Solar and Earth: Layers of the Atmosphere PDF

Solar and Earth ABE 311 Layers of the atmosphere our atmosphere would be only as thick as the onion’s skin allows life to exist on Earth by protecting us from the harmful bits of the Sun’s radiation. also keeping the Earth warm, through a process known as the Greenhouse Eff...

Solar and Earth ABE 311 Layers of the atmosphere our atmosphere would be only as thick as the onion’s skin allows life to exist on Earth by protecting us from the harmful bits of the Sun’s radiation. also keeping the Earth warm, through a process known as the Greenhouse Effect. contains the air we breathe and is a major part of the water cycle. atmosphere is split into 4 main layers based on temperature.  Layers of the atmosphere The aurora, the Northern Lights and Temperatures can vary from between Southern Lights, occur here 500 and 2000°C or higher This is the coldest layer (-100degC) of the Most meteors burn up in this layer atmosphere and the air at this height is far too thin to breathe temperatures actually get warmer the contains the ozone layer, which absorbs higher you go. high energy UV light converting it into heat. Most clouds appear in the troposphere We live in this part because 99% of the atmosphere’s water is As you get higher in this layer, the found there temperature gets colder.  - solar beam spreads over a greater area at higher latitudes and attenuation or beam Latitudinal distribution of incoming radiation depletion, by the atmosphere. maximum at the equator; minimum at the poles solar beam spreads over a greater area at higher latitudes and attenuation or beam depletion, by the atmosphere. Office of the Vice Chancellor for Research and Extension University of the Philippines Los Baños, College, Laguna, 4031 T: +63 of Office (049) the536 2354 Annex: +63 (049) 536 5326 Chancellor University Universityof the3604 F: +63 (049)of536 the Philippines Philippines Los Baños Los Baños, www.uplb.edu.ph | [email protected] College, Laguna, 4031 Philippines College, Los Baños, Laguna 4031 Philippines AGME 260 TROPICAL AGROMETEOROLOGY Radiative imbalance between equator and poles The ocean and atmosphere compensates such imbalance through fluid motion; Like a heat engine to equilibrate the earth system. Such is driven by the tropical latitudes. Malkus (1962) called the tropics as the “firebox” of the heat engine. General circulation of the athmosphere High and low pressure regions Cross-sectional view of the meridional circulation b/w the tropics and subtropics driven by heating in the equatorial regions and upward transport by deep convection in the tropics and sinking motion in the subtropics (Simpson, 1992) Cross-sectional view of the meridional circulation b/w the tropics and subtropics driven by heating in the equatorial regions  Global Air Currents and Climate Due to heating in the equatorial regions, there exist an upward transport by deep convection in the tropics and sinking motion in the subtropics (Simpson, 1992) Important distinction: Weather as short-term state of the atmosphere at a given time and place; for example, today, tomorrow, or the near future. Short-term weather fluctuations are caused by internal atmospheric instabilities rather than changes in solar output.  3. Defining the Tropics The region where the solar declination angle is Defining the tropics from +23.5° to -23.5° The region where the solar declination angle is from +23.5° to -23.5° Office of the Chancellor University ofofthe University Philippines the Philippines Los Baños Los Baños, www.uplb.edu.ph | [email protected] College, Laguna, 4031 Philippines College, Los Baños, Laguna 4031 Philippines AGME 260 TROPICAL AGROMETEOROLOGY The region of surplus radiation where annual solar The region of surplus radiation where annual input solar minus terrestrial output is positive, ± 35 input minus terrestrial output is positive, to 40° latitude ± 35 to 40° latitude Office of the Chancellor University ofofthe University Philippines the Philippines Los Baños Los Baños, www.uplb.edu.ph | [email protected] College, Laguna, 4031 Philippines College, Los Baños, Laguna 4031 Philippines AGME 260 TROPICAL AGROMETEOROLOGY The region of net upward motion and surface low pressure: + Net radiation sets air in upward motion and low pressure at the surface surrounded by sinking air and high pressure at the subtropics AKA Hadley Cell (in honor of George Hadley) The region where winds blow from the east The region where winds blow from the east ( ~ ( ~ ± 30° Lat). ± 30° Lat). Office of the Chancellor University ofofthe University Philippines the Philippines Los Baños Los Baños, www.uplb.edu.ph | [email protected] College, Laguna, 4031 Philippines College, Los Baños, Laguna 4031 Philippines AGME 260 TROPICAL AGROMETEOROLOGY  The easterly trade winds flow out of the subtropical high into The easterly trade winds the equatorial flowconverge trough; out of the at subtropical high into the equatorial the Intertropical trough;Convergence converge at the ZoneIntertropical Convergenceband (ITCZ) - an intermittent Zoneof(ITCZ) clouds- an in intermittent the lowband of clouds pressure in the belt or low pressure equatorial trough.belt or equatorial trough. Office of the Chancellor University ofofthe University Philippines the Philippines Los Baños Los Baños, www.uplb.edu.ph | [email protected] College, Laguna, 4031 Philippines College, Los Baños, Laguna 4031 Philippines AGME 260 TROPICAL AGROMETEOROLOGY The region where the annual range of temperature is less than or equal to the average daily range. The region better described by a wet and dry season rather than the four seasons of higher latitudes because annual rainfall varies much more from place to place than annual temperature. Latent Heating & Convective Cloud Distribution 5. Latent Heating & Convective Cloud Distribution most important method of method most important energy transfer; of energydominant transfer;source of energy fordominant circulationsource of energy for circulation Office of the Chancellor University ofofthe University Philippines the Philippines Los Baños Los Baños, www.uplb.edu.ph | [email protected] College, Laguna, 4031 Philippines College, Los Baños, Laguna 4031 Philippines AGME 260 TROPICAL AGROMETEOROLOGY  Latent heat is released to the atmosphere during condensation and precipitation. Latent heat is removed from the atmosphere during evaporation. Tropical oceans supply most of the moisture for convection. The strength and location of convection depends on various factors including surface fluxes of sensible heat, which may alter the stability of the atmosphere MeanMean Outgoing OutgoingLongwave Radiation Longwave Radiation (OLR)(OLR) 1979 - 1995 (Units in W/m2 ) 1979 - 1995 (Units in W/m2 ) (NOAA/NCEP) (NOAA/NCEP) TROPICAL CONTINENTS WESTERN PACIFIC OCEAN AND INDIAN OCEAN Blue Blue and redand red regions regions indicate indicate lowest lowest OLR as emitted OLRConvective by Deep as Clouds emitted by Deep Convective Clouds Annual Annualcycle ofcloud cycle of cloud tops tops Spatial and and Spatial temporal change temporal in in change these theseconvective convective areas areas and and upward transport motion upward leadmotion transport to dramatic lead tochanges dramaticin Office of the Chancellor the global changes in theclimate University ofofthe University Philippines the Philippines Los Baños Los Baños, College, Laguna, 4031 Philippines College, Los Baños, Laguna 4031 Philippines global climate.AGME 260 TROPICAL AGROMETEOROLOGY www.uplb.edu.ph | [email protected] Surface-Atmosphere Interactions Surface-Atmosphere - is an integral part of the transport Interactions of energy within and from the tropics. Ocean surface-atmosphere interactions - is an integral part are aofdominant of the transport component energy within and from the tropics. >> waterOcean havingsurface-atmosphere a larger heat capacity, the oceanic interactions areresponse to seasonal a dominant variations of solar component heating is>>smaller than compared water having to land a larger heat surfaces. capacity, the oceanic response to seasonal variations of solar heating is smaller than compared to land Oceans aresurfaces. then able to store heat during the summer and release it during the winter. Oceans are then able to store heat during the summer and release it during the The peak in oceanic winter.of heat to the poles occurs at low latitude. transport The peak in oceanic transport of heat to the poles occurs at low latitude. Office of the Chancellor University ofofthe University Philippines the Philippines Los Baños Los Baños, Annual MeanMean Annual Transport by by Transport Latitude LatitudeininPetawatts College, Laguna, 4031 Philippines (PW= 1015W)W) www.uplb.edu.ph | [email protected] Petawatts (PW= AGME 260 TROPICAL College, Los Baños, Laguna 4031 Philippines 1015 AGROMETEOROLOGY  Primarymode Primary modeofofinteraction interaction- -Evaporation Evaporation Windmomentum Wind momentumcauses causeswater watermovement movemente.g. e.g. Primary Tropical Tropical mode Cyclone Cyclone of interaction - Evaporation momentum Energyisiscauses Energy Wind gained gained from from water thewarm the movement warm ocean waters e.g. ocean waters throughlatent through latentheatheattransfer transfer Tropical Cyclone Winds Winds Energy is gained stir stir from the the ocean theocean surface, surface, warm ocean transfer waterstransfer through latent heat transfer momentumdownward, momentum downward,and andleave leaveaacool cool Winds stir the ocean surface, transfer momentum downward, and leave a cool anomalyanomaly anomaly (relatively (relatively (relatively low P region) lowPPregion) low region) Office Office ofChancellor of the the Chancellor University of University of University University the of thethe of Philippines the Philippines Philippines Philippines LosLos Los Baños, Los Baños, Baños Baños www.uplb.edu.ph | [email protected] www.uplb.edu.ph | [email protected] College, College, College, College, Laguna, Laguna, 40314031 Los Baños, Los Baños, Laguna Philippines Philippines Laguna 4031 4031 Philippines Philippines AGME AGME 260260 TROPICAL TROPICAL AGROMETEOROLOGY AGROMETEOROLOGY Critical Criticalsurface-atmosphere interactions surface-atmosphere interactions Office of the Chancellor University ofofthe University Philippines the Philippines Los Baños Los Baños, www.uplb.edu.ph | [email protected] College, Laguna, 4031 Philippines College, Los Baños, Laguna 4031 Philippines AGME 260 TROPICAL AGROMETEOROLOGY Atmospheric Structure 6. Atmospheric Structure Office of the Chancellor University ofofthe University Philippines the Philippines Los Baños Los Baños, www.uplb.edu.ph | [email protected] College, Laguna, 4031 Philippines College, Los Baños, Laguna 4031 Philippines AGME 260 TROPICAL AGROMETEOROLOGY  The troposphere is heated from below by latent heat, longwave radiation, and sensible heat. The tropics experience surplus heating and vertical expansion of the troposphere in response to that heating. In addition, deep tropical clouds transfer latent heat high in the atmosphere. The result is that the tropopause is highest in the tropics. The average height of the tropical tropopause (18 km) is ~ 7 km higher than the average tropopause height at the poles. Seasonal and Geographic Distribution of Temperature 7. Seasonal and Geographic Distribution of Temperature  Office of the Chancellor University ofofthe University Philippines the Philippines Los Baños Los Baños, www.uplb.edu.ph | [email protected] College, Laguna, 4031 Philippines College, Los Baños, Laguna 4031 Philippines AGME 260 TROPICAL AGROMETEOROLOGY Annual AnnualTemperature Range Temperature Range (°C) (°C) Tropics: lowest Tropics: rangerange lowest (< 1.5°C) near near (< 1.5°C) equatorial regions equatorial Midcontinental regions Africa and AustraliaAfrica Midcontinental - highest andrange in the- highest Australia subtropics range in the subtropics Australia: highest range of the tropical continental regions (21-32degC) Office of the Chancellor Australia: highest range of the tropical University ofofthe University Philippines the Philippines AGMEcontinental Los Baños Los Baños, College, Laguna, 4031 Philippines College, Los Baños, Laguna 4031 Philippines regions. www.uplb.edu.ph | [email protected] 260 TROPICAL AGROMETEOROLOGY Diurnal Temperature Diurnal Temperature Variability Variability Factors affecting mean diurnal temperature range 1) Humidity - Temperature variation is more moderate in humid environments because water vapor is a good absorber and emitter of longwave radiation. Water vapor also absorbs in the near infrared part of the solar radiation, which reduces the energy reaching the surface during the daytime. Therefore, daily maximum temperatures are lower in humid environments and higher in dry environments. 2) Cloudiness - Clouds are good absorbers and emitters of longwave radiation and good reflectors of sunlight (shortwave radiation) therefore cloudiness leads to cooler days and warmer nights and a smaller diurnal temperature range. 3) Wind speed - during windy conditions air with different temperatures is more easily mixed and helps to moderate the temperature range. 4) Albedo - The diurnal temperature range is influenced by the albedo in the same manner as the annual cycle. Highly reflective surfaces are cooler than surfaces with low reflectivity. 5) Elevation - Mountain areas are warmed earlier than the valleys below and cool more rapidly after sunset. The difference in heating causes valley (upslope) and mountain (downslope) breezes, respectively. Extreme temperatures Extreme recorded temperatures recorded in the tropics in the tropics Office of the Chancellor University ofofthe University Philippines the Philippines Los Baños Los Baños, www.uplb.edu.ph | [email protected] Spatial and temporal 8. Spatial scales scales and temporal Office of the Chancellor University ofofthe University Philippines the Philippines Los Baños Los Baños, www.uplb.edu.ph | [email protected] College, Laguna, 4031 Philippines College, Los Baños, Laguna 4031 Philippines AGME 260 TROPICAL AGROMETEOROLOGY Motion and momentum transfer occur at various scales simultaneously. Instabilities in the atmosphere and ocean are created by gradients of temperature, winds, humidity, and SSTs. Weather and climate phenomena are responses to these instabilities. Scales of atmospheric motion range from short length and time scales of friction and turbulent motion to the decadal and planetary scale circulations. Some occupy a range of scales. Smaller scale features can occur within a larger scale circulation: tropical cyclones consisting numerous thunderstorms; tropical cyclones spawned within intraseasonal MJO both can be modulated by the interannual ENSO