ATMS review guide 2From Before- Weather is what you get and climate is what you expect- Satellites- view clouds from spaceRadar- view precipitation from the ground- From where it is coming from- Low-counterclockwise and inward high- clockwise/outward- Low usually precipitation high usually clear weather - Pressure-force per unit and always decreases with height - Density- mass/volume and always decreases with height- Inversion-layer in which the temperature decreases with height- Warm air is less dense than cold air and moist air is less dense than dry air- Advection-transfer of heat (or moisture) through horizontal movement of air example i The sun heats the lower atmosphere because the sun heats the surface, the layer of air about 1 cm or so above the ground is then heated, the hot air expands becomes less dense and rises the troposphere is now heated from the bottom up- As hot air rises the pressure around it decrease so it expands, it requires energy for a parcel to expand, the temperature of the parcel cools as it expands- summary hot less dense air rises, expands, and cools- It takes much more energy to heat water than to heat air or land- Clouds result in cooler temperatures during the day and warmer temperatures at night- Saturation occurs when evaporation and condensation rates are equal- Relative humidity- ratio of water vapor in air (VP) to that required for saturation (SVP)- RH does not indicate actual amount of water vapor in air-increase by adding moisture to the air (increase VP) or by cooling the air (decrease SVP)- decrease by removing moisture from the air or warming the air- Dew point temperature- the temperature at which saturation occurs, a higherdewpoint always means there’s more moisture in the air, dew point is always less than or equal to temp- as air rises it expands and cools amount of water vapor in air does not changeas air rises ( see image 4) as temperature decreases, relative humidity increases, air eventually rises high enough (cools enough) to become saturate, when air saturate clouds form- orographic lifts, warm fronts, cold fronts. Convergence - 10-12 inches- Sleet-requires a think above freezing layer of air aloft and a deep below freezing layer near surfaceFreezing rain-requires a deep above freezing layer of air aloft and think below freezing layer near surfaceLecture 9- Constant pressure surface- uniform surface pressure and temperature- this means that constant pressure surfaces parallel to constant height surfaces (see diagram 1) - High heights show warm air below that pressure level (warm air is less densethat cold and expands as you heat) low heights show that there is cold air below that pressure level (see pic 2)- Trough- valley low heights and ride is high heights and pressures (don’t just look at shape of lines)- PGF- air molecules want to flow from where these is greater pressure to where there is less pressure (pic 3)o Increasing the PGF gives you greater acceleration and faster flow o PG= change in pressure/distanceo Tightly packed isobars- strong PG widely space is weak- PGF cause wind to blow the stronger PGF yields stronger wind- Wind blowing on the earth is analogous to throwing the ball on the merry-go-round, if a merry go round is not moving the ball won’t be deflected once its moving the ball will still travel in a straight patho Deflects objects to the right in the northern hemisphere- As the wind speed increases the coriolis force increases and vice versa - No it does not- the coriolis effect is present in all motions relative to the earths surface but in most of our every day experiences the force is so small its negligible Lecture 10 - Upper level winds tend to parallel the contour lines - PGF blows - When the PGF and coriolis force are equal and opposite (see pic4 ) A wind that blows at a constant speed parallel to straight isobars- In lows PGF > coriolis in highs coriolis > PGFo Must have these forces imbalances or flow would not go in a circle o Need a net force inward toward center of circle - Asd- Cyclones- low pressure systems- NH flow counter clockwise SH flow clockwiseAnticyclones: High-pressure systems NH flow clockwise SH flow counter clockwise- Friction - Friction- opposes motion and slows down the winds weakening the coriolis force-disrupts force balance seen with upper level flow Lecture 11- An air mass is a large body of air with similar temperature and moisture concentrations in the horizontal- Centers of air masses are surface high pressure systems- Classified based on moisture and temperature-Two-letter classificationo First letter refers to moisture, second letter refers to temperatureo Moisture: Continental (c): Dry (forms over land) Maritime (m): Moist (forms over water)o Temperature Tropical (T): Warm/hot Polar (P): Cool/cold Arctic (A): FrigidcP = Continental Polar- Dry and cold- cT = Continental Tropical- Dry and hot- mP = Maritime Polar- Moist and cool- mT = Maritime Tropical- Moist and warm- cA = Continental Arctic- Dry and very cold- See picture 5- Fronts are boundaries between air masses of different densities- Cold front- blue triangles warm front- red semi-circles occluded- combo - Front are identified by the wind direction relative to the front in the cold air- Cold front- winds in cold air blow toward front, cold air is advancing, becausewarm air is less dense cold air lifts it upward and usually precipitation brief but intense showers- Warm front- winds in cold air blow away from front, warm air is advancing, less dense air gradually overlaps dense cold air, precipitation is widespread- Stationary fronts- do not move, the winds in the cold air blow parallel to the front, mixed precipitation often north of front- Generally associated with widespread rain or snow- Occluded fronts-As a low pressure system strengthens, it wraps cold air around itself-when the cold front “catches up” to the warm front, the warm air is forced aloft and an occluded front forms-temperature may rise or drop slightly but remain cold- Dry lines- Separate mT air (warm/moist from gulf of Mexico to east) from cT air (hot/dry from deserts to west), during spring can trigger strong to severe thunderstorms, typically found in KS, OK, or TX- Temperature gradient-Large change in temperature with distance, tightly packed isothermsDewpoint (moisture) gradient- tightly packed isodrosothermsWind shift- remember how to determine winds from surface isobars to helpTrough of low pressure at the