I thought the March Puzzler would be an easy one, but it turned out to be one of the more difficult we’ve posted. As explained in our March 29, 2014, Image of the Day, the image shows Nalabana Bird Sanctuary in India’s Chilika Lake. Despite more than 50 guesses on Earth Matters and 500 on Facebook, nobody came up with the exact location. However, many readers (including Steve Martin and Wendy Spiteri) did recognize the shrimp farms or that it was somewhere in India.
I kept the caption to a few paragraphs, but there’s a lot more that could be written about Chilika Lake. It’s a beautiful and fascinating place that faces environmental, economic, and political challenges that are as complicated as anywhere in the world. In 2002, for instance, authorities dredged a new connection with the Bay of Bengal after silt narrowed the existing mouth and made it more difficult for salty water to enter the lake. While the new mouth increased salinity levels, it did little to resolve the pitched debate between shrimp farmers and traditional fishing communities that has simmered for years. In 1996, the Supreme Court of India banned aquaculture within 1,000 meters (3,300 feet) of Chilika Lake because of environmental concerns, yet enclosures known as “gheries” (which are even visible to satellites…see page 50 of this Powerpoint) remain widespread. You can read more about the ongoing debate about aquaculture in Chilika Lake from Infochange,Economic Times,Radio Netherlands, and the Times of India.
On March 25, 2014, we published this nadir view of debris and a barrier lake created by a major landslide near Oso, Washington; the image was acquired by the Landsat 8 satellite on March 23. While top-down satellite views are Earth Observatory’s specialty, such images can be challenging to interpret because of how foreign the scale and topography appear from above as compared to how we normally see the world from the ground. To help make the nadir perspective more intuitive, I try to share matching aerial or ground photography when it is available. The set of images below, originally published by the office of Washington State Governor Jay Inslee, was taken during an aerial survey on the same day that Landsat 8 acquired its image. For more photographs of the landslide, visit Inslee’s Flickr page.
It’s funny what you can find in a satellite image. Mike Gartley, a research scientist at Rochester Institute of Technology, spotted the Landsat 5 satellite lurking in a Landsat 8 image of northwestern Brazil.
Landsat 5 is just a few blurry pixels in Landsat 8’s panchromatic band.
Landsat 5 once flew in the orbit that Landsat 8 now lives in. But in January 2013, the U.S. Geological Survey lowered L5’s orbit about 23 kilometers (14 miles) as part of the decommissioning process. The satellite is now in a disposal orbit, slowly being dragged back to Earth.
Landsat 8, meanwhile, reached its final orbiting altitude of 705 kilometers (438 miles) on April 12, 2013. On November 22, Landsat 8 flew over the defunct Landsat 5 satellite, capturing this view of its predecessor. Landsat 5 is just a few pixels across and is only visible at all because it is much closer to Landsat 8 than it is to Earth. See additional images from the November 22 overflight on NASA’s Landsat web site.
Finding Landsat 5 in the image was a matter of course for Gartley, who routinely hunts for space objects in Landsat images. As of December 2011, more than 22,000 “resident space objects” were in orbit around the Earth. The Space Surveillance Network tracks all of these objects with telescopes, radars, and a computer model. Gartley uses this information to figure out when an object will fly into Landsat 8’s view.
“Believe it or not, there are anywhere from 1 to 4 such underflights of space objects that are passing through the field of view of Landsat 8 on any given day,” says Gartley. “Many of the objects are old rocket bodies and COSMOS satellites (Tselina-D ELINT type), while the ISS has also popped up at least three times since last May.”
The International Space Station seen from Landsat 8.
Landsat 5’s appearance is appropriate: it’s the satellite that just won’t go away. The tenacious satellite was built to operate for 3 years, but worked for more than 29, setting a world record for the longest operating Earth observation satellite. Even the decommissioning process took longer than expected because the satellite kept running. Hear the story from longtime flight systems manager for Landsat 5, Steve Covington, in this recorded talk originally given at the Library of Congress:
Las imágenes de satélite son como los mapas: están llenas de información útil e interesante, siempre y cuando tengas una clave. Éstas nos pueden mostrar cuánto ha cambiado una ciudad, cuán bien están creciendo nuestros cultivos, dónde arde un fuego o cuando se acerca una tormenta. Para revelar la riqueza de información en una imagen de satélite haz lo siguiente:
1. Busca una escala
2. Busca patrones, formas y texturas
3. Define los colores (incluyendo las sombras)
4. Encuentra el norte
5. Considera tu conocimiento previo
Estos consejos provienen de escritores y visualizadores de NASA Earth Observatory que los utilizan diariamente para interpretar imágenes de satélite. Te ayudarán a orientarte lo suficiente para extraer información valiosa de imágenes de satélite.
Following their successful “Let It Snow” photo contest, our colleagues at the soon-to-launch Global Precipitation Measurement (GPM) mission are looking for your best photos and videos of rain, sleet, hail, snow and any other precipitation. They describe their “Unique Perspectives” contest this way:
There are many ways to view precipitation…We’d like to see weather from all angles — far away, up close, above, below and inside. The more creative and unique, the better. Post your coolest photos and videos of precipitation from unique perspectives, and we’ll choose the best ones to post on the NASA Precipitation Measurement Missions websites…Winning photos will be selected by a group of judges comprised of NASA scientists and outreach personnel, and will be judged based on their creativity and artistic merit.
The new contest runs from November 1 to December 1, 2013, and imagery can be submitted via Flickr, Instagram, or Vimeo. Learn more about the contest and rules by visiting: http://pmm.nasa.gov/unique-perspectives
Engineer and avid traveler Andrew Bossi had one of the winning entries last spring – this shot of the harbor in Kulusuk, Greenland. His shot became part of an Image of the Day on Earth Observatory.
In between combing your photo archives and setting up your tripod for the perfect precipitation shot, check out this quirky anime cartoon about GPM from the science and outreach team at JAXA, NASA’s partner in the mission. If you don’t speak Japanese, turn on the closed-caption button.
While most of NASA went dark during the government shutdown, life went on at the International Space Station. Throughout October, astronauts Karen Nyberg, Mike Hopkins, and Luca Parmitano sent a steady stream of tweets back to Earth. The most eye-popping of the bunch came from Hopkins, who tweeted this on October 10, 2013: “Saw something launch into space today. Not sure what it was, but the cloud it left behind was pretty amazing.”
It turns out it was a Russian missile launch, according to bloggers at the Russian Nuclear Forces Project. The group noted: “The Strategic Rocket Forces carried out a successful test launch of a Topol/SS-25 missile on October 10, 2013. The missile was launched at 17:39 MSK (13:39 UTC) from Kapustin Yar to the Sary Shagan test site in Kazakhstan. According to a representative of the Rocket Forces, the test was used to confirm characteristics of the Topol missile, to test the systems of the Sary Shagan test site, and ‘to test new combat payload for intercontinental ballistic missiles.’ ”
Hopkins’ colleague, European Space Agency astronaut Luca Parmitano, also captured the remarkable shot below, which shows the missile’s contrail being yanked back and forth by winds at different levels of the atmosphere. Discovery News,University Today, and Fox News have more coverage.
We’re sorry, but we will not be posting updates to this blog during the government shutdown. Also, all public NASA activities and events are cancelled or postponed until further notice. Rest assured that we will be back as soon as possible! We hope that you will stick with us and we promise more great imagery when we return. Please note that we will not be moderating or posting comments until the shutdown is over.
See you on the other side,
Kevin, Mike, Adam, Holli, Jesse, Rob, and Paul
The Earth Observatory Team
+Warming of the climate system is unequivocal, and since the 1950s, many of the observed changes are unprecedented over decades to millennia. The atmosphere and ocean have warmed, the amounts of snow and ice have diminished, sea level has risen, and the concentrations of greenhouse gases have increased. Read more about global warming.
+Each of the last three decades has been successively warmer at the Earth’s surface than any preceding decade since 1850. In the Northern Hemisphere, 1983–2012 was likely the warmest 30-year period of the last 1400 years. See maps showing global temperature trends.
+Ocean warming dominates the increase in energy stored in the climate system, accounting for more than 90% of the energy accumulated between 1971 and 2010 (high confidence). It is virtually certain that the upper ocean (0−700 m) warmed from 1971 to 2010, and it likely warmed between the 1870s and 1971. Read more about Earth’s energy budget.
+Over the last two decades, the Greenland and Antarctic ice sheets have been losing mass, glaciers have continued to shrink almost worldwide, and Arctic sea ice and Northern Hemisphere spring snow cover have continued to decrease in extent (high confidence). Read more about Arctic and Antarctic sea ice.
+The rate of sea level rise since the mid-19th century has been larger than the mean rate during the previous two millennia (high confidence). Over the period 1901–2010, global mean sea level rose by 0.19 [0.17 to 0.21] m. Read more about sea level rise.
+The atmospheric concentrations of carbon dioxide (CO2), methane, and nitrous oxide have increased to levels unprecedented in at least the last 800,000 years. CO2 concentrations have increased by 40% since pre-industrial times, primarily from fossil fuel emissions and secondarily from net land use change emissions. The ocean has absorbed about 30% of the emitted anthropogenic carbon dioxide, causing ocean acidification. Read more about the greenhouse effect.
+Total radiative forcing is positive, and has led to an uptake of energy by the climate system. The largest contribution to total radiative forcing is caused by the increase in the atmospheric concentration of CO2 since 1750. Read more about radiative forcing.
+Climate models have improved since the AR4. Models reproduce observed continental-scale surface temperature patterns and trends over many decades, including the more rapid warming since the mid-20th century and the cooling immediately following large volcanic eruptions (very high confidence). Read more about climate models.
+Observational and model studies of temperature change, climate feedbacks and changes in the Earth’s energy budget together provide confidence in the magnitude of global warming in response to past and future forcing. Read more about Earth’s energy budget.
+Human influence has been detected in warming of the atmosphere and the ocean, in changes in the global water cycle, in reductions in snow and ice, in global mean sea level rise, and in changes in some climate extremes. This evidence for human influence has grown since AR4. It is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century. Read more about the human influence on climate.
+Continued emissions of greenhouse gases will cause further warming and changes in all components of the climate system. Limiting climate change will require substantial and sustained reductions of greenhouse gas emissions. Read more about greenhouse gases.
+Global surface temperature change for the end of the 21st century is likely to exceed 1.5°C relative to 1850 to 1900 for all RCP scenarios except RCP2.6. It is likely to exceed 2°C for RCP6.0 and RCP8.5, and more likely than not to exceed 2°C for RCP4.5. Read more about global surface temperatures.
+Changes in the global water cycle in response to the warming over the 21st century will not be uniform. The contrast in precipitation between wet and dry regions and between wet and dry seasons will increase, although there may be regional exceptions. Read more about the water cycle.
+It is very likely that the Arctic sea ice cover will continue to shrink and thin and that Northern Hemisphere spring snow cover will decrease during the 21st century as global mean surface temperature rises. Global glacier volume will further decrease. Read more about sea ice.
+Global mean sea level will continue to rise during the 21st century. Under all RCP scenarios the rate of sea level rise will very likely exceed that observed during 1971–2010 due to increased ocean warming and increased loss of mass from glaciers and ice sheets. Read more about sea surface temperature.
+Climate change will affect carbon cycle processes in a way that will exacerbate the increase of CO2 in the atmosphere (high confidence). Further uptake of carbon by the ocean will increase ocean acidification. Read more about the ocean’s carbon balance.
+Cumulative emissions of CO2 largely determine global mean surface warming by the late 21st century and beyond. Most aspects of climate change will persist for many centuries even if emissions of CO2 are stopped. This represents a substantial multi-century climate change commitment created by past, present and future emissions of CO2. Read more about carbon dioxide.
Tropical cyclone “heat engines” extract heat from the ocean’s surface through evaporation and convert a portion of that energy into destructive winds that circle under the eyewall of the storm. All tropical cyclones have heat engines, but several features detected by TRMM suggested that Usagi’s was running particularly efficiently. Radars almost always see eyewalls in strong tropical cyclones, for instance, but they are rarely as symmetrical as Usagi’s is in the visualization shown above. NASA Goddard Space Flight Center researcher Owen Kelley produced the visualization based on TRMM data from the Precipitation Measurement Missions science team at NASA and from the Japan Aerospace Exploration Agency (JAXA).
In the 3D portion of the image, heavy precipitation is shown in dark red. Light precipitation is gray, green, yellow or light red, with the color reflecting how high the storm has lofted the rain production (higher than 8.5 kilometers is green; above 11.5 kilometers is yellow; and higher than 14 kilometers is red). Note that the underlying image, which shows the temperature of cloud tops, uses a different color scale. In it, cool cloud tops are pink and white, medium temperature cloud tops are gray and blue, and warm cloud tops are dark gray and black.
Even the heavy precipitation at the base of the eyewall is fairly symmetric, which is somewhat unusual according to Kelley. Tropical cyclone eyewalls that are this symmetric are called “annular,” and they have a tendency to maintain their intensity for longer periods than tropical cyclones with more lopsided eyewalls. At two locations in the inner eyewall, updrafts were strong enough to produce hot towers—features that are associated with strengthening cyclones. A few hours after TRMM collected the data visualized here, Usagi intensified briefly into a category 5 storm, the highest category on the scale.
Yesterday’s Image of the Day — Ocean Revealed — elicited an interesting response from Norman Kuring, a NASA oceanographer who frequently contributes to the Earth Observatory. He notes:
“There have indeed been a number of studies that exploit sunglint for ocean research since Paul Scully-Power made his statement. However, I disagree with the follow-on sentence that, “his observation holds true for satellite observations today.” While sunglint does reveal some information about the ocean beneath, for visible radiometry sensors it usually obscures more than it reveals.”
“We in the ocean-color community often bemoan the fact that the MODIS instruments and VIIRS do not tilt to avoid the worst of the glint field. SeaWiFS, which was primarily an ocean mission, tilted, and the upcoming ocean radiometer on PACE is also planned to be tiltable to avoid the worst of the glint.”
Good point, Norman. Sunglint hides the telltale shades of blue and green that point to phytoplankton growth in the ocean’s surface waters. Here’s a good example, originally published on the Earth Observatory in 2007.
Notice how the bright sunglint obscures the color on the top and right side of the image. (NASA’s Ocean Color web site provides another good example with a more detailed description.) It’s no wonder that oceanographers like Norman cringe at the thought of sunglint in ocean images.