Rare 114-Year Record, Kept by Generations, Logs Changing Climate



The rain gauge at Mohonk is the brass 1896 original, supplied by the US Weather Bureau (now called the National Weather Service). (Credit: Linda Keyes/Courtesy Mohonk Preserve)

ScienceDaily (May 7, 2010) — Every day since Jan. 1, 1896, an observer has hiked to a spot at The Mohonk Preserve, a resort and nature area some 90 miles north of New York City, to record daily temperature and other conditions there. It is the rarest of the rare: a weather station that has never missed a day of temperature recording; never been moved; never seen its surroundings change; and never been tended by anyone but a short, continuous line of family and friends, using the same methods, for 114 years.

On top of that, observers have for decades recorded related phenomena such as first appearances of spring peepers, migratory birds and blooming plants. At a time when scientists are wrestling to ensure that temperature readings from thousands of divergent weather stations can be accurately compared with one another to form a large-scale picture, Mohonk offers a powerful confirmation of warming climate, as well as a compelling multigenerational yarn.

The story is told in an article by researchers from Columbia University's Lamont-Doherty Earth Observatory and Mohonk in the current issue of the Journal of Applied Meteorology and Climatology.

Mohonk was founded in 1869 by the Smileys, a close-knit Quaker family that still runs the 7,200-acre property on a high ridge in the Shawangunk Mountains. When the fledgling United States Weather Bureau (later the National Weather Service) founded an official station there, it supplied thermometers, log sheets and other materials; Albert K. Smiley, one of the twin brothers who founded the place, volunteered to man it. The thermometer (occasionally replaced by a new duplicate over the decades) has always been kept in a box out of direct sun, in the same place, a short walk from the Mohonk hotel; a brass rain gauge at the end of a boat dock is the 1896 original. In 1906, Albert's half-brother, Daniel, took over the readings.

In 1930, Daniel's sons Bert and Doc followed. In 1937, Bert's son Daniel Smiley Jr., picked up the job. In addition, Daniel Jr., an old-school amateur naturalist, started recording many other observations, including first spring sightings of various creatures, on some 15,000 index cards. In 1988, the year before Daniel Jr. passed away, he handed his duties to Paul Huth, a longtime friend and employee. Today Huth or one of his staff still walks up to the box at 4 pm every day. The weather log, for many decades kept on hand-written sheets, lacks only 37 days of precipitation data from 1901, 1908 and 1909, due to a missing data sheet, and a few days when observers apparently didn't look at the rain gauge. The temperature record is complete.

Enter another father-son team. In 1971, Edward R. Cook, then serving as a military policeman at nearby West Point, became friends with Daniel Smiley Jr. Later, Cook became a tree-ring scientist and climatologist at Lamont, and began studying conifer trees at Mohonk--some of which turned out to be over 400 years old. From these, he extracted a rough record of weather in the Hudson Valley before Europeans settled. Then Edward Cook's son, Benjamin I. Cook, became a climate modeler at Lamont. It was under Benjamin's leadership that the Cooks and their colleagues at Mohonk began studying the instrumental readings and other data.

Starting in 1990s, Mohonk staffers spent hundreds of hours digitizing the records so they could be analyzed. "It is incredibly rare to have the level of continuity that we have at Mohonk," said Benjamin Cook. "Any one record cannot tell you anything definitively about climate globally or even regionally. But looking closely at sites like this can boost our confidence in the general trends that we see elsewhere, and in other records."

Indeed, the new study finds remarkable correlations with many other widely spread, but less continuous records. At Mohonk, average annual temperatures from 1896-2006 went up 2.63 degrees Fahrenheit. Global measurements in the same time over both land and oceans put the rise at about 1.2 to 1.4 degrees; but land temperatures are rising faster than those over the oceans, and those at Mohonk track the expected land trend closely. As expected also, temperatures are up in all seasons, but increases have been especially evident in summer heat waves, and this has been accelerating in recent years. Prior to 1980, it was rare for the thermometer to surpass about 89 degrees more than 10 days a year; since then, such events have come to Mohonk on at least 10 days a year -- and often, on more than 20 days. At the same time, the number of freezing days has been decreasing--about a day less every five years over the long term, but since the 1970s, at the accelerated rate of a day every two years. This also matches wide-scale observations in North America and elsewhere.

The Mohonk records do not match wider trends in one area. The start of the growing season -- the date on which freezing temperatures end -- has been advancing steadily in many places, but not here. Instead, the total number of yearly above-freezing days is increasing because more unusually warm days are puncturing the winter. As described in an earlier study in the International Journal of Climatology, also by the Cooks and Mohonk staff, the effect has been a sort of an intermittent false spring that may expose some early-flowering plants to frost damage. The earliest flowering native plants like hepatica, bloodroot and red-berried elder are likely to be most affected, said Benjamin Cook. He said it is still too early to tell the ecological effects of such disruptions, but added: "The data from Mohonk will be invaluable for expanding our knowledge of how ecosystems respond to climate change." Temperature data after 2006 has not yet been analyzed, but Mohonk maintains an up-to-date online archive of the weather data accessible to the public.

The new study comes at a time when some skeptics have questioned the accuracy of long-term weather records, on the basis that many stations have been moved or that surroundings have changed, occasionally putting instruments nearer to buildings, parking lots or other possible heat sources that could skew readings upward. However, recent studies including one by scientists at the National Oceanic and Atmospheric Administration have found that such year-to-year inconsistencies cut both ways, and that instruments near developed spots actually more often read too cool rather than too hot. Researchers say every effort has been made to adjust for errors, and that errors one way or the other at individual stations basically cancel each other out, leaving the averages correct.

"Pictures, anecdotes, and cursory glances of poorly sited or maintained sites and weather stations may suggest problems, but until the data is analyzed it is impossible to conclude that the record is compromised by cold or warm biases," said Cook. "The advantage to Mohonk is that we can revisit the record in detail, with minimal corrections. This helps confirm the large-scale trends, and it helps us identify stations with errors that need to be corrected."

As for the long history behind the studies, he said: "We and the Smileys all just happened to be in the right place, at the right time."

Was Nashville flooding spurred by global warming?
May 6th, 2010

From Green Right Now Reports

Seeing the pictures of the flooding in Nashville this past week may have reminded you of other recent U.S. floods — in Fargo, Iowa City and the Mississippi River Valley.

And if you keep up with global warming, you may be wondering if this trend isn’t proving what scientists have been telling us about extreme rain events growing more severe and more frequent under climate change.

That question certainly came up in Nashville, according Rich Hayes, deputy communications director at the Union of Concerned Scientists and a Nashville resident.

“A lot of my friends here have asked me if this disaster is related to global warming. The fact is that climate change increases the probability of some types of weather, including heavy rains and flooding. As average temperatures rise, more rain falls during the heaviest downpours. Unfortunately, that is exactly what we experienced in Nashville over the weekend,” Hayes said in a prepared statement on Thursday.

“Warmer air holds more moisture. We’ve all seen it. Next time you take a shower, notice how the water vapor hangs in the warm air after you turn off the hot water. When warm air holding moisture meets cooler air in the atmosphere, the moisture can condense onto tiny particles to form floating droplets. If those drops get bigger and become heavy enough, they fall as precipitation.

Hayes went on to cite a report by the United States Global Change Research Program, a collaborative effort involving 13 federal agencies, which found that “one of the most pronounced precipitation trends in the United States is the increasing frequency and intensity of heavy downpours.”

As for those climate skeptics who might think the Nashville event is just an extreme example of an otherwise good thing, i.e., more rain. Listen in to the rest of what that report predicts:

“More precipitation is falling during very heavy events, often with longer dry periods in between. Climate models project more heavy downpours and fewer light precipitation events.”

In other words, we get rain that doesn’t really work that well for us anymore. It comes in sudden, heavy downpours that produce a lot of runoff and erosion, and when the water can’t escape, flooding. In between, we get dry spells. Ask any farmer if this is a good thing.

It would be akin to having water to drink one week, but no water the next. Most organisms can’t live that way.

Hayes goes on to note that the rain that fell on Nashville was undoubtedly outside the norm. A record of 13 inches fell on Saturday and Sunday, nearly double the previous record set in 1979, and that followed a hurricane.

All these flood events are different. Fargo and the Mississippi Valley had their own distinct issues. Fargo faced rapid heavy snow melt. In Iowa, the flooding was exacerbated by monoculture farming that has left the flat lands susceptible to run off. But they seem to be happening more frequently.



Increases in Very Heavy Precipitation 1958-2007 (Image: U.S. Global Change Research Program)

In Nashville, the sheer volume of rain in a short time overwhelmed the city. Unfortunately, under climate change models, what’s been outside the norm is becoming the norm.

The report cited by Hayes notes that “very heavy rain and snow events, defined as the heaviest 1 percent of all precipitation events, now drop 67 percent more water on the Northeast; 31 percent more on the Midwest and 20 percent more on the Southeast than they did 50 years ago.” (See image above from the USGCRP.)

“If the fossil fuel emissions that cause global warming continue unabated, scientists expect the amount of rainfall during the heaviest precipitation events across the country to increase more than 40 percent by the end of the century. Even if we dramatically curbed emissions, these downpours would still increase, but by only a little more than 20 percent,” according to the UCS statement.

“It’s going to take Nashville a long time to recover from the flooding,” says Hayes. “But when the flood waters do recede, and local officials turn to the question of how we plan for the future, they need to take climate change into account.”