Lab 4 Orographic Lifting, Apparent Temperature, Satellite Imagery, Radar Imagery, Surface Patterns of Pressure and Wind, Constant Pressure Surfaces

On labs and stuff…  Please read/answer the whole problem.  Use units.  Come to my office hours/ask me anything  Review for midterm: 10/1 7:30-8:30

Orographic Lifting ● Orographic - of or related to mountains; associated or induced by the presence of mountains ● Orographic Lifting - lifting of air by terrain ● Clouds form when air rises ● Clouds disperse when air sinks

Orographic Lifting erh.noaa.gov

Apparent Temperature ● What the temperature “feels like” to the average person if the effect of moisture content of the air is taken into account ● AKA “Heat Index,” AccuWeather’s “RealFeel” ● Apparent Temperature = Air Temperature + (Vapor Pressure -16) ● Find the Apparent Temperature: ○ T = 80°F, T d = 70°F ○ Equilibrium Vapor Pressure at 70°F is 25mb ○ T a = 80 + (25-16) = 89°F

Satellite Imagery - Visible ● Uses visible radiation from the sun back-scattered off objects on the earth ● Meteorologists are able to distinguish between different cloud types because of differences in albedo ● Thick clouds (i.e. Cumulonimbus) have higher albedo than thin, wispy clouds (Cirrus) ● Since it uses radiation from the sun, it’s only useful with daylight

Satellite Imagery - Visible

Satellite Imagery - Infrared ● Uses infrared radiation emitted by the earth and objects near the surface (i.e. clouds) ● Distinguish between high and low clouds based on temperature and the amount of radiation the cloud emits ● Useful day and night since objects always emit radiation

Satellite Imagery - Infrared

Satellite Imagery - Water Vapor ● Water vapor is the dominant emitter of infrared radiation around 6.7 microns ● Satellites are calibrated to measure this radiation so we can get a sense of water vapor in the atmosphere ● BUT...a radiometer attuned to radiation at wavelengths near 6.7 microns can only detect water vapor residing in the upper or middle regions of the troposphere

Satellite Imagery - Water Vapor

Radar Imagery ● RAdio Detection And Ranging ● Ground-based remote-sensing instruments ● First successfully used in World War II ● Radar works by transmitting pulses of radio waves from an antenna. The pulse is reflected off a “target,” such as a rain shower, and returns to the radar’s receiver giving us the size and distance of the target

Radar Imagery

Radar Imagery - Complication  Height of radar beam increases with distance from radar  Sometimes overshoots shallow clouds/precipitation

Surface Patterns of Pressure and Wind ● 3 Forces that Control the Wind ○ Pressure Gradient Force (PGF) ○ Coriolis Force ○ Friction

Pressure Gradient Force (PGF) ● The wind is caused by differences in air pressure ● Pressure Gradient Force - force that sets the air in motion in a determined effort to erase the pressure gradient

Coriolis Force/Coriolis Effect ● The force that deflects objects moving along the surface of the earth to the right in the northern hemisphere and to the left in the southern hemisphere ● Caused by the rotation of the earth ● CCW rotation around lows ● CW rotation around highs

Friction ● The Earth’s surface is not smooth (mountains, hills, trees, buildings, etc.) ● Acts to slow wind speeds and reduce the effect of coriolis Lake Erie Wx

Correcting to Sea Level Pressure ● Air pressure decreases with increasing altitude ● What city has a higher surface pressure: Miami, FL or Denver, CO? ● We correct to sea-level pressure because it removes the effect of elevation

Constant Pressure Surfaces (Heights) ● Surfaces (height) at which pressure is constant ● The same pressure does not occur at the same height everywhere, so these surfaces are not flat

Heights and Temperature

Lab 4 ● 4.14(a,b) ● 4.15(c) ● 5.4(a,b,c) ● 5.10(a,b) ● 5.18 ● 6.2(a,b) ● 6.7(a,b) ● 6.9(a,c,d) ● 7.9(a,b)