ATMO 336 1st edition Lecture 30 Outline of Last Lecture II. Climate introductiona. Strongest influencing factos= latitude and solar energy receivedIII. Seasons (astronomical)a. Changes in intensity of sunshine receivedb. Changes in daylight lengthc. Earths orbit and axis of rotationd. EquinoxesIV. Intensity of sunshine- solar angle at noona. Depends on latitudeb. Solar declinationc. TropicsV. Length of dayI. Outline of Current Lecture VI. Factors affecting climate changea. Latitudeb. Elevationc. Proximity to large bodies of waterd. Ocean currentse. Soil moisturef. Humidityg. Cloud coverVII. Nature of the surfaceVIII. Anthropogenic influencesIX. Daily temperature variation in desert climatesCurrent Lecture- Factors that affect a regions climate- Latitudeo Most important climate control, due to the effect it has on the amount of solar radiation reaching the earths surfaceo Largest seasonal changes in arctic and Antarctic regions due to the largest changes in solar radiation receivedThese 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 In the intertropical convergence zone, subtropical highs and the polar fronts move with seasons= reason for why places on earth experience wet and dry seasons over a source of the year (pronounced in tropics) ITCZ= located directly over head means wet seasons, opposite for dry seasonso In Tucson: In the wintertime, we are sometimes affected by the polar front, i.e., when troughs are able to dig as far south as Tucson, and this gives us some winter rains. In the summertime, the subtropical high moves to our north, which allows tropical air to move in, and gives us monsoon season rains.- Elevationo Influences air temperature (since air temp decreases with height). o Also determine whether precipitation falls in form of rain or snow Mountain slopes force air to rise which favors clouds and precipitationo Daily temp extremes between day and night are typically greater at higher elevations Less atmosphere= easier for suns energy to reach the surface and heat it Less atmosphere means fewer greenhouse gases and weaker greenhouse effect, so the ground surface cools more rapidlyo Proximity to mountain ranges is important for prevailing air flow (affect climate and possibly stimulate cyclone formation) Orographic clouds and precipitation form on windward facing slopes- Proximity to large bodies of watero Areas near large bodies of water mean more constant temperatures between summer and winter, and day and nighto Three reasons for moderate temps: Solar radiation reaching land surface absorbed by thin layer of soil and topsoil heats very rapidly. Solar radiation that hits water absorbed over great depth= water surface temp changes slowly compared to land surface which means water is able to circulate (long time to warm, long time to cool during night) Energy absorbed by oceans is used to evaporate water. Most energy that goes toland surface is used to raising temp of the ground Water has high specific heat (amount of energy that must be absorbed by one gram of a substance to raise its temp by 1 degree C)o On longer time scales, oceans can slow down the rate of warming that may come about due to increases in greenhouse gases- Ocean currentso Currents that have northward or southward component (i.e. gulf stream in north atlanticor Humboldt current off south America) effectively exchange heat between low and highaltitudes- Soil moistureo Location with dry surface (deserts) will have larger temperature differences between dayan night compared to place with wetter surfaces- Humidityo Most important influence of water vapor in atmosphere on surface temp at nighto Higher amounts of water vapor tend to stay warmer since water vapor is a greenhouse gas Water vapor absorbs some radiation energy form sun, keeping the ground surface coolero High humidity= causes aerosol particles to swell so they absorb and reflect more radiation form sun before it reaches the ground (this is why Tucson tends to have relatively large temperature swings between day and night compared to location with high relative humidity)- Local topographyo Variations in slope affects amounts of absorbed sunlight, exposure to winds, and runoffo Southward facing slopes in northern hemisphere= more direct sunshine and more heating than northern facing slopes  (Tucson= saguaro cacti most dense on south slopes and can be found at higher altitudes on south slops than north)- cloud covero clouds are cooling influence during dayo reflect solar radiation o influence warming at night because they emit radiationo high cloud cover areas have less temp variations- nature of the surfaceo shaded surfaces (under trees) do not get as hot as surfaces under direct sunshineo vegetated lands do not eat as rapidly as sand or rock due to energy input that is used by the plants to grow and transpireo reflectance of surface important (albedo effect)o wet surfaces heat and cool more slowly that dry surfaces- anthropogenic influenceso places where forests replaces with crops= surface has less moisture availible for evaporation thus, having higher temperatures than forested region opposite effect for dry lands that are converted to irrigated landso heat islands= warmer than surrounding countryside due to: building materials in cities and absorb solar radiation better than soils and vegetation human activities generate heat which additionally warms cities- daily temperature variation in desert climateso desert regions have large temp changes between daytime high and nighttime low compared to other climes. Reasons why: continental location (far from oceans) usually clear skies (lack of clouds) dry atmosphere (low dewpoint and low relative humidity) relatively high elevation (compared with many other major