WX 201 Exam 2 with correct Answers (Graded A)

WX 201 Exam 2 with correct Answers (Graded A) Reflectivity attenutation absorption of radiation by targets WSR-88D Weather Surveillance Radar 1988 Doppler, detects precip and atmospheric movement Doppler ability to detect the "shift in the phase" of an energy pulse aircraft radar less precise than WSR-88D ground radar elevated to avoid terrain, raises elevation angle 1 degree every 360 degree scan, probably wont give you full picture of scan, cone of silence where radar can't reach warm clouds cold clouds collision-coalescence process Bergeron Process growth of ice crystals through deposition, requires coexistence of ice crystals and liquid cloud droplets supercooled water water below freezing but not frozen supersaturated condensation or or depostion evaporation or sublimation Riming Accretion of supercooled water to ice crystals as they fall in a cloud (results in graupel, or snow pellets aggregation Collision and coalescence of two ice crystals• Most effective in clouds near freezing point because crystals are "wet" and more sticky graupel snow pellets virga Small rain drops that evaporate before they reach the ground sleeting Frozen "pellets". Form when snow flakes melt above theground, then refreeze before they reach the ground freezing rain Rain that immediately freezes when it hits a surface• Very hazardous hail Embryos (graupel,frozen raindrops,insects) grow byaccretion of supercooledwater• Updrafts keep embryosin cloud for a number ofminutes• Strong/severethunderstorm required adiabatic process no energy exhange SALR (saturated adiabatic lapse rate) takes effect when air parcel reaches its dew point, varies between 5-9*C/km air parcel an amount of air that moves as a unit DALR 10°C / km• Only applicable if the air parcel is unsaturated• If air is descending, it warms at 10°C/km• Value is a constant (doesn't change) ELR Vertical change of temperature throughout theatmosphere• THIS IS THE TEMPERATURE CHANGE OUTSIDE OFTHE AIR PARCEL - THEY ARE TWO DISTINCTREGIMES Atmospheric Stability determined by ELR, highly variable Pressure Gradient Force (PGF) When a difference in pressure arises, fluids flow towards the lower pressure in an attempt to equalize. strength of the PGF depends on the pressure gradient (the change in pressure over a distance) Coriolis effect As wind begins to flow towards low pressure, the Coriolis Force (CF) affects the direction of the wind• Deflects wind to the right in the NorthernHemisphere• Deflects wind to the left in the Southern Hemisphere