Updated – Calling All Climate Sleuths

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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September 17, 2008 7:38 am

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.

September 17, 2008 7:48 am

Lets see a picture of the location of the temperature recording location. That might tell the story.

September 17, 2008 8:05 am

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?”

JFA in Montreal
September 17, 2008 8:23 am

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?

Chris H
September 17, 2008 8:32 am

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.

Jeff Alberts
September 17, 2008 8:33 am

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

September 17, 2008 8:38 am

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

September 17, 2008 8:39 am

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.

September 17, 2008 8:49 am

“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. ”
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”

Leon Brozyna
September 17, 2008 8:49 am

USHCN shows Mohonk site as existing from 1948 (here’s their graph):
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.

D. Quist
September 17, 2008 9:27 am

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.

September 17, 2008 9:44 am

Records from nearby stations at Poughkeepsie (urbanish) and Walden (rural) are basically flat. Local effects are suspect for Mohonk lake.

September 17, 2008 10:02 am

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.

September 17, 2008 10:17 am

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:

Every day for the last 112 years, people have trekked up the same gray outcropping to dutifully record temperatures and weather conditions. In the process, they have compiled a remarkable data collection that has become a climatological treasure chest.
The problems that often haunt other weather records — the station is moved, buildings are constructed nearby or observers record data inconsistently — have not arisen here because so much of this place has been frozen in time. The weather has been taken in exactly the same place, in precisely the same way, by just a handful of the same dedicated people since Grover Cleveland was president.

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. 🙂

Jeff Alberts
September 17, 2008 10:19 am

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]

September 17, 2008 10:23 am

Doesn’t seem to be much trend at all.
Have those sites been surveyed?

Jim Burnham
September 17, 2008 10:25 am

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.

September 17, 2008 10:28 am

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.)

Eric Anderson
September 17, 2008 10:38 am

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 Anderson
September 17, 2008 10:46 am

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.

September 17, 2008 10:58 am

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…

September 17, 2008 10:59 am

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.

Steve Geiger
September 17, 2008 10:59 am

“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 (?).

September 17, 2008 11:06 am

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.

Scott Covert
September 17, 2008 11:12 am

Does this site have more cloud cover? The first graph seems to have a larger ratio of warm nights.
Warm nights, that seems to be a recurring bias in most of the UHI Effect.
Something is bottling up the heat at night.

September 17, 2008 11:20 am

That’s not a typical site by any means. Look at the Terrain map on Google Maps. The lake is about 800 feet up on a mountain.

Ron McCarley
September 17, 2008 11:50 am

Has Hansen ever stayed there?

Jeff Alberts
September 17, 2008 11:51 am

Eric Anderson,
Right, I chose 1925 because one of the three, Walden, I think, only had data going back that far. So to compare apples to apples, I chose that date range for all three.

September 17, 2008 11:57 am

Something that changed about 50 years ago: Fire suppression (ie, “Smokey the Bear”). The region’s forests are pine barrens and chestnut oak, which are dependent upon regular fire… and they’ve been burning regularly for 9,000 years. The result tends to be grassy or herb ground cover with tall-limbed large trees, and often it’s easy to walk (or drive a horse-drawn carriage) through. That’s not what recent photos show.

Fred . . .
September 17, 2008 12:24 pm

“Ron McCarley (11:50:37) :
Has Hansen ever stayed there?”
Don’t know, but Gore stayed at the closest holiday Inn and it made him real smart.

September 17, 2008 1:00 pm

Using MS Paint I overlayed one over the other and noticed that they are scaled differently. Mohonk Lake x scale is 41-51 degrees, while Maryland is 40-49 degrees.
Once I approximated the scales it looks like they match pretty well up to about 1942/3 (except for the early 1920s where Mohonk gets a big peak and trough, where Maryland doesn’t). Then Mohonk seems to add 2-3 degrees on all subsequent readings. The movements roughly match, just Mohonk is always up on the peaks and troughs.
What could add 2/3 degrees on every subsequent reading virtually over night?
Anthony – great job.
Any chance of overlaying the 2 graphs and scaling on the web page so all
can see what I’m on about?
Reply – The data for all the sites discussed here is available at the CO2Science.org’s USHCN Trend Calculations — New York. Once you plot the site and the time period, a link to the data will appear below the data on the trend line. Just pop the data in Excel for a quick comparison. – Dee Norris

September 17, 2008 1:21 pm

Here is a link to a page comparing Mohonk Lake with Poughkeepsie and Falls Village. Mohonk and Falls Village are very similar until the warming at Mohonk in the mid-nineties. This data is from the NOAA GHCN database.
See also the comparison of New York City with its rural neighbors, showing a case of urban warming.

September 17, 2008 1:26 pm

Mohonk suffers from UHI as NYC metro went from several million to 20 million in the past century, along with more recent siting/instrument changes. Look at the Walden graph – there is a problem with the 1959-1970 period. Looks like they entered a mini ice age!

September 17, 2008 2:00 pm

The article mentions that the observers have to trek up the gray granite rock outcropping. This gived me the impression that the weather station is far enough from the buildings/parking lots to avoid their affects.
Also, if the weather station is located on or very near granite, how would this affect the observations?

September 17, 2008 2:03 pm

Scott Covert (11:12:55) :

Does this site have more cloud cover? The first graph seems to have a larger ratio of warm nights.
Warm nights, that seems to be a recurring bias in most of the UHI Effect.
Something is bottling up the heat at night.

It is a hilly area, so it’s less prone to cold lows due to radiational cooling. Chilled air in the hills flow down to the valleys where the spectacular radiational cooling reports come from. Also, the inversion that forms in valleys blocks nighttime winds, so there can be much better mixing 100′ above the valley.
So it may be not so much bottling up the warm air as not trapping the cold air. I’m assuming the thermometers are above where radiational cooling has a substantial effect. If not, it could be that the combustion air used during the winter uses up the radiationally cooled air and the lake area may not have as severe radiational cooling as when they closed up during the winter.
Were they really closed completely in the winter? I was there in March. I think. Snowfree at the time.
novoburgo (13:26:20) :

Mohonk suffers from UHI as NYC metro went from several million to 20 million in the past century, along with more recent siting/instrument changes.

I wouldn’t expect NYC UHI to have much impact. Winds in the northeast are usually either NW or SW. SE to NE winds generally mean coastal storms Mohonk is due north of NYC. The Catskills were quite rural the last time I was in the area.
Reply – The Gunks are not part of the Catskills and MetroNorth, a commuter rail out of NYC, reaches almost that far north in near by Orange County where there has been a boom in McMansions turning the area into a bedroom community for NYC. Similar development projects have been thwarted in the Gunks. – Dee Norris

Pete Mc
September 17, 2008 2:22 pm

Normally a lurker but can’t resist a challenge!
Given that the USHCN Trend Calculations are correct, I dug up the closest 4 temperature histories to Mohonk Lake that date past 1896. Those were Port Jervis, Poughkeepsie, Maryland and Troy… all in the general area of Mohonk. From those, I computed the temperature anomaly from each stations average. From that I computed the difference between Mohonk’s anomaly and the other station’s anomalies. I then color coded them and started looking for odd stuff to pop up. Here’s what I have:
1: The temperature data for Maryland matches Mohonk EXACTLY from 1898 to 1903 and 1921 to 1924.
2: The Mohonk temperature anomaly was exceptionally low compared to other stations in the area between 1898 and 1901. Excluding the duplicate Maryland data, Mohonk’s average anomaly was over 3 degrees lower than everything else in the area for this period. 1920 and 1923 were also exceptionally cool years for Mohonk compared to other stations. 1924 and 1925 were exceptionally warm compared to the surrounding area.
3: From 1896 to 1951 (First half of data), Mohonk’s anomaly was lower than the surrounding stations 34 times and higher 22 times while the average anomaly was .46 degrees lower in Mohonk than in the surrounding stations. From 1952 to 2005, Mohonk’s anomaly was lower than the surrounding stations 14 times and higher 40 times while the average anomaly was .48 degrees higher in Mohonk than in the surrounding stations.
4: Pinning down a specific event from the data isn’t quite as easy. 1984 is a suspiciously warm year but this is the only year from 1950 to 1983 where Mohonk’s anomaly was higher than all other area anomalies. The one area that sticks out is from 1997 to 2005 when the Mohonk anomaly consistently ran hotter than anything in the surrounding area. This is especially dominant from 1999 where Mohonk was running an anomaly 1.5 to 2 degrees higher than all other stations.
My guess based on the data (provided it is accurate and I analyzed anything meaningful): Mohonk saw a lot of locally cool weather during the first half of the century followed by an influx of tourism in the late 90s. I’d look for something that might have been build or installed in 1997 or 1999.
I should note that this is just 4 stations and all of the stations reported temperature anomalies that weren’t seen by the other stations in the area in various years.

September 17, 2008 2:35 pm

My guess is that they built that lovely hotel or drained the lake 🙂

sammy k
September 17, 2008 3:03 pm

ok i’ll try…given mr watts background, i would guess, based on reading of the article, someone suspects something is wrong with the weather station box or the manually resetting of its components…its interesting nevertheless, how the mohonk’s profess ecological eden while building anthropogenic hotels, spas and research facilities while fighting all other developement that encroaches their resort…

September 17, 2008 3:28 pm

I found a couple of old pictures which may shed some light:
This is the ebay description of the picture
Here is another ebay postcard from 1907:
Heres another from 1918:

Stephen Garland
September 17, 2008 3:49 pm

Has the turbidity of the lake increased due to increased nutrients. If so, the surface waters would be warmer (in summer) and may influence the station. It would be interesting to see the water temperature record for the lake.

Jeff Yeates
September 17, 2008 4:22 pm

Looking at the Mohonk graph, about 1957, 1967 and 1978 there are fairly flat sections with 1968-1970 staying at about 46.5 – did the low/high points on the day/night thermometer get stuck?

September 17, 2008 4:47 pm

Ric (14:03:46), I got to slightly disagree with you. The Newburgh/Poughkeepsie area has changed considerably in the past century and is almost an extension of the greater NY metro area. FYI almost every transiting Low (of which we have a large yearly number) results in a period of S to SE winds in the area. While it’s not a prevailing wind it’s enough to have a small effect throughout the Hudson Valley and surrounding areas.
I personally think most of the rise can be attributed to unmentioned changes at the observation site and no, there isn’t any proof that Henry Hudson set up the Wx station.

September 17, 2008 4:49 pm

Mohonk Lake is no different than the nearby stations. Here is a graph of 4 of the area stations (including Mohonk Lake). The plots are virtually indistinguishable.
REPLY: Alan thank you. Would you be so kind to to cite (with a URL also) the source data used?

September 17, 2008 5:04 pm

Mohonk Mountain House is in New Paltz.
” the motor car started replacing the train and in the early 1950’s, the New York State Thruway was built and brought New Paltz, as Exit 18, fully in touch with the world. ”
1958 was the coldest year. Then it started to warm.
Al those people streaming by on the Thruway couldn’t cause a change .. could it?

Pamela Gray
September 17, 2008 5:19 pm

Wind will go uphill to the top of a mountain. Unless stopped by tree cover. Maybe the canopy changed below the peak? Winds can warm a person (and a thermometer) right up, if the wind is coming from a heat island. I would look below the hotel to see what has been happening surrounding the mountain.

September 17, 2008 5:20 pm

“The Stevenson Screen thermometer. shelter and US Weather Bureau rain gauge have never. been moved from their original locations.”

September 17, 2008 5:53 pm

Well my guess is they build a tennis court around the Stevenson Screen, just like the one at Lake Tahoe. See the Tahoe City post on Anthony Watts Surface Station data base here: http://gallery.surfacestations.org/main.php?g2_itemId=694 What do you think?

September 17, 2008 6:29 pm

Reply to reply of my previous post:
The graphs in the links of my previous two posts are from the NOAA GHCN database. The graphs are created at:
That page provides links to the source data at NOAA (and for data at Hadley).

September 17, 2008 7:17 pm

Well my guess is they build a tennis court around the Stevenson Screen,
Clay or grass? #B^1

Jeff Alberts
September 17, 2008 7:44 pm

Mohonk Lake is no different than the nearby stations. Here is a graph of 4 of the area stations (including Mohonk Lake). The plots are virtually indistinguishable.

Hmm, they look pretty distinguishable to me. The three graphs I posted from the GHCN network all with the same time frame showed the two closest sites (Walden and Poughkeepsie) with a flat to slight downward trend, and Monhonk Lake with an upward trend.
Does it mean anything? Maybe, maybe not. The point is you can’t look at one site and take global or even regional meaning.

September 17, 2008 8:30 pm

Walden and Poughkeepsie:
Walden has a gap in the data – perhaps the station was moved and is therefore not consistent over the long term. See:
NASA data:http://data.giss.nasa.gov/cgi-bin/gistemp/gistemp_station.py?id=425725030070&data_set=0&num_neighbors=1
NOAA data:http://www.appinsys.com/GlobalWarming/climgraph.aspx?pltparms=GHCNT100AJanDecI188020080900110AR42572503007x
The NASA data for Poughkeepsie looks like this:
Poughkeepsie and Mohonk Lake are quite similar if you compare the anomalies:
The fact that 5 of the 6 stations (i.e. not Walden) look very similar indicates there is probably nothing very special about Mohonk Lake in the long-term.

j. connor
September 17, 2008 10:07 pm

Odd how the reporter made it sound as if the weather observer had to trek out to this isolated Stevenson screen, uphill both ways, blah blah… Just like the old days.
It looks to be a mere 40 ish? feet from the office, under the comforting shade of a well established tree.
Then again the picture on that page doesn’t show it’s relation to the long term parking or the green technology visitors center. Or the victorian maze added to the resort in 1998. Or the new 30,000 sq ft spa with a 2000 sq ft green roof garden terrace, heated outdoor mineral pool and of course no mention of the Six hundred tons of quartz conglomerate stone excavated from the site and recycled into stone walls, fireplaces and retaining walls throughout the spa.
Now, I would assume the resort and the preserve are two different entities with enough seperation to avoid contamination of the data from all the new additions, however we have all seen how land use changes can contaminate data from quite a distance. Other than the addition of the Victorian maze in 1998, I found no dates for the other rennovations mentioned above but they sound fairly recent. They also would seem to require quite a bit of clearing of established vegitation for the construction…
In any event I hope the links and the picture of the Stevenson screen help in some way. Enjoy your outing.Odd

September 17, 2008 10:50 pm

Alan Cheetham (20:30:34) says:
nothing very special about Mohonk Lake in the long-term
I downloaded the data in text form from here:
and averaged daily differences for TMAX for available decades up to the present. A small percentage of records are either missing or flagged as inconsistent in the data files and were left out of the calculation. Here’s what I get:
WALDEN – MOHONK (col 3 1973-)
TMAX deg C Average by decade
1919-1928 1.6
1929-1938 2.3
1939-1948 1.8
1949-1958 2.1 2.0
1959-1968 1.9 2.2
1969-1978 1.9 2.2 2.3
1979-1988 1.8 1.5 1.7
1989-1998 1.7 1.8 0.9
1999-2008 0.1 0.7 0.2

Tom in Florida
September 18, 2008 4:22 am

The only way to solve this would be to switch the equipment between the sites and see what that shows. It would either prove or eliminate any equipment or siting issues.

j. connor
September 18, 2008 4:38 am

Aerial photo of the area taken in 1994. Hope it saves the coordinates.

Steve Keohane
September 18, 2008 6:48 am

I was going to guess that something changed about 1990, Anthony’s post mentions it went to MMTS in 1991. I am curious about Dee’s comment re: the tannic acid production, inferring that the area was once forested in oak, probably very old oak, and then replanted in maple. I wonder what the differences in the two types of forests might be. Oaks tend to sprawl out horizontally and maples grow more vertically.
Reply – In a forest where their is competition for sunlight, oaks will be vertical as well and eventually tower over the maples. In an open pasture, both will get pretty wide. – Dee Norris

Pamela Gray
September 18, 2008 7:14 am

Building permits should show construction dates for these various additions and changes. I would check there before going up the mountain.

September 18, 2008 7:58 am

Since the resort is crowded around the lake, waste or cooling-water discharge into it could be a factor since warmed water will float on the surface affecting air temp above it — perhaps more so in the winter (when it’s not frozen).

September 18, 2008 8:29 am

I repeated some of my earlier calculations on the raw data for individual months. The increase at Mohonk Lake relative to nearby Falls Village in recent times is evident year-round, but is most marked in June and July. In these months Mohonk Lake temps have increased nearly 3 deg C relative to the nearby station over the last 20 years.
Note Mohonk is at elevation 380m. Falls Village is at 168m and 38Km away. Over the last decade Mohonk is the warmer in these months.
Falls Village – Mohonk Lake
(diffs in max daily temp, averaged over decades)
June/July only
1909-1918 2.6
1919-1928 2.7
1929-1938 3.2
1939-1948 2.9
1949-1958 3.1
1959-1968 2.7
1969-1978 2.8
1979-1988 2.3
1989-1998 1.8
1999-2008 -0.4

Tom in Florida
September 18, 2008 9:15 am

dipole:”The increase at Mohonk Lake relative to nearby Falls Village in recent times is evident year-round, but is most marked in June and July. In these months Mohonk Lake temps have increased nearly 3 deg C relative to the nearby station over the last 20 years. ”
Seems like the Sun heating the lake water could be the culprit here. However, we have been told the Sun has very little effect on climate which is ridiculous.

September 18, 2008 9:18 am

It’s called local warming. Mohonk has a fever and we must save Mohonk. We need to call Al Gore and then have a big rock concert. Or raise taxes. Or both.

September 18, 2008 10:09 am

FWIW, the Maryland, NY, weather station changed locations several times.
One of those changes occurred in May 1947. The new location was
estimated to be about 1.5 F cooler (annually) than the old location.
That estimate is implied by the USHCN SHAP adjustments for Maryland data.

j. connor
September 18, 2008 10:48 am

Well, no MMTS as of December 21, 2006 according to this article. Also it was a 2.3 deg F increase over 100 years reported at that time.

Scott Finegan
September 18, 2008 10:50 am

Something to check on…
One of the least expensive ways to add air conditioning to an old structure, besides individual ac units is: Chilled water from the lake, which is then warmed.

George Patch
September 18, 2008 11:11 am

Since they have such good records, I wonder what the water temps look like over time? and how that compares to the air temperatures. Maybe the water is hotter causing the air to be hotter? Yeah, I know this is not Yellowstone, but just a thought.

September 18, 2008 5:40 pm

Cooperstown (42.70N,-74.92E) is about 50Km from Mohonk Lake at a similar elevation (366m) and has a similarly long record. According to Google Earth it’s the birthplace of baseball! It’s next to Otsego Lake, also with a big resort-style hotel.
Mohonk shows some recent warming relative to this station, but not as pronounced.
Cooperstown – Mohonk Lake
Diffs of max temp, averaged over decades.
All Months (col 1) June/July (col 2)
1899-1908 -1.2 +0.1
1909-1918 -1.4 -0.8
1919-1928 -1.5 -1.0
1929-1938 +0.1 +0.9
1939-1948 +0.5 +2.1
1949-1958 +0.1 +1.0
1959-1968 +0.3 +1.0
1969-1978 +0.1 +1.0
1979-1988 -0.3 +0.0
1989-1998 -0.8 -0.6
1999-2008 -1.3 -1.5
Reply – Cooperstown is right next to Maryland, NY and has experienced a LOT of growth due to the Baseball Hall of Fame and other attractions. While I have the IR camera here, I hope to get to both Coopertown and Maryland as well as Mohonk and Walden. – Dee Norris

September 19, 2008 2:33 am

Anonymoose gave me an idea.
At the beginning of the interglacial, the world was not a very green place. Over the last 12,000 years it has grown progressively greener, especially with fire suppression in our forests. Now, I understand that since the industrial age, globally, we have lost about 50% of our forests for crops and other land uses. However, most of the warming of the last 30 years has been in the Northern hemisphere where many developing countries are seeing reforestation due to environmental measures.
Deforestation is occurring in the topics and in the southern hemisphere, and temperatures have not risen as much there.
Obviously, a greener planet or hemisphere has a much different albedo than a not so green planet, and add to this the heat absorbtion in urban areas, it is clear that less sunlight is being reflected back to space and we are absorbing more heat from the sun than 5-10,000 years BP.
Also, the increased mass of the trees seems likely to absorb more heat and reduce the rate of heat loss from the surface, especially in the evening when it is pumping out CO2.
Maybe this is why Hansen is suggesting using trees as fuel (obviously he does not want to say trees are causing global warming, since too much has been bet on CO2).
It might be that trees are causing the warming we have had, or at least contributing, and thats not necessarily a bad thing. I still remember the blizzard of 78. Brrrrrr.

Steve Keohane
September 19, 2008 4:04 am

Dee-Of all the trees I climbed in Mass, prior to 1965, I never saw a sprawling maple. Tapped a lot for syrup though.
Reply – I have both forested and pasture land on my property. Maples will sprawl to some degree if there is no competition for sunlight as in the pasture. – Dee Norris

Pete Mc
September 19, 2008 7:06 am

Is there a single public source for all the USHCN data? This “challenge” was interesting but I spent most of the time grabbing data for each individual site and then converting it into something Excel could use. I’d like to tinker w/ this in my spare time but I have no interest in pulling the data from each individual site a piece at a time.

September 19, 2008 9:14 am

Pete Mc
The hcn_doe_mean_data.Z file at
includes USHCN “raw” temp data, as well
as with two “adjustments”, time of observation,
and station change.
See the readme.txt file for format descriptions,
station.inventory.Z for station number cross
reference, and station.history.Z for station
change info.

Pete Mc
September 19, 2008 9:43 am

Thanks, Jerry

September 19, 2008 10:54 am

I understand that since the industrial age, globally, we have lost about 50% of our forests for crops and other land uses.

Oh, that’s a complicated issue.
Most of the U.S. (maybe most of the Americas…and Europe) were savanna — grassland with tall or scattered trees before European exploration.
Over 90% of the native americans died from 1492-1550, so the savanna-required burning was greatly reduced. Buffalo population boomed and they moved into the eastern savanna. Some of the woodland along the Atlantic east coast became overgrown into forest; the Pilgrims arrived in a “virgin” forest which may have been 100 years old. Much of what we now call “old growth forest” was cut when railroads and industrialized sawmills reached them in the early 1900s. However, North America and Europe now have more forest than in the early 20th century, which was more forest than in 1492.

Dave the Denier
September 19, 2008 3:23 pm

The fact that one person is responsible for taking the readings at the remote station may be a glaring weakness — not the claimed strength — in the process.
It sounds like quite the uphill climb. No disrespect intended, but what if the record-keeper did not make it up to the remote station everyday, yet “estimated” what the readings may have been for the missed day(s). In the summer, especially (as it appears that the reported rise is concentrated in the summer months), the readings are vulnerable to the following scenario:
Instrument reset on Day Zero.
Day 1 has a unseasonably high temp of 90 degrees and a low of 70 degrees on a clear day/night. On Day 2, 4:00pm rolls around, and for whatever reason the reading is not made (busy or too hot to climb — the solitary reader is much older than he used to be). On Day 2, it “felt” just as warm or warmer than Day 1, so when the instrument is read on Day 3, the high was shown as 90 degrees — even though Day 2 may have only been 82 degrees with higher humidity than Day 1 — Day 2 is officially recorded at an estimated 90 degrees, even though the true temperature reading was 82 degrees. If this scenario occurred more often as the years ensued, an upward trend in Max Temp would occur.
I am not calling anyone a liar or cheat — just pointing out that all humans have weaknesses — and the possibility I described above COULD be one many factors (other than AGW) affecting the instrument readings.

j. connor
September 19, 2008 4:06 pm

“It sounds like quite the uphill climb. No disrespect intended, but what if the record-keeper did not make it up to the remote station everyday, yet “estimated” what the readings may have been for the missed day(s). In the summer, especially (as it appears that the reported rise is concentrated in the summer months), the readings are vulnerable to the following scenario:”
Not to worry, look behind the man at the Stevenson screen in the second picture. Notice the window in the office building? Or is it a house?

Dave the Denier
September 19, 2008 6:27 pm

I do not wish to appear argumentative with commenter, ‘j.connor’. I only know what I read in the NYT article:
“Every day for the last 112 years, people have trekked up the same gray outcropping to dutifully record temperatures and weather conditions.”
As for the referenced picture, it is unlabeled. I do see the building right beside the weather station. Hmm. I wonder when the building was constructed? Assuming the picture is of the Mohonk weather station, the building could be a factor in the temperature rise. Again, does anyone know when it was erected?
Also, the NYT article states the following:
“The station has never been moved, and the resort, along with the area immediately surrounding the box, has hardly changed over time.”
Personally, I think the Mohonk folks and the NYT have jumped-the-gun carelessly (an all too common trait among the AGWers). Until, the above quoted “hardly changed” is defined and extensively researched and photographed with the survey released publicly, this is, at best, a highly unscientific, anecdotal account of warming.
Finally, is it just me, or does the actual reported warming seem confined to only the Summer Max Temp records?

September 19, 2008 7:41 pm

Dave the Denier says:
“does the actual reported warming seem confined to only the Summer Max Temp records?”
There is warming year round in the max temp records over the last couple of decades, but it is certainly more pronounced in the summer, and seems to peak in June/July, at least compared to nearby Falls Village. There is no comparable (relative) warming in the min temp record.
Falls Village is hi-res on Google Earth and still looks fairly rural. For recent 5 year averages the difference FV – ML looks like this (deg C, June/July only, max temp):
1979-1983 2.9
1984-1988 1.6
1989-1993 1.9
1994-1998 1.7
1999-2003 0.3
2004-2008 -1.4
So over 4C relative shift! Just eyeballing the numbers, there seems to be quite a (relative) jump around the beginning of August 2004.

September 20, 2008 12:42 am

Thanks for the link, j. connor: http://www.mohonkpreserve.org/index.php?weatherdata#warmtrend
That looks like wood chips on the ground. Someone’s going to have a fun survey. Incidentally, I’m not finding when wood chippers became common; it was only a few decades ago. Wood chips were not common mulch before wood chippers. And due to the material, I suspect bark chips have different biological and thermal characteristics.

September 20, 2008 12:49 am

Aren’t Stevenson screen doors supposed to be on the north side? That means the building in that photo is just north of the screen. I think low-angle winter sunlight heats the ground south of buildings more than happens away from buildings (based on observation; I suspect reflection and radiation from warmed wall are both factors).

j. connor
September 20, 2008 3:05 pm

No worries Dave the Denier

j. connor
September 20, 2008 3:38 pm

Dratted tiny laptop keyboard..
As I was about to say before my bout of premature posting.
The photo in question is indeed unlabeled, but you will notice the picture of Paul C. Huth on page 2 of the NYT article linked in the main post is the same person standing at the Stevenson screen in the unlabeled picture.
Also, the current NOAA weather sheet linked on the Mohonk Preserve site with the unlabeled photo lists Paul C. Huth as the observer
Now, does any of that mean the Stevenson screen in the picture is the official one? No. For now we will just have to wait for a documented inspection. It was, however, a fun exploration of the circumstantial evidence.

Chris D.
September 20, 2008 4:59 pm

Apart from the wood chips on the ground, look at the height of the screen from the ground. The observer’s eye level is above the top of the enclosure. I’m thinking the specified height is greater than that(?) And the stand that it’s on appears to be some sort of wooden home-made affair…
Very much looking forward to seeing the survey results!

j. connor
September 20, 2008 7:20 pm

More background information: The spa and pavilion was designed and built by Saratoga Associates
completed in 2005, according to these reviews.
and is connected to the main building by covered walkway.
Also, as a continuation of this little exercise, comparing photos of the grounds from this historic collection taken between 1880 and 1920 to the modern google collection shows the term “relatively unchanged” does not mean “just like it was”.
I swear, I’ve seen a google photo of the place with rows of window ac units hanging out of them… should have saved the link.

j. connor
September 20, 2008 7:23 pm

Blah, just enter Mohonk in the search field of the Library of Congress for the historic photos… Should have predicted that one wouldn’t work as I hoped.

M. Jeff
October 2, 2008 6:43 pm

“An appointment for a site inspection has been set up for the middle of next week.”
Any information concerning the status of the inspection would be appreciated.

October 16, 2008 11:56 pm

Could this be another case of weed blocker under the mulch?

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