Slide 1Slide 2Slide 3QuestionsSlide 5Slide 6Slide 7Slide 8Slide 9Slide 11Slide 13Slide 14Slide 15CondensationSlide 17Zonal Mean Cloud Effective Radius (M. D. King, S. Platnick et al. – NASA GSFC)Clouds and radiationClouds and day to day temperaturesWhich day would be warmer?Which evening would be warmer?Slide 23Low and High cloudsClouds and climateChanges in cloudsSlide 28Slide 29Slide 30Slide 31Slide 32Slide 33Slide 34Slide 35Slide 36Slide 37Slide 38Slide 39Slide 40Slide 41Slide 42Slide 43Slide 44Slide 45Slide 46Slide 47Slide 48Slide 49What percentage of the Sun’s radiation is absorbed by the Earth’s surface?What percentage of the Sun’s radiation is absorbed by the Earth’s atmosphere?What percentage of the sun’s radiation is reflected out to space?If the Sun’s radiation was to increase by 10%, how would the energy gained by the earth’s surface change?If the Sun’s radiation was to increase by 10%, how would the energy emitted by greenhouse gases change?If the Sun’s radiation was to increase by 10% the energySlide 56Slide 57MET 112 Global Climate Change -CLOUDS and CLIMATEProf. Menglin JinDepartment of Meteorology, San Jose State UniversityOutlineClouds FormationClouds Climatology Clouds and the Radiation BudgetClouds by Christina RossettiWhite sheep, white sheep,On a blue hill,When the wind stopsYou all stand stillWhen the wind blowsYou walk away slow.White sheep, white sheep,Where do you go?A good repository of cloud photos in various categories can be foundat www.cloudappreciationsociety.org/galleryQuestionsQuestionsWhat role do clouds play on the Earth’s climate?What would happen to our climate if clouds were to increase/decrease?Earth System Water Cycle6 MET 112 Global Climate MET 112 Global Climate ChangeChangeClouds are formed when air containing water vapor is cooled below a critical temperature called the dew point and the resulting moisture condenses into droplets on microscopic dust particles (condensation nuclei) in the atmosphere. Clouds FormationA visible mass of liquid water droplets suspended in the atmosphere above Earth's surface. http://earthobservatory.nasa.gov/Library/glossary.php3Clouds can form along warm and cold fronts, where air flows up the side of the mountain and cools as it rises higher into the atmosphere, and when warm air blows over a colder surface, such as a cool body of water.Water in the atmosphereWater in the atmosphereDefinitions:–Evaporation:–Condensation:–Precipitation:Process where a liquid changes into a gasProcess where a liquid changes into a gasAny liquid or solid water that Any liquid or solid water that falls from the atmosphere to the falls from the atmosphere to the ground. (i.e. RAIN!)ground. (i.e. RAIN!)Process where a gas changes into a liquidProcess where a gas changes into a liquidWater freely Water freely evaporating and evaporating and condensingcondensingSince more water Since more water molecules are molecules are evaporating than evaporating than condensing, then net condensing, then net evaporation is evaporation is occurring.occurring.Lid on:Lid on:The humidity is now The humidity is now 100%100%Lid on:Lid on:Now, evaporation and Now, evaporation and condensation are equal. condensation are equal. The air above water is The air above water is now called ‘saturated’.now called ‘saturated’.The humidity is now The humidity is now 100%100%CondensationCondensationThe process by which water vapor changes to a cloud droplet Water vapor molecules may ‘stick’ to condensation nuclei and grow (billions) to eventually form cloud droplet.Examples of condensation nuclei include:a.a. DustDustb.b. SaltSaltc.c. SmokeSmoke Condensation occurs primarily as temperature cools:-colder the molecules more likely they are to ‘stick’ to other moleculesZonal Mean Cloud Effective Radius(M. D. King, S. Platnick et al. – NASA GSFC)July 2006 (Collection 5)AquaClouds and radiationClouds and radiationCloud - Climate InteractionsCloud - Climate InteractionsAlbedo effect - COOLINGAlbedo effect - COOLINGClouds reflect incoming solar radiation. Clouds reflect incoming solar radiation. The cloud droplet size and total water content The cloud droplet size and total water content determine the overall reflectivity. determine the overall reflectivity. Greenhouse effect - WARMINGGreenhouse effect - WARMINGClouds are good absorbers (and emitters) of long Clouds are good absorbers (and emitters) of long wave (infrared) radiation.wave (infrared) radiation.Clouds and day to day Clouds and day to day temperaturestemperaturesImagine that you are going camping in the Sierras Imagine that you are going camping in the Sierras with your friends. On the first day (and evening) it with your friends. On the first day (and evening) it is cloudy, while on the second day (and evening) it is cloudy, while on the second day (and evening) it is clear. Based on this information alone:is clear. Based on this information alone:Which day would be warmer?Which day would be warmer?Which evening would be warmer?Which evening would be warmer?Explain your answers.Explain your answers.Which day would be warmer?1. First day (clear)2. Second day (cloudy)3. Both the same0 of 70Which evening would be warmer?1. First day (clear)2. Second day (cloudy)3. Both the same0 of 70Clouds typesLow and High cloudsLow and High cloudsConsider two types of clouds:Consider two types of clouds:1.1.Low levels clouds Low levels clouds 2.2.High levels cloudsHigh levels cloudsQ: How is the Earth’s surface energy budget Q: How is the Earth’s surface energy budget different for low clouds compared to high different for low clouds compared to high clouds?clouds?Clouds and climateClouds and climateCloud A: Low level, (dark, thick)Cloud A: Low level, (dark, thick)Cloud B: High level, light Cloud B: High level, light (sub visible or thin)(sub visible or thin)Excellent reflector of incoming radiation; good absorber/emitter of infrared radiationFair/poor reflector of incoming radiation; good/excellent absorber/emitter of infrared radiationSo, clouds both warm and cool the earth. Overall, though, clouds act to cool the earthChanges in cloudsChanges in cloudsIncreases in low level clouds will:Increases in low level clouds will:– Increases in high level clouds will:Increases in high level clouds will:Changes in cloudsChanges in cloudsIncreases in low level clouds will:Increases in low level clouds