Andrew Dessler
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andrewdessler.com
Andrew Dessler
@andrewdessler.com
26K followers 1.3K following 9.3K posts
Prof of Atmospheric Sciences & climate scientist @ Texas A&M; AGU and AAAS Fellow; Native Texan; find out what I think at https://www.theclimatebrink.com/
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andrewdessler.com
As a metaphor of the world today, a little too on the nose.
November 7, 2025 at 1:19 AM
andrewdessler.com
understatement is a specialty of mine
Dessler said one of the scariest aspects of Melissa was the storm’s peak sustained winds of 185 mph (298 kph) winds. “That’s pretty rare to have a storm that strong. And I think that, to the extent that this is a harbinger of the future, it’s not good,” he said.
November 6, 2025 at 3:01 PM
andrewdessler.com
Andrew Gettelman giving the @tamuatmo.bsky.social Dept seminar. He talking about AI in an Earth System model. Lots of interesting results.
November 5, 2025 at 10:09 PM
andrewdessler.com
these people obviously have not read the Gates memo
press release that begins: People in Middle-Income Countries Say Climate Change is Affecting Their Community Majorities are willing to change the way they live and work to reduce effects of climate change WASHINGTON, D.C. (November 5, 2025) – Ahead of the United Nations Climate Change Conference in Belém, Brazil, this month, a new Pew Research Center survey of nine middle-income nations finds widespread concerns about climate change. Large majorities of adults in these countries say global climate change is affecting the area where they live, with a median of 74% saying it’s affecting their community at least somewhat.
November 5, 2025 at 7:25 PM
andrewdessler.com
More details of this heinous crime
On November 4, 2025, the Texas A&M University Police Department (UPD) received a report of a stolen golf cart. The victim reported that the golf cart was parked and secured in PA 102 on Saturday, November 1, 2025. They reported that it was stolen at approximately 2:20 PM. The golf cart is described as being maroon with an ATM sticker on the front hood, Texas A&M Athletics on the side, black handrails on the back, and a tan top.
November 5, 2025 at 5:00 AM
andrewdessler.com
College Station is crime-ridden hell hole. Thanks, Biden.

The perps better not relax: "This case remains under investigation."
Crime Alert – Theft of Motor Vehicle Campus crime alerts and timely warnings to the community comply with the federal Jeanne Clery Campus Safety Act (Clery Act). On November 4, 2025, the University Police Department was contacted by a staff member who had seen the recent crime alert. They provided information, which led to UPD successfully locating and recovering the golf cart in PA 20. The golf cart will be returned to the victim. This case remains under investigation.
November 5, 2025 at 3:22 AM
andrewdessler.com
Your dog looks like mine!
November 1, 2025 at 1:00 AM
andrewdessler.com
come on, autocorrect, what is this madness?
image of autocorrect trying to correct "data have" to "data has"
October 31, 2025 at 3:34 PM
andrewdessler.com
I asked my class of 20 undergrads if any of them knew who this guy was? ZERO did.

I was using his "known knowns, known unknowns, and unknown unknowns" to motivate a discussion or risk and uncertainty. It is a great line.
image of Donald Rumsfeld
October 30, 2025 at 6:49 PM
andrewdessler.com
Yes, Roger, it is personal: I was deeply offended by your accusation of plagiarism. Here's another dishonest claim, along with shots from the page you originally cut it from. This mischaracterized what I said in an attempt to make me look bad. I will never treat you as a respected colleague.
October 30, 2025 at 1:52 PM
andrewdessler.com
Better exposure on this photo
October 29, 2025 at 9:49 PM
andrewdessler.com
Great to have @andrewilwilliams.bsky.social give the ATMO @tamuatmo.bsky.social Dept. seminar. Fantastic talk!
October 29, 2025 at 9:30 PM
andrewdessler.com
Fall has finally arrived in College Station. About time.
October 29, 2025 at 4:03 PM
andrewdessler.com
October 28, 2025 at 1:26 AM
andrewdessler.com
Grokipedia basically copying Wikipedia articles, but with fewer sources and figures.
A Birkeland current (also known as field-aligned current, FAC) is a set of electrical currents that flow along geomagnetic field lines connecting the Earth's magnetosphere to the Earth's high latitude ionosphere. In the Earth's magnetosphere, the currents are driven by the solar wind and interplanetary magnetic field (IMF) and by bulk motions of plasma through the magnetosphere (convection indirectly driven by the interplanetary environment). The strength of the Birkeland currents changes with activity in the magnetosphere (e.g. during substorms). Small scale variations in the upward current sheets (downward flowing electrons) accelerate magnetospheric electrons which, when they reach the upper atmosphere, create the Auroras Borealis and Australis. A Birkeland current (also known as field-aligned current, FAC) is a set of electrical currents that flow along geomagnetic field lines connecting the Earth's magnetosphere to the Earth's high latitude ionosphere. In the Earth's magnetosphere, the currents are driven by the solar wind and interplanetary magnetic field (IMF) and by bulk motions of plasma through the magnetosphere (convection indirectly driven by the interplanetary environment). The strength of the Birkeland currents changes with activity in the magnetosphere (e.g. during substorms). Small scale variations in the upward current sheets (downward flowing electrons) accelerate magnetospheric electrons which, when they reach the upper atmosphere, create the Auroras Borealis and Australis.
October 28, 2025 at 1:26 AM
andrewdessler.com
Finally, we all have a paper like this
Hill, T. W. and A. J. Dessler, Plasma-sheet structure and the onset of magnetospheric substorms, Planet. Space Sci., 19, 1275-1288, 1971. This is an embarrassingly bad paper. Poor Tom – it was all my fault.
October 24, 2025 at 7:11 PM
andrewdessler.com
Dessler, A. J., Solar wind and interplanetary magnetic field, Rev. Geophys. 5, 1-41, 1967. Several firsts: (a) a thorough history, including noting the remarks of Kelvin that closed off research on a solar cause of geomagnetic storms until Chapman resurrected it. Although Chapman neglected Birkeland’s ideas (some he absorbed, but he gave Birkeland no credit). (b) The notion and the definition of “heliosphere” as where the solar-wind flows supersonically. This is where the word was coined. My heliosphere was surrounded by a “boundary layer”. If this terminology had been adopted, life would be a bit easier for present-day researchers because now they have to say which part of their heliosphere they are talking about. (c) The idea that the Sun is moving through the local interstellar medium toward an “apex”, and this motion distorts the heliosphere so it is pushed in on the apex side and extends further out on the antapex side, Fig. 14, p. 32. The boundary shell is predicted to form an extended tail in the antapex direction. And, (d) The boundary layer is unstable to the Rayleigh-Taylor instability, as suggested to me by Chandrasekhar.
October 24, 2025 at 7:11 PM
andrewdessler.com
Dessler, A. J., Length of magnetospheric tail, J. Geophys. Res., 69, 3913-3918, 1964. I argued that the Johnson teardrop model was unstable and that either hm radiation pressure or solar wind leaking into the magnetopause would cause the tail to be torn open. I did not appreciate magnetic merging without collisions, however, so the tail is too long. Ness used Fig 1 of this paper in his paper on the discovery of the magnetospheric tail. For “theory” he drew a dipole field. He cited my paper among a list of others interested in magnetospheres, but he gave no credit for my prediction. I had sent him a prepublication preprint. A modified version of this drawing is used on the Arcowski Medal (see also Fig. 4 of Dessler and Juday, 1965).
October 24, 2025 at 7:11 PM
andrewdessler.com
Cladis, J. B. and A. J. Dessler, X-rays from Van Allen belt electrons, J. Geophys. Res., 66, 343350, 1961. X-rays generated by electrons drifting into the South Atlantic Anomaly. Several balloon experiments verified these predictions. This paper was later rewritten by me and Tom and applied to Jupiter. I seemed to reapply the same ideas on different papers. Ahluwalia, H. S. and A. J. Dessler, Diurnal variation of cosmic radiation intensity produced by a solar wind, Planet. Space Sci., 9, 195-210, 1962. First explanation of CR diurnal variation that was on the right track. Contained two careless errors, one by me and one by Ahluwalia, corrected by Parker and Axford. so this paper got little credit.
October 24, 2025 at 7:11 PM
andrewdessler.com
A lot of the "inside baseball" of academics
Dessler, A. J. and E. H. Vestine, Maximum total energy of the Van Allen radiation belt, J. Geophys. Res., 65, 1069-1071, 1960. Showed that flux estimates by Van Allen and Winckler were too high by orders of magnitude. If they had been right, the ring current created would have been so strong that Carl Fredrick Gauss would have discovered that the Earth’s magnetic field had an external component. Van Allen later told me that this paper impressed him, although he studiously avoided mentioning it. Dessler, A. J., Discussion of letter by J. A. Van Allen, 'Further remarks on the absence of a very extended magnetospheric tail,' J. Geophys. Res., 71, 2408-2410, 1966. Historical note: Van Allen finally referenced some of my work, but not favorably.
October 24, 2025 at 7:11 PM
andrewdessler.com
This was an important paper
Dessler, A. J., Effect of magnetic anomaly on particle radiation trapped in geomagnetic field, J. Geophys. Rev., 64, 713-715, 1959. Prediction (discovery) of what is now called the South-Atlantic Anomaly.
October 24, 2025 at 7:11 PM
andrewdessler.com
Before he passed away, my father did an annotated bibliography of his papers. There are some pretty interesting things in it.
Dessler, A. J. and W. M. Fairbank, Amplitude dependence of the velocity of second sound, Phys. Rev., 104, 6-10, 1956. Based on my Ph.D. Thesis. An experiment showing Landau was right and Tisza was wrong. It has started to be cited (finally). Dessler, A. J., The propagation velocity of world-wide sudden commencements of magnetic storms, J. Geophys. Res., 63, 405-408, 1958. I believe this paper is the first serious attempt to use hm-theory in magnetospheric physics. Paper is, however flawed because it ignored Fermat’s principle of least time – see below, 1959 paper on the same subject. Dessler, A. J., Large amplitude hydromagnetic waves above the ionosphere, J. Geophys.Res., 63, 507-511, 1958; also Phys. Rev. Lett., 1, 68, 1958. Another first use of hm-theory, also wrong. There was a subsequent paper by me and Karplus (1960) doing it right and showing that there is, in general, little absorption of hm-wave energy in passing through the ionosphere. Dessler, A. J., W. B. Hanson, M. Hertzberg, D. D. McKibbin, and R. C. Wrigley, A new instrument for measuring atmospheric density and temperature at satellite altitudes, Jet Propul., 28, 837, 1958. W. B. Hanson built and used an instrument based on this idea.
October 24, 2025 at 7:11 PM
andrewdessler.com
someone needs to re-take the IT security learning module
from University email: IT Security and Password Reminders Our recent College IT Audit identified issues with the security of passwords on a significant number of Arts & Sciences computers. One observation was that some passwords were written on a piece of paper attached to monitors (e.g., a "post-it note"). This renders the computer inadequately secure. Remove any written passwords from public view and use a more secure method to remember passwords.
October 24, 2025 at 5:14 PM
andrewdessler.com
when giving a talk at Texas A&M, always start your talk with Howdy!
October 23, 2025 at 2:12 PM
andrewdessler.com
advertising fail: how to NOT sell a BMW to a College Station resident
October 21, 2025 at 5:31 PM