Lecture 4
description
Transcript of Lecture 4
Lecture 4
Weather Maps and Models
Chapters 3 and 4
Homework
• Due Friday, September 22, 2006 (add to previous homework)
• Ch 4 TYU 2,6,9,12,14,17,18,23,25 TYPSS #2
Meteograms
• Display state variables graphically over a period of time.
• AOS rooftop site:
http://rig.ssec.wisc.edu/
Surface Station Model
Surface Station Model
Weather Symbols
Surface Maps
Station Plots Dew point analysis
MSLP analysis (mean sea level pressure)
Temperature analysis
Upper Air Station Plot
Upper air charts
http://www.aos.wisc.edu/weatherdata
Upper Air chart(Constant pressure surface)
Upper air charts
http://www.aos.wisc.edu/weatherdata
Forecasting Weather
Weather Models
• Mathematical equations describe how:– Air accelerates or decelerates based on Newton’s
Laws– Mass of air and its properties move from one position
to another while conserving properties of mass and energy
– Mass of water vapor is moved and transformed to rain and snow
– Air is heated or cooling by condensation, radiation • These differential equations are integrated
forward in time by solving them numerically on a grid
Two Basic types of Models
• Finite Difference Model– Solved on a grid– Taylor series approximations to continuous equations
• Spectral Model– Analysis of variables on a grid in real space is
transformed to a grid in wave space grid using a Fourier transform
– Equations moved forward in wave space analytically– Variables transformed back to real space
Examples of Horizontal Grids
Vertical Grid
Vertical grid may be :
•Height coordinate
•Pressure coordinate
•Sigma or terrain following coordinate
Map Projection
Various map projections are used to take into account the curved Earth surface. For instance:
1. Mercator projection
2. Polar Stereographic Grid
3. Lambert Conformal
4. Spherical Grid
Topography Representation
Ensemble Prediction
Look at AOS Web Page
• Real Time analysis and Prediction available on the Web:
Weather Maps (Current and Forecast Maps):
http://www.aos.wisc.edu/weather/index.htm (Maps drawn by UW AOS Department)http://cup.aos.wisc.edu (Tripoli’s NMS Model output)http://www.nws.noaa.gov/outlook_tab.php (National Weather Service Maps)http://weather.unisys.com/ (Unisys (Purdue) Maps….traditional leader in Internet map technology)http://www.meteo.psu.edu/%7Egadomski/ewall.html (Penn State Electronic Maps)http://www.atmos.albany.edu/weather/difax.html (NWS difax maps from SUNY Albany)http://www.rap.ucar.edu/weather/ (National Center for Atmospheric Research Weather)http://hdrweather.com/f2p2/default.htm (Colorado weather by Henz)