Introduction
The Superior Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Science Crew (ST) organized a three-day workshop that came about September 9–11, 2024, on the Japan Area System’s (JSS) places of work in Tokyo, Japan. About 30 folks from Japan and the U.S. participated within the in-person assembly – see Picture 1.
U.S. contributors included representatives of two NASA facilities, Goddard Area Flight Heart (GSFC) and Jet Propulsion Laboratory (JPL); from the NASA Land Processes Distributed Lively Archive Heart (LPDAAC); from two universities, College of Arizona (UA) and College of Pittsburgh (UPitt); and from two non-public firms, Grace Consulting (GC) and Science Techniques and Functions, Inc. (SSAI). Japanese contributors included representatives from Japanese authorities companies, together with JSS, Geologic Survey of Japan (GSJ), Ministry of Economic system, Commerce and Trade (METI), Nationwide Institute for Environmental Research (NIES), Nationwide Institute of Superior Industrial Science and Expertise (AIST), and Distant Sensing Expertise Heart of Japan (RESTEC); in addition to from a number of universities, together with Ibaraki College (IU), Nagoya College (NU), College of Tokyo (UT), and College of Tsukuba (UTs).
The principle aims of the 53rd ASTER STM have been to:
- talk about impacts of the NASA-decreed 50% discount to the Terra mission’s funds for Fiscal Years 2024–2026 on ASTER (one in every of 5 devices flying on the Terra platform);
- reply to present and plan for future impacts on ASTER from the continuing efforts to preserve energy (scale back load) on the Terra platform;
- evaluate revised Terra spacecraft administration protocols from the Flight Operations Crew;
- obtain updates on knowledge acquisition standing, knowledge calibration and validation actions, and knowledge distribution plans and purposes utilizing ASTER observations; and
- talk about Terra and ASTER end-of-mission plans.
The rest of this text will summarize the highlights from the assembly. The report begins with a quick evaluate of the opening plenary session. The majority of the content material is devoted to summaries of the 4 working group periods. Because the identify implies, that is the place the majority of the work accomplished throughout a typical ASTER STM is completed. A quick evaluate of the closing plenary, which included abstract experiences from the chairpersons of all of the working teams, rounds out the abstract, adopted by some general concluding ideas – together with plans for the following assembly. Entry to full presentation experiences is password protected; these fascinated by having access to extra info ought to contact the creator straight.
Opening Plenary Session
Yasushi Yamaguchi [NU—Japan ASTER Science Team Leader] and Michael Abrams [JPL— U.S. ASTER Science Team Leader] welcomed contributors and reviewed the agenda for the opening plenary and the schedule for the remainder of the week’s working teams. Shinsuke Nakao [Geologic Survey of Japan—Director General] introduced a particular welcome and spoke of ASTER’s persevering with worth for geologic purposes.
Abrams introduced highlights of science outcomes primarily based on ASTER knowledge, reviewed the standing of the 2023 Senior Assessment, and mentioned the 50% discount of the Terra challenge (and JPL ASTER challenge) three-year funds. He reported that Terra passivation is scheduled for March 2027 and briefly described Terra’s energy standing.
Kurt Thome [GSFC—Terra Project Scientist] introduced on the standing of the Terra spacecraft – together with extra on its energy administration scenario in gentle of this 12 months’s photo voltaic shunt array failures. The ability points however, Terra stays largely wholesome after 24 plus years of operation.
Hitomi Inada [JSS] offered a standing report on the ASTER instrument. Inada defined that whereas most of the monitored elements (i.e., visible-near-infrared (VNIR) pointing motor) are past their authentic helpful life in orbit, the getting old {hardware} reveals no indicators of carrying out or lowering in efficiency. She confirmed that the temperature and present telemetry tendencies stay straight traces.
Cole Krehbiel [LPDAAC] introduced ASTER product distribution statistics. The ASTER Digital Elevation Mannequin continues to be essentially the most ordered product. As outlined by the ST on the final assembly, most ASTER knowledge merchandise can be created as bodily, archived information earlier than the top of the mission and positioned in a searchable/orderable archive that may be accessed via NASA’s Earthdata instrument. The ST reviewed the listing of merchandise and formally accepted it. Krehbiel stated that LPDAAC will begin producing these information in January 2025.
Koki Iwao [AIST] introduced product distribution statistics for his group. The biggest variety of customers of merchandise from Japan have been from the U.S. He stated that essentially the most requested product was the pseudo-neutral colour rendition.
Tetsushi Tachikawa [JSS] reviewed the standing of ASTER statement packages because the starting of the mission. He reported that all the world statement packages are functioning usually, buying knowledge as deliberate. Updates to the statement packages can be thought-about by future working teams. Tachikawa additionally added that the change of the orbit repeat – after Terra’s October 2022 exit from the Morning Constellation – has been accommodated within the ASTER scheduler.
Mike Abrams then introduced a report from Simon Hook [JPL], who was unable to attend the assembly, on the standing of the multispectral thermal infrared (TIR) bands on NASA’s ECOsystem Spaceborne Thermal Radiometer Experiment on Area Station (ECOSTRESS) mission. The TIR bands on ECOSTRESS are much like these on ASTER – however ECOSTRESS has completely different statement repeat cycles on account of being positioned on the Worldwide Area Station [Altitude: 408 km (254 mi); Inclination: 51.6°; Period: 90 min] versus being positioned on a polar-orbiting platform, similar to Terra/ASTER [Altitude: 705 km, (438 mi); Inclination: 98.5°; Period: 99 min, 16-day ground track]. Abrams additionally spoke about NASA’s future Floor Biology and Geology (SBG) examine, which is being carried out to give you ideas and in the end slim down and choose the design for the SBG mission that can be a part of the deliberate Earth System Observatory. SBG can be the following U.S. mission (after Terra/ASTER and Landsat) to make TIR observations.
Tsuneo Matsunaga [NIES] introduced the standing of Japan’s Greenhouse Gases Observing Satellite tv for pc (GOSAT) program. First made operational in 2009, GOSAT measures the focus of carbon dioxide (CO2) globally. The third satellite tv for pc within the collection, GOSAT-GW can be launched in 2025. It has each a large swath mode [90–911 km (~145–1465 mi)] and a slim swath mode [3–10 km (~5–16 mi)]. Matsunaga defined that the extensive swath permits for world, repeating protection whereas the slim swath allows larger spatial decision statement, helpful for observing level sources of greenhouse gases. He then reviewed the standing of the Hyperspectral Imager Suite (HISUI) hyperspectral scanner on the Worldwide Area Station. He confirmed examples the place HISUI knowledge are used to detect CO2 emissions from energy vegetation.
Functions Working Group
The purposes session offered a sampling of the big variety of purposes that make use of information from ASTER. A number of examples are highlighted beneath.
Michael Ramsey [UPitt] reported the present progress of the Pressing Request Protocol (URP). He defined that the protocol triggers ASTER expedited acquisitions utilizing thermal triggers from larger temporal sensors, such because the Average Decision Imaging Spectroradiometer (MODIS). Every month, between 40–50 scenes are triggered by way of URP. Ramsey stated that these acquisitions present excessive temporal and spatial decision observations of energetic (erupting) volcanoes – see Determine 1. E-mail notifications are routinely forwarded to greater than 40 observatories working at every of the volcanoes.
Mike Abrams introduced using ASTER’s 25-year historical past for geologic mapping and mineral exploration purposes. He defined how the primary printed papers appeared just a few years after launch and validated the distinctive mineralogical info contained within the ASTER knowledge. Over the next 20 years, a number of experiences from mineral exploration firms introduced the invention of gold, chromite, and lithium deposits – which have been discovered largely primarily based on evaluation of ASTER knowledge.
Ashley Davies [JPL] introduced an replace on the standing of the ASTER Volcano Archive (AVA), operated by JPL. He confirmed examples from the archive, which has over 1.4 million ASTER scenes from over 1542 energetic volcanoes which were acquired because the starting of the mission in 2000. Davies additionally demonstrated how customers can search the archive by volcano identify and obtain numerous ASTER merchandise, helpful for volcano monitoring. He indicated that future merchandise envisioned for AVA embody sulfur dioxide (SO2) focus maps and quantitative thermal detection and knowledge evaluation.
Calibration/Validation Working Group
This working group is liable for monitoring the radiometric and geometric efficiency of ASTER’s VNIR and TIR devices. Three deferent calibration and validation strategies are used together with: evaluation of onboard calibration lamps, comparability with blackbodies, and measurements of pseudo-invariant floor targets throughout discipline campaigns. The Degree-2 (L2) software program algorithms are being up to date for the ultimate, archival processing.
Bjorn Eng [JPL] reported that the latest model of the L2 algorithm for calibration and validation of ASTER VNIR and TIR knowledge has been delivered to the LPDAAC for ingest and testing. He defined that the brand new model of the software program consists of the potential to make use of Fashionable-Period Retrospective Evaluation for Analysis and Functions, Model 2 (MERRA-2) knowledge, which permits customers to create atmospheric profiles for temperature, stress, water vapor, and ozone. MERRA-2 is an enchancment – each spatially and temporally – over the Nationwide Facilities for Environmental Prediction’s (NCEP) International Information Assimilation System (GDAS) that’s used within the authentic MERRA. Eng requested for volunteers who can be keen to check L2 merchandise created with the brand new model of the software program to these created utilizing the previous model, to confirm the accuracy of the brand new software program earlier than it’s used for the archival processing.
Cole Krehbiel reported on the evaluation of geometric efficiency of the L1 processing software program, which was up to date to the brand new Landsat floor management level library and an improved world digital elevation mannequin. He confirmed that the brand new merchandise present minor enchancment over the previous. Krehbiel defined that the revised software program can be used for the archival processing.
Satoshi Tsuchida [GSJ] introduced the outcomes from calibration discipline campaigns carried out at Railroad Valley, NV in August 2023 and 2024. They present that ASTER VNIR Bands 1, 2, 3N, and 3B haven’t deviated from the present calibration curves. Every of the bands continues to point out no degradation in efficiency, indicating that the present radiometric calibration desk doesn’t want updating.
Satoru Yamamoto [GSJ] introduced updates to the calibration tendencies of the onboard VNIR lamps. A number of analyses of the calibration lamps confirmed no vital change in all the info tendencies. The signal-to-noise ratios are nonetheless larger than the requirement of 140, which signifies that retrieval of floor reflectance to lower than 1% accuracy is feasible.
Hideyuki Tonooka [IU] introduced the outcomes of 5 current TIR discipline calibration campaigns: two in Japan and three within the U.S. He confirmed some preliminary outcomes from two campaigns carried out at Lake Kasumigaura, Japan. The information point out that the distinction between lake temperatures measured by ASTER and people measured in situ have been lower than 0.8 Okay – which is inside the required specs. Tonooka additionally reported that the three September 2024 discipline campaigns in Nevada and Utah went nicely. Nevertheless, these three occasions have been held only a week previous to the ASTER STM, so outcomes aren’t but accessible. .
Mike Abrams introduced a report on behalf of Simon Hook, on TIR validation utilizing automated websites at Lake Tahoe, NV, and Salton Sea, CA. These two websites have been used since 2000 to watch ASTER’s TIR efficiency. Measurements from a number of automated buoys are recorded and telemetered each few seconds and in comparison with every of ASTER’s 5 TIR bands. After atmospheric corrections and changes for ASTER’s TIR detector responses are utilized, the calculated radiance values from ASTER have been in comparison with the in situ observations. Abrams famous that – as has been the case in earlier years – all of the 2024 measurements present glorious settlement – see Determine 2.
Mehran Yarahmadi [SSAI] outcomes (printed in a 2024 paper in Distant Sensing on which Yarahmadi was lead creator) from an intercomparison of ASTER’s VNIR bands versus comparable knowledge from the Operational Land Imager (OLI) on Landsat-8 and OLI-2 on Landsat–9 utilizing the Radiometric Calibration Community (RadCalNet) knowledge from Railroad Valley, NV. Researchers discovered 100 matchups between the 2 devices that occurred between 2013 and 2023. The RadCalNet offered correct in situ measurements of floor reflectance. The staff in contrast Landsat and ASTER floor radiation measurements utilizing radiative switch software program and measured atmospheric situations. As well as, they in contrast the ratios for each OLI and ASTER with in situ values, which offered quantitative analysis of the radiometric efficiency of each devices – see Determine 3.
Temperature-Emissivity Working Group
This group focuses on ASTER’s kinetic temperature and emissivity (T–E) merchandise, in addition to utility of those merchandise and evaluate of the nighttime TIR world mapping program standing.
Mike Ramsey introduced TIR spectral retrievals of volcanic emissions from the brand new 12-channel Miniature Multispectral Thermal Digicam (MMT-gasCAM) instrument, with comparisons to ASTER TIR. He defined that the challenge pairs a business TIR microbolometer digicam with a customized filter wheel meeting. Ramsey stated that the brand new instrument improves on the six-channel instrument, beforehand operated within the discipline each on the bottom and from a helicopter. The primary assessments have been carried out in Italy in June 2024 – see Picture 2.
Hideyuki Tonooka mentioned the worldwide distribution of radiometer stations that JPL operates to calibrate and validate a number of spaceborne TIR scanners, together with ASTER. Within the U.S., stations are positioned on Lake Tahoe, which straddles the border of Nevada and Utah, and at Salton Sea, CA and Russell Ranch, CA. Internationally, there are stations at LeCrau Nature Protect, France and Venice, Italy. He additionally mentioned plans to put in JPL’s automated radiometer at Lake Kasumigaura, Japan no sooner than April 2025.
Tonooka additionally reviewed the standing of the present Thermal International Mapping acquisition program to amass cloud-free TIR nighttime pictures over many of the Earth’s land floor. He defined that this system is refreshed yearly, because the acquisition success begins to exhibit diminishing returns on account of remnant cloudy areas. The newest program began in Could 2024. Tonooka then reported on evaluation of the TIR acquisitions primarily based on cloud cowl. As of September 2024, 92% of the required world areas had been noticed not less than as soon as underneath clear sky.
Operations and Mission Planning Working Group
This working group oversees and critiques the acquisition packages executed by the ASTER scheduler. As a result of ASTER knowledge acquisitions should be scheduled every single day to accommodate ASTER’s common 8% obligation cycle, ST members developed an automated program to pick out 600–700 every day scenes from the greater than 3000 prospects within the request archive.
Tetsushi Tachikawa reviewed the standing of acquisition scheduling. Pressing observations obtain the very best precedence (by way of the URP mentioned in Michael Ramsey’s presentation) and may be scheduled near acquisition time. Roughly 70 scenes are programmed monthly – with over 95% acquisition success. In contrast, world mapping knowledge acquisitions obtain the bottom precedence and are used to fill within the scenes for the every day quota. Tachikawa defined that the ASTER staff’s purpose is to have the instrument purchase not less than one cloud-free picture for each place on Earth. On account of persistent cloud cowl, success is usually ~85% after a number of years, at which period this system is restarted. He reported that the following restart is deliberate for October 2024. He defined that the thermal group submits areal necessities to amass world nighttime protection with the thermal bands. The working group’s suggestion was to proceed the scheduling as deliberate. Tachikawa subsequent gave quick updates on three different acquisition packages that concentrate on islands, volcanoes, glaciers, and cloudy areas respectively. The worldwide volcano picture acquisition program will proceed with no change to the statement parameters. Acquisition of pictures of islands and over cloudy areas can even proceed in present kind. The worldwide glacier acquisition program can be modified to alter the VNIR achieve settings to optimize pictures over snow and ice.
Tachikawa additionally mentioned ASTER instrument operations in response to the Terra Load Shedding Plan. The working group agreed on the next order of choice: no change to the present operation; placing the VNIR instrument into secure mode and working solely the TIR instrument, placing ASTER into secure mode, and placing ASTER into survival mode.
Closing Plenary Session
Every chairperson summarized the shows, discussions, and suggestions that occurred throughout the working group session they chaired. The general consensus arising from these discussions was that the ASTER instrument is working usually – with no indications of any element failures. The ST is making ready to soak up the influence of the 50% funds discount on the Flight Operation Crew at GSFC in addition to they will. The principle influence, to this point, has been a small enhance in misplaced knowledge (1–2%) – due to the absence of operators to aim fast restoration. The ST additionally permitted plans for ASTER’s contribution to the Terra energy mitigation plan and the advice has been forwarded to the Terra Challenge Scientist and the Flight Operations Crew.
Conclusion
The 53rd ASTER STM efficiently lined all the essential points launched throughout the Opening Plenary Session. The ST labored on formulating priorities for discount of ASTER instrument operations in response to Terra energy reductions. Throughout working group periods contributors acquired updates on a wide range of subjects: e.g., instrument scheduling, instrument efficiency, archiving plans, and new purposes.
The organizers introduced that the 54th ASTER STM can be held in Spring 2025 on the similar venue in Tokyo. Watch the ASTER web site for particulars on particular dates.
Acknowledgments Work by the lead creator of this text was carried out at NASA/Jet Propulsion Laboratory, California Institute of Expertise, underneath a contract with the Nationwide Aeronautics and Area Administration.
Michael Abrams
NASA/Jet Propulsion Laboratory/California Institute of Expertise
mjabrams@jpl.nasa.gov
Yasushi Yamaguchi
Nagoya College/Japan Science and Expertise Company
yasushi@nagoya-u.jp
