A Foggy Day

(Note: I updated this post several times, after initially posting it, by accident, sooner than I had meant to.)

After a weekend that really started to feel like summer, it was cold this morning in New York City this morning, with a thick fog. Here is a photo I took from the George Washington Bridge at about 11:30 AM, looking south along the Hudson. See the boat in there?


The weather service’s forecast discussion calls it an “advection fog”, which means it happens when warm, moist air moves over a cooler surface, and ascribes it to a “back door cold front”. The modifier “back door” refers to the fact that while most cold fronts – like most weather of any kind at our latitude – come from the west, this one came from the east. You can see it in this image, a map of the flow this morning. The arrows show the flow at 1000 hPa (near the surface), and the colors show the temperature there. You can see the cool air blowing into NYC from offshore:


The definition of advection fog is that it forms when relatively warm, moist air moves over a cooler surface, so that it cools by contact with that surface and eventually reaches saturation. I’m not sure if that’s happening here, at least not in the short term. It looks as if the air was already cool before it blew onshore. But the key thing is that the layer of cool, moist air over the sea is very shallow and topped by a temperature inversion, so that warmer air overlies it. This means the boundary layer is very stable, and the air near the surface won’t easily mix with that above. Thus while over the ocean, the air took on more and more water vapor and couldn’t get rid of it, and eventually reached saturation. The sounding from this morning at Upton, NY in Long Island shows it very clearly:


Look at the bottom: there is only a single white curve until somewhere above 950 hPa (see the blue numbers at left which give the pressure) This means the temperature and dew point are the same, which means the air is saturated. I.e., fog. Then the steep jump to the right means a temperature inversion; it’s a good couple of degrees C warmer at 900 hPa (roughly 1 km up) than at the surface. Now look at the wind barbs at bottom right, showing the easterly flow just right near the surface, taking that cool foggy air in from offshore, while just a little ways up we have west to northwesterlies.

To get even nerdier:

Actually, there are at least four distinct layers in this sounding. 1. The cool fog layer at the surface. 2. Above the inversion, just above 950 hPa, a layer that is close to saturated, but not quite (the two white lines are separate, but near each other, indicating temperature is just a little greater than dew point. The lapse rate is a little steeper than moist adiabatic (temperature angling to the left of the white dashed curve) which, given how close to saturation, suggests this air is almost unstable to a little elevated convection? 3. Atop that, between around 700-600 hPa, a roughly isothermal layer – very stable, close to being another inversion in that there is a slight temperature increase – in which the humidity drops steeply. 4. Above that, an atmosphere that is close to moist adiabatic in its temperature structure, but very dry.

I won’t try to do a whole analysis of this structure here, but it’s fascinating!


Tropical Pacific goes wild

Here in NYC, it’s cool and wet, while the ice slowly finishes melting and spring struggles to take hold. No big excitement, really. In the tropical Pacific, on the other hand, everything is happening at once.

At this moment there are two tropical cyclones (TCs – the generic name for hurricanes, typhoons etc.) in the southern hemisphere, both in the Pacific. Tropical Cyclone Pam just wreaked havoc in Vanuatu, ripping through that small island state as a category 5 storm. Here’s a visible satellite closeup:


And Nathan is offshore of northern Australia right now. Briefly, yesterday, there had been three at once in the southern hemisphere, with Olwyn making landfall in Western Australia (coming from the Indian ocean, that is, rather than the Pacific) in addition to Pam and Nathan. Australia had seen several cyclones already this season before that; a couple of them, Lam and Marcia, were quite intense. It is around the normal peak TC season in the southern hemisphere now, but even so this moment is exceptionally active. At the same time, there is even a weak one in the northern hemisphere, Tropical Storm Bavi in the Western North Pacific, where this is normally about the deadest part of the year.

Why is the Pacific going so nuts? A proximate factor seems to be that the Madden-Julian oscillation (MJO) is nearly off-the-charts strong right now, with its active phase right in the central Pacific. (If you have never heard of the MJO, but are interested to know about the most important mode of weather and climate variability in the couple-weeks time scale range, you can start with my old blog posts here, here, and here.) The MJO tends to spin off TCs as it moves slowly eastward. So we can hold it partly responsible for some of the Australian activity as it was there around 7-10 days ago, and now the Pacific storms.

There’s also now an El Niño officially underway, which can help to jack up TC activity in the Pacific. It is probably temporarily helping to amp up the MJO as well, as the signals associated with the two are briefly in phase. It’s a weak El Niño event by standard metrics, but it’s possible for that to be the case while still its impact on TCs is strong. In fact, when it was hurricane and typhoon season in the northern hemisphere, last northern summer and fall, the whole season looked very El Niño-like even though an El Niño had not yet been declared to exist by most forecasters, but was limping along just below their thresholds for calling it. The Atlantic was quiet, the Eastern Pacific was gangbusters, and the Western Pacific had a large number of very powerful typhoons, all typical of El Niño years.

Apart from Pam’s destruction in Vanuatu, these storms have been doing relatively little damage – compared to what they could have done, given their intensities. The Australian landfalls, in particular, have largely spared population centers. But it’s been an impressive display of atmospheric power.

This harsh winter: the improbable occurs

It’s 10 degrees Fahrenheit in New York City as I write this, with an overnight low that will get close to zero (Fahrenheit). It has been cold in the northeast US for weeks, and is forecast to stay cold for weeks more. Boston is being choked by snow from multiple major storms – two of which have been in their all-time historical top ten for snow accumulation – and stands a good chance to break the all-time record for most snow in a season.

I wrote a post back in October about the coming winter. The main point of the post was that seasonal forecasts in general, and for the northeast in particular, have large uncertainty and not a huge amount of skill.

I concluded by saying that

“Without looking at any weather data or models, one can say pretty confidently that it is very unlikely that this winter will be as cold as last winter was in the eastern US. Last winter was very extreme by historical standards, so a winter that extreme is – basically by definition – improbable in *any* year. No information currently available (including the state of El Nino), or that will be available ahead of time, is strong enough to change that. Again this is a probabilistic statement: it’s not impossible that this winter will be as cold or colder than last, it’s just very unlikely.”

I haven’t seen the statistics to prove it yet, but I think it may well turn out that for the northeast at least, this winter in fact is going to turn out more severe than last. In terms of snow in much of New England, it certainly is already, and I think with the current cold snap – projected to last another two weeks in virtually the whole eastern US, as per NOAA’s latest 8-14 day forecast (shown below) – we are headed to beat last year in terms of cold as well.


I stand by my claim that this was improbable, as far as the scientific information available in October would have told us. But the improbable seems to be occurring.

How the California drought is like Sandy

Richard Seager and I have an op-ed in today’s Los Angeles Times about how the current drought in California is like Hurricane Sandy in New York. We’re not thrilled with the title (which we didn’t write, nor get to review before publication) as it seems to imply some possibility that human-induced climate change might not be occurring. We do not say nor imply that in the piece; quite the contrary. But ok, that’s the deal when you send things to newspapers. We’re very appreciative that they ran it, and hopefully the main messages come through to anyone who reads past the title.

Denial among physicists, part 2

Today I continue my account of my experience with climate denial among physicists at a conference I attended a few weeks ago. The first installment of this account is here. There were three outspoken deniers at the conference, two of whose talks I heard. This post is about the interaction I had with the third one. This interaction began at the end of the first talk of the conference.

The speaker, a relatively young climate scientist, presented a piece of research using numerical models to assess how various human influences (including but not limited to greenhouse gases) affected a particular aspect of the 20th century climate record in the United States. The questioner, the physicist about whom I’m writing today – let’s call him Denier 3 – raised his hand at the end and asked if the speaker had considered the criticisms of climate models made by a scientist not present at this conference, a climate scientist famous for his denialist position (let’s call him “Famous Denier”). This telegraphed the views of Denier 3, not least because the substance of the question was only tangentially related to the substance of the talk, and thus came across as a broadside against the field of climate science as a whole.

In the course of his question, Denier 3 also volunteered information about himself. Climate science was not his field; he had spent his career (he was clearly quite senior) in another area of physics.

There was another talk, and then a coffee break. During the break, Denier 3 was talking with the first speaker, to whom he had asked his question. The speaker was the only person I knew at this conference, and they were standing straight ahead of me as I walked out the door of the auditorium, so I joined their conversation. They were again discussing the views of Famous Denier. I volunteered that in the 90s (when the evidence was a little less overwhelming than today, and Famous Denier could still be characterized as a skeptic posing criticisms of the mainstream view that had some legitimate substance) Famous Denier’s position on climate had some honor, but that it didn’t any more.

Denier 3 said “Your field is very prone to ad hominem attacks.”[1] I answered, not trying to disguise my irritation, “Oh, please. Give me a break.”

We talked a little more. It was quite clear that we disagreed about a lot, but neither of us was speaking in heated tones. Denier 3 said that in his career he had done research on topics in physics that were related to developing climate adaptation measures. He was of the view that climate change was happening, but he was not convinced it was human-induced. In the organization he worked for, he said, they had decided that since the human role in climate change was controversial, they had decided to focus instead on what we could do to adapt to it, rather than worrying about reducing greenhouse gas emissions. I answered that adaptation measures are fine, but that the notion that the influence of human greenhouse gas emissions is significant – to the point of having been responsible for the majority of the observed warming in the 20th century – is not controversial within the community of actual climate scientists. It’s controversial only in the view of some people outside the field who refuse to accept the results of climate science.

I went on to say that it frustrated me that some physicists, in particular, believed that because they had some expertise in other areas of physics, they could understand climate science better than practicing climate scientists, even without having studied the evidence or methodologies of climate science carefully. I characterized this as an arrogant attitude. I was careful at that point to say that I was not necessarily attributing this arrogant view to Denier 3, to whom I was speaking (although by this point it was clear that he did in fact hold this view). Denier 3 said “And your view is not arrogant?” I said “My view is that those who spend all their time studying a given problem have a better claim to knowledge about it than those who don’t. If that strikes you as arrogant, then you can consider me arrogant.”

Denier 3 told me that he was involved in a study group on climate within the American Physical Society. He asked me if I would be willing to attend his study group and discuss the science there, possibly with people whose views were contrary to my own[2]. I answered that there were already many study groups on climate – that in fact, we have a whole field of people who do nothing but study climate, and they already gather in many groups, and have been doing so for many years, not least of which is the IPCC. I asked what was different or better about his group than all of the others.

Denier 3 said that he wanted to “figure out the Hamiltonian of the climate.” The original speaker (the young climate scientist) and I at first thought Denier 3 meant this literally. The Hamiltonian is a concept from physics that applies to many problems, and in fact some have tried to apply it to aspects of atmosphere and ocean physics; we mentioned these attempts and said that while one could pursue this avenue, we didn’t think it would be useful for the problem of global warming, for reasons we stated very briefly.

Denier 3 said that he had meant his statement about the Hamiltonian as a “pun”[3]. He said “Let’s figure out the Hamiltonian before doing vertex corrections.” After this clarification that he didn’t mean it literally, we understood this as physicist language for solving the more basic and fundamental problem before moving on to details. Though neither of us interrupted right then to say it, the implication that climate scientists don’t already think this way – that we somehow are focused on details without seeing the big picture – is both false and insulting, implying again that we are somehow inferior to those in other areas of physics. Denier 3 continued that what he really meant was “Let’s study the climate.” I said “We do study the climate. A whole field of us, many many people, has been doing this for many decades. You think you are the first to think of this? You think it has not been done?” He said “I don’t know what has been done.” I said “Well perhaps you should find out!”

I think this captures the essence of it. Physicist admits that he doesn’t know much about climate science, and yet feels justified in dismissing the consensus view that has come out of that field. Physicist believes that what is needed is for a real physicist like himself to just sit down and study the climate. When told that many people – a large fraction of them trained in physics – have been doing this for many years, physicist does not find this relevant information. (Denier 3 gave no indication that my statements to him would influence his views, even though he offered no counter argument other than to again accuse me, when I objected strongly to another one of his statements, of “ad hominem attacks”.) What is this if not denial?

I do not believe that most physicists, and certainly not a majority of the best ones, think as this person does. I do not think most of the physicists at this conference think this way – none of those I spoke with, other than the three already mentioned, did. I believe that most physicists respect the work of their colleagues in climate science, as they would respect the work of their colleagues in any field of physical science. Whatever questions they may have, whatever skepticism or uncertainty, they don’t believe it is appropriate to publicly challenge the hard-earned consensus view of an entire field without first doing their homework.

(The public position of the APS is one of agreement with the mainstream view of climate science, as of its last public statement on the matter . A new statement is in the works now; I will be very surprised if the essence of it changes, even though the APS has bent over backwards to accommodate denialist views in the process leading up to that new statement.)

But when it comes to those physicists who do hold denialist views on climate without having either done any research in the field or read the existing research, it’s that lack of respect that angers me. I try to imagine what the reaction would be if physicists in another (non-climate) area – say, quantum computing – were to hold a conference, and physicists from yet another area – let’s say, high-energy nuclear physics – were to show up at their conferences and tell them, without having read up carefully on quantum computing, and lacking the knowledge to make substantive criticisms of the mainstream views in that field (beyond, perhaps, superficial ones that had already been exhaustively addressed and refuted in the quantum computing literature), that they had it all wrong. I don’t think it would go over too well. Why is it ok to do it with climate scientists – who are, after all, nothing other than applied physicists who focus their research on the atmosphere and ocean?

[1] I don’t know much Latin, and I couldn’t have cited at that time the exact meaning of “ad hominem”. I knew that it meant a personal attack of some kind, and that that was an inappropriate description of my statement – or at least, a cheap way to avoid having to defend the actual content of Famous Denier’s views. It struck me as a form of the appeal to “civility”, a well-worn tactic for derailing debates about important things into arguments about tone rather than substance. I looked it up later, though and indeed ad hominem describes a statement about someone’s views which derives its negativity from association of those views with the negative attributes of the person holding them. It is the opposite of the appeal to authority, in which one claims something must be right because someone who should know said it. My statement was not ad hominem at all. I did imply something negative about the character of Famous Denier, but only because of his public views, not vice versa.

[2] The invitation to debate is another standard denialist tactic. It carries the implication that climate science is otherwise free of debate, and that denialist views, rather than having lost the argument by the standard processes of science, have instead been suppressed by some form of political correctness.

[3] A pun means a play on words; I don’t see one here.

Sandy anniversary media roundup, and Secret Science Club

Yesterday was the two-year anniversary of the landfall of Post-Tropical Storm Sandy. The occasion was marked by a brief spate of Sandy-themed media stories. I was part of a few of those, so the book got some attention. In the midst of this self-promotion, I did my best to take a few moments to remember the disaster itself and those who suffered grievous losses because of it.

But, ok, here is an account of the various media and things. The Sandy anniversary wasn’t about me, but this blog kind of is, right?

Most prominently, I had the opportunity to be a guest on the Leonard Lopate Show on WNYC. The podcast is here – it’s around 40 minutes long!

Then, one thing that was not media per se, but a live event featuring an actual audience: on the evening of Tuesday October 28 I had the pleasure of giving a talk for the Secret Science Club, at the Bell House in Gowanus, Brooklyn. (Here is a detailed account of my talk by an audience member, whom I didn’t have the pleasure to meet.) I had done this once before, just a couple of weeks after Sandy.

If I had not been to these events, I wouldn’t have believed that they could exist. A scientist gives a talk in what is basically a rock club. The space holds a few hundred people, and it pretty much fills. The crowd is incredibly enthusiastic, and asks questions afterwards for as long as time permits – the organizers, Margaret Mittelbach and Dorian Devins, have to shut the Q&A down after a while. What is most remarkable about this is that most of the scientists who speak are not celebrities. I, for example, am no Neil DeGrasse Tyson. Yet several hundred people turn up, regularly, to hear what are – at least in my case – nothing more than power point science talks.

In the routine activities of scientists, we never have this experience. I have given many, many talks, but have never  had the kind of reaction that I got from these audiences. No matter how good a talk one gives to a room full of scientists, they never get that excited. They have heard many, many talks, and are jaded. It’s a newer experience for these people who come to SSC, I guess. In any case they are definitely not jaded, but respond as though they were at a theatrical performance. Or a comedy show. I have never had so many people laugh at my jokes.

What the SSC made me think the first time, and still does, is: if this can be a thing, can it be ten things? If you can fill a big performance space once or twice a month with people listening to science talks, could you fill many more, many more often? Could we have as many evening venues for science as we have for comedy, theatre, or music?

Anyway, then here are a few online articles in which I was quoted in the last couple days (in some of them at great length):

Climate Central story on how Sandy has inspired new research in the last two years.

Vice News story on New York City real estate and FEMA flood zones.

Salon story (via alternet) that’s not about Sandy at all, but about the seasonal forecasts for next winter; this is the one that led to my blog post last week.

New Jersey Star Ledger opinion piece by Paul Mulshine based in large part on a phone interview with me.

Book things

Storm Surge got a nice review in Publishers Weekly. Here it is quoted in its entirety:

“Hurricane Sandy hit metropolitan New York hard in October 2012, knocking out power while ruining homes and businesses; it turned parts of Manhattan into swampland, flooded subway stations and transit tunnels, and devastated much of the Jersey shore. Though the damage it caused is irrefutable, the cause of the hurricane itself, says Columbia University atmospheric scientist Sobel, is up for debate. In this comprehensive volume, he looks at the science behind Sandy (and similar weather systems), examining the circumstances leading to it—”the left turn it took” in the ocean in “a radical departure from all known meteorological history”—and factors that made it a superstorm. How did it complete “its transition from a tropical cyclone to a mammoth hybrid”? Sobel diligently re-creates a timeline, from the early warnings issued by the National Hurricane Center to government evacuation orders to the impact Sandy had once it made landfall. Along the way, he provides substantial background information on what, exactly, a hurricane is and how the Fujiwhara effect—named for Japanese meteorologist Sakuhei Fujiwhara—applies to dueling vortices. Topics like these make for interesting, if technical, reading, and Sobel manages to strike an effective balance. (Oct.)”

And, Kevin Krajick has posted an interview piece with me on the Columbia Earth Institute State of the Planet blog.


I spent yesterday at the Northeast Risk & Resilience Leadership Forum, in the Marriott Hotel in Stamford, CT. This is an event put on by the Risk Sciences Foundation, which is connected to the reinsurance company Renaissance Re. It was a one-day meeting on the risks faced by the northeast US coasts due to storms, sea level rise, and climate change: what the risks are, and what governments, private companies, and anyone else might do about them. With its two-year anniversary coming up, Sandy loomed large.

This meeting was different than my usual. I go mainly to scientific conferences, where the speakers are mostly other research scientists and everyone talks about scientific research. There are sometimes a few people with a policy bent, but they’re a minority, and they don’t change the dynamic much; they come to keep up with the science.

The crowd at this meeting was more eclectic. One wouldn’t necessarily think of the different groups who showed up as being similar, but they share an interest in the theme of coastal risk. Beyond that, they share a set of concepts and understandings about what could be done better.

Of course you had your insurance and reinsurance people; they organized the meeting. Then there were people whose jobs are about making housing more disaster-resistant, through building codes and the like (Federal Alliance for Safe Homes, Insurance Institute for Business and Home Safety). This group is connected with the insurance industry but doesn’t actually sell insurance. There were people from government agencies – federal (including one U.S. senator and one Obama administration official), state, and local; some had titles that wouldn’t have existed too many years ago (e.g., “Chief of Environment, Energy and Open Space” or “Senior Policy Advisor, Climate Change and Insurance”). Then you had various nonprofits of a more or less environmental bent (National Wildlife Federation, Union of Concerned Scientists). And finally, a few academic scientists.

All these people agree that we don’t take the risks from coastal storms seriously enough, and that more money and effort should be put into pre-disaster “resilience” (ultra-trending buzzword of the moment) rather than just post-disaster recovery.

There are differences of emphasis in how the different constituencies would do this. The nonprofit types advocate for green infrastructure, ecosystem restoration, and sustainable development – including slowing or even reversing development in the most vulnerable coastal areas. Insurance people (and ok, a lot of others) advocate for reform of the National Flood Insurance Program to make it solvent – exactly as the Biggert-Waters act did, before it was substantially rolled back – and thus to de-incentivize development in those risky areas by raising rates there. Housing people advocate for better housing.

There was no contentious argument about which of these was more important. Rather, there seemed to be consensus that all of them are good, all are complementary, and none are being done enough now.

The scientists, like me, just advocate that everyone should pay attention to the science. (I argued that sea level rise is the most important factor increasing risk, at least as far as we can say now with certainty; changes in storms may well be important too, but are more uncertain and will take longer to show up above natural variability). That wasn’t a hard sell here; if there were any climate change deniers in the house, they stayed silent.

The fact that this was true at a meeting organized by a reinsurance company is big by itself. The insurance industry is not Greenpeace or 350.org; they take climate change seriously for purely business reasons. Given the way the political discussion around climate is often cas in this country, insurance (or reinsurance) companies do us all a service by talking about it publicly. (The US military is perhaps the other organization that takes climate change most seriously while conforming least to any stereotype that one might associate with that stance. There were no military at this conference to my knowledge, but there was Alice C. Hill, high up in Obama’s Homeland Security team. She said “Climate change is a threat multiplier.”)

While a lot of interesting people said a lot of interesting things, I was mainly impressed just by how well this diverse group hung together. There should be a name for this collection of people that captures their shared interest and purpose. I hereby propose “riskies”.

Rapid intensification – Vongfong update

This is the down side of trying to blog an extreme weather event in real time while holding down a full time job as an academic. Just can’t keep up.


When I wrote my previous post on Typhoon Vongfong (shown above in a recent visible satellite closeup, from this great site) last night, Vongfong’s winds were estimated at 90 knots, and the Joint Typhoon Warning Center (JTWC) had forecast that it would intensify to 130 knots over the next 48 hours. When I woke up this morning it was estimated at 120 knots already; it’s now at a screaming 155 knots, or 178 mph (per JTWC).

The NHC defines “rapid intensification” as an increase of 30 kt in 24 hours, so Vongfong has definitely undergone rapid intensification. It was not forecast, but it rarely is. While tropical cyclone track forecasts have improved steadily for decades, intensity forecasts haven’t, and the difficulty of forecasting jumps like Vongfong just made are a big part of the reason.

It’s not just the forecast of the storm’s future that’s the issue, though. Even estimating its intensity at the present moment poses challenges. While JTWC is calling it 155 knots – the very upper end of category 4, pushing category 5, the top of the scale – the most recent estimate from the Japan Meteorological Agency (JMA) puts it just at 115 knots, low category 3. Some of this difference is attributable to the different standards; JTWC uses 1-minute averaged sustained winds while JMA uses a 10-minute average, which tends to be a little lower. But that isn’t the whole story.

In fact, no one is measuring the winds in Vongfong. There is no routine aircraft reconnaissance in the Western Pacific to make direct observations. The estimates all come from analysis of satellite observations, and satellites don’t measure the winds directly. The satellite images used to estimate intensity see some combination of clouds and water vapor, and either human analysts or automated pattern recognition algorithms use those to infer the wind speed. (To get some idea how it’s done, try this.)

There’s no doubt that Vongfong is a very powerful storm. The forecast models are mostly predicting that it will start to weaken by a day or so from now, perhaps after holding steady or even intensifying a bit more before then (see for example a collection of current forecasts on Kerry Emanuel’s page). The track forecasts are still taking it over Japan early next week. Assuming that pans out, as seems likely, the question is just how rapidly Vongfong loses its currently formidable head of steam.