COSMO-SkyMed SAR 영상을 이용한 동남극 Campbell 빙하의 연간 면적변화 및 유속 추정

한향선 ( Hyang Sun Han ),지영훈 ( Young Hun Ji ),이훈열 ( Hoon Yol Lee ) 대한원격탐사학회 2013 大韓遠隔探査學會誌 Vol.29 No.1

동남극의 Campbell 빙하는 테라노바 만으로 유출되는 주요한 빙하 중 하나이다. Campbell 빙하는 동남극 빙상의 질량 균형에 영향을 미치고 있기 때문에 정확한 면적 및 흐름속도의 분석이 필요하다. 그러나 Campbell 빙하에 대한 연구는 1990년 이후로 거의 수행되지 않았다. 이 연구에서는 2010년 6월부터 2012년 1월 사이에 Campbell 빙하가 촬영된 59장의 COSMO-SkyMed SAR 영상을 획득하였다. 디지타이징 방법과 영상정합에 의한 변위추적 기법을 적용하여 Campbell Glacier Tongue의 면적과 Campbell 빙하의 흐름속도를 추정하였다. Campbell Glacier Tongue의 면적은 여름철에 얼음의 붕괴로 인해 감소하고 겨울철에 증가하지만 증감의 폭이 크지 않았고, 평균 75.5 km2의 면적을 유지하였다. Campbell Glacier Tongue의 유출량은 0.58±0.12 km3/yr로 추정되었는데, 이는 1989년에 비해 증가한 것이다. Campbell Glacier Tongue의 흐름속도는 181-268 m/yr로서 1988-1989년의 흐름속도에 비해 빠르며, 이는 빙하의 유출량 증가에 영향을 준 것으로 해석되었다. Campbell Glacier in East Antarctica is one of the major glaciers that flow into Terra Nova Bay. It is necessary to estimate accurate extent and flow velocity of Campbell Glacier which influences the dynamics of mass balance of East Antarctic Ice Sheet. However, few studies on Campbell Glacier have been performed since 1990s. In this study, we obtained a total of 59 COSMOSkyMed SAR images over Campbell Glacier from June 2010 to January 2012. We estimated variations in the extent of Campbell Glacier Tongue and flow velocity of Campbell Glacier by applying the image digitizing and the offset tracking by image matching. Although the extent of Campbell Glacier Tongue decreased in summertime due to ice calving and increased in wintertime, the variation in the extent was very small. Campbell Glacier Tongue retained mean extent of 75.5 km2. The ice discharge of Campbell Glacier Tongue was estimated to be 0.58±0.12 km3/yr, which was bigger than in 1989. The flow velocity over Campbell Glacier Tongue was estimated to be from 181 to 268 m/yr that was faster than in 1988-1989, which contributed to the increase in the ice discharge of the glacier.

KOMPSAT-5 위성영상의 Coarse-to-fine SAR 오프셋트래킹 기법을 활용한 동남극 Campbell Glacier의 2차원 이동속도 관측

채성호 ( Sung-ho Chae ),이광재 ( Kwang-jae Lee ),이선구 ( Sungu Lee ) 대한원격탐사학회 2021 大韓遠隔探査學會誌 Vol.37 No.6

빙하 이동속도는 빙하역학 연구에 가장 기초가 되는 관측치로 기후 변화에 따른 해수면 상승 등을 예측하는데 매우 중요한 지시자이다. 본 연구에서는 SAR 오프셋트래킹 기법을 통해 동남극 테라노바 만에 위치한 Campbell Glacier에 대한 2차원 이동속도를 관측하였다. 이를 위하여 연구지역에 대하여 2021년 7월 9일과 2021년 8월 6일에 촬영한 국내 KOMPSAT-5 SAR 위성영상을 획득하였다. 선행 연구를 통하여 제안한 다중변위커널을 활용한 오프셋트래킹 기법은 해상도와 정밀도를 모두 만족하는 최적의 결과를 얻는 기법이다. 하지만 커널 크기에 따라 오프셋트래킹을 반복하여 수행하기 때문에 매우 집약적인 연산 능력과 시간이 필요하게 된다. 따라서 본 연구에서는 전략적으로 coarse-to-fine SAR 오프셋트래킹 방법을 고안하였다. coarse-to-fine 오프셋트래킹을 통하여 일반적인 오프셋트래킹 결과보다 해상도는 유지되고 정밀도는 향상(특히, 비행방향으로 약 4배)된 결과를 획득할 수 있다. 이 기법을 활용하여 Campbell Glacier에 대한 2차원 이동속도 영상을 생성하였다. 2차원 이동속도 영상을 분석한 결과 Campbell Glacier의 지반선(grounding line)은 대략 위도 -74.56N 부근에 존재하는 것으로 관측할 수 있었다. 이 연구에서 분석된 Campbell Glacier Tongue의 흐름속도(185-237 m/yr)는 1988-1989년의 흐름속도(140-240 m/yr)에 비하여 증가하였다. 그리고 2010-2012년의 흐름속도(181-268 m/yr)에 비하여 지반선 부근에서 이동속도는 유사하였지만 Campbell Glacier Tongue의 끝부분에서의 이동속도는 감소한 것을 확인할 수 있었다. 하지만 이는 본 연구의 연구 결과는 28일 동안 발생한 빙하의 이동속도를 연간 속도로 환산한 것이기 때문에 발생하는 오차일 가능성이 있다. 향후 정확한 비교를 위해서는 시계열적으로 자료를 확장하여 연간 속도를 정확하게 계산하는 과정이 필요할 것이다. 이 연구를 통해 최초로 국내 X-밴드 SAR 위성인 KOMPSAT-5 위성 영상을 활용하여 빙하의 2차원 이동속도를 관측하였으며, KOMPSAT-5 영상의 coarse-to-fine SAR 오프셋트래킹 기법이 빙하의 2차원 이동속도 관측에 매우 유용함을 확인할 수 있었다. Glacier movement speed is the most basic measurement for glacial dynamics research and is a very important indicator in predicting sea level rise due to climate change. In this study, the two-dimensional velocity measurements of Campbell Glacier located in Terra Nova Bay in East Antarctica were observed through the SAR offset tracking technique. For this purpose, domestic KOMPSAT-5 SAR satellite images taken on July 9, 2021 and August 6, 2021 were acquired. The Multi-kernel SAR offset tracking proposed through previous studies is a technique to obtain the optimal result that satisfies both resolution and precision. However, since offset tracking is repeatedly performed according to the size of the kernel, intensive computational power and time are required. Therefore, in this study, we strategically proposed a coarse-to-fine offset tracking approach. Through coarse-to-fine SAR offset tracking, it is possible to obtain a result with improved observation precision (especially, about 4 times in azimuth direction) while maintaining resolution compared to general offset tracking results. Using this proposed technique, a two-dimensional velocity measurements of Campbell Glacier were generated. As a result of analyzing the two-dimensional movement velocity image, it was observed that the grounding line of Campbell Glacier exists at approximately latitude -74.56N. The flow velocity of Campbell Glacier Tongue analyzed in this study (185-237 m/yr) increased compared to that of 1988-1989 (140-240 m/yr). And compared to the flow velocity (181-268 m/yr) in 2010-2012, the movement speed near the ground line was similar, but it was confirmed that the movement speed at the end of the Campbell Glacier Tongue decreased. However, there is a possibility that this is an error that occurs because the study result of this study is an annual rate of glacier movement that occurred for 28 days. For accurate comparison, it will be necessary to expand the data in time series and accurately calculate the annual rate. Through this study, the two-dimensional velocity measurements of the glacier were observed for the first time using the KOMPSAT-5 satellite image, a domestic X-band SAR satellite. It was confirmed that the coarse-to-fine SAR offset tracking approach of the KOMPSAT-5 SAR image is very useful for observing the two-dimensional velocity of glacier movements.

Flow Trends in River Chitral due to Different Scenarios of Glaciated Extent

Usman Ali Naeem,Hashim Nisar Hashmi,Habib-ur-Rehman,Abdul Sattar Shakir 대한토목학회 2013 KSCE JOURNAL OF CIVIL ENGINEERING Vol.17 No.1

Glaciers are considerably important machinery which is necessary to keep the equilibrium of the earth. The rapid boost in the mean temperatures of the globe and abnormal precipitations are the direct warnings for glaciers to survive. Mostly the perennial rivers of the world emerge from glaciers. In an agricultural country like Pakistan the existence of the glaciers is of prime importance. The major river of the country originates from the Himalayan and Karakorum glaciated mountains. River Indus is a vital example. Moreover the mega and world renowned Tarbela dam also exists on the same river. This can be surly concluded that the future of a country is directly associated with the flows available in the rivers and hence the existence of glaciers. The rapid disintegration of the glaciers has been reported throughout the world which is obviously not a healthy sign. Therefore, a careful study is required to estimate the variations of the flows with the receding glaciers. As a case study, Chitral watershed in Pakistan has been selected. The UBC watershed model has been used to forecast the flows. The model was calibrated for the daily flows observed in 2009 at Chitral stream gauging station. The percentage contributions to the total annual flow were simulated as 23%, 31%, 1% and 45% due to glacier melt, snow melt, rain-fall runoff and groundwater, respectively for year 2009. Model results were validated for the flows of year 2006 and 2007. The further analysis was performed by assuming reduction in glaciated areas and considering the climatological conditions same as observed in year 2009. The model results show that a significant decrease in the flows of Chitral River appears due to the assumed reduction of glaciated extent.

Soil development and bacterial community shifts along the chronosequence of the Midtre Lovénbreen glacier foreland in Svalbard

Kwon, Hye Young,Jung, Ji Young,Kim, Ok-Sun,Laffly, Dominique,Lim, Hyoun Soo,Lee, Yoo Kyung The Ecological Society of Korea 2015 Journal of Ecology and Environment Vol.38 No.4

Global warming has accelerated glacial retreat in the high Arctic. The exposed glacier foreland is an ideal place to study chronosequential changes in ecosystems. Although vegetation succession in the glacier forelands has been studied intensively, little is known about the microbial community structure in these environments. Therefore, this study focused on how glacial retreat influences the bacterial community structure and its relationship with soil properties. This study was conducted in the foreland of the Midtre Lovénbreen glacier in Svalbard (78.9°N). Seven soil samples of different ages were collected and analyzed for moisture content, pH, soil organic carbon and total nitrogen contents, and soil organic matter fractionation. In addition, the structure of the bacterial community was determined via pyrosequencing analysis of 16S rRNA genes. The physical and chemical properties of soil varied significantly along the distance from the glacier; with increasing distance, more amounts of clay and soil organic carbon contents were observed. In addition, Cyanobacteria, Firmicutes, and Actinobacteria were dominant in soil samples taken close to the glacier, whereas Acidobacteria were abundant further away from the glacier. Diversity indices indicated that the bacterial community changed from homogeneous to heterogeneous structure along the glacier chronosequence/distance from the glacier. Although the bacterial community structure differed on basis of the presence or absence of plants, the soil properties varied depending on soil age. These findings suggest that bacterial succession occurs over time in glacier forelands but on a timescale that is different from that of soil development.

Soil development and bacterial community shifts along the chronosequence of the Midtre Lovénbreen glacier foreland in Svalbard

권혜영,Ji Young Jung,김옥선,Dominique Laffly,임현수,이유경 한국생태학회 2015 Journal of Ecology and Environment Vol.38 No.4

Global warming has accelerated glacial retreat in the high Arctic. The exposed glacier foreland is an ideal place to study chronosequential changes in ecosystems. Although vegetation succession in the glacier forelands has been studied intensively, little is known about the microbial community structure in these environments. Therefore, this study focused on how glacial retreat influences the bacterial community structure and its relationship with soil properties. This study was conducted in the foreland of the Midtre Lovénbreen glacier in Svalbard (78.9°N). Seven soil samples of different ages were collected and analyzed for moisture content, pH, soil organic carbon and total nitrogen contents, and soil organic matter fractionation. In addition, the structure of the bacterial community was determined via pyrosequencing analysis of 16S rRNA genes. The physical and chemical properties of soil varied significantly along the distance from the glacier; with increasing distance, more amounts of clay and soil organic carbon contents were observed. In addition, Cyanobacteria, Firmicutes, and Actinobacteria were dominant in soil samples taken close to the glacier, whereas Acidobacteria were abundant further away from the glacier. Diversity indices indicated that the bacterial community changed from homogeneous to heterogeneous structure along the glacier chronosequence/distance from the glacier. Although the bacterial community structure differed on basis of the presence or absence of plants, the soil properties varied depending on soil age. These findings suggest that bacterial succession occurs over time in glacier forelands but on a timescale that is different from that of soil development.

A report on tectonically sculptured unique glacier landform: a case study from the Tethys Kumaun Himalaya, India

Manish Mehta,Rahul Devrani,Khayingshing Luirei,Vinit Kumar 한국지질과학협의회 2022 Geosciences Journal Vol.26 No.2

In the present study, we are reporting an unnamed glacier located (30.28089N- 80.69344E) in the upper Kali Ganga valley, Pithoragarh district, Uttarakhand, India, which has been affected by active fault and climate change. Recent tectonic activity and change in climatic conditions have changed the course and morphology of this glacier. An active fault has produced a fault scarp that measures about 250 m in height with a northerly dip, the fault trace is 6.2 km in length and trend towards NW-SE. The observation is based on the satellite image, toposheet and Google Earth images. We observed that the 5 km long unnamed glacier, which covered ~4 km2 area in Kuthi Yankti valley (Tributary of Kali River) has abruptly changed its main course. The NE moving glacier has been abruptly truncated and forced to move towards SE and ultimately merges with the adjacent glacier named Sumzurkchanki as a result of tectonic forcing. It is one of the unique behaviors of the glacier, which is for the first time reported from the Himalayan glacier as no such observation have so far been reported on this type of glacier kinematics. The study will help to understand the glacial-tectonic interaction and provides key information for future studies.

TerraSAR-X 위성레이더 오프셋 트래킹 기법을 활용한 스발바르 Uvêrsbreen 빙하의 2차원 속도 관측

백원경 ( Won-kyung Baek ),정형섭 ( Hyung-sup Jung ),채성호 ( Sung-ho Chae ),이원진 ( Won-jin Lee ) 대한원격탐사학회 2018 大韓遠隔探査學會誌 Vol.34 No.3

Global interest in climate change and sea level rise has led to active research on the velocities of glaciers. In studies about the velocity of glaciers, in-situ measurements can obtain the most accurate data but have limitations to acquire periodical or long-term data. Offset tracking using SAR is actively being used as an alternative of in-situ measurements. Offset tracking has a limitation in that the accuracy of observation is lower than that of other observational techniques, but it has been improved by recent studies. Recent studies in the Uvêrsbreen glacier area have shown that glacier altitudes decrease at a rate of 1.5 m/year. The glacier displacement velocities in this region are heavily influenced by climate change and can be important in monitoring and forecasting long-term climate change. However, there are few concrete examples of research in this area. In this study, we applied the improved offset tracking method to observe the two-dimensional velocity in the Uvêrsbreen glacier. As a result, it was confirmed that the glacier moved at a maximum rate of 133.7 m/year. The measruement precisions for azimuth and line-of-sight directions were 5.4 and 3.3 m/year respectively. These results will be utilized to study longterm changes in elevation of glaciers and to study environmental impacts due to climate change.

Estimating thickness of Zemu glacier, Sikkim (India) using ice-flow velocity approach: a geoinformatics based perspective

Shubham Bhattacharjee,Arvind Chandra Pandey 대한공간정보학회 2023 Spatial Information Research Vol.31 No.5

In the present scenario of warming climate, overall health of the glaciers along with sea level rise/fall are directly impacted by glacial dynamics. However due to inaccessible high altitude regions and devastating climate, the in-situ observations are hindered via field excursions. The present study incorporated usability of geographical information system based ice-flow velocity approach using glacier surface velocity and slope for estimating thickness of Zemu glacier in Sikkim. The study revealed thickness of 80 ± 9.6 m to 160 ± 19.2 m near snout followed by 240 ± 28.8 m to 320 ± 38.4 m in upper reaches of accumulation zone of Zemu glacier. However due to gentle slope, thickness ranged between 320 ± 38.4 m and > 400 ± 49.2 m (~ 418 ± 50.16 m) was observed in the central trunk or middle reaches of the glacier. An uncertainty of 12% was observed while calculation the glacier thickness. Relationship between glacier velocity and depth has also been established which has shown inverse characteristics due to variability of bed topography and drag effects. Proper validation of results for each study with existing field observations and literatures depicted the utility and correctness of the present study via satellite based observations.

백두산 빙하지형의 존재 가능성과 제4기 화산활동과의 관계

이성이(Sungee Lee),성영배(Yeong Bae Seong),강희철(Hee-Cheol Kang),최광희(Kwang Hee Choi) 대한지리학회 2012 대한지리학회지 Vol.47 No.2

백두산의 현재 지형은 반복적인 화산활동과 함께 신생대 제4기 기후변화로 추동된 빙하 활동의 결과물이다. 그러나 여전히 백두산 빙하지형의 존재에 대한 의문들은 해소되지 못해왔다. 이에, 본 연구에서는 야외조사를 통하여, 빙하지형에 관련된 지형들을 제시하고, 이의 연대측정을 실시하였으며, 제4기 화산 활동과의 관련성을 살펴보았다. 가속기 질량 분석기를 이용하여 빙하의 후퇴 이후 지표면에 노출되었을 백두산 천지 서사면의 빙하 기반암 지형 면에 대하여, 우주선 유발 동위원소 36Cl의 농도를 측정하여 46~26ka의 표면노출연대를 얻었으며, 이는 적어도 천지 서쪽 사면은 지난 최종빙기 이후의 화산활동에 영향을 받지 않은 것을 지시하며, 특히 대략 천 년 전에 있었다고 보고되는 폭발성 분화에도 영향을 거의 받지 않았을 가능성이 매우 높다. 또한, 화산 쇄설물의 비대칭적 퇴적을 고려했을 때, 계절적으로 이 분화는 북서풍이 탁월한 겨울철에 발생한 것으로 사료된다. 빙하지형과 이의 연대 결과를 바탕으로 지형 발달과정을 복원해보면, 백두산의 빙하 지형은 지난 빙기까지 곡빙하(valley glacier)들이 연합한 빙모(ice cap) 형태에서 고립된 곡빙하를 거쳐 화산체 내부의 소규모 권곡(cirque) 형태로 변화한 것으로 추론된다. Since the suggestions on the paleo-glacial landforms in and around the northern high mountains of Korean Peninsula by some western and Japanese scientists in the early 1900s, the likelihood of the glacier existence in the Baekdusan over the Quaternary glacial period has been had in common among most of the Korean geomorphologists. In the other meaning, some have cast doubt on the likelihood the paleoglacier in the Baekdusan because there has been no unequivocal evidences for the glacier such as striation, moraines, except morphologic characteristic landforms possibly related to glacier. Here we show some evidences for the existence of the glacier in the Baekdusan and their cosmogenic 36Cl exposure ages over the late Quaternary and would put forward a model on the Quaternary landscape evolution of the Baekdusan, with a focus on the relationship of 1000 AD explosive eruption and the glacial landforms. The exposure ages constrained by cosmogenic 36Cl abundances of the col surface of the western slope located below the glacier yield 46~26 ka, which is inphase with the last glacial period. Given all the evidences above, we can draw a conclusion that the glacier existed on the Baekdusan over the late Quaternary and the style of glaciation changed from extensive ice cap through valley glacier to restricted cirque.

하계 마리안 소만 빙하후퇴에 따른 식물플랑크톤 변동성 분석

심초롬,민준오,이보연,홍서연,하선용 해양환경안전학회 2023 해양환경안전학회지 Vol.29 No.5

Rapid climate change has resulted in glacial retreat and increased meltwater inputs in the Antarctic Peninsula, including King George Island where Marian Cove is located. Consequently, these phenomena are expected to induce changes in the water column light properties, which in turn will affect phytoplankton communities. To comprehend the effects of glacial retreat on the marine ecosystem in Marian Cove, we investigated on phytoplankton biomass (chlorophyll-a, chl-a) and various environment parameters in this area in December 2021 and January 2022. The average temperature at the euphotic depth in January 2022 (1.41 ± 0.13 ℃) was higher than that in December 2021 (0.87 ± 0.17 ℃). Contrastingly, the average salinity was lower in January 2022 (33.9 ± 0.10 psu) than in December 2021 (34.1 ± 0.12 psu). Major nutrients, including dissolved inorganic nitrogen, phosphate, and silicate, were sufficiently high, and thus, did not act as limiting factors for phytoplankton biomass. In December 2021 and January 2022, the mean chl-a concentrations were 1.03 ± 0.64 and 0.66 ± 0.15μg L-1, respectively. The mean concentration of suspended particulate matter (SPM) was 24.9 ± 3.54 mg L-1 during the study period, with elevated values observed in the vicinity of the inner glacier. However, relative lower chl-a concentrations were observed near the inner glacier, possibly due to high SPM load from the glacier, resulting in reduced light attenuation by SPM shading. Furthermore, the proportion of nanophytoplankton exceeded 70% in the inner cove, contributing to elevated mean fractions of nanophytoplankton in the glacier retreat marine ecosystem. Overall, our study indicated that freshwater and SPM inputs from glacial meltwater may possibly act as main factors controlling the dynamics of phytoplankton communities in glacier retreat areas. The findings may also serve as fundamental data for better understanding the carbon cycle in Marian Cove. 세종기지가 위치한 마리안 소만은 기후 변화로 인한 빙하후퇴로 다량의 융빙수가 유입되고 있다. 이러한 빙하후퇴에 따른 생태계 반응을 예측하기 위해, 해양 환경 변화의 지시자인 식물플랑크톤 생체량 및 크기 구조와 물리, 화학적 매개변수에 대한 현장 조사를 2021년 12월, 2022년 1월 두 차례 수행하였다. 2022년 1월의 수온과 염분은 평균 1.41 ± 0.13 ℃, 33.9 ± 0.10 psu로 2021년 1월의 수온과 염분인 0.87 ± 0.17 ℃, 34.1 ± 0.12 psu보다 상대적으로 고온, 저염의 양상을 보였다. 조사시기 동안 영양염류는 대체로 높은 농도를 보여 식물플랑크톤의 제한요소로 작용하지 않은 것으로 판단된다. 식물플랑크톤 생체량의 지표인 엽록소는 2021년 12월, 2022년 1월에 각각 1.03 ± 0.64 μg L-1, 0.66 ± 0.15 μg L-1로 나타났으며 부유물질은 전체 조사기간 평균 24.9 ± 3.54 mg L-1로 나타났다. 부유물질의 농도가 높은 소만 내측에서 엽록소는 낮은 농도를 보였는데 이는 융빙수로부터 유입되는 고농도의 부유물질로 인해 수층 내 빛이 강하게 제한되어 식물플랑크톤의 성장이 저해된 것으로 판단된다. 또한, 빙벽 주변 정점에서 크기가 작은 미소 식물플랑크톤이 전체 식물플랑크톤 생체량에서 70% 이상 차지하는 것으로 나타났으며 이는 융빙수 유입으로 유발된 저조도 환경에서 미소 식물플랑크톤의 기여도가 증가할 수 있음을 시사한다. 따라서 본 연구는 빙하후퇴 지역에서 유입되는 담수와 부유물질이 식물플랑크톤의 생체량 및 군집구조 조절 요인이 될 수 있음을 시사하며, 결과 자료는 추후 마리안 소만의 탄소순환 변동을 파악하는 기초자료로 활용될 수 있다.