Tag: climate change

TCarta to map seafloor around remote Pacific island nation

TCarta Marine, a global provider of geospatial products and services, has been contracted by the United Kingdom Hydrographic Office (UKHO) to provide a baseline dataset of water depths and seafloor classification around the Republic of Kiribati.

Located in the Pacific Ocean, the island nation is threatened by rising sea levels.

“Most of Kiribati’s islands average less than two meters above sea level at present and the country’s 110,000 inhabitants are among the most vulnerable to the effects of sea level rise and the world’s first potential climate change refugees,” said Kyle Goodrich, TCarta president.

“We expect to map 5,000 square kilometers in total. Our seafloor maps will be used with other geospatial information by the UKHO to recommend policies that will assist the Kiribati in planning for and responding to this situation,” Goodrich said.

TCarta won the open bid for supply of Satellite Derived Bathymetry (SDB) to the UKHO to extract water depth measurements and seafloor classifications, including habitat types, from multispectral satellite imagery.

In this project, TCarta is processing eight-band DigitalGlobe WorldView-2 and -3 data predominantly, as well as four-band WorldView-4 and GeoEye-1 data to measure depths down to 30 meters at a resolution of two meters.

“The Kiribati project highlights the efficiency and cost effectiveness of SDB technology in a geographic area too remote and enormous for traditional marine or airborne survey methods,” Goodrich said.

The Kiribati nation is comprised of 33 atoll islands and multiple reefs spread over an area of the Pacific Ocean nearly the size of the Continental U.S. Multiple new reefs have been discovered by TCarta using this satellite derived approach at the start of this project.

The islands and surrounding environs have not been mapped in their entirety since the late 1800s. Acquiring bathymetric data and habitat classifications using traditional ship-borne sonar or airborne lidar are prohibitively expensive, logistically challenging and come at far higher cost and timeframe than a satellite-based solution.

“We began tasking the DigitalGlobe satellites to capture images in December and will deliver the final products to the UKHO in early March,” said Goodrich, “DigitalGlobe has been a tremendous partner in helping TCarta meet the project deadlines and challenging open ocean conditions with repeat tasking of imagery, collecting more than 300 images in support of the project, despite the loss of WorldView 4.”

TCarta has developed advanced bathymetric measurement technologies using satellite data. Funded by the National Science Foundation SBIR Phase I grant and known as Project Trident, this new technology is being deployed in the Kiribati project to remotely validate the bathymetry results.

February 27, 2019
ESA’s Pioneer mission sends GNSS-RO nanosatellites into orbit

News from the European Space Agency (ESA)

Two tiny GNSS-RO nanosatellites now circle the Earth, ready for action. The first European Pioneer mission lifted off Nov. 29 from Sriharikota, India, to put the satellites into orbit.

One of Spire’s Satellite Manufacturing Technicians (Tomasz Chanusiak) tests the Radio Frequency capabilities of a LEMUR2 nanosatellite in Spire’s cleanroom in Glasgow, Scotland. (Photo: ESA)

The shoebox-sized satellites were launched at 04:27 GMT into low Earth orbit by the Indian Space Research Organisation’s PLSV launcher, and opened their first communication windows with their owner, Spire Global, less than an hour after they separated from the rocket.

Both satellites were developed under ESA’s ARTES Pioneer programme, and will aim to prove the value of using nanosats for space-based GNSS Radio Occultation (GNSS-RO).

GNSS-RO. GNSS-RO is the process of using satellites to measure how GNSS signals are refracted by the Earth’s atmosphere. Experts can use these measurements to glean temperature, pressure and humidity information for weather forecasting and climate change monitoring.

In contrast, weather data gathered by weather balloons and aircraft can only reach certain altitudes, leaving the higher atmospheric layers untouched.

Satellites have no such restrictions. They can gather massive amounts of this data from the ground up to the mesosphere as they fly over the Earth. This is usually done by large satellites. Spire’s nanosatellites weigh just 5 kg each, and were assembled and tested entirely by Spire in under three months, at their headquarters in Glasgow, Scotland.

Named “Space as a Service,” the Spire Pioneer mission intends to prove that nanosat GNSS-RO is a commercially viable alternative to traditional methods.

Two nanosatellites built by Spire Global were launched into low Earth orbit Nov. 29. (Photo: ISRO)

The two tiny satellites will collect and distribute GNSS-RO data during their commissioning phase, after which they will go into full commercial data production mode, gathering weather information for meteorological institutions, maritime and aviation customers on demand.

ESA’s Pioneer initiative partners with companies like Spire to help them provide this kind of in-orbit demonstration and validation for third parties.

“We saw a gap in the market for what we call space mission providers: companies that offer all aspects of a space mission to validate a new technology or service for the benefit of others,” said ESA Pioneer Programme Manager Khalil Kably. “ESA is always looking to champion innovation in the space industry, and the idea of Pioneer is that these space mission providers can help this by being a one-stop shop for in-orbit demonstration and therefore reduce the barriers and complexity that can stifle new ideas.”

“Spire has been focused on developing unique data sources with high frequency updates for the entire Earth and has over 60 LEMUR-2 class satellites deployed in space complimented with a global ground station network,” Spire Global CEO Peter Platzer said. “Under Pioneer, we can offer our extensive experience in manufacturing and managing small spacecraft like these to those who cannot afford to waste money and time doing it themselves. This work with ESA helps further support the global development of commercial aerospace’s potential to make space access universal.”

“These incredibly clever shoebox-sized satellites built in Glasgow could slash the complexity and cost of access to space, presenting an exciting opportunity for the UK to thrive in the commercial space age,” UK Space Agency Chief Executive Graham Turnock said. “Through our £4m development funding, the government’s Industrial Strategy and by working closely with our international partners, we are helping UK businesses transform their ideas into commercial realities, resulting in jobs, growth and innovation.”

December 3, 2018
GPS reveals Antarctic bedrock rising

The entirety of West Antarctica contains enough ice that, if it were to melt, would cause oceans to rise 10 feet. While the West Antarctic ice sheet is at risk of collapse, GPS data suggests this crisis could be averted because the bedrock supporting it is rising.

Using GPS, an international team of researchers found that the viscosity of the mantle under the West Antarctic Ice Sheet is much lower than expected, with the crust rebounding faster than expected, possibly stabilizing against catastrophic collapse. According to the study, in 100 years, the uplift rates at the GPS sites will be 2.5 to 3.5 times more rapid than currently observed.

Backer Islands GPS station: The small mushroom-shaped GPS antenna is supported by the nearby equipment with solar panels. (Photo: David Saddler via Colorado State University)

Participating researchers led by scientists at the Ohio State University installed a series of GPS stations on rock outcrops around the region to measure the Earth’s rise in response to thinning ice. Measurements showed that the bedrock uplift rates near the coast of West Antarctica were as high as 1.6 inches per year, one of the fastest rates ever recorded in glacial areas.

“This very rapid uplift may slow the runaway wasting and eventual collapse of the ice sheet,” said Rick Aster, a co-author of the study from Colorado State University. Nevertheless, Aster told the UK’s Independent, “To keep global sea levels from rising more than a few feet during this century and beyond, we must still limit greenhouse gas concentrations in the atmosphere, which can only occur through international cooperation and innovation.”

The team also included DTU Space. Study results were published in the journal Science.

November 26, 2018
Esri’s Africa GeoPortal to help with urgent development challenges

Esri has launched the Africa GeoPortal, a comprehensive cloud-based platform that provides rich content and solutions from Esri and its partners.

The geoportal provides access to Esri’s ArcGIS Online service as well as geographic data and imagery for Africa.

The African Union, African Development Bank, other international agencies, nongovernmental organizations (NGO), academia, businesses and national government funds will be able to use the geoportal to address the most urgent development challenges — from economic development and climate adaptation to conservation and health care.

“Access to this Africa GeoPortal powered by the ArcGIS platform will provide my colleagues at the iLab, and others in the network of African Technology Hubs (AfriLabs), with the information and analytical capabilities that we need to make the most effective development interventions for our citizens and communities,” said Luther Jeke, Manager of iCampus at iLab Liberia.

The complimentary software-as-a-service technology is offered to all who are supporting African nations for positive economic, social and environmental outcomes — African citizens, NGOs, and international development agencies alike.

The geoportal offers access to spatial analytics capabilities and authoritative content for charting compelling, educational, informational, entertaining and beautiful maps of Africa, Esri said.

“We are deeply committed to helping the people of Africa discover, explore, and understand the vast information available to them through the power of maps,” said Jack Dangermond, Esri founder and president. “Through this service, we hope to provide our users with the benefit of ongoing developments and investments at Esri so they can foster missions to the best of their abilities.”

To learn more about the Africa GeoPortal and Esri’s commitment to supporting the global community in the quest for sustainability through better mapping and location intelligence, visit go.esri.com/africa_geoportal.

Photo: Esri

May 11, 2018
Geologist uses lidar to monitor Greenland Glacier ice loss

A Riegl VZ-6000 laser scanner, operating at 1064 um wavelength, serves as the backbone of the ATLAS system.

Leigh Stearns, a geologist with the University of Kansas, is working with a Riegl VZ-6000 ultra long range terrestrial laser scanner, incorporated into an ATLAS (Autonomous Terrestrial Laser Scanning) system, to monitor rates of ice loss on the Helheim Glacier, a tidewater glacier undergoing large-scale changes due to global climate change.

“Lidar is an emerging technology for the earth sciences because it produces an incredibly detailed 3-D view of features,” said the KU researcher. “Repeat lidar scanning reveals small-scale changes with very high precision. These systems are now used to measure how bridges are sagging, how tectonic faults propagate and now how glaciers flow. The ATLAS systems are unique because they’re designed to scan the glacier terminus every six hours, year-round. That’s not a trivial task when there’s no sunlight in the winter, winds are high and it’s very cold.”

The VZ-6000 high speed, high-resolution terrestrial 3D laser scanner offers an extremely long measurement range of more than 6000 meters for topographic (static) applications. Due to its laser wavelength, it is exceptionally well suited for measuring snowy and icy terrain in glacier mapping and monitoring applications in mountainous regions.

Learn more about the project at the University of Kansas website.

November 30, 2017
Respect the facts: March for Science

Photo: Petr Kratochvil

In life, few things are certain. In family, love and friendship, fewer. Add more people — workplace, groups, associations, government, society, nations, war — and the complications multiply, the certainties become more scarce.

Some things, however, remain fixed, and true. We call them facts. They are not subject to denial or claims of fakery. They can sometimes be distorted, or their interpretation disputed, but at the end of the day they remain what they were at the beginning. Facts. True.

They do not require a majority to believe in them, nor even a powerful minority. They exist outside belief, heedless of the powers of persuasion, cajolery, hucksterism.

The facts do not always, to their detriment, speak for themselves. Reason does not always prevail. But the facts continue to exist, ruling the operations of the universe.

It has been said that journalism’s duty is to print the facts and raise hell (Chicago Times, 1861). I submit to you that it is a scientist’s duty — and an engineer is a scientist — to live and practice by the facts, to preserve the facts if necessary. To raise hell? That may be a matter of taste or personal style. But to see that the facts are known, shared, publicly available — that can be undertaken without uncomfortable or unpleasant hell-raising.

Guerrilla archiving and data rescues have mushroomed across the U.S., in response to fear that the U.S. government will remove facts it dislikes from its own websites. All-day hackathons are organized by volunteers; the events focus on downloading federal science data sets, particularly those related to climate change, from government websites and uploading them to a new site, datarefuge.org, an alternative source for data. They’re also feeding tens of thousands of government web pages into the Internet Archive, a nonprofit digital library with the mission of “universal access to all knowledge.” And of course someone has devised a custom-built app specifically for this purpose.

Climate-change data has a geospatial aspect, and much of it was collected with GPS equipment. Positioning coordinates lie at the heart of so much key information. So an attack on carefully assembled, scientifically overseen data can be interpreted as an attack on the validity of global positioning technology. Whether or not we take it personally, we should be wary of any attempt to deny or abolish any facts, anywhere.

We’ve seen this before, in other forms. The LightSquared episode in 2011–12 produced blatant denials of the physics of radio-frequency waveforms, for personal and institutional profit. We don’t yet know if this is happening again, whether government data has been erased or simply moved elsewhere.

Whether or wherever they appear or disappear, the facts continue to exist, and perhaps they deserve more respect than they’ve been getting.

MarchforScience.com, April 22.

March 14, 2017
Trump administration proposes slashing NOAA funding

Hurricane Fran at peak intensity on Sept.4, 1996. (Image: NOAA)

The Washington Post reported March 3 that the Trump administration proposes slashing the budget of the National Oceanic and Atmospheric Administration (NOAA) by 17 percent, cutting steeply into climate change research funding and satellite programs.

The Post cited a four-page budget memo it obtained. In the memo, NOAA’s Office of Oceanic and Atmospheric Research would lose $126 million, or 26 percent, of its funding, while NOAA’s satellite data division would lose $513 million, or 22 percent, of its funding.

The proposed cuts to NOAA would also eliminate funding for f smaller programs, including external research, coastal management, estuary reserves and “coastal resilience,” which seeks to bolster the ability of coastal areas to withstand major storms and rising seas.

NOAA is part of the Commerce Department, which would be hit by an overall 18 percent budget reduction from its current funding level.

March 4, 2017
New GNSS weather datasets available from TechDemoSat-1

GNSS-R Data collections. The measured reflection tracks are shown in yellow over the Globe. A sequence of Delay Doppler Maps from one track is shown below — the spread of each is related to the sea surface roughness and surface wind speed.

New weather datasets, which could prove highly valuable for weather forecasting and for longer term climate monitoring, have just been made available from the Space GNSS Receiver-Remote Sensing Instrument (SGR-ReSI) instrument on board TechDemoSat-1, a small technology demonstration satellite launched by Surrey Satellite Technology Ltd (SSTL) in 2014.

With support from the European Space Agency, SSTL and the National Oceanography Centre (NOC) are continuing to work on the data received from TechDemoSat-1 and have been steadily improving the calibration of the measurements and researching new techniques and applications.

New data, including delay Doppler maps and wind speed analysis over oceans, has been released on the MERRYBS website (Measurement of Earth Reflected Radio-navigation Signals By Satellite).

Looking to the future, the NASA CYGNSS mission due to launch later this year will fly eight satellites carrying SSTL’s SGR-ReSI instrument to measure the winds within cyclones, hurricanes and typhoons.

The SGR-ReSI instrument was developed by SSTL and is able to calculate TechDemoSat-1’s position and speed in much the same way as does a car-based SatNav, by measuring ranges and triangulating its position from high-altitude GNSS satellites orbiting 20,000 km above the satellite itself. The SGR-ReSI also carries a high-gain nadir (downward-pointing) antenna to utilize GNSS reflectometry, a technique where the GNSS signals scattered off the Earth’s surface are collected and measured.

A calm ocean will give a clean reflection, while a rough, wind-driven ocean will spread the signal out. SSTL’s partner, the National Oceanography Centre in Southampton, has developed an algorithm that calculates from the signals the ocean roughness and in turn estimates the wind speed at the surface of the ocean.

To validate the algorithm, NOC has compared the wind speed measurements from the SGR-ReSI against radar measurements from EUMETSAT’s MetOp satellite. These wind speed measurements are valuable for weather forecasting, and could also prove to be of significant benefit to the scientific community for climate monitoring.

The GNSS reflections off ice are much stronger than reflections off the ocean, and it has been possible to demonstrate from the results a new method for measuring the changing location of ice edges over time, and the potential for a new method of measuring ice height and thickness.

GPS reflections are not only collected by the SGR-ReSI over the ocean, but over land, where measurements to date show strong variations that could contain valuable geophysical information about the land surface. For instance, healthy vegetation will absorb more of the signal while damp soil can cause stronger reflections. Soil moisture is considered an essential parameter for climate monitoring, and is not currently measured with sufficient coverage over the globe.

TechDemoSat-1 was in part funded by Innovate UK and is jointly operated by SSTL in Guildford and by the Satellite Applications Catapult in Harwell.

SSTL received funding to support the development of the SGR-ReSI and ground processing from the UK CEOI, SEEDA, Innovate UK and the European Space Agency.

The below videos show processing and application of the SGR-ReSI data.

Video 1: This video shows in about 20 times real-time speed the motion of the TechDemoSat-1 satellite over an orbit, indicated by a white cross on the world map. The specular reflections targeted by the SGR-ReSI are shown by yellow spots, and the measurement tracks are shown in yellow.

The four Delay Doppler Map channels from measurement tracks are shown in yellow. The four Delay Doppler Map channels from the SGR-ReSI are shown at the top right.

The spreading horseshoe shape is caused by reflections being received away from the specular point, and a rougher ocean causes more spreading. When reflections are received from over land and over ice, there is much less spreading.

The red band on the map indicates the collection of “raw” unprocessed data, which takes a few minutes to transfer before the processed Delay Doppler Maps resume.

Video 2: This video shows reflections over the Northwest Passage, with and without ice.

November 29, 2016
Mapping the Arctic promotes international agreement
The Arctic SDI Board, — which includes mapping executives from Canada, Kingdom of Denmark, Finland, Iceland, Norway, Russia, Sweden and the U.S. — met June 14-16 in Anchorage, Alaska, to further develop a robust Arctic Spatial Data Infrastructure.

The Arctic SDI is a cooperation based on a Memorandum of Understanding signed by the eight National Mapping Agencies and is intended to ensure Arctic geospatial data is easier for users to access, validate and combine.

Erosion and climate change along Alaska’s Arctic Coast. (Photo: USGS)

A spatial data infrastructure (SDI) provides tools for data distributors to ensure geospatial data is easier for users to access, validate and combine with other data. Important data sets are produced and distributed by many stakeholders — in the public and private sector — and most of it can be geographically referenced.

“It’s important that scientists, resource managers, decision-makers and citizens can discover, access and use trusted data to conduct research, make informed decisions, and respond to emergencies in a changing Arctic,” said Kevin Gallagher, the USGS associate director for core science systems and current Arctic SDI Board chair. “The Arctic SDI initiative brings together geospatial experts and scientists in a voluntary cooperation between these country’s national mapping agencies in direct support of the priorities of the Arctic Council and other important stakeholders.”

The Arctic SDI cooperation has built a foundation on which important strategic work is being conducted by lead countries through several working groups in alignment with the five-year Arctic SDI Strategic Plan 2015-2020 adopted last year.

Polar bear mother and two cubs on the Beaufort Sea ice. (Photo: USGS)

The Arctic SDI Geoportal, launched in 2014, includes a continuously updated, harmonized pan-Arctic basemap using data delivered by the individual countries and national mapping agencies. Together they are working to increase the number of national authoritative datasets available through the Geoportal. The basemap, geoportal and access to data are continually being improved.

Additionally, an Open Geospatial Consortium (OGC) Arctic Spatial Data Pilot, sponsored by Natural Resources Canada and the USGS is underway to test interoperability of standards, increase the inventory of available Arctic data, and advance the understanding of best practices for distribution and sharing of data by showcasing the value of a standards based, data rich environment.

In 2009, the Arctic Council Senior Arctic Officials gave unanimous formal support to the Arctic SDI initiative and while the Arctic Council represents its primary stakeholder group, the Arctic SDI is aligned with the global, regional and national geodata context, including:
- The United Nations Committee of Experts on Global Geospatial Information Management (UN-GGIM),
- The Global Earth Observation System of Systems (GEOSS),
- The European Commission’s Infrastructure for Spatial Information in the European Community (INSPIRE)
- The U.S Federal Geographic Data Committee National Spatial Data Infrastructure (NSDI),
  and Canada’s Spatial Data Infrastructure (CGDI).
Additionally, the work adheres to Open Data principles, including facilitation of open and interoperable data based on OGC and ISO standards, specifications, architecture and software.

Arctic SDI Working Groups are continuing communication and outreach with stakeholders, especially the Arctic Council Working Groups, to advance understanding of data sharing and management techniques, and best practices to improve data access and availability. This work also includes development of communication materials, user guides and a manual.

Additionally, elevation experts from the national mapping agencies have been cooperating with the National Science Foundation and Polar Geospatial Center to provide data and expert reviews in support of a high quality Pan-Arctic Digital Elevation Model being developed in support of a U.S. Chairmanship Arctic Council Initiative.
August 23, 2016
Story map navigates cause and effects of climate change

Esri has released an interactive map illustrating the earth’s natural and human systems and how they have changed — and will change — over time. With the Atlas for a Changing Planet story map, scientists, policy makers, planners and activists can examine detailed spatial information that is critical for adapting to a warmer future.

“Mitigating the effects of climate change is a global, geographic challenge,” said Jack Dangermond, president of Esri. “Understanding how the earth’s systems interact and transform is an essential first step in measuring the threat of climate change and making informed decisions to reduce it.”

Atlas for a Changing Planet explores a sample of maps, imagery and data from Esri ArcGIS Online. The story map covers five themes: understanding natural systems, mapping human systems, mapping ocean impacts, predicting the future, and international cooperation.

Complex issues, processes, and concepts — such as biomass and ocean acidification — are clearly and succinctly explained with maps and multimedia, Esri said. For example, users visualize the density of carbon stored in living plants (biomass) with an explanation of how this information is key to estimating how land-use change affects the climate. Interactive maps illustrate which areas will be severely affected by rising sea levels, the changes in sea ice extents in the Arctic Ocean, and population growth in urban cities around the world.

The story map also models data from the National Center for Atmospheric Research (NCAR) in three scenarios. With this data, users navigate the story map to see projected changes in temperature and precipitation based on the level at which greenhouse gas emissions increase or decrease over time.

Esri created the story map in time for the Nov. 30 start of the United Nations 21st Conference of the Parties (COP21). World leaders are gathering at the annual meeting to negotiate an international agreement with the goal of keeping global warming’s increase below 2 degrees Celsius.

November 30, 2015
Esri Launches Climate and Human Health App Challenge

Esri has unveiled a Human Health and Climate Change App Challenge, calling on the worldwide GIS community to create apps that help communities visualize, understand and combat the health impacts of climate change. Esri will award three winners more than $15,000 in cash prizes or the equivalent in software. The deadline to enter is August 14.

The app challenge is part of Esri’s comprehensive effort in support of the White House Climate Data Initiative under President Obama’s Climate Action Plan. “Esri is committed to helping communities work smarter and more efficiently to become more livable and, as a result, more resilient to climate change,” said Esri president Jack Dangermond.

Participants are encouraged to create apps using Esri’s ArcGIS platform that provide decision-making support for health professionals and empower the public to take action. Apps should help private and public organizations combine open data to gain new insights into the impacts of climate change on health.

“Understanding the geography of climate change is critical to mitigating its health effects and creating a vibrant and sustainable future,” said Este Geraghty, Esri chief medical officer.

The app challenge is open to everyone — including developers, start-ups, governments, academics and nongovernmental organizations. Participants are encouraged to use the growing pool of open data and Esri apps, maps, services and APIs to develop their app.

Judges will select the top three apps to be highlighted at the Esri Health and Human Services GIS Conference in September. In addition to awarding prizes, Esri will feature the winning apps on its collaborative resource portal.

June 2, 2015
ESA Aims to Map Sea Surfaces with GNSS Radio Occultation

The International Space Station. (Photo: ESA)

Feature from the European Space Agency

A new concept that involves mounting an instrument on the International Space Station and taking advantage of signals from navigation satellites could provide measurements of sea-surface height and information about features related to ocean currents, benefiting science and ocean forecasting.

We have all seen the beautiful photographs of our planet taken by astronauts, but orbiting Earth 16 times a day just 400 km above, the Space Station also offers a platform from which to measure certain variables related to climate change.

So, in 2011 the European Space Agency (ESA) called for proposals to explore how the Space Station could be used to make scientifically valid observations of Earth. After reviewing and assessing numerous proposals, the result is to further develop the GEROS-ISS mission concept.

Jason Hatton, GEROS-ISS project coordinator, said, “The concept is still going through feasibility studies, but the aim is to launch the experiment towards the end of 2019. It would be carried to the Space Station on a cargo vehicle and installed on ESA’s Columbus space laboratory using a robotic arm, after which GEROS-ISS would run for at least a year.”

GEROS-ISS stands for GNSS reflectometry, radio occultation and scatterometry on board the ISS. GPS and Galileo satellites send a continual stream of microwave signals to Earth for navigation purposes, but these signals also bounce off the surface and back into space.

The idea is to install an instrument with an antenna on the Space Station that would capture signals directly from these satellites as well as signals that are reflected or scattered from Earth. This process could be used to calculate the height of the sea surface, and to measure waves — or “roughness” — that can then be used to work out the speed of surface winds.

Variations in sea-surface height (cm) obtained by merging multiple altimeter measurements. GEROS-ISS would be able to observe this variability so that maps covering latitudes 51° N to 51° S can be produced every four days. (Photo: ESA)

GEROS-ISS is primarily an experiment to demonstrate new ways of observing Earth. However, if taken beyond the testing phase this new approach would complement measurements from satellites carrying altimeters such as CryoSat and Sentinel-3, and satellites carrying wind scatterometers such as MetOp.

Importantly, it is the first concept to assess the potential of spaceborne GNSS reflectometry to determine and map ocean height at scales of 10–100 km or longer in less than four days. Current satellite altimeters, in comparison, offer global maps at scales of around 80 km, which are produced from multiple datasets every 10 days.

A system based on GEROS-ISS would, therefore, complement existing satellite systems, helping to map ocean variability at finer spatial and temporal scales over a range of seas in tropical and temperate regions. It would also refine our understanding of how well the concept would work for measuring the roughness of the ocean surface.

In this respect, the development of GEROS-ISS benefits from experience gained with the UK’s TechDemoSat-1, which also measures ocean-surface roughness using a similar technique. It is also hoped that NASA’s upcoming CYGNSS constellation of mini satellites will help pave the way for GEROS-ISS.

In addition, GEROS-ISS uses a technique called radio occultation whereby the antenna receives signals that are refracted as they pass through the atmosphere. This can be used to generate vertical profiles of atmospheric humidity, pressure and temperature, as does the GRAS instrument on the MetOp satellites, for example.

GEROS-ISS will be installed on the upper balcony of ESA’s Columbus space laboratory, which provides mechanical interface plates as well as power, command and data links to the ISS systems. (Photo: ESA, taken by ESA astronaut Luca Parmitano during his spacewalk on July 9, 2013. )

“It is very flexible, combining different mission concepts and applications in one: GNSS-reflectometry to determine sea-surface height, scatterometry to measure sea-surface roughness and radio occultation for atmospheric studies,” said Jens Wickert who leads the science team that proposed GEROS-ISS.

ESA engineer Manuel Martin-Neira noted, “The original concept actually goes back over 20 years and has matured considerably through numerous studies and campaigns, however, it has never been duly tested from space.”

“Being able to use the International Space Station in this way means that we can quickly validate innovative observing techniques without having to build an entire satellite, and we expect this to lead to new opportunities for science,” added Michael Kern, ESA’s GEROS-ISS mission scientist.

The GEROS-ISS feasibility studies are being carried out through ESA’s General Studies Programme.

Editor’s Note: GPS World discussed the use of GPS for radio occultation in its March 1994 Innovation column, “Monitoring the Earth’s Atmosphere with GPS,” by Rob Kursinski.

May 8, 2015