ATMO 336 1st EditionLecture 13Outline of Last Lecture I. Summary of how water behaves based on relative humidityII. Energy transfera. Radiationb. Conduction c. Convectioni. Dry convection (natural dry convection and forced dry convection)ii. Moist convectionIII.Outline of Current Lecture II. Temp, humidity, wind, and human comforta. Core tempb. Thermalneutral zonec. ThermoregulationIII. Biological control systemsa. Human body response to cold core tempb. Human body respnse to warm core tempIV. HypothermiaV. HyperthermiaVI. Influence of weather conditions on heat lossa. Heat indexb. Wind chill indexVII. Clouds and their formationVIII. Why does rising parcel of air cool?a. Air pressure surrounding parcel is different than air pressure in parcel= pressure forces on the parcel surface are not balanced = forced to change shape (expand or condense in volume)Current LectureTemperature humidity, wind, and human comfort, clouds, why does rising air cool?- Temperature humidity, wind, and human comforto Under high temperature and high humidity= difficult for body to remove excess heato Thermoregulation= profess when human body regulates internal heat generation and external eat exchange so that its core temp. varies no more than 2 degrees celcius from its average 37 degrees Celcius.These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.o Core= vital organs .if core temp outside of this, essential life functions do not work properlyo Thermalneutral zone= when air temperature is between 20degrees C and 25 degrees C (66-77 degrees F), with little wind and moderate relative humidity Body can maintain core temp at these condiions- Biological control systemso = regulators of libing thingso homeostasis= stable operation of psyciological activities (over half of all energy from food and other sources leave body as heat)o enzyme biochemical reactions most efficient at 98 degrees F- human body’s responses to cold core tempo 1. Increase internal heat production by shiveringo reduce heat loss by casoconstriction (constricted blood vessles)= reduces blood and heatflow (lower legs cool down which reduces heat loss). Also reduces surface area of warm blood that is in contact with outside air (in extreme cases= frostbite)- human body’s responses to warm core tempo sweating= body cooled by evaporation. Best way to lose heat. o Increase heat loos by vasodilation (widening of blood vessles) exposes warm blood to outside air over larger surface area (this only worls if air temp is lower than body temp) if air temp warmer than body temp, vasodilation occurs- Both of these reactions programmed by brain’s hypothalamus from theroreceptorso Thermo regulation and other forms of homeostasis maintain within an acceptable range- Hypothermia= human core temp drops below 35 degrees C (95 degrees F)o Shivering more violent and uncrontrollable, speaking befcomes apathetic and lethargic. o If droping furher beneath 32 degrees, enxyme activity further slows= unconsciousness and unresponsive.o Death may occure under 24 degrees C because heart rhythm becomes uncontrollably irregula (ventricular fibrillation) or uncontrollably halted (cardiac arrest)o Only 3 degrees C drop in core temp greatly impairs body’s ability to regulate core temp.- Hyperthermia= conditions hwere temperatures clibs abot 102 degrees F (39 degrees c) or higher.o 2 stages: heat exhaustion and heat cramps( due to loss of sodium and potassium salts (electrolytes) “wandering cramp” throughout the muscle. core temp reaches 41 degrees C, enzymes begin to fail and thermoregulatory mechanisms breakdown. Heatstroke follows- Influence of weather conditions on heat losso Hot conditions, high humidity reduces the rate of heat losee because it slows down rate of evaporationo Heat index= take into account the decreasing rate ofheat loss due to the combination of high temperature and high humidity (cannot be measured with thermometer This is also a number related to the computed and/or measured net rate of heat loss from the human body for a give combination of air temperature and relativ ehumidit The higher the heat index, the slower the rate or heat loss from the “average” human body- Wind chill index= dangerous comination of cold and high windso Is a number related to the rate of heat loss from the human body for a given combination of air temp.and windspeed. o The lower the windchill equivalent temp. the faster the rate of heat loss from the “average” human body.o Windchill will never be higher than air temperatureo Windchill equivalent computed for exposed skino Frost bite first occurs of extremities of bodies first because bloodflow to these areas is reduced to conserve body heat for vital organsClouds- Clouds composed of tiny droplets of liquid water an/ or ice crystals which are really aerosols and are NOT water vapor, which is an invisible gaso Important in regulating climate of eartho Formation= vast quatities of heat released o Result from net condensation( or deposition)o Cloud condensation nuclei= microscopic aerosol particles, such as dust smoke and salto Form as air rises and cools (as air cools, relative humidity increases since saturation mixing ratio decreases as temp gets lower) Relative humidity= 100%, condensation occurs and cloud formation and latent heat releasedo Warmer air surrounded by cooler air is buyant because it is less dense (weighs less) than surrounding cooler air and thus, this warmer air accelerates upward (thunderstorms andhurricans)Why does rising parcels of air cool?- If the air pressure surrounding the parcel is different than the air pressure inside the parcel, thenthe pressure forces on the parcel surface are not balanced = forced to change shape (volume)o Air pressure outside greater than airpressure inside, then parcel is squeeze andcompressedo If air pessure outside less than air pressure inside, then parcel will expando When air parcel rises in atmosphere, it must expand, thus number density of air inparcel decreaseso- key pointso when air parcels move in the atmosphere, their sizes (volumes) change in response tothe changing air pressure surrounding them. Air pressure inside parcels always equal toair pressure surrounding parcel. This is NOT the case for temp and number density (airtemp and density DO NOT have to equal temp and number