Friday, February 26, 2016

Blue Hill Observatory Field Trip

Posted by Richard Primack

“A regular snowstorm has commenced, fine flakes falling steadily, and rapidly whitening all the landscape. In half an hour the russet earth is painted white even to the horizon. Do we know of any other so silent and sudden a change?” 
Henry David Thoreau, November 28, 1858

On February 6, the Boston University Biogeosciences Program had a field trip to the Blue Hill Observatory, the longest running weather station in the United States. The Observatory was established in 1884 on a hill 10 miles south of Boston. We often use data from the Observatory in our research to determine if long-term phenological patterns are affected by temperature and rainfall. The Blue Hill Observatory is uniquely useful for our purposes because its scientists have incorporated earlier weather observations into their records, extending temperature data back to the 1830s and overlapping Henry David Thoreau’s phenology observations from Concord. For us, the key finding of the Observatory is that the temperature of Boston has been getting warmer over the past 133 years.

The Blue Hill Observatory with weather instruments on top:

At the base of the Observatory, BU post-doc Eli Melaas explains the function and history of various instruments. To his right is a designated spot that is regularly cleaned off to record the amount of snowfall and the rate of snowfall:

This rain gauge has a perimeter of flaps to create wind turbulence and create a more standardized measure of precipitation. The Blue Hill Observatory is a pioneer in developing and improving weather instruments:

On the roof of the Observatory, sunlight intensity is recorded when sunlight focused by the glass ball burns holes in a standard paper sheet as the sun traverses overhead during the course of the day:

A special feature of the Observatory is that it uses both the original equipment and more modern equipment in order to provide continuity in its measurements. Here are the original barometers that are still used to record air pressure:

Wind speed from the anemometers on the roof is recorded on a moving sheet of paper inside the Observatory:

Friday, February 12, 2016

New article in American Scientist

Posted by Amanda Gallinat

Dr. Richard Primack and I recently authored an article entitled "Spring Budburst in a Changing Climate" in the journal American Scientist; the article hits shelves next month! 

In the article, we describe the wide range of work the Primack Lab has done to investigate how climate change impacts the timing of leaf-out and other spring events in the temperate forests of historic Concord, MA and beyond. We summarize the key results found by past and present members of the Primack Lab through combining historic data sets, like the field notes of Henry David Thoreau, with current observations of spring phenology, as well as novel experiments. 

One of the key findings we describe is that in Concord, climate change has resulted in varied shifts in timing between leaf-out, flowering, bird arrivals, and insect emergence. Since Thoreau recorded his observations in the 1850's, we estimate the following shifts have occurred in the timing of spring events as a result of climate change:

These estimates of long-term changes in spring timing demonstrate how the effects of climate change could be problematic for birds that are not responding to warming temperatures as quickly as their insect prey. In fact, the strong effect of warming on leaf-out and flowering in Concord, MA, combined with the limited ability of migratory birds to track temperature changes on their MA breeding grounds, has altered the overall order of events from Thoreau's time to present:

In addition to these taxon-level shifts, we delve into how species vary in their leaf-out times and responses to climate change, the benefits of leafing out early (i.e. a longer growing season in which to photosynthesize) and the dangers of leafing out early (i.e. an increased risk of vulnerable young leaves encountering frost). We also identify some important next steps in the study of climate change and phenology, including a greater focus on autumn events like leaf senescence and fruit ripening.

To read the American Scientist article, click HERE or e-mail for a PDF. 

Sunday, February 7, 2016

Warm Christmas brings flowers to Concord

Posted by Richard B. Primack

“Snow driving almost horizontally from the northeast and fast whitening the ground.”  
-Thoreau’s Journals, December 25, 1855

In contrast to the white, snowy Christmas day that Thoreau experienced and that we typically expect in New England, record-breaking warm temperatures in autumn and December triggered a surprising flash of flowering throughout Concord and metropolitan Boston this winter. 

Common groundsel flowering on the edge of Walden Pond on Christmas

On Christmas day of 2015, a visitor to Concord could note the open pink flowers of Japanese quince in the center of Concord and the white flowers of hellebores in gardens. The Blue Hill Observatory reported that the temperature on Christmas day reached 64 degrees, beating the old record of 62 degrees and around 30 degrees warmer than normal for this time of year!

Brussel sprouts still green in the Hugh Cargill Community Garden in Concord on Christmas

This autumn in Boston is tied for the second warmest on record. As a result, some garden plants from the past year, such as Brussel sprouts and lettuce, were never killed by hard frosts, and were still growing and looking ready to eat on Christmas day. Around the edge of Walden Pond, red clover and common groundsel also continued to produce flowers throughout the autumn and into winter.

Yellow wood sorrel plant still growing actively because of the lack of killing frost

After our astonishingly warm week of Christmas, our classic New England winter finally arrived. A snowstorm on December 29th deposited an inch of heavy slush on the landscape, and a cold night then froze the slush to the ground. So long, warm Christmas; so long, flowers—we’ll see you again in the spring!

Read my full article about the uncommon winter in the Concord Journal: HERE