ATMO 336 1st Edition Lecture 4 Outline of Last Lecture II. Longwaves and the temperature patternIII. 500mb height pattern and precipitationIV. lifting of aira. divergenceb. convergenceV. common weather terminology; indicators of trough strengtha. zonal patternb. amplified (meridional)VI. shortwavesVII. closed lows and cutoff lowsOutline of Current Lecture VIII. numerical models of weatherIX. errors in numerical forecastsX. dilemma for weather forecastersXI. ensemble weather forecastingXII. The atmospherea. Defining meteorologyb. Essential functions of atmosphereCurrent Lecture- Numerical models of weather o Based on fundamental math equations which describe physics and dynamic movements in atmosphereo These models are Very complex Deal with a huge quantity of data Require large number of calculationso Need fast computers with large memory systemso Numerical model evolves with time- Errors in numerical forecastso Often a representation of the model, not exact Simulating atmosphere are not precise Many processes in atmosphere are not fully understood Initial conditions not exact (this uncertainty is what most limits our ability to make accurate future weather predictions)These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.o Errors tend to amplify with time Beyond 12 days from forecast, models have little skill in predicting weather- Dilemma for weather forecasterso Dozens of different models= each model gives a different forecast (very confusing to forecasters)o Limit to how well the future state of the atmosphere can be predicted- Ensemble weather forecastingo Each computer weather forecast model is run many times, but with slightly different initial conditions. This can be used to create a probability forecast- The atmosphereo Layer of gaseso Relatively thin o Habitable atmosphere= where humans can survive without breathing assistance (extends only about 6 kilometers (4 miles) above sea levelo Air density= highest at surface Thin air= at high altitudes Air becomes less denseo Retained by earths gravityo Aerosols= dust, pollen, cloud droplets (very small, but high concentrations)o Troposphere= where all weather and clouds are formed (15km or 10 miles) Contains 75% of atmosphere by weight- Meteorologyo Study of the atmosphere and the processes (such as cloud formation, lightning, and movement of wind) that cause “weather”.o Weather systems develop as result of flow of heat from warmer regions near equator to colder regions near poles- Essential functions of atmosphereo Contains oxygen to allow life to survive and carbon dioxide to allow plants to grow and form base of food chaino Acts as a shield; protects form UV radiation and other high energy particles form sun andspace (meteors)o Transports heat and moisture creating more uniform conditions around globe than if there were no atmosphere (w/o atmosphere, much larger extremes in temps)o Keeps average temp of earth warmer through greenhouse effecto Influences existence of sound (sound does not travel in empty space)o Provides visual sights (blue skies, clouds, ect.)o Provides sense of
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