Bulletin of Glaciological Research ,0 (,**2) +/ῌ,+ῌJapanese Society of Snow and Ice

15

Chemical Characteristics of Snowpack due to Di#erences in Snowfall Type in Japan
Alps
Takayuki KURAMOTO+, Shailendra Kumar SHAH+, Motoki TANAKA, and Keisuke SUZUKI+, ,+ Department of Environmental Sciences, Faculty of Science, Shinshu University, Asahi, Matsumoto -3*ῌ20,+, Japan, Institute of Mountain Science, Shinshu University, Asahi, Matsumoto -3*ῌ20,+, Japan(Received February +/, ,**2; Revised manuscript accepted May ,1, ,**2)

Abstract
We conducted a snow survey in February ,**0 and January ,**1 in Japan Alps. Approximately*.0* m and +.*/ m snowfalls were deposited at the study site in February ,**0 and January ,**1,
respectively. It was observed that the occurrence of snowfall was due to the low pressure formationin the vicinity of Japan and it also being the winter monsoon period. As a result of the analyzed
snowpack, including new snow at a high resolution every *.*- m, a plurality of high-electric conductivity layers were observed at di#erent depths. From the measurement of the major ion concentrations, it was observed that the high-electric conductivity layers had di#erent chemical characteristics.
High concentrations of NO-῍ and SO.,῍ deposits were observed in the snowpack layer that was formed
due to the low-pressure system that passed in the vicinity of Japan. On the other hand, the layer thatformed during the winter monsoon pattern, large amounts of sea salts were deposited in the snowpack
in January ,**1. However, layers with a high sea-salt concentration were not observed in February,**0. We analyzed the movement of the air mass that ﬂowed into the study area. Air mass passed
through the city at the time of the passage of the low-pressure system. In addition, the air mass thatcrossed the Sea of Japan entered the study area during the winter monsoon pattern. However, themovement of the air mass was di#erent during the winter monsoon pattern in February ,**0 andJanuary ,**1.

+.

Introduction

The chemical components accumulated with snowfall during the winter season are stored in the snowpack. The accumulated chemical components are
separated by the process when the snow particle metamorphoses into the surface of the snow particle andbegins to ﬂow out with the snowmelt water (Suzuki,+330; Suzuki, ,***). The snowmelt water ﬂow in theearly snowmelt period begins to dissolve the chemicalcomponents at the surface of the snow particle. Therefore, many chemical components are included in thesnowmelt water that begins to ﬂow out in this period.
The acidiﬁcation occurs temporarily in the river as
the snowmelt water ﬂows out (Kuramoto and Suzuki,,**0).
A study on the weather conditions and winterprecipitation was performed. Suzuki (+32-, +32.) collected the winter precipitation and snowpack of one
winter season in Sapporo, Hokkaido prefecture. The
origin of the chemical components was examined in
the sample. SO.,῍ was inﬂuenced by the use of fossil
fuels in Sapporo, whereas Naῌ and Cl῍ were sea salt.

Suzuki and Endo (+33.a, +33.b) collected winter precipitation samples everyday in Tohkamachi, Niigata
prefecture. The chemical characteristics of the samples and the weather conditions were investigated.
Large amounts of sea salt were deposited during thewinter monsoon pattern and large amounts of acidcontaining materials were deposited when a lowpressure system passed the south coast of Japan.
There is no outbreak source near the mountainous regions. The pollutants from the neighborhood
are not deposited in these regions. In addition, theweather condition changes with time. Therefore, sampling at short intervals of time is necessary to examine a detailed change. However, if the area does notpass through the snowmelt process, it is thought thatthe chemicals originating from the precipitation isstored and accumulated intermittently. The chemical components preserved in the snowpack of themountainous region can be obtained through various
atmospheric information. However, it is di$cult toclarify the exact time scale of the deposited snow ineach layer where there is little availability of meteorological observation data in the mountainous region.
Therefore, the presumption of the deposition period

16

Bulletin of Glaciological Researchhas been done so far by using various techniques.
For example, a method to estimate the deposition
period was reported with the sea salt components ord+2O in the snowpack at Mt. Tateyama, which is aheavy snowfall mountainous region located in the Sea
of Japan side (Kido et al., +331, Toyama et al., ,**/).
Nishita et al. (,**1) studied the transportation process of aerosols during summer in Mt. Norikura. The
air mass ﬂowed from the Paciﬁc and the Asian Continent and it became clear aerosol was di#erent by an
air mass. However, the author did not discuss thedi#erence in the chemical property resulting fromdi#erences in the air mass composition. In the Sea ofJapan side, considerable winter precipitation was observed; that is, mainly two patterns such as the wintermonsoon pattern and low pressure pattern that passed over the Sea of Japan. On the other hand, winterprecipitation occurs due to the passage of the lowpressure system along the south coast of Japan in the
Paciﬁc side. The Japan Alps area is the backbone ofJapan where precipitation is observed under bothconditions during the entire winter season. The different course of water bringing these precipitations isthought to be the di#erent sources of ion species
included in the snowpack. In the Sea of Japan coastal area, many ion species are included in the precipitation, and it is reported that the pH of the winterprecipitation is low (Satow, +33-; Suzuki and Endo,+33.b). Toyama et al., (,**1) studied the origin of
nss-SO.,ῌ in the snowpack on the basis of d-.S and the
S/N ratio at the Mt. Nishi-Hodaka, Japan Alps. The
assumption that the ion species included in the snowpack depend on the di#erent snowfall types for estimating the deposition period. In this study, we conducted a multiple snow survey at the eastern slope of
Mt. Norikura in the Japan Alps between the winterseason of ,**0 and ,**1. The purpose of this study is
to clarify the chemical characteristics of the snowpack by di#erent snowfall types.

Fig. +.

,.

Methods

Mt. Norikura (-*,0 m a.s.l.) is located in the southernmost part of the northern Japan Alps. The sampling site (+/3* m a.s.l.) is located at the eastern slopeof Mt. Norikura (Fig. +). It is at the foot of the mountain and is formed by lava.
The meteorological observation devices were set
up at the sampling site; the air temperature and snow
depth were measured automatically. Moreover, theprecipitation was measured with a tipping-bucket rain
gauge set up at Norikura station (+..* m a.s.l.), Instituteof Mountain Science, Shinshu University, that was
located approximately , km northeast from the sampling site. The annual mean air temperature that we
observed in sampling site was 0.-῍, the annual precipitation was ,/,/./ mm, and the winter season precipitation observed from December to March was /0../ mm in
Norikura station in ,**0. The study site is approximately / km from the top of Mt. Norikura. The prevailing wind of winter blows from the northwest inJapan Alps. In the sampling site, northwest wind isobserved in the winter season. Therefore, it isthought that a local inﬂuence can be disregarded. We
considered the study area to represent the eastern
slope of Mt. Norikura.
A heavy snowfall was observed to occur in the
study area in February ,**0 and January ,**1. The
snow samples were collected before and after thesnowfall. The snow pits were dug up to the groundlevel for the sample collection. Afterwards, the samples were collected from the snow surface layer to theground level at intervals of *.*- m. A cube-type snow
sampler made of stainless steel and having a height of*.*- m was used for the sample collection. The sample was inserted into a sample bag (Nasco: Whirl-pak)and sealed to be transported to the laboratory. Samples were preserved without melting in a deep refrigerator until their analysis. They were allowed to

Location map of Mt. Norikura (left) and a detailed map of the study site (right).

Kuramoto et al.

Fig. ,.

Change of weather chart from January 0 to 3, ,**1 (Source: Japan Meteorological Agency, ,**1).

melt at room temperature before the analysis. The
pH, electric conductivity, and major ions (Naῌ, NH.ῌ,Kῌ, Mg,ῌ, Ca,ῌ, Cl῍, NO-῍, SO.,῍) were measured withthe pH meter, conductivity meter, and ion chromatograph (Dionex: DX-/**), respectively. All the analytical work was performed in a clean room.

-.

17

Results and Discussion

inﬂuence of the strong winter monsoon pattern. The
precipitation observed the study site on January 0,,**1 was ,/./ mm. The precipitation observed on
January 1 and 2, ,**1, was ,0.* mm and 0./ mm, respectively. The snow depth began to increase from January 0, ,**1, and it reached up to +.-/ m on January 2,,**1, at 2 : ** (JST).
Figure . shows the vertical proﬁles of the pH andelectric conductivity in the snowpack sampled on

An increase in snowfall of approximately +.*/ m
was observed at the study site on January 0 to 2, ,**1.
Figure , shows the ground weather chart in the vicinity of Japan from January 0 to 3, ,**1. The lowpressure system passed along the Sea of Japan andthe south coast of Japan on January 0, ,**1. Afterwards, it intensiﬁed while moving northwards and astrong winter monsoon pattern developed in the vicinity of Japan. From January 1 to 2, ,**1, the vicinity of Japan was covered by the strong winter monsoon. Figure - shows the changes in the precipitation, air temperature, and snow depth from January /to 3, ,**1. The air temperature during daytime had
increased on January 0, ,**1. However, the air temperature decreased during the day on January 1 and 2,,**1, because the vicinity of Japan was under the

Fig. -. Variations in precipitation, air temperature,and snow depth from January / to 3, ,**1.

Fig. .. Vertical proﬁles representing electric conductivity and pH in snowpack samples obtained on
January / and January 3, ,**1.

18Bulletin of Glaciological Research

Fig. /.

Vertical proﬁles representing electric conductivity, pH, and major ion concentrations in snowpack samples.

January / and January 3, ,**1. The snow depths at
the sampling time on January / and January 3, ,**1
were *.-0 m and +.+/ m, respectively. The proﬁles ofthe pH and electric conductivity of the snowpack
resembled those in the layer lower than approximately *.-/ m. From this, we understand that the
new snow layer was greater by approximately *.-/ m
on January 3, ,**1.
Figure / shows the vertical proﬁles of the pH,
electric conductivity, and concentrations of major
ions in the snowpack sampled on January 3, ,**1. In
the new snow layers, we observed high-electric conductivities in some layers at approximately *.// m;however, the pH was low in the same layer. In thislayer, the concentrations of NO-ῌ and SO.,ῌ were high.
Therefore, the pH was decreased and the electric conductivity was increased. The neighboring layer of*.// m can estimate the snowfall on January 0 ,**1from the precipitation and a change in snow depth
point of view. Therefore, we analyzed pattern of the
trajectory in order to examine the course of the movement of air masses by the data obtained from CGERMETEX (NIES-CGER). The precipitation reached thehighest at +, : ** (JST) on January 0, ,**1, in thevicinity of the study area. We analyzed this by employing an isentropic method and show the pattern oftrajectory for the past four days. We used the analysis results obtained from the pattern of trajectory andshowed the course of movement of the air mass thatdrifted into the study area at +, : ** (JST) on January
0, ,**1 (Fig. 0a). The plots in Fig. 0a are shown atintervals of +, h. We understand from the pattern oftrajectory that the air mass that began to ﬂow fromthe Asian continent on January ,, ,**1, passed thesouth coast of the Kyushu and Chubu regions andthen arrived in the study area. From this, it is thoughtthat the chemicals that occurred in an area westwardof the Chubu region were brought with an air massinto the study area when the low-pressure system
passed along the south coast of Japan.
On the other hand, a high-electric conductivity
was observed in the layers of the snow depth ofFig. 0. Air mass back-trajectory generated using the
CGER-METEX model for winter precipitation observed at sampling site. ῌ denotes every +, h. (a)Low-pressure system that passed in vicinity ofJapan ending on January 0, ,**1, at +, : ** (JST),(b) Winter monsoon pattern ending on January 2,,**1, at . : ** (JST).

Kuramoto et al.

approximately *.1* m and *.3* m. In these layers, thedecrease in the pH and the remarkable increase in theNO-῍ and SO.,῍ concentrations were not observed.
However, the Naῌ and Cl῍ concentrations increased
remarkably. We can estimate that it is the snow thatwas deposited on January 1 to 2, ,**1, when the vicinity of Japan was under the strong winter monsoon
pattern; these layers occur due to the precipitationand the change in the snow depth. We used thepattern of trajectory analysis results and obtained thecourse of the movement of the air mass at the time ofthe snowfall at . : ** (JST) on January 2, ,**1 (Fig. 0b).
When an air mass passes the Sea of Japan, the sea salt
substances, included in the atmosphere by the northwest periodic wind, are carried to the study area. It isthought that the layers of high Naῌ and Cl῍ concentrations originated from sea salts. On the other hand,a remarkable increase in NO-῍ is not observed.
In the study area, heavy snow was observed in
February ,**0. Figure 1 shows the change in the
precipitation, air temperature, and snow depth fromFebruary , to 2, ,**0. Precipitation was observed on
February - and from February 0 to 2, ,**0. The air

Fig. 1. Variations in precipitation, air temperature,and snow depth from February , to 2, ,**0.

Fig. 2.

19

temperature decreased in this period. Therefore, it
was thought that the study area received snowfall.
The precipitation observed at the study site during
the latter half of the period from February 0 to 2, ,**1,
was ,-./ mm. The snow depth begins to increase
from February 0, ,**0, when precipitation was observed, and it reaches +.03 m on February 2, ,**0, at +1:** (JST). Figure 2 shows the ground weather chart in
the vicinity of Japan from January 0 to 2, ,**0. The
low-pressure system passed along the south coast ofJapan. This low-pressure system intensiﬁes while
going northwards and the winter monsoon patterndevelops in the vicinity of Japan.
Figure 3 shows the vertical proﬁles representing
the pH and electric conductivity in the snowpacksampled on February , and February 2, ,**0. The
snow depths at the sampling time on February , andFebruary 2, ,**0, were +.*/ m and +..1 m respectively.
The proﬁles of the pH and electric conductivity of thesnowpack resembled in the layer lower than approximately *.3* m on February , and February 2, ,**0.
From this, we understand that the new snow layer
had a thickness of approximately *.3* m on February
2, ,**0.
Figure +* shows the vertical proﬁles of the pH,
electric conductivity, and concentrations of major
ions in the snowpack sampled on February 2, ,**0.
In the new snow layer, we observed high-electric conductivities in some layers at depths of approximately*.3/ m and +.+/ m. Similar to the layer observed at a
depth of approximately *.// m on January ,**1, thepH was lowered and the NO-῍ and SO.,῍ concentrations were high in these layers. The neighboringlayer of +.+/ m can estimate the snowfall on February
0, ,**0 from the precipitation and a change in snow
depth point of view. We analyzed the pattern oftrajectory to examine the course of the movement of
air masses. On February 0, ,**0, it was at +*: ** (JST)when the precipitation began to fall in the vicinity ofthe study area. We analyzed this by employing an
isentropic method and showed the pattern of trajectory for the past three days (Fig. ++a). We learnt
from the pattern of trajectory that the air mass thatbegan to ﬂow from the Asian continent on February .,Change of weather chart for February 0 to 2, ,**0 (Source: Japan Meteorological Agency, ,**0).

20

Bulletin of Glaciological Research,**0, passed the Yellow Sea and the West Japan region, and then, it entered the study area. From this,
it is thought that the concentrations of ion species
that occurred in the West Japan region were broughtwith an air mass to the study area when the lowpressure system passed along the south coast ofJapan.

On the other hand, remarkably high-concentration
layers of Naῌ and Cl῍, as observed on January ,**1,
were not observed. We used the pattern of trajectory
analysis results and obtained the course of the movement of air masses when the vicinity of Japan wasunder the winter monsoon pattern at 3: ** (JST) on
February 2, ,**0 (Fig. ++b). It is understood that the
air mass that ﬂowed into the study area at 3: ** (JST)on February 2, ,**0, came from the west as comparedto that observed on January ,**1. It is thought thatthe air mass was caused due to the weak developmentof the low-pressure system in February ,**0 as compared with January ,**1. Therefore, there are little
sea salt components taken in the atmosphere by thenorthwest periodic wind. It is thought that the layer
did not form high concentrations of sea salt components such as Naῌ and Cl῍ in the study area.

..

Fig. 3. Vertical proﬁles representing electric conductivity and pH in snowpack samples obtained on
February , and February 2, ,**0.

Fig. +*.

Conclusion

A heavy snowfall was observed in eastern slopeof Mt. Norikura in February ,**0 and January ,**1.
We conducted the snow survey before and after thesnowfall. The low-pressure system observed in February ,**0 and January ,**1 developed in the vicinityof Japan. Approximately *.0* m and +.*/ m of snowfall was deposited in sampling site, respectively. The
chemical characteristic di#ered with the depth in the
new snow layer. At the time of this snowfall event,there was an inﬂuence on the course of two di#erent
air masses in the study area. When the low-pressure
system passed the vicinity of Japan, the air mass
ﬂowed through the West Japan region into the study
area. For the snow layer that accumulated in thisperiod, large amounts of NO-῍ and SO.,῍ were deposited that was considered as the outbreak source in theWest Japan region. On the other hand, there was an
air mass crossing the Sea of Japan from the AsianContinent when the vicinity of Japan was under thestrong winter monsoon pattern. In January ,**1, alarge amount of sea salt substances were deposited in
the layers, where they accumulated. However, highVertical proﬁles representing electric conductivity, pH, and major ion concentrations in snowpack samples.

Kuramoto et al.

21

ciety for the Promotion of Science, and it was also
supported by the Global Environment Research Fund
(C-0 and C-*/,) of the Japanese Ministry of the Environment.

References

Fig. ++. Air mass back-trajectory generated using the
CGER-METEX model for winter precipitation observed at sampling site. ῌ denotes every +, h. (a)Low-pressure system that passed the vicinity ofJapan ending on February 0, ,**1, at +* : ** (JST),(b) Winter monsoon pattern ending on February 2,,**1, at 3 : ** (JST).

sea salt concentration layers were not observed in
February ,**0. The low-pressure system intensiﬁed
in January ,**1. As a result, it is thought that thereason is because many sea salt components werecarried by a strong northwest periodic wind. The
snowfall observed in the Japan Alps area was a characteristic of di#erent chemical components broughtin the case of a strong winter monsoon pattern andlow pressure pattern in the vicinity of Japan.

Acknowledgements
We are grateful to editor and an anonymous reviewer for their valuable advices and comments.
This research was supported by a Grant-in-Aid for
Scientiﬁc Research (No. +1-+***1) from the Japan So-

Japan Meteorological Agency (,**0): Weather statistics information, weather chart. http://www.data.jma. go.jp/
fcd/yoho/hibiten/index.html. (In Japanese)
Japan Meteorological Agency (,**1): Weather statistics information, weather chart. http://www.data.jma. go.jp/
fcd/yoho/hibiten/index.html. (In Japanese)
Kido, M., Osada, K., Yabuki, H. and IIDA, H. (+331): Dating of
seasonal layers at Murodo, Mt. Tateyama, Japan.
Seppyo, /3, +2+ῌ+22. (In Japanese with English abstract)
Kuramoto, T. and Suzuki, K. (,**0): Chemical dynamics ofsnow and stream water in the Japanese Alps. Seppyo, 02,.01ῌ.2*. (In Japanese with English abstract)
NIES-CGER: National Institute for Environmental StudiesCenter for Global Environmental Research. http://db.
cger.nies.go.jp/metex/index.jp.html
Nishita, C., Osada, K., Matsunaga, K. and Iwasaka, Y. (,**1):
Number-size distributions of free tropospheric aerosol
particles at Mt. Norikura, Japan: E#ects of precipitation
and air mass transportation pathways. Journal of Geophysical Research, ++,, D+*,+-, doi: +*.+*,3/,**0JD**1303.
Satow, K. (+33-): Chemical characteristics of snow in theregion along the Sea of Japan. Annals of Glaciology, +2,,,1ῌ,--.
Suzuki, K. (+32-): A chemical study of snow in Sapporo.
Geographical review of Japan, /0, +1+ῌ+2.. (in Japanesewith English abstract)
Suzuki, K. (+32.): Spatial distribution of concentration of chemical constituent in the snow cover. Geographical review
of Japan, /1, -.3ῌ-0+. (in Japanese with English abstract)
Suzuki, K. (+330): Chemistry of stream water in a snowy
temperate watershed. Journal of Geography, +*/, +ῌ+..
(in Japanese with English abstract)
Suzuki, K. (,***): Review on snow chemistry in Japan.
Seppyo, 0,, +2/ῌ+30. (In Japanese with English abstract)
Suzuki, K. and Endo, Y. (+33.a): Sea salt originated material
in winter precipitation and weather condition. Seppyo,/0, ,--ῌ,.+. (In Japanese with English abstract)
Suzuki, K. and Endo, Y. (+33.b): Concentration changes ofacidic ions in winter precipitation in Tohkamachi,
Japan. Quarterly Journal of Geography, .0, +0+ῌ+1,. (InJapanese with English abstract)
Toyama, K., Suzuki, G., Satake, H., Kawada, K. and Iida, H.
(,**/): Dating of snow layers in the mountain area basedon the variation of oxygen isotope ratio. Seppyo, 01, -+3
ῌ--*. (In Japanese with English abstract)
Toyama, K., Satake, H., Takashima, S., Matsuda, T., Tsuruta,
M. and Kawada, K. (,**1): Long-range transportation ofcontaminants from the Asian Continent to The Northern
Japan Alps, recorded in snow cover on Mt. NishiHodaka-Dake. Bulletin of Glaciological Research, ,., -1ῌ
,..