Remote sensing for resources development and environmental management: Remote sensing for resources development and environmental management

Damen, M. C. J.

Bibliographic data

Multivolume work

Persistent identifier:: 856342815

Title:: Remote sensing for resources development and environmental management

Sub title:: proceedings of the 7th international Symposium, Enschede, 25 - 29 August 1986

Year of publication:: 1986

Place of publication:: Rotterdam; Boston

Publisher of the original:: A. A. Balkema

Identifier (digital):: 856342815

Language:: English

Additional Notes:: Volume 1-3 erschienen von 1986-1988

Editor:: Damen, M. C. J.

Document type:: Multivolume work

Volume

Persistent identifier:: 856343064

Title:: Remote sensing for resources development and environmental management

Sub title:: proceedings of the 7th international Symposium, Enschede, 25 - 29 August 1986

Scope:: XV, 547 Seiten

Year of publication:: 1986

Place of publication:: Rotterdam; Boston

Publisher of the original:: A. A. Balkema

Identifier (digital):: 856343064

Illustration:: Illustrationen, Diagramme

Signature of the source:: ZS 312(26,7,1)

Language:: English

Usage licence:: Attribution 4.0 International (CC BY 4.0)

Editor:: Damen, M. C. J.

Publisher of the digital copy:: Technische Informationsbibliothek Hannover

Place of publication of the digital copy:: Hannover

Year of publication of the original:: 2016

Document type:: Volume

Collection:: Earth sciences

Chapter

Title:: 3 Spectral signatures of objects. Chairman: G. Guyot, Liaison: N. J. J. Bunnik

Document type:: Multivolume work

Structure type:: Chapter

Chapter

Title:: Theoretic reflection modelling of soil surface properties. B. P. J. van den Bergh & B. A. M. Bouman

Document type:: Multivolume work

Structure type:: Chapter

s of absorption icients of volume of each minerais, the d to be : eq. 4 on of the mi- on of minerai i minerai i he results of amples of pure .h the aid of .ion of three ive been calcu- icident radia- a function quartz, gypsum don ( - 1 p 2 ) licite . . 188 . .062 ). 969 ) . 905 ) .855 ). 8 2 1 ). 793 ). 77 1 ). 7 4 1 3.724 3.688 erals in a reflectance aid of equa- the minera- icle size of urfaces (van ve been air- alcite and n small cups >s and mean ) i1 s ample s. ¡ample B 'O !5 ). 2 .25-250 ilculated and >fotometer; and 2b. L, 100 _ "-'80 .. o <1> £40 ‘ 0) u 20 ■■ # ! measured X * : calculated _i i i 1 . i . i . i i L u i 1 I ' 1.0 1.4 1.8 2.2 wavelength tyumf Figure 2a. Calculated and measured reflectance of sample A. 1.0 1.4 1.8 2.2 wavelength (um) Figure 2b. Calculated and measured reflectance of sample B. In general, the same trend is observed for the measured reflectance and the calculated reflectance. The presence of gypsum in sample B is clearly recognised in the characteristic dips around 1.4 and 1.9 um in the measured reflectance curve. These dips, although less pronounced, are also observed in the calcula ted reflectance curve. Differences in reflec tance value are due to differences in cali bration of the two spectrometers; to differen ces in sample preparation (the depth of the Hunt and Salisbury samples was only 3.5 mm); and to differences in shape and surface structure between the minerals used by Hunt and Salisbury and those in the Tunesian soil samples. The influence of soil water The influence of soil water on reflection from soil surfaces is complex and involves many variables. Adding water to a sample of dry soil introduces an extra component of ab sorption which optical characteristics depend on its solute content and on the tension at which it is bound to the soil mass (pF). An attempt has been made here to include soil water as a single parameter in modelling at the intrinsic soil surface level. Again, re ference is made to Bowers and Hanks (B&H, 1965): "The effect of moisture content on re flection from a Newtonian Silt Loam". Plots of Ln(r) versus moisture content at different wavelengths showed a linear relation between Ln(r) and moisture content. It is assumed that the influence of soil water on mean pe netrated layer thickness can be neglected when compared to its effect on the coeffi cient of absorption. On this assumption, the following formula for the coefficient of ab sorption of the total soil mass is proposed : 2 k = k + 9 k (m ) eq.5 s w w in which : k = coefficient of absorption of the total soil mass k = coefficient of absorption of the dry soil mass k = coefficient of absorption of the soil water 9 = moisture content in percentage of volume Applying this equation to the measurements of Bowers and Hanks raised the problem of finding some input for the mean penetrated layer thickness d. Since no specifications concerning aggregate size of the Newtonian Silt Loam could be found, arbritary values for the mean aggregate diameter 0 have been chosen. In figure 3,calculated values for k , using equation 5 and 3 with 0 = 100, 500 and 1000 |im,are plotted against wavelength of incident radiation. Figure 3. Calculated values of k tion of wavelength, and k derived et al. , 1965 . W as a fune- from Allen The shape of these curves compares well with that of the water absorption curve of Allen et al. , 196-5. Considering the method used for obtaining some value for mean penetrated la yer thickness, no comparison between absolute values for k can be made. Also, the influen- ■i w ce of soil water composition and soil water tension on k has not been taken into ac count. CONCLUDING REMARKS The combination of equation 3, equation 4 and equation5 leads to the following formu la, describing reflectance from a moist mix ture of mineral matter in a specific parti cle size class : r = exp ( - ( Y*c . k . + 9 k ) (vf^Ln ( 0/X) ) ) eq.6 11 w w Modelling of intrinsic soil surface reflec tion has to include more variables such as shape and surface structure of the particles and aggregates, nature and content of organic

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