TA: Courtney Obergfell

 TA : Courtney Obergfell  Discussion: Wednesdays 12:05-12:55 PM, Room 823 AO & SS  Office: AO & SS Room 1311   Office Hours: Mondays 11:00 AM-12:15 PM, Tuesdays 2:40-3:40 PM, or by appointment  Discussion Website:

 On Front  Name   Year  Intended Major  On Back  Why you signed up for a discussion section  Topics you’d like covered

 Hand in HW  Short quiz  Weather/Map Discussion  Review of last week – questions?  New lecture topic

 Atmospheric Science: the comprehensive study of the physics, chemistry, and dynamics of the earth's atmosphere, from the earth's surface to several hundred kilometers.  Oceanography: The scientific study of oceans, the life that inhabits them, and their physical characteristics, including the depth and extent of ocean waters, their movement and chemical makeup, and the topography and composition of the ocean floors.

 Government  National Weather Service: issues forecasts, warnings, fire weather, etc.  Military  Research: develops forecast models, research hurricanes, tornadoes, climate, develop satellites, etc.  Private Industry  commodity trading (agriculture, oil), energy companies (oil, wind farms), insurance/risk management, forecasting firms (transportation, construction, radio stations, etc.), air quality  Academia  Television

 Daily concerns – What to wear, flight delays, etc  Agriculture and Food concerns  Safety  Insurance and property damage  Future

 Observations allow meteorologists to assess the current state of the atmosphere  Usually taken at the same time using the same standardization across the country to be consistent  Taken by people or automated sensors

 Temperature  Dewpoint  Barometric Pressure  Wind Speed and Direction  Cloud Cover  Present Weather  Cloud Type  Etc…

 Ships  Buoys  Commercial Aircraft (ACARS)  Satellite  All of this data goes into forecast models

 Both are measured with a hygrothermometer which is shielded from the effects of direct sunlight.  Dewpoint  Dewpoint is the temperature at which the water vapor in the atmosphere condenses into liquid water.  Dewpoint is not the same as Relative Humidity.  Scientists and most of the world uses the Kelvin or Celsius scale, while the U.S. still uses the Fahrenheit scale.

 Measured with barometer  Units of hectopascals (hPa), millibars (mb) or inches of mercury (in Hg)  Reported values are adjusted to sea level -- otherwise pressure maps would simply reflect topography

 Anemometer measures speed  Weather vane tells us wind direction  Speed measured in knots:  1 knot = mph  1 knot = m/s  Weak hurricane has winds over 65 knots (75mph)! h/BAL_art/anemometer.jpg

 Amount and height  Cloud type is done by sight only

 Balloons with “radiosondes” attached are released twice per day at 72 stations in the U.S. (~900 worldwide)  Measures temperature, dewpoint, wind speed and direction and pressure as it rapidly rises throughout the atmosphere  Atmospheric “soundings” are created from these observations. These help meteorologists understand the vertical profiles of temperature, dewpoint, etc

 A very large amount of weather data can be retrieved from a given weather station

 Temperature – In U.S., expressed in degrees Fahrenheit. Most other countries, in degrees Celsius.  Dewpoint – Expressed in same units as temperature.

 Wind Direction – The line drawn represents the direction from which the wind is blowing.  Wind Speed – Represented as barbs on the line. Wind speed is measured in knots  Short barb = 5 kts  Long barb = 10 kts  Triangle = 50 kts

 Surface Pressure – Adjusted to sea level. Units are in mb.  - If reported value is greater than 500, the initial 9 is missing. Place it on the left and divide by 10. I.e.: 827 = 982.7mb  - If reported value is less than 500, the initial 10 is missing. Place it on the left and divide by 10. I.e.: 027 = mb.  Pressure Tendency – Change in pressure over last three hours. Change in pressure is represented by a value and line indicating how the pressure was changing.

 Total cloud amount represents the fraction of the sky covered

 Visibility – How far we can see from the observing point, expressed in units of miles.  Present weather conditions – Symbols are used to convey this information (rain, snow, ice, etc.).