January 12th, 2009

CHAPTER 8 – Weather

o   We complain about the weather, but no one does anything about it.

o   It is a play of giants, rising, spinning, sink, sweep across the continent, E to N, S to N, N to S

o   Water with ability to absorb and release heat energy fuels the drama

o   Weather vs. Climate

o   Meteorology-not study of m.

o   Air Masses:  

·         Arctic

·         Polar

·         Equadoric

·         Tropical

·         AAntarctic

o   Moisture:

·         m—maritime—wet

·         c—continental—dry

o   Humidity:

·         mT = Gulf/Atlantic air mass, late spring to early fall active  vs.

·         mt. = Pacific-low moisture content

o   As air masses migrate onshore they take the characteristics of land—cake effects of snow

o   Rain:  for air mass

o   Lifting:

·         Lift—rise—cool

·         Saturate, condense, precipitate on dust

·         Convergent lifting-lifting flows toward low pressure

·         Convection-surface hearting

·         Orographic-over a mountain, rain shadow, leeward

·         Frontal-contrasting air masses lift

o   Fronts-leading edge of advancing air mass, cold or warm

o   Cirrus clouds last night

o   Squall line

o   Dramatic weather, down drafts and wind, broken arm sailor

o   Violent weather—cyclonic storms, low pressure

·         Thunderstorms-release of condensation energy, heat and air which rises, causing up drafts-rain friction drag causes down drafts

·         Lightning-5 million lightning strikes a day on earth, 100 million volts-super heat air (25-50,000 F), violent and air expansion makes thunder

·         Hurricanes- West 180 w

·         Typhoons-Post East 180 e

·         Cyclones-ocean

o   Collapsing aquifers: (Fresno)

·         After years of groundwater mining, land levels digged 10 # meters = 33’ soil compaction and water removal

o   Pollution-

·         Remember recently here when your favorite or local gas station was closed? –Tanks replaced to cease leaking of MTBE, significant pollution, CA aquifers

o   Supply—Available Global Water

·         North America = 5,960/518 (11.5)  vs. Africa = 4220/1323 (3.4), Asia = 13200/4778 (2.7)

o   We all live downstream-e.g. New Orleans-gets water from all the other Mississippi, have used it, runoff from farms-fertilizer, pesticides, treated and untreated sewage, gas, oil from urban streets, so called Cancer ally

o   Our use = billion gallons, 1340 gal/person in 1990, 1280/person in 2000, but population is rising

·         48% hydro power

·         11% industry

·         11% domestic

·         30% farming

o   Salt Water Intrusion-Bay Delta issue

o   Ch. 9-Weather, Water Cycle, Resources

o   In the last 2 chapters we saw how exchanges of water, energy on the atmosphere drive earth’s weather.

o   Did you see on last Thursday high cirrus clouds coming in and signaling an advancing front?

o   Fortunately, water is s renewable resource (unlike oil, gas), constantly flowing through the:

·         Hydrologic Cycle

·         Global Water Balance-where water is and people are

·         Water Budgets-Receipts = precipitation, Expenses = evapotranspiration( plants) evaporation

·         Fig. 91-show

·         Fig. 92-budget

o   Time, residence of a H2O molecule:

·         10 days in atmosphere

·         3000-10,000 years in ocean aquifer, glacial ice

o   System memory-heat energy is stored in soil, water budget

o   Key is to determine the demands of crop plants, with evaporation, soil moisture requirements—just know there is higher areas of rain evaporation that affects growing seasons

o   249-254—260-270 groundwater, about half of US population uses groundwater, which comes from the sky

o   70 times more water in ground than in streams and lakes

·         It’s not quite recyclable due to the amount of time it took to accumulate

o   Aquifer-a rock sponge with pores that are saturated and hold water = table

·         Confined pressure = springs

·         Unconfined wells = pumped

·         May be formed during different climate conditions

·         Now dry and overused

·         “fossil water”

o   Groundwater-invisible to eye, slow to appreciate complexity

o   Water budget-esp. sugarcane

·         Loss of ag. Land-due to water shortage

·         Creates land crisis-land goes to development and in storm drains, runoff

·         Less into recharge

o   HI islands

·         Ancient water—too short for streams

o   Evapotranspiration

o   Evaporation

o   Advective = horizontal movement of air, when air mass migrates from one temp. to another

o   Adiabatic = a parcel of air cools by expansion up/down heats up by descending or contracting, warming or cooling rates for air parcels

o   Radiation = giving off heat = as in cooling off a parcel of ground, chilling air above it to dew point

o   Precipitation record = Mt. Waialeale, Kauai = 486”/yr = 40.5 ft.

o   Water conflicts:

·         Dams-Bonneville, OR

·         Damming the Columbia River

·         River water

·         Salmon now endangered species-fisheries, sport, commercial, hydropower, wildlife, agriculture

·         Delta, SF Bay-needs lots of freshwater to survive, push back saltwater intrusion


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