the ocean currents and upwelling found along the coast. Overall, the pressure and isentropic surface maps do a good job of matching wind and humidity criteria. Both of these maps help identify areas of WAA, CAA, cloudy skies and clear skies. Both maps also depict the transport of moisture in the SE very well. These maps are basically telling us the same information, but doing it using two different surfaces.

13. CAA WAA

17. In areas of warm air advection, air has ascended roughly 1-2 km. In areas of cold air advection, air has descended roughly 3-4 km. Air will continue to rise in areas of warm air advection for roughly 3 more km after crossing the 850mb surface, leveling off at about 700mb Air continues to descend in areas of cold air advection for roughly 1 more km after crossing the 850mb surface, leveling off at about 920mb.

18. This system is not predicted to produce much precipitation. By looking at the RH field, we can notice low RH values closer to the surface with the higher RH values in the middle part of the atmosphere. As the precipitation falls through the lower atmosphere, evaporation will occur and thus lessen the total precipitation values that are associated with this system. If the surface RH values were higher, the system would yield more precipitation at the surface.

19. This map shows winds in geostrophic balance and that tells us that there is little dynamic forcing to further enhance this clipper system. This map and the 850mb map are different because while the trough is apparent on the 850mb map, the trough is vaguely identifiable on this map. Similar winds throughout Texas and Oklahoma are depicted on both maps, but differ greatly in the Dakotas. The 850mb map shows winds at the 850mb level while this isentropic map shows winds as they follow the movement of the air parcel.