the climate of amherst, massachusetts

120 Pages·2015·42.26 MB·English

THE CLIMATE OF
AMHERST, MASSACHUSETTS
1836-1985
,
Raymond S. Bradley
Jon K. Eischeid Contribution No. 50
Department of Geology & Geography,
Philip T. Ives
University of Masuchueetts et Amherst
THE CLIMATE
0 F
A M H E R S T , M A S S A C H U S E T T S
Raymond s. Bradley *
*
Jon K. Eischeid
and
+
Philip T. Ives
Contribution No. 50
Dept. of Geology and Geography
·•
University of Massachusetts, Amherst
+
Amherst College
July, 1987

iii
Dedication
We dedicate this publication to the hard work and interest of the
following observers without whom we would know very little about the
climate of Amherst:
Snell Homestead and Amherst College
1835 to 1876 Prof. E. s. Snell
1876 to 1902 Sabra and Mary Snell
1948 to present Dr. P. T. Ives
Massachusetts Agricultural Exeeriment Station (MAES)
1883 to 1889 Dr. c. A. Goessman
1889 to 1895 Prof. c. D. Warner
1895 to 1897 Prof. Leonard Metcalf
1897 to 1928 Prof. J. E. Ostrander
1928 to 1947 Prof. c. I. Gunness
1947 to 1950 Prof. H. N. Stapleton
1950 to 1952 Prof. E. F. Cox
1952 to 1954 Dr. I. J. Pflug
1954 to 1957 Prof. A. B. Barton
1957 to 1960 Dr. R. w. Kleis
National Weather Bureau Cooperative Station
1966 to present Personnel of Amherst Wastewater Treatment Facility
iv
ACKNOWLEDGEMEN'rS
Compilation of this publication would obviously not have been
possible without the dedication of all the observers who kept their
meteorological records, day in and day out, regardless of the weather!
This summary is a tribute to their efforts. In particular, Bradley and
Eischeid wish to acknowledge their co-author, Dr. Phil Ives of Amherst
College and a native of South Amherst who has been the driving force
behind this publication. He has not only carefully kept his own
observations every day for almost 40 years, but has meticulously
screened those earlier records of Professor Snell and of the
Massachusetts Agricultural Experiment Station (MAES), uncovering
numerous errors in compilation and transcription which had occurred over
the years. It was Dr. Ives who recognized the importance of parallel
records kept at Amherst College and MAES in the late 19th century,
enabling a composite 'homogeneous' temperature series to be constructed
(see Appendix B). As a result, the Amherst records are now recognized
as one of the most important meteorological series in the United States.
Thanks are also due to Marie Litterer, who drafted many of the
figures, Alice Bishko who typed and organized this publication and the
staff of the Amherst College and University of Massachusetts Archives.
v
TABLE OF CONTENTS
CHAPTER l Observations on the Climate of Amherst, Massachusetts. l
CHAPTER 2 Average Monthly Data •.•••••••••••••••••••••••••••••••• 15
CHAPTER 3 Daily Temperature and Precipitation Summaries for
Amherst............................................... 33
CHAP'rER 4 Long-Term Changes in the Climate of Amherst........... 49
APPENDIX A Day-by-Day Averages of Temperature (Average Maxima,
Means and Average Minima) and Precipitation (Totals
and Percentage of Days with Precipitation Occurring).. 61
APPENDIX B Details of Weather Stations and Equipment and Cor-
rection Factors Used.................................. 87
APPENDIX C Listing of Data and Tables of Extreme Months, Years
and Seasons........................................... 95
vi
LIS'r OF ·rABLES
Table 1 Probabilities of Average Monthly Temperatures Being
Less Than the Threshold Values Shown (based on data
for 1836-1984)....................................... 17
Table 2 Freeze Probabilities for Amherst Based on Period
1951-1973 (from Climatological summary for Amherst,
Dept. of Commerce, NOAA) •••.•.•••.•.•..•••••••••••••• 42
Table 3a. The Climatological Year (for use in Table 3b) •••••••• 47
·rable 3b. Percent Probability of Receiving Trace (Tr) or Less
and (at least) the Amounts Indicated during 1-week
Periods.............................................. 48
LIS'r OF FIGURES
Figure 1. Location of Amherst within the Commonwealth of
Massachusetts........................................ 2
Figure 2. Cover page from Snell's First Meteorological Journal
(reproduced from Amher~t College Weather Station
Records, Amherst College Archives, by permission of
the Trustees of Amherst College) ••••••••••••••••••••• 5
Figure 3. Two pages selected from Snell's meteorological
journal, recording weather observations in January
1839. Snell keenly observed the aurora borealis (see
remarks for January 6th, 10th, 14th and 19th as well
as other 7 meteorological phenomena such as haloes
around the sun and moon (e.g. January 9th and 15th).
(Reproduced from Amherst College Weather Station
Records, Amherst College Archives, by permission of
the Trustees of Amherst College.).................... 6
Figure 4. Location off weather stations within the Town of
Amherst•••••••••••••••••••••••••••••••••••••••••••••• 9
Figure 5. Average monthly temperatures for 1836-1875 (lower
line) and 1936-1975 (upper line) ••••••••••••••••••••• 16
Figure 6. Heating degree days (65°F base) for 1/2 month
intervals, based on 35 years of data from Amherst
College weather station (1949-1983) •••••••••••••••••• 29
vii
Figure 7. Cumulative plot of half-monthly heating degree day
totals. Annual total is expressed as 100% ••••••••••• 20
Figure 8. Average monthly relative humidity (x) and the
highest and lowest monthly average in the 1929-1958
period.····•••••••••••••••••••••••••••••••••••••••••• 22
Figure 9. Average hourly wind speed, by month, based on record
ings made on the roof of South College (on the
University of Massachusetts). The measurement site
and the recording instruments used are shown in
Plates 3 and 4 (p. 11 and 13). The average of daily
maximum winds is also shown ('x max') as are the
highest (one minute averages) recorded at the station
in each month ('abs. max.').......................... 22
Figure 10. Average monthly barometric pressure, reduced to sea
level (x) recorded at Massachusetts Agricultural
Experiment Station, together with the average
monthly maxima and mimima and the all-time extremes.. 24
Figure 11. Average monthly record of 'bright sunshine'
recorded at the Massachusetts Figure 11. Average
monthly record of 'bright sunshine' recorded at the
Massachusetts Agricultural Experiment Station site.
Measurements were made by means of the glass sphere
shown in Plate 3b. Also shown are the highest and
lowest monthly averages ('abs. max.' and 'abs. min.')
and the maximum possible number of hours at this
latitude............................................. 26
Figure 12. Average monthly bright sunshine as a percentage of
the theoretical maximum amount possible at this
latitude.•••••••••••••••••••••••••••••••••••••••••••• 26
Figure 13. Average percent cloudiness (total clouds of all
types) and the highest and lowest monthly averages
recorded in the period 1889-1958..................... 26
Figure 14. Monthly average precipitation (1836-1984)............ 28
Figure 15. Average monthly snowfall and highest monthly totals
for 2 periods (solid lines = 1889-1958; dashed lines
= 1951-73; both sets of observations from MAES).
Note that snowfall depths are extraordinarily
difficult to measure accurately and differences
between these periods may reflect the observer's
methods as much as any significant change in snow-
fall amounts••••••••••••••••••••••••••••••••••••••••• 28
viii
Figure 16. Snowfall amounts from year to year as recorded by
Dr P. T. Ives at Amherst College since 1948.......... 29
Figure 17. Number of storm events in which total water fall
(rain and melted snow) exceeded 2 inches. Data shown
are based on three sets of observations: Professor
Snell's (top), the Massachusetts Agricultural Experi-
ment Station's (middle), and Dr. Ives' (bottom)...... 29
Figure 18. Largest storms recorded in each month and the years
in which these records were set ••••• •••••••••••••••• 30
Figure 19. Record of barometric pressure, wind velocity (one
minute averages) and temperature during the passage
of the Great Hurricane of September 21, 1938......... 32
Figure 20. Daily temperature statistics averaged over the period
1926-1984. The 5 lines show (from top to bottom):
(a} the highest recorded on each respective day in
this interval ('absolute maximum'), (b) the average
of all the daily maximum temperatures ('mean maxi
mum'), (c) the daily average temperature (average of
[daily maximum and daily minimum]/2), (d) the average
of all the daily minimum temperatures ('mean mini
mum'), (e} the lowest recorded on each respective day
in the interval 1926-1984 ('absolute minimum'). An
enlarged version of this diagram (divided by month)
B...............................
is given in Appendix 36
Figure 21. Average daily precipitation based on the period 1926-
1984. A weighted running average (dark line) has
been plotted to give a sense of longer-term (weekly)
variations. An enlarged version of this diagram
(divided by month) is ven in Appendix B............ 37
Figure 22. Number of times precipitation was recorded on each
day of the year in the 59-year interval 1926-1984
(expressed as a percentage on right-hand axis). A
weighted running average (dark line) has been plotted
to give a sense of long-term (weekly) variations. An
enlar~ed version of this diagram (divided by month)
is given in Appendix B •••• o•••••••••••••••••••••••••• 38
Figure 23. Maximum precipitation recorded on each day of the
year in the interval 1926-1984. A weighted running
average (dark line) has been plotted to give a sense
of long-term (weekly) variations..................... 45
ix
Figure 24. Seasonal variations in temperature since 1836. (a)
Spring (March, April, May); (b) Summer (June, July,
August); (c) Autumn (September, October, November);
(d) Winter (December, January, February); Long-term
(Low frequency) variations are shown by the darker
solid lines (9-year binomial running mean, Gaussian
weigh ts) • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • . • • • • • • • . • • 50
Figure 25. Annual temperatures and precipitation variations
since 1836........................................... 52
Figure 26. Seasonal variations in precipitation since 1836. (a)
Spring (March, April, May); (b) Summer (June, July,
August); (c) Autumn (September, October, November);
(d) Winter (December, January, February)............. 54
Figure 27. Dates of last temperature of 32°F or less recorded
in the Spring (left) and the first temperature of
32°F or less recorded in the Fall (right). Data
since 1961 (dashed line) from Amherst College; prior
to that from MAES.................................... 57
Figure 28. Yearly variations in the length of the 'frost-free'
season, as defined by the number of days between the
dates of the first and last recordings of 32°F or
less. Average for the period is 152 days............ 58
Figure 29. Yearly variations in 'growing season' (May-September)
average temperature (a) and precipitation (b) since
1836. • • . . • • . • • • • • • • . • • • • • • • • . • • • • • • • • • • • • • . • • • . • • • • • • 59
Plate
Plate l Ebenezer s. Snell, Professor of Mathematics and Natural
Philosophy, Amherst College, who started regular weather
observations in Amherst in 1835. (reproduced from Snell
Family Papers, College Archives, by permission of the
Trustees of Amherst College)............................ 4
Plate 2 (Above) Snell homestead where earliest meteorological
observations were made.
(Below) Plaque on wall of Snell homestead............... 8