United States

Department of

Agriculture

Forest Service

Northeastern

Research Station

General Technical

Report NE-305

Amey Schenck Bailey

James W. Hornbeck

John L. Campbell

Christopher Eagar

Hydrometeorological Database

for Hubbard Brook Experimental

Forest: 1955 – 2000
Published by: For additional copies:

USDA FOREST SERVICE USDA Forest Service

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Abstract

The 3,160-ha Hubbard Brook Experimental Forest (HBEF) in New Hampshire has

been a prime area of research on forest and stream ecosystems since its

establishment by the USDA Forest Service in 1955. Streamflow and precipitation

have been measured continuously on the HBEF, and there are long-term datasets

for air and soil temperature, snow cover, soil frost, solar radiation, windspeed and

direction, and humidity. This information has provided the basis for hundreds of

publications by Forest Service and cooperating scientists on numerous aspects of

forest hydrology research as part of the ongoing Hubbard Brook Ecosystem Study.

This report updates the tables, methods, watershed descriptions, and other

pertinent data in “Thirty Years of Hydrometeorological Data at the Hubbard Brook

Experimental Forest, New Hampshire” (General Technical Report NE-141).

The Authors

AMEY SCHENCK BAILEY, JAMES W. HORNBECK, JOHN L. CAMPBELL, and

CHRISTOPHER EAGAR are, respectively, forest technician, research forester,

research ecologist, and research ecologist with the Northeastern Research Station’s

Louis C. Wyman Forestry Science Laboratory at Durham, New Hampshire.

Manuscript received for publication 24 October 2002
1

Foreword

C. Wayne Martin, retired research forester with the Northeastern Research Station, was

site manager at the Hubbard Brook Experimental Forest from 1969 to 1999. One of

his many responsibilities was overseeing the collection of data summarized in this

report. Wayne supervised many people and participated in all aspects of data collection,

including calibrating and maintaining instruments, processing and checking data, and

ensuring high standards of quality control. That many individuals and groups use

Hubbard Brook data with great confidence is a reflection of Wayne’s personal

commitment to excellence. Accordingly, this report is dedicated to C. Wayne Martin in

recognition of his invaluable efforts in facilitating the important research conducted at

Hubbard Brook.
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Introduction

Scientists with the USDA Forest Service and cooperating

researchers have been conducting studies on forest

hydrology at the 3,160-ha Hubbard Brook Experimental

Forest (HBEF) since its establishment in 1955 within

the White Mountain National Forest near Thornton,

New Hampshire. Since that time, streamflow and

precipitation have been measured continuously on the

HBEF, and data on air and soil temperature, snow cover,

soil frost, solar radiation, windspeed and direction, and

humidity have been collected on one or more of the

HBEF’s nine watersheds as part of the ongoing Hubbard

Brook Ecosystem Study (HBES). These data serve as the

foundation for world famous research on the cycling of

water, nutrients, and energy in forests and related aquatic

ecosystems, and are fundamental to research conducted

by HBES scientists. In this report we describe and

summarize the many long-term data sets maintained by

Forest Service personnel at Hubbard Brook. Included are

starting dates, equipment locations, methods, watershed

descriptions and data summaries. This report updates

the tables, trends and methods in “Thirty Years of

Hydrometeorological Data at the Hubbard Brook

Experimental Forest, New Hampshire” (Federer 1990).

Topography and Vegetation

The center of HBEF is at latitude 43o56’N and

longitude 71o

45’W in the southwestern corner of the

White Mountain National Forest. Elevation ranges from

252 m near HBEF Headquarters (HQ) at the east end to

1,015 m at the summit of Mt. Kineo at the west end

(Fig. 1). The HBEF is a bowl-shaped watershed basin

with many subwatersheds that drain into Hubbard

Brook, which flows easterly into the Pemigewasset River,

a major tributary of the Merrimack River.

Approximately 14,000 years ago, HBEF was covered by

continental glacial ice. The ice sheet removed the

preglacial soil and smoothed the surface of the schist and

granite bedrock. The bedrock surface has weathered little

since glaciation. When the ice melted, debris in the

glacier became the stony till in which today’s soil has

formed. The till thickness over bedrock ranges from zero

to several meters. Four thousand years after glaciation,

forests covered the landscape, which along with the

humid, cool, continental climate, caused the

development of a typical spodosol soil profile: a black

organic forest floor over a highly leached, thin gray

horizon, and then a red-orange horizon of accumulated

Figure 1.—Locations of watersheds and stations on the Hubbard Brook Experimental Forest.
3

iron and a yellowish-gray subsoil ranging from coarse

and sandy to a dense hardpan.

From 1890 to 1920, the original mixed coniferhardwood forest at HBEF was cut heavily for sawtimber

and fuelwood. The resulting forest release and

regeneration led to the current northern hardwood

forest, which is dominated by sugar maple (Acer

saccharum Marsh.), American beech (Fagus grandifolia

Ehrh.), and yellow birch (Betula alleghaniensis Britt).

Balsam fir (Abies balsamea (L.) Mill.) and red spruce

(Picea rubens Sarg.) are found primarily at higher

elevations, particularly on north-facing slopes. Although

trees in the 80- to 100-year class dominate, the cutting

left many residual trees that today are more than 200

years old. Apart from salvage logging following the

hurricane of 1938, the forest has been undisturbed since

1920 except for recent research treatments.

Hydrometeorologic Network

Early construction of streamgages on small

subwatersheds within HBEF occurred side by side on

the south-facing slope, where watersheds are well

defined, accessible, and of suitable size for weir

construction and study. Weir construction on southfacing tributaries to Hubbard Brook (Watersheds 1 - 6)

began in 1955 and continued through 1963. Gaging on

the north-facing slopes was established on Watershed 7

in 1965, Watershed 8 in 1969, and Watershed 9 in 1995

(Fig. 1, Table 1). A watershed is the area upslope from

the streamgage, defined by its ridgelines, that contributes

water to the stream channel at the gage location. The

gaged watersheds were numbered in the order constructed.

Openings were cut in the forest to about 2 tree heights

or more in diameter in or near each gaged watershed.

These openings have at least a standard precipitation

gage and are numbered from 1 to 25 (Fig. 2). Station 18

was a temporary station in Watershed 2; its data are not

reported here. All other stations are currently in

operation. Stations 1, 6, 10, 14, 19, 22, and 23 have a

weight-recording precipitation gage; Stations 1, 6, 14,

17, 23, 24, and HQ have a temperature and humidity

recorder (hygrothermograph). A variety of sensors has

been maintained at the HQ weather station (Station 22)

over the years and it is the original site for electronically

measured weather data at HBEF.

Four experimental watersheds on the south-facing slope

have undergone treatment since the HBEF was

established. Watershed 2 was clearfelled in 1965 by

cutting all stems and leaving them in place. It was

further devegetated by application of herbicide in 1966,

1967, and 1968. Watershed 4 was commercially cut in

sequential parallel strips (25 m wide) in 1970, 1972, and

1974, resulting in complete cutting and log removal over

the entire area except for a streamside buffer. Watershed

5 was whole-tree clearcut in late 1983. In the fall of

1999, Watershed 1 was manipulated chemically. Fifty

tons of wollastonite (CaSiO3) were applied to evaluate

the role of calcium in regulating the structure and

function of the forested watershed. All of the treated

watersheds have been left undisturbed following

manipulation.

Nearly all of the equipment at HBEF continues to be

operated by mechanical transducers linked to pens on

spring-wound strip-chart recorders. These instruments

Table 1.—Description of watershed features with mean streamflow and precipitation for each

watershed calculated from starting year to 2000

Watershed Streamgage Avg. annual Avg. annual

no. start year Area Slope Aspect streamflow precipitation

ha degrees mm

1 1956 11.8 12.3 Southfacing 828 1322

2 1957 15.6 17.5 Southfacing 916 1315

3 1958 42.4 15.9 Southfacing 831 1324

4 1961 36.1 15.1 Southfacing 875 1358

5 1962 21.9 14.3 Southfacing 881 1389

6 1963 13.2 14.0 Southfacing 917 1423

7 1965 76.4 14.2 Northfacing 949 1450

8 1969 59.4 15.4 Northfacing 925 1471

9 1995 76.1 13.3 Northfacing 994 1493
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represented the state of the art in 1955 and remain

highly reliable in adverse weather conditions. The

instruments are monitored weekly and malfunctions are

repaired immediately. Data from the charts are entered

into computer programs and spreadsheets where they are

analyzed and archived. The data presented here are

available at the Hubbard Brook website

(www.hubbardbrook.org) and updated annually.

Precipitation

Three types of raingages have been used to measure

precipitation at Hubbard Brook: standard, weight

recording, and tipping bucket. All gages are located in

clearings that are maintained to uniform standards such

that any tree beyond a 40-degree angle measured from

the base of the raingage stand is cut down. Each gage has

a shield to reduce wind effects. Raingages are mounted

so that the tops are 2.5 m off the ground; this ensures

that they are above the deepest snowpack.

Precipitation is measured weekly at standard gages

located at 24 stations in or near gaged watersheds and at

HQ (Fig. 2). Weight-recording gages are located at 7 of

the 24 stations for a continuous chart record of how

much rain fell each day. An automated tipping bucket

was installed at the HQ meteorological station in 1981;

a second one was installed at rain gage 23 in 2000.

Tipping buckets provide hourly data, which are

commonly sought after by forest modelers.

Figure 2.—Average annual precipitation (mm) for 1969-2000 (1997-2000 for raingages 23-25)

for each standard gage (circled numbers indicate standard gages; precipitation is in boldface).

Hubbard Brook Valley
5

The daily precipitation for a standard gage is obtained

by prorating its weekly total using daily totals from the

nearest recording gage. Precipitation for an entire

watershed is estimated using the Thiessen weighting

method (Linsley et al. 1958). The daily watershed

precipitation reported is a weighted average of daily

precipitation for several standard gages. The weighting

factor for each gage is the fraction of the watershed area

nearest that gage.

Standard Raingages

Raingage 1 often is used to report average annual rainfall

from a single gage at Hubbard Brook. Using the record

from 1969 to 2000, that value is 1,364 mm. However,

mean annual rainfall at HBEF is characterized by high

spatial variability ranging from 1,220 mm at raingage 22

to 1,522 mm at gage 24 (Fig. 2). These precipitation

trends are related to topography and tend to increase

from east to west, from south to north-facing slopes, and

with elevation.

Total precipitation by gage is strongly controlled by

longitude (Fig. 3). Raingage 10, at Watershed 6, the

westernmost gaged watershed on the south-facing slope,

has the highest average annual rainfall (1,464 mm). Gage

10 receives an average of 100 mm more precipitation

annually than its easternmost counterparts, e.g.,

raingages 1 and 4, which receive average annual rainfall

of 1,364 mm. The east/west trend is not as significant on

the north-facing slope.

Elevation is important when describing precipitation

trends at HBEF (Fig. 4). On both the south- and northfacing slopes there is a 300-m difference between the

lowest and highest raingage. The highest gage receives 70

mm more precipitation annually than the lowest on the

south-facing slope and 40 mm more than the lowest on

the north-facing slope. Gages 3 and 6 receive about 100

mm less annual precipitation than expected for their

elevation on the south-facing slope. Raingage 3 is near

the top of Watershed 1 and has annual average rainfall of

1,319 mm. Gage 6 near the top of Watershed 4, has

annual average rainfall of 1,385 mm. Each is less than 20

m in elevation below the ridgeline. The other highelevation raingage on that ridge, gage 9, is 40 m below

the ridge and does not have unusually low precipitation

(1,432 mm annual average). Because winds at HBEF

often are from the northwest, the south-facing slope is a

lee slope. It may be that raingages 3 and 6 often are in

the region of flow separation at the lee side of a ridgetop

and thus are subject to abnormal wind conditions.

Experimental watersheds at HBEF are arranged on

south- and north-facing slopes. Raingages on the northfacing slope receive up to 150 mm more precipitation

Figure 3.—Average annual precipitation from east to west

(raingages 1-22 estimated from 1969-2000, gages 23-25

from 1997-2000). Solid dots are on the south-facing slopes,

open circles are northfacing. The easternmost site,

Headquarters was assigned a value of zero; all other gages

are the distance (km) from headquarters determined by

longitudinal UTM coordinates.

Figure 4.—Average annual precipitation by elevation for

each standard gage (raingages 1-22 estimated from 1969-

2000, gages 23-25 from 1997-2000). Solid dots are on the

south-facing slopes, open circles are northfacing. Stations 3

and 6 receive less precipitation due to their topographic

positions near the top of the watersheds.
6

annually than gages on south-facing slopes. Much of that

is in the form of snow. Raingage aspect within a

watershed on both south- and north-facing slopes does

not indicate a significant trend in rainfall.

Topography affects precipitation trends at HBEF,

though seasonal variation and the composition of

individual events, e.g. the direction they come from, can

be important. At gage 1, the driest year on record is

1961 with 914 mm of rainfall; the wettest is 1973 with

1,778 mm. These totals indicate year-to-year variability

(Fig. 5).

Watershed Precipitation

Annual watershed precipitation varies by year and

watershed. Watershed 3, the easternmost watershed

serves as the hydrologic control while Watershed 6 is the

biogeochemical control. Precipitation increases from east

to west across south-facing watersheds, reflecting the

pattern recorded with individual raingages. Average

annual precipitation is 1,325 mm at Watershed 3 and

1,423 mm at Watershed 6. These differences are not as

apparent on the north-facing slope, possibly because

north-facing gages are at higher elevations than southfacing gages. The resulting increase in rainfall might be

masking the east/west effect.

Summaries of monthly precipitation are sought for many

uses. At Watershed 3, the average monthly rainfall is 110

mm and has been as low as 24 mm in 1965 (May) and as

high as 354 mm in 1973 (June). However, on average,

watershed precipitation varies little from month to

month (Fig. 6). Tables 2- 4 show monthly precipitation

for Watersheds 3, 6, and 7. (Tables 2 through 20 are in

the Appendix.)

Year-to-year variation is much larger than watershed-towatershed variation (Table 5). The standard deviation of

annual precipitation at all watersheds is about 185 mm

(Table 5). The wettest year from 1956 to 2000 was 1973

as 1,793 mm of precipitation fell on Watershed 3. The

driest year was 1961 with 979 mm recorded on the same

watershed. This dry year included a series of dry months

(Table 2). The record precipitation in 1973 is attributed

to abnormally high rainfall in June and December. The

354 mm of precipitation in June 1973 is the highest

monthly total on record.

Differences in monthly precipitation among watersheds

are smallest in the summer months and largest in

November through April, suggesting that snowfall varies

spatially more than rainfall does. Using the criterion of

>1 mm for a “rain day,” slightly better than 1 day in 3

experiences precipitation in the winter months and rain

falls less than 1 day in 3 during the summer months.

The largest storms at HBEF produce total rainfall of 100

to 200 mm over several days (Table 6). These storms can

occur any time of year, usually causing local or regional

flooding. The HBEF record began shortly after the

severe New England hurricanes of 1954 and 1955. Only

1 of the largest 20 storms on record (October 5-10,

1962) was a tropical hurricane. The storm periods in

Figure 5.—Total annual precipitation

at raingage 1 (1956-2001).
7

Table 6 include consecutive days with precipitation.

Most of the precipitation fell in a shorter period than

shown. The high precipitation events in winter occurred

with temperatures at or above freezing, and were

predominantly rain events.

Streamflow

Streamgages are located at the bottom of the 9 gaged

watersheds at HBEF and have been running

continuously from as early as 1955 (Fig. 1, Table 1).

Small watersheds were surveyed and chosen for gaging

by their accessibility, size, and proximity to other gaged

watersheds. Construction of the streamgages at HBEF is

described in Reinhart and Pierce (1964). To prevent

leakage, each gage is anchored to bedrock. The

streamflow is forced over a V-shaped dam, also called a

V-notch weir. The height of water behind the dam

increases as streamflow increases. This height is measured

continuously by a float attached mechanically to a pen

on a spring-wound strip-chart recorder. For each day, 2

to 130 points on the chart trace are digitized depending

on the rate of change of flow. These “gage heights” are

converted to streamflow rate by calibration factors and

then integrated to give daily streamflow. The streamgages

on Watersheds 5-8 have a rectangular (modified San

Dimas) flume in series with the V-notch weir. When

streamflow surpasses the height of the V-notch, the

depth of the water in the flume is recorded as the

measure of streamflow. Both V-notches and flumes are

heated by propane burners to keep them free of ice. This

allows continuous measurement of streamflow

throughout the year.

Streamflow rate is measured as volume per unit time

(L/s) and is proportional to the watershed area. To make

streamflow comparable among watersheds of different

areas, the streamflow rate is divided by watershed area to

give units of depth per unit time (over the entire

watershed area). After integrating over a given time,

streamflow is expressed in millimeters, and is directly

comparable to precipitation.

Streamflow varies considerably from day to day and

season to season in response to precipitation, soil drying

by evapotranspiration, and snow accumulation and melt.

Hydrographs for a dry, normal, and wet year for

Watershed 3 (the hydrologic control) are shown in

Figure 7. The graphs illustrate how annual hydrologic

activity varies by day and by season.

Streamflow also varies considerably from year to year in

response to variation in annual precipitation. The

highest annual streamflow on Watershed 3 (1,414 mm)

occurred in 1996 and the lowest (436 mm) in 1961

(Table 7). These values correspond respectively to years

of the second highest and lowest annual precipitation.

Average annual streamflow at Watershed 3 is 831 mm.

The standard deviation of annual streamflow is about

200 mm for all watersheds (Table 8), and is similar to

that for precipitation (185 mm).

Figure 6.—Average monthly

precipitation (solid bars) and

streamflow (open bars) for

Watershed 3 (1958-2000); data

used to calculate averages are

from Tables 2 and 7.
8

Figure 7.—Daily streamflow at Watershed3 for a) dry, b) average, and c) wet years; data used

in calculations from from Table 7.
9

Monthly streamflow is highly seasonal (Fig. 6).

April has the highest streamflow because the

snowpack that has accumulated through the winter

typically melts during this month. Streamflow is

lowest in August when summer evapotranspiration

rates are highest. Tables 7, 9 and 10 show monthly

streamflow for Watersheds 3, 6, and 7.

During the snow-free period, streamflow generally

increases from east to west across the gaged

watersheds due to the precipitation pattern.

Average annual streamflow from 1969 to 2000 was

882 mm for Watershed 3 (the easternmost

watershed) and 975 mm for Watershed 7 (the

westernmost). Snow melts later on north-facing

watersheds (7, 8, and 9) than on the south-facing

watersheds (1 to 6) due to the higher elevation and

northern aspect. Consequently, March streamflow

is lower and May streamflow is higher on

Watersheds 7, 8, and 9. In April, peak flow occurs

later in the month on these watersheds, though the

average April total is similar at each site.

The highest monthly streamflow recorded for Watershed

3 is 435 mm in April 1969 (Table 7) vs. 409 mm for

Watershed 7 in May 1971 (Table 10). Both of these

months had normal precipitation (Tables 2 and 4),

indicating that the high streamflows were caused solely

by snowmelt runoff.

Monthly streamflows of only 1 or 2 mm are common

during summer months (Tables 7, 9-10). In winter,

streamflow is maintained for long periods at about 50

mm/day due to continuous melt from the bottom of the

snowpack. At Watershed 3, the minimum flow in

January and February is about 9 mm (Table 7). The

lowest winter streamflow on record occurred in February

1980 due to a lack of snow. During that year, a deep soil

frost delayed snowmelt runoff.

The 20 highest peak flows at HBEF (Table 11) are not

well correlated with the 20 largest precipitation events.

Melting snow along with rain occurred during 6 of the 8

highest streamflow peaks. Heavy rain in summer rarely

causes high streamflow because the soil is somewhat dry

from evapotranspiration. Only 2 of the top 20

streamflows occurred in the summer. From June 27 to

July 1, 1973, the greatest rainfall recorded (212 mm)

produced only the 13th highest streamflow event.

Flood return periods and frequency of streamflow are

two measurements of particular interest to hydrologists

and engineers. Calculating the flood return period

requires knowledge of the highest streamflow rate

recorded each year (see Table 12 for Watershed 3).

Frequency of streamflow occurrence is shown by flowduration curves (Fig. 8). Daily flow greater than 10 mm

occurs about 5 percent of the time but contributes 37

percent of the annual total. Daily flow of less than 1 mm

occurs on more than half the days but contributes only

10 percent of the annual total.

Flow recession after storm peaks is rapid at HBEF,

particularly from June through September when the trees

have fully developed leaves and evapotranspiration is high.

Streamflow Response to Treatments

The “paired watershed” method at HBEF is

fundamental to research, i.e., one watershed is treated

while another remains an untreated reference. Before

treatment, the water budgets of the paired watersheds

ideally would be identical so that any differences after

treatment could be interpreted as treatment effects.

Because no two watersheds are identical, regression

comparisons of the two watersheds before treatment are

used for calibration. At HBEF, experimental treatments

entailing timber removal were carried out on three

south-facing gaged watersheds (Hornbeck, et al. 1997).

Responses in annual water yield varied among treatments

but increased initially and then decreased as the forest

regenerated (Fig. 9). Most of the increases in water yield

occurred during the growing season and some peak flows

increased. Snowmelt volume did not change but the

snow melted earlier on treated watersheds.

Figure 8.—Flow-duration curve shows average number of

days in a year from 1958-2000 that streamflow is greater

than previous amount for Watershed 3.
10

Figure 9.—Estimated change in water yield for watersheds 2, 4, and 5 after treatment. Change

was calculated by subtracting treated streamflow yield from estimates of what yield would have

been if watershed had not been treated.

Water Budget

The annual water balance at HBEF for Watershed 3 is:

Precipitation (1,326 mm) = Streamflow (833 mm) +

Evapotranspiration (493 mm)

Thus, 63 percent of the precipitation that enters

Watershed 3 leaves as streamflow while 37 percent is

returned to the atmosphere by evapotranspiration.

The water budget is based on long-term measurements

of precipitation and streamflow. Assuming that bedrock

at HBEF is water tight, precipitation enters a watershed

and, after short periods of storage in the soil or

snowpack, leaves as streamflow or evapotranspiration

(water evaporated directly from the leaves, soil, or snow).

Seepage through fractures in the bedrock, by leaks under

the streamgage, or laterally through the soil into adjacent

watersheds may occur but are thought to be negligible,
11

an important assumption in much of the research at

HBEF. The streamgages are anchored to bedrock and

maintained carefully to eliminate leaks. The watershed

area surveyed using the topographic divide between the

watersheds is assumed to be the same as the bedrock

divide. Geologic surveys, behavior of bedrock wells near

HQ, and annual precipitation minus streamflow suggest

only a small amount of water is gained or lost by

seepage. Soil water is fully recharged around May 31 of

each year after snowmelt; little change in storage is

thought to occur from one year to the next.

The period from June 1 to May 31 is a “water year.”

Analysis of hydrologic data by water year is useful when

the effect of change in water storage should be

minimized. Annual geochemical inputs and outputs that

have been published for HBEF use the June 1 water year.

Annual precipitation, streamflow, and

evapotranspiration for Watershed 3 using a June 1 water

year are shown in Table 13.

Variation in precipitation minus streamflow among

water years is small compared to variation in

precipitation or streamflow (Fig. 10). At HBEF, this

estimate of evapotranspiration usually ranges from 450

to 600 mm. Differences in evapotranspiration among

years occur because evaporation of intercepted water in

Figure 10.—Total annual precipitation, streamflow, and evapotranspiration

at Watershed 3 for the water year beginning June 1 (1958-2000).

Evapotranspiration is precipitation minus streamflow (Table 13). The mean

on each graph is calculated with 43 years of data.
12

Figure 11.—Maximum water content of snowpack at snow course Stations 2 and 17.

the canopy is greater with higher precipitation, and

because dry summers result in lower transpiration.

Following harvest treatments, evapotranspiration

decreases for several years because the cover of

regenerating vegetation is incomplete (see values marked

with T in Table 14). However, only several years of

regrowth are sufficient to restore the preharvest rate of

evapotranspiration.

Snow and Frost

At HBEF, snow depth and water content has been

measured continuously under the forest canopy near

selected raingage stations. Each “snow course” consists of

an area of approximately 0.25 ha and is designated by

the nearby gage number. On each weekly measurement

date, 10 points are sampled for depth and water content

at intervals of 2 m along a line. On the next date, a

parallel line, 2 m from the previous line, is used. Values

for snow depth and water content from the 10 points are

averaged. The number of snow courses used in any year

has varied, first as new locations were added, then as the

network was reduced to eliminate sites with similar

values. On the south-facing side, only Station 2 has a

continuous record, and on the north-facing side, only

Station 17. Snow-water contents measured at these two

locations are shown in Figure 11. Maximum snow water
13

content varies from year to year but averages about 200

mm at snow course 2 and 300 mm at snow course 17.

Station 2 has an elevation of 560 m and reflects low- to

mid-elevation hardwood forests on south-facing slopes at

HBEF. Station 17 has an elevation of 893 m and reflects

a mixed hardwood-conifer forest at high elevation on the

north-facing slope. The earliest HBEF publications

summarize snow-course data and address snow

conditions at HBEF (Sartz and Trimble 1956).

Snow generally accumulates more and lasts weeks longer

at Station 17 than at Station 2 (Fig. 12) due to its aspect

and topographic position. This causes the delay in

snowmelt streamflow on the north-facing watersheds.

The five lowest snow years on the south-facing side and

the corresponding maximum water content of the

snowpack were 1983 (61 mm), 1981 (66 mm), 1991 (89

mm), 1985 (99 mm), and 1995 (112 mm). The five

deepest snow years on the south-facing side and

corresponding highest water contents were 1962 (254

mm), 1982 (335 mm), 1963 (340 mm), 1971 (361

mm), and 1969 (366 mm). At Station 17, peak water

contents usually are 100 to 200 mm higher than at

Station 2 (Fig. 11).

The density of “ripe” or melting snow at HBEF is about

0.35, so maximum depths are at least 3 times the

maximum water content. Thus, depths reach 0.3 to 1 m

on the south-facing side and approach 1.5 m at high

elevation on the north-facing side.

Soil frost is measured at each snow course. The ground is

probed with a ski pole to detect the presence or absence

of frost at 2 points adjacent to each of the 10 snow

sample points. At the first 2 points for which frost is

detected, the soil is excavated and frost thickness is

measured.

For many years during the late 1950’s and early 1960’s,

frost was seldom detected (Table 15). It was not

measured in the late 1960’s. Since 1970, frost has been

present in February at south-facing Station 2 about 1

year in 3 (Table 15). At Station 17, frost was detected at

some points every February until the late 1990’s. In

heavy frost years, all points can have frost, with thickness

exceeding 10 cm. The greatest frost depth usually occurs

during winters of thin and late snow cover.

Frost develops in December in the absence of snow cover

and can thicken if snow is thin in January. Once an

insulating snow blanket is present, frost begins to melt

from below because the soil is warmer at greater depths.

A light, early frost may disappear in January or February

as the snowpack thickens. Heavy frost persists until

spring when melting occurs from above.

In 1994, a snow course was established near HQ at an

elevation of 252 m. Early soil frost has been present there

every year to date due to cold air inversions that occur at

lower elevations. These inversions result in air temperatures

that are well below freezing in the late fall and early winter

before the onset of an insulating snowpack.

Figure 12.—Average snow-water

content (1965-2000) by month for

snow course Stations 2 and 17.
14

Air Temperature

Air temperature has been measured by

hygrothermographs at seven locations at HBEF. The

temperature sensor is a liquid-filled Bourdon tube that

bends as the air temperature changes, mechanically

driving a pen across a clock-driven chart. The maximum

and minimum temperatures for each day (midnight to

midnight) are read from the charts. The mean

temperature for the day is calculated by averaging the

maximum and minimum values. The

hygrothermographs are housed in standard shelters

(Stevenson screens) near the middle of openings at

weather stations HQ, 1, 6, 14, 17, 23, and 24.

Maximum daily temperature at Station 1 averages –

3.8o

C in January and 23.8oC in July (Table 16).

Minimum daily temperature averages –12.9o

C in

January and 13.5o

C in July (Table 17). Mean daily

temperature averages -8.3o

C in January and 18.7oC in

July (Table 18). The average annual temperature at

Station 1 was 5.6o

C from 1956 to 2000, 6.4oC at HQ

from 1957 to 2000, and 4.1o

C at Station 14 from 1958

to 2000. The record high temperature at HBEF, 37o

C,

was recorded at HQ on June 18, 1994. The record low,

–37o

C, occurred at Station 14 on January 15, 1965.

Daily variation of air temperature is considerable at

HBEF. The range in maximum, minimum, and mean

daily temperatures is approximately 35o

C in winter and

15 to 20o

C in summer. Variation among years in average

monthly, maximum, minimum, or mean temperature is

greater in the winter than in summer and exceeds 10o

C

(Tables 16-18). Monthly minimum temperatures vary

more from year to year than monthly maximums (Tables

16, 17).

Long-term average monthly temperatures generally

decrease with increasing elevation, from HQ at 252 m,

to Station 17 at 905 m (Table 19). Only for minimum

temperatures in summer does cooling with elevation fail

to hold. Nighttime cooling causes the heavier, colder air

to move downslope. This creates a valley temperature

inversion that includes HQ. From May through

September, the minimum temperature average at HQ is

lower than at Station 1.

The growing season is defined as the period between the

last frost in spring and the first frost in autumn. If we

use a minimum temperature of 0o

C at Station 1, the

growing season on average begins May 11 and ends

October 3 (146 days long). If –1o

C is used as the

criterion, the growing season increases by several days.

Compared to Station 1, the average growing season is 9

days shorter at HQ and 7 days shorter at Stations 6 and

14. The shorter growing season at HQ compared to

Station 1 is caused by the valley temperature inversion.

An increasing trend in air temperature at Station 1 from

year to year is not apparent for the period 1956 to 2000

(Fig. 13). Annual mean air temperature for January,

April, and July varies considerably from year to year but

the averages do not show a trend upward or downward.

Solar Radiation

Solar radiation has been measured at HQ since 1958.

Before 1981, several bimetal recording pyranographs

Figure 13.—Annual mean temperatures

for Station 1 (1956-2000) for July, April,

and January.
15

(actinometers) were used. Since that time, a Li-Cor solar

cell sensor has provided hourly data on solar radiation. A

pyranograph operates as a backup and provides

comparable data.

Solar radiation averages about 5 megajoules per square

meter (MJ/m2

) in the early winter months and 20 MJ/

m2

 in the early summer months (Fig. 14). On a clear day

in June, solar radiation can exceed 30 MJ/m2

; it is

typically about 10 MJ/m2

 in winter. On cloudy and

overcast days, solar radiation is generally 1 to 2 MJ/m2

.

Solar radiation varies among years for a given month

with most variability occurring during the summer

(Table 20). The highest annual solar radiation (5,219

MJ/m2

) was recorded in 1997; the lowest on record

(3,765 MJ/m2

) was recorded in 2000.

Humidity

The humidity of the air is an important meteorological

variable but also one that is difficult to measure. It can

be expressed in several meaningful ways. The amount of

water vapor in the air is reported here as vapor pressure

(kPa). Vapor pressure does not vary with temperature, so

it changes little over one day and only as the amount of

water vapor in the air changes.

Hygrothermographs at HBEF weather stations measure

both humidity and air temperature. Since 1981, solidstate humidity sensors have been part of the automatic

HQ weather station and have recorded humidity on an

hourly basis. The average monthly vapor pressure at

HBEF is obtained by combining data from

hygrothermographs during the 1960’s and 1970’s with

data from the sensor installed in 1981 (Figure 15).

Figure 14.—Mean monthly solar

radiation at Headquarters (1958-2000).

Vertical bars show the standard error.

Figure 15.—Average vapor pressure by

month at Headquarters (1966-2000).
16

Wind

Windspeed and direction have been measured at HQ

since 1965 by an anemometer mounted 3 m above the

ground. The HQ anemometer is in a sheltered location

with surrounding trees, a nearby building, and moderate

topographic relief. Until 1981, every mile of wind

movement caused a tick mark on a strip-chart recorder,

and wind direction, as N, S, E, W, or a combination,

was recorded continuously. Only a portion of these data

have been analyzed. Since 1981 windspeed and direction

have been measured at the automatic weather station at

HQ. This record has both short and long gaps due to

equipment failures and related poblems.

Monthly average daily wind movement calculated from a

patchy database from 1966 to 1981 and a continuous

database from 1982 to 2000 is shown in Figure 16.

Dividing these values by 24 gives the average speed in

km/hr. This value is somewhat misleading because

windspeeds usually are considerably greater during the

day than at night. A more accurate daytime speed is

obtained by dividing by 12.

February is the windiest month, averaging 112 km/d, or

about 3m/s during the daytime. August is the calmest

month, averaging 69 km/d. At HBEF, windspeed 3 m

above the ground at HQ probably is lower than that at 3

m above the forest canopy.

The data on wind direction at HBEF are continuous

from 1982 to the present. Data from earlier years are

available on strip charts but have been analyzed only for

short periods. November through April is the windiest

period of the year as winds from the north and

northwest winds are dominant. From May through

October, west winds become somewhat more prevalent

than north winds. South winds occur fairly frequently

but usually are light. East winds are infrequent.

Soil Temperature

Soil temperature has been measured at several locations

at HBEF. Weekly values from a location 300 m

southwest of the streamgage for Watershed 4 are

available from 1959 to 1998. The soil at this location is

Berkshire fine sandy loam, which is a coarse loamy,

mixed, frigid Typic Haplorthod. Soil temperature is

measured at depths of 3, 8, 15, 30, 61, and 91 cm below

the litter layer (Oi horizon) using thermistor Colman

fiberglass soil-moisture sensors. These sensors are stable

and accurate to +/-1o

C.

Variation in soil temperature by day of the year is shown

for depths of 8 cm (Fig. 17) and 61 cm (Fig. 18). Near

the soil surface in winter, soil temperatures are below

freezing only when the soil freezes. Soil frost generally

occurs during winters when snow cover is thin or late in

developing. Warming at 8 cm is rapid in April after

snowmelt because the sun is high and leaves are not fully

developed. Soil temperatures reach a maximum in late

July and August. Average maximum soil temperatures,

about 16o

C at a depth of 8 cm, are slightly lower than

the average daily mean air temperature (about 18 oC).

Soil temperature varies much less at a depth 61 cm. At

Figure 16.—Average daily wind

movement at Headquarters by month

(1966-2000 with some gaps).
17

Figure 17.—Soil Temperature at depth of 8 cm by day of year (1959-98).

Figure 18.—Soil Temperature at depth of 61 cm by day of year (1959-98).
18

greater depths, the soil warms more slowly and reaches a

summer maximum of 13oC at 61 cm. Around mid-April

and in early October, the soil is isothermal, that is, the

temperature is the same at all depths. In autumn, cooling

is slower at greater depths.

Conclusion

Commitment to long-term hydrometeorlogic data

collection at the HBEF by the Northeastern Research

Station has resulted in a unique resource. These longterm data are used by scientists, resource managers, and

students interested in understanding and explaining

changes in the environment. Significant effort is

expended in maintaining the integrity of ongoing data

collection and accommodating new technology. It is this

outstanding effort that has made Hubbard Brook a

valued and dependable contributor to the knowledge

base required to explain ecosystem processes.

Acknowledgment

Ian Halm, Ralph Perron, Don Buso, Vinnie Levasseur,

and Don Mower assisted tirelessly in data collection in

all weather conditions. The ideas and commitment they

bring to the job improve data collection techniques and

make gathering data in mountainous conditions at all

times of the year more manageable. Bob Smith reworked

antiquated computer programs to accommodate the new

millennium and changes in methods and technology.

Without his programming, the processing and

organization of 45 years of hydrometeorological data

would be an insurmountable task.

Literature Cited

Federer, C.A.; Flynn, L.D.; Martin, C.W.; Hornbeck,

J.W.; Pierce R.S. 1990. Thirty years of

hydrometeorologic data at the Hubbard Brook

Experimental Forest, New Hampshire. Gen. Tech.

Rep. NE-141. Radnor, PA: U.S. Department of

Agriculture, Forest Service, Northeastern Forest

Experiment Station. 44 p.

Hornbeck, J. W.; Martin, C.W.; Eagar, C. 1997.

Summary of water yield experiments at Hubbard

Brook Experimental Forest, New Hampshire.

Canadian Journal of Forest Research. 27: 2043-2052.

Linsley, R.K., Jr.; Kohler, M.A.; Paulhus, J.L.H. 1958.

Hydrology for Engineers. New York: McGraw-Hill.

340 p.

Martin, C.W.; Hornbeck, J.W.; Likens, G.E.; Buso,

D.C. 2000. Impacts of intensive harvesting on

hydrology and nutrient dynamics of northern

hardwood forests. Canadian Journal of Fisheries and

Aquatic Sciences. 57 (Suppl. 2): 19-29.

Reinhart, K.G.; Pierce, R.S. 1964. Steam-gaging

stations for research on small watersheds. Agric.

Handb. 268. Washington, DC: U.S. Department of

Agriculture. 37 p.

Sartz, R.S.; Trimble, G.R., Jr. 1956. Snow storage and

melt in a northern hardwoods forest. Journal of

Forestry. 54: 499-502.
19

Table 2.—Monthly precipitation (mm) for Watershed 3 reported as total weighted average of daily precipitation for

several standard gages each month; the weighting factor for each gage is the fraction of watershed area nearest that gage;

the average and standard deviation are estimated from 45 years of data; annual total is monthly sum

Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Total

56 71 98 145 107 142 94 228 112 173 62 94 127 1453

57 71 64 48 61 87 143 137 19 78 110 179 221 1218

58 202 82 56 115 104 60 125 57 113 98 96 54 1161

59 137 91 80 80 52 113 71 142 64 304 220 125 1479

60 114 125 97 121 133 93 180 28 142 130 89 73 1325

61 32 99 63 124 85 99 86 54 49 56 113 119 979

62 89 108 65 112 100 53 86 98 93 253 79 95 1230

63 99 79 117 144 77 65 74 150 39 31 205 71 1151

64 121 43 144 114 110 60 118 150 37 50 114 115 1175

65 61 100 28 82 24 108 91 89 195 124 147 72 1121

66 63 60 115 66 91 106 97 194 116 83 134 100 1224

67 57 99 53 132 108 79 112 137 135 121 113 150 1297

68 73 62 97 113 202 162 62 57 67 75 128 188 1285

69 72 179 83 88 110 90 187 152 45 63 139 194 1403

70 26 99 106 99 93 96 62 155 139 100 91 135 1201

71 73 119 95 50 110 68 143 114 77 103 101 120 1173

72 69 81 169 88 88 120 158 159 49 95 165 182 1424

73 128 88 93 102 164 354 85 115 149 94 133 287 1793

74 115 88 123 129 162 123 102 130 167 47 118 108 1410

75 117 81 143 69 38 167 181 95 167 143 134 114 1449

76 146 123 110 91 187 113 107 136 133 204 61 105 1516

77 77 74 166 109 39 123 70 99 198 195 99 140 1388

78 230 27 71 76 104 142 52 88 35 93 63 105 1086

79 226 56 142 129 155 52 72 131 124 147 118 80 1433

80 54 38 136 129 58 77 88 85 132 112 126 67 1101

81 24 259 43 120 128 167 234 139 150 197 65 139 1665

82 119 74 112 106 29 157 70 70 110 51 146 71 1114

83 123 84 139 118 190 33 75 150 46 97 204 195 1452

84 53 118 121 130 302 176 139 31 38 79 118 98 1404

85 60 88 92 64 104 118 54 84 146 114 131 83 1137

86 207 75 125 61 114 85 140 168 98 63 133 105 1373

87 90 11 164 72 81 194 77 109 154 106 115 61 1235

88 62 81 48 99 85 70 110 133 71 55 131 65 1010

89 72 69 87 93 192 148 76 136 131 188 161 65 1419

90 147 87 72 98 160 205 77 311 114 191 100 168 1729

91 83 49 114 90 89 49 108 265 112 159 89 112 1319

92 89 99 119 90 61 76 159 161 128 76 162 58 1280

93 98 82 140 119 71 86 116 114 127 99 146 90 1288

94 140 46 143 111 100 109 129 95 131 31 85 77 1195

95 115 87 77 62 94 48 167 144 92 236 154 100 1374

96 212 109 53 245 120 169 226 22 80 159 122 209 1724

97 129 86 146 63 109 78 169 110 71 42 165 74 1242

98 170 74 118 62 93 309 110 93 83 121 108 61 1401

99 178 50 130 21 135 83 105 109 321 79 105 57 1373

00 109 112 112 224 146 92 94 106 92 80 102 143 1411

Avg. 107 87 104 102 112 116 116 118 111 114 124 115 1325

SD 53 40 36 40 53 64 45 55 55 62 36 50 185

Appendix
20

Table 3.—Monthly precipitation (mm) for Watershed 6 reported as total weighted average of daily precipitation for

several standard gages each month; the weighting factor for each gage is the fraction of watershed area nearest that gage;

average and standard deviation are estimated from 37 years of data; annual total is monthly sum

Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Total

64 117 50 147 110 115 59 126 154 39 54 120 117 1207

65 66 103 29 83 26 115 99 84 193 127 153 78 1157

66 72 67 129 70 94 118 100 200 118 87 154 108 1314

67 63 111 57 149 117 82 116 134 142 125 118 160 1374

68 77 69 103 126 219 160 55 53 77 80 138 212 1369

69 84 182 102 104 103 93 203 147 48 64 156 206 1491

70 27 102 119 103 93 100 66 162 140 106 97 149 1263

71 89 136 107 57 120 70 151 123 75 109 114 119 1270

72 77 83 180 93 87 129 158 167 48 94 176 201 1493

73 121 75 97 118 181 373 87 115 142 99 129 287 1824

74 115 94 136 145 166 121 111 138 172 48 118 111 1475

75 121 93 168 68 39 171 182 96 174 143 158 126 1540

76 161 145 124 93 196 113 110 145 138 206 77 114 1622

77 91 86 168 117 37 133 73 96 198 193 124 153 1470

78 250 32 83 85 113 148 53 96 36 95 70 115 1176

79 232 61 140 153 162 47 82 132 128 163 128 79 1506

80 53 41 147 135 58 81 92 92 136 124 130 77 1166

81 26 298 44 122 135 150 234 151 160 197 72 149 1736

82 135 78 118 112 32 163 77 72 114 52 150 72 1174

83 134 95 153 128 199 34 77 155 47 98 217 221 1558

84 60 130 135 149 314 179 143 37 39 88 120 122 1515

85 74 93 125 74 106 129 57 90 156 116 145 93 1258

86 224 83 135 64 133 89 151 176 97 65 142 119 1479

87 108 14 178 81 92 204 75 114 166 113 123 72 1338

88 68 94 53 108 101 68 115 147 75 58 153 67 1107

89 75 71 90 107 209 161 72 137 130 198 167 75 1492

90 159 98 86 106 164 202 79 329 117 198 107 174 1819

91 95 54 122 100 92 52 110 285 117 160 90 122 1399

92 95 107 126 98 62 75 162 149 138 75 167 61 1313

93 107 95 143 133 68 94 121 127 134 101 151 104 1377

94 149 51 156 118 99 107 128 101 139 30 94 91 1263

95 126 91 85 66 97 46 171 151 94 268 179 110 1484

96 223 121 59 264 122 174 242 21 80 163 136 220 1824

97 137 92 160 71 114 80 174 121 74 46 178 83 1328

98 178 73 122 67 95 325 108 103 88 123 132 62 1475

99 193 59 149 23 143 79 121 114 357 83 116 59 1495

00 115 114 114 239 157 92 103 115 102 79 111 159 1500

Avg. 116 93 119 109 121 125 118 130 120 114 133 126 1423

SD 56 47 38 45 59 71 48 57 60 54 32 54 187
21

Table 4.—Monthly precipitation (mm) for Watershed 7 reported as total weighted average of daily precipitation for

several standard gages each month; the weighting factor for each gage is the fraction of watershed area nearest that gage;

average and standard deviation are estimated from 36 years of data; annual total is monthly sum

Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Total

65 70 108 33 82 23 122 94 79 178 136 145 72 1142

66 89 68 127 68 105 107 89 170 122 86 159 107 1294

67 52 96 56 136 124 104 117 136 141 121 116 147 1347

68 69 65 107 117 172 170 33 44 99 77 148 200 1298

69 86 192 100 103 110 100 201 154 43 63 190 226 1568

70 28 114 118 108 93 98 66 141 137 108 92 147 1250

71 90 142 115 56 119 55 155 120 81 112 113 125 1284

72 67 97 179 95 98 127 152 154 46 98 191 197 1501

73 113 73 100 139 202 347 80 111 139 102 117 290 1815

74 116 98 138 145 174 124 135 145 175 48 125 114 1535

75 123 96 158 74 55 159 192 95 176 143 146 123 1541

76 156 130 120 96 202 109 118 168 133 217 73 103 1625

77 98 85 165 115 36 140 63 96 206 200 128 156 1488

78 249 29 84 93 122 154 69 85 34 99 69 106 1194

79 232 58 136 153 173 39 76 134 124 165 124 76 1490

80 52 37 161 158 64 94 81 108 147 133 128 74 1235

81 23 314 41 127 148 169 230 149 172 190 74 124 1763

82 147 78 119 102 36 165 71 83 112 52 139 71 1176

83 130 98 167 147 196 40 71 185 51 93 236 207 1620

84 64 125 129 165 316 185 146 34 42 80 136 132 1554

85 60 87 135 74 104 115 62 87 177 120 161 93 1275

86 232 78 139 63 108 94 155 213 94 62 160 136 1533

87 114 13 165 85 97 218 83 98 170 124 127 82 1375

88 70 104 55 137 113 59 113 164 69 60 177 62 1182

89 77 80 91 98 210 188 66 141 134 206 178 64 1532

90 165 96 82 119 176 210 56 322 120 191 101 195 1831

91 95 52 122 113 97 51 110 269 122 152 86 111 1381

92 94 99 123 94 65 72 194 140 145 67 156 65 1312

93 107 110 138 144 71 88 121 147 124 110 150 103 1412

94 160 50 164 110 109 121 143 97 154 31 99 111 1349

95 135 92 86 66 99 47 147 170 91 281 188 113 1514

96 208 113 65 267 140 167 262 17 74 204 138 220 1873

97 148 81 159 69 119 80 204 149 79 51 190 89 1418

98 168 72 139 59 102 319 155 110 85 126 139 72 1545

99 202 73 165 22 138 72 130 84 312 85 126 69 1478

00 118 97 116 244 138 87 117 109 93 81 113 150 1463

Avg. 117 94 119 112 124 128 121 131 122 119 137 126 1450

SD 57 52 36 41 58 63 56 60 45 59 39 55 188
22

Table 5.—Annual precipitation (mm) by watershed. Data are from annual total column in Tables 2,

3, and 4 and are similarly calculated for other watersheds

Watershed

Year 1 2 3 4 5 6 7 8 9

1956 1453 - ---- - --

1957 1218 1220 ---- - --

1958 1155 1167 1161 - - - - - -

1959 1472 1483 1479 - - - - - -

1960 1316 1321 1325 1327 - - - - -

1961 968 979 979 975 - - - - -

1962 1221 1232 1230 1234 - - - - -

1963 1134 1139 1151 1153 - - - - -

1964 1178 1175 1175 1180 1187 1207 - - -

1965 1123 1115 1121 1137 1147 1157 1142 - -

1966 1229 1222 1224 1261 1284 1314 1294 - -

1967 1320 1315 1297 1351 1357 1374 1347 - -

1968 1270 1269 1285 1302 1334 1369 1298 - -

1969 1374 1368 1403 1412 1443 1491 1568 1549 -

1970 1193 1185 1201 1216 1231 1263 1250 1255 -

1971 1172 1164 1173 1208 1228 1270 1284 1275 -

1972 1436 1431 1424 1412 1439 1493 1501 1495 -

1973 1806 1804 1793 1780 1785 1824 1815 1824 -

1974 1413 1407 1410 1428 1437 1475 1535 1546 -

1975 1433 1422 1449 1411 1432 1540 1541 1549 -

1976 1518 1512 1516 1528 1534 1622 1625 1626 -

1977 1389 1382 1388 1394 1404 1470 1488 1495 -

1978 1093 1088 1086 1114 1124 1176 1194 1181 -

1979 1425 1417 1433 1460 1462 1506 1490 1497 -

1980 1094 1088 1101 1118 1123 1166 1235 1218 -

1981 1641 1632 1665 1703 1702 1736 1763 1766 -

1982 1100 1089 1114 1151 1149 1174 1176 1185 -

1983 1447 1437 1452 1513 1522 1558 1620 1621 -

1984 1405 1397 1404 1467 1480 1516 1554 1558 -

1985 1137 1128 1137 1203 1217 1258 1275 1283 -

1986 1375 1364 1373 1446 1450 1479 1533 1516 -

1987 1228 1223 1235 1284 1298 1338 1375 1378 -

1988 1008 1004 1010 1060 1073 1107 1182 1158 -

1989 1421 1411 1419 1464 1464 1492 1532 1528 -

1990 1728 1719 1729 1787 1796 1819 1831 1853 -

1991 1329 1324 1319 1375 1383 1399 1381 1388 -

1992 1260 1255 1280 1308 1310 1313 1312 1325 -

1993 1292 1290 1288 1348 1365 1377 1412 1402 -

1994 1188 1184 1195 1239 1246 1263 1350 1339 -

1995 1376 1364 1374 1453 1469 1484 1514 1505 1527

1996 1721 1705 1724 1810 1814 1824 1873 1857 1884

1997 1238 1227 1242 1305 1313 1328 1418 1414 1409

1998 1402 1398 1401 1448 1459 1475 1545 1551 1584

1999 1382 1375 1373 1447 1467 1496 1478 1487 1511

2000 1415 1411 1411 1464 1475 1500 1463 1452 1466

Avg. 1322 1315 1324 1358 1389 1423 1450 1471 1564

SD 184 183 186 192 185 187 183 189 168

n 45 44 43 41 37 37 36 35 6
23

Table 6.—The 20 largest precipitation events for

Watershed 3, 1958-2000; storm periods are

consecutive days with precipitation; total precipitation

during a storm period is recorded for each event

Event Millimeters

Jun 27 - Jul 1, 1973 211.6

Oct 23 - Oct 26, 1959 184.9

Oct 5 - Oct 10, 1962 182.9

Jan 16 - Jan 20, 1996 174.3

Aug 6 - Aug 8, 1990 171.2

May 28 - Jun 2, 1984 162.1

Jul 26 - Aug 2, 1969 151.1

Jul 9 - Jul 15, 1975 140.4

Jan 25 - Jan 28, 1986 132.2

Jul 12 - Jul 16, 1996 125.4

Mar 30 - Apr 6, 1960 125.0

Sep 8 - Sep 13, 1987 116.8

Mar 30 - Apr 1, 1987 111.9

Nov 5 - Nov 17, 1985 110.4

May 23 - May 30, 1979 110.2

Aug 19 - Aug 22, 1991 105.3

Feb 24 - Feb 26, 1969 102.6

Oct 20 - Oct 24, 1996 100.4

Jul 3 - Jul 15, 1992 99.0
24

Table 7.—Monthly streamflow (mm) for Watershed 3; streamflow reported in mm to make it comparable among

watersheds of different areas; streamflow rate is divided by watershed area to give units of depth per unit time

over entire watershed area; average and standard deviation are estimated from 43 years of data; annual total is

monthly sum

Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Total

1958 38 18 40 291 89 25 7 1 3 13 28 15 567

1959 48 19 44 295 30 15 4 3 7 176 198 78 918

1960 48 48 64 310 88 18 19 3 5 64 61 24 752

1961 9 42 66 188 66 24 7 1 1 1 10 20 436

1962 32 10 64 268 85 4 1 2 2 110 85 36 699

1963 12 9 65 321 103 6 1 3 1 1 82 58 663

1964 56 19 92 253 71 3 6 10 1 4 43 71 630

1965 24 28 37 178 33 13 2 1 35 80 88 27 547

1966 39 22 117 180 101 34 4 20 19 47 120 54 757

1967 23 15 45 272 119 19 8 11 27 96 71 75 781

1968 17 36 184 199 124 103 18 1 2 3 24 53 763

1969 23 18 33 435 121 17 51 50 6 15 116 114 999

1970 23 71 25 256 75 6 7 10 33 83 70 39 698

1971 20 31 33 271 159 10 6 11 14 48 20 52 676

1972 32 22 93 200 206 43 56 40 6 26 99 62 886

1973 101 84 209 112 122 245 72 8 34 41 103 266 1396

1974 46 37 100 239 140 49 17 10 51 38 82 79 890

1975 25 21 118 201 62 94 53 4 56 138 118 49 940

1976 62 83 184 186 159 13 11 35 29 151 64 45 1022

1977 12 9 258 149 24 20 3 3 42 187 63 73 844

1978 149 20 24 219 100 77 1 1 1 3 6 11 614

1979 76 20 305 201 116 18 4 4 20 98 111 64 1036

1980 30 4 64 217 60 11 2 2 5 33 70 51 548

1981 8 277 57 113 103 69 94 80 43 164 56 30 1094

1982 37 32 60 363 43 38 7 2 4 10 84 77 756

1983 82 67 121 151 162 35 1 3 1 6 102 160 889

1984 16 115 64 259 235 95 65 1 1 3 38 78 971

1985 23 68 98 112 67 21 3 1 17 75 100 44 628

1986 175 24 180 145 75 19 19 77 37 52 90 66 961

1987 20 11 248 102 49 95 21 7 46 64 79 54 797

1988 19 29 78 161 63 7 7 7 11 11 87 23 502

1989 12 17 94 201 166 79 6 13 19 146 137 19 909

1990 69 66 190 132 129 93 30 183 14 156 89 149 1302

1991 32 26 129 130 52 6 4 71 19 137 64 74 743

1992 73 16 118 196 60 19 25 45 64 53 160 41 870

1993 42 15 121 259 31 26 5 9 19 47 144 82 801

1994 23 27 52 334 82 17 9 11 20 16 35 87 714

1995 111 16 118 61 64 16 14 61 4 152 159 21 797

1996 234 106 82 277 155 65 126 6 2 42 129 191 1414

1997 31 39 70 283 122 16 43 4 5 9 70 21 713

1998 95 48 232 104 58 204 40 8 13 55 77 48 981

1999 96 38 169 120 82 12 8 7 154 75 100 47 910

2000 39 35 200 257 123 22 6 16 16 27 66 127 932

Avg. 51 41 110 214 97 42 21 20 21 64 84 66 831

SD 46 45 70 79 47 50 27 33 27 56 41 49 213
25

Table 8.—Annual streamflow (mm) by watershed; average and standard deviation calculated

using number of years available for each watershed; T = treated watersheds

Watershed

Year 1 2 3 4 5 6 7 8 9

1956 942 - - - - - - - -

1957 732 - - - - - - - -

1958 590 645 567 - - - - - -

1959 947 1012 918 - - - - - -

1960 761 825 752 195 - - - - -

1961 458 470 436 495 - - - - -

1962 697 777 699 710 740 - - - -

1963 652 774 663 713 686 775 - - -

1964 653 712 630 713 683 704 - - -

1965 520 599T 547 583 624 581 504 - -

1966 746 1189T 757 826 826 845 851 - -

1967 758 1132T 781 839 815 834 816 - -

1968 771 1057T 763 823 832 835 790 - -

1969 1046 1348T 999 1099 975 1070 1174 1106 -

1970 661 905T 698 727T 669 735 741 704 -

1971 641 801T 676 765T 659 718 780 737 -

1972 877 1006T 886 990T 903 948 995 936 -

1973 1403 1586T 1396 1589T 1428 1470 1408 1419 -

1974 887 998T 890 1021T 928 951 1004 993 -

1975 934 1086T 940 1085T 944 963 991 983 -

1976 1067 1143T 1022 1158T 1069 1074 1116 1110 -

1977 895 966T 844 971T 863 878 957 895 -

1978 650 722T 614 717T 635 683 757 701 -

1979 1052 1136T 1036 1085T 1035 1070 1088 1075 -

1980 560 585T 548 575T 554 578 693 655 -

1981 1098 1129T 1094 1117T 1059 1078 1208 1164 -

1982 756 803T 756 792T 718 743 785 774 -

1983 908 917T 889 916T 843T 894 980 962 -

1984 974 1001T 971 1003T 1129T 977 1063 1036 -

1985 640 635T 628 643T 704T 688 777 732 -

1986 958 988T 961 976T 957T 998 1024 988 -

1987 769 790T 797 804T 789T 839 919 902 -

1988 497 491T 502 520T 544T 574 673 644 -

1989 882 948T 909 918T 950T 949 994 965 -

1990 1245 1396T 1302 1333T 1349T 1357 1387 1360 -

1991 737 784T 743 759T 821T 776 812 798 -

1992 786 876T 870 860T 871T 863 893 858 -

1993 775 834T 801 841T 872T 873 921 872 -

1994 677 713T 714 749T 751T 763 881 835 -

1995 833 859T 797 847T 897T 910 916 899 859

1996 1429 1517T 1414 1455T 1483T 1479 1409 1394 1405

1997 713 734T 713 751T 801T 1288 853 809 798

1998 994 1054T 981 986T 989T 1055 1086 1057 1059

1999 896 962T 910 949T 961T 1017 947 933 933

2000 811T 998T 932 985T 985T 998 959 887 912

Avg. 828 928 831 875 881 917 949 943 994

SD 210 247 213 252 211 218 199 196 200

n 45 44 43 41 37 37 36 35 6
26

Table 9.—Monthly streamflow (mm) for Watershed 6; streamflow reported in mm to make it comparable among

watersheds of different areas; streamflow rate is divided by watershed area to give units of depth per unit time

over entire watershed area; average and standard deviation are estimated from 38 years of data; annual total is

monthly sum

Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Total

1963 14 11 68 383 124 9 2 5 1 2 100 57 775

1964 57 19 98 266 82 4 7 20 2 7 61 80 704

1965 27 31 38 179 40 15 5 1 46 77 92 31 581

1966 34 22 115 199 120 41 9 32 27 52 138 58 845

1967 26 16 43 270 136 24 13 14 36 101 77 79 834

1968 18 39 189 210 149 113 16 2 4 8 33 54 835

1969 26 19 32 449 143 21 68 54 7 17 119 116 1070

1970 25 67 28 267 82 9 10 15 35 77 80 41 735

1971 23 36 33 267 202 11 8 15 10 41 22 49 718

1972 33 22 99 213 219 56 60 48 8 28 101 61 948

1973 97 84 205 138 143 277 74 11 29 42 98 272 1470

1974 47 40 98 265 147 52 23 15 59 38 86 81 951

1975 28 22 124 208 73 94 60 7 60 120 112 55 963

1976 62 85 185 191 157 16 14 48 41 157 72 46 1074

1977 13 11 253 155 24 28 5 5 50 175 81 79 878

1978 163 24 28 220 125 84 2 2 1 8 11 15 683

1979 77 20 310 199 122 20 5 6 25 110 112 64 1070

1980 28 4 54 219 61 13 3 3 10 57 73 53 578

1981 9 285 63 107 104 58 85 80 49 158 53 29 1078

1982 36 29 55 351 46 44 8 3 7 14 76 72 743

1983 84 67 111 168 158 35 1 5 1 9 101 154 894

1984 16 110 60 285 227 99 63 1 1 5 44 68 977

1985 21 66 104 135 65 31 5 2 31 79 104 46 688

1986 174 26 177 146 92 20 28 87 39 54 86 69 998

1987 23 13 252 107 56 104 22 9 54 69 78 52 839

1988 19 30 79 175 78 8 9 12 17 14 109 24 574

1989 13 17 85 217 180 89 7 15 20 144 142 20 949

1990 68 67 208 141 133 93 25 199 16 166 94 148 1357

1991 33 24 123 148 55 8 5 86 23 135 63 73 776

1992 73 18 121 201 57 22 24 43 61 53 147 43 863

1993 45 15 119 286 32 33 7 19 31 57 143 86 873

1994 23 28 51 343 88 20 12 13 31 21 43 91 763

1995 112 18 128 67 70 17 18 64 7 196 189 24 910

1996 234 104 75 302 165 74 137 8 4 51 133 192 1479

1997 35 42 68 299 148 21 43 7 8 19 92 22 1288

1998 94 51 229 123 62 225 41 11 13 64 81 60 1055

1999 104 39 177 134 91 16 13 9 199 79 107 48 1017

2000 38 38 201 268 136 23 9 26 28 33 66 133 998

Avg. 54 44 118 218 110 51 25 26 29 67 90 72 917

SD 49 47 72 82 51 57 29 37 34 54 36 50 218
27

Table 10.—Monthly streamflow (mm) for Watershed 6; streamflow reported in mm to make it comparable among

watersheds of different areas; streamflow rate is divided by watershed area to give units of depth per unit time

over entire watershed area; average and standard deviation are estimated from 36 years of data; annual total is

monthly sum

Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Total

1965 35 25 17 147 30 6 2 48 97 74 22 504

1966 33 15 74 130 248 50 6 14 34 64 127 57 851

1967 15 12 15 175 247 41 16 17 39 110 60 68 816

1968 13 27 128 272 112 104 17 1 4 8 41 62 790

1969 18 13 15 377 296 26 78 58 4 11 159 120 1174

1970 20 59 16 266 138 9 11 9 29 90 65 29 741

1971 13 23 25 129 409 13 7 17 20 65 25 35 780

1972 26 18 71 89 404 64 67 39 6 34 115 62 995

1973 79 66 150 259 165 228 61 7 29 47 94 223 1408

1974 31 30 72 291 182 50 47 23 84 46 85 63 1004

1975 18 14 85 111 233 117 61 4 80 121 108 40 991

1976 47 61 126 284 171 16 11 98 36 170 58 36 1116

1977 9 6 194 263 29 36 5 11 73 202 67 62 957

1978 142 21 15 136 302 97 2 2 1 7 14 18 757

1979 77 16 200 280 168 20 2 4 29 129 115 47 1088

1980 16 1 30 256 98 31 5 5 37 95 74 45 693

1981 6 271 54 174 123 83 97 95 71 163 49 22 1208

1982 26 27 28 301 135 63 14 3 8 24 93 62 785

1983 63 51 97 211 207 39 2 6 2 13 149 139 980

1984 13 69 38 347 283 110 69 2 1 3 55 74 1063

1985 21 49 52 203 88 28 8 2 61 105 123 37 777

1986 151 20 122 226 82 19 32 133 43 46 90 61 1024

1987 18 8 181 206 69 139 21 5 55 90 80 49 919

1988 14 25 41 240 118 10 6 19 23 16 143 18 673

1989 8 10 60 159 264 109 9 20 29 176 136 15 994

1990 48 54 168 220 160 112 20 197 10 166 84 147 1387

1991 24 11 82 212 63 9 4 103 38 138 62 65 812

1992 62 13 86 173 108 40 54 54 75 52 143 35 893

1993 33 11 64 339 62 39 6 40 40 79 143 65 921

1994 17 20 28 309 184 29 21 25 63 30 47 108 881

1995 119 14 88 100 90 22 8 86 5 207 162 15 916

1996 167 80 30 281 270 65 166 8 2 87 95 159 1409

1997 28 28 52 185 283 29 72 16 15 23 108 16 853

1998 79 37 181 193 73 210 60 11 16 82 65 81 1086

1999 90 27 103 192 133 10 9 3 159 83 101 37 947

2000 28 22 116 338 144 23 10 36 30 41 62 108 959

Avg. 45 35 81 226 175 59 30 33 36 81 91 64 949

SD 42 44 55 73 93 53 35 44 32 58 38 46 199
28

Table 11.—Twenty hightest instantaneous streamflows, cubic square meters

(csm) and liters per second per ha (Ls-1ha-1) for Watershed 3, 1957-2000, and

associated storm precipitation, in mm

Peak discharge

Date csm Ls-1ha-1 Storm precipitation

Oct 24, 1959 394.3 43.1 Oct 23 - 26, 1959 184.9

Mar 31,1987 337.2 36.9 Mar 30 - Apr 1, 1987 111.9

Jan 19,1996 308.1 33.7 Jan 19, 1996 63.1

Oct 9,1977 256.3 28.0 Oct 8 - 9, 1977 92.8

Feb 11,1981 227.2 24.8 Feb 11 - 12, 1981 65.2

Jan 27,1986 203.4 22.2 Jan 25 - 28, 1986 132.2

Dec 21,1973 178.5 19.5 Dec 20 - 21, 1973 88.9

Apr 5,1984 159.2 17.4 Apr 5 - 8, 1984 70.8

Jan 9,1978 154.3 16.9 Jan 6 - 11, 1978 98.9

Oct 20,1975 147.6 16.1 Oct 15 - 20, 1975 87.5

Mar 13,1977 147.4 16.1 Mar 13 - 14, 1977 62.3

Jun 16,1998 146.7 16.0 Jun 12 - 18, 1998 201.3

Jun 29,1973 145.2 16.0 Jun 27 - Jul 1, 1973 211.6

Oct 20,1989 141.3 15.4 Oct 16 - 22, 1989 113.6

Aug 11,1990 131.4 14.4 Aug 6 - 11, 1990 253.3

Nov 26,1979 130.5 15.9 Nov 24 - 28, 1979 69.7

Apr 1,1976 128.1 14.0 Apr 1 - 3, 1958 45.8

Oct 21,1995 126.5 13.8 Oct 21 - 22, 1995 80.2

Apr 10,1980 115.9 12.7 Apr 9 - 16, 1980 79.5

Nov 3, 1966 115.7 12.6 Nov 2 - 3, 1966 79.8
29

Table 12.—Highest instantaneous streamflow in

each year for Watershed 3, in cubic square meters

(csm) and liters per second per ha (Ls-1ha-1)

Peak discharge

Date csm Ls-1ha-1

Jul 14, 1956 109.6 12.0

Dec 21, 1957 129.1 14.1

Apr 17, 1958 55.3 6.0

Oct 24, 1959 394.3 43.1

Mar 31, 1960 72.6 7.9

Apr 23, 1961 46.0 5.0

Apr 7, 1962 86.1 9.4

Apr 30, 1963 54.1 5.9

Apr 14, 1964 95.3 10.4

Apr 16, 1965 38.1 4.2

Nov 3, 1966 115.7 12.6

Apr 3, 1967 85.6 9.4

Apr 25, 1968 89.7 9.8

Jul 29, 1969 106.4 11.6

Apr 24, 1970 71.5 7.8

Oct 10, 1971 42.7 4.7

Aug 27, 1972 115.2 12.6

Dec 21, 1973 178.5 19.5

Dec 8, 1974 72.0 7.9

Oct 20, 1975 147.6 16.1

Apr 1, 1976 128.1 14.0

Oct 9, 1977 256.4 28.0

Jan 9, 1978 154.3 16.9

Nov 26, 1979 130.5 14.3

Apr 10, 1980 115.9 12.7

Feb 11, 1981 227.2 24.8

Apr 27, 1982 100.8 11.0

Feb 3, 1983 77.9 8.5

Apr 5, 1984 159.2 17.4

Sep 27, 1985 50.8 5.6

Jan 27, 1986 203.4 22.2

Mar 31, 1987 337.2 36.9

Mar 27, 1988 31.6 3.5

Oct 20, 1989 141.3 15.4

Aug 11, 1990 131.4 14.4

Aug 8, 1991 75.8 8.3

Mar 3, 1992 85.6 9.4

Nov 28, 1993 107.0 11.7

Apr 16, 1994 62.4 6.8

Oct 21, 1995 126.5 13.8

Jan 19, 1996 308.1 33.7

Nov 2, 1997 37.3 4.1

Jun 16, 1998 146.7 16.0

Sep 16, 1999 65.4 7.1

Dec 17, 2000 217.0 23.7

Apr 22, 2001 64.9 7.1

Apr 13, 2002 170.0 18.6

Table 13.—Annual precipitation (mm), streamflow (mm)

and evapotranspiration (precipitation minus streamflow)

for Watershed 3 by water year (beginning June 1); average

and standard deviation are calculated from 43 years of data

Water year Precipitation Streamflow Evapotranspiration

1958-59 1042 529 513

1959-60 1630 1039 590

1960-61 1137 567 571

1961-62 1050 524 526

1962-63 1274 750 524

1963-64 1167 644 523

1964-65 939 439 500

1965-66 1221 705 516

1966-67 1278 772 506

1967-68 1394 866 528

1968-69 1271 834 437

1969-70 1294 819 475

1970-71 1226 762 464

1971-72 1222 714 508

1972-73 1505 961 543

1973-74 1832 1332 500

1974-75 1242 755 487

1975-76 1658 1185 473

1976-77 1324 802 522

1977-78 1432 904 528

1978-79 1286 819 467

1979-80 1138 693 445

1980-81 1261 732 528

1981-82 1531 1070 461

1982-83 1328 803 525

1983-84 1522 997 525

1984-85 1087 648 439

1985-86 1311 860 451

1986-87 1210 792 418

1987-88 1190 717 474

1988-89 1150 642 508

1989-90 1469 1007 462

1990-91 1590 1084 506

1991-92 1354 837 517

1992-93 1331 875 456

1993-94 1317 851 466

1994-95 1090 566 524

1995-96 1678 1281 397

1996-97 1518 1105 413

1997-98 1225 705 520

1998-99 1399 950 449

1999-00 1562 1058 504

2000-01 1095 614 481

Avg. 1320 828 493

SD 195 202 41
30

Table 14.—Evaporation (annual precipitation minus streamflow) by watershed for years

beginning June 1, in mm; T = treated watersheds

Watershed

Year 1 2 3 4 5 6 7 8 9

1956-57 522 - - - - - - - -

1957-58 513 - - - - - - - -

1958-59 490 456 513 - - - - - -

1959-60 565 482 590 - - - - - -

1960-61 541 525 571 - - - - - -

1961-62 518 497 526 506 - - - - -

1962-63 505 370 524 483 - - - - -

1963-64 513 447 523 455 - - - - -

1964-65 501 443 500 456 413 481 - - -

1965-66 543 419T 516 498 524 524 501 - -

1966-67 545 102T 506 499 533 534 488 - -

1967-68 521 154T 528 488 503 521 507 - -

1968-69 392 79T 437 356 474 453 403 - -

1969-70 441 163T 475 425T 517 490 484 531 -

1970-71 496 231T 464 453T 533 501 471 508 -

1971-72 533 383T 508 420T 544 539 507 548 -

1972-73 561 443T 543 400T 523 535 488 509 -

1973-74 521 327T 500 328T 484 488 562 554 -

1974-75 459 311T 487 330T 445 500 513 543 -

1975-76 464 334T 473 333T 486 581 519 519 -

1976-77 461 394T 522 386T 497 552 494 539 -

1977-78 493 377T 528 409T 528 550 493 573 -

1978-79 455 375T 467 436T 504 511 487 487 -

1979-80 423 380T 445 432T 454 486 460 479 -

1980-81 502 473T 528 528T 566 576 496 525 -

1981-82 429 351T 461 440T 548 556 496 539 -

1982-83 510 492T 525 553T 612 597 532 567 -

1983-84 521 483T 525 549T 642 635 583 603 -

1984-85 431 418T 439 485T 361T 529 487 530 -

1985-86 437 406T 451 509T 466T 512 471 506 -

1986-87 454 409T 418 479T 488T 477 481 489 -

1987-88 473 465T 474 493T 518T 522 505 527 -

1988-89 527 495T 508 548T 514T 530 523 523 -

1989-90 502 382T 462 488T 461T 499 470 526 -

1990-91 536 437T 506 543T 512T 546 543 564 -

1991-92 559 460T 517 544T 506T 558 517 552 -

1992-93 496 432T 456 484T 466T 482 446 492 -

1993-94 526 446T 466 483T 487T 496 466 495 -

1994-95 508 512T 524 548T 518T 531 500 543 -

1995-96 366 273T 397 429T 410T 411 496 496 558

1996-97 406 317T 413 447T 393T 418 501 525 530

1997-98 517 479T 520 558T 528T 519 542 556 591

1998-99 452 375T 449 495T 514T 467 536 569 579

1999-00 595 475T 504 522T 519T 517 539 581 587
31

Table 15.—Average February soil-frost incidence and

thickness by year for snow course Stations 2 and 17;

incidence is percentage of frost occurrence at the 10

measurement sites at each station; thickness is average

depth of frost at the 10 sites within a station (cm) for

February

Station 2 Station 17

Year Incidence Depth Incidence Depth

Percent cm Percent cm

1956 20 5

1957 0 0

1958 0 0

1959 0 0

1960 7 3

1961 0 0

1962 0 0

1963 0 0

1964 0 0

1970 56 6 95 12

1971 0 0 43 1

1972 0 0 22 2

1973 0 0 0 0

1974 76 10 100 15

1975 0 0 50 1

1976 26 2 100 2

1977 0 0 91 1

1978 0 0 33 3

1979 0 0 30 1

1980 100 17 100 22

1981 0 0 93 7

1982 0 0 29 2

1983 100 8 100 12

1984 0 0 25 1

1985 0 0 60 2

1986 16 0 70 2

1987 0 0 13 1

1988 0 0 83 3

1989 84 2 100 10

1990 0 0 35 2

1991 55 7 100 9

1992 98 15 100 10

1993 81 17 100 14

1994 12 1 92 6

1995 50 3 87 3

1996 0 0 0 0

1997 0 0 0 0

1998 0 0 0 0

1999 0 0 0 0

2000 83 3 91 3
32

Table 16.—Average daily maximum air temperature (o

C) by month for Station 1 (1956-2000)

Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

1956 -3.0 -1.7 -0.6 6.2 14.3 21.7 21.6 22.4 15.4 13.9 6.2 -0.4

1957 -6.1 1.0 3.3 12.0 17.6 24.0 23.0 21.7 18.9 13.5 6.7 2.1

1958 -2.2 -4.4 4.3 10.4 15.1 18.0 22.4 23.3 17.4 11.0 5.1 -5.4

1959 -5.2 -3.8 1.7 9.1 19.8 19.4 25.6 23.7 19.6 10.9 4.1 -0.2

1960 -2.6 0.2 -0.6 9.0 18.4 21.1 23.2 23.3 18.6 10.6 6.5 -2.8

1961 -6.1 0.1 2.6 7.0 15.5 23.0 24.5 22.8 23.5 13.5 4.1 -2.3

1962 -4.9 -4.7 3.7 9.9 17.2 23.2 21.9 22.5 16.1 10.2 3.9 -1.8

1963 -3.7 -4.3 3.5 10.3 18.3 24.0 25.2 20.3 17.1 17.9 6.1 -6.6

1964 -1.8 -2.4 3.0 8.9 19.6 22.3 24.9 20.3 16.7 11.7 4.9 -1.8

1965 -6.2 -3.4 1.3 8.1 19.6 22.0 23.0 22.5 17.7 9.9 1.3 -1.4

1966 -3.8 -1.6 2.8 7.7 16.9 23.4 24.6 22.9 16.9 12.3 7.4 -0.5

1967 -0.8 -3.9 0.8 7.5 11.9 24.7 25.0 23.4 19.9 11.5 1.8 -0.6

1968 -4.9 -5.5 3.5 11.9 16.1 19.7 26.2 22.4 20.8 14.0 3.1 -3.1

1969 -1.6 -0.3 1.7 9.7 16.0 22.6 23.1 25.1 19.5 11.7 4.0 -3.4

1970 -9.2 -2.8 0.1 8.5 18.4 22.9 26.1 25.0 18.8 13.5 6.7 -3.6

1971 -5.8 -0.8 2.5 8.0 16.2 22.4 23.4 22.3 19.4 15.6 3.8 -1.0

1972 -2.6 -2.9 0.4 5.0 17.2 17.4 21.6 20.0 17.4 9.5 1.7 -2.0

1973 -2.0 -3.1 5.1 9.7 14.0 19.5 22.4 23.2 15.5 13.3 3.3 0.3

1974 -2.7 -2.7 0.6 8.8 12.6 21.2 23.1 22.7 16.7 8.8 5.6 0.4

1975 -1.8 -1.8 0.6 4.6 20.3 21.0 24.5 21.5 15.4 12.7 8.3 -2.6

1976 -5.8 0.7 3.1 12.1 16.1 23.5 22.5 21.5 17.5 9.9 1.4 -5.2

1977 -7.6 -3.2 6.0 11.1 20.4 19.4 23.7 22.6 15.9 11.8 6.2 -2.7

1978 -4.0 -4.0 1.6 6.5 18.7 20.6 23.9 22.6 17.5 11.3 5.8 -1.5

1979 -3.7 -6.6 4.2 8.0 16.8 22.5 25.6 21.5 18.9 10.7 7.5 -0.3

1980 -2.5 -4.2 2.3 8.8 18.0 19.6 23.4 22.8 17.7 9.4 2.1 -4.4

1981 -6.2 2.1 3.8 10.3 17.9 21.3 23.1 21.5 16.3 10.2 4.4 -1.9

1982 -8.0 -3.0 1.5 6.8 18.8 18.2 24.0 20.5 18.6 13.4 6.4 1.4

1983 -2.4 0.5 3.5 9.4 14.6 24.0 25.4 23.9 21.0 12.8 5.3 -3.1

1984 -4.2 3.1 -0.2 10.9 15.1 22.5 23.9 24.4 18.1 15.1 5.5 1.4

1985 -6.7 -0.9 4.4 10.1 17.4 18.6 24.8 22.3 19.2 12.8 4.2 -3.7

1986 -2.6 -3.0 3.8 13.1 18.0 19.2 21.0 20.9 17.1 12.0 3.4 -0.6

1987 -3.1 -3.5 4.6 11.4 17.5 20.8 24.1 21.5 17.4 12.3 4.8 -0.5

1988 -3.4 -1.2 2.8 8.4 17.8 20.8 25.0 24.0 18.2 9.6 5.6 -1.9

1989 -0.4 -2.2 2.2 7.0 17.3 20.0 23.1 19.8 19.6 14.4 4.3 -6.9

1990 1.4 1.0 5.3 10.2 15.5 21.2 25.1 24.4 17.6 13.5 6.2 1.5

1991 -3.8 0.5 3.1 12.9 19.3 22.6 23.8 23.6 17.3 13.4 5.9 -1.3

1992 -3.6 -1.9 2.2 7.5 19.2 21.0 18.8 20.2 17.1 8.7 4.0 0.5

1993 -2.8 -4.6 3.8 11.1 16.9 21.6 24.2 24.1 16.5 10.0 4.8 -0.8

1994 -7.9 -4.6 1.6 9.5 16.8 22.9 24.9 21.7 16.1 13.5 7.3 2.3

1995 -1.0 -3.3 3.7 7.0 16.0 24.3 24.9 23.5 17.0 14.1 1.7 -3.4

1996 -3.3 -2.7 3.2 9.0 16.0 21.1 22.6 24.3 18.5 11.2 2.1 1.0

1997 -3.5 0.8 0.2 8.3 12.9 22.6 24.5 23.1 18.1 12.2 2.7 -0.3

1998 -1.2 3.0 4.3 12.2 21.0 19.6 23.4 23.5 18.7 10.7 3.6 1.2

1999 -2.4 1.1 2.9 10.6 19.2 24.4 25.4 22.7 20.6 11.3 7.6 0.3

2000 -3.8 -0.1 6.9 8.7 17.3 21.1 22.8 21.6 17.6 12.9 4.5 -3.1

Avg. -3.8 -1.9 2.7 9.2 17.1 21.5 23.8 22.5 18.0 12.1 4.7 -1.5

SD 2.2 2.3 1.7 2.0 2.1 1.8 1.4 1.3 1.6 1.9 1.8 2.2
33

Table 17.—Average daily minimum air temperature (o

C) by month for Station 1 (1956-2000)

Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

1956 -10.1 -10.4 -9.5 -1.7 2.3 10.6 12.3 11.9 6.4 3.5 -2.5 -8.4

1957 -16.2 -10.1 -5.5 0.2 5.1 12.1 12.0 10.0 8.8 3.6 -1.1 -5.8

1958 -9.8 -14.2 -3.2 0.7 3.1 7.5 13.4 11.7 7.6 1.3 -2.8 -15.3

1959 -13.8 -16.9 -8.3 -0.6 6.7 10.3 14.6 13.6 10.0 3.5 -3.7 -6.5

1960 -10.2 -8.0 -9.5 0.0 8.2 10.2 12.8 12.5 8.8 1.5 -1.1 -12.7

1961 -15.8 -10.2 -6.8 -0.2 3.8 11.3 14.2 13.4 12.8 3.5 -2.2 -9.1

1962 -15.6 -14.6 -6.6 -1.4 5.2 11.6 10.9 12.2 7.0 1.2 -3.3 -11.8

1963 -12.1 -16.0 -6.7 0.8 4.8 11.7 14.0 11.0 5.3 4.2 -0.5 -14.6

1964 -10.4 -12.7 -5.7 -1.5 5.8 9.3 14.3 9.6 6.4 1.0 -3.1 -9.4

1965 -15.3 -14.3 -7.3 -1.5 5.0 9.1 10.9 12.0 7.6 0.8 -5.9 -8.3

1966 -13.4 -11.6 -6.2 -1.6 4.8 11.5 13.1 13.1 6.8 1.1 -0.4 -9.1

1967 -9.2 -15.7 -9.6 -2.9 1.6 13.3 15.3 13.4 8.5 1.9 -5.8 -8.8

1968 -15.4 -16.3 -6.0 0.5 4.3 11.4 15.2 11.9 11.1 5.3 -3.3 -10.9

1969 -10.4 -9.0 -6.7 -0.3 4.7 12.1 14.1 14.6 10.1 2.4 -2.6 -10.6

1970 -19.6 -14.6 -9.1 -1.6 6.4 11.0 15.6 13.8 9.7 4.4 0.1 -12.4

1971 -16.9 -10.2 -7.5 -1.0 6.9 12.3 14.0 13.8 11.9 7.5 -3.3 -8.9

1972 -11.6 -11.6 -7.1 -1.9 7.6 10.9 13.9 13.0 8.8 1.6 -3.2 -8.5

1973 -10.1 -11.8 -1.3 2.1 6.7 12.2 14.5 15.4 8.7 4.7 -2.8 -7.1

1974 -10.8 -12.5 -7.8 0.3 4.6 12.3 14.5 14.2 9.8 0.5 -1.8 -5.1

1975 -9.5 -10.0 -7.7 -2.6 9.8 12.1 14.7 12.2 7.3 2.8 0.2 -11.7

1976 -16.0 -10.2 -7.0 1.6 4.7 12.7 11.9 12.5 7.8 1.2 -5.1 -15.5

1977 -16.3 -11.2 -2.3 -0.2 6.2 10.2 12.4 12.7 6.6 1.5 -1.2 -10.3

1978 -13.2 -14.0 -7.8 -0.8 7.2 10.9 13.0 12.8 5.8 2.4 -3.0 -9.8

1979 -10.6 -14.5 -3.4 0.1 7.9 10.6 15.3 12.6 7.0 2.7 0.4 -8.3

1980 -11.5 -13.5 -7.0 0.1 5.7 9.0 13.6 13.3 6.9 1.0 -4.8 -16.3

1981 -17.5 -7.1 -5.2 0.1 5.8 9.9 12.9 11.6 7.9 1.0 -2.9 -7.7

1982 -17.5 -12.9 -7.7 -3.3 5.9 9.6 12.8 10.2 9.1 2.1 -1.2 -7.2

1983 -11.2 -8.7 -3.9 1.3 5.4 11.7 14.3 13.2 9.1 2.1 -1.1 -12.2

1984 -13.5 -5.8 -9.9 1.0 4.2 11.0 13.8 14.7 5.8 2.8 -3.2 -7.5

1985 -15.6 -10.5 -6.3 -0.6 5.4 9.6 13.3 12.9 9.9 3.3 -1.5 -11.7

1986 -12.2 -11.8 -5.9 2.0 6.9 8.7 12.7 12.1 7.5 1.9 -4.9 -8.0

1987 -11.1 -13.3 -4.7 1.5 5.6 11.8 14.0 10.6 9.1 1.8 -3.5 -6.9

1988 -12.8 -11.3 -6.9 0.6 7.8 9.3 15.5 14.5 7.9 2.1 -1.4 -10.6

1989 -10.0 -12.1 -8.1 -2.3 7.4 10.8 12.6 10.6 9.6 5.0 -3.7 -15.9

1990 -6.6 -9.4 -4.9 0.6 4.9 11.3 14.0 14.1 8.7 4.7 -1.6 -7.0

1991 -13.3 -9.6 -4.3 2.2 7.3 11.2 14.0 14.2 7.2 3.6 -0.9 -10.3

1992 -12.8 -11.4 -7.6 -2.0 5.6 9.4 9.2 11.0 7.5 0.9 -2.3 -6.8

1993 -10.7 -15.4 -7.1 0.1 5.3 10.0 13.5 13.4 7.6 -0.5 -4.0 -9.3

1994 -19.2 -14.8 -6.6 -0.1 4.8 12.0 15.1 11.3 8.0 3.2 -1.5 -6.7

1995 -7.8 -12.6 -4.4 -2.7 4.6 11.2 13.9 12.5 5.6 4.3 -5.8 -11.3

1996 -13.4 -12.1 -7.2 -0.5 4.5 11.6 13.3 13.4 9.7 1.0 -5.1 -5.1

1997 -13.5 -9.6 -9.0 -1.6 4.0 10.1 13.6 13.4 8.9 2.5 -4.5 -8.9

1998 -9.0 -6.4 -4.7 1.0 9.1 11.3 13.5 13.8 9.5 3.3 -1.1 -6.9

1999 -11.9 -7.9 -5.0 -0.1 7.4 12.1 14.7 12.4 11.5 1.0 -0.5 -6.5

2000 -13.2 -10.0 -2.8 0.1 6.1 11.3 12.1 12.1 7.0 3.0 -1.9 -12.0

Avg. -12.9 -12.0 -6.6 -0.4 5.6 10.8 13.5 12.6 8.3 2.5 -2.7 -9.7

SD 3.1 2.6 2.0 1.4 1.6 1.2 1.3 1.4 1.7 1.6 1.7 2.9
34

Table 18.—Average daily mean air temperature (o

C) by month for Station 1 (1956-2000)

Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

1956 -6.5 -6.0 -5.0 2.3 8.3 16.1 16.9 17.2 10.9 8.7 1.9 -4.4

1957 -11.2 -4.5 -1.1 6.1 11.4 18.1 17.5 15.9 13.9 8.6 2.8 -1.9

1958 -6.0 -9.3 0.6 5.5 9.1 12.8 17.9 17.5 12.5 6.2 1.2 -10.4

1959 -9.5 -10.4 -3.3 4.3 13.3 14.9 20.1 18.7 14.8 7.2 0.2 -3.4

1960 -6.4 -3.9 -5.0 4.5 13.3 15.7 18.0 17.9 13.7 6.0 2.7 -7.8

1961 -11.0 -5.0 -2.1 3.4 9.7 17.2 19.4 18.1 18.2 8.5 1.0 -5.7

1962 -10.3 -9.7 -1.5 4.3 11.2 17.4 16.4 17.4 11.6 5.7 0.3 -6.8

1963 -7.9 -10.2 -1.6 5.5 11.6 17.9 19.6 15.7 11.2 11.1 2.8 -10.6

1964 -6.1 -7.5 -1.4 3.7 12.7 15.8 19.6 15.0 11.6 6.4 0.9 -5.6

1965 -10.8 -8.8 -3.0 3.3 12.3 15.6 16.9 17.3 12.7 5.4 -2.3 -4.9

1966 -8.6 -6.6 -1.7 3.1 10.9 17.4 18.9 18.0 11.9 6.7 3.5 -4.8

1967 -5.0 -9.8 -4.4 2.3 6.8 19.0 20.2 18.4 14.2 6.7 -2.0 -4.7

1968 -10.2 -10.9 -1.3 6.2 10.2 15.6 20.7 17.2 16.0 9.7 -0.1 -7.0

1969 -6.0 -4.7 -2.5 4.7 10.4 17.4 18.6 19.9 14.8 7.0 0.7 -7.0

1970 -14.4 -8.7 -4.5 3.5 12.4 16.9 20.9 19.4 14.3 9.0 3.4 -8.0

1971 -11.4 -5.5 -2.5 3.5 11.6 17.4 18.7 18.1 15.7 11.6 0.3 -5.0

1972 -7.1 -7.3 -3.4 1.6 12.4 14.2 17.8 16.5 13.1 5.5 -0.8 -5.3

1973 -6.0 -7.5 1.9 5.9 10.4 15.9 18.4 19.3 12.1 9.0 0.3 -3.4

1974 -6.8 -7.6 -3.6 4.5 8.6 16.8 18.8 18.4 13.3 4.7 1.9 -2.4

1975 -5.7 -5.9 -3.6 1.0 15.1 16.6 19.6 16.9 11.4 7.8 4.3 -7.2

1976 -10.9 -4.8 -2.0 6.9 10.4 18.1 17.2 17.0 12.7 5.5 -1.9 -10.4

1977 -12.0 -7.2 1.9 5.5 13.3 14.8 18.1 17.7 11.3 6.7 2.5 -6.5

1978 -8.6 -9.0 -3.1 2.9 13.0 15.8 18.4 17.7 11.7 6.9 1.4 -5.7

1979 -7.2 -10.6 0.4 4.0 12.4 16.6 20.4 17.1 13.0 6.7 4.0 -4.3

1980 -7.0 -8.8 -2.4 4.5 11.9 14.3 18.5 18.1 12.3 5.2 -1.4 -10.4

1981 -11.9 -2.5 -0.7 5.2 11.9 15.6 18.0 16.6 12.1 5.6 0.8 -4.8

1982 -12.8 -8.0 -3.1 1.8 12.4 13.9 18.4 15.4 13.9 7.8 2.6 -2.9

1983 -6.8 -4.1 -0.2 5.4 10.0 17.9 19.9 18.6 15.1 7.5 2.1 -7.7

1984 -8.8 -1.4 -5.0 6.0 9.7 16.8 18.9 19.6 12.0 9.0 1.2 -3.1

1985 -11.2 -5.7 -1.0 4.8 11.4 14.1 19.1 17.6 14.6 8.1 1.4 -7.7

1986 -7.4 -7.4 -1.1 7.5 12.5 14.0 16.9 16.5 12.3 7.0 -0.8 -4.3

1987 -7.1 -8.4 -0.1 6.5 11.6 16.3 19.1 16.1 13.3 7.0 0.7 -3.7

1988 -8.1 -6.3 -2.0 4.5 12.8 15.1 20.3 19.3 13.1 5.9 2.1 -6.3

1989 -5.2 -7.2 -3.0 2.4 12.4 15.4 17.9 15.2 14.6 9.7 0.3 -11.4

1990 -2.6 -4.2 0.2 5.4 10.2 16.3 19.6 19.3 13.2 9.1 2.3 -2.8

1991 -8.6 -4.5 -0.6 7.5 13.3 16.9 18.9 18.9 12.3 8.5 2.5 -5.8

1992 -8.2 -6.7 -2.7 2.8 12.4 15.2 14.0 15.6 12.3 4.8 0.8 -3.1

1993 -6.8 -10.0 -1.7 5.6 11.1 15.8 18.9 18.8 12.1 4.8 0.4 -5.0

1994 -13.6 -9.7 -2.5 4.7 10.8 17.4 20.0 16.5 12.1 8.3 2.9 -2.2

1995 -4.4 -8.0 -0.4 2.1 10.3 17.8 19.4 18.0 11.3 9.2 -2.0 -7.4

1996 -8.3 -7.4 -2.0 4.3 10.3 16.4 17.9 18.9 14.1 6.1 -1.5 -2.0

1997 -8.5 -4.4 -4.4 3.4 8.4 16.4 19.1 18.3 13.5 7.4 -0.9 -4.6

1998 -5.1 -1.7 -0.2 6.6 15.1 15.4 18.4 18.6 14.1 7.0 1.3 -2.9

1999 -7.2 -3.4 -1.1 5.3 13.3 18.2 20.1 17.6 16.0 6.1 3.5 -3.1

2000 -8.5 -5.1 2.0 4.4 11.7 16.2 17.5 16.9 12.3 8.0 1.3 -7.5

Avg. -8.3 -6.8 -1.9 4.4 11.4 16.2 18.7 17.6 13.2 7.3 1.1 -5.6

SD 2.6 2.4 1.8 1.6 1.7 1.3 1.3 1.2 1.5 1.6 1.7 2.5
35

Table 19.—Average daily maximum, minimum and mean temperature (oC) by station and month, and number of years

used to calculate average for each station

Annual

Station Years Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec avg.

Daily Maximum

HQ 1957-1997 -2.5 -0.6 4.3 11.0 18.6 23.1 25.5 24.4 19.8 13.7 6.2 -0.4 11.9

1 1956-2000 -3.8 -1.9 2.7 9.2 17.1 21.5 23.8 22.5 18.0 12.1 4.7 -1.5 10.46 1961-1997 -5.3 -3.9 0.7 7.0 15.1 19.8 22.0 20.9 16.5 10.8 3.2 -2.7 8.7

14 1965-1997 -6.2 -4.3 0.9 7.4 15.4 20.3 22.5 21.2 16.3 9.5 2.3 -3.5 8.517 1999-2000 -6.7 -4.1 1.2 5.4 13.5 19.3 21.1 19.4 16.4 7.5 1.6 -5.6 7.423 1996-1997 -5.0 -2.3 1.3 7.0 15.1 20.4 22.1 21.4 17.1 9.2 1.7 -2.8 8.824 1999-2000 -5.9 -1.3 3.5 7.0 14.8 20.3 22.0 19.6 16.2 8.0 2.6 -4.4 8.5

Daily Minimum

HQ 1957-1997 -12.8 -11.6 -5.7 -0.2 5.5 10.4 13.1 12.2 7.9 2.4 -2.0 -9.2 0.8

1 1956-2000 -12.8 -11.7 -6.4 -0.4 5.7 10.9 13.5 12.6 8.3 2.5 -2.6 -9.6 0.86 1961-1997 -14.0 -12.9 -7.9 -1.8 4.8 10.1 12.6 11.7 7.5 2.0 -3.7 -10.6 -0.2

14 1965-1997 -14.2 -13.1 -8.1 -2.0 4.4 10.0 12.7 11.8 7.4 1.5 -4.0 -10.7 -0.317 1999-2000 -15.1 -11.6 -7.3 -3.0 3.4 8.9 10.9 10.5 7.7 0.2 -4.0 -12.2 -1.023 1996-1997 -13.4 -10.9 -7.9 -2.0 4.7 10.6 12.6 12.1 8.4 0.8 -4.2 -9.7 0.124 1999-2000 -15.3 -11.8 -7.1 -2.9 3.3 8.7 11.2 9.9 6.8 -0.9 -3.9 -11.7 -1.1

Daily Mean

HQ 1957-1997 -7.6 -6.1 -0.7 5.4 12.0 16.8 19.3 18.3 13.8 8.0 2.1 -4.8 6.4

1 1956-2000 -8.3 -6.8 -1.9 4.4 11.4 16.2 18.7 17.6 13.2 7.3 1.1 -5.6 5.66 1961-1997 -9.6 -8.4 -3.6 2.6 9.9 14.9 17.3 16.3 12.0 6.4 -0.3 -6.8 4.2

14 1965-1997 -10.2 -8.7 -3.6 2.7 9.9 15.2 17.6 16.5 11.8 5.5 -0.9 -7.1 4.117 1999-2000 -10.9 -7.8 -3.0 1.3 8.4 14.1 16.1 15.0 12.0 3.8 -1.2 -8.8 3.223 1996-1997 -10.2 -6.6 -3.3 2.5 9.9 15.6 17.4 16.7 12.7 5.0 -1.2 -6.2 4.424 1999-2000 -10.7 -6.5 -1.8 2.1 9.0 14.5 16.7 14.8 11.5 3.5 -0.7 -8.1 3.7
36

Table 20.—Average daily solar radiation (MJ/m2

) by month at HQ (1959-2000); estimated annual total calculated

by adding the 12 monthly averages and multiplying by 30.5

Annual

Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec total

1959 3.8 7.6 13.1 14.8 17.6 11.6 19.3 17.4 16.2 5.6 4.3 3.8 4118

1960 7.2 8.3 13.2 16.1 17.6 20.3 19.8 18.6 14.1 10.7 6.1 5.4 4803

1961 6.7 8.7 13.4 13.7 17.5 19.7 18.8 16.5 15.2 9.9 5.2 4.1 4550

1962 6.2 7.6 14.7 16.2 18.9 21.3 20.0 17.2 14.0 8.2 6.5 5.5 4761

1963 5.0 9.8 12.5 16.6 18.1 21.1 19.8 15.2 15.5 12.8 4.1 5.7 4766

1964 5.0 9.6 11.9 15.6 20.8 22.7 19.3 17.0 14.4 10.6 6.3 3.6 4779

1966 4.9 9.6 11.8 15.5 17.8 21.0 21.7 18.0 14.8 10.5 5.2 4.6 4739

1967 5.0 8.6 13.2 14.9 16.3 16.3 16.3 14.9 14.2 8.0 4.3 4.1 4151

1968 6.4 9.2 11.2 17.2 17.5 11.7 19.9 16.5 11.5 5.5 3.1 1.6 4004

1969 4.5 7.3 10.7 15.1 17.0 18.2 14.8 16.4 11.4 10.0 4.5 4.9 4111

1970 7.5 8.7 13.2 17.3 19.9 20.4 20.6 19.1 11.4 8.5 5.2 4.3 4761

1971 6.2 7.9 14.4 17.3 18.0 24.7 22.7 18.9 13.2 10.1 5.9 5.1 5015

1972 6.4 9.6 10.9 18.2 19.7 16.5 20.5 17.7 13.9 10.6 4.4 3.4 4628

1973 6.7 10.7 11.7 16.0 15.0 18.4 20.4 16.9 12.8 11.0 6.8 4.2 4596

1974 5.6 10.5 12.4 17.0 17.2 21.0 19.6 19.3 12.5 10.5 6.0 3.9 4739

1975 5.5 8.2 11.9 17.7 20.7 19.9 21.0 17.6 13.0 10.6 6.5 4.2 4783

1976 6.1 9.1 14.0 19.2 18.8 22.3 21.2 18.2 14.7 9.3 6.4 5.5 5026

1977 7.1 8.2 12.8 18.1 23.1 16.6 21.3 15.9 11.3 9.2 5.4 5.1 4701

1978 5.5 12.2 13.5 17.0 20.5 19.4 21.9 17.8 16.3 9.3 7.1 4.8 5039

1979 4.2 11.1 10.5 15.8 16.1 23.1 21.3 15.4 16.3 7.3 5.7 5.4 4648

1980 6.9 10.5 13.5 14.7 21.4 20.5 20.7 17.1 15.8 9.0 5.6 6.0 4932

1981 7.5 7.9 13.5 16.2 20.3 21.3 21.0 17.0 12.0 9.2 6.6 4.2 4784

1982 6.6 10.1 13.9 19.1 21.8 18.5 23.9 18.0 13.9 11.1 4.7 4.1 5059

1983 5.9 9.6 10.9 13.7 14.4 24.4 22.3 18.9 16.7 10.8 5.0 4.3 4787

1984 6.0 7.8 14.3 16.2 16.8 22.5 20.5 18.3 15.4 10.2 6.5 4.3 4846

1985 6.3 9.6 16.1 17.7 19.8 18.7 23.6 19.3 15.5 10.6 4.8 4.1 5070

1986 5.2 8.6 11.6 16.8 18.5 21.0 16.6 15.7 11.9 9.0 5.3 4.0 4394

1987 4.9 10.3 11.4 13.5 18.2 18.3 19.4 18.4 11.5 9.6 5.1 3.9 4411

1988 5.4 7.8 12.3 12.9 17.0 21.2 18.6 17.2 13.7 7.2 4.9 4.8 4362

1989 5.0 7.6 12.3 15.2 14.1 17.0 19.5 16.7 13.7 8.4 4.9 5.3 4263

1990 4.6 8.1 12.7 12.7 16.4 17.4 21.1 18.1 12.0 8.0 5.8 3.4 4279

1991 4.9 7.6 10.2 14.0 18.7 20.5 18.2 14.7 12.8 7.6 4.6 3.8 4205

1992 4.7 6.3 10.0 12.6 18.8 19.5 17.1 15.1 12.9 7.9 4.8 3.5 4063

1993 4.4 7.9 10.8 12.5 17.2 19.8 17.9 16.7 11.7 8.4 5.0 3.9 4150

1994 4.5 8.2 10.0 14.2 17.5 19.8 18.9 16.1 12.0 10.4 5.4 4.5 4314

1995 4.3 7.2 10.5 14.2 15.3 21.1 18.6 17.8 14.1 8.9 4.6 4.1 4288

1996 5.3 7.2 14.3 14.4 19.7 18.2 18.6 19.5 12.6 10.9 5.5 3.1 4558

1997 4.7 8.8 10.3 20.9 18.2 26.9 24.7 19.8 15.1 11.4 5.3 5.0 5219

1998 4.8 10.1 11.9 19.2 21.8 16.8 20.3 17.6 13.6 7.9 4.2 3.9 4640

1999 3.8 8.3 11.3 17.2 19.2 21.9 19.9 15.6 11.9 8.1 4.8 3.9 4454

2000 4.3 6.1 11.0 10.6 14.4 16.4 16.9 14.5 12.6 8.1 4.8 3.6 3765
Printed on Recycled Paper

Bailey, Amey Schenck; Hornbeck, James W.; Campbell, John L.; Eagar, Christopher.

2003. Hydrometeorological database for Hubbard Brook Experimental

Forest: 1955-2000. Gen. Tech. Rep. NE-305. Newtown Square, PA: U.S.

Department of Agriculture, Forest Service, Northeastern Research Station. 36 p.

The 3,160-ha Hubbard Brook Experimental Forest (HBEF) in New Hampshire has

been a prime area of research on forest and stream ecosystems since its

establishment by the USDA Forest Service in 1955. Streamflow and precipitation

have been measured continuously on the HBEF, and long-term datasets exist for air

and soil temperature, snow cover, soil frost, solar radiation, windspeed and direction,

and humidity. This information has provided the basis for hundreds of publications

by Forest Service and cooperating scientists on numerous aspects of forest

hydrology research as part of the ongoing Hubbard Brook Ecosystem Study. This

report updates the tables, methods, watershed descriptions, and other pertinent data

in “Thirty Years of Hydrometeorological Data at the Hubbard Brook Experimental

Forest, New Hampshire” (General Technical Report NE-141).

Keywords: Streamflow, precipitation, watershed studies, air temperature,

continuous measurements.
Headquarters of the Northeastern Research Station is in Newtown Square,

Pennsylvania. Field laboratories are maintained at:

Amherst, Massachusetts, in cooperation with the University of Massachusetts

Burlington, Vermont, in cooperation with the University of Vermont

Delaware, Ohio

Durham, New Hampshire, in cooperation with the University of New Hampshire

Hamden, Connecticut, in cooperation with Yale University

Morgantown, West Virginia, in cooperation with West Virginia University

Parsons, West Virginia

Princeton, West Virginia

Syracuse, New York, in cooperation with the State University of New York,

College of Environmental Sciences and Forestry at Syracuse University

Warren, Pennsylvania

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