**4. Results and discussion**

### **4.1 Analysis of spectral signatures**

After comparing the spectral signatures of each of the 49 control points (**Table 1**) established in the study area, with the spectral signatures encoded (with range of wavelengths in nm) of the Earth (**Figures 3** and **4**), coincidences have been found in three of them (**Figure 5**), and more specifically with those corresponding to acid water 2, turbid water and frozen water (type 2), although only in 39 control points (**Table 3**).

On the other hand, and as a consequence of the existence of perchlorate salt (it enables the existence of acid water, in addition to facilitating the water evaporation at temperatures below 0°C) on Mars surface [15], a new algorithm, called Moisture Soil Index on Mars (MSIM), has been obtained, with which it is possible to obtain the humidity percentage in Martian soil. The expression of the MSIM is shown in Eq. (4):

$$\text{MSIM} \left( \forall \text{0} \right) = \text{10} \cdot \left[ \mathbf{1} - \left( \frac{\text{Blue band}}{\text{Red band}} \right)^{1.5} \right] \left( r = \text{0}, \text{71}; R^2 = \text{0}, \text{735} \right) \tag{4}$$

After comparing the MSIM with the WEH moisture index (it corresponds to the amount of hydrogen molecules in the water) established by [16] (**Figure 6**) it is observed that, although there is no relationship between both indices, it is true that a high WEH corresponds to high MSIM and vice versa.

In order to facilitate the use of this new index, an estimate of it can be obtained from the planetocentric coordinates of Mars, as shown in Eq. (5).

control points were established, in the form of a rectangular mesh, in the study area,

As a consequence of not having initial topographic values of the soil of Mars, nor of how they have varied over time, the total transported soil is calculated using the

although taking the area covered by Opportunity as a reference.

*Spectral signatures of two types of frozen water in the visible spectrum.*

**Water type 1** Mean spectral signature of water on Earth **Freshwater** Mean spectral signature of freshwater on Earth **Saltwater** Mean spectral signature of saltwater on Earth

*Solar System Planets and Exoplanets*

**Frozen water (type 1)** Mean spectral signature of water ice on Earth

*Different types of both water and ice, existing in the Earth, taken as reference.*

**Table 2.**

**Figure 3.**

**Figure 4.**

**82**

*Signature of water on Earth).*

**Acid water 1** Mean spectral signature of the acidic water belonging to the South Minas de

**Acid water 2** Mean spectral signature of the acidic water belonging to the North Minas de

**Turbid water** Mean spectral signature of turbid water existing in the Guadalquivir River (South of the Iberian Peninsula, Spain)

**Frozen water (type 2)** Mean spectral signature of the Sierra Nevada water ice (Granada, Spain)

*Spectral signatures of different types of water in the visible spectrum (MSS water on Earth is the Mean Spectral*

Riotinto reservoir (Huelva, Spain)

Riotinto reservoir (Huelva, Spain)

#### **Figure 5.**

*Spectral signatures found on Mars.*


**4.2 Analysis of moisture sources from Opportunity images**

*Comparison between WEH [16] and MSIM obtained for Mars in the study area.*

*Sedimentation and Proposed Algorithms to Detect the Possible Existence of Vegetation…*

*DOI: http://dx.doi.org/10.5772/intechopen.97628*

of rocks in the presence of acidic water.

observed around the drill area [21].

ephemeral (and shallow) lakes.

alteration due to the presence of water [27].

others.

**Figure 6.**

gravity force.

**85**

As is well known, according to [17], soil moisture plays a fundamental role both in the hydrological cycle and in land-atmosphere interactions. However, there are several studies in which the importance of the soil has been analyzed in various scientific areas, such as in climate simulations and meteorological prediction [18], in precipitation and runoff models [19] or in evapotranspiration [20] among

In this sense, and with regard to Eagle Crater, [21] specified that the outcrop, shown in the upper part of **Figure 7**, was wet by salt water, in addition to containing high concentrations of hematite and jarosite, minerals that form from the alteration

Regarding the Endurance crater, Opportunity made a total of seven holes using the rock abrasion tool. Likewise, the rover made combined mosaic images like the one shown in **Figure 8** on the left. Evidence of fine-grained red hematite was

It is convenient to emphasize that the dark green area, selected with the red arrow in **Figure 8** right, contains iron oxide compounds, which, on the surface of

In another vein, according to [26], the studied area by Opportunity have sandstones rich in sulfates, which indicates the existence of past erosion by the action of both the wind and by a slow water flow as a result of the possible formation of

In **Figure 9** right it can be seen that the dark green coloration, which indicates the presence of moisture [13], is found in the predominant stratum on the right. This stratum is formed by a lumpy rock called Wopmay located on the inner of Endurance slopes. It is believed that this type of rock is the consequence of an

Mars, have a color similar to that of hematite on Earth (gray).

At this point, it is very important to mention that, according to [23], depending on the texture and structure of the soils, these can contain a certain amount of moisture that is normally generated as a result of a rainfall event [24], that saturates the soil causing a portion to drain towards the interior due to the

**Table 3.**

*Planetocentric coordinates of Mars with coincidences in spectral signature with Earth (C.P. = Control Point).*

$$\text{MSIM}\left(\text{\textquotedbl{}}\text{\textquotedbl{}} = -\text{0}, \text{32} + \text{0}, \text{014} \cdot \text{L} + \text{0}, \text{063} \cdot \text{L} \text{at} - \text{0}, \text{033} \cdot \text{L} \text{on}\left(r = \text{0}, \text{71}; \mathbb{R}^2 = \text{0}, \text{47}\right)\right) \tag{5}$$

Knowing that:

L = Luminance of each pixel = Red + Green + (Blue/3). It is a dimensionless index.

Lat = Latitude in decimal degrees.

Lon = Longitude in decimal degrees.

*Sedimentation and Proposed Algorithms to Detect the Possible Existence of Vegetation… DOI: http://dx.doi.org/10.5772/intechopen.97628*

**Figure 6.** *Comparison between WEH [16] and MSIM obtained for Mars in the study area.*

#### **4.2 Analysis of moisture sources from Opportunity images**

As is well known, according to [17], soil moisture plays a fundamental role both in the hydrological cycle and in land-atmosphere interactions. However, there are several studies in which the importance of the soil has been analyzed in various scientific areas, such as in climate simulations and meteorological prediction [18], in precipitation and runoff models [19] or in evapotranspiration [20] among others.

In this sense, and with regard to Eagle Crater, [21] specified that the outcrop, shown in the upper part of **Figure 7**, was wet by salt water, in addition to containing high concentrations of hematite and jarosite, minerals that form from the alteration of rocks in the presence of acidic water.

At this point, it is very important to mention that, according to [23], depending on the texture and structure of the soils, these can contain a certain amount of moisture that is normally generated as a result of a rainfall event [24], that saturates the soil causing a portion to drain towards the interior due to the gravity force.

Regarding the Endurance crater, Opportunity made a total of seven holes using the rock abrasion tool. Likewise, the rover made combined mosaic images like the one shown in **Figure 8** on the left. Evidence of fine-grained red hematite was observed around the drill area [21].

It is convenient to emphasize that the dark green area, selected with the red arrow in **Figure 8** right, contains iron oxide compounds, which, on the surface of Mars, have a color similar to that of hematite on Earth (gray).

In another vein, according to [26], the studied area by Opportunity have sandstones rich in sulfates, which indicates the existence of past erosion by the action of both the wind and by a slow water flow as a result of the possible formation of ephemeral (and shallow) lakes.

In **Figure 9** right it can be seen that the dark green coloration, which indicates the presence of moisture [13], is found in the predominant stratum on the right. This stratum is formed by a lumpy rock called Wopmay located on the inner of Endurance slopes. It is believed that this type of rock is the consequence of an alteration due to the presence of water [27].

*MSIM* ð Þ¼� % 0, 32 <sup>þ</sup> 0, 014 � *<sup>L</sup>* <sup>þ</sup> 0, 063 � *Lat* � 0, 033 � *Lon r* <sup>¼</sup> 0, 71; *<sup>R</sup>*<sup>2</sup> <sup>¼</sup> 0, 47

*Planetocentric coordinates of Mars with coincidences in spectral signature with Earth (C.P. = Control Point).*

**Acid water 2 Turbid water Frozen water (type 2)**

**C.P. Lat Long C.P. Lat Long C.P. Lat Long C.P. Lat Long 1** 10° �15° **17** 3° �5° **11** 7° 0° **18** 3° 0°

 10° �10° **21** 3° 15° **19** 3° 5° 10° �5° **23** 0° �10° **20** 3° 10° 10° 0° **24** 0° �5° **22** 0° �15° 10° 5° **27** 0° 10° **26** 0° 5° 10° 10° **28** 0° 15° **31** �3° �5° 10° 15° **29** �3° �15° **36** �7° �15° 7° �15° **30** �3° �10° **41** �7° 10° 7° �10° **34** �3° 10° **43** �10° �15° 7° �5° **35** �3° 15° **44** �10° �10° 7° 10° **37** �7° �10° **47** �10° 5°

L = Luminance of each pixel = Red + Green + (Blue/3). It is a dimensionless

Knowing that:

**16** 3° �10°

Lat = Latitude in decimal degrees. Lon = Longitude in decimal degrees.

**14** 7° 15° **45** �10° �5° **15** 3° �15° **49** �10 15°

index.

**84**

**Table 3.**

**Figure 5.**

*Spectral signatures found on Mars.*

*Solar System Planets and Exoplanets*

(5)

#### **Figure 7.**

*Image taken by Opportunity (Sol 4) at Eagle Crater [22]. The lower image shows the wet areas (red arrows) after subjecting the upper image to the process patented by [13].*

### **4.3 Model to obtain water flow velocity based on pebbles diameter**

To obtain this model, both in the Chaqui River (Bucay, Ecuador) and in a stream located in Bonita Creek (California, USA), the water velocity was calculated at a series of points established in field (15 in Ecuador and 10 in the USA), to later measure the average pebbles diameter at those same points. Subsequently, with the use of genetically modified algorithms, although taking into account the gravity of Mars (3,7 m/s2 ), the water flow velocity that should exist on Mars was calculated to have pebbles of the same diameter as those measured in the specified sampling points. For this process, the DTM obtained by MOLA was also used. The result was that the water flow velocity on Mars having to be in a relationship as shown in Eq. (6):

$$\mathbf{V}\_{on\ Mars} = \frac{\mathbf{e}^{D\_{on\ Earth}}}{\mathbf{3}} \begin{pmatrix} r = \mathbf{0}, \mathfrak{P}\mathbf{1}; R^2 = \mathbf{0}, \mathfrak{P}\mathbf{9} \end{pmatrix} \tag{6}$$

*Von Mars* <sup>¼</sup> 0, 4961 � *Dpebbles on Mars* <sup>þ</sup> 0, 3025 *<sup>r</sup>* <sup>¼</sup> 0, 98; *<sup>R</sup>*<sup>2</sup> <sup>¼</sup> 0, 99 (7)

Later, with the use of the free software ImageJ (**Figure 11**), the pebbles diameter

As can be seen in **Figure 10**, as well as in Eq. (7), the water velocities obtained on

Throughout its history, and according to [24], the surface of Mars has had a very

Mars are in the same velocities range as those obtained in a salt-marsh, for this reason the model shown in Eq. (3) and proposed by [11] has been used. The transport of sediments in study area has been calculated through an evaluation to pixel level (**Figure 12**) using the DTM obtained by MOLA and the patented procedure by [13]. In this figure, sediment transport is simulated based on climatic conditions [28] on Mars and a surface shape factor dependent of algorithm

active hydrological cycle, which has given rise to a network of valleys formed, mainly, by the surface flow erosion, leaving, as secondary factor, erosion due to groundwater seepage. It is precisely this fact that makes it possible for the depth

profile at the control points 12, 15 and 77 to reach the values �1437,47 m,

Authors want to record that the model shown in Eq. (7) has been used by two studies, pending publication, in the areas of the Spirit and Curiosity rovers respectively, obtaining results that are fully consistent with the reality of Mars.

*Image taken by Opportunity (Sol 173) at Endurance Crater [25]. The right image shows the wet areas (red*

*Sedimentation and Proposed Algorithms to Detect the Possible Existence of Vegetation…*

*DOI: http://dx.doi.org/10.5772/intechopen.97628*

in the study area was measured. In **Figure 11** is shown a measure that no corresponding to a pebbles only to show, clearly, the procedure used. Pebbles diameters measured in study area fit perfectly (see **Figure 10**) with Eq. (7).

**4.4 Prediction of erosion in Meridiani Planum**

*arrow) after subjecting the upper image to the process patented by [13].*

�1676,72 m and � 2873,03 m respectively.

used by [13].

**87**

**Figure 8.**

Once the water velocity on Mars was obtained, it was represented against the diameter, obtaining the model presented in **Figure 10**, and from which it is possible to calculate the water velocity in any area of Mars as long as there is evidence that it was covered by water. In Eq. (7) the model presented in **Figure 10** is appropriately specified.

*Sedimentation and Proposed Algorithms to Detect the Possible Existence of Vegetation… DOI: http://dx.doi.org/10.5772/intechopen.97628*

#### **Figure 8.**

**4.3 Model to obtain water flow velocity based on pebbles diameter**

*after subjecting the upper image to the process patented by [13].*

*Solar System Planets and Exoplanets*

flow velocity on Mars having to be in a relationship as shown in Eq. (6):

*Von Mars* <sup>¼</sup> *<sup>e</sup>Don Earth*

specified.

**86**

**Figure 7.**

To obtain this model, both in the Chaqui River (Bucay, Ecuador) and in a stream located in Bonita Creek (California, USA), the water velocity was calculated at a series of points established in field (15 in Ecuador and 10 in the USA), to later measure the average pebbles diameter at those same points. Subsequently, with the use of genetically modified algorithms, although taking into account the gravity of Mars (3,7 m/s2

*Image taken by Opportunity (Sol 4) at Eagle Crater [22]. The lower image shows the wet areas (red arrows)*

the water flow velocity that should exist on Mars was calculated to have pebbles of the same diameter as those measured in the specified sampling points. For this process, the DTM obtained by MOLA was also used. The result was that the water

Once the water velocity on Mars was obtained, it was represented against the diameter, obtaining the model presented in **Figure 10**, and from which it is possible to calculate the water velocity in any area of Mars as long as there is evidence that it was covered by water. In Eq. (7) the model presented in **Figure 10** is appropriately

<sup>3</sup> *<sup>r</sup>* <sup>¼</sup> 0, 91; *<sup>R</sup>*<sup>2</sup> <sup>¼</sup> 0, 99 (6)

),

*Image taken by Opportunity (Sol 173) at Endurance Crater [25]. The right image shows the wet areas (red arrow) after subjecting the upper image to the process patented by [13].*

$$N\_{on\ Mars} = 0,4961 \cdot D\_{\text{pebble}\ on\ Mars} + 0,3025 \left(r = 0,98; R^2 = 0,99\right) \tag{7}$$

Authors want to record that the model shown in Eq. (7) has been used by two studies, pending publication, in the areas of the Spirit and Curiosity rovers respectively, obtaining results that are fully consistent with the reality of Mars.

Later, with the use of the free software ImageJ (**Figure 11**), the pebbles diameter in the study area was measured. In **Figure 11** is shown a measure that no corresponding to a pebbles only to show, clearly, the procedure used. Pebbles diameters measured in study area fit perfectly (see **Figure 10**) with Eq. (7).

#### **4.4 Prediction of erosion in Meridiani Planum**

As can be seen in **Figure 10**, as well as in Eq. (7), the water velocities obtained on Mars are in the same velocities range as those obtained in a salt-marsh, for this reason the model shown in Eq. (3) and proposed by [11] has been used.

The transport of sediments in study area has been calculated through an evaluation to pixel level (**Figure 12**) using the DTM obtained by MOLA and the patented procedure by [13]. In this figure, sediment transport is simulated based on climatic conditions [28] on Mars and a surface shape factor dependent of algorithm used by [13].

Throughout its history, and according to [24], the surface of Mars has had a very active hydrological cycle, which has given rise to a network of valleys formed, mainly, by the surface flow erosion, leaving, as secondary factor, erosion due to groundwater seepage. It is precisely this fact that makes it possible for the depth profile at the control points 12, 15 and 77 to reach the values �1437,47 m, �1676,72 m and � 2873,03 m respectively.

#### **Figure 9.**

*Image taken by Opportunity (Sol 248) at Endurance Crater [27]. The right image shows the wet areas (red arrows) after subjecting the upper image to the process patented by [13].*

**Figure 11.**

**Figure 12.**

**89**

*values = soil erosion).*

*Procedure used to measure diameter (length measurements are in pixels).*

*Sedimentation and Proposed Algorithms to Detect the Possible Existence of Vegetation…*

*DOI: http://dx.doi.org/10.5772/intechopen.97628*

*Variation of the depth in terms of sediment transport in study area (positive values = soil deposition; negative*

*Sedimentation and Proposed Algorithms to Detect the Possible Existence of Vegetation… DOI: http://dx.doi.org/10.5772/intechopen.97628*

**Figure 11.** *Procedure used to measure diameter (length measurements are in pixels).*

#### **Figure 12.**

*Variation of the depth in terms of sediment transport in study area (positive values = soil deposition; negative values = soil erosion).*

**Figure 10.**

**88**

**Figure 9.**

*Solar System Planets and Exoplanets*

*Relationship between the water velocity (m/s) and the pebbles diameter (m) on Mars surface.*

*Image taken by Opportunity (Sol 248) at Endurance Crater [27]. The right image shows the wet areas (red*

*arrows) after subjecting the upper image to the process patented by [13].*
