Posted by Dee Norris
Can you figure out what happened at Mohonk Lake, NY?
Get out your slip-sticks and put on your thinking caps, gentle readers. We need to solve the mystery of the temperature record at at Mohonk Lake NY.
On Monday, the New York Times had this to say about the temperature record at Mohonk Lake:
The record shows that on this ridge in the Shawangunk Mountains, about 20 miles south of the better-known Catskills, the average annual temperature has risen 2.7 degrees in 112 years. Of the top 10 warmest years in that time, 7 have come since 1990.
Now I just happen to live in the Catskills (the Shangra-La of New York State, IMBO) and a 2.7 degree (I am assuming F, not C) increase sounded pretty high for the ‘Gunks’ so I turned to this handy tool at www.CO2Science.org for a quick look-see at the USHCN data for the Mohonk Lake (41.77.N, 74.16W; 379m) site. Here is what I found:
Since I live in the general area, I have previously used the data from a site in nearby Maryland, NY (42.52N, 74.97W; 363m) in a local lecture. I was sure I remembered that the station in Maryland had not exhibited a trend like this. Double checking the ol’grey matter, I got this graph:
Both sites are at the same altitude and in the same general vicinity. I know that climate change can’t be that localized, so it has to be something else.
I hope to get down to Mohonk Lake this weekend if possible for a closer inspection, but in the meantime, here is an opportunity for all the climate sleuths out there to take a shot at solving The Mystery at Mohonk Lake.
UPDATE: The Mystery Deepens
In a converstion today with Paul Huth at Mohonk Preserve, I was assured that the station did not have the latest electronic MMTS measurement system and that they still used the original system installed in 1896, but an inquiry at NCDC provided the following equipment:
An appointment for a site inspection has been set up for the middle of next week.
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My wife and I were up there a couple of years ago for a weekend and it looked like they have been adding on to the complex. My guess is that the station is now too close to a heat source and is being affected, where it was probably out in the open before.
Lets see a picture of the location of the temperature recording location. That might tell the story.
This is the problem when using single station records, now I am not saying the adjustments at GISS are right what I am saying is the overlapping regional adjustments will fix this unless…drum roll
The continous record from neigbouring stations are incomplete and the station is weighted as a rural unlit site.
This definitely at first blush looks like a station specific issue and begs the question you are workign hard to solve “how many of these are there?”
I went to GoogleEarth to check the area out. The place is not available in high res. However, we can see zones of significantly browner tone, between due west and south-west of Mohonk lake. Is that darker area fresh tree cutting areas or are they rocky mountaintops?
If these are tree cutting areas, the area is significantly larger that the lake and ridge area itself (between one and two order of magnitude), located quite close, with spacing between the two being only a fraction of the characteristic dimension of the brown area itself. Could the wind heated from this darker ground cover blowing from that direction reach the lake at an artificially high temperature?
It would be interesting to subtract the temperatures at one site from the other (perhaps after a short running-average), to see if there were any sudden major changes in the temperature reading at Mohonk Lake NY at specific times.
If there were only a few major “steps” in temp readings, then the apparent rising temperatures may have been due to new buildings near. OTOH, if it was mostly a gradual divergence in temperatures, then it could simply be an Urban Heat Island effect.
I’ve said it before, one station should NOT adjust another, period. That’s just making up data. It could be that the local climate really is that different from one site to another just a couple miles apart. I live on Whidbey Island in Washington State. My dad lived on the west side facing the sound, and I live more on the east side over the inner sound. It would often be raining at his place and never rain at mine, about 10 miles away. He would receive direct winds from the sound, the winds I received were diluted and diverted much of the time, so yes, his local climate could be pretty different from mine.
Dee, are there other stations within 50 miles? Might give a better idea of the regional trend, but I’d say it’s more likely a bias due to siting, like others have pointed out.
Reply – Oh yes… And they all are available for your investigation here: USHCN Trend Calculations — New York
Here is a map of the NYS sites to chose from: NYS Station Siting Map
I have no idea what I am going to find there, so your analysis is a good as mine. – Dee Norris
Not only that, but homogenization covers up and disguises the gross errors shown up by the site violations exposed by the Rev.
This definitely at first blush looks like a station specific issue and begs the question you are working hard to solve “how many of these are there?”
Over six out of seven so far. With well over seven out of ten having severe problems. In light of that, it would be surprising if there were not site violations.
Re. the graph: Interesting that the slope from 1896 – 1950 appears to be greater than that of 1950 to date.
Reply – I think that something happened around 1955 or so. – Dee Norris
My money is on a new road next to the temperature station, followed by a new car park, followed by an air-con outlet plus a few minor adjustments.
“As he has done most days for the last 34 years, around 4 p.m. Mr. Huth scrambled up the conglomerate outcropping in the shadow of Mohonk House”
“Through about 100 purchases, Mohonk grew from 280 acres in 1869 to 7,500 acres a century later. In the 1960’s, the family set aside more than 5,000 acres as a forever-wild preserve, leaving more than 2,000 acres for the resort.
The seven-story hotel, with 261 guestrooms and 138 working fireplaces, was declared a National Historic Landmark in 1986. It spreads out with a number of stone and clapboard additions”
” they have since tried to inject new life, investing in renovations to shed dowdiness, installing air-conditioning and upgrading the food with more imaginative dishes and high-profile chefs. In 2001, they spent $3 million on a new skating rink in a dramatic open-air pavilion with a 39-foot-tall fireplace at one end. ”
http://travel.nytimes.com/2006/02/24/travel/24mohonk.html
Air conditioners? Fireplaces? New rooms? Golf course expansion?
Ahhh. The key is right here:
“But years ago Mohonk went from being a summer getaway to a year-round establishment”
Bingo!!!!!!!!!
USHCN shows Mohonk site as existing from 1948 (here’s their graph):
http://cdiac.ornl.gov/cgi-bin/broker?id=305426&_PROGRAM=prog.gplot_meanclim_yr.sas&_SERVICE=default¶m=TAVE&minyear=1948&maxyear=2005
so I assume that data for years prior to 1948 is a filenet fudge factor.
Hope you make it to Mohonk and can get some photos of the site that might shed some light on the warming of the past ten years.
From your graph it looks like the two stations diverged around 1946. As Anthony says, “it looks like a step function”.
The temperature before ’46 was lower at Mohonk Lake than the other station. Afterwards the station reads higher. What happened back in the 40th? New buildings, parking lots, forested area cut down to make room for new development?
There is also a “step function” in the mid 20th. Perhaps development again.
My bet is that construction and expansion makes the two sites different. Nothing else.
Records from nearby stations at Poughkeepsie (urbanish) and Walden (rural) are basically flat. Local effects are suspect for Mohonk lake.
What ever change was made to the weather station location, happened in 1953. Thats my expert opinion 🙂 I think its an air-con vent or something else that has a stable temperature output, like a generator exhaust.
I spent a weekend at Mohonk Mountain House at an event hosted by a New Jersey group. They held it there because it was so much better than new Jersey. Neat, neat, place.
Have you seen http://www.nytimes.com/2008/09/16/science/earth/16moho.html?ref=nyregion ? From the article:
They also have records of flowering times and other events. The Times has a graphic that shows very flat temps from the 1930s to 1980 but a big spiky climb after that. Looks like yours with an extra year. It would be worth checking to see what their raw data looks like before any USHCN adjustments.
Ah well, what a great excuse for a visit. If I had time I might’ve invited myself along. 🙂
Ok, so I chose the two closest places to Mohonk, Walden and Poughkeepsie. The date range is 1925-2006. 1925 was the oldest common starting point for all three sites, not trying to cherry-pick, but wanted a common time frame for all three.
Here are the graphs:
Monhonk Lake 1925-2006
Poughkeepsie 1925-2006
Walden 1925-2006
[REPLY – Graphs not coming through. ~ Evan]
Ugh, guess img tags don’t work. Here are the links
http://jalberts.net/images/graphaMohonk1925-2006.png
http://jalberts.net/images/graphaPough1925-2006.png
http://jalberts.net/images/graphaWalden1925-2006.png
Doesn’t seem to be much trend at all.
Have those sites been surveyed?
Quick question commenters: did you notice that the source article source articleaddresses many of the usual culprits re: local mesaurement bias? I’m thinking that is why Dee is asking us to “put on our thinking caps”.
The sizzle in the article is the quality of the site and the observations:
<blockquote cite =”If the procedure seems old-fashioned, that is just as it is intended. The temperatures that Mr. Huth recorded that day were the 41,152nd daily readings at this station, each taken exactly the same way. “Sometimes it feels like I’ve done most of them myself,” said Mr. Huth, who is one of only five people to have served as official weather observer at this station since the first reading was taken on Jan. 1, 1896.”
That extremely limited number of observers greatly enhances the reliability, and therefore the value, of the data. Other weather stations have operated longer, but few match Mohonk’s consistency and reliability. “The quality of their observations is second to none on a number of counts,” said Raymond G. O’Keefe, a meteorologist at the National Weather Service office in Albany. “They’re very precise, they keep great records and they’ve done it for a very long time.”
Mohonk’s data stands apart from that of most other cooperative weather observers in other respects as well. The station has never been moved, and the resort, along with the area immediately surrounding the box, has hardly changed over time. Rain and snow are measured in the original brass rain gauge issued in 1896 by what was then known as the United States Weather Bureau. Mr. Huth also checks the temperature and pH of Mohonk Lake daily, and he measures the level of the lake according to its distance from the top of an iron bar that was bolted to the Shawangunk conglomerate in 1896. ”
I’m going to keep an open mind and see what Dee comes back with. If the record really is as pristine as reported then it makes for quite a puzzle – especially when considered in the context of the nearby Maryland site.
It would be worth checking to see what their raw data looks like before any USHCN adjustments.
Also, the 1980s (aside from being a positive PDO cycle) are when the MMTS switchover began, causing a huge number of CRN4 site violations.
And yes, the “MMTS adjustment” is positive. (As well as SHAP.)
Jeff Alberts,
Strangely, when I went to the link Dee provided and punched up Poughkeepsie for 1828-2006, I got a very different graph — one that has a 2 degree or so uptick? Where did you get your graph for Poughkeepsie?
Eric
Jeff, never mind. I reread your post and see that you did a 1925-2006 comparison. Poughkeepsie does have a noticable uptrend for the 1828-2006 data, but you’re right that it has a flat to slight downtrend from 1925-2006. I think we need to be careful about cherry picking, but I see what you did.
It looks like the Mohonk data is 1896-2006. With that time interval, Poughkeepsie also shows an upward trend, albeit very slight.
I think this underscores the challenges of picking out a trend from the data (assuming the data is good). It is too easy to identify a “trend,” depending on the timeframe chosen.
Eric
I would counsel people to check here: http://www.nytimes.com/2008/09/16/science/earth/16moho.html?scp=1&sq=mohonk&st=cse The coolest temp in the graph published by the Times shows a mean below 32 degrees fahrenheit, whereas the graph provided here by Dee never goes below a mean of 41 degrees.
The Times graph, provided by Ben Cook of GISS, shows a swing of nearly 20 degrees in MEAN values! He answered an e-mail query I sent him about this, but did not answer the question about the value below freezing near the turn of the last century. I sent him a follow-up and I’m still waiting.
As for the surprising heating showed at this station, it doesn’t appear to be a very pristine measuring environment, now that we put it under pressure…
Puzzling?
They went from a summer-only resort to all-year resort which means all those wood burning fireplaces exhausted the heat somewhere.
And the smoke probably acted as cloud cover keeping it warmer near the wweather station.
And they added air conditioning … meaning more heat nearby from the exhaust vents.
No surprise. The land use changed considerably.
“Mr. Huth opened the weather station, a louvered box about the size of a suitcase, and leaned in.”
Wonder about the condition or upkeep of the ‘louvered box’, or for that matter the potential for canopy changes around the box (?).
Evan, this station switched to MMTS in 1991, but the Stevenson Screen has been retained. The question then is: which one are you using?
My guess is that like most MMTS setups, it becomes the primary, and the Stevenson Screen becomes the backup. Though, they may do both. The other question is: “when there is significant snow or inclement weather, whcih station do you use?
My guess is that the MMTS will suffer from all the usual placement biases we’ve seen, especially building proximity.