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George H. Allen

@geoallen.bsky.social
523 followers 240 following 51 posts

Hydrologist and satellite enthusiast. Associate Professor at Virginia Tech

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George H. Allen @geoallen.bsky.social · 24/07/2026
🚨Job Alert!🚨 I'm recruiting a postdoc starting Fall '26 or Spr '27 focused on: (1) Satellite remote sensing of inland surface water (2) Hydrologic applications of geospatial foundation models, LSTMs, or other AI/ML approaches. If you're interested, DM me or fill out this form: lnkd.in/gf3fMmx8
The New River near Blacksburg, VA
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George H. Allen @geoallen.bsky.social · 13/07/2026
We will convene our long-running #AGU session this fall: Remote Sensing of Rivers, Lakes and Wetlands. Consider submitting an abstract! Invited presenters: Dongmei Feng (U of Cincinnati) and Lian Feng (Wuhan U) Conveners: George Allen, Huilin Gao, Jessica Fayne, Ted Langhorst, Anshul Yadav
AGU 2026 Flyer
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George H. Allen @geoallen.bsky.social · 13/07/2026
Q: How much do dams alter river temperatures in the US? A: Quite a lot, according to Landsat data Check out our new paper in Science Advances: Satellite observations reveal widespread alteration of river thermal regimes by US dams doi.org/10.1126/scia...
Fog forming above cold water downstream of the Cheoah Dam in western North Carolina. Photo Credit: George Allen
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Amanda Gay DelVecchia @agdelv.bsky.social · 10/07/2026
So grateful and excited to officially have NSF support to investigate how cryptic and/or chemosynthetic carbon contributes to stream productivity! Here's our upcoming work: amandadelvecchia.weebly.com/lab-news AND an amazing PhD student opportunity 😀 amandadelvecchia.weebly.com/join-the-lab...
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AGU Hydrology H3S @agu-h3s.bsky.social · 06/06/2026
A great figure can elevate your paper, increase scientific accessibility, and even become art. Are you an early career researcher in hydrology with a (published) figure that you are proud of? H3S wants to spotlight you! Submissions accepted here → docs.google.com/forms/d/e/1F...
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The Geological Society of America (GSA) @geosociety.bsky.social · 01/04/2026
A new study published in GSA Today is changing the way scientists answer that question—using data from NASA’s SWOT satellite to track how rivers erode, transport sediment, and reshape landscapes across Earth. Read the paper: geosociety.co/Stroud_et_al #NASA #RemoteSensing #Geomorphology
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Jennifer N. Victor @jenvictor.bsky.social · 16/03/2026
This is an incredible documentation of the systematic, intentional collapse of American health science, by Elizabeth Ginexi. open.substack.com/pub/elizabet...
open.substack.com
I Wrote Research Funding Announcements for NIH for 22 Years. This Year They’ve Published 14
How NIH went from 756 funding announcements to 14 in two years — and what it means for every disease that depends on federal research
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KinarNicholas.bsky.social @kinarnicholas.bsky.social · 13/03/2026
Hydrology Paper of the Day @geoallen.bsky.social on distinguishing between lakes and reservoirs by SWOT observations: estimating storage by the LakeFlow algorithm; statistical tests for differences; characterizing variability; and understanding reservoir inflows and outflows.
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George H. Allen @geoallen.bsky.social · 19/02/2026
Our new paper uses #SWOT_satellite data to differentiate between natural & managed lake dynamics across North America. We find that inflows & outflows of managed lakes are significantly more variable than natural lakes, revealing signatures of reservoir operations: doi.org/10.1088/1748...
Cross correlation results for lagging outflow discharge estimates at 779 lakes. (a) Map showing each lake’s lag time in
days at the highest Spearman correlation (ρ). (b) The percentage of natural lakes and reservoirs based on the lag time with the
highest ρ.
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George H. Allen @geoallen.bsky.social · 29/01/2026
New paper by Katie McQuillan leverages satellite radar to map lake evaporation at 25× finer resolution than operational surface analysis products, opening up applications from improved gauge placement to evaluating geoengineering strategies doi.org/10.1109/LGRS...
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George H. Allen @geoallen.bsky.social · 05/12/2025
New paper is featured on the cover of GSA Today 🥳 We show that the #SWOT satellites's radar observations are a valuable new source of data for studying river processes/ fluvial geomorphology. Led by Molly Stroud @mollystroud.bsky.social @vt-science.bsky.social Paper: doi.org/10.1130/GSAT...
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John Hammond @hydrohammond.bsky.social · 23/11/2025
Time to get your public comments in on the proposed Waters of the U.S. rule that would strip protections for countless wetlands and streams. Trout unlimited has a tool on their page that will automatically send your message to the EPA as well as your representatives: www.tu.org/conservation...
tu.org
Take Action - Trout Unlimited
It only takes a minute to stand up for clean water and healthy fisheries.
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George H. Allen @geoallen.bsky.social · 19/11/2025
Grad students in my group participate in the 2025 Flip the Fair science fair and research expo in Salem Virginia
communicatingscience.isce.vt.edu
Flip the Fair 2025 Inspired Young Minds and Future Scientists from Roanoke City Public Schools
Nov. 5, 2025. Flip the Fair celebrated its fourth year this fall, continuing the tradition that began in 2022. This event invited fifth grade students from Roanoke City Public Schools to step into the...
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George H. Allen @geoallen.bsky.social · 10/11/2025
This weekend my research group volunteered at the Claytor Lake Mussel Salvage event near Blacksburg, VA. We surveyed and relocated hundreds of native mussels during the scheduled biennial lake drawdown. #UtProsim @vtgeosciences.bsky.social @vt-science.bsky.social
Global Rivers Group members: Emily Ellis, Steve Yoon, Yohtaro Kobayashi, David Go, Hana Thurman, and George Allen show off their mussels at the Claytor Lake Mussel Salvage eventYohtaro Kobayashi and Hana Thurman search for native mussels as David Go and Emily Ellis clean up trash in the background
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Mirela G. Tulbure, PhD @mirelagtulbure.bsky.social · 03/11/2025
Join the Global Flood Partnership (GFP) 2025 Fall Webinar Series! On November 19, 2025 (16:00 CET), we bring you three expert talks on how Earth-Observation data is transforming flood mapping, risk assessment, and resilience strategies. Register here: lnkd.in/gjYX3GV8 See also: lnkd.in/gRQFuk_J
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George H. Allen @geoallen.bsky.social · 17/10/2025
Another SWOT Science Team Meeting for the books!
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Marc Veldhoen @marcveld.bsky.social · 06/10/2025
27 things we wish we’d known when we started our PhDs Nature’s survey of PhD candidates reveals hard-won wisdom on choosing supervisors, managing mental health and surviving academic culture.
nature.com
27 things we wish we’d known when we started our PhDs
Nature - Nature’s survey of PhD candidates reveals hard-won wisdom on choosing supervisors, managing mental health and surviving academic culture.
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AGU (American Geophysical Union) @agu.org · 06/10/2025
We’re on Capitol Hill with 225 Earth & space scientists — including @aas.org and @planetarysociety.bsky.social — urging Congress to reopen the government and protect NASA science. 🚀🌍 Join us: buff.ly/a3YuGgY #ScienceIsEssential #AGU
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George H. Allen @geoallen.bsky.social · 25/09/2025
First NISAR L-band images released! They look great! www.jpl.nasa.gov/news/nasa-is...
jpl.nasa.gov
NASA-ISRO Satellite Sends First Radar Images of Earth’s Surface
Preliminary images from the most powerful Earth radar satellite ever launched offer a tantalizing glimpse of the science the mission will be able to deliver.
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Albert Ruhí @albertruhi.bsky.social · 23/09/2025
Looking for a postdoc, and interested in river-coastal linkages, #remote sensing, and time series analysis? Come work with us @natureatcal.bsky.social on an exciting project led by @rachelspatial.bsky.social! CC @sfs-src.bsky.social @aslo.org @cerfscience.bsky.social ‪‪@caseagrant.bsky.social‬
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Audrey Thellman @audreythellman.bsky.social · 14/07/2025
Hello freshwater friends! I’m starting a lab(!!) and recruiting 2 students to start Fall 2026 and a lab/field assistant to start this Fall 2025! Research topic is broad: rivers 🛶, ice/snow ❄️, nutrients 🍂, algae 🌱see below for more info Please pass this along to any interested folks :)
Ad for 2 graduate student positions and and 1 lab and field assistant position at UCSB. More info go to audreythellman.weebly.com
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George H. Allen @geoallen.bsky.social · 11/07/2025
Flood waves like those that devastated Texas last week can be seen by the NASA #SWOT satellite. Another reason to support #NASA Earth Science
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AGU Hydrology H3S @agu-h3s.bsky.social · 08/07/2025
AGU H3S invites you to submit an abstract to our session at #AGU25 Thinking Outside the Box Plot: Communicating Science Beyond the Paper! The session explores creative ways to communicate research. Conveners: @adischner.bsky.social @acarneiromar.bsky.social @gescilam.bsky.social Cee Nell Emily Ellis
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AGU Hydrology H3S @agu-h3s.bsky.social · 08/07/2025
AGU H3S invites you to contribute to our session at #AGU25 Hydrology Student, Postdoc, and Early Career Flash Talks! This session highlights research performed by fellow Early Career Researchers within the field of Hydrology. Conveners: Matthew Preisser and Kathryn Moore
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George H. Allen @geoallen.bsky.social · 19/06/2025
🚨New paper🚨 shows a remarkably clean relationship between river width and stream order across the US 𝑇ℎ𝑒 𝑊𝑖𝑑𝑡ℎ𝑠 𝑜𝑓 𝑅𝑖𝑣𝑒𝑟𝑠 𝑎𝑛𝑑 𝑆𝑡𝑟𝑒𝑎𝑚𝑠 𝐴𝑐𝑟𝑜𝑠𝑠 𝑆𝑝𝑎𝑡𝑖𝑎𝑙 𝑆𝑐𝑎𝑙𝑒𝑠... 🔗 doi.org/10.1029/2025... #hydrology #geomorphology #rivers #RemoteSensing
River widths of each stream order exhibit predictable log-normal distributions.
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George H. Allen @geoallen.bsky.social · 27/05/2025
Hana (grad student in my group) will be doing a research internship at JPL this summer. Here she is on her first day on the job. Good luck, Hana!! 🚀🚀🚀
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George H. Allen @geoallen.bsky.social · 21/05/2025
NASA news article on our recent study on the #SWOT satellite's ability to capture hydrologic flow waves in rivers Link to paper: doi.org/10.1029/2024GL113875
nasa.gov
NASA-French Satellite Spots Large-Scale River Waves for First Time - NASA
In a first, researchers from NASA and Virginia Tech used satellite data to measure the height and speed of potentially hazardous flood waves traveling down
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Louise Slater @louiseslater.bsky.social · 16/05/2025
🌐 Introducing GRIT: the First Global Bifurcating River Network 🏞 developed by Michel Wortmann as part of the NERC Large Grant EvoFLOOD, in the Hydro-Climate Extremes group @oxfordgeography.bsky.social
Map of the GRIT global river network. Source: Wortmann et al. (2025), Water Resources Research.
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George H. Allen @geoallen.bsky.social · 19/05/2025
Hydrologists! Ever heard of a Spatial Hydrograph? Our new paper in @agu.org GRL shows that the SWOT satellite can capture spatial flow waves propagating down rivers—something previously only only observable at river gauges: doi.org/10.1029/2024... #SWOT #hydrology #RemoteSensing #EarthObservation
Example of how the Surface Water and Ocean Topography (SWOT) satellite's water surface elevation measurements can be used to record flow wave propagation over space and generate a “spatial hydrograph.”
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Prof Dan Parsons @bedforms.bsky.social · 16/05/2025
Delighted to see our @NERCscience @EvoFlood project research on changing flood hazard and risk profiled by @theAGU 💜 @lborouniversity eos.org/research-spo...
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Jacquelyn Gill @jacquelyngill.bsky.social · 14/05/2025
The American public is broadly supportive of maintaining federal science and medical research funding, and against punishing universities by taking their funding away, according to a new poll:
apnorc.org
Few support punitive funding cuts to colleges and universities - AP-NORC
Most of the public believes that colleges and universities make significant contributions to scientific and technological advancement and think their federal research funding should be maintained.
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Tamlin Pavelsky @globalhydro.bsky.social · 12/05/2025
Are water levels in wetlands important to you? @kica22.bsky.social's new paper in GRL shows that the SWOT satellite can measure water surface elevations in the Everglades with a mean absolute error of 6.7 cm. Check it out! agupubs.onlinelibrary.wiley.com/doi/10.1029/...
Scientific figuring with three panels. Left panel shows a map of the Everglades in Florida overlaid with data from the SWOT mission. It shows very detailed water level data throughout the everglades. The second panel, in the upper right, is a scatterplot showing in situ gauge water level against SWOT water level. It shows a mean absolute error of 6.7 cm, a correlation coefficient of 0.996, and a mean bias of 6.8 cm. The third figure, a scatterplot in the lower right, shows that by averaging 30 or more SWOT pixels, high accuracy is possible.
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George H. Allen @geoallen.bsky.social · 01/05/2025
Congrats to Luisana Rodriguez Sequeira, who successfully defended her Master's Thesis on satellite #remotesensing of #microplastics in rivers! I had the pleasure of co-advising with Dr. Austin Gray @austindoug13.bsky.social. She presented to a standing-room-only crowd—well done, Luisana!
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Tamlin Pavelsky @globalhydro.bsky.social · 19/03/2025
Do you work on lakes globally? Check out what is, to my mind, the most complete global database of lakes (~6M) and associated attributes, newly published in WRR. Also the basis for SWOT lake data. agupubs.onlinelibrary.wiley.com/doi/full/10....
Map of global lake distribution, colored by the number of SWOT overpasses per 21 day cycle. There are many lakes with a high number of SWOT overpasses at high northern latitudes, but there are also tens of thousands to more than a million lakes on every continent. Lakes are graphed by latitude and longitude on the edges of the figure.
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George H. Allen @geoallen.bsky.social · 08/04/2025
What a fun paper describing rivers in North and South America that flow into multiple drainage basins. agupubs.onlinelibrary.wiley.com/doi/10.1029/...
agupubs.onlinelibrary.wiley.com
Unusual Drainages of the Americas
We describe nine river bifurcations and bifurcation lakes in North and South America. They at first seem to defy the rules of hydrology These unusual water bodies exhibit bidirectional flow, unre...
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Brian Romans @clasticdetritus.bsky.social · 03/04/2025
Excited for the annual Virginia Tech Geoscience Student Research Symposium (GSRS) — a 2-day event w/ talks, poster sessions, the always-entertaining 'UpGoer Five' session, and more! It kicks off this morning and I'm looking forward to learning about all the amazing science our students are doing.
cover page of the 30th annual GSRS program
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George H. Allen @geoallen.bsky.social · 31/03/2025
Our new paper maps wind fields over lakes using radar backscatter from SWOT and Sentinel-1 satellites. This technique achieves a much higher spatial resolution than what is available from atmosphere reanalysis products: agupubs.onlinelibrary.wiley.com/doi/10.1029/...
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George H. Allen @geoallen.bsky.social · 07/03/2025
A graduate student takes a stream width measurement on Stroubles Creek, Virginia Tech.
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Laura Lautz @llautz.bsky.social · 19/02/2025
Yesterday was the darkest day of my professional life so far. Many of NSF’s best and brightest people fired indiscriminately. The terms of their firing cruel. My colleagues matter, they are valued and they make a difference. I have no words. www.npr.org/2025/02/18/n...
npr.org
National Science Foundation fires roughly 10% of its workforce
NSF fired 168 employees, leaving the agency less equipped to fund a wide range of scientific research.
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AGU (American Geophysical Union) @agu.org · 04/02/2025
We are alarmed by the Administration’s actions to freeze science funding and eliminate DEI efforts and climate change initiatives, which go against AGU’s mission and harms our members. We must unite to address these changes, beginning by hearing from you. Read more: buff.ly/4hm8r4e
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WATERSHED Investigations @watershed-i.bsky.social · 26/01/2025
New US administration ditches Biden's plan to limit levels of PFAS manufacturers can discharge into rivers from their waste pipes. Numerous studies have linked PFAS to cancers, liver, thyroid, kidney conditions, fertility issues & harm to fetal development 🧵 www.ewg.org/news-insight...
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Hilary McMillan @mcmillanhydro.bsky.social · 14/01/2025
Interested in headwater streams? Headwaters make up 77% of global river networks, but have fewer gauges, less accurate models and lesser protections than large rivers. See our review led by @goldenwater.bsky.social at www.nature.com/articles/s44...
nature.com
Advancing the science of headwater streamflow for global water protection - Nature Water
Despite their substantial contributions to watershed resilience, headwater streams are becoming increasingly imperilled. This Perspective summarizes the status of headwater streamflow information and ...
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Camille Minaudo @caminaudo.bsky.social · 07/01/2025
❗One week away before Abstract submission deadline for #EGU25. ➡️Consider session HS10.5 where we invite all contributions aiming at bridging limnology and hydrology together to better connect lakes and reservoirs to their catchments 💧🧪💻 meetingorganizer.copernicus.org/EGU25/sessio...
Advertising for special session HS10.5 to be held at EGU 2025, titled "Towards an integrated lake-catchment perspective".
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George H. Allen @geoallen.bsky.social · 31/12/2024
New paper by Dongmei Feng finds an interesting pattern in global streamflow trends through time: increasing streamflow in upstream river reaches and decreasing flow in downstream reaches: www.science.org/doi/full/10....
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George H. Allen @geoallen.bsky.social · 22/12/2024
See you when I’m 75!
forbes.com
18-Year Study Of 82,297 Adults Finds Cycle Commuting Halves Chance Of Early Death
Billionaires famously want to live longer. They should jump on bicycles, not spacecraft.
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George H. Allen @geoallen.bsky.social · 15/12/2024
Cool paper alert: Yu et al. used SWOT satellite observations of the ocean's surface height to create a global seafloor map at 8-km resolution: about twice the spatial resolution of previous global maps! science.org/doi/full/10....
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George H. Allen @geoallen.bsky.social · 11/12/2024
The Global Rivers Group is well represented this week at #AGU. Seven current members and three alums here in DC. #AGU24
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Gerard Rocher-Ros @grocherros.bsky.social · 08/12/2024
I am soon recruiting two PhDs and a postdoc, to work on carbon, methane, metabolism in arctic stream networks. Glad to chat potential opportunities during #AGU24 @agu.org ! There is also soon another postdoc position on oxygen responses to peatland restoration with @ryansponseller.bsky.social ⬇️
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George H. Allen @geoallen.bsky.social · 07/12/2024
Same thing is happening in the field of flood forecasting
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New York Times Opinion @nytopinion.nytimes.com · 06/12/2024
“There are just two major pacts governing nuclear weapons in the cosmos, both of which predate Neil Armstrong’s first steps on the moon,” W.J. Hennigan writes. Decades later, are they enough to protect against a new space Cold War? nyti.ms/4imfWsG
nyti.ms
Opinion | What One Russian Satellite Tells Us About the Future of Nuclear Warfare
No shockwave. No mushroom cloud. But a space nuke would change life on Earth forever.
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