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March,1995
農業環境技術研究所資料
第16号
1993年夏期の北極域ツンドラ(Ala§ka,Barrow)の微気象データ
原薗芳信・吉本真由美・宮田 明・内田洋平
George L.Vourlitis and Walter C.Oeche1
(環境資源部・気象管理科)
農林水産省
農業環境技術研究所 (平成7年3月)
農業環境技術研究所資料 第16号
審 査 会
会 長玉木佳男(所長)審査員原田二郎(企画調整部長)
11
〃
〃
〃
ノ1
ノ1
岡 田 齊 夫 (環境研究官)
齊藤利雄(総務部長)太 田 顕ズ環境管理部長)
蘭 道 生 (環境資源部長)
吉 野 嶺 一 (環境生物部長)
越野正義(資材動態部長)
農業環境技術研究所資料 第16号 平成7年3月10日印刷 平成7年3月15日発行
発行農業環境技術研究所 〒305茨城県つくば市観音台3-1-!発行者所長玉木佳男
電話0298-38-8186(情報資料課広報係)印刷佐藤印刷株式会社 〒310茨城県水戸市松ヶ丘2 323代表取締役佐藤隆男
薫灘鋸灘撫 、纏,羨、.,繊 麟鑑畿綴鰹1 謙難灘難
Photo.1 Bird’s-eye view of the coastal Arctic tundra close to thawing(near Barrow).
覧 偽 .誹乱
議灘灘灘鍵灘鐘灘を
触轟
盆
ξ ~ ξ 忌 …
猛藁轟、「麟瓢藁藤、許
Photo.2 0ver view of the coastal tundra near Point Barrow in mid-summer.
Photo.3 Landscape of tundra polygons contiguous to the measurement point of the IBP site
in mid-summer.
Photo.4 Setting up micrometeorological sensors and data lo99ers at the IBP site in mid-June.
Photo。5 The same as Photo.4except for the mid-July measurement.
炉ll
岳
壽
奮ギ
卸,
麟 l
Photo.6 The same as Photo.4except for the last August measurements.
監
轟鄭ザ~\
Photo.7 Snow covered tundra and setting up of measuring instruments near CMDL/NOAA
(June8,1993).
Photo.8 Measurements of fluxes of CO2,latent and sensible heat by the eddy correlation
measurement on snow covered tundra near DMCL/NOAA(June8,1993).
・葎黙 』雛ド 鴨z
馨璽騨贈鰭礪.
欝鞍善灘醗欝鷺、議轟螺、,、.、
Photo.9 View of snow cover after a fresh snow fall at Barrow in mid-August.
、、轡灘
Photo.10A close look at the coastal dry tundra at IBP site showing a random mixture of
fresh plants in a withered heath.
Photo. 11Meadows,small bodies of water feature and pond margin at the coastal wet
tundra at the Central Marsh site.
麟麟撫辮撫慧麟
懸叢蟻
鯨贋、灘
Photo、12CO2flux measurement at the IBP site using a chamber by the San Diego State
University group.
Misc.Publ.Nat1.Inst,
Agro-Environ.Sci.,16,/ 215(1995)
Micrometeorological Data and their Characteristics
over the Arctic Tundra at Barrow,Alaska
during the summer of1993
(Received June13,1994)
Yoshinobu Harazono,Mayumi Yoshimoto,Akira Miyata (National Institute of Agro-Environmental Sciences*)
Yohei Uchida
(University of Osaka Prefecture**)
George L.Vourlitis and Walter C.Oeche1
(San Diego State University***)
*Division of Agrometeorology,National Institute of Agro-Environmental Sciences,Kamondai,Tsukuba,305
Japan**Departmellt of Agriculture,Ullivers三ty of Osaka Prefecture,Sakai,Osaka,591Japan
***Department of Bioiogy,San Diego State Universlty,San L)iego,CA92182…0057,USA
Contents
1、Introduction・・9-
2.Location and methods
2.1Sites・………・…
2.21nstruments and setting them up for measurements……
1)Mlcrometeorologlcal components……一…・一…一………9………………・・…
2)Carbon dioxide concentrations
2.3Periods of data collection・・………需・
3.Acquisition of data and quality contro1
3.1Mode for processing input signals from sensors…………
3.2Quality control for data and.calibra.tions……
1)Temperature
2)Humidity…
3)Radiation and soil heat flux
4)Wind speed and direction
5)Aerodynamic parameters
6)Carbon diox量de concentration 一一・・・… 含一・…・一一99C・・一一・・‘・一・一6…・璽じD一一◎…
4.Additional reference data
4.l Background CO2concentration data by NOAA
42Monthly weather data from the National Weather Service
4.3Thaw depth
5.Notes on results
5。l Field conditions during measurement periods
5.2Daily variations of the heat budget components
1)Heat budget analysis
2)Typical result of heat budget over the tundra at the IBP site
5.31ntra-season variations of micrometeorological characteristics over the tundra・
6.Data tables ・・一一6一Ω・6・魯・・… 一6・噂・・U一一◎一一一・・一・… e9。修・・… _◎_6__.9.。._G_.。
7。Acknowledgments・………
8.References
Symbols
Data Iists of Central Marsh site
Data lists of IBP slte
1
3
3
4
・…6 7
8
9
9
9
9
・10
・11
・!工
・12
・14
・15
・15
・19
・ig
・21
・21
・22
・22
・24
・27
・3!
・33
・34
・37
・38
・76
Har&zonoαα」.l Micrometeorologlcal Data and Characteristics of Arctic Tundra in Alaska,1993 1
1.Introduction
The importance of atmospheric greenhouse gases on climatic warming has brought attention to
global sinks andsources ofcarbon in terrestrial ecosystems(Mooneyαα/.,19871Post,19901Schlesinger,
19901Tansα召/.,199010echel and Billings,!9921Harden6渉α1.,!99210echelαα1.,1993).Northem
ecosystems(tundra and boreal forests)comprise l3%of the earthツs land area but account for as much
carbon storage as22%of the terrestrial plant and soil organic matter,most of which(83%)is found in
seasonally thawed layers or trapped in permafrost(Miller,1981).
Northem ecosystems may be important for global carbon balance because dimatic warming
deepens the active layer of permafrost which causes erosion and eventual loss of permafrost over a great
portion of Arctic tundra and boreal forest(Oechel and Billings,1992).Consequently,Arctic hydrology
makes the upper soil layers dry and the decomposition rate of organic matter in soihncreases(Oechel
and Billings,1992).Furthermore,the rate at which carbon accumulates in terrestrial ecosystems
depends on the vegetation and climate,and on the presumed sensitivity of soil carbon accumulation or
loss to climatic change(Miller6砲1.,1983;Billings,1987).As a result,much of the carbon stored in the
active soil layer and permafrost is released into the atmosphere,thereby increasing and exacerbating
CO2caused warming(Billings6厩1.,1982)and changing the micrometeorology of the tundra.Elevated
atmospheric CO2,along with changed micrometeorology and changed mtrlent availability affect plant
c・mmmitiesandvegetati・n・lntheevent・fg1・bal.warminganditsatte卑dantec・systemandclimatic
changes,there is considerable uncertainty as to whether the northem ecosystem will act as a CO2sink
or not.
In the1970’s Coyne and Kelley(1971,1975)reported the characteristics of the micrometeorology
and CO2flux over an area of tundra at Barrow in Alaska,as part of a study of the US Intemational
Biosphere Program(IBP).Coyne and Kelley(1971)measured wind profiles at several heights,CO2
concentrations and air temperature profiles up to16meter in height,soil temperatures,solar radiation,
and some other factors at the IBP site area,and then revealed that the Arctic tundra was a sink of
atmospheric CO2.Recently,Oechel et al(1993)measured CO2flux at a coastal Arctic tundra durlng199!
and1992using a chamber method(see Photograph l2)and found that the Arctic tundra acts as a source
of CO2today.They compared their CO2flux data with those of the early1970’s determined by Coyne
and Kelley(1971,1975)in the IBP program.Although,the present micrometeorological characteristics
2 Misc.Publ.Nat1.Inst.Agro・Environ.Sci.,No.16(1995)
at the site were not investigated precisely,the comparison of the micrometeorological data obtained at
two dlfferent times with a twenty year difference can improve the understanding of the characteristics
of Arctic tundra and the climatic warming.
This study was carried out to examine whether the coastal Arctic tundra acts as a sink or source
today,with comprehensive measurements during the summer in1993.The observation site was the same
ピoastal Arctic tundra at Barrow,Alaska,used in the1970’s by Coyne and Kelley(1971,1975).A
micrometeorological survey and flux measurements were made using aerodynamic,heat budget,and
eddy correlation methods.The micrometeorological data were obtained over almost all of the summer
season of1993at Barrow.These results are valuable not only for further study of the Arctic ecosystem
but also for assessing the contribution of tundra vegetation to global warming.Therefore,the data is
reported here along with the analysis on the changes of CO2flux over the20years and the differences
in CO2flux between wet tundra and polygonal dry tmdra in the Arctic tmdra ecosystem will be done
in the near future.
Harazono6齢♂。:Micrometeorological Data and Characteristics of Arctic Tundra in Alaska,1993 3
2.Location and methods
2.1Sites
The observation sites are located at tv~70sites over coastal Arctic tundra near Barrow(71。18’N,
156。47〆W,with a populationofapproximately4000),thenorthemmostcityinAlaskafacingtheChukchi
Sea.The Arctic coastal tundra is characterized by low relief,and dominated by ice-wedge polygons,
shallow,oriented lakes and drained basins(Bunnellαα1.,1975).Over views of the Arctic tundra are
shown’in Photograph l during the thawing period of spring and Photograph2in mid-summer.The
former measurement site is named the IBP site,and the latter the Central Marsh site.The locations of
the two sites are shown in Fig.1.
Barrow
、
、 . じ 3 》㍗ ● 先,。
ゆ ノ ジのヤヘじメ
ALASKA
ARCTIC OCEAN
CHUKCHl SEA
℃
EAUFORτSEA
N
十~
∂
Browervi“e
Barr讐撫
○ 80
」
も
0 も
o
Marsh site
2 4
ELSONLAGOON
o
もρo o o
》 ノ
6km
Φ iBP site
八○\。
Fig.1 Map of contiguous Alaska(inlet)and details of an area adjoining to the
measurement sites(the IBP and the Central Marsh sites).
4 Misc.PubL NatL Inst.Agro-Environ.Sci.,No.16(1995)
The IBP site is located2.5km east of the edge of Browerville village near Barrow city and2.5
km from the southeast coast of the Chukchi Sea.This site is the same experimental site as that of the
USIntemational BiosphereProgram(IBP)Tundra Biomeintensivesite(71Ql7〆68”N,156041〆33”W)ofthe
l970’s.The measurement point was set at about300m south of the edge at a small creek that rms from
Footprint Lake which is located south of the site.Flat tmdra stretches over several kilometers in all
directions from the measurement point except for the small creek,and an uneven polygonal pattem
(polygon)20to40cm in heig且t is scattered over some parts of the ground surface around the measure-
ment point.The polygon around the IBP site is shown in Photograph3.Sufficient fetch length was
obtainedofmorethanlkminthedirectionbetweenthenortheastandnorthwestand300mtothenorth,
which was sufficient to evaluate the fluxes of momentum,heat and gases using micrometeorological
techniques.There was an unpaved road about O.8km east of the measurement point but with very little
traffic,and there was no serious influence of human activities to disturb the measurement except for
CO2discharged from a gasoline power generator.
The Central Marsh site(hereinafter Marsh site)is located7km northeast of Barrow,2km
southeast of the Chukchi Sea shore,and2km west of Elson Lagoon.The Central Marsh is a dried
Iagoon with an elliptic shape of approximately3km in major axis and1.5km in minor axis,and is now
a flat and wet lowland.A wide bank rim(ridge)about2m in maximum height and100m in width
surromds the marsh.The measurement point(71019〆27”N,156Q37〆09”W)was about300m from the
nearest northeastbank-edge.The fetch ofthe Marsh site was more than l km to mostdirectionsexcept
the northeast bank,and the influence of human activities on the measurement was as little as that at the
IBP site.
2.21nstruments and Setting them up for measurements
Field measurements were carried out at both sites using towers.A typical schematic view of
measurement at the IBP site is mustrated in Fig.2,and the setting conditions at the IBP site are shown
in Photographs4,5,and6in mld-June,mid-July and late-August.At the IBP site,most measurements
were carried out from June l5to July18and from August9to August25,and some elements were
measured between July19and August8.While at the Marsh site,almost the same elements as at the
IBP$ite were measured between July20and August8.The measured elements,instmments and their
Harazonoαα」.:Micrometeorological Data and Characteristics of Arctic Tundra in Alaska,1993 5
mounting conditions at each site are listed in Table l for each period。
TheEB750powergenerator(AC120V,60Hz,750W=Honda,Tokyo,Japan)wasusedtosupply
power for measurement at the IBP site.The generator was placed more than lOO m north of the tower
by June21,and was then moved to more than200m north to avoid CO2contamination from the
generator.Whlle at the Marsh site,we used the commercial power supply from the field observatory
oftheNationa1GeographyService,whichwasabout400mfromthemeasurementtower.
vegetationthawdeptht
RFACE LAYER
UV
AcllVE ■
LAYER
PERMAFROST
_皇丁Ωanemometer
軋 wind vane【{Lpsychr・meter
合
ワ
→凸
UV
凸
pyranometer(downward)
pyranometer(upward〉
net radiometer
B-range u ltra-
violet radiometer
photon flux meter(PAR)
一一z==7’heat刊ux p!ate
thermometer
一『一(soil temperature〉
5gasinlet
Fig.2 Schematic illustration of the setting up of instruments at tundra.
6 Misc.Publ.Natl.Inst.Agro-Environ.Sci.,No.16(1995)
Table l Measured elements and their set.up heights at the field.
Element Symbol Helght(m) Sensor
Wind speed(highest〉
Wind speed
Wind speed(middle)
Wind speed
Wind speed(lowest)
Wind direction
ul
U2U3U4∪5
粉
4.7
2.0
1.2
0.7
0.3
4.7
Cup anemometer
Cup anemometer
Cup anemometer
Cup anemometer
Cup anemometer
Wind Vane
CO2Concentration(higher) CO2-H
CO2Concentration(10wer) CO2-L2
0.3
NDIRCO2analyzerNDIR CO2analyzer
Inlet height
lnlet height
Solar Radiation
Reflection of Rs
Net Radiation
PhOtOSynthetiC ACtive
Radiation
Ultra Videt lntenSity
困
舳㎞
PAR
UVb
1.0
0.9
1.2
0.3
0。3
Thermop“e Pyranometer
Thermop“e Pyranometer
Net Radiometer
Photon sensor
UV radiometer
Dry bulb Temperature(highe
Dry bωb Temperature(middl
Dry bulb Temperature(lower
Wet bulb Temperature(high∈
Wet bulb Temperature(midd
Wet bulb Temperature(iowel
Soil Temperature
So“Temperature
Soil Temperature
Soil Temperature
Tal
Ta2Ta3TwlTw2Tw3Tsl
Ts2Ts3Ts4
2
1.2
0.3
2
1.2
0.3
0.01
0.05
0.10
0.20
Ventilated psychrometer(PT-100)
Ventilated psychrometer(PT-100)
Ventilated psychrometer(PT-100〉
Ventilated psychrometer(PT-100)
Ventilated psychrometer(PT-100)
Ventilated psychrometer(PT-100)
Thermocouple(Type-T)
Thermocouple(Type-T)
Thermocouple(Type-T〉
Thermocouple(Type-T)
Soil Heat flux
So縫Heat flux
Gl
G20.005
0。005
Heat flow plate
Heat fbw plate
1)Micrometeorological components
The vertical wind profile was measured using5cup-anemometers(014A,Campbell Scientific Inc.,
Logan,USA)which were mounted at up to4.7m in height with a horizontal boom extending O.5m from
the tower.Wind direction was measured with a wind vane(024A,Campbell Scientific Inc.,Logan,USA)
at the same height as the top anemometer.Dry-bulb and wet-bulb temperatures were measured using
ventilated psychrometers(hand-made and calibrated with Asmanゴs psychrometer)with a platinum
resistance thermometer at three different heights.The other two sets of psychrometers consisting of a
T-type thermocouple sensor(Copper and Constantan,0.31mm diameter)were mounted at two different
Harazono6厩/.:Micrometeorological Data and Characteristics of Arctic Tundra in Alaska,1993 7
heights on the other site.Soil temperatures at two to four depths were measured with the T-type
thermocouple.Measured depths were1,5,10,20cm below the surface,but the depth varied with the
observation sites because of the limitation of the terminal numbers of the data logger.Depth is shown
in the data tables for each measured site.Soil heat flux was measured with two thermopile-type heat
flux plates(MF-9,Eko Instruments Co.,LTD,Tokyo Japan),and both sensors were buried at O.5cm in
depth and the average value of the two was obtained.
Downward solar radiation(Rsd)and reflected solar radiation(Rsu)were measured with ther,
mopile-type pyranometers(MS-62,Eko Instruments Co.,LTD.,Tokyo,Japan),and each was mounted
horizontally but facing opposite directions,and this set was used at the IBP site.The other thermopile
-type pyranometers(PCM-03,Kipp&Zonen,the Netherlands)were used only at the Marsh site.Net
radiation was measured continuously at the IBP site using a thermopile-type ventilated net radiometer
(MF-!1,Eko Instruments Co.,LTD.,Tokyo Japan),while a non-ventilated sensor(Q-6,Campbell
Scientific,Inc.,Logan,USA)was partly used at the Marsh site.Photosynthetic active radiation(PAR)
was measured with a silicon photo diode-type photon flux meter(ML-020P,400-700nm in wavelength,
Eko Instruments Co.,Ltd.,Tokyo,Japan). B-range ultraviolet radiation(UV-B,280-315nm in
wavelength)was also measured with a silicon photo diode-type UV-B meter(MS-210W,Eko Instru-
ments Co.,LTD.,Tokyo,Japan)during the latter half of the measurement period.
2)Carbon dioxide concentrations
The carbon dioxide(CO2)concentration was measured using a non-dispersive infrared gas
analyzer(ZFU1,Fuji Electric Co。Ltd.,Tokyo Japan).Air at the two tower heights were sampled
through each Teflon tube with a polyfluon filter(PFO50,Toyo Filter,Ltd.,Tokyo,Japan)at flow rates
of LO dm3/min.Sampled air at each height was sent continuously to the switching solenoid valve(NCV
-3,Takasago electric Inc.,Tokyo,Japan),and one of them was altemately sent to the cell of the CO2
analyzer。Watervaporincludedinthesamplewasremovedusingasemi-permeabledrier(ZBJO250,Fuli
Electric Co.Ltd.,Tokyo,Japan)before the inlet of the celL The solenoid valve was controlled every
70seconds interlocking with data acquisition by a data logger(21X,Campbell ScientificJnc。,Logan,
USA).This system was used at both the IBP and Marsh sites.
Another non-dispersive infrared gas analyzer(ZFP9,Fuji Electric Co.LTD.,Tokyo,Japa血)was
8 Misc.PubL NatL Inst.Agro-Environ.Sci.,No.16(!995)
also used at the IBP site from July19to August8、In this system,the air flow rate was O.6dm3/min,
andthesolenoidvalvewasswitchedevery60seconds.Watervaporwit且inthesampledairwasremoved
by the membrane filter installed in the analyzer.However,the control of the switching valve by the dat3
10gger(CR10,Campbell Scientific,Inc.,Logan,USA)failed for most of the measurement period due to
the wet and cold conditions at the IBP site.
Calibration of both analyzers was made at any interval during the measurement periods using two
levels of CO2standard gases(299.4ppm and473.6ppm).
2.3Periods of data collection
The preliminary measurement was carried out over snow-covered tmd.ra near the Climatic
Monitoring and Diagnostic Laboratory(CMDL),Nationa10cean&Atmospheric Administration
(NOAA)located at the east of Central Marsh in Barrow from June8to!0.The circumstances of the
measurement over snow covered tundra are shown in Photographs7and8. These preliminary
measurement data are not listed in this data book.
Measurement at the IBP site was carried out from June15to August25,and at the Marsh site
from July19to August9.Most data were obtained at the IBP site,because there was not enough
equipment for both sites.During the measurement period at the Marsh site,some sensors were moved
from the IBP site to the Marsh site,therefore wind speed and wlnd direction were not measured and the
number of measurements of depth of soil temperature and ventilated psychrometer were fewer than in
other periods.
In the summer season,the summer time system is used in Alaska and the Alaska Standard Time
(AKST)was8hours later than Greenwich Mean Time(GMT).In this paper the time is specified in
AKST to show the data w1th time.
Harazono6砲」.:Micrometeorological Data and Characterlstics of Arctic Tundra in Alaska,1993 9
3Acquisition of data and quality control
3.l Mode of processing input signals from sensors
A digital data logger21X(CampbeH Scientific Inc.,Logan,USA)with a relay multiplexer
(AM416)was mainlyused to collectbothmeteorological andCO2concentration data atboth observation
sites.Micrometeorological data were sampled every70seconds and the10minute average was
recorded,because the AM4160f the platinum resistance thermometers did not work atthesame interval
as the撃interval timer SDM-INT80f the cup anemometers in the field.Another digital data logger CR10
(Campbell Scientific,Inc.,Logan,USA)was used at the IBP site on Ju玉y l9and August8.In出is data
acquis量tion system,data were collected every lO seconds and averaged every lO minutes and then
memorized.Data were subsequently processed in the laboratory after each run.
3.2 Quality control of data and.calibration
Data stored in the data logger were checked for errors,and then the numerical values were
converted to physical values with dimension.Correction of data was carried out for10mimtes
averages,then averaged again for every30minutes,the30minute average being specified as both
periods from10to40minutes(specified as OO of each hour in the tables)and from40to10minutes
(specified as300f each hour in the tables).
1)Temperature data
There was no correction for soH temperature data obtained using thermocouples,because there
was no significant difference among the sensors and the reference temperature of the logger was thought
to be almost constant in the shielded wooden box.Platinum resistance thermometers were used as the
sensors of the ventilated psychrometers which were calibrated at the National Institute of Agro
-Environmental Sciences(NIAES)before and after the field measurement,and differences among the
sensors were checked by setting them at the same conditions(location,height,direction)in the field.
The field comparisons of the sensors were made three times from June8to August25.The calibration
factor for each sensor and the modified factor obtained by field checks were used in the calculation.
Though,the thermoco⑮1e was also used as the sensors of ventilated psychrometers,the calibration and
correction of these psychrometers were made in the same way as those with platimm resistance
thermometers.
10 Misc.Pub1.NatL Inst.Agro-Environ.Sci.,No.i6(1995)
In the data tables,Ta1,Ta2and Ta3represent the30minute average air temperatures(℃)
obtained by the ventilated psychrometers at each leve1.Tsl,Ts2,Ts3,and Ts4represent the30mimte
average soil temperatures(℃)obtained by the thermocouples。
2)Humidity
Saturation water vapor pressures(mb)were calculated using the Goff-Gratch formulation(List,
1971)for wet bulb temperatures at each measured height.The formations used in the calculation for
liquid water and ice were as follows:
乃
1096w,二一7。90298( 一1)十5.02808109 T
アマど10-3(10-3・49149(了一一1)一1)十lo9(!013.246)
To
lo96i,コー9.09718( 一1)一3.56654109 T
% 一1.3816T
ア10 7(101L344(1一万L1)+8。1328
To +0.876793(1一一丁
T )十lo9(6。10714)⑰
(1〉
(2)
where,
6wS=saturation vapor pressure of pure ordinary liquid water(mb)
6isπsaturation vapor pressure of pure ordinary water ice(mb)
T=absolute temperature(K)
ルニsteam point temperature(373.16K)
To=ice point temperature(273.16K)
Vapor pressures6w(mmHg),relative humidityノ~H(%),absolute humidity of the air/1∫ノ(g/m3)were
calculated using the following formulations.
6w二〇.750617(6w、一〇.000660(1+0。00115!ωソつ(孟ゲ!ω)) (3)
6w
ノ~Hニ100 (4) 6wsd
6w
・4HニLO6 (5) (1+0.00367孟d)
where,
8w,d=saturation vapor pressure for dry bulb temperature(mmHg)
Harazono6齢1.:Micrometeorological Data and Characteristics of Arctic Tundra in Alaska,1993 11
ち二dry bulb temperature(℃)
砺=wet bulb temperature(℃)
P=atmospheric pressure(mmHg)
We did not measure the air pressqre P,therefore,the standard value of760mmHg was used in
the calculation of equation(3).In the data tables,AHl,AH2and AH3represent the30minute average
absolute humidity(g/m3)in the air at each level calculated as mentioned above.RH1,RH2,and RH3
represent the30minute average relative humidity of the air obtained by formulation(4).
3)Radiation and soil heat flux
Data on net radiation,downward solar radiation and its reflection from the surface,were
corrected using each calibration factor.Data on soil heat flux obtained using two heat flow plates were
corrected in the same way as was radiation,then the averaged value of the two was determined as the
soil heat flux(G,W/m2)listed in the data tables.There was no correction owing to the heat storage
between the surface and the heat flow plates because the thickness of the soil over the heat plate was
very thin.
In the data tables,Rsd and Rsu represent the30mimte average downward and upward(reflected)
solar radiation(W/m2),respectively。Rn represents the30minute average net radiation,UVb represents
the30minuteaveragefluxdensityofthe B-rangeultravioletradiation(W/m2),and PARrepresentsthe
30minute average photon flux density of photosynthetic active radiation(μE/sm2〉at the field obtained
by each sensor mentioned in section2.2.
Albedo was calculated using downward solar radiation Rsd and its reflection Rsu.Because the
incidence angle of the sunラs beams is low over the Arctic tundra,the accuracy of the pyranometers
lessened with the increase of the incident angle.Thus,the reflection of solar radiation Rsu was greater
than the downward solar radiation Rsd in some cases,therefore calculated albedo values over O.5were
omitted from the data tables.
4〉Wind speed and direction
Five cup anemometers were used in the field.The differences among the anemometers were
checkedinthewindtunnelofNIAES(thetests“ctionwas2,2,9minwidth,height,length,respectively
and the wind speed range was O.3-25m/s)and in the field in the same way as the psychrometers.At
first,a data sampling interval was designed every10seconds for the5anemometers simultaneously with
12 Misc.PubL Natl,Inst.Agro.Environ.Sci.,No.16(1995)
the interval timer SDM4NT8,but SDM-INT8did not work with AM416in the field.Therefore,wind
speed was measured by counting the pulse of each anemometer every10seconds altemately,thus
determining the wind profile every70seconds.Data were corrected using modified calibration factors
obtained in the field。Field calibrations of all sensors were carried out three times at the same height
over the tundra during the observation period.
In the data tables,UI to U5represents the30minute average wind speed(m/s)at each level.
Owing to the different sampling timings of wind speed(every70seconds)the inversion of the wind
profile was sometimes observed,therefore only three levels of wind speed are listed in the data tables.
WD represents the30mimte average value of wind direction,a number was specified from O to360
degrees for the clockwise rotation from north-east-south-west-north.
5)Aerodynamic parameters
In order to investigate micrometeorological conditions,aerodynamic parameters were evaluated.
The following is an outline of the methods used.
In the boundary layer,the wind profile over the vegetation or the ground surface can be expressed
as formula(6)under neutral atmospheric conditions.
%。 (㍗ゴ)%(z)= 1n
κ Zo
(6)
where麗(z)is the average wind speed at any height~,麗。is the friction velocity,κis the von Karmanヲ
s constant(0.41),ゴand2。are zero plane displacement and the roughness length of the surface.In the
turbulent boundary layer over vegetation,momentum fluxτwas given by equation(7).
4κ
τ=一ρK窺 コρ銘*2二一ρ鋸躍 ゴz
(7)
Whereρis the density of air,魚n,the eddy diffusivity of momentum.According to the mixing-1ength
hypothesis by Prandt1,観is obtained as equation(8).Where lm is a mean mixing length and is
proportional toκand z in the turbulent boundary layer(Arya,1988).
Harazono6地」』Micrometeorological Data and Characteristics of Arctic Tundra ln Alaska,1993 13
鋸側二一1吻2 磁4%ぬ 4z
(8〉
Thus,κ郷is also expressed using wind profiles as equation(9),and an integrated formula to calculate
the momentum flux is given as follows(Denmead,1970).
K窺=κ2z2
τ 2}二κρ
4% π z△π ニだ コだ 4z ln(z/9。) 1n(z2/2、)
△κ△κ =穿△%{1n(z2/z,)/2
(9)
(10)
where△祝is the difference in the wind speed between the heights of z、and z2,andρブis diffusive
(diffusion)velocity for the momentum between the two heights.Then,diffusion velocityρブcan be
obtained from the next formula under neutral atmospheric conditions二
穿rln(z、㌔~望孟望,一ゴ)),(11〉
廊,and偽are mean wind speeds at height z、and22,respectively and4and other aerodynamic
parameters such as z。and%。can be obtained by the regression line of the logarithmic wind profile
(Harazonoαα1.,1990,!993),using the following equations,where a and b are coefficients of the
regreSSiOn eqUatiOn、
ln(z-4)二azゼ(z)十b (12)
籏二κ/a (13)
z。=exp(b) (14〉
If the atmospheric stability is negative,穿has to be corrected according to the stability function
(Thom,1975).In this study,the Richardson number甜was used to check atmospheric stability,and the
flux was modified using a corrected function with specific function F(Ri).
14 Misc.Pub1.Natl。Inst.Agro-Environ.Sci.,No.16(1995)
κ2(麗1一%2〉
穿c二 F(R♂) (1n(ZI-4)一1n(z2-4))2(15)
The corrected diffusion velocityρたwas obtained from formula(15)according to Thom(1975),and the
specific function F(1~Z)of the Richardson Number1~i is given in formula(16).7i1.7む2,T are the air
temperatures at heights zl and z2,and mean temperature(unit K),respectively.
9 (7も1-7』2)(Zr22)ノ百二
丁(麗1一κ2)2
F(Ri)=(1-161~歪)o・75
F(ノ~乞)二(1-5Rガ)2
一〇.2<1~乞<0
0<ノ~i<0.2
(16)
(17-a〉
(17rb)
In the data tables,~。(cm),u。(m/s),Rねnd航(cm/s)are listed,havingbeen calculated according
to the above analysis.穿in the data table is a modified value for gas transportation(the same asρた),
and it will be useful to evaluate CO2flux,water vapor(1atent heat)flux,and sensible heat flux in the
following analyses.Although,there is some uncertainty in the correction equations(17-a,b),the穿
value may be modified slightly in further studies.
6)Carbon dioxide concentration
Calibration of the infrared CO2gas analyzer was carried out using two standard gases in the field
and laboratory in Barrow.The levels of the standard gases used were299.4ppm and473.6ppm.
Unfortunately,at the IBP site,we had to stop the generator almost once a week in ord.er to change the
oiL Output levels of the CO2analyzer shifted slightly after restarting the generator,therefore some CO2
data obtained after the maintenance of the generator were modified。
Backgromd CO2data were providedby NOAA’s Climatic Monitoring andDiagnostic Laboratory
(CMDL)located to the east of Central Marsh in Barrow.Because there are great differences in
averaging,sampling heights,sampling equipment and sampling intervals between the background data
by NOAA and the measured data over the tundra,there might be some differences in the concentration
levels listed.
Harazonoαα1.:Micrometeorological Data and Characteristics of Arctic Tundra in Alaska,1993 15
4.Additional reference data
4.1Background CO2concentration data by NOAA
Hourly backgromd CO2data from the micrometeorological measurement period are also listed
in the data tables(B-CO2).These data were prepared by NOAA’s Climatic Monitoring and Diagnostic
Laboratory(CMDL).The air at15m high tower was sampled and analyzed by an NDIR analyzer
(ULTRAMAT,Siemens,Germany).The averaging periods inhours are specified asthebeginning ofthe
hour,for example,hour5corresponds to5AM to6AM AKST.Therefore,the averaged periods of
background CO2concentrations are different from those of measurements of the CO2concentrations
overthetundra.Aselectionprocesshasundertakentodistinguish“background”concentrations,that
is,thevaluesthat CMDLbelieved were not contaminatedby local sources or sinks ofCO2were selected.
The selection process depended on the station(Petersonαα1.,1986).The collected air sample,which
was from a strict clean air sector,was as a defined wind direction between20an(i1!0degrees for
Barrow.The standard deviation of the1-minute average had to be less than O.3ppm,otherwise the hour
gets a“V”(variable)flag.Also,the average change from one hour to the next is less than O.25ppm.
Some data have additional codes,and there are a large number of possible codes,but the most common
codes used in the tables are:
C-Weekly calibration of reference gases,no data available
I-Instrument malfunction,no data available
V-LargevariabilityofCO2concentrationwithinonehour
D-Hour-to-hour difference in concentration>0.25ppm
A-Automatic selection based on residuals from a spline curve
Details conceming the background data by CMDL/NOAA were reported by Peterson6砲1.(1986).
16 Misc.Pub1.Natl.Inst.Agro-Environ.Sci.,No.16(1995)
Table2Monthly climate data of Barrow National Weather Station on June,1993.
Date Precipitation T max.
(mm) (OC)
T min.T mean(OC) (OC)
Wind max.Wind mean (m/s) (m/s)
123456789101112131415161718192021222324252627282930
0.3
2.8
0.3
5.8
0.3
0.3
1.3
0.3
0.6
1.7
1.1
1.7
0.0
0.0
2.2
6.1
5.0
2.8
3.9
1.7
7.8
3.3
10.68.3
1.7
6.7
5.0
3.3
3.3
3.3
2.2
2.8
3.9
6.7
11.717.817.211.7
一1.7
-1.7
-2.2
-2.2
-3.9
-3.9
-1.7
0.6
0.6
0.6
0.0
-0.6
0.0
-0.6
-0.6
-0.6
-1.7
-1.1
0.0
0。0
0.0
-0.6
0.6
0.0
-0.6
-0.6
2.2
3.3
8.9
1.1
一〇.6
0.0
-0.6
-0.3
4.9-1.9
0.3
3.3
2.8
1.7
1.9
0.6
3.9
1.4
5.0
3.9
0.0
2.8
2.5
1.7
1。7
1.4
1.4
1.4
1.7
3.1
6.9
10.613.1
6.4
5.8
5.4
5。4
6.7
9.8
12.512.56.3
6.7
6.3
9.8
12.510.7
8.9
7.6
7.6
4.0
5.8
5.4
6.7
7.2
6.3
6.7
6.7
8.9
9.4
5.8
7.2
5.8
7.2
4.003.474.075.017,469.5:2
7.784.605.453.986.489.705.056.71
4.205.003.583.583.264.255.774.115.194.966.357.423.174.162.644.60
HaraZ。n。6!α1.:癩icr。mete。r。1。gica1DataandCharacteristics・fArcticTundrainAlaska,1993
Table3Monthly climate data of Barrow National Weather Station on July,1993.
17
Date Precipitation T max.
(mm) (OC)
Tmin.(OC)
T me&n Wind max.
(o“) (mls)
Wind me&n (m/s)
1234’
5678910111213141516171819202122232425262728293031
1.5
0.3
0.8
0.3
4.1
0.5
0,3
0.8
0.3
4.6
3.8
7.8
6.1
5.6
10,03.9
3.9
6.7
11,717.814.412.822.226.122.813.311.1 8.3
13.98.4
20.04.4
5.6
13.39.4
6.7
20。012.8
9。4
10.65.6
9.4
1.1
1.1
1.1
2.2
1.7
1.7
1.1
2.2
6.7
6。7
6.1
6.7
8.9
7.2
5.0
4.4
3.3
5.0
5.0
2.8
1.7
1.1
2.2
0.0
0.0
2.8
7.2
2.2
1.1
-0.6
0.0
4.4
3.6
3.3
6.1
2.8
2.8
3.9
6.9
12.210.6
9.4
14.417.515.0
9.2
7.8
5.8
9.4
6.9
11.43.1
3.3
7.8
4.7
3.3
11.410.0
5.8
5.8
2.5
4.7
10.713.4
9.4
6.3
6.3
5.4
5.8
5.8
9.8
8.0
10.78,0
10.710.3
8.9
7.2
8.9
7.6
4.0
8。0
8.0
7.2
6.7
7.6
8.9
8.9
7.2
9.4
19.213.0
7.6
8.0011.30
7.003.71
4.294.254.203.985.866.087.924.346.265.865.864.745.775.102.774.206.795.104.924.435.455.874.344.34
12.50
5.954.65
18 Misc.PubL Natl.Inst.Agro-Environ.Sci,,No.16(1995)
Table4Monthly climate data of Barrow National Weather Station on August,1993.
Date Precipitation T max。
(mm) (OC)
Tmin.(OC)
T mean Wind max.Wind mean(OC) (m/s) (m/s)
12345678910111213141516171819202122232425262728293031
4.8
4.6
0.3
0.8
0.8
0.3
1.5
1.8
4.6
2.8
1.0
1.8
7.8
7.8
3.9
2.8
2.2
2.8
1.7
2.2
3。3
8.9
6.7
2.2
3.3
2.8
1.1
2.8
8.9
13.312.8
9.4
7。2
2.8
2.2
4.4
6.1
4.4
5.6
4.4
2.8
1.1
0.0
2.8
0.6
-0.6
-1.7
-0.6
-1.7
-0.6
-2.2
0.6
1.1
-0.6
-0.6
-0.6
0.0
0.0
-0.6
1.7
2.2
3.3
2.8
1.1
0.6
1.1
2.2
2.8
2.2
2.2
1.7
0.0
-1.1
-1.7
5.3
4.2
1.7
0.6
0.8
0.6
0.6
0.0
、1.9
5.0
3.1
0.8
1.4
1.4
0‘6
1.1
5.3
7.8
8.1
6.1
4.2
1.7
1.7
3.3
4.4
3.3
3.9
3.1
1.4
0.0
-0.8
8.9
6.7
5.4
8.0
9.4
7.6
8.9
6.3
8.0
10.38.9
11.28.9
6.3
5.8
7.6
7.6
8.0
10.710.7
6.7
5.8
4.5
4.0
6.7
4.5
4.0
9.4
9.4
6.3
6.7
4.164.112.596.267.116.085.414.745.996.446.978.586.794.164.605.055.995.457.336.883.984.693.132.864.113.352.996.487.064.964。20
Harazono6厩1.:Micrometeorological Data and Characteristics of Arctic Tundra in Alaska,1993 19
4.2Monthly weather data from the National Weather Service
There is a first order National Weather Service(NWS)station located in the center of Barrow.
Climate data listed in this data book were collected and compiled by Brown6緬1.(1994).Monthly data
fromJune,July and August are shown in.Tables2,3,and4.Maximum andminimumtemperatureswere
recorded automatically,and mean temperature was calculated from a max-min amplitude.Precipita-
tion was recorded at70’clock(AKST)on the next day,and the record period was different from
temperature data.Windspeedwasmeasured atthetop ofthe stationbuildingwhichwasmorethan10
m inheight,therefore the wind speed listed inthe Tables2to40btained at NWS/Barrowwerehigher
thanthoseobtainedat4.7mhighoverthetundra.
The station is located in the center of the city and there are rhany buildings near the station.
Temperatures in the city might have been higher than that over tundra because of the effects of urban
climate in the data of NWS,especially in summer.
4.3Thaw depth
Thaw depth was measured by striking an iron stick(diameter8mm)vertically into the ground
to the permafrost table.Measurements were made almost every week for the IBP and Central Marsh
sites.At the IBP site,we measured thaw depth at four different conditions on the ground,high center,
low center,the rim(ridge)of the polygon and ice wedge(trough).The schematic illustration of the
polygon ls shown in Fig.3(after Patrick,1978),At the Marsh site,measurements were carried out at
both the upland(dry tundra)of the bank side and the lowland(wet tundra)of the basin.At each point,
more than10samples of thaw depth were measured and the average was used for analysis.The trend
of thaw depth is shown in Fig.4for the IBP site,in Fig.5for the Marsh site.
20 Misc.Pub1.Natl.Inst.Agro.Environ.Sci.,No.16(1995)
HC:High CenterLC:Low Center
R :Rlm(R重dge)
IW:lce Wedge(Trough)
ロ ロ
l IW:塵 卿
廊 置
輩 魎
8 ■
■ 9
一 一
■ ,
9
HC5()礎二恩…”””一”
び ロ
iIW i R i 騨, 暉 ■ヨ リ 艦ヨ ヨロ ヨ ロ= l x・・ ’ LC
i R iiW io ■ 唇
ヨー ■塵 ・ ・9 8 1
ロ■ 璽響 9., 3 一 , ・
5
30m
Fig.3 The principal micro relief features of polygons at the IBP site(after Patric,1978)。
Harazono6短1.:Micrometeorological Data and Characteristics of Arctic Tundra in Alaska,1993 21
5.Notes on results
5.1Field conditions during the measurement periods
The sm was abqve the horizon from the begiming of measurement till mid-August。More than
80%of the snow melted by June10at th今Marsh site and by June12at the IBP site・However,snowfall
was observed even in the moming in July and in the daytime in mid-August,and we had3cm of snow
on August15(Photograph9).Fog was often observed at both sites,especially in June and August.The
beach of the Chukchi Sea was covered with ice floe ti111ate June.After early July,ice floes left the
beach,but sometimes came close to the beach with strong northerly winds.
According to a report of the first order National Weather Service(NWS)station located in the
city of Barrow,July1993was the second warmest July on record,but August was cooler than usua1
(Brownαα1.,1994).
Vegetation at IBP site was a relatively dry coastal tund.ra community consisting of several
species of dry heath,wet heath,and mist meadow(Bumel1αα1。,1975).At the beginning of the
measurement(mid-June),there was no living grass but dead shoots whose average height was less than
10cm(Photograph4).Although,the density of the grass was low,the soil was covered with a moss
carpet whose depth increased with thaw depth and with a maximum thickness of about10cm.Fresh
leaves of grass germinated over the moss surface after late Jme,then grew up to about25cm in late
July(Photograph10).Thaw depth was different at the high c6nter,10w center,rim and ice wedge of the
polygon.The former was deeper than the latter,and the maximum depth was28cm at the high center
in early August,while that at the ice wedge it was21cm.The trend in thaw depth is shown in Fig.4。
The vegetation at the Marsh site was a wet meadow tundra community,and the major plants
around the observation site were some species of wet meadow and pond margin(Bmnel1α召1.,1975).
Some species of meadow germinated in the pond in late June and grew to about15cm in average height
in late July,and to a maximum height of25cm in early August(see Photograph11).Surface conditions
at the measurement point were shallow puddles(pond),much wetter than at the IBP site.Thaw depth
at the lowland was almost zero in Jme8and the permafrost dissolved up to a maximum depth of29cm
in early August,while the maximum depth at the bank was44cm at the same time(Fig.5).
52Daily,variations of heat budget com加nents
22 Misc.Publ.Natl.Inst。Agro-Envlron.Sci.,No。16(1995)
0
ハEo)10‘一αΦ
rσ
タ
㊦ 20‘←
30
却ロi
、
マテi
8’、・慈監周』
一●■]日Low Center
一△一一Ridge
■-血■■ice Wedge
_1_ _rO一一High Center_
周』亀i
i『」 99.… ?u
P㌔…
◎、『’、・
i竃蓄茜’一’
冬■■■■
ヨ∂唖
1・・猶瞬6
Fig.4
610 620 630 710 720 730 809 819 829
Date
Variations of thaw depth at the IBP site.Refer to Fig.3for characteristic surface
features.
ハεε
5岳℃
き
o‘←
O
10
20
30
40
50
ロー一Upland
…一Lowlandl一
i∋、駄 . _._..
響 o ●
■
「爆lll‡毒』融
620 630 710 720 730 809 819 Date
Fig.5 Variations of thaw depth at the Central Marsh site.
829
Harazonoε砲」.l Micrometeorological Data and Characteristics of Arctic Tundra in Alaska,1993 23
1)Heat budget analysis
The heat budget of a ground surface is given by the equation,
1~n=H+E+G (18〉
where Rn,H and認are the net radiation,sensible heat flux and Iatent heat flux(l is the latent heat
of the vaporization of liquid water and.E is the evaporation rate),and G is the heat flux through the
soil surface(W/m2).In the turbulent boundary layer,the diffusion velocity of water vapor is assumed
to be equal to that of heat(Monteith,1973)。The Bowen ratlo,βis defined as the ratio of sensible to
latent heat flux as the middle of equation(19).Thusβcan be determined from the gradients of
temperature and humidity as follows:
H △7乙
βrrγ△6、(19)
whereγis the psychrometric constant,and△7ムand△6a are vertical gradients of air temperature and
vapor pressure。Energy fluxes of∬and IE can be determin。ed using Bowen ratioβand measured values
ofノ~ηand G as follows:
1~究一G万=β 1+β
R%一〇E= 1+β
⑫0)
(21)
2)Typical results of heat budget over the tundra at the IBP site
Fig.6shows the daily pattems of the heat budget components,R%,昭,E and O at the IBP site
in mid-June(a),1ate June(b),mid-July(c),late July(d)and early August(e).
Before mid-July,the sensible heat flux H accounted for most of the net radiationノ~%,and the
contribution of latent heat flux to R%was sma1L The wind with low temperatures and high humidity
blew over the Arctic tundra frequently which caused hig且sensible heat flux.The contribution of E to
1~%was about75%,and that of IE was12%in the earlier half period of measurement(from June15to
July l7).
During the mid-summer(1ate-July)the daily maximum of the latent heat flux often exceeded
24 Misc.Pub1.Natl.Inst.AgroEnviron.Sci.,No.16(1995)
100W/m2,and its contribution toノ~n increases to34%.The contribution of H was about55%.
In the period of late-summer(from August)ノ~%decreased significantly which caused a decrease
of H and G,though the level of IE was almost the same as that of mid-summer(about3MJ/m2day).
The contribution of認to Rηwas44%,and that of H was45%.The increasing trend of昭was caused
by a deepening of the thaw depth as shown in Fig.4and Fig.5.
The contribution of soil heat flux G to Rn was within1145%for each clear day.
Harazono6砲1』Micrometeorological Data and Characteristics of Arctic Tundra in Alaska,1993
500
詮400∈\
タ300冥
コ
ζ200>、
91008山 0
-100
500
詮400∈\
タ300翼
コ
ζ200>、
9100窪] O
-100
500
詮400 ∈\……:300
冥 コ
ご200>、
9100 婁
田 0
-100
(a)Junl18
...一『Rn G一…・……p一
・一融△・一曾IE
.iコ.緯
・願..’1
0 6 12 18 Time of day(h)
24
㊥り嚇lo __一Rn…””
G ”」一齢合一.iE甲”』9…『””
』二『「…
.Llる1身1・’避隙;捧二』
..‘.弦二か廟駒
0 6 12 18 Time of day(h)
TT
24
塵勃』嫉15
一→一一Rn ..、一一G.. _瞬合一曹IE’一一畠』』’p
醒、陰
の しムr…9◎・‘……
i.二麓墜、.藁...
r ◎
0 6 12 18 Time of day(h)
24
25
26 Misc.Pub1.Natl.Inst.AgroEnviron.Sci.,No.16(1995)
詮 ∈ タ
冥
2}>、
o 』 Φ ⊆
田
500
400
300
200
100
0
一100
(d)Juli.25
一←一Rn1
一一G一一△・一・IE一一●一一H
1△”。贈9
イ翰み’」『丞“づ『
9i
・趣へ1
0 6 12 18 Time of day(h)
24
500
400
詮E\ 300タ
冥⊇ 200}>、
9100窪
u」
0
一100
(e) Au尊・5
一→一一Rn
一Gi’㌔一り∠y一一IE一H
θ
可ム『輔 冒■
O 6 12 18Time of day(h)
24
Fig。6 Daily variations of the heat budget components for representative days(a:mid-
June,b二late June,c=midJuly,d:late July,and e:early August)at the IBP site.
五~n:net radiation flux,H:sensible heat flux,1E:1atent heat flux,G:soil heat flux.
Harazonoα認.:Micrometeorological Data and Characteristics of Arctic Tundra in Alaska,1993 27
5.31ntra-season variation of the micrometeorological characteristics over the tmdra
Fig.7represents the seasonal trend of the daily summation of downward solar radiationノ~sゴnet
radiationノ~㌶,and soil heat flux O.Fig.8representsthe seasonal trends ofdaily average air temperature
ルand absolute humidity。4H of the air、(height2.l m),and Fig。9represents daily average wind speed
of the highest leve1αand wind direction(height4.7m)over the tundra.Daily average values were
calculated using each30minute average.
The daily accumulation ofsolarradiation accountedformorethan25MJ/m2perday onclear and
relatively Iow wind speed days in the earlier half of measurement(from ruid-Jme to midJuly)which
was almost the same as that measured at the central part of Japan in summer.Net radiation ranged
from8to18MJ/m2par day in late July,thendecreasedwithsolarradiation.Soilheatflux also changed
with Rs4and/or∫~η,but the amplitude of the fluctuation was smaller than those of Rs4and R%.The
long term trend of the contribution of G to Rn did not change remarkably those values ranging within
ll45%ofノ~”.The share ofノ~n to Rs4was smaller in the earlier half period of the measurement
compared to the Iatter half,because of the continuous solar radiation of the mid night sun.Solar energy
mainly contributed to sensible heat by Iate July,but after August there was a few clear days and
radiative cooling at night,thus the solar energy did not contribute to the sensible heat.
The amplitude of the daily average air temperature was large in mid summer,while the level of
absolute humidity did not change remarkably.The maximum alr temperature waもobserved in mid
July,which was almost three weeks after the peak of solar radiation.Higher air temperatures of more
than20℃were observed in the aftemoon under both low wind speed and.clear conditions,while,10wer
air temperatures of less than O℃were observed on windy and foggy days.
Windspeed overtheArctictundra wasrelativelyhighalmosteveryday,andsometimesthedaily
average exceeded10m/s,of which the hourly average exceeded15m/s.These high wind speed might
provide a large portlon of sensible heat,especially in the measurement period before mid-July。Wind
direction changed almost every day,and the dominant wind direction,which was different from the
dominant direction reported by Herbertαα1(1991),was northwest and east to southeast.
28 Misc,Publ.Nat1。Inst.Agro-Environ.Sci.,No.16(1995)
詮∈
\
3)⊆
oo冨
.9
-6匡
30
25
20
15
10
5
O
劉、
’猟甲1。1
1ぜ紘l i
壷
.-i一甲D
i一一Rsd’←一帥圃Rn’÷-
i一一G
騒
監
’÷一 量…
も
・籍1…
亀り1愚▲」i、
.璽_ ..i.蕉.
了墨i一置
6/15 7/1 7/17 Date
8/2 8/17
Fig.7 Variations of daily fluxes of solar radiation,net radiation and soil heat over the
Arctic dry tundra at the IBP site during the observation period.
Harazono6加1.:Micrometeorological Data and Characteristics of Arctic Tundra in Alaska,1993 29
lBP aveTrend615-825
25
20(り0 15)d∈ 10β
5
.k
《
0一5
び㌧一ら・貰一畢・」さ・、一=一一湘×
Humidity +ら一ド。
、,、
,『
・」『…・÷一
、 ノ..鷺.、.孟..諸.
、..、ノ.鷺 ~.”..響. も
i収r_”1’i
Temp.
15 詮
10 Ei も
)
5 >、 .ヒ
O 筥 E
5
=E
6/15 7/1 7/17 8/2 8/17Date
Fig.8 Variations of daily mean temperatureル,daily mean absolute humidity、4Hover the Arctic dry tundra of the IBP site.
30 Misc.Pub1.NatL Inst.Agro-Environ.Sci。,No.16(1995)
(o\ε
)で①Φ
αの
で.i≡
蓼
12
10
8
6
4
2
O
ll
一一×一一WD
ヨ
『1-i
、h l監i.!_1..1.玉.i。.!i
藁li’
~’
,
、、、..
’7
監
1 聾
監
’牲
不1 4 魁l l 隻..
J l 、 覧 J
l l 亀へ
l l Jl l 篭へ ’曾甲一{甲・ 一』。・
匪
、
竃
監
ロl P
ヤ
多甲甲
亀
n
-169r篭
i
i’
」
”苓へ…,1亀1’
τL峯…
“ 『
、
¥
印.L..◎.一甲
亀
、 ’i
l rl .↓...1.。藤1.9
径厚
“ 」
ノ
1一一u1
400 6
300Φ ε
200
100
O
⊆
o賜5
0①.ヒ
で
で.…≡
き
6/15 7/1 7/17 8/2 8/17Date
Fig.9 Variations of daily mean wind speed乙~(4.7m in height)and wind direction at the
IBP site.
Harazonoαα」』Micrometeorologic&1Data&nd Characteristics of Arctic Tundra in Alaska,!993 31
6.Data tables
Data are listed as an every30minute average except for the background CO2concentration,
B℃02.The dividing points of the averagings are10and40minutes,thereforethe data with a time Iabel
of OO were averaged between41minutes to10minutes of each hour.Only the backgromd CO2
concentrations listed with3time label of OO were averaged from Ol to60minutes of each hour.The
symbols are shown as followsl
Tal
Ta2
Ta3
AH!
AH2
AH3
RHl
RH2
RH3
Tsl
Ts2
Ts3
Ts4
Rsd
Rsu
Rn
G
UVb
PAR
Albedo
Ul
U3
U5
air temperature(℃)at the highest level of measurement
air temperature(℃)at the middle level of measurement
air temperature(℃)at the lowest level of measurement
absolute humidity(g/m3)of the air at the highest level
absolute humidity(g/m3)of the air at the middle level
absolute humidity(g/m3)of the air at the lowest level
relative humidity(%)of the air at the highest level
relative humidity(%)of the air at the middle level
relative humidity(%)of the air at the highest level
soil temperature(℃)at l cm depth below the surface
soil temperature(℃)at5cm depth below the surface
soil temperature(℃)at lO cm depth below the surface
soil temperature(℃)at20cm depth below the surface
solar radiation(W/m2)(downward)
reflection of solar r&diation(W/m2)(upward)
net radiation(W/m2)
soil heat flux(W/m2)
ultra violet radiation(W/m2)
photosynthetic active radiation(、μE/sm2)
Albedo;Rsu/Rsd
wind speed(m/s)at the top measurement height
wind speed(m/s)at the middle level
wind speed(m/s)at the lowest measurement盤eight
32 Misc,Pub1.Nat1.Inst.Agro-Environ.Sci.,No,16(1995)
WDZO
賑
Ri
Df
CO2
B-CO2
wind direction(deg)specified from O to360degrees with clockwise rotation from north
roughness parameter(roughness length)(cm)over the tundra
friction velocity(m/s)over the tundra
Richardson number
diffusion velocity(cm/s)over the tmdra
CO2concentration(ppm)over the tundra(at the same height of Tal)
Background CO2concentration(ppm)measured by CMDL/NOAA.
A mark shown in this column is represented in section4。1.
Harazono6砲1』Micrometeorological Data and Characteristlcs of Arctic Tundra in Alaska,1993 33
7.Acknowledgments
This observational study was conducted as a collaboration between the Global Change Research
Group of San Diego State University(SDSU)(Director,Prof.Walter C.Oeche1)and the Division of
Meteorology,National Institute of Agro-Environmental Sciences(NIAES).Budgetary support was
provid.ed by the Science and Technology Agency Japan(STA)and the San Diego State University
Foundation.The Department ofWildlife Management,North Slope Borough(DWM/NSB),Barrow at
Northem Arctic Research Laboratory(NARL)supported the observation by providing us with a
laboratory,mechanic shop and accommodation facilities at the Arctic Research Facility(ARF)。The
authors acknowledge the persons of the above organizations,especially Mr.Benjamin P.Nageak,
Director of the Department of Wildlife Mallagement/NSB and Dr.George Craig ofARF/DWM/NBS.
Regarding the background CO2data,we thank Dr.Daniel J.Endres of the Climatic Monitoring and
Diagnostic Laboratory(CMDL),Barrow Station/NOAA,and Dr.Pieter Tans of CMDL,Boulder/
NOAA for their efforts.
We also thank Mrs.Hiromi Matsubara,from the Lab.ofmicrometeorology,NIAES forherhelp
with data processing,to Dr.Seisi Isobe,head of the meteorology division,NIAES and to Mr.Steven J.
Hasting,Department of Biology/SDSU for their useful comments,to Dr.Susumu Sugihara and the staff
of the Intemational and Domestic Liaison division of NIAES,and to persons comected with the
Intemational Research Division,of the Agriculture,Forestry and Fisheri“s Research Council Secretar-
iat,MAFF for their support for this observational study,
34 Misc.Pub1.Nat1.Inst.Agro-Environ.Sci.,No.16(1995)
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