Good morning! My name is Amelia Franklin from the Direct Readout Laboratory at NASA Goddard Space Flight Center. Alright, so Prospects of Real-Time Radar for Environmental Remote Sensing.
There are obvious benefits to taking geophysical measurements via remote sensing. They have provided for much of our understanding of earth’s environment and systems. The measurements have also allowed for countless applications from weather forecasting, looking at sea winds or agricultural productivity from soil moisture measurements. Geophysical remote sensing also allows for mapping of these measurements, like climate maps
Now what is underexploited is biomass remote sensing, specifically via active radar. Biomass radar remote sensing is a relatively nascent field, therefore it has the potential to provide for many new discoveries in addition to its anticipated applications. Much like how current satellites have often surpassed their goals by providing applications and information that was not originally intended, biomass radar remote sensing has the same possibility. Also like geophysical remote sensing, biomass radar remote sensing would allow for measurements to be made anywhere on earth. Perhaps most importantly however, this would allow for DIRECT assessment of ecosystem and environmental health
Note that remote sensing may measure physical qualities of biomass, like a height/density measurement of a forest. Direct in this case means actually measuring the response of biomass to stimuli from radar pulse
Instead of using radar to directly measure biomass, current methods for monitoring biomass health (and by health I mean changes in whether vegetation is diseased, or dying etc. and the implications this may have on the surrounding environment and ecosystems) so our current methods include for the most part In-situ measurements which require human presence, which can be a limitation. Also these measurements are temporally perishable. In other words, it would be really nice to get the data quickly. We also use geophysical measurements to infer ecosystem health.
So these inference-based measurements take geophysical measurement data to make estimates about biomass interaction and health. Although these geophysical measurements are not a direct assessment of biological systems, they have and will continue to serve an important role in understanding living environments and change, so therefore they are undeniably complimentary to biomass radar remote sensing.
In terms of monitoring ecosystem health, there are goals that biomass radar remote sensing can attack directly. It would be useful to assess rehabilitation and reclamation progress in areas like old coal mines where humans are trying to restore what they have changed or damaged. Also, we could use data for monitoring ecosystem stability, such as how human contact and construction has impacted surrounding ecosystems. Plus, we can assess whether ecosystems are in danger of being damaged and plan human development accordingly Another application would be to monitor the overall health of vegetation across Earth which affects all living organisms on the planet
So remote sensing of biomass is in practice, but I’m advocating the use of active radar to stimulate a response from biomass. radar has its benefits over passive instruments. Unlike passive instruments, active radar is relatively resistant to obstructions like clouds, using low frequencies to penetrate these obstacles Also helpful and unique to active radar is the constant stimulating pulse. One that I believe can magnify responses specific to biomass. With this magnification, measurement accuracy would be strengthened and potentially cause a bimodal response, allowing for further measurements.
Oregon state university’s oceanography department uses an algorithm to detect fluorescence of chlorophyll to assess health of phytoplankton. The more fluorescence, the healthier the phytoplankton because they have more than enough light to go through photosynthesis. Light energy not used in photosynthesis is lost as heat and fluorescence. The algorithm to detect fluorescence is derived from MODIS, a passive satellite instrument. There was thought that the signal would not be strong enough to be detected by a passive satellite instrument but it has been successful. active radar could magnify the signal to make it more easily detectable.
The use of biomass radar remote sensing can be an alternative path to useful applications. PAUSE Here, the biomass application is assessing ecosystem health/stability. The difference in each path is how to get to that application. One way would be the geophysical measurements of the density and height of a forest. That measurement is then used for an application to monitor deforestation trends. Finally, with our knowledge of the effects of deforestation, we can make an inference as to how well forest ecosystems are doing. The other path would be to directly measure fluorescence from the radar on a satellite. An increase or decrease in fluorescence of an area would indicate healthy or unhealthy vegetation, thus allowing for the application of monitoring health of vegetation and thus the health of the surrounding ecosystem
The Decadal survey highlighted new earth monitoring satellites, whose data could provide for societal benefit. As an example of an upcoming mission with radar that is intended for geophysical measurements, The soil moisture active passive mission is designed to use both a passive and active component to achieve a desired sensitivity to soil moisture. Its applications will include agricultural mapping (looking at soil saturation of a region and predicting crop yield)
Now this illustration expresses the differences between collecting soil moisture data actively and passively for SMAP. The passive instrument waits for signal to reach its detector whereas the active radar send a pulse and stimulates a response. As a result, there is a possibility of getting a bimodal response or multiple signals to measure, supplying more data and possibly providing for more applications. The active radar data will include information on the surface roughness of the terrain and on quantity of vegetation. The passive instrument will pick up a purer measurement of just soil moisture mostly. The SMAP mission combines the two instruments for comprehensive measurements.
SMAP is also an example of how Direct Broadcast can be highly useful. So direct broadcast is directly transmitting satellite feed to the ground with little time constraints relative to satellites that do not have DB capabilities. having access to real-time or near-real-time environmental information is critical in decision support systems.
Here is a list of potential SMAP applications that could prove useful in real-time and a potential user for that application. PAUSE A local emergency government cant wait for a science product that they can use for an application to determine risk for landslides. If data about soil moisture is acquired quickly, emergency action can take place to relocate people in hilly areas where incoming rains could cause landslide or mudslides. Likewise, determining terrain trafficability is time-sensitive for the Army Future Combat System. The army has requirements for soil saturation in regions where they may deploy tanks. If the ground is too moist, tanks will have trouble navigating and will not be useful. The army can access data and plan tank routes based on where soil meets requirements. PAUSE
To sum up my presentation, I believe that putting emphasis on stimulating biomass with active radar to measure its response will enhance our current biomass remote sensing practices. Also, as I previously expressed through the potential applications for the SMAP mission, with any new biomass radar remote sensing application, it should be assessed whether the data and hence application would be useful in real-time. If so, DB should be considered a useful asset for these applications.
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