Lec 12 - Introduction to Thermal Infrared

Question 1

Also known as longwave infrared (LWIR)

Answer 1

Thermal Infrared

Question 2

It is the sensing of emissive energy or “temperature” energy

Answer 2

Thermal Infrared

Question 3

Remote Sensing Measures (4)

Answer 3

(1) Land and Ocean Surface Temperature
(2) Atmospheric
(3) Radiation Balance
(4) Emissivity

Question 4

It is the parameter indicating the energy and water exchange between the surface and the atmosphere.

Answer 4

Land and Ocean Surface Temperature

Question 5

It measures temperature and amount of water vapor at different levels of the atmosphere

Answer 5

Temperature and humidity

Question 6

Other gasses present in small amounts within the atmosphere.

Answer 6

Trace Gas Concentration

Question 7

The balance between the radiant energy received by the Earth from the Sun and that returned by Earth to space

Answer 7

Radiation Balance

Question 8

The ratio of the energy radiated from a material’s surface to that radiated from a perfect emitter (blackbody)

Answer 8

Emissivity

Question 9

The measure of the motion of atoms and molecules in a substance

Answer 9

Temperature

Question 10

Energy of particles of matter in random motion

Answer 10

Kinetic Heat

Question 11

It can be measured using a thermometer

Answer 11

True Kinetic Temperature (Tkin)

Question 12

The emitted EM radiation caused by the collision of particles with kinetic heat

Answer 12

Radiant Flux (Watts)

Question 13

The amount of radiant flux emitted from an object

Answer 13

Radiant Temperature (Trad)

Question 14

Relationship between Tkin and Trad

Answer 14

There is usually a high positive correlation between the true kinetic temperature of an object (Tkin) and the amount of radiant flux radiated from the object (Trad)

Question 15

The most obvious source of EM radiation for remote sensing

Answer 15

Sun

Question 16

The ratio of radiance spectrum of a non-perfect emitter over that of a perfect emitter (blackbody) at the same temperature.

Answer 16

Emissivity spectrum

Question 17

The perfect absorber and emitter

Answer 17

Blackbody

Question 18

The law states that, “The total energy emitted/radiated per unit surface area of a blackbody across all wavelengths per unit time is directly proportional to the fourth power of the black body’s thermodynamic temperature.

Answer 18

Stefan-Boltzmann Law

Question 19

This law states that black body radiation has different peaks of temperature at wavelengths that are inversely proportional to temperatures.

Answer 19

Wien’s Displacement Law

Question 20

This means reflectivity and emissivity has an inverse relationship; “good absorbers are good emitters” and “good reflectors are poor emitters”

Answer 20

Kirchoff’s Radiation Law

Question 21

The most commonly used method for land surface temperature (LST) retrieval from satellite data (Wang et. al, 2019)

Answer 21

Split-window algorithm

Question 22

The measure of the increase in thermal energy content (Q) per degree of temperature rise

Answer 22

Thermal/heat capacity (C)

Question 23

The rate at which heat will pass through a material

Answer 23

Thermal conductivity (K)

Question 24

The rate at which temperature can change within a body (energy loss / gain characteristics)

Answer 24

Thermal diffusivity (k)

Question 25

It is a measure of a substance’s ability to transfer heat in and out of that portion that received solar heating during the day and cools at night (cm^2/s)

Answer 25

Thermal diffusivity (k)

Question 26

The thermal response, delay in reaching ambient temperature following exposure to energy

Answer 26

Thermal inertia (P)

Question 27

The measure of the heat transfer rate across a boundary between two materials

Answer 27

Thermal inertia (P)

Question 28

Any pattern that recurs every 24 hours as a result of one full rotation of the planet Earth around its axis.

Answer 28

Diurnal cycle (or diel cycle)

Question 29

Thermal Properties of Water

Answer 29

(1) Cooler in the day and warmer in the night relative to other materials in the scene
(2) High thermal inertia, relative to typical land surfaces, as controlled largely by water’s high specific heat.

Question 30

A device designed to measure and detect thermal (heat) energy.

Answer 30

Thermal energy detector

Question 31

The basic principle is the conversion of heat into a measurable signal.

Answer 31

Thermal energy detector

Question 32

This produces a voltage when heated

Answer 32

Thermocouple

Question 33

It undergoes a change in electrical resistance when heated

Answer 33

Bolometer

Question 34

It is much more complex and expensive and is not used on the best-selling thermal camera models for various applications

Answer 34

Quantum detector

Question 35

It is sensitive to infrared radiation, which is a form of thermal energy.

Answer 35

Infrared (IR) Detectors

Question 36

It is temperature-sensitive resistors whose resistance changes significantly with temperature

Answer 36

Thermistors

Question 37

Common Satellite Sensors in Thermal IR

Answer 37

(1) Landsat 8
(2) NOAA AVHRR Band 4
(3) GOES, GMS, MOS 1, SeaWiFs, Nimbus CZCS (1 thermal), SeaSat, HCMM
(4) Ceres

Question 38

Thermal Infrared (TIR) Applications

Answer 38

(1) provide accurate distributions of surface spectral emittance and temperature
(2) Heat and moisture fluxes (exchanges)
(3) Climatological processes
(4) Evapo-transpiration
(5) Soil moisture variation
(6) Hydrology, oceanography and ocean currents
(7) Biomass distribution
(8) Vegetation monitoring
(9) Lithology & geology
(10) Urban land use
(11) Natural disaster monitoring
(12) Thermal pollution