Jump to content


  • Posts

  • Joined

  • Last visited

  • Days Won


Lurker last won the day on December 5

Lurker had the most liked content!

About Lurker

  • Birthday 02/13/1983

Profile Information

  • Gender
  • Location
  • Interests
    GIS and Remote Sensing

Recent Profile Visitors

The recent visitors block is disabled and is not being shown to other users.

Lurker's Achievements

  1. really nice storymaps my friend, btw, what is your current licence for your arcgis storymaps? https://doc.arcgis.com/en/arcgis-storymaps/reference/licensing.htm
  2. A new study published today by journal PLOS ONE has revealed that mountaintop removal mining poses a more serious and widespread threat to endangered species and people than was previously understood. The researchers from Defenders of Wildlife's Center for Conservation Innovation (CCI) and conservation technology nonprofit SkyTruth, combine water-quality data with satellite imagery of mountaintop removal mining activity to estimate the full extent of water-quality degradation attributable to the practice at the landscape level. "This research really emphasizes the interconnectedness of ecosystems and how distant human activity can have ripple effects that aren't immediately apparent," said CCI's Senior Conservation Data Scientist Mike Evans. "Being able to assess impacts at a landscape scale opens a completely new door for conservation." Mountaintop removal is a coal-mining method that clearcuts forests and then uses explosives to remove top soil and bedrock, which is often dumped in nearby valleys. The method's negative impacts on water quality is well known, but this research is now revealing the extent of the damage. The research found that chronic and acute toxicity thresholds for chemicals like aluminum, copper, lead and manganese as well as acidity levels in streams were exceeded thousands of times—including in areas of critical habitat—far removed from where the mines actually are. Previously, it was thought impacts were contained to the immediate area around mines. The study combined 30 years of satellite imagery data that mapped large surface mines in central Appalachia and water-quality measurements from more than 4,000 monitoring sites across different watersheds. "We have been watching mountaintop removal mining expand across the Appalachian landscape for years using satellite imagery," said Christian Thomas, geospatial engineer with SkyTruth. "By combining our imagery with water-quality data, we have finally revealed how profoundly this activity harms sensitive aquatic species." Central Appalachia is a highly biodiverse region and the streams impacted by these mines contain many threatened and endangered species, including 39 mollusk species, 12 fish, as well as crustacean and snail species. The region includes parts of Kentucky, Tennessee, Virginia, and West Virginia where this mining often occurs. "More than 50 federally protected species inhabit the streams of this region, and we haven't historically known the full impact of these mines, until now," said Evans. "This research expands the ability for state and federal agencies to make better decisions that directly affect vulnerable people and wildlife." The results of this study and the same methods can now be used to improve protections for imperiled species and provide a more rigorous scientific standard for mine permitting practices going forward by representing "best-available science," the legal standard required under the Endangered Species Act. source: https://phys.org/news/2021-11-mountaintop-worse-endangered-species-thought.html
  3. DJI is best known for drones, but it's possibly the most inventive camera company right now. After unveiling the outrageous full-frame Ronin 4K camera/gimbal last month, it has now launched the $2,200 Mavic 3 drone with not just one, but two innovative camera systems. As rumored, there are two models in the Mavic 3 family, the Standard and Cine models, along with a "Fly More" combo that bundles more accessories. The main difference is that the Mavic 3 Cine has a built-in 1TB SSD and supports Apple ProRes 422 HQ video recording — highly desirable for professional film productions. The latter is also considerably more expensive, as I'll discuss shortly. The Mavic 3's main 24mm (35mm-equivalent) f/2.8 - f/11 Hasselblad-branded camera has a Four Thirds sensor that's considerably larger than the 1-inch sensor on the current Air 2S model. And yet, the camera module doesn't look much bigger and the Mavic 3 weighs slightly less than the Mavic 2 (895g compared to 907g). Four Thirds is the same size as the Micro Four Thirds sensor on Panasonic's BGH1 box camera, for example, so it should allow for more cinematic video and photos. The variable aperture, along with optional ND filters, will make it easier to shoot in a variety of lighting conditions. It also comes with a new autofocus system called Vision Detection that supposedly optimizes focusing speeds. With the main camera, it now shoots 5.1K video at 50fps, or 4K at 120 fps — up from 5.4K 30fps and 4K/60p video on the Air 2S. DJI claims a native dynamic range of 12.8 stops, thanks to the 10-bit D-Log color profile. As for still images, it can shoot 20-megapixel photos in 12-bit RAW. If you need to get in much, much closer, DJI has squeezed in a second camera directly above the main camera. This one has a half-inch 12-megapixel sensor and 162mm tele lens (35mm equivalent), which is around a 4X zoom, or claimed 28X hybrid zoom. The aperture is fixed at f/4.4, and it offers strictly automatic, rather than manual exposure control. It can capture 4K video at up to 30 fps. DJI has confirmed that the Mavic 3 will have up to 46 minutes of autonomy in ideal conditions (40 minutes of hover), as leaks had suggested. That's up pretty massively from the Mavic 2 Pro or Air 2S, both of which offer 31 minutes of flying time. It can also fly a bit faster too, at 47 MPH compared to 45 MPH. Those capabilities were enabled by a higher-capacity battery, more energy-efficient motors/propellers and a more streamlined shape on the Mavic 3's arms, body and gimbal. "Wind tunnel testing shows Mavic 3 produces 35 percent less drag than previous generations," DJI wrote. The Mavic 3 also offers enhanced flight safety thanks to its updated APAS 5.0 system that uses inputs from six fish-eye vision sensor and two wide-angle sensors to detect and avoid obstacles. Meanwhile, the ActiveTrack 5.0 system has new options for tracking subjects no matter which way they're moving, and it can even continue to track a subject if it moves out of frame and pick it back up when it reappears. All of that allows "more fluid and diverse drone and camera movement," DJI said. It also comes with an improved RTH (Return to Home) system that works by automatically calculating the shortest, safest and most energy-efficient route to land back at its home point. It can take into account wind speed and power when calculating the path, giving users a bit more flying time before triggering the RTH action. Another updated feature is O3+ signal loss prevention that allows for a maximum control range of 15 km. Mavic 3 is also DJI's first drone with a 1080p 60fps transmission speed on the live feed, meaning "the camera view is displayed at a resolution close to what the camera actually records," DJI notes. Along with the drone, DJI introduced a number of new accessories, including a new DJI RC Pro smart controller, a 65W Portable Charger that's compatible with notebooks and smartphones and allows for fast charging (around 96 minutes), a wide-angle lens and two sets of ND filters (ND4/8/16/32 and ND64/128/256/512) that allow for shooting in bright sunlight. It also introduced a carrying bag that converts into a backpack that can fit the drone, a laptop and other accessories. Engadget received the drone just yesterday, so we haven't had a chance to fly it yet — stay tuned for a full review. However, I'm impressed so far by the design and small details like the storage cover that protects the camera, gimbals and propeller (below). It's also clear that DJI has put a lot of thought into the new charging system and batteries that should make operation more practical. Even the carrying bag/backpack is well conceived, with pockets and sleeves for the batteries, ND filters and more. source: https://www.engadget.com/dj-is-mavic-3-squeezes-in-a-four-thirds-and-28-x-hybrid-zoom-camera-023041720.html
  4. Kleos Space S.A (ASX:KSS, Frankfurt:KS1, Kleos or Company), a space-powered Radio Frequency Reconnaissance data-as-a-service (DaaS) company, has signed new contracts with satellite builder Innovative Solutions in Space B.V. (ISISPACE) and global launch services provider Spaceflight Inc to build and manage the launch its fourth satellite cluster of four satellites, the Observer Mission (KSF3) mid-2022. Kleos Space CEO Andy Bowyer said, “We are rapidly building our constellation, utilising funds from our recent capital raise to commit to our fourth satellite cluster build and launch. Each new launch enables us to improve satellite data collection and increase revisits over key areas of interest for our customers. The Observer Mission increases the revenue opportunity from existing subscribers and caters to the needs of our growing global pipeline. Spaceflight and ISISPACE have proven to be effective partners for both our Vigilance Mission and upcoming Patrol Mission launch. We are leveraging their experience to accelerate the build and launch of our Observer Mission.” Kleos’ fourth satellite cluster complements the 37-degree orbit of the ‘Scouting Mission’ and Sun Synchronous orbits of the ‘Vigilance Mission’ and ‘Patrol Mission’ satellites with up to a further 119 million km2 data collection capacity per day (Vigilance and Patrol Missions each have similar data collect capacity). Netherlands-based ISISPACE will provide Kleos with a turn-key solution for its four Observer Mission satellites, including design, development, production, testing, launch integration services, and support for checkout and commissioning”. ISISPACE has more than 15 years’ nanosatellite experience, successfully built Kleos’ ‘Vigilance Mission’ (KSF1) and is currently building the ‘Patrol Mission’ (KSF2) satellites. Jeroen Rotteveel, CEO of ISISPACE, said, “We are proud to be expanding our strategic partnership with Kleos to build and support the launch of their fourth satellite cluster. Our extensive nanosatellite experience spans design, manufacturing and operation complementing Kleos’ in-house engineering expertise. We look forward to continuing to work with Kleos to increase satellite capability, leveraging learnings from earlier launches.” Spaceflight provided the integration, mission management, and launch services for the successful launch of the Vigilance Mission satellites on its SXRS-5 mission in June 2021 and has already been engaged by Kleos for the upcoming Patrol Mission launch. Marcy Mabry, Spaceflight’s Mission Manager added, “We are delighted to be working with Kleos again to launch its small satellite payload into a 500-600km Sun Synchronous orbit. Our portfolio of frequent launch options provides unmatched flexibility and reliability, ensuring Kleos’ growing constellation gets to orbit when and where they want. Kleos’ satellite technology addresses a real-world need, providing precision geolocation data to improve situational awareness and disrupt illegal activity.” Kleos successfully launched its Scouting Mission and Vigilance Mission satellites in November 2020 and June 2021 respectively. Its Patrol Mission satellites are progressing through the build process and on track for an expected January 2022 launch onboard a SpaceX Falcon 9. Identical to the upcoming Patrol Mission satellites (KSF2), the Observer Mission will provide increased capacity and more frequent revisit times. Each new cluster increases Kleos’ sensing and intelligence gathering capacity, generating potential for higher-value data products and tiered subscription licenses. Kleos’ satellites detect and geolocate radio frequency transmissions to improve the intelligence, surveillance, and Reconnaissance (ISR) capabilities of governments and commercial entities. Its independent geolocation data enhances the detection of illegal activity, including piracy, drug and people smuggling, border security challenges and illegal fishing, and is available to qualified subscribers as-a-service. Final mission costs incurred are anticipated to be comparable with publicly available satellite build and space rideshare costs and within the envelope of the cost of a launch advised within the prospectus. source: Kleos commits to build and launch fourth satellite cluster « Earth Imaging Journal: Remote Sensing, Satellite Images, Satellite Imagery
  5. nice, i feel some improving on performance here thank you admin
  6. The National Oceanic and Atmospheric Administration has shared what it says are the first images and video captured inside a hurricane by a surface drone. The agency placed the Saildrone Explorer SD 1045 in the path of the category-four Hurricane Sam. The saildrone overcame 50-foot waves and winds at speeds topping 120 miles per hour to capture data from the hurricane and offer a new perspective into such storms. The device has a special “hurricane wing” to help it survive the intense wind conditions. The SD 1045 is one of five saildrones that have been in the Atlantic Ocean during hurricane season. They are constantly recording data to help researchers gain a deeper understanding into hurricanes. The information could help improve storm forecasting, which will hopefully reduce the loss of lives when hurricanes make landfall. “Using data collected by saildrones, we expect to improve forecast models that predict rapid intensification of hurricanes,” Greg Foltz, a scientist at NOAA, said in a statement. “Rapid intensification, when hurricane winds strengthen in a matter of hours, is a serious threat to coastal communities. New data from saildrones and other uncrewed systems that NOAA is using will help us better predict the forces that drive hurricanes and be able to warn communities earlier.” source: https://www.engadget.com/drone-video-capture-hurricane-sam-170906138.html
  7. hello, welcome to the forum could you explain in details the problem you face? and maybe some screenshoot would help us
  8. The quality and cost of broadband remain issues for households across the US, and the Biden administration wants to draw attention to that unfortunate reality. The National Telecommunications and Information Administration (NTIA) has published what it says is the first interactive public map detailing the "digital divide" in broadband access. You'll not only see areas where broadband speeds fall below official targets (25Mbps down and 3Mbps up), but correlate that with high-poverty areas. You can look for specific locations, including Tribal lands and minority-serving institutions. As you can see from the image above, the map isn't particularly flattering. The performance shortfalls are spread across the country, and aren't as concentrated in specific areas as you might think. There's a political motivation behind the map, of course. Commerce Secretary Gina Raimondo saw this as supporting President Biden's American Jobs Plan, which includes a "once-in-a-lifetime" effort to connect everyone in the country with fast, affordable internet access. It's also a not-so-subtle criticism of the previous administration, suggesting that past rural broadband efforts didn't do enough to meaningfully close gaps in internet service. Of course, changing this map for the better won't be easy. In addition to any political hurdles, officials need to refine broadband maps and secure the cooperation of internet providers that haven't always been eager to serve rural and low-income areas. The data merely underscores the problem — it's another matter entirely to fix it.
  9. When humans pump large volumes of fluid into the ground, they can set off potentially damaging earthquakes, depending on the underlying geology. This has been the case in certain oil- and gas-producing regions, where wastewater, often mixed with oil, is disposed of by injecting it back into the ground—a process that has triggered sizable seismic events in recent years. Now MIT researchers, working with an interdisciplinary team of scientists from industry and academia, have developed a method to manage such human-induced seismicity, and have demonstrated that the technique successfully reduced the number of earthquakes occurring in an active oil field. Their results, appearing today in Nature, could help mitigate earthquakes caused by the oil and gas industry, not just from the injection of wastewater produced with oil, but also that produced from hydraulic fracturing, or "fracking." The team's approach could also help prevent quakes from other human activities, such as the filling of water reservoirs and aquifers, and the sequestration of carbon dioxide in deep geologic formations. "Triggered seismicity is a problem that goes way beyond producing oil," says study lead author Bradford Hager, the Cecil and Ida Green Professor of Earth Sciences in MIT's Department of Earth, Atmospheric and Planetary Sciences. "This is a huge problem for society that will have to be confronted if we are to safely inject carbon dioxide into the subsurface. We demonstrated the kind of study that will be necessary for doing this." The study's co-authors include Ruben Juanes, professor of civil and environmental engineering at MIT, and collaborators from the University of California at Riverside, the University of Texas at Austin, Harvard University, and Eni, a multinational oil and gas company based in Italy. Safe injections Both natural and human-induced earthquakes occur along geologic faults, or fractures between two blocks of rock in the Earth's crust. In stable periods, the rocks on either side of a fault are held in place by the pressures generated by surrounding rocks. But when a large volume of fluid is suddenly injected at high rates, it can upset a fault's fluid stress balance. In some cases, this sudden injection can lubricate a fault and cause rocks on either side to slip and trigger an earthquake. The most common source of such fluid injections is from the oil and gas industry's disposal of wastewater that is brought up along with oil. Field operators dispose of this water through injection wells that continuously pump the water back into the ground at high pressures. "There's a lot of water produced with the oil, and that water is injected into the ground, which has caused a large number of quakes," Hager notes. "So, for a while, oil-producing regions in Oklahoma had more magnitude 3 quakes than California, because of all this wastewater that was being injected." In recent years, a similar problem arose in southern Italy, where injection wells on oil fields operated by Eni triggered microseisms in an area where large naturally occurring earthquakes had previously occurred. The company, looking for ways to address the problem, sought consulation from Hager and Juanes, both leading experts in seismicity and subsurface flows. "This was an opportunity for us to get access to high-quality seismic data about the subsurface, and learn how to do these injections safely," Juanes says. Seismic blueprint The team made use of detailed information, accumulated by the oil company over years of operation in the Val D'Agri oil field, a region of southern Italy that lies in a tectonically active basin. The data included information about the region's earthquake record, dating back to the 1600s, as well as the structure of rocks and faults, and the state of the subsurface corresponding to the various injection rates of each well. The researchers integrated these data into a coupled subsurface flow and geomechanical model, which predicts how the stresses and strains of underground structures evolve as the volume of pore fluid, such as from the injection of water, changes. They connected this model to an earthquake mechanics model in order to translate the changes in underground stress and fluid pressure into a likelihood of triggering earthquakes. They then quantified the rate of earthquakes associated with various rates of water injection, and identified scenarios that were unlikely to trigger large quakes. When they ran the models using data from 1993 through 2016, the predictions of seismic activity matched with the earthquake record during this period, validating their approach. They then ran the models forward in time, through the year 2025, to predict the region's seismic response to three different injection rates: 2,000, 2,500, and 3,000 cubic meters per day. The simulations showed that large earthquakes could be avoided if operators kept injection rates at 2,000 cubic meters per day—a flow rate comparable to a small public fire hydrant. Eni field operators implemented the team's recommended rate at the oil field's single water injection well over a 30-month period between January 2017 and June 2019. In this time, the team observed only a few tiny seismic events, which coincided with brief periods when operators went above the recommended injection rate. "The seismicity in the region has been very low in these two-and-a-half years, with around four quakes of 0.5 magnitude, as opposed to hundreds of quakes, of up to 3 magnitude, that were happening between 2006 and 2016," Hager says. The results demonstrate that operators can successfully manage earthquakes by adjusting injection rates, based on the underlying geology. Juanes says the team's modeling approach may help to prevent earthquakes related to other processes, such as the building of water reservoirs and the sequestration of carbon dioxide—as long as there is detailed information about a region's subsurface. source: https://phys.org/news/2021-07-earthquakes-triggered-oil-production-scientists.html
  10. On February 7, 2017, the twentieth and final inclination (Delta-I) maneuver of Landsat 7 took place. (Delta-I maneuvers keep the spacecraft in the correct orbital position to ensure it maintains its 10:00 am ± 15 minutes mean local time (MLT) equatorial crossing.) Landsat 7 reached its peak outermost inclination boundary of 10:14:58 MLT on August 11, 2017. Landsat 7 is now drifting in its inclination and will fall back to 09:15 am MLT by July 2021. The chart below illustrates the inclination trend from June 2014 to June 2026. The USGS and NASA are planning for Landsat 7 to remain on-station and fulfilling its current science mission until Landsat 9 completes its launch (scheduled for September 16, 2021), on-orbit checkout, and commissioning. Sometime after Landsat 9 is nominally acquiring science mission data, Landsat 7 will exit the constellation and lower its orbit by 8 km to prepare for servicing by NASA’s On-Orbit Servicing, Assembly, and Manufacturing-1 (OSAM-1) mission. The mission - the first of its kind in low Earth orbit - will provide Landsat 7 with the needed fuel for a successful decommissioning. source: https://www.usgs.gov/core-science-systems/nli/landsat/landsat-7?qt-science_support_page_related_con=0#qt-science_support_page_related_con
  11. Many of Africa’s agricultural endeavors have long been tied to whims of the weather. When it rains, a country’s gross domestic product might soar. When it doesn’t rain, economies suffer. The reliance has been driven in part by the perception that dry, arid Africa has limited water resources. But a new study, years in the making, shows a different reality. As one South African scientist recently noted, if all the rainfall stopped today and for the next 100 years in Africa, there would still be plenty of water stored underneath the continent’s surface, it just wouldn’t be evenly distributed. That’s why maps are essential in showing which aquifers are vulnerable to rainfall variability. “You can imagine the possibilities,” said hydrologist Seifu Kebede Gurmessa from the University of KwaZulu-Natal in South Africa and coauthor of the study. The study, released in February, uses maps from a geographic information system (GIS) analysis to show water replenishment across the continent. It turns out that the vast majority of Africa’s countries either have high water storage or high levels of groundwater replenishment. Five countries have both. Five have neither. “We say we are prisoners of the rainfall,” Gurmessa said of Africa’s dependence on the resource for agriculture, one of the continent’s largest economic outputs. Little groundwater, proportionately, is used for irrigation currently. “How can we break that imprisonment of seasonality in the rainfall?” Groundwater use could be a buffer for the stark seasonal swings. Important Water Discoveries The report, Mapping Groundwater Recharge in Africa from Ground Observations and Implications for Water Security, was led by the British Geological Survey (BGS) and is a sequel to another of the BGS’s groundbreaking studies. Using a geographic information system to aggregate information and perform spatial analysis, the report’s authors brought old data into the present by incorporating factors that impact groundwater recharge including climate, amount of rainfall, the number of wet days in a year, land cover, vegetation health, and soil type. Nearly a decade ago, the team of international scientists created a map that showed Africa actually had a rather large volume of water hidden and stored underneath the surface. However, the researchers behind the science-shifting report and, later, the BGS’s Africa Groundwater Atlas knew that that was only part of the continent’s water story. Groundwater, like a bank account, depends on regular deposits to balance withdrawals. Once again, results of the latest research were promising. The study’s authors were able to clearly map, for the first time, which countries had sustainable resources and which ones didn’t. The countries were separated into four color-coded categories: low storage/low recharge, high storage/low recharge, low storage/high recharge, and high storage/high recharge. “That map is really key in proposing what you can do in different countries,” Gurmessa said. Click on the image to see a larger map of groundwater recharge and storage in African countries. Most countries had one or the other—high storage or high recharge. Alan MacDonald, the study’s leader and a hydrogeologist with the British Geological Survey, has called it a happy symmetry. “Still,” he said, “so many people in Africa don’t have any access to safe water.” He and the others involved hope their comprehensive research starts a conversation—just like their first report did in 2012—about what’s possible and what isn’t. For instance, what kind of access to water should be installed in a village if groundwater is plentiful but rainfall is scarce? While none of the scientists involved contemplates a pumping free-for-all that could deplete groundwater, the report does suggest the continent has been faring better than might have been expected in maintaining a healthy water supply. “It’s not all doom and gloom. It’s not all bad. In some areas, there is potential for groundwater to provide safe water supplies for many more people than currently have them,” said Kirsty Upton, who oversees BGS’s Africa Groundwater Atlas. As the report itself states, “With increasing calls to draw from groundwater storage in order to stimulate economic growth and improve food security in Africa, a more nuanced approach to water security is necessary.” Making Sustainable Plans The team’s 2012 countrywide study of the continent’s groundwater conditions—a first of its kind that attracted media attention—led government ministers to hang the study’s maps from office walls. The work also encouraged funding to help 50 Africa-based partners to create a continental groundwater atlas, with data downloaded thousands of times by nongovernmental organizations, governments, students, and researchers. The study’s research and data were also the foundation for the latest groundwater recharge report, which reveals how sustainable the water supply is. “That was the next stage for us,” MacDonald said. Ten scientists including MacDonald—five in Africa and the others from around the world—promptly got to work, pouring over 320 existing studies to find the most reliable information as well as common themes. They were about to publish in 2017 until MacDonald, noticing that some of the geolocation data for the original reference studies was off, started from the very beginning again to reanalyze the information. “You want to get this right,” he said considering the importance of the data and how far its reach may be. He recalled a moment, shortly after the 2012 study on groundwater was released, when he met two French mountaineers who had a copy of the daily newspaper Le Monde. “And there was a picture of my maps,” he said. He likened the maps, including the most recent study on replenishment, to a conversation starter. Click on the image to see a larger map of African rainfall and groundwater recharge. “If you do get a map that people are really going to look at and use, you want to make sure that you’re giving them information that is useful to them and is a gateway to more information, and not misleading people,” MacDonald said. The researchers continue to be curious too, looking at additional facets. They’re already developing their next study, looking at the quality—primarily the salinity—of Africa’s groundwater. A Promising Future For the most recent study, researchers focused on long-term average groundwater recharge rates across Africa from 1970 to 2019. They used 134 existing studies deemed the most reliable, winnowing the total down from 320 and factoring in climate and terrestrial parameters to scale for the entire continent. The process wasn’t quick, easy, or highly technical. In other projects, MacDonald said, he has used data from the National Aeronautics and Space Administration (NASA) GRACE satellite, which measures water storage changes from space, averaging over a large area (400 x 400 km) to indicate whether an area’s water has been recently depleted. “But it only gets you so far,” he said, and this time the researchers needed to look in much more detail to understand water renewability on the continent. “It was sheer old-fashioned grunt work.” He and the others went through old files and maps, some found on dusty shelves. The result of this investigation—funded primarily by the UPGro research program, whose mission is Unlocking the Potential of Groundwater for the Poor—was published in Environmental Research Letters in February. “It is really a good time to be a groundwater expert in this decade in Africa,” Gurmessa said. “The future also looks more promising.” Access to and availability of water can affect a whole host of issues, ranging from school attendance to conflict that comes from agriculture workers migrating from one rural area to another, not to mention overall human health. Water is tied to everything in one’s life, he pointed out. source: https://www.esri.com/about/newsroom/blog/africa-groundwater-mapping/
  12. Classification of precipitation change regimes based on changes in the precipitation mean state and variability. Shading indicates the ratio of change in precipitation variability and mean precipitation. Climate models predict that rainfall variability over wet regions globally will be greatly enhanced by global warming, causing wide swings between dry and wet conditions, according to a joint study by the Institute of Atmospheric Physics (IAP) of the Chinese Academy of Sciences (CAS) and the Met Office, the UK's national meteorological service. This study was published in Science Advances on July 28 2021. Increased rainfall leads to floods, less rainfall to drought. Researchers realized decades ago that global warming drives increased rainfall on average. How this increase is delivered in time matters enormously. A 2 to 3 percent increase of annual precipitation uniformly spreading across the year does not mean much, but if it falls in a week or a day, it will cause havoc. Using large ensembles of state-of-the-art climate model simulations, this study highlights the increase in rainfall variability across a range of time scales from daily to multiyear. Scientists have found that in a future warming world, climatologically wet regions (including the tropics, monsoon regions and mid- to high-latitudes) will not only get wetter on average, but also swing widely between wet and dry conditions. "As climate warms, climatologically wet regions will generally get wetter and dry regions get drier. Such a global pattern of mean rainfall change is often described as 'wet-get-wetter'. By analogy, the global pattern of rainfall variability change features a 'wet-get-more variable' paradigm. Moreover, the global mean increase in rainfall variability is more than twice as fast as the increase in mean rainfall in a percentage sense," said Zhou Tianjun, corresponding author of the study. Zhou is a senior scientist at IAP. He is also a professor at the University of Chinese Academy of Sciences. The enhanced rainfall variability, to a first order, is due to increased water vapor in the air as climate warms, but is partly offset by the weakening circulation variability. The latter dominates regional patterns of change in rainfall variability. By considering changes in both the mean state and variability of precipitation, the research provides a new perspective for interpreting future precipitation change regimes. "Around two-thirds of land will face a 'wetter and more variable' hydroclimate, while the remaining land regions are projected to become 'drier but more variable' or 'drier and less variable'. This classification of different precipitation change regimes is valuable for regional adaptation planning," said Zhang Wenxia, lead author of the study. "The globally amplified rainfall variability manifests the fact that global warming is making our climate more uneven—more extreme in both wet and dry conditions, with wider and probably more rapid transitions between them," said Kalli Furtado, expert scientist at the Met Office and second author of the study. "The more variable rainfall events could further translate into impacts on crop yields and river flows, challenging the existing climate resilience of infrastructures, human society and ecosystems. This makes climate change adaptation more difficult." source: https://phys.org/news/2021-07-rainfall-increasingly-variable-climate.html
  13. Scientists from Cambridge University and NTU Singapore have found that slow-motion collisions of tectonic plates drag more carbon into Earth's interior than previously thought. They found that the carbon drawn into Earth's interior at subduction zones—where tectonic plates collide and dive into Earth's interior—tends to stay locked away at depth, rather than resurfacing in the form of volcanic emissions. Their findings, published in Nature Communications, suggest that only about a third of the carbon recycled beneath volcanic chains returns to the surface via recycling, in contrast to previous theories that what goes down mostly comes back up. One of the solutions to tackle climate change is to find ways to reduce the amount of CO2 in Earth's atmosphere. By studying how carbon behaves in the deep Earth, which houses the majority of our planet's carbon, scientists can better understand the entire lifecycle of carbon on Earth, and how it flows between the atmosphere, oceans and life at the surface. The best-understood parts of the carbon cycle are at or near Earth's surface, but deep carbon stores play a key role in maintaining the habitability of our planet by regulating atmospheric CO2 levels. "We currently have a relatively good understanding of the surface reservoirs of carbon and the fluxes between them, but know much less about Earth's interior carbon stores, which cycle carbon over millions of years," said lead author Stefan Farsang, who conducted the research while a Ph.D. student at Cambridge's Department of Earth Sciences. There are a number of ways for carbon to be released back to the atmosphere (as CO2) but there is only one path in which it can return to the Earth's interior: via plate subduction. Here, surface carbon, for instance in the form of seashells and micro-organisms which have locked atmospheric CO2 into their shells, is channeled into Earth's interior. Scientists had thought that much of this carbon was then returned to the atmosphere as CO2 via emissions from volcanoes. But the new study reveals that chemical reactions taking place in rocks swallowed up at subduction zones trap carbon and send it deeper into Earth's interior—stopping some of it coming back to Earth's surface. The team conducted a series of experiments at the European Synchrotron Radiation Facility, "The ESRF have world-leading facilities and the expertise that we needed to get our results," said co-author Simon Redfern, Dean of the College of Science at NTU Singapore, "The facility can measure very low concentrations of these metals at the high pressure and temperature conditions of interest to us." To replicate the high pressures and temperatures of subductions zones, they used a heated 'diamond anvil," in which extreme pressures are achieved by pressing two tiny diamond anvils against the sample. The work supports growing evidence that carbonate rocks, which have the same chemical makeup as chalk, become less calcium-rich and more magnesium-rich when channeled deeper into the mantle. This chemical transformation makes carbonate less soluble—meaning it doesn't get drawn into the fluids that supply volcanoes. Instead, the majority of the carbonate sinks deeper into the mantle where it may eventually become diamond. "There is still a lot of research to be done in this field," said Farsang. "In the future, we aim to refine our estimates by studying carbonate solubility in a wider temperature, pressure range and in several fluid compositions." The findings are also important for understanding the role of carbonate formation in our climate system more generally. "Our results show that these minerals are very stable and can certainly lock up CO2 from the atmosphere into solid mineral forms that could result in negative emissions," said Redfern. The team have been looking into the use of similar methods for carbon capture, which moves atmospheric CO2 into storage in rocks and the oceans. "These results will also help us understand better ways to lock carbon into the solid Earth, out of the atmosphere. If we can accelerate this process faster than nature handles it, it could prove a route to help solve the climate crisis," said Redfern. source: https://phys.org/news/2021-07-earth-interior-swallowing-carbon-thought.html
  14. Honeywell has unveiled a new rate sensor to help small satellites navigate increasingly crowded orbits above the Earth’s surface. The new micro-electro-mechanical system (MEMS)-based product provides low cost and power consumption in a smaller size than previous Honeywell offerings, while maintaining high performance levels. It is suitable for customers building smaller and lower-cost satellites, according to Honeywell. Honeywell’s HG4934 space rate sensor is roughly the same size and weight (145 grams) as a baseball. Compared to Honeywell’s previous rate sensors, it consumes only one-fifth the electric power, is more than 32 times lighter, and is 60 times smaller. It also is more tolerant of radiation, a key attribute in space. “With this new sensor, our customers can build smaller, lower cost satellites that are just as capable and reliable as their traditional predecessors, which will allow them to field new satellite technologies like 5G telecommunications or high-bandwidth global Internet,” said Mike Elias, vice president and general manager, Space, Honeywell Aerospace. “Furthermore, the number of satellites is only increasing, which leads to more crowded orbits. It’s critical that our customers have highly precise navigation solutions to help prevent accidents, which could knock functional satellites out of orbit.” A space rate sensor, also known as an inertial reference unit or IRU, is an inertial sensor composed of three gyroscopes that work together to sense rotation rates. They determine an aircraft or spacecraft’s change in rotational attitude over time and allow it to move from one location to another without using any external information. It can also serve as a backup solution to provide redundancy if other navigation systems fail. Celestial navigation options like star trackers are a popular method of obtaining pointing directions for satellites and spacecraft. This form of navigation uses angular measurements between objects in space (stars, planets, etc.) and the horizon to calculate location. However, sometimes these star trackers are blinded by the sun or affected by thruster gases. In this case, Honeywell’s HG4934 can act as a secondary method of attitude determination. source: https://aerospace.honeywell.com/us/en/learn/products/space/small-satellite-specific-bus-products/hg4934srs-3-axis-space-rate-sensor
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.



If you enjoy our contents, support us by Disable ads Blocker or add GIS-area to your ads blocker whitelist