Discussion on

Discussion on

Prata et al. 1995: Thermal Remote Sensing of Land Surface Temperature

from Satellite: Current Status and Future Prospects.

Which range of wavelength of this paper discuss?

• Shortwave? Near Infrared? Thermal Infrared?

• What two channels of AVHRR used in LST retrieval?

two different wavebands, 10.5-11.5μm and 11.5-12.5 μm (channels 4 and 5 in AVHRR)

• Why this range? (p187)

The important effects of____________, ___________and___________________ are considered and the current practice for removing these effects is specified.

The important effects of the atmosphere, surface emissivity and instrument noise are considered and the current practice for removing these effects is specified.

What can LST be used for?

• Calculating SEB (what is 2-way)• In model (what is initialization)• Regional EP estimation• Frost detection• Monitor water-stress in crops• Thermal inertia studies

When LST retrieval started?

retrieval accuracy?

• What is LST retrieval accracy?• What is SST retrieval accracy?• What is the logic relation etwee SST

retrieval and LST retrieval?• Why LST retrieval is ____ than SST

retrieval?

• Discuss: “The land surface presented particular problems for temperature determination not evident over the sea”

• Surface Emissivity• Making a representative measurement of

LST• The validation of satellite LST (Definition and meaning of LST)

Section 2: Definition of Surface Temperature

• The ____ channels of AVHH measure the _______ over an area of approximately

_______ km2

What is its field of view?, what is its pixel size?

Section 2: Definition of Surface Temperature

• After correcting for _____ and _____, the surface temperature inferred is a _______

Representative of the area corresponding to the ____________ of instrument?

Section 2: Definition of Surface Temperature

• What is flux definition? • What is the assumption and basis for such a

definition?

• Why it says “when the surface is not a blackbody, the definition of the radiative surface temperature will depend on the ____, and on the ____”?

Section 2: Definition of Surface Temperature

• What is the definition based on planck function?

Section 2: Definition of Surface Temperature

• What is the thermodynamic measure of the surface temperature?

• What is numerical model used surface temperature?

Section 3 Simple and COmples Land Surface

MODIS Land Cover Classification(M. A. Friedl, A. H. Strahler et al. – Boston University)

0 Water

1 Evergreen Needleleaf Forest

2 Evergreen Broadleaf Forest3 Deciduous Needleleaf Forest

4 Deciduous Broadleaf Forest

5 Mixed Forests

6 Closed Shrublands7 Open Shrublands

8 Woody Savannas

9 Savannas

10 Grasslands

11 Permanent Wetlands

12 Croplands

13 Urban and Built-Up

14 Cropland/Natural Veg. Mosaic

15 Snow and Ice16 Barren or Sparsely Vegetated

17 Tundra

(Jin and Dickinson 2010, ERL)

Sec. 4What is Split-window Algorithm?

• The general form of the algorithm is

Eq. (5)

Sobrino et al. notes that in order to gain an LST accracy of ____, the spectral emissivity mst be known to an accuracy of _________

Sec. 4What is Split-window Algorithm?

Prate (1994a) was able to show that LST accuracies of _________ is possible.

Sobrino et al. notes that in order to gain an LST accracy of ____, the spectral emissivity mst be known to an accuracy of _________

Is this LST accuracy practical?

Section 4:aerosol effect

• The aerosol effect in the _____ is ____, and often ____, if compared with the effect in the visible and near infrared regions.