NREM 301 Forest Ecology & Soils Day 30 December 4, 2008 Answer Test Questions Finish Climate Discussion Take-Home Test Due Dec 11 5 pm No Final Exam Lab Today Finish & e-mail all materials to Dick Class discussion of plans for the site Dust Storm Northern China
Short waves high energy Long waves low energy Radiant Energy 99% solar radiation falls between.25 2.5 microns Max rate at: 0.5 microns 99% - earth radiation falls between 3.5 10 microns Max rate at: 10 microns Solar radiation = shortwave Terrestrial = longwave Page 155, textbook
41% 50% Absorption Transmission Reflection Describe the importance of the absorption, reflection and transmission spectra for a cottonwood leaf. What does that mean for the leaf?
Group Activity How does this graph explain the greenhouse effect? Greenhouse Effect Water Vapor Effect Global Warming Atmospheric Window 8-13 microns Clouds
What is the significance of water vapor absorptivity in the climates of Georgia and Arizona (both at about the same latitude)? Phoenix X Clear Sky Very Low Humidity Little Heat Trapped Hot Days Cool Nights X Ames More Clouds High Humidity Lots of Heat Trapped Hot Days & Nights X Atlanta
Group Exercise Albedo reflection Which one of each set below reflects more radiation: Fresh snow vs old snow Dark soil vs light colored soil Wet soil vs dry soil Deciduous Forest vs Grassland Deciduous forest vs conifer forest Lake surface when the sun is near the horizon vs nearly overhead
Air Circulation Convection Cell Sunny Calm Day Summer Conditions Advection - wind Subsidence Convection Advection - wind Large lake cool Land - warm When radiation is absorbed it is converted to sensible heat that can be conducted or convected or reradiated as radiant energy
Develop a convection cell between the lake and forest At night
Why do they spray water on frost sensitive crops on a night when air temp may freeze? Sensible vs Latent Heat Need 1 Calorie to raise temperature of 1 gram of water 1 degree C If the same amount of radiation were absorbed by a dry & wet soil which would have the higher temperature?
Convectional lifting What are the temperatures at 4,000 ft, 15,000 ft and sea level on the other side? Dry adiabatic lapse rate = 5.5 o /1,000 ft Moist adiabatic lapse rate = 3.0 o /1,000 ft Frontal lifting 5 F 15,000 ft Rain lost moisture Drops @ dry adiabatic lapse rate Orographic lifting 38 F 60 F Condensation Level 4,000 ft 87.5 F
Group Activity Draw a temperature profile for 6 am and 2 pm on a warm sunny May day over a bare field and a forest 6 am 2pm 6 am 2 pm Height Bare Soil Temperature Depth Depth Height
Open Group Activity Radiating Surface Forest Note: 1) Where is radiating surface? 2) What are the differences in extremes at the radiating surface? 3) What about differences in depth of heat pulse into the soil?
Slope & radiation Perpendicular radiation most energy per unit surface area
Angle of Direct Shortwave Radiation at Solar Noon Importance of Aspect (47) 90 (23.5+23.5) = 43 23.5 23.5 90 23.5 = 66.5 47 23.5 66.5 (43) 90 (66.5-23.5) = 47 (66.5) 90 (90-23.5) = 23.5
Calculate the angles of the sun with a horizontal surface at solar noon at each of the indicated latitudes on the dates of the equinoxes (12 hr light & 12 hrs dark) Arctic 66.5 Ames - 42 Cancer 23.5 Equator 90 Capricorn 23.5 Antarctic 66.5 Solar Interception at the Equinoxes
Calculate the angles in the Northern Hemisphere at the Solar Equinoxes Arctic 66.5 90 90 = 0 90 66.5 = 23.5 Ames - 42 90 42 = 48 Cancer 23.5 90 23.5 = 66.5 Equator Capricorn 23.5 Antarctic 66.5 90 90 23.5 = 66.5 90 66.5 = 23.5 90 90 = 0 Solar Interception at the Equinoxes
Group Activity What south-facing slope in Ames gets perpendicular radiation at the equinoxes? South-facing Solar altitude North-facing 42 90 180 48 What north-facing slope gets no direct shortwave radiation?
Cooling Dry Heating
Tropical/ Subtropical Arid Tropical/Subtropical Arid Tropical Wet-Dry 30 N Tropical Wet Tropical Wet Equator Tropical Wet Tropical Wet-Dry 30 S Tropical/Subtropical Arid Tropical/Subtropical Arid
Air Mass(Moisture) Movement Powered by Solar Radiation & Topography Give Rise to Varying Biomes in the United States Coastal Conifer Forest Intermoutain Grassland Central Valley Intermountain Region Great Basin Mid Grass Prairie Short Grass Prairie Tall Grass Prairie Eastern Deciduous Forest Southern Conifers
LWin H LWout RSW DSW Energy Balance for a Person Radiation Balance DifSW M S LE Direct shortwave (DSW) Diffuse shortwave (DifSW) Reflected shortwave (RSW) Atmospheric longwave in (LWin) Surface longwave out (LWout) Heat Balance Sensible heat into surface (S) Sensible heat from surface (H) Latent heat (LE) Metabolic heat (M) What is Chris Energy Balance
Radiation Balance Direct SW + Diffuse SW + Atmp LW (Reflected SW + Outgoing LW) = + Rn Where: SW = Shortwave radiation LW = Longwave Rn = net radiation What are the general differences in the radiation balance between day and night? What are the differences between cloudy and clear days?
Radiation Balance Daytime Direct Shortwave Radiation Diffuse Shortwave Radiation Reflected Shortwave Atmospheric Longwave Outgoing Longwave Net Radiation Input (positive) Output (negative) Radiating Surface Direct SW + Diffuse SW + Atmp LW (Reflected SW + Outgoing LW) = + Rn
Radiation Balance Night Direct Shortwave Radiation Diffuse Shortwave Radiation Reflected Shortwave Atmospheric Longwave Outgoing Longwave Net Radiation Input (positive) Output (negative) Radiating Surface Direct SW + Diffuse SW + Atmp LW (Reflected SW + Outgoing LW) = + Rn Atmp LW Outgoing LW = -Rn
Heat Balance + Rn = + H + S + LE + M Where: H = Sensible Heat lost from the radiating surface to the atmosphere (conduction & convection) S = Sensible heat into solids (plants, soil, water) LE = Latent heat of changes of state of water M = Metabolic energy of organism.
Heat Balance Day Net Radiation Energy Absorbed By Surface H Sensible Heating of Air LE Heat of Vaporization Fusion Input (positive) Output (negative) S Absorbed Heat into Soil/Medium M = Plant/Animal Metabolism Radiating Surface + Rn = -H -S -LE +M
Heat Balance Night Net Radiation Net Radiation Energy Absorbed Lost by By Surface Surface H Sensible H Sensible Heating of Heats of Air Surface LE Air Heat Cools of Vaporization Dew Deposited Fusion Input (positive) Output (negative) S Absorbed Soil Heat Returns Heat intoto Soil/Medium Surface + Rn -Rn= = -H + -S H + -LE S + +M LE Summer = +Rn Winter = - Rn Radiating Surface
M = Metabolic energy of organism. Energy Balance Consists of Radiation and Heat Balance Direct SW + Diffuse SW + Atmp LW (Reflected SW + Outgoing LW) = + Rn = + H + S + LE + M Where: SW = Shortwave radiation LW = Longwave Rn = net radiation H = Sensible Heat lost from the radiating surface to the atmosphere (conduction & convection) S = Sensible heat inot solids (plants, soil, water) LE = Latent heat of changes of state of water
Energy Balance - Daytime Radiation Balance Heat Balance Direct Shortwave Radiation Diffuse Shortwave Radiation Reflected Shortwave Atmospheric Longwave Outgoing Longwave Net Radiation LE Heat of H Vaporization Sensible Fusion Heating of Air Input (positive) Output (negative) S Absorbed Heat into Soil/Medium
Diagram the energy balance for forest & clearcut. Assume sunny summer day. Radiation Balance Direct shortwave (DSW) Diffuse shortwave (DifSW) Reflected shortwave (RSW) Atmospheric longwave in (LWin) Surface longwave out (LWout) Net Radiation (Rn) Heat Balance Sensible heat into surface (S) DSW LWin DifSW LWout RSW Rn LE H S Sensible heat from surface (H) Latent heat (LE) DSW RSW LWin LWout Rn H DifSW LE Conifer Forest Clearcut S
Please Develop the Energy Balance for the Grassland in the Valley and the Forest in the foreground DSW LWin DifSWRSWLWout Rn LE H S DSW LWin DifSWRSW LWoutRn LE H S
DSW LWin DifSW LWout RSW Rn LE H S Develop an Energy Balance for each site showing relative differences by size of arrows. DSW LWin DifSWRSW LWout Rn LE H S
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