Presentation on theme: "Chapter 1 9/2/20091. There is no upper limit of the atmosphere, but it rather becomes thinner and thinner, merging with empty space. greenhouse effect."— Presentation transcript:
There is no upper limit of the atmosphere, but it rather becomes thinner and thinner, merging with empty space. greenhouse effect = warming that results when solar radiation is trapped by the atmosphere; caused by atmospheric gases that allow sunshine to pass through but absorb heat that is radiated back from the warmed surface of the earth. 9/2/20092 Water is the only substance that can be found naturally in the atmosphere in its 3 phases (solid->ice, liquid->water, gas->water vapor) -laughing gas
Vertical Structure of the Atmosphere Air Pressure and Air Density Weight (force acting on an object due to gravity) = mass x gravitational acceleration = m x g Density = mass/volume (air density at sea level ~ 1.2 kg/m 3 ) Pressure = force/area At the Earth’s surface the pressure of the atmosphere is 14.7 lbs/in 2. Standard sea level pressure is: 1013.25mb=1013.25hPa=29.92 in.Hg. Atmospheric pressure decreases with an increase in height. 9/2/20094
Vertical Structure of the Atmosphere Layers of the Atmosphere - Pressure & Density decrease with height - Air temperature has a complicated vertical profile Lapse rate = the rate of change (decrease) in temperature with a change in height; the average lapse rate in Troposphere = - 6.5 C / 1 km. Inversion layer = change in the sign of the lapse rate, + 6.5 C / 1 km. Isothermal environment = no change in temperature with height 9/2/20097
Fig. 1-11, p. 13 9/2/2009 Layers of the atmosphere as related to average profile of air temperature.
Vertical Structure of the Atmosphere Observation: Radiosonde Weather balloon Instrument and transmitter Air temperature, humidity, pressure 9/2/20099
Vertical Structure of the Atmosphere The Ionosphere Not a true layer but an electrified region within the upper atmosphere ( from about 60 km to the top of the atmosphere ) where fairly large concentrations of ions and free electrons exist. Ions = molecule with an additional or minus an electron Sun light creates layers: F (at 180 km),E (at 120 km), D (at 60 km) layers Ionosphere plays a major role in AM radio communications 9/2/200910
9/2/200911 At night, the F region of ionosphere strongly reflects AM radio waves, allowing them to be sent over great distances. During the day, the lower D region strongly absorbs and weakens AM radio waves, preventing them from being picked up by distant receivers.
9/2/200912 (more solar eruptions) Based on composition of the atmosphere
Weather and Climate Weather: short term changing in air temperature, air pressure, humidity, clouds, precipitation, visibility, and wind Climate: long term patterns and average weather; not just magnitude but also frequency Assignment 1 9/2/200913
Weather & Climate Meteorology Study of the atmosphere and its phenomena Aristotle 340 B.C. – book on natural philosophy, Meterologica. – Greek word = meteoros = “high in air” – sum of knowledge at that time The birth of Meteorology as a natural science did not take place until the invention of weather instruments: thermometer ( end of 16 th century), barometer (17 th century), hygrometer (18 th century). 1843 telegraph invented 1920s concepts of air masses and fronts 1940s upper air balloons 1950s radar and computers 1960s satellite 9/2/200914
9/2/200915 Doppler radar has the capacity of estimating rainfall intensity.
Weather & Climate Satellite’s View Geostationary satellite: situated at about 36,000Km (22,300mi) above the earth. Satellite travels at the same rate as the earth spins, which allows it to remain positioned above the same spot. Meridians measure longitude (W-E): lines running from north to south. Prime meridian (0 0 meridian) runs through Greenwich, England. Parallels to equator (0 0 latitude) measure latitude (N-S) Weather maps: pressure cells, fronts, surface stations 9/2/200916
Fig. 1-15, p. 20 9/2/200917 Satellite Image: clouds+ storms at surface
9/2/200918 Simplified surface weather map that correlates with the satellite image shown.
Weather & Climate Weather and Climate in Our Lives Two general reasons for studying how weather and climate impacts our lives: economic efficiency and public safety. Crops Utilities Extreme cold and heat Tornados and hurricanes Clothing Meteorologist Any person with a college degree in meteorology or atmospheric science; not just the TV weather person Half of 9000 meteorologists employed by the US National Weather Service Researchers and operational meteorologists 9/2/200919
Energy, Temperature, & Heat Energy is the ability to do work (push, pull, lift) on some form of matter. Potential energy is the potential for work. Gravitational potential energy: Kinetic energy is energy of a moving object Total energy = PE + KE Temperature is a measure of the average speed of atoms and molecules. High temperature corresponds to high average speeds
Energy, Temperature, & Heat Which has more energy? A lake or a cup of hot tea? Heat is the energy in the process of being transferred from one object to another because of a difference in temperature. First Law of Thermodynamics: Energy cannot be destroyed or created conservation of energy