February 15 (Week 4) Term Paper Topics Isopleths HW#4 Weather Review

February 15 (Week 4)

• Term Paper Topics

• Isopleths HW#4

• Weather Review

• Temperature and Humidity (Chapter 3)

• Vehicles and Hyperthermia

• Midterm Review

TonightTonight

• CLASS WILL BEGIN AT 6:15 PM

• MIDTERM #1MIDTERM #1

• 33 multiple choice questions

• No Scantron

• Term Paper Topics Due (HW #5)

• Textbook

• List from Syllabus

• PRIMARILY ABOUT METEOROLOGY!!

• Not Acceptable: Seasonal Affective Disorder (SAD), Frostbite, Earthquakes, Tsunamis, Waves for Surfing

Next Week (2/22)Next Week (2/22)

http://funnel.sfsu.edu/courses/jnull/metr302/f10/Term%20Paper%20Topics.pdf

Term Paper TopicsTerm Paper TopicsTerm Paper TopicsTerm Paper Topics

Famous People in Meteorology - Galileo - Fahrenheit - Celsius - Luke Howard - Bjerknes - Beaufort - Fujita - Da Vinci

Famous Weather Events 1900 Galveston Hurricane 1935 Labor Day Hurricane 1938 New England Hurricane Great Blizzard of 1993 Hurricane Andrew (in 1992) Hurricane Betsy (1956) Hurricane Carol (in 1954) Hurricane Georges (in 1998) Hurricane Gilbert (in 1988) Hurricane Hugo (in 1989) Hurricane Katrina (in 2005) Hurricane Mitch (in 1998) Moore OK Tornado Outbreak - 1999 Palm Sunday tornado outbreak - 1965 Columbus Day Storm (W. Coast 1962) Calif. Great Floods of 1862 The Perfect Storm (1991)

HW#5 – Pick a topic by next week.

Term Paper TopicsTerm Paper TopicsTerm Paper TopicsTerm Paper TopicsSpecific Weather Topics acid rain air pollution Air Quality Index (AQI) anemometer atmospheric circulation aurora borealis ball lightning blizzards Cape Verde-type hurricane chinook wind cloud types contrail cyclone El Nino/La Nina fall wind - katabatic wind fires and weather freezing rain frost Fujita scale (for measuring tornadoes)

fulgurite global warming hail halo optical phenomenon heat wave humidity hurricanes ice storms katabatic wind lightning history of meteorology history of the National Weather Service ozone depletion (i.e., ozone hole) Pacific DecadalOoscillation paleoclimatology rainbow Saffir-Simpson Hurricane Scale Santa Ana Winds smog solar energy

space weather storm surge sundog - parhelion temperature scales thermometers tornadoes weather instruments weather folklore wind energy

Homework #4 SolutionHomework #4 Solution

Weather ReviewWeather ReviewWeather ReviewWeather Review






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TEMPERATURE AND HUMIDITY EXTREMES

TEMPERATURE AND HUMIDITY EXTREMES

CHAPTER 3CHAPTER 3

Temperature MeasurementsTemperature Measurements• ~5 feet above the ground

• Over natural surface

• Well ventilated

• Out of Direct sunlight

• Away from heat sources

• Parking Lots

• Motor Vehicles

• South facing buildings

TEMPERATURE SCALE HISTORYTEMPERATURE SCALE HISTORY• Fahrenheit -1700sFahrenheit -1700s

• 0 ° = freezing point of brine0 ° = freezing point of brine• 32 ° = freezing point of water32 ° = freezing point of water• 100 100 ° = ° = body temperaturebody temperature

• Celsius – 1700s Celsius – 1700s • 0° = freezing point of pure water0° = freezing point of pure water• 100° = boiling point of water100° = boiling point of water

TEMPERATURE SCALESTEMPERATURE SCALES• Lord Kelvin – 1700sLord Kelvin – 1700s

• Proved lowest temperature was -273°CProved lowest temperature was -273°C• 0 °K = Absolute Zero0 °K = Absolute Zero• 273 °K = freezing point of water273 °K = freezing point of water• 373 °K = boiling point of water373 °K = boiling point of water

EARLY THERMOMETERSEARLY THERMOMETERS

• First Thermometers used AlcoholFirst Thermometers used Alcohol• Superseded by Mercury (Hg) - 1717Superseded by Mercury (Hg) - 1717

• More pureMore pure• OpaqueOpaque• Immune to evaporationImmune to evaporation• Liquid over a wider range of tempsLiquid over a wider range of temps

• -38° F to 357 ° F-38° F to 357 ° F

TEMPERATURE CONVERSIONSTEMPERATURE CONVERSIONS

Fahrenheit to CELSIUSFahrenheit to CELSIUS° C = 5/9 (° F-32)° C = 5/9 (° F-32)

Celsius to FAHRENHEITCelsius to FAHRENHEIT° F = (1.8 ° C) + 32° F = (1.8 ° C) + 32

FOR PRACTICAL PURPOSESFOR PRACTICAL PURPOSES1° C = 2 °F1° C = 2 °F

COMMON CONVERSIONSCOMMON CONVERSIONS°°F F °°C C -40-40 -40-40 00 -18-18 3232 0 0 5050 10 10 6161 16 16 8282 28 28 98.698.6 3737 104104 40 40

To estimate: Assume 1°C°C equals 2°F°F

• Sun warms ground• Ground warms adjacent air via conduction• Convection (thermals) occur and transfer heat upward• Lag to Maximum temperature

• Type of surface• Bodies of Water• Cloud cover• Wind

DAYTIME WARMINGDAYTIME WARMING

DAYTIME WARMINGDAYTIME WARMING

Fig. 3.2, p. 64

DAYTIME MIXINGDAYTIME MIXING

• Ground cools by radiational cooling• Better radiator and thus cools faster

• Inversions• Colder Air near surface

• Factors for colder conditions• Length of night• Cloud-free (not re-radiated back)• Windless (i.e., no mixing)• Dry - Moist nights are warmer due to released latent heat from condensation and IR warming

• Lag until coldest Temperature

NIGHTTIME COOLINGNIGHTTIME COOLING


Fig. 3.7, p. 69

NIGHT TIME MIXINGNIGHT TIME MIXING

Fig. 3.8, p. 70



FROST PROTECTIONFROST PROTECTION



•Each day resembles mini-season•Warming-Cooling Cycle•Maximum solar energy at noon

DIURNAL TEMPERATURESDIURNAL TEMPERATURES

CONTROLS ON TEMPERATURECONTROLS ON TEMPERATURE• Solar Insolation– Date– Time– Latitude– Exposure (wind, humidity)

• Geographic– Land– Water

• Oceanic– Currents

• Topography– Elevation

NORTH versus SOUTHNORTH versus SOUTHLand masses dominate

the Northern Hemisphere.

Oceans dominatethe Southern Hemisphere.

LAND vs. SEA LAND vs. SEA (July Temperatures)

• Land masses cause more temperature variations.• Oceans keep temperatures more moderate.

EXTREME TEMPERATURESEXTREME TEMPERATURES• The hottest place in the world is Dallol,

Ethiopia.• Average daily maximum temperature exceeded

100°F during every month of the year, except December and January.• Daily maximum often exceeds 120°F.• Average annual temperature 94°F.

Fig. 3.5, p. 67

EXTREME TEMPERATURESEXTREME TEMPERATURES• The coldest regions– Continental United States• Northern Great Plains and northern Maine.

– North America• Yukon and Northwest Territories of Canada.

– World• Antarctica• Average July (winter) is –74°F.• Mean annual temperature is –57°F.

Fig. 3.10, p. 72

DAILY TEMPERATURESDAILY TEMPERATURES• Daily Temperature Variations– Diurnal temperature range– Largest diurnal range of temperature• High Deserts: Dry air, cloud-free, little water

vapor – Clouds = Large affect on the daily temperature range– Locations near large bodies of water typically have

smaller diurnal temperature ranges

DEGREE DAYSDEGREE DAYS• DD = (Average Daily Temperature) - Base Temperature

• Summed through the year

• Heating Degree Days (HDD) if Negative (i.e., < 65°F)

• Need to use your heater

• Cooling Degree Days (CDD) if Positive (i.e., > 65°F)

• Need to use air conditioning

• Growing Degree Days (GDD)

• 60 – Cotton, Rice

• 50 - Beans, Corn, Grapes

• 40 – Peas, Wheat

MEAN COOLING DEGREE DAYSMEAN COOLING DEGREE DAYS

MEAN HEATING DEGREE DAYSMEAN HEATING DEGREE DAYS

Grapes & DEGREE DAYSGrapes & DEGREE DAYS

• Base 50 degreesBase 50 degrees

• Seasonal TotalSeasonal Total

• < 2500 - Chardonnay, Pinot Noir and White Riesling < 2500 - Chardonnay, Pinot Noir and White Riesling

• 2500 – 3000 - Chenin Blanc, Cabernet Sauvignon and Gamay 2500 – 3000 - Chenin Blanc, Cabernet Sauvignon and Gamay

• 3000 – 3500 – Zinfandel3000 – 3500 – Zinfandel

• 3500 – 4000 – Dessert winds, table and raisin grapes 3500 – 4000 – Dessert winds, table and raisin grapes

• > 4000 – Thompson Seedless> 4000 – Thompson Seedless

WIND CHILLWIND CHILL• Combination of Temperature and Wind• “Feels like” temperature on skin human

THERMOMETER TypesTHERMOMETER Types• Liquid in Glass

http://www.theodoregray.com/PeriodicTableDisplay/Samples/080.2/index.s15.html

THERMOMETER TypesTHERMOMETER Types• Liquid in Glass

• Maximum

• Minimum

THERMOMETER TypesTHERMOMETER Types• BiMetal Strips

•Thermograph

THERMOMETER TypesTHERMOMETER Types•Thermistor

• Change in Electrical Resistance

THERMOMETER TypesTHERMOMETER Types•Radiometer

• Measures longwave radiation (i.e., infrared)

THERMOMETER TypesTHERMOMETER Types•Radiosonde

Fig. 3.18, p. 81

HUMIDITYHUMIDITY

Review: PHASE TRANSITIONSWater in the atmosphere has gaseous, liquid Water in the atmosphere has gaseous, liquid and solid phasesand solid phases

Earth’s Water CycleEarth’s Water Cycle

SATURATIONSATURATION

When Rate of Evaporation = Rate of Condensation

SATURATIONSATURATION• Saturation: Rate of Evaporation = Rate of CondensationRate of Evaporation = Rate of Condensation. – To compensate there’s condensation• Cloud formation and/or Precipitation

• Higher temperatures = higher rate of evaporation.– Therefore more water vapor is needed to achieve

equilibrium.

Thus saturation is temperature dependent.

Humidity MeasuresHumidity Measures• Dew Point temperature– Temperature to which air must be cooled for

saturation (and thus condensation) to occur

• Wet-Bulb temperature– Uses evaporatively cooled temperature compared to

dry bulb temperature

• Vapor Pressure– Pressure due to water molecules alone

PARTIAL PRESSURESPARTIAL PRESSURESTotal Pressure = PN2+ PO2 + PAr + PH20 + PCO2 + …

Vapor Pressure:Pressure due towater molecules alone

If the total pressurewere ~ 1000 mb,PN2 ~ 780 mb 78%

PO2 ~ 210 mb 21%

PH20 ~ 10 mb 1%

JANUARY WATER VAPOR JANUARY WATER VAPOR (mb)(mb)

JULY WATER VAPOR JULY WATER VAPOR (mb)(mb)

RELATIVE HUMIDITYRELATIVE HUMIDITYRelative Humidity (RH) = water vapor content x100

water vapor capacityImportant: Only a measure of how close air is to becoming saturated, NOT amount of water vapor.

• If RH = 100%, then the air is saturated and condensation occurs.

• If water vapor content or temperature changes, so does Relative Humidity.

• With a constant water vapor content, cooling the air raises RH; heating the air lowers the RH.

TEMPERATURE vs. RHTEMPERATURE vs. RH• Highest RH normally early morning• Lowest in the afternoon.• Temperature change = saturation vapor pressure change.

Polar Air Temp=28°

DP=28° RH=100%

Desert Air Temp=95°

DP=41° RH=16%

POLAR AIR vs. DESERT AIRPOLAR AIR vs. DESERT AIR

Inside Air vs. Outside AirInside Air vs. Outside Air

Summertime Relative HumiditySummertime Relative Humidity

WEATHER EXTREMES ANDWEATHER EXTREMES ANDHUMAN DISCOMFORTHUMAN DISCOMFORT

• Extreme Dew Points– Highest Td in the world: Middle East near large

bodies of extremely warm water• Red Sea: surface temperature of 98°F • Sharjah, United Arab Emirates, Td 93°F

• Dhahran, Saudi Arabia, Td 95°F

Fig. 3.21, p. 83

Myth: 95° and 95% RH)Myth: 95° and 95% RH)

WEATHER EXTREMES ANDWEATHER EXTREMES ANDHUMAN DISCOMFOHUMAN DISCOMFORTRT

• “It’s Not the Heat, It’s the Humidity”– Both the air temperature and relative humidity

are high and the air is nearly saturated, body moisture does not readily evaporate

– Less evaporation means less cooling, meaning we feel warmer

WEATHER EXTREMES ANDWEATHER EXTREMES ANDHUMAN DISCOMFORTHUMAN DISCOMFORT

• The Heat Index– The index combines air temperature with relative

humidity to determine an apparent temperature– What the air temperature “feels like” to the

average person for various combinations of air temperature and relative humidity

HEAT INDEXHEAT INDEX• Combination of Temperature and Relative Humidity• Effective cooling of body

Humid Air vs. Dry AirHumid Air vs. Dry Air• Which weighs more?– Humid air is lighter (less dense) than dry air• Molecule of water vapor (H2O) weighs 18 atomic units

• Molecule of either nitrogen (N2=28 au) or oxygen (O2=32 au).

HUMIDITY INSTRUMENTSHUMIDITY INSTRUMENTS• Relative Humidity– Sling psychrometer– Hygrometer• Hair • Electrical• Dew point

– Satellite Sensors

SLING PSYCHROMETERSLING PSYCHROMETER

Wick

Dry Bulb Thermometer

Wet Bulb Thermometer

Gives Wet Bulb Temperature

HAIR HYGROMETERHAIR HYGROMETER

• “Bad hair day”

As RH increase Hair length Increases

ELECTRONIC MEASUREMENTSELECTRONIC MEASUREMENTS

• Measuring Dew-Point Temperature

• Cool a mirror until condensation

• Optical detect water

•Measuring Humidity

• Electric current through ceramic material

• Change in Resistance = Change in Humidity

SATELLITE MEASUREMENTSSATELLITE MEASUREMENTS• Water Vapor Imagery

Hyperthermia Deaths Hyperthermia Deaths of Children in Vehiclesof Children in Vehicles

Jan Null, CCMJan Null, CCM

San Francisco State UniversitySan Francisco State UniversitySafeKids USASafeKids USA

2010 Headlines2010 Headlines

Twins die trapped inside a hot vehicleTwins die trapped inside a hot vehicle

Funeral today for girl found dead in hot vanFuneral today for girl found dead in hot van

Baby left in truck all day diesBaby left in truck all day dies

Toddler dies after being left in hot carToddler dies after being left in hot car

Baby daughter dies after dad forgets her inside his carBaby daughter dies after dad forgets her inside his car

Son dies after 9 hours in carSon dies after 9 hours in car

… …. And 43 more similar headlines in 2010 ….. And 43 more similar headlines in 2010 ….

4949

How Many?How Many?

494+494+

1998-2010<1 Airbag death/yr38 Hyperthermia/yr

1991-199721 Airbag Deaths/yr11 Hyperthermia/yr

What Has Changed?What Has Changed?

What Circumstances?What Circumstances?

44% of “forgotten” children were to have been dropped off childcare/preschool .44% of “forgotten” children were to have been dropped off childcare/preschool .

How Old?How Old?

Average Age = 21 monthsAverage Age = 21 months

When?When?

Current LawsCurrent Laws

More states have laws against leaving pets in vehicles

What is Hyperthermia?What is Hyperthermia? Child’s body less capable of cooling itselfChild’s body less capable of cooling itself A child’s body temperature rises 3 to 5 A child’s body temperature rises 3 to 5 times faster than an adult’stimes faster than an adult’s Heat StrokeHeat Stroke

Cooling system is overwhelmed at 104 ° FCooling system is overwhelmed at 104 ° F SymptomsSymptoms

Stops perspiring, red dry skin, faintness, Stops perspiring, red dry skin, faintness, staggering, strong and rapid pulse; staggering, strong and rapid pulse; possible delirium or comapossible delirium or coma

Death at 107 ° FDeath at 107 ° F

My Involvement?My Involvement?

July 2001, San Jose CaliforniaJuly 2001, San Jose California Kyle Patrick Gilbert (5 mo)Kyle Patrick Gilbert (5 mo) Left by 19-year-old fatherLeft by 19-year-old father

Media asked “How hot did it get in the car?”Media asked “How hot did it get in the car?”

Only study was by LA State Med. Soc. for only Only study was by LA State Med. Soc. for only a single 93° daya single 93° day

How Hot? How Fast?How Hot? How Fast?

Summer 2002 observational studySummer 2002 observational study

16 study days 16 study days Outside air temperatures from 72 ° - 96° FOutside air temperatures from 72 ° - 96° F

On two days, measurements were also made On two days, measurements were also made with the windows “cracked” 1.5 incheswith the windows “cracked” 1.5 inches

How Do Cars Get Hot?How Do Cars Get Hot?Incoming Shortwave Solar Radiation Warms Interior Objects

Air and Windows are Transparent to SunlightAir and Windows are Transparent to Sunlight

Outgoing Longwave Radiation Heats the Air



An 80° DayAn 80° Day







Vehicle Heating SummaryVehicle Heating Summary

Nearly half of temperature rise in 10 minutesNearly half of temperature rise in 10 minutes 80% in first 30 minutes80% in first 30 minutes Temperatures plateau 45-50° above ambientTemperatures plateau 45-50° above ambient

“ “Cracking” windows has minimal effectCracking” windows has minimal effect

Dark cars NOT necessarily worse than white carsDark cars NOT necessarily worse than white cars

Published: Published: PediatricsPediatrics, 2005, 2005 Updated on the Internet Updated on the Internet

SAFETY RECOMMENDATIONSSAFETY RECOMMENDATIONS

NEVER LEAVE A CHILD UNATTENDED IN A NEVER LEAVE A CHILD UNATTENDED IN A VEHICLE. NOT EVEN FOR A MINUTE!VEHICLE. NOT EVEN FOR A MINUTE!IF YOU SEE A CHILD UNATTENDED IN A HOT IF YOU SEE A CHILD UNATTENDED IN A HOT VEHICLE CALL 9-1-1.VEHICLE CALL 9-1-1.Be sure that all occupants leave the vehicle Be sure that all occupants leave the vehicle when unloading.when unloading.Teach your children that vehicles are never to Teach your children that vehicles are never to be used as a play area. be used as a play area. Have a plan that your childcare provider will call Have a plan that your childcare provider will call you if your child does not show up for school. you if your child does not show up for school.

SAFETY RECOMMENDATIONSSAFETY RECOMMENDATIONS

Midterm ReviewMidterm Review• Divide into 6 groups of approx. 8 students• Choose a spokesperson• Group w/ most points gets 5 extra credit– Next gets 4 points, etc.

• Sheet of paper with last names and G roup #

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February 15 (Week 4) Term Paper Topics Isopleths HW#4 Weather Review