13

Recent Glacier Shrinkages in the Lunana Region, Bhutan Himalayas
Nozomu NAITO1*, Ryohei SUZUKI2, Jiro KOMORI3, Yoshihiro MATSUDA4,
Satoru YAMAGUCHI5, Takanobu SAWAGAKI6, Phuntsho TSHERING7 andKharka Singh GHALLEY7
1

Department of Global Environment Studies, Hiroshima Institute of Technology,
2-1-1, Miyake, Saeki-ku, Hiroshima 731-5193, Japan
2
Shin-Yokohama Office, Fujitsu Software Technologies Co.Ltd., Yokohama 222-0033, Japan
3
Graduate School of Environmental Studies, Nagoya University, Nagoya 464-8601, Japan(Present affiliation: Department of Modern Life, Teikyo Heisei University)
4
Hydrospheric Atmospheric Research Center, Nagoya University, Nagoya 464-8601, Japan
5
Snow and Ice Research Center, National Research Institute for Earth Science and Disaster Prevention,
Nagaoka 940-0821, Japan
6
Faculty of Environmental Earth Science, Hokkaido University, Sapporo 060-0810, Japan
7
Department of Geology and Mines, Ministry of Economic Affairs, P.O.Box 173, Thimphu, Bhutan*e-mail: naito@cc.it-hiroshima.ac.jp

Abstract
Two debris-covered glaciers and two debris-free glaciers were surveyed regarding their surface loweringin the Lunana region, in the northern part of Bhutan. Regarding the debris-covered ones, the lowering rates
were estimated to be 0-3 m a-1 and approximately 5 m a-1 on the ablation areas of the Thorthormi and Lugge
Glaciers, respectively, in 2002-2004. Glacier flow was also measured for the two glaciers. The results showed
contrastively that compressive flow is clear on the Thorthormi Glacier but not on the Lugge Glacier. The
contrast in the surface lowering and flow is discussed herein to infer a positive feedback mechanism between
glacier shrinkage and glacial lake growth.
On the other hand, the surface lowering rates evaluated on debris-free glaciers were 3-4 m a-1 on thelower part of the Jichu Dramo Glacier in 2003-2010, and 1-3 m a-1 on a small unnamed glacier southeast of the
Jaze La (pass) in 1999-2010. The lowering rate on the Jichu Dramo Glacier may have accelerated from theprevious estimate in 1998-2003. In addition, several pairs of repeated photos are provided to show glaciershrinkages and retreats.
Key words: Bhutan Himalayas, debris-covered/-free glacier, field survey, glacier variation

1. Introduction
The variations of mountain glaciers and ice caps
worldwide have recently attracted considerable attention
due to their significance with respect to rising sea levels.
Summer-accumulation type glaciers in the Asian highland regions, including the Himalayas, are considered tobe particularly vulnerable to global warming (Ageta,
1983; Fujita & Ageta, 2000; Naito et al., 2001). This isbecause snowfall during summer can easily transform
into rainfall, and the decrease in fresh snow can reduce
the surface albedo of glaciers, which can lead to lesser
accumulation and greater ablation of the glaciers. In
reality, relatively rapid glacier shrinkages have beenreported in the Nepal Himalayas (e.g., Fujita et al., 1997;
Naito et al., 2002). On the other hand, Bhutan, which islocated near the eastern edge of the Himalayan range,
receives heavier precipitation than Nepal (Eguchi, 1994)
Global Environmental Research
16/2012: 13-22
printed in Japandue to a stronger influence of the Asian summer monsoon.
Karma et al. (2003) reported that the recent retreat rates
of glacier termini in Bhutan are almost twice as large as
those of glacier termini in eastern Nepal obtained by
Asahi (1999); further, they suggested that these differences may have resulted from the stronger influence ofthe summer monsoon in Bhutan.
In order to evaluate the volumetric glacier shrinkage,gauging the magnitudes of not only the retreating area but
also the lowering surface level is required. The rate oflowering of the glacier surface has been reported in
Bhutan, thus far, only by Naito et al. (2006), who estimated it for a debris-free glacier, the Jichu Dramo Glacierfrom 1998 to 2003. The present paper reports the observational results of glacier shrinkages in Bhutan, including the surface lowering rates of two debris-covered
glaciers and two debris-free glaciers, as well as repeatedphoto pairs showing terminal retreats of some other©2012 AIRIES

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N. NAITO et al.

debris-free glaciers.
In addition to the global issue of sea level rise, glaciervariations are related to local issues, too. Glacial lake
outburst floods (GLOFs) are a crucial problem faced byregional countries and people in the Himalayas (Yamada,
1998; Ageta et al., 2000). Potentially dangerous glaciallakes usually grow on the terminal part of debris-covered
glaciers (Yamada, 1998; Iwata et al., 2002), while theglaciers themselves shrink and moraines dam up the melt
water. Expansion of the glacial lake is normally considered to be a result of glacier shrinkage. The present
paper discusses the effect of glacial lakes upon glaciershrinkage, based on the observational results for two
debris-covered glaciers.

2. Study Area and Methods

lateral moraine ridges as shown in Fig. 2. Locations of
the surveyed points on the glacier surface were determined with a prism brought manually, though those of
the terminal ice cliffs of the Lugge Glacier were surveyed
by triangulation from two benchmarks on both lateralmoraine ridges beside Lugge Tsho. In addition, bamboo
stakes were installed on the glacier surface with a steam
drill in 2002 and 2003. All the stakes were found to havefallen down due to considerable ice melting the next year,
unfortunately. By surveying their root locations in 2003
and 2004, the surface glacier flow could be estimated.
Su rveyed line
Be nch markThor thor mi Gl.

Lugge Gl.

The study area in the present paper is located in thenorthern part of Bhutan (Fig. 1), the so-called Lunana
region, around the headwaters of the eastern branch of
the Pho Chu (river). Several debris-covered glaciers andglacial lakes are closely distributed in the northeasternpart of the area. Two debris-covered glaciers among them,
the Thorthormi and Lugge Glaciers, are the present
targets. An enlarged satellite image of them is shown in
Fig. 2. A huge glacial lake, Lugge Tsho (lake), is locatedin front of the Lugge Glacier, while many relatively small
supraglacial ponds are distributed on the debris-covered
ablation area of the Thorthormi Glacier.
Surface topography was surveyed on the ablation
areas of the two glaciers each autumn in 2002 - 2004,
using a total station system, the SOKIA SET 2000 series.
Benchmarks for the topographical survey were set on theFig. 2 The two debris-covered glaciers studied in the present
paper. The background is the same image as Fig. 1,
enlarged.

Fig. 1 Satellite image of the present study area; the Lunana
region in the northern part of Bhutan. Blue and yellow
dashed rectangles indicate the areas shown in Figs. 2
and 3, respectively. The background is an ALOS
AVNIR-2 10 m mosaic image composited from captured
data on Dec. 26, 2007 (right to central part) and Jan. 17,
2010 (left part) by Tadono et al. (2012).

Fig. 3 The high plateau region, where many debris-freeglaciers are distributed. Each number and letter attached
to a glacier is explained in the text. The background is
the same image as Fig. 1, enlarged.

2 km

Lugge Tsho

Recent Glacier Shrinkages in the Lunana Region, Bhutan Himalayas

On the other hand, the southeast of the Lunana region(Fig. 1) is a high plateau area spreading around theboundary between the Pho Chu and Mangde Chu basins,
where many debris-free glaciers are distributed. The
enlarged satellite image covering this area is shown in
Fig. 3. The surface topography of three debris-freeglaciers was surveyed in the autumn of 2010, using portable GPS receivers, the Magellan Promark 3. The GPS
measurements were post-processed using base station
GPS data. The GPS survey was intended to be carried out
as widely as possible on the glaciers, but bad conditions
for receiving GPS signals and some mechanical troubles
in the GPS receivers sometimes limited the measurements on part of the glaciers, unfortunately. Among thethree glaciers, the Jichu Dramo Glacier had been surveyed before in 1998, 1999 and 2003. Another small
glacier, numbered 1 in Fig. 3, had also been surveyed in
1999. The previous surveys on the two glaciers can beseen in Naito et al. (2006). The present paper describes
the changes in these two debris-free glaciers. The otherdebris-free glacier surveyed in 2010 is indicated with theletter “S” in Fig. 3, and is expected to be surveyed in the
future in order to evaluate its variation.
In addition to the quantitative topographical survey,
simpler observations of glacier variation were carried out
by taking repeated photos. The present paper presents acomparison of the repeated photos for four representativedebris-free glaciers, which are numbered 2 - 5 in Fig. 3.
Repeated photos were also taken of other debris-freeglaciers, indicated with the letter “P” in Fig. 3.

15

Fig. 4 Longitudinal profile of the surveyed ogive bands along
the upstream part of the longitudinal line on the ablation
area of the Thorthormi Glacier, shown in Fig. 2. The
abscissa is the longitudinal distance relative to thelocation of the cross-point with the transversal survey
line of 2002, setting positive upstream. The thick dashedlines represent the linear regression of each year’s
profiles, the equations of which are also displayed.

3. Results and Discussions
3.1 Debris-covered glaciers
3.1.1 The Thorthormi Glacier
A topographical survey was performed along one
longitudinal and one transversal line on the ablation areaof the Thorthormi Glacier, as shown in Fig. 2. The
upstream part of the longitudinal line from its crossing
point to the transversal line is bared with glacier ice, anda clear ogive has developed. Ten bands of the ogive weresurveyed at the location of each ridge and trough. The
longitudinal profile of the ogive bands is shown in Fig. 4.
The regression lines for each profile represent the averaged surface levels. The surface uplifting upstream andlowering downstream in 2002 - 2003 cannot be considered significant, and thus no significant change in thesurface level was confirmed for 2002 - 2003. A surface
lowering of approximately 3 m, however, could berecognized in 2003 - 2004. Ultimately, the surface lowering rate on this part of the Thorthormi Glacier could beconsidered 0 - 3 m a-1 in 2002 - 2004.
The horizontal flow speed was also estimated on theablation area of the Thorthormi Glacier, as shown in
Fig. 5. Three stakes that had been installed on the ridgesof the ogive bands in 2002 were found in theirdownstream trough in 2003. Their locations in 2003 werecorrected to the original ridges upstream. The accuracy ofthe modified speeds at the three stakes, thus, will be

Fig. 5 Longitudinal distribution of the horizontal surface flow
speed on the ablation area of the Thorthormi Glacier. The
abscissa is the same as that in Fig. 4.

lower than that at the other stakes. They are indicated byblank triangle marks in Fig. 5. The flow speed decreases
downstream. Such a compressive flow is typical on
ablation areas of glaciers and generates an upward emergence velocity. The above-mentioned surface lowering
rate is a result of the compensation between this emergence velocity and surface ablation.
3.1.2 The Lugge Glacier
A topographical survey was also performed on theablation area of the Lugge Glacier, as shown in Fig. 2. Asa matter of fact, the longitudinal survey line in Fig. 2
differed between 2002 and 2003. A bare-ice ridge
extending downstream was surveyed in 2002; here it istentatively called Ridge 1. Another bare-ice ridge at theleft bank side of Ridge 1 was surveyed in 2003; its

16

N. NAITO et al.

tentative name is Ridge 2. The two ridges are almost
parallel with a transversal spacing of approximately 50 m.
As both ridges were surveyed in 2004, the change insurface level can be evaluated on both. A longitudinal
profile of the ridges is presented in Fig. 6 with all
regression lines. A clear lowering can be found on bothridges. The surface lowering rates on these ridges turned
out to be equivalent; approximately 5 m a-1. This rateis fairly large compared to that on the neighboring
Thorthormi Glacier, 0 - 3 m a-1.
The horizontal flow speed estimated on the ablation
area of the Lugge Glacier is shown in Fig. 7. The flow
speed is relatively uniform at roughly 40 - 55 m a-1. This
result on the Lugge Glacier is contrastive to the clear
compressive flow on the Thorthormi Glacier, seen in
Fig. 5. The contrast in the glacier flow and shrinkage ofthe two glaciers is discussed below in subsection 3.1.3.
The horizontal location of the terminal ice cliff of the
Lugge Glacier was surveyed in 2002 and 2003. The
survey results indicate a rapid terminal retreat of 30 50 m a-1. Considering the glacier flow speed of 40 - 55 m
a-1 near the terminus, shown in Fig. 7, the calving ratefrom the glacier terminal cliff into Lugge Tsho is considered to be a very large value of 70 - 100 m a-1.
3.1.3 Feedback between glacier shrinkage andglacial lake growth
Suzuki (2004) estimated ablation on the debriscovered ablation areas of both the Thorthormi and Lugge
Glaciers through a heat budget calculation with meteorological data and surface temperatures captured from
ASTER infrared imagery. His target areas of the ablation
estimate included the longitudinal lines on both of theglaciers surveyed in this study. The results showed theablation ranging from 5 - 8 m a-1, depending on the debris
thickness, while the mean ablation was 6.8 and 6.9 m a-1
on the ablation areas of the Thorthormi and Lugge
Glaciers, respectively. In short, regarding the surface
mass balance averaged on the ablation areas of the twoneighboring debris-covered glaciers, no significant difference could be recognized. On the other hand, regarding the surface lowering and the flow speed, they appear
very contrastive, as mentioned above in subsections 3.1.1
and 3.1.2. This might be caused by the huge glacial lake,
Lugge Tsho. If a huge glacial lake exists in contact with aglacier, the lake water could accelerate the basal glacierflow of the terminal part through buoyancy and/or
lubrication effects. The terminal acceleration would
weaken the compressive flow and emergence velocity.
As a result, the surface lowering could be accelerated,because the weaker emergence velocity could cancel thesmaller portion of net ablation. This hypothesis can besupported with the present results on the Lugge Glacier,in contrast to those on the Thorthormi Glacier. Thismeans that a glacial lake could accelerate the thinning of
the upstream glacier, although existence of the glaciallake itself has been normally considered to be the resultof glacier shrinkage. Moreover, the glacier thinning
could activate calving by relatively enhancing the

Fig. 6 Longitudinal profile of the surveyed two ridges on theablation area of the Lugge Glacier, shown in Fig. 2. The
abscissa is the longitudinal distance relative to thelocation of the cross-point with the transversal survey
line of 2002, setting positive upstream. The thick dashedlines represent the linear regression of each year’s ridges,
the equations of which are also displayed.

Fig. 7 Longitudinal distribution of the horizontal surface flow
speed on the ablation area of the Lugge Glacier. The
abscissa is same as that in Fig. 6.

Fig. 8 Hypothetical illustration of a feedback mechanism
between glacier shrinkage and glacial lake growth, for
explaining contrastive features observed in surface
lowering and flow speed distribution between theablation areas of the Thorthormi and Lugge glaciers.

Recent Glacier Shrinkages in the Lunana Region, Bhutan Himalayas

buoyancy effect. After all, there might be a positive
feedback mechanism between glacier shrinkage andglacial lake growth, as illustrated in Fig. 8. The feedback
would work until glacier detached itself from the lake.
The initiation of the feedback might be related to the lake
depth versus glacier thickness, but this is still unclear andmakes further study desirable.
3.2 Debris-free glaciers
3.2.1 The Jichu Dramo Glacier
The surface topography of the lower part of the Jichu
Dramo Glacier is fairly wavy. Based on repeated topographical surveys conducted in 1998, 1999, 2003 and2010, the locations of surface bumps on the lower part of
the glacier are depicted in Fig. 9. Among the surface
bumps surveyed in 2010, six bumps were recognized tohave been surveyed before. These are indicated in Fig. 917

as solid symbols and their tentative names are given
without parentheses. From their horizontal displacements,
their horizontal velocities were calculated, as listed inTable 1. Generally, the horizontal speed decreases upstream to downstream, as usually seen in the ablation
area of a glacier. The change in the speed compared to theprevious result is not clear. The horizontal direction of
the velocity is almost northward at 16 cardinal points,
with the sole exception of the L2 bump moving to the
NNW.
The surveyed altitudes of the six bumps are then projected with respect to the northward distance relative to
the C1 bump location in 1998, as shown in Fig. 10. Thick
regression lines in Fig. 10 are obtained for the same fourbumps in 1999, 2003 and 2010. The regression line
lowered by 10.0 m upstream and 10.6 m downstream
between 1999 and 2003. The average surface lowering
rate was thus evaluated to be 2.6 m a-1 in 1999 - 2003.
Similarly, surface lowering was evaluated to be 22.7 m
upstream and 26.4 m downstream, the average rate ofwhich was 3.5 m a-1 in 2003 - 2010. If regression is used
for the bumps including C1 or C3’, the surface lowering
rates are evaluated to be a little different from theabove-mentioned ones. Considering the differences areless than 0.2 m a-1, the present result on the surface
lowering rate in 1999 - 2003 is consistent with the previous estimate of 2 - 3 m a-1 by Naito et al. (2006),
although they were estimated for different combinationsof bumps. Therefore, neglecting changes in the surface
undulation, the surface lowering rate in the lower part of
the Jichu Dramo Glacier is concluded to have been 3 4 m a-1 in 2003 - 2010, and it may have accelerated
compared to 1998 - 2003.
As a proglacial lake had been grown along the glacierterminus, the location of the glacier terminus could not be
surveyed in 2010. The terminal retreat since 2003,
unfortunately, could not be evaluated.

Fig. 9 Horizontal location of the surveyed surface bumps on thelower part of the Jichu Dramo Glacier. Solid symbols
indicate surface bumps surveyed more than twice. Theirtentative names are the same as those by Naito et al.
(2006), except for C3’. Bump names in parentheses
indicate bumps not surveyed in 2010. The six bumps
without parentheses are analyzed in the present study.
Table 1 Horizontal velocities of surveyed surface bumps on the
Jichu Dramo Glacier. The names of bumps are same as
those displayed in Fig. 9. The velocity is expressed ashorizontal speed U and azimuth from the north HA.
Name ofbump

The present results
U (m a-1)

HA (deg.)

periodThe previous results (Naito et al., 2006)
U (m a-1)

HA (deg.)

period

C1

19.1

2.0

1999 – 2010

24.0

342.5

1998 – 1999

C2

8.3

356.6

2003 – 2010

8.3

0.5

1999 – 2003

C3’

7.8

6.7

2003 – 2010

L1

7.6

1.5

2003 – 2010

9.0

355.0

1999 – 2003

L2

4.5

329.5

2003 – 2010

4.2

321.5

1999 – 2003

L3

8.8

351.5

2003 – 2010

6.2

353.9

1999 – 2003

(no survey before 2003)

Fig. 10 Vertical and northward projection of the six surface
bumps. The abscissa is the northward distance relative tolocation of bump C1 in 1998. The left side of the figure(southward) is upstream. The thick lines and equations
represent the linear regressions for the four bumps thatwere surveyed three times, in 1999, 2003 and 2010. The
thin ones are those for the five bumps including C1 and
C3’.

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N. NAITO et al.

3.2.2 A small unnamed glacier southeast of Jaze La
The surface topography of a small debris-free glaciersoutheast of Jaze La, designated number 1 in Fig. 3, wasalso surveyed in 1999 and 2010. Retreat and shrinkage ofthis small glacier can be easily confirmed at a glance, bycomparing the photographs in Fig. 11. The lines surveyed
in 2010 are superimposed on the contour map surveyed in
1999 in Fig. 12. The glacier terminus retreated by 46.4 m
averaged transversely during the eleven years, that is, it
had a retreating rate of 4.2 m a-1.
The glacier surface was quite smooth as seen in
Fig. 11, so that the surface altitude in 1999 at a point
along the surveyed line in 2010 could be interpolated
from two surveyed points nearby (“+” marks in Fig. 12)
in 1999. Using the interpolation, the surface lowering
was estimated at 7 points as shown in Fig. 12 with green“×” marks. As a result, the surface lowering was smaller
upstream and larger downstream. The annual rate wascalculated to be roughly 1 - 3 m a-1. On the other hand,the surveyed line in 2010 on the northern part of the ice
divide was located a few tens of meters westward fromthat in 1999. As this part of the ice divide was fairly wideand flat, the probable ridge top was surveyed both in1999 and 2010. Therefore, the surface lowering could be
estimated on this part, too, with a negligibly small error
from comparison of the surveyed altitudes in 1999 to theeast and in 2010 to the west. The estimated results at foursites are shown with green arrows in Fig. 12. These
results agree with the above-mentioned features of the
distribution and range of the annual rates.
3.2.3 Glacier shrinkage confirmed from repeatedphotosTerminal retreats and/or thinning of four otherdebris-free glaciers, numbered 2 - 5 in Fig. 3, can berecognized by comparing more recent photographs withprevious ones, as shown in Figs. 13 - 16, respectively.
One glacier, designated number 2, has significantly
thinned on the left side and its terminal retreat is clear on
the right side in Fig. 13. In fact, the surveyed small unnamed glacier mentioned in the preceding subsection
3.2.2 is located in the opposite valley beyond the left colof a peak seen in the right half of the photo in Fig. 13. A
second glacier, designated number 3, can be clearlyrecognized in Fig. 14 to have retreated and thinned in
1999 - 2009. A third glacier, number 4, retreated drastically and its proglacial lake expanded in 1984 - 1999, asshown in Fig. 15, as previously reported by Naito et al.
(2006). This glacier has continued to retreat and shrink in
the 21st century, but its rate seems to have become relatively moderate. Its terminus may detach from the proglacial lake in the near future. A fourth glacier, number 5,
has shrunk, too, as seen in Fig. 16. The glacier tongue
part on the right side has disappeared and the left part has
thinned in Fig. 16.
It would be highly desirable to develop and makepracticable a convenient and precise method of photogrammetry for such remote glaciated fields in the future,in order to measure such glacier shrinkages easily.

Fig. 11 Repeated photos of the small unnamed glacier southeastof Jaze La, designated number 1 in Fig. 3, taken from thebase point in Fig. 12. The shot dates are Oct. 2, 1999 and
Sep. 23, 2010.

Fig. 12 Surveyed lines for the small unnamed glacier southeast of
Jaze La, designated number 1 in Fig. 3; on the glacier (reddashed), terminus (red solid) and shoreline of the
proglacial pond (blue). The background contour map was
surveyed in 1999 (Naito et al., 2006). The altitude of thebase point was revealed to be 5,269 m a.s.l. by static GPS
measurement in 2010. The green values are the reduction
in altitude (m) between 1999 and 2010 evaluated in thepresent study, while the accuracy of that in parentheses at
the terminus is low due to bad conditions for receiving
GPS signals.

Recent Glacier Shrinkages in the Lunana Region, Bhutan Himalayas

1984

2010
Fig. 13 Repeated photos of glacier number 2 in Fig. 3, taken from Jaze La. The shot dates are Oct. 8, 1984
(provided by Dr. Toshihiro Tsukihara) and Oct. 1, 2010.

1999

2009
Fig. 14 Repeated photos of glacier number 3 in Fig. 3. The shot dates are Sep. 30, 1999 and Sep. 24, 2009.

19

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N. NAITO et al.

Fig. 15 Repeated photos of glacier number 4 in Fig. 3, taken from Gangrinchemzoe
La. The shot dates are Oct. 2, 1984 (provided by Dr. Toshihiro Tsukihara),
Oct. 9, 1999 and Oct. 5, 2010.

Fig. 16 Repeated photos of glacier number 5 in Fig. 3. The shot dates are Oct. 13,
1998 and Oct. 5, 2010.

Recent Glacier Shrinkages in the Lunana Region, Bhutan Himalayas

4. Concluding Remarks
The present paper evaluated surface lowering rates onfour glaciers in Bhutan and found 0 - 3 m a-1 on theablation area of the Thorthormi Glacier in 2002 - 2004,
approximately 5 m a-1 on the ablation area of the Lugge
Glacier in 2002 - 2004, 3 - 4 m a-1 on the lower part of the
Jichu Dramo Glacier in 2003 - 2010, and 1 - 3 m a-1 on
the small unnamed glacier southeast of Jaze La in 1999 2010. These results are valuable because information
related to volumetric shrinkage of glaciers in Bhutan has
been limited so far.
Contrastive results in the surface lowering and distribution of flow speed between the two debris-covered
glaciers, the Thorthormi and Lugge Glaciers, have suggested a positive feedback mechanism between glaciershrinkage and glacial lake growth. It would be desirable
to study this further in order to understand the expansion
process of glacial lakes as well as the fluctuation mechanism of calving glaciers.
The surface lowering rate of the Jichu Dramo Glacierin 2003 - 2010 seems to have accelerated from the previous estimate of 2 - 3 m a-1 in 1998 - 2003 (Naito et al.,2006). Such acceleration of glacier shrinkage should be
carefully monitored to confirm it.
Repeated photographs have been accumulated toshow glacier shrinkage and retreat in Bhutan, several
representative pairs of which are provided in the present
paper. It would be advisable to develop and apply apractical photogrammetry in order to accumulate quantitative information on glacier shrinkage and retreat in the
future.

Acknowledgements
We are deeply indebted to staff of the Department of
Geology and Mines (DGM), Ministry of Economic
Affairs, Bhutan, for their consideration and support for
our field research activities. We thank all members who
participated in field activities related to the present study
for their assistance. We would like to express special
gratitude to Dr. Koji Fujita for GPS post-processing, Dr.
Takeo Tadono for providing ALOS AVNIR-2 images,
and Dr. Toshihiro Tsukihara for providing the glacierphotos taken in the 1980s. The manuscript was improvedby useful comments from Prof. Teiji Watanabe and an
anonymous reviewer. The field activities in 2002 - 2004
were financially supported by Grants-in-Aid for Scientific Research (Nos. 13373006 and 13573004) from theJapan Society for the Promotion of Science (JSPS). The
field activities in 2010 were supported by the Japan
Science and Technology Agency (JST) and the Japan
International Cooperation Agency (JICA), under the
Science and Technology Research Partnership for
Sustainable Development (SATREPS). The data analysis
in this paper was supported by a Grant-in-Aid for Scientific Research (No. 20540430) from JSPS. In addition,
the present study has been motivated and encouraged fora relatively long time, especially by Profs. Yutaka Ageta,

21

Shuji Iwata, Tomomi Yamada and Kouichi Nishimura, towhom we would like to express our sincere thanks. At
last, we would like to express our sincere condolences on
the death of Mr. Dorji Wangda, the former Director of
DGM. Our research activities in Bhutan since 1998
would never have been accomplished without his
considerations and efforts.
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Suzuki, R. (2004) Estimation on Glacier Melting in Lunana
Region, Bhutan. Master thesis, Nagoya University. (in Japanesewith English abstract)
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Tomiyama and H. Yabuki (2012) Development and validation of
new glacial lake inventory in the Bhutan Himalayas using ALOS‘DAICHI.’ Global Environmental Research, 16: 31-40.
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Nepal Himalayas. Monograph No. 1, Data Center for GlacierResearch, Japanese Society of Snow and Ice.

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N. NAITO et al.
Nozomu NAITO

Nozomu NAITO is a Professor at the Hiroshima
Institute of Technology. He has investigatedglacier variations in the Himalayas since 1995,
when he started his PhD course study at Nagoya
University. He obtained his PhD in 2001, with afocus on numerical studies on recent glaciershrinkages in the Nepal Himalayas. He has joined field research teams
studying glaciers and glacial lakes in Bhutan four times so far, in 1998,
1999, 2002 and 2010. Recently, his growing interest in the interaction
between glacier shrinkage and glacial lake expansion in the Himalayas has
led him to expand his scope to the flow and variations of calving glaciers in
Patagonia, too. He was a member of the 34th Japanese Antarctic Research
Expedition in 1992-1994. In addition to his research activities, he now
works in education and providing support for diversifying students.

Ryohei SUZUKI
Ryohei SUZUKI obtained his PhD in sciencefrom Nagoya University, Japan in 2007. His
primary interest is in spatial distributions ofthermal properties of debris cover on glaciers inthe Himalayas, focusing on the relationship ofsuch thermal properties to the ice melt rates
under the debris covers, using a heat budget approach. He is also interested
in applying image analysis techniques using optical and thermal remotesensing data and digital elevation modelling to glaciological studies. He
joined field research teams studying glaciers and glacial lakes in Bhutan
three times in 2002-2004. In addition, he participated in glaciological fieldresearch in Patagonia in 2004 and 2005. He is now engaging in the field ofsoftware engineering with Fujitsu Software Technologies Co., Ltd., taking
a special interest in applications of image processing and computer
graphics techniques.

Jiro KOMORIJiro KOMORI is a JICA expert on technical/
research cooperation in Bhutan, and holds anappointment as a Contract Assistant Professor at
the Graduate School of Environmental Studies,
Nagoya University. As a JICA expert, he has
been dispatched to the newly established
Division of Glaciology at the Department of Geology and Mines, Royal
Government of Bhutan since 2009. Originally he worked for four years as
an engineer at a geological consulting company and subsequently for four
years at Nihon University as a laboratory assistant until 2000. He obtained
his PhD in paleoenvironmental studies from the Graduate School of Tokyo
Metropolitan University in 2005. As a graduate student, he also started to
study subjects such as disaster prevention related to recent environmental
change. His first field survey of glaciers and glacial lakes was in the
Bhutan Himalayas in 2002. This brought an opportunity for precious
experience and many encounters in Bhutan to not only himself but also his
family. He currently has a keen interest and is seeking ways to disseminate
the results of this research and educate the younger generation regarding
the issues of environmental change rather than interest in the naturalsciences.

Yoshihiro MATSUDA
Yoshihiro MATSUDA’s main interest has been inglacier variations and the glacier surface energybalance in the Asian Highlands since 2001, when
he entered the Graduate School of Environmental Studies, Nagoya University. He obtained
his PhD from Nagoya University in 2008
through his research on numerical studies of climatic sensitivity of glaciersin the Asian Highlands. He has joined several glacier research teams in the
Asian Highlands, and he participated field research teams on glaciers andglacial lakes in Bhutan in 2003 and 2004.

Satoru YAMAGUCHI
Satoru YAMAGUCHI is a researcher at the Snowand Ice Research Center, National ResearchInstitute for Earth Science and Disaster Prevention. His present subjects of interest are snow
physics and development of a snow cover model
to forecast snow disasters, such as snow avalanches, snow drifts and so on. In addition, he has maintained a strong
interest in glacier variations in the Himalaya region because his first glaciersurvey was in the Nepal Himalayas in 1995 and the theme of his doctoral
thesis was glacier dynamics. Nowadays, using glacier fluctuation models,
he is investigating the mechanisms of debris-covered glacier development:
the critical conditions distinguishing clean-type glaciers from debriscovered glaciers, and what factors determine the surface inclination ofdebris-covered glaciers.

Takanobu SAWAGAKI
Takanobu SAWAGAKI is an Assistant Professor of
the Faculty of Environmental Earth Science,
Hokkaido University. His major fields of study
are Glacial Geology, Quaternary Science andGeographical Information Systems. He has broad
experience in circumpolar and alpine regions as amember of Japanese Antarctic research expeditions, the Academic Alpine
Club of Hokkaido, and his own research expeditions in cold regions aroundthe world.

Phuntsho TSHERING
Phuntsho TSHERING is a geologist working in the
Department of Geology and Mines, Ministry of
Economic Affairs, Royal Government of Bhutan.
He did his undergraduate work in the fields ofMathematics, Physics and Geology at the Post
Graduate College of Science, Osmania University, India. One year after joining the department in 2008, he started
working in the Glaciology Division and since then, he has been an active
counterpart for a collaborative research project involving his department,
JICA and JST. Working together with the JICA experts, he has been
actively involved in implementing field activities along the northern
glaciated frontiers of Bhutan in 2009, 2010 and 2011. Having been
involved in such activities, he has a keen interest in specializing in thefields of environmental sciences and global climate change and its
associated risks.

Kharka Singh GHALLEY
Kharka Singh GHALLEY is currently working as a
Senior Geologist in the Glaciology Division,
Department of Geology and Mines, Ministry of
Economic Affairs, Royal Government of Bhutan.
He earned his diploma in Mineral Exploration(Geology) from 1978 to 1980. He started his
career in systematic geological mapping, mineral exploration, investigation of economic minerals and conducting expeditions in the higher Bhutan
Himalayas. He attended the short-term training course on GeophysicalSurveying for Ground Water Exploration at the National GeophysicalResearch Institute, Hyderabad, India in 1987. He undertook the 15th
Post-Graduate Orientation Training Course organized by the Geological
Survey of India at various training institutes/centers in 1990-1991 andcompleted the course with excellent marks. Since the establishment of thecollaborative research project between DGM-JICA/JST he has been one of
the active participants as a Bhutanese counterpart in the research project.
He is closely associated with JICA short/long term experts; he has been
constantly involved in implementing ground data collection works at the
headwaters of the major river basins in the northern glaciated frontier
region of the Bhutan Himalayas.

(Received 30 November 2011, Accepted 13 February 2012)