Month: September 2021

I had never seen galaxy images like this before. Nobody had! These images highlight regions of star formation in nearby galaxies. There are still a number of unanswered questions about how star formation actually works. To answer these questions, we observe galaxies that are actively forming stars in giant gas clouds. Until recently, we did not have the necessary resolution to clearly image the individual gas clouds themselves. But images released by a project called PHANGS (Physics at High Angular Resolution in Near GalaxieS) in a collaboration between the European Southern Observatory Very Large Telescope and the Atacama Large Millimeter / Submillmeter Array (ALMA) have details never seen before of star formation clouds shown in other galaxies.

This image combines observations of the nearby galaxies NGC 1300, NGC 1087, NGC 3627 (top, left to right), NGC 4254, and NGC 4303 (bottom, left to right), captured with the Multi-Unit Spectroscopic Explorer (MUSE) ESO’s Very Large Telescope (VLT). Each individual image is a combination of observations made at different wavelengths of light to map star populations and warm gas. Picture and picture description PHANGS / ESO. Original picture

A cloud of stardust

Stars are formed from giant molecular clouds (GMCs), which are mainly composed of molecular hydrogen (H2). Gas in these clouds collapses under gravity and eventually becomes dense spheres. Due to the increase in density and pressure, the heat in these spheres enables nuclear fusion, in which hydrogen is fused into helium – a star is born! But what triggers the initial collapse of the gas? Does the star formation rate vary between different clouds in the same galaxy? How diverse are the clouds themselves? These are all chapters of star formation that we are not entirely sure about. Enter PHANGS.

The PHANGS researchers selected the target galaxies on the basis of a number of requirements. The galaxies had to be close enough that they could be imaged with the necessary resolution to see individual GMCs. All targets are therefore within 17 million parsecs of the Milky Way (about 55 million light years). The galaxies are also not tilted too much to allow a clear line of sight into the disks of the target galaxies. And perhaps most importantly, the target galaxies are actively forming stars. As “main sequence galaxies”, these galaxies form stars in their disks without the external gravitational interaction of a nearby galaxy or as a result of galaxy mergers, both of which can trigger intense phases of star formation, known as starbursts. Rather, these galaxies form stars through processes within the galaxy. Ninety such galaxies met the criteria and were selected for the survey.

These contrasting images show the increased resolution in carbon monoxide detection. The left side shows previous surveys of cold gas clouds in the galaxy NGC 3627 compared to the increased resolution of the “cloud scale” achieved by PHANGS-ALMA, which shows a much clearer picture of the GMC positions in the galaxy. c PHANGS-ALMA

Cold and dark

The discovery of star formation regions in the target galaxies is achieved through a combination of the discovery of cold gas and hot gases heated by newly formed stars. Cold GMCs that give birth to new stars are known as star nurseries. They can be tens to hundreds of light years in diameter, with mass equivalent to thousands of suns. However, the hydrogen that makes up these clouds is difficult to see. When hydrogen is exposed to energy, it glows and is easily detectable, while cold hydrogen hides in the darkness of space. However, GMCs also contain carbon monoxide (CO), which is easier to spot when cold than hydrogen. The ratio of CO to hydrogen in GMCs is understood as a constant and so the amount of CO molecule detected can tell us how much hydrogen is in a given cloud. It is this CO signal that ALMA is looking for.

This picture shows the distribution of cold (CO) vs. hot (H-alpha) gas spread across multiple galaxies (the colors in this diagram are not intuitive). The cold CO gas signatures are mapped by ALMA, while the scorching hot H-alpha is mapped by the VLT. The combined map shows where emerging stars are being born in the cold GMCs. c PHANGS-ALMA

As soon as hydrogen is excited by the energies of newly emerging and young stars, it releases a light known as Hydrogen Alpha. H-alpha is the brightest feature in the spectrum of glowing hydrogen and is the way we observe much of the universe. The combination of the hot and cold maps of these GMCs in other galaxies shows the environment in which stars form. An instrument called MUSE on the Very Large Telescope maps the glowing H-alpha where ALMA detects the cold CO emissions. The finest details resolved by ALMA in the target galaxies have a diameter of about 100 parsecs (about 326 light years). The researchers note that this is a “cloud-scale” resolution because the target GMCs are also about 100 parsecs in diameter. With this resolution, the clouds can be distinguished as individual structures separately from the structures of their other home galaxies.

ESO’s Very Large Telescope (VLT) shows the nearby galaxy NGC 4303, a spiral galaxy with a bar of stars and gas at its center, located about 55 million light years from Earth in the constellation of Virgo. The golden glow mostly corresponds to clouds of hot hydrogen, which indicate the presence of newly born stars, while the bluish regions in the background reveal the distribution of slightly older stars.
C. PHANGS / ESO – original image

A next generation card

While VLT takes pictures in optical light, ALMA sees distant galaxies in infrared and radio wavelengths. These wavelengths are useful for observing structures that would not be visible in optical wavelengths such as cold gas. But there is a downside. Optical wavelengths can typically provide finer resolution for imaging, creating a tradeoff between visibility and resolution. The impressive achievement of this initiative is that these new ALMA images achieved a resolution in infrared and radio that was close to optical resolutions. The images are further enhanced by merging the optical resolutions of the VLT as well as data from the Hubble Space Telescope with other images.

NGC 4254 ALMA (orange / red) data from cold GMC clouds applied to data from the Hubble Space Telescope,
Photo credits: ALMA (ESO / NAOJ / NRAO) / PHANGS, S. Dagnello (NRAO) Original image mosaic of the ALMA recognition of star children in combination with Hubble space telescope data. The pictures show the diversity of the GMC star formation clouds from the nearby universe. C. ALMA (ESO / NAOJ? NRAO) / PHANGS, S. Dangnell (NRAO)

The level of detail is overwhelming. These are not individual photos of each galaxy, but mosaics. For comparison: The Trottier Observatory I am working on was able to depict Andromeda, a much closer galaxy with 2.4 million light years, in a six-photo mosaic. Every galaxy that was mapped in the PHANGS-ALMA project, despite its distance of tens of millions of light years, consists of mosaics consisting of up to two hundred individual images. The process of mapping all 90 galaxies at this level of detail spanned a total of 6 years, resulting in a new atlas of star nurseries – the next generation of stars to be born in the universe.

How are stars formed? – Video by Fraser Cain

100,000 star kindergartens were mapped between the 90 target galaxies. The results show that the position in a galaxy can change the way stars are formed. Clouds in central regions of the galaxy are more massive, denser and more turbulent than those in the expanses of the galaxy disk. The rate at which the clouds form stars, and the resulting final dissolution of the cloud by these new stars blowing the gas away, all seem to vary depending on where the cloud is in its home galaxy.

Atacma Large Millimeter / Submillimeter Array (ALMA) with a dramatic meteor overhead.
C. ESO / C. Malin

A common view

The facilities required to capture these images are powerful and quite picturesque in themselves. ALMA is not a large telescope, but an arrangement of 66 dishes spread over the Chajnantor Plateau of the Atacama Desert in Chile. The signals collected by the array are effectively combined to create a huge bowl. The individual dishes can also be rearranged depending on the needs of the respective project. The Very Large Telescope is also located in the Atacama and consists of four telescopes, two with 8.2m mirrors and two smaller 1.8m mirrors. Like ALMA, the telescopes work together effectively creating a larger telescope.

Telescope “Yepun”, one of 4 of the VLT telescopes shown here, which fires a laser with adaptive optics into the sky, which compensates for the distortion of the atmosphere and creates a sharper image. C. ESO / Y. Beletsky

Although these are the most detailed images of their kind, the resolution achieved by PHANGS-ALMA is just on the threshold that is required to image individual GMCs in the target galaxies. But now that these star-forming regions have been mapped, future telescopes like the upcoming James Webb Space Telescope and the Extremely Large Telescope (the next one will be Ultra Large, I assume) will be able to locate these GMCs with sufficient resolution to visit again to look into the clouds themselves for even more insight into star formation.

Cosmic origins

We were once part of a giant molecular cloud, you and me. Everything your body includes, the computer you are reading this on and the planet we live on started out of a huge cloud of stardust. The future of telescopic space exploration is so tempting. James Webb will not only have the opportunity to study star formation in nearby galaxies, but also to image some of the first stars ever to be born in the universe. The main mirror of the ELT will have a diameter of 39 meters! Its surrounding dome is the size of a soccer field. We are on the brink of views of the universe we have never seen before and ultimately new understandings of our own origins in the cosmos.

Feature picture: Image of the galaxy NGC 3627 in the constellation LEO. The golden gas glow corresponds to clouds of ionized hydrogen, while the bluish regions reveal the distribution of slightly older stars. Photo credit: ESO / PHANGS

More to explore:

Galactic Fireworks: New ESO Images Reveal Breathtaking Features of Nearby Galaxies | ESO (With the original pictures)

Cosmic cartographers map the universe nearby, revealing the diversity of star-forming galaxies – National Radio Astronomy Observatory (nrao.edu)

[2104.07739] PHANGS-ALMA: Arcsecond CO (2-1) imaging of nearby star-forming galaxies (arxiv.org) (Open Access original research paper)

PHANGS-HST | IPAC (caltech.edu)

A galaxy makes new stars faster than its black hole can starve for fuel – Universe Today

The universe in formation. Hubble sees 6 examples of the merging of galaxies – universe today

MUSE | THE

Atacama Large Millimeter / Submillimeter Array | ALMA (almaobservatory.org)

ELT | THE

A powerful new laser will improve adaptive optics – Universe Today

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Reposted from the Cliff Mass Weather Blog

In the New York area, more people died from “remnants” of Hurricane Ida last night than Louisiana and Mississippi, as one of the strongest hurricanes of the century hit a low-lying coastal zone. (Current number: about two dozen in the NY area, about 8 in Louisiana)

Think about it. And as I’m going to suggest on this blog, we can do a lot better, both in forecasting and communicating serious weather threats. Investment and new policies are needed.

https://www.youtube.com/watch?v=OQ89xWvNgls

Dramatic video of what happened last night

Heavy rain, flooding, and even tornadoes hit a relatively narrow band that stretched southwest-northeast of Pennsylvania and New Jersey across New York, Connecticut and Massachusetts, according to a recent rainfall analysis by the NOAA / NWS Weather Prediction Center for the 48th shows -h ends this morning at 6 p.m. EDT (see below).

Quite a large area of ​​over 6 inches of rainfall with some places reaching 8-10 inches.

Much of this rain fell during brief, intense downpours associated with thunderstorms. Newark, NJ, seasoned 3.24 inches in an hour, with NY hit Central Park by 3.15 inches in an hour. Both are hourly records for these sites.

The intense convection (thunderstorm) of the rain is illustrated by a weather radar image last night at 9:50 p.m. EDT, with the red colors indicating exceptionally high rates of precipitation.

Upon landing, Hurricane Ida turned into a tropical storm and then passed an extra-tropical transition where it assumed the characteristics of a medium-latitude cyclone. The National Weather Service sometimes calls the resulting storm a post-tropical cyclone.But there is a real danger in this transition.
Extra-tropical cyclones have strong upward movement, often associated with frontal zones where temperatures and winds change rapidly. And transitional tropical storms often bring with them large amounts of tropical moisture, which can lead to heavy rainfall, as the humid air is forced to rise by the storm circulation. This moisture can very quickly be converted into rain during strong thunderstorms / convection. That’s exactly what happened last night.
Below is a map of sea level pressure and atmospheric humidity (called rainwater) for last night at 10:00 p.m. PDT; You can see the low pressure center and the plume of moisture (green colors) moving from the southwest.

To the east of the lower center, there was a warm front, as indicated by National Weather Service analysis for 8:00 p.m. EDT (indicated by the black semicircles).

The warm front had warm south winds on the south side and cooler east winds on the north side, with the warm, moist, unstable air in the south being forced to rise by the front, causing heavy convection showers in the north line. That is why the intense rainfall ran parallel to the front.
The forecast
My colleagues from the National Weather Service almost always issued warnings of heavy rainfall and the potential for flash floods yesterday, with a flash flood advising to watch out more than a day in advance.

Our models were useful, but had some intensity and position issues. High resolution is critical to this type of forecast for many reasons, including the convective nature (thunderstorms) of the heavy rainfall and the sharp frontal boundary that helped create the rain. 3-4 km grid spacing is a practical minimum.
The highest resolution model that is run by the National Weather Service several times a day is the HRRR model … the High-Resolution Rapid Refresh model that runs on a 3km grid. The total precipitation for a run that started at 8 a.m. on Wednesday for precipitation for the next day showed the gang but was shifted slightly to the north and underplayed the precipitation intensity a little.

The National Weather Service also runs a small (7-8 member) ensemble of several high-resolution simulations (approx. 3 km grid spacing) called HREF. Better.

Anyone who deals with numerical weather forecasting knows what this country needs in order to get such forecasts right: a relatively large (30-50 members) high resolution (3 km or better for grid spacing) ensemble of predictions carefully calibrated to provide good probability / uncertainty predictions.
Committee by committee, workshop by workshop have recommended this. This is what the National Weather Service’s own modeling experts say.
But the investment is never made to do so. This means acquiring the necessary computer resources and setting up the modeling / statistics post-processing system. Very, very frustrating that this critical ability is being postponed into the future. (Senator Cantwell, please do this!)
communication
We obviously failed last night. About a dozen people died in flooded cellars. Many people took to the flooded streets. Abandoned cars were parked everywhere.
The time-dependent warning process consists of two phases. Yesterday, hours before heavy rain, it was clear that a serious event was imminent and that people must be warned to stay off the road and prepare.
By late afternoon it was clear that a serious event was imminent and we had to get the message across to the people not only to get out of the street, but also to get out of the low-lying basement apartments. That didn’t happen.

Newark Airport
There’s no reason so many people died last night from an event that we knew was coming and that we could observe with weather radar and surface observation.

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Supply chains have been wreaking havoc across the industrial world.  The complex web that holds the world’s economies together has been fraying at the edges, resulting in some unexpected shortages, such as a lack of rental cars in Alaska and a lack of Lunchables at the author’s local grocery store.  Now there’s a supply shortage that directly ties to the pandemic that is starting to affect the space launch industry – oxygen.

It’s common knowledge at this point that liquid oxygen (LOX) is an important tool for combating severe symptoms of Covid-19.  Most patients admitted to the hospital with the virus need oxygen directly pumped into the lungs, usually supplied by LOX suppliers such as AirGas or other commercial gas companies.  Oxygen is also used in high quantities in a completely different application – rocket engines.

UT Video discussing rocketry and the components that go into it.

Chilled oxygen is a necessary propellant chemical for all the leading launch firms, including SpaceX, Virgin Orbit, and ULA.  But it’s becoming harder and harder to obtain the liquid form of the most abundant element in the Earth’s crust.  That’s in no small part because the same process used to create oxygen for rocket fuel can also create oxygen used for Covid patients.  And as Richard Craig, the vice president of technical and regulatory affairs for the Compressed Gas Association, put it: “People come first.”

Even avid space exploration fans wouldn’t disagree with that logic. But the spike in Covid cases over the summer is starting to tax the supply chain for oxygen.  It got to the point that both Gwynne Shotwell, SpaceX’s President, and Elon Musk, its CEO, spoke out about the potential impact a lack of oxygen could have on their flight schedule. Shotwell went so far as to directly ask conference-goers at the 36th Space Symposium to “send [her] an email” if they happen to have any liquid oxygen to spare.

Want to learn the process that is saving so many lives? Here’s how to make small amounts of liquid oxygen.
Credit – NileRed YouTube Channel

She will be hard-pressed to find any in the home state of some of SpaceX’s launches. Florida is one of the hardest-hit states in the current resurgence of the pandemic.  LOX normally isn’t transported over far distances – most is created about 200-300 miles from where it is distributed. It is possible to transport the liquid further. However, another confounding factor impacts the intricate LOX supply chain – truck drivers.

LOX is highly flammable and explosive, so drivers that ferry it between production and consumption sites such as rocket pads have to be even more highly trained than a standard commercial truck driver.  Right now, there is a shortage of commercial truckers of all stripes and a particular shortage of those qualified to haul liquid oxygen.  While some suppliers are, in fact, able to ship oxygen supplies farther than their usual customer base, that takes up valuable time from the truckers who would otherwise be able to deliver it to closer locations.

LOX tanker truck being loaded up in the US. WARNING – LOUD
Credit – silverado 15 YouTube Channel

Those drivers aren’t only responsible for delivering oxygen, though.  Other components for rocket launches, such as liquid nitrogen, are also carried by highly qualified drivers.  This causes supply chain restrictions from the other side as well. In fact, NASA had to delay a rocket launch of an Earth-surveillance satellite by a week due to a lack of liquid nitrogen ULA uses to test the rocket before launch. But the liquid nitrogen was itself a casualty of the oxygen shortage, according to a statement from NASA: “Current pandemic demands for medical liquid oxygen have impacted the delivery of the needed liquid nitrogen supply to Vandenberg.”

This surely will not be the last scheduling casualty of this growing supply chain problem.  SpaceX hopes to surpass their total of 26 launches from last year and are well on their way to doing so.  But their timeline, and all other launch providers timeline, might be impacted by this supply chain disruption.  This is just another reason to hope for a swift end to the pandemic for space exploration enthusiasts.

Learn More:
LA Times – SpaceX sees launch risk from low oxygen supply amid pandemic
Futurism – SPACEX DOESN’T HAVE ENOUGH ROCKET FUEL BECAUSE COVID PATIENTS NEED IT TO BREATHE
The Verge – COVID surge causes liquid oxygen problems for SpaceX, water utilities
NASA – NASA and United Launch Alliance Review Landsat 9 Launch Date

Lead Image:
A Falcon 9 lifts off from Kennedy Space Center Last Year.
Credit – Associated Press

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What is normal weather?

One doesn’t spend much time learning about climatology before coming across a marvelous sound bite: “Climate is what you expect, weather is what you get.” The catch is it’s not clear how to measure what you expect. We’re a lot better at measuring weather.

The whole topic of measuring expectations deserves its own web page, as does the problem that we humans are pretty terrible at remembering weather, even extreme weather, and sometimes even recognizing extreme weather.

One way we define “normal” is that every ten years climatologists collect and average the previous thirty years of weather data, then release that as the “new normals.” While that has a lot of shortcomings, and some are mentioned below, it all works out pretty well when comparing the “current normals” to the “current weather.” However, when new normals are released, and are different than the old normals, confusion reigns for a while until the new normals get accepted. It’s natural for people to compare the old with the new, but it’s not as simple as it sounds. It may not even be a good idea.

What does it mean to compare our “old” normals from 1981-2010 to the “new” normals from 1991-2020? This table helps show a fundamental problem:

Decade	old normal	new normal	Effect on comparison
1981-1990	Included		Removed
1991-2000	Included	Included	None
2001-2010	Included	Included	None
2011-2020		Included	Added

So when we compare these two 30 year periods, we’re really just comparing the decade that started 40 years ago with the decade that started 10 years ago. While we can justify saying things like “over the last 30 years,” that implies looking at a trend that covers a longer period. While that’s often valid, it’s not why we have 30 year normals. Perhaps it makes sense to compare the most recent decade with the one that started 40 years ago, but gee, that’s not comparing two 30 year periods.

I conclude that a 30 year normal period is best used to compare to the weather we’ll have over the next ten years.

Comparing the old and normals at Mt Washington, New Hampshire

Mt Washington in New Hampshire’s White mountains is an interesting place. The important thing for us is that it is the tallest mountain in the northeast, several storm tracks pass near it, and it has a weather observatory on top. It is reachable by foot trails, a cog railway, and an automobile road. The last also sets aside separate days of racing for runners, bicyclists, and automobiles. All entrants are crazy.

It is claimed that Mt. Washington has the world’s worst weather, in part because of recording a surface wind of 231 mph (372) on April 12, 1934. That was a global record until broken by an automated weather station in a typhoon near Australia in 1996. While “the world’s worst weather” has a bit or hype, suffice it to say you can park at Pinkham Notch on a fine fall day, take a 7.4 mile (11.9 km) hiking trail to the peak, and die of exposure above tree line before reaching the top.

Like I said, the release of new normals naturally invites a comparison to the old normals, and that’s what the folks at the Mount Washington Observatory did. They teamed up with NH State Climatologist Mary Stampone and put on the webinar Science in the Mountains: The New Normal: Understanding the Newly Released 1991-2020 Climate Normals.

If you have time, it’s worth watching. Dr. Stampone describes some of the trends around the state and refers to the very long and useful weather record from Concord NH (KCON). They look at the data from atop Mt. Washington (6288′, 1916 m) above sea level and arguably home of the world’s worst weather, the Pinkham Notch trailhead (2025′, 617 m) and home to much more benign weather), and a long time NWS Co-op site in North Conway (522′, 159 m) that is operated by people tied to MWO.

I was very pleased to see, and not very surprised, that the North Conway site had much more warming than the others, but that’s a topic for another web page. So are site locations. The North Conway site has had three moves, but apparently all three are close together. The Concord site is currently at the airport which certainly was not the case early on because there were no airports. I haven’t bothered to hunt down the “metadata” for KCON, I don’t think the changes are very significant.

During the presentation, I raised the issue about the comparison being really the first and last decades.

A few days later I wrote Email to them pointing out more problems with their comparison of 30 year intervals. The most significant one is that while there was mention of increased tropical system activity in 2011-2020, there was no mention of the effect of removing the 1981-1990 activity, so they offered no comparison between the two decades. I remedied that and went into much more detail in my Email.

Ultimately, I received no replies. That was not a surprise, as I asked no questions. The real test will be to see what people say in any future comparison of normals.

Email about the presentation

Date: Thu, 12 Aug 2021 13:17:16 -0400
Subject: More comments on “The New Normal: Understanding the Newly Released
1991-2020 Climate Normals”
From: Ric Werme
To: education@mountwashington.org, Mary Stampone

Hi,

I have a couple followup notes about the recent presentation on the 1981-2010 vs 1991-2020 “normals.”

Comparing normal periods

As I noted during the presentation, the comparison of the two periods is really the comparison of 1981-1990 and 2011-2020. I am extremely disappointed that I was the one to note that, but it does give me confidence that a retired software engineer can have a decent understanding of climatology.

I heard a couple of references to Hurricane/Superstorm/extratropical Sandy regarding the higher October rainfall between the normals. That bothered me a lot at the time. Besides the forecasting and procedural issues with Sandy, a blocking high helped push Sandy westward, ultimately bringing upto 36″ of wet snow to West Virgina and North Carolina.

Some storm summaries have rainfall maps that don’t even show NH! E.g. this retrospective:

Track and precipitation from Superstorm Sandy

However, my Davis VP weather station in Boscawen saw rain in that period:

mysql> select dt, lo_temp, hi_temp, rain from daily where dt >= ‘2012-10-28’ and dt <= '2012-11-1'; +------------+---------+---------+------+ | dt | lo_temp | hi_temp | rain | +------------+---------+---------+------+ | 2012-10-28 | 47.4 | 55.7 | 0.00 | | 2012-10-29 | 51.0 | 60.4 | 1.10 | | 2012-10-30 | 52.2 | 67.4 | 0.97 | | 2012-10-31 | 46.8 | 56.7 | 0.02 | | 2012-11-01 | 42.9 | 52.9 | 0.00 | +------------+---------+---------+------+

www.mountwashington.org/uploads/forms/2012/10.pdf does report 5.76″ from the event, partially estimated due to high winds on the 29th.

The rain we got may have been from an extratropical feeder band being forced over the blocking high:

Wind speed (left), precipitation intensity (right) on 30 Oct.

So, I guess “Superstorm Sandy” counts for skewing the average, but let’s note it was one weird storm and not indicative of a trend. Overall, I think the emphasis should be on nor’easters instead of tropical systems, as we have a lot more nor’easters and they impact a much larger area than the typical tropical cyclone.

Sticking with tropical storms a bit longer, some important ones for us in 2011-2020 include Irene, Isaias, and Zeta. Wikipdia’s List of New England hurricanes lists twelve storms for that period.

There was no reference in the presentation to the the impact of losing the tropical storms of 1981-1990. That is just as important as those we gained in 2011-2020! The former period was during a negative phase AMO [Atlantic Multidecadal Oscillation]. Many people, starting with Bill Gray and his thermohaline circulation studies, note that there are fewer Atlantic tropical systems during the negative phase than during the positive phase. We entered the current positive phase in 1995 – a very busy tropical storm year. We are likely close to a flip back to the next negative phase. That may come with a repeat of our 1950s hurricanes. If so, I’m sure they’ll be blamed on climate change and driving SUVs instead of history.

What did we lose from 1981-1990? That Wikipedia page lists only one storm, Hurricane Gloria in 1985. I was pretty close to it in Milford NH. Rain, blown down tree, lost power. The two nor’easters 7 1/2 years before were much more memorable.

My second note is much briefer

It’s my understanding that the 30-year climate normals are meant to be used to compare current conditions to “normal” weather. Given the pitfalls apparent in this presentation, I think that is about the only thing they are good for.

Of course, it’s important to look at long term climatology, and that’s one of the great things about KCON’s long record. It’s also important to realize that a 30 year period is actually the worst length when there are effects from the approximately 60 year cycles in the AMO and PDO [Pacific Decadal Oscillation]. Longer cycles like one and two century solar-related cycles also need “respect” but are too long to compare against non-cyclic things like anthropogenic effects.

And then there’s the 1930s. Dust Bowl, [Big Wind of 1934], Hurricanes of 1935 and 1938, February 1934 (and repeated in February 2015 – record cold in Portland ME and KCON, and record warmth in Portland OR). It’s no wonder that many longish term comparisons start in 1950!

  -Ric Werme

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