2.4 Lunar Landform and Topography
31
Length of baseline
Length of baseline
Angle of slope/(°)
(b)
Angle of slope/(°)
(a)
Cumulative percentage/%
Cumulative percentage/%
Fig. 2.7 The cumulative distribution of the slope of the smooth mare and rough mare. a Smooth
mare; b Rough mare
smaller (in Fig. 2.7, the cumulative area below the maximum slope is about 95%
of the total area). Take the smooth mare as an example, the maximum slope is about
10° when the baseline is 1 m, and the maximum slope is about 5° when the baseline
is 50 m.
Table 2.4 shows the cumulative percentage of the area that is occupied by the slope
over a certain angle, with the slope ranges from 0 to 15° and the baseline length is
10 m and 25 m.
It shows that the longer the baseline, the smaller the percentage of area that is
occupied by the slope over a certain angle by analysis of the data in Table 2.4. For
the smooth mare, the percentage of area that is occupied by the slope greater than 7°
is 0 when the baseline length is 10 m.
2. Distribution of Rocks on Lunar Surface
The cumulative distribution of rocks in different topography is shown in Fig. 2.8.
By applying fitting method to Fig. 2.8, the cumulative number of rocks with
diameter greater than D in a unit area (1 m
2 ) in smooth mare, rough mare and upland
can be estimated. The functions are shown below.
In the smooth mare, the cumulative number of rocks N b,s (m
−2 ) larger than a
certain diameter in a unit area (1 m
2 ) can be expressed as
N b,s (D) = 10
−3.3955
× D
−2.589
(2.1)
where D is the diameter of rock.
In the rough mare, the cumulative number of rocks N b,r (m
−2 ) larger than a certain
diameter in a unit area (1 m
2 ) can be expressed as
31
Length of baseline
Length of baseline
Angle of slope/(°)
(b)
Angle of slope/(°)
(a)
Cumulative percentage/%
Cumulative percentage/%
Fig. 2.7 The cumulative distribution of the slope of the smooth mare and rough mare. a Smooth
mare; b Rough mare
smaller (in Fig. 2.7, the cumulative area below the maximum slope is about 95%
of the total area). Take the smooth mare as an example, the maximum slope is about
10° when the baseline is 1 m, and the maximum slope is about 5° when the baseline
is 50 m.
Table 2.4 shows the cumulative percentage of the area that is occupied by the slope
over a certain angle, with the slope ranges from 0 to 15° and the baseline length is
10 m and 25 m.
It shows that the longer the baseline, the smaller the percentage of area that is
occupied by the slope over a certain angle by analysis of the data in Table 2.4. For
the smooth mare, the percentage of area that is occupied by the slope greater than 7°
is 0 when the baseline length is 10 m.
2. Distribution of Rocks on Lunar Surface
The cumulative distribution of rocks in different topography is shown in Fig. 2.8.
By applying fitting method to Fig. 2.8, the cumulative number of rocks with
diameter greater than D in a unit area (1 m
2 ) in smooth mare, rough mare and upland
can be estimated. The functions are shown below.
In the smooth mare, the cumulative number of rocks N b,s (m
−2 ) larger than a
certain diameter in a unit area (1 m
2 ) can be expressed as
N b,s (D) = 10
−3.3955
× D
−2.589
(2.1)
where D is the diameter of rock.
In the rough mare, the cumulative number of rocks N b,r (m
−2 ) larger than a certain
diameter in a unit area (1 m
2 ) can be expressed as