Elbridge Colby is also Catholic, and some of his religious beliefs factor into his policy preferences. Groton, Harvard BA, Yale Law, hard-to-get service medals.

I’m not saying I like the guy, but his knowledge and background should not be underestimated as some nearby are doing.

Jewish/socialist physicists:atomic weapons::”foreign“ AI scientists:automated targeting

I’m not looking forward to the loss of innocence of computer science that is parallel to that of physics from 1945 onward, but here we are.

Comments URL: https://news.ycombinator.com/item?id=46969657

Points: 3

# Comments: 0

It turns out that yes, better forecasts is a large part of what motivated the launch of this instrument.

High-spectral-resolution IR spectra at GEO allow estimation of vertically-resolved temperature and water vapor (over large spatial areas, at high temporal cadence), which are then assimilated. Forecasts and nowcasts thus improve.

These "spectra-to-get-temperature-and-water" measurements were pioneered by other instruments in LEO (e.g., NASA's AIRS, https://airs.jpl.nasa.gov/mission/overview/), but LEO does not provide enough coverage to help forecasts.

To understand the benefits of GEO IR spectra, we do "OSSE's" (Observing System Simulation Experiments) to quantify how much improvement you get. You take a "Nature Run", make simulated observations (existing and proposed), and see if there is an improvement. (Since the Nature Run, which you made, provided ground truth, you can judge if there really was an improvement.)

Thankfully, many people have already done this. See: https://www.ssec.wisc.edu/geo-ir-sounder/osse/

In particular, looking at the figure there from Li et al., compare panels:

* (d) -- (Nature Run) - (existing data) ("CNTRL")

* (e) -- (Nature Run) - (existing data + GEO IR)

which both show differences between the Nature Run (NR) and the forecast.

The RMSE improvement (on a CONUS storm) is given as RMS of 0.55 (existing) versus 0.43 (with GEO IR), in degrees Kelvin. So that's 0.12 Kelvin or 0.22 Fahrenheit. Also, and probably more interestingly, the spatial pattern changes.

There are a lot of OSSE's reported on that page for these sounders. NASA is also conducting OSSE studies for a more ambitious multi-spacecraft observing system (https://science.nasa.gov/earth-science/decadal-surveys/decad...).

Studies like this (i.e., OSSEs like the ones above) are one of the main ways we decide how to build the next instruments -- what provides the most benefits vs. cost, which system parameters to push to improve and which are good enough.

They say they hope to retrieve trace gases at that global scale (seemingly with 30 minute cadence), which I think would be new. Also, they seem to say that this spectral resolution would enable them to retrieve temperature and humidity as a function of height -- not just surface temperature and column-integrated water content ("humidity").

Aha, here's a nice link (https://www.ssec.wisc.edu/geo-ir-sounder/) on exactly this question, pointing out the NASA IR sounders that have existed for many years (AIRS). These instruments get vertically-resolved atmospheric information, but they are not at GEO so their coverage is different. This makes them less useful for NWP.

@vicapow replied to keep the Dropbox parallel alive

In mathematics/applied math consider cited papers claimed to establish a certain result, but where that was not quite what was shown. Or, there is in effect no earthly way to verify that it does.

Or even: the community agrees it was shown there, but perhaps has lost intimate contact with the details — I’m thinking about things like Laplace’s CLT (published in French), or the original form of the Glivenko-Cantelli theorem (published in Italian). These citations happen a lot, and we should not pretend otherwise.

Here’s the example that crystallized that for me. “VC dimension” is a much-cited combinatorial concept/lemma. It’s typical for a very hard paper of Saharon Shelah (https://projecteuclid.org/journalArticle/Download?urlId=pjm%...) to be cited, along with an easier paper of Norbert Sauer. There are currently 800 citations of Shelah’s paper.

I read a monograph by noted mathematician David Pollard covering this work. Pollard, no stranger to doing the hard work, wrote (probably in an endnote) that Shelah’s paper was often cited, but he could not verify that it established the result at all. I was charmed by the candor.

This was the first acknowledgement I had seen that something was fishy with all those citations.

By this time, I had probably seen Shelah’s paper cited 50 times. Let’s just say that there is no way all 50 of those citing authors (now grown to 800) were working their way through a dense paper on transfinite cardinals to verify this had anything to do with VC dimension.

Of course, people were wanting to give credit. So their intentions were perhaps generous. But in no meaningful sense had they “read” this paper.

So I guess the short answer to your question is, citations serve more uses than telling readers to literally read the cited work, and by extension, should not always taken to mean that the cited work was indeed read.

The real challenges there aren't the "biggies" above, though, it's the ones in obscure journals you have to get copies of by inter-library agreements. My PhD was in applied probability and I was always happy if there were enough equations so that I could parse out the French or Russian-language explanation nearby.

I'm sure people made mistakes on their bibliographies at that time as well!

And did we all really dig up and read Metropolis, Rosenbluth, Rosenbluth, Teller, and Teller (1953)?

Edited to add: Someone made a chart! Here: https://papercopilot.com/statistics/neurips-statistics/

You can see the big bump after the book-length restriction was lifted, and the exponential rise starting ~2016.

https://loa-shared.s3.amazonaws.com/static/pdf/Didion_Malibu...

I share some of the same disappointment, especially going back and noticing disinvestment in the schools, which were one of the gems of the area.

The southern end of the central valley (San Joaquin region, whole central valley is outlined in red) is particularly hard-hit by groundwater depletion. Some of that storage does not come back, because the ground compacts after the groundwater is withdrawn.

A moment's reflection should make this clear. It's such a fundamental resource, touching everything we do. We just tend to take it for granted.

E.g.: https://en.wikipedia.org/wiki/Matilija_Dam#History

> Almost immediately after construction, the dam began silting up. The dam traps about 30% of the total sediment in the Ventura River system, depriving ocean beaches of replenishing sediment. Initially, engineers had estimated it would take 39 years for the reservoir to fill with silt, but within a few years it was clear that the siltation rate was much faster than anticipated.

There are similar sites all over the state. If you happen to live in the LA area, the Devil's Gate Dam above Pasadena is another such (but originally built for flood control, not for storage).

It's just not as easy as GP comment imagines.

(Related, and profound apologies for the fb.com link: https://www.facebook.com/DLJCSS/posts/small-quakes-do-not-pr...)

(Source: Work with Earth science domain experts in $dayjob, and am often surprised when my basic intuitive arguments turn out to be wrong.)

It's worth noting that they are mostly interested in critical phenomena in general, and earthquakes are kind of a drive-by application, treated along with fires and sand piles.

They do hint around the edges, but they don't head-on make the claim for earthquakes that small EQs materially lessen stress buildup and thereby make larger EQ's less likely.

I was looking for a credential of one of the people they interview, to see if they are really a solid earth person or more of a critical phenomena person -- their names aren't easy to find. This particular myth ("small earthquakes relieve stress") is a bit of a stinker in the solid earth community, and I think a solid earth person would be quite careful about their words as they discuss this.

The above link does not answer that question. It is relating stress release to "fault strength", or the maximum shear stress that can be withstood by the fault. There is an incidental relationship with depth that plays a role.

The video linked nearby (on criticality) also does not address the question at issue.

I'm only replying because I work adjacent to this area, and my understanding is that the idea that small EQ's release stress is a myth. Here [1] is another link, listed as #1 in the "Myths" category. And you can dig up quotes from none other than Lucy Jones [2] saying that this is a myth.

I don't work directly in this area, so I'm not willing to say absolutely no. But I'd really like to see a head-on reference supporting the claim that it's not a myth.

[1] https://earthquakes.berkeley.edu/outreach/faq.html

[2] https://en.wikipedia.org/wiki/Lucy_Jones

I feel like I’m being a bit curmudgeonly, but I don’t read them much any more.