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OCN 5401. Chapter 3 Heat Transfer Instructor: Dr. George A. Maul gmaul@fit.edu / X 7453. Heat Flux (W·m -2 = J·s -1 ·m -2 ). Q s – radiation from the sun Q b – back radiation from Earth Q e – evaporative heat loss or gain Q h – sensible heat loss or gain
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OCN 5401 Chapter 3 Heat Transfer Instructor: Dr. George A. Maul gmaul@fit.edu / X 7453
Heat Flux(W·m-2 = J·s-1·m-2) • Qs – radiation from the sun • Qb – back radiation from Earth • Qe – evaporative heat loss or gain • Qh – sensible heat loss or gain • Qv – advective heat loss or gain Qt = Qs – Qb – Qe – Qh – Qv
Radiation Paths irradiance reflected V1 V2 scattered refracted absorbed Index of Refraction (η2/η1) = V1/V2 ηwater-air = 1.333 (at 20°C) transmitted Willebrord Snell
Solar Spectrum Max Planck
CSUN: What is the solar constant? where If TSUN = 5775K, QSUN = ?
Distribution of Water and Land Solar Heating Inflow = Outflow CSUN(1-A)πr2 = 4πr2σT4 If A=0.3 and CSUN=1367 W·m-2, what is T=?
Earth’s mean temperature balance requires an extra term QGHE: What is the greenhouse effect? TEarth: What is Earth’s temperature? A: Is Earth’s albedo fixed?
How would Earth’s temperature change if the albedo changed from 30% to 29%? minus If TEARTH(A=30%) = 288K, TEARTH(A=29%) = ?
Relative Humidity (RH) and Saturation Vapor Pressure (es) Example: RH = ? Tair = 30°; Tdew point = 10° es = 39 mb; eair = 12 mb
Evaporation from the Sea Surface Qe = ρwaterE·L E is in meters per second, and latent heat of evaporation L= 2495 x 103 J·kg-1
Satellite Imagery Infrared Image
Sea Surface Temperature (SST) – Skin Temperature and Bulk Temperature
OCN 5401 Chapter 3 Questions?