b'Environmental geophysics Environmental geophysicssure that most of you know that AustraliaGSNSS/GPS positions https://www.abc.is moving generally northeast at a ratenet.au/news/science/2023-05-25/tonga-of about 7 cm per year. See, for example,volcano-eruption-super-plasma-bubble-The Conversation from February 6, 2017gps-atmosphere/102377782(https://theconversation.com/australia-on-the-move-how-gps-keeps-up-with-a- Following are two of the (related) rabbit continent-in-constant-motion-71883). Iholes that I fell into along the way. I am hadnt really thought about it, but whengoing to work my way through them you are moving north at that rate, thoseover the next few weeks/months (my of us who need to consistently return tosuccess with both so far is not great) exactly the same location on continentalbut am sure that others in the ASEG Australia need that kind of correction. community have experience with these, and I would not mind being enlightened Mike Hatchas to their usefulness.Associate Editor Interestingly, parts of the atmospheric for Environmental geophysicsphysics community use the raw dataRabbit hole #1: The \x1drst is a Geoscience michael.hatch@adelaide.edu.au available from the GNSS satellites andAustralia (GA) open-sourced code called receivers to estimate total electronGINAN, that you can run to improve the density/count (TEC) in the ionospherepositional accuracy from a GPS/GNSS along the path of the GNSS signal.device to (possibly) better than a decimeter Weird and wonderful These densities change dramatically(at no cost) (https://www.ga.gov.au/Welcome readers to this issues column onas a transient ionospheric disturbancescienti\x1dc-topics/positioning-navigation/geophysics applied to the environment.(TID) passes through the atmospherepositioning-australia/about-the-program/For this issue, my intention was to write(speci\x1dcally the ionosphere). One ofanalysis-centre-software). I downloaded it, about an interesting intellectual the mechanisms that cause TIDs arebut still (at the time of writing) need to test experience that occurred recently, and thatinteractions between neutral particlesthe program. For the real-time corrections, is related to environmental geophysicsin the atmosphere with plasma in theit requires (at the minimum) that you be at most only tangentially. Unfortunatelyionospherethese interactions mayable to output raw GNSS data to a laptop (interestingly?) I fell down a few rabbitultimately be pushed by large explosiveand that you have an internet connection. holes along the way, two of which I willforces in the lower atmosphere. TheseSounds simple but it feels as if the report on here as well. explosive forces include events like rocketlearning curve might be steep and require launches, and importantly, volcanicmore time than I have at the moment. Also, So, my original theme for this articleeruptions. As reported in Lin etal. (2022),I am somewhat expecting to \x1dnd that it was going to be how interesting it isthe 15 January 2022 series of eruption ofneeds a geodetic quality GNSS receiver but when an instrument that is designed forthe Hunga-Tonga Volcano in the remoteI am not sure about that.one speci\x1dc task is used for somethingSouth Paci\x1dc Ocean east of Fiji (near unrelated and possibly never envisionedTonga) was one of these sorts of events.Rabbit hole #2: I also found an online when the instrument/setup was planned.These TIDs travel very quickly throughservice on the GA website (AUSPOS) that I am speci\x1dcally referring to the array ofthe atmosphere, on the order of 360 toapplies corrections to Rinex \x1dles, output Global Navigation Satellite System (GNSS)390 m/s (i.e. at approximately the samefrom geodetic quality, dual-frequency instruments that measure Australiasvelocity as the lower-atmospheric Lambgeodetic quality GNSS receivers collected relatively rapid travel to the north.atmospheric pressure wave directlyin static mode (https://www.ga.gov.au/Recently I attended the weekly groupassociated with the eruption), althoughscienti\x1dc-topics/positioning-navigation/meeting of atmospheric physicists atthere are other similar events listed in thegeodesy/auspos). Unfortunately, it wont the University of Adelaide (I am part ofLin paper with much higher velocities.correct the Rinex output from my handheld the group as I have some expertise inUltimately (besides scienti\x1dc curiosity), theGPS (among other things I dont receive measuring greenhouse gases using thingsgoal is to see if GNSS receivers recordingboth frequencies). Too badwouldnt it be like eddy covariance towersits true,TIDs are able to provide early warninggreat to get 1 decimeter quality positional some of us just like to measure things) andinformation about remote volcanicinformation from a handheld GPS?they started discussing a paper that oneeruptions, and possible associated of the participants had read that perkedtsunamis There is much more to thisReferencemy interest (Lin etal., 2022) and some ofstory than I report here and there are also a which I understood. Apparently, there is anumber of articles on the subject that canLin, J -T., Rajesh, P. K., Lin, C. C. H., large network of GNSS receivers locatedbe found by searching the web for termsChou, M-Y., Liu J-Y., Yue, J., Hsiao, all around Australia and New Zealandlike TID GNSS, and looking through someT-Y., Tsai, H-F., Chao, H-M., Kung, (~600), Japan (~1300) and Taiwan (~140),of the references in the Lin etal. (2022)M-M., 2022. Rapid conjugate with quite a few scattered on oceanpaper. I found the whole subject quiteappearance of the giant islands in between, especially to the northinteresting and certainly a good exampleionospheric lamb wave signatures of Australia. The Australian network isof scientists getting information fromin the Northern Hemisphere after administered by Geoscience Australia,unexpected sources. Since I wrote thisHunga-Tonga Volcano eruptions, and is used at least partially to measurepiece the ABC has reported on an article inGeophysical Research Letters, 49, the relative tectonic-plate motion in thisthe journal Space Weather that discussese2022GL098222. https://doi.particularly active part of the world. Imthe impact of the Tongan eruption onorg/10.1029/2022GL09822227 PREVIEW JUNE 2023'