Priya Patel
Gather.town id
FMM12
Poster Title
Water Vapour in the Martian Atmosphere
Institution
Mullard Space Science Laboratory, University College London
Abstract (short summary)
The ExoMars Rover, launching in 2022, is designed to search for signs of past life through surface, sub-surface and atmospheric measurements using a wide array of instruments. One of them is the multispectral stereo imager, PanCam, containing a pair of Wide Angle Cameras (WACs), each with an 11-position filter wheel, and a High Resolution Camera (HRC). Two solar filters, SO1 and SO2, centered at 925nm and 935nm can be utilised to measure water vapour content in the atmosphere by measuring the 936 nm absorption feature. Through direct imaging of the rising and setting Sun as well as imaging the scattered light at the horizon, vertical distribution of water vapour can be retrieved in the lower Martian atmosphere. Using radiative transfer techniques and a sophisticated retrieval tool, NEMESIS (Non-linear optimal Estimator for MultivariatE Spectral analysIS), a vertical height profile can be computed. Currently, we are investigating the accuracy of these measurements using a PanCam instrument model and the Planetary Spectrum Generator tool. We are also investigating if similar measurements of water vapour in the lower atmosphere can be carried out using the MastCam-Z instrument onboard the Perseverance Rover at Jezero Crater.
Plain text (extended) Summary
The poster starts with an introduction to the project. Mars today is cold and dry, however, lots of evidence suggests that Mars, especially the Northern hemisphere, was once partly covered in flowing liquid water. Hence, studying the water cycle on Mars is important due to its importance in understanding the history of the Martian atmosphere that once allowed for liquid water to flow and the potential for life on the red planet. Much of the water found on Mars today is in the regolith, with some in the atmosphere and as water ice on the surface and sub-surface.
Following the introduction section, the poster goes into the method section describing the method used for gaining the results for this project. Using data from the ExoMars rover and Perseverance Rover, I will be studying the water vapour in the atmosphere by imaging the solar disk during sunset to allow for a larger path length and observe a larger part of the atmosphere. Figure 1 shows a schematic of the rover observing the solar disk during sunset. The Sun is seen just above the horizon.
The next section is the about the ExoMars rover, particularly the PanCam instrument, the stereo camera on board the rover. My project is to use the Panoramic Camera instrument, PanCam, built at the Mullard Space Science Laboratory, to study water vapour at Oxia Planum, the chosen landing site. I will be working on 2 ultra-narrow band solar filters, L10 and L11, centred at 925+/-5nm and 935 +/-5nm to detect water vapour. Water vapour has a distinct absorption band at 936nm hence with these two filters, we can image at the band and in the continuum as shown in figure 2. Figure 2 shows how the Solar Filters on the PanCam instrument fit on the Water Vapour Spectrum generated through Planetary Spectrum Generator. The Orange is the generator spectrum of water vapour in the Martian Atmosphere, the green is the 935nm filter line and the white is the 925nm filter line. The filters cover the absorption band and the continuum.
The following section contains the results and discussion. The solar filter transmissions were plotted for the L10 filter centred at 925nm as shown in the L11 filter centred at 935nm, shown in figure 3. Figure 3 contains graphs showing the transmission spectra for the L10 filter centred at 925nm, a red peak is seen at 925nm on the left and the L11 filter centred at 935nm, a blue peak is seen at 935nm on the right. The x-axis contains wavelengths between 900nm –1000nm and the y-axis shows the transmission spectra. To gain a deeper understanding of the accuracy of the data we will receive from PanCam instrument, I multiplied the water vapour spectra generated from the Planetary Spectrum Generator with the filter transmission spectra. A strong signal is seen in the 935nm filter, hence the difference in signal in the two filters can be used to measure water vapour content in the atmosphere. Figure 4 contains graphs showing the expected transmission spectra containing water vapour signal for the L11 filter centred at 935nm in blue on the right and the transmission spectra in the 925nm solar filter on the left in red. A big blue peak at 935nm is seen however no peak seen at the 925nm filter. The next section contains how the Perseverance rover can be used in a similar manner to measure water vapour using the MastCam-Z instrument. The last section contains a conclusion, this project is aimed at using data from ExoMars Mars2020 rover to detect water vapour in the atmosphere.
Following the introduction section, the poster goes into the method section describing the method used for gaining the results for this project. Using data from the ExoMars rover and Perseverance Rover, I will be studying the water vapour in the atmosphere by imaging the solar disk during sunset to allow for a larger path length and observe a larger part of the atmosphere. Figure 1 shows a schematic of the rover observing the solar disk during sunset. The Sun is seen just above the horizon.
The next section is the about the ExoMars rover, particularly the PanCam instrument, the stereo camera on board the rover. My project is to use the Panoramic Camera instrument, PanCam, built at the Mullard Space Science Laboratory, to study water vapour at Oxia Planum, the chosen landing site. I will be working on 2 ultra-narrow band solar filters, L10 and L11, centred at 925+/-5nm and 935 +/-5nm to detect water vapour. Water vapour has a distinct absorption band at 936nm hence with these two filters, we can image at the band and in the continuum as shown in figure 2. Figure 2 shows how the Solar Filters on the PanCam instrument fit on the Water Vapour Spectrum generated through Planetary Spectrum Generator. The Orange is the generator spectrum of water vapour in the Martian Atmosphere, the green is the 935nm filter line and the white is the 925nm filter line. The filters cover the absorption band and the continuum.
The following section contains the results and discussion. The solar filter transmissions were plotted for the L10 filter centred at 925nm as shown in the L11 filter centred at 935nm, shown in figure 3. Figure 3 contains graphs showing the transmission spectra for the L10 filter centred at 925nm, a red peak is seen at 925nm on the left and the L11 filter centred at 935nm, a blue peak is seen at 935nm on the right. The x-axis contains wavelengths between 900nm –1000nm and the y-axis shows the transmission spectra. To gain a deeper understanding of the accuracy of the data we will receive from PanCam instrument, I multiplied the water vapour spectra generated from the Planetary Spectrum Generator with the filter transmission spectra. A strong signal is seen in the 935nm filter, hence the difference in signal in the two filters can be used to measure water vapour content in the atmosphere. Figure 4 contains graphs showing the expected transmission spectra containing water vapour signal for the L11 filter centred at 935nm in blue on the right and the transmission spectra in the 925nm solar filter on the left in red. A big blue peak at 935nm is seen however no peak seen at the 925nm filter. The next section contains how the Perseverance rover can be used in a similar manner to measure water vapour using the MastCam-Z instrument. The last section contains a conclusion, this project is aimed at using data from ExoMars Mars2020 rover to detect water vapour in the atmosphere.
URL
priya.k.patel.16@ucl.ac.uk
Poster file