On May 6, 2018 as Kilauea continued to erupt, MISR passed overhead at approximately 11 a.m. local time, capturing this view of the island. While much of the island is covered by clouds, the eruption plume is visible streaming southwest over the ocean starting at the fissure on Hawaii’s eastern point. MISR uses it’s unique, nine-angle view to calculate plume height. This image is from one of MISR’s forward pointing cameras. The plume height is relatively low, meaning that gas and ash are staying near the ground, potentially causing health risks from poor air quality downwind.
Ash from Kilauea Eruption Viewed by NASA’s MISR on NASA JPL’s Photojournal
When volcanoes erupt, ASTER turns its attention to documenting the changes to the landscape as they happen. ASTER is uniquely capable of turning to see areas where volcanoes are erupting in very high resolution (between 15 in the thermal bands – 90 meter spatial resolution in the visible light spectral bands).
As Hawaii’s Kilauea continues to erupt, ASTER continues to monitor the eruption from space. This image from May 6, 2018 shows the sulfur dioxide being released from the volcano in yellow and yellow-green.
Satellite View of Kilauea Eruption from NASA JPL
Difference of mean tropospheric OMI NO2 columns from 2005–2006 to 2008–2009, and from 2011–2012 to 2014–2015. The unit is 1015 mole/cm2. (G and H) same as A–F, but for MOPITT surface layer CO measurements with unit ppb (parts per billion).
A recent article published in PNAS points out that efforts to reduce nitrogen dioxide and carbon monoxide emissions between 2011 – 2015 have slowed in the United States, despite previous estimates that emissions were decreasing. These “bottom-up” estimates used ground-based measurements, inventories and models to predict these smog-producing emissions. However, when viewed from above, through satellite data from MOPITT and OMI, both nitrogen dioxide and carbon monoxide levels have not decreased.
Researchers concluded that emissions, especially for nitrogen dioxide, have not decreased as thought because of vehicle and industrial emissions. Industrial and construction equipment emissions are growing, while heavy duty truck diesel emissions may have been overlooked in ground-based measurements. Car emissions also continue to be a pollution source, but are now contributing a smaller proportion of total emissions.
One thing is certain, that viewing from above gives scientists the opportunity to see the whole United States, instead of relying on site specific ground based measurements.
Read more about it in the news:
Los Angeles Times: Slowdown in emissions reductions could explain stalled progress on smog, study finds
Bloomberg: Your air isn’t getting as clean as the EPA said it is
USA Today: The USA’s long battle against air pollution isn’t over yet, as air quality improvements are slowing down
Associated Press (on Tampa Bay Times website): America’s air isn’t getting cleaner as fast as it used to
MISR with it’s multiple angled views of the Tinder fire, makes it uniquely capable of tracking the plume height and direction of one of the first fires of the 2018 season in the United States. The fire started on April 27th, 2018 from an abandoned campsite and quickly spread through, Cococino National Forest in, eastern Arizona. This MISR data is from April 30th, 2018, showing the plume height and direction. The plume reached nearly 4 kilometers high near the source of the fire. Typically the higher a plume reaches, the further the impact extends. Scientists are using data like this to better understand how fires impact air quality beyond the source area.
Using Satellites to Track the Tinder Fire on NASA Earth Observatory
Tinder Fire in Arizona Viewed by NASA’s MISR from JPL’s Photojournal
The excellent health and longevity of the Terra platform and its five instruments has led to the enviable problem of deciding how best to manage fuel usage of the platform over the next five years. The decision will directly impact both the continuity of the Terra science record and the length of time that Terra will remain on orbit. The Project is looking to better understand the possible benefits to the science community from different fuel use scenarios and welcomes feedback.
The question that poses itself now is whether to use all of the remaining maneuvering fuel to maintain Terra’s current orbit and keep the equator crossing-time at 10:30 AM (within a tight time window of 10:29 AM to 10:31AM local time) which will lead to nearly 3 more years of continuous climate quality data or to use some of the fuel to lower the orbit leading to an earlier re-entry of Terra. The earlier re-entry decreases the probability that Terra will be impacted by space debris, although all orbiting satellites are at risk of being hit by debris and rely on collision avoidance maneuvers to minimize this risk. Terra will maintain fuel reserve to perform these maneuvers after lowering or exiting the constellation to minimize risk of collision.
A major impact of lowering Terra’s orbit is a change in its crossing time. A body of scientists acquainted with Terra’s instruments concluded that a “change in the crossing-time would mark the end of Terra’s ‘climate quality’ data record for trend analysis”. The panel stipulated that the magnitude of the impact would be of the same order as the trends projected by climate models. The fact that Terra still has five healthy instruments providing a continuous well-calibrated, inter-calibrated, data record led the panel to conclude “that it is of utmost importance to continue this data record while the Terra instruments are performing nearly optimally.”
In order to provide a data set of the best quality for the science community, the Terra Project Science Office, including the five instrument teams, recommended that the current crossing-time be held until fall 2020. Doing so, would sustain an equatorial crossing time within a two-minute window for an unprecedented 18 years while still allowing a safe exit from the Earth Science Constellation. The use of fuel to maintain Terra’s crossing-time until fall 2020 leads to a predicted additional 18 years on orbit and a corresponding marginal increase in the probability of a debris impact. The science possible from a near-constant crossing time for 18 years is unique and viewed to offset the added risks involved from the additional time on orbit. What is not clear to the Terra Mission, however, is whether there are science applications that would benefit from either a shift in crossing time or an orbit lowering. The Project is currently searching for possible science benefits from the orbit lowering and plans to hold a panel discussion at the American Geophysical Union’s annual meeting in December, 2017.
The Terra Science Team welcomes any feedback or suggestions as to whether to maintain the current orbit and the long-term data continuity, or lower the orbit, and therefore, shifting the crossing time.
** Note that Terra did not come to maintain a consistent 10:30 am crossing time until 2 years after its launch.
Please leave any feedback or suggestions by contacting us. All comments will be considered in our panel discussion on December 10. Comments left after December 10 will be considered prior to Terra’s next planned inclination maneuver.
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