• Title/Summary/Keyword: retreat

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Ice cliff retreat and sea-ice formation observed around King Sejong Station in King George Island, West Antarctica (세종기지 주변에서 관찰된 빙벽 후퇴와 바다 결빙)

  • Chung, Ho-Sung;Lee, Bang-Yong;Chang, Soon-Keun;Kim, Ji-Hee;Kim, Yea-Dong
    • Ocean and Polar Research
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    • v.26 no.1
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    • pp.1-10
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    • 2004
  • Ice cliff retreat and sea-ice formation around King Sejong Station in King George Island were analysed and compared with air temperature change. Analysis of 33-year (1969-2001) air temperature records at Bellingshausen Station has revealed regional atmospheric warming, and the increasing rate of air temperature Is equivalent to a warming of $1^{\circ}C$ for 27-year period. Here we present time-series of observations for the areal extent of the ice cliff and ice sheet, showing that they have retreated dramatically in the past 45 years (1956-2001). Retreat of 1,050 m in length of the ice clifr has changed the Marian Cove into a low rectangular form of 4 km in length and 1 to 1.3km in width. The retreat rates have since increased from 6 m/yr of the Primary investigated Period to 54 and 81m/yr in the recent years. Exceptionally, the ice cliff had been advanced of 21m in length for a year between 1987 and 1988 of cold winters. Ice sheet in King George Island also shows a similar decrease, and the decreasing extent is much larger at the southern part of the Main Cove, relatively more exposed to the sun, than at the northern part. Comparing sea-ice formation in winter with air temperature data shows a pattern starting to freeze below $-5^{\circ}C$ and to thaw over $-3^{\circ}C$. It is conclusively estimated that the patterns and magnitudes of ice cliff retreat and sea-ice formation are consistent with fluctuations of the air temperature, and that the recent rapid retreat of ice cliff and less formation of sea-ice are caused especially by the warming trends in autumn accompanied with expansion of summer thawing period.

Estimating on the Erosion and Retreat Rates of Sea-cliff Slope Using the Datum-point in Pado-ri, the Western Coast of Korea (침식기준목을 이용한 파도리 해식애 사면의 침식·후퇴율 산정)

  • JANG, Dong-Ho;PARK, Ji-Hoon
    • Journal of The Geomorphological Association of Korea
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    • v.19 no.3
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    • pp.71-82
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    • 2012
  • This research was carried out to estimate annual erosion and retreat rates by using datum-point and to identify the characteristics and causes of seasonal variations of sea-cliff slope in Pado-ri, Taean-gun. In the result, the erosion and retreat rates of sea-cliff were increased from spring to summer. The rates were increased rapidly between August and October, caused by the effects of extreme weather events such as severe rainstorms and typhoons, etc. Since then, the erosion and retreat rates of sea-cliff were decreased gradually, but the rates were increased again in winter due to the storm surge and mechanical weathering resulting from the repeated freezing and thawing actions of bed rocks. The factors that affect erosion and retreat rates of sea-cliff include the number of days with antecedent participation and daily maximum wave height. In particular, it turned out that the erosion is accelerated by strong wave energy during storm surges and typhoons. The annual erosion and retreat rates of study area for the past two years(from May 2010 to May 2012) were approximately 44~60cm/yr in condition of differences in geomorphological and geological characteristics at each point. These erosion and retreat rates were found to be higher than results of previous researches. This is caused by coastal erosion forces strengthened by extreme weather events. The erosion and retreat process of sea-cliff in the study area is composed by denudation of onshore areas in addition to marine erosion(wave energy).

Prediction of Potential Shoreline Retreat by Sea Level Rise (해수면 상승에 의한 해안선의 잠재적 후퇴거리 산정)

  • 손창배
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.11 no.1
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    • pp.34-40
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    • 1999
  • Models of beach response due to sea level rise were verified by experiments and potential shoreline retreat around Korea and Japan was predicted. Wave tank experiments demonstrated that not only static retreat by water level rise but also additional retreat by wave action plays an important role in total retreat and additional retreat becomes important on the condition of high waves. The result of long-term analysis of tidal data over past 3 decades shows the tendency toward rise by an average of 1.79 mm/year, which is the result of rise in 29 regions and fall in 12 regions. Based on analyzed rate of long-term sea-level rise, potential shoreline retreats of study area after 50 years were calculated and the result shows serious loss of beach.

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A Study on the Erosion and Retreat of Sea-Cliff through the Multi-temporal Aerial Photograph Data and Field Survey: The Case Study of Taean Peninsula, Korea (다중시기 항공사진과 현장조사를 통한 해안침식 변화 연구: 태안반도를 사례로)

  • WOO, Han-byol;JANG, Dong-Ho
    • Journal of The Geomorphological Association of Korea
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    • v.17 no.4
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    • pp.71-83
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    • 2010
  • In this study, the volume of shoreline retreat at sea-cliffs in the Taean peninsula(West Coast of Korea) was estimated and their erosion and seasonal landforms characteristics changes were investigated through multi-temporal aerial photographs and field survey. Based on the analysis of aerial photographs through ortho-correction, the results show that the length of shoreline and erosion area increase as erosion at sea-cliffs occurs in Pado-li and Dundu-li. To obtain the seasonal quantitative landforms changes and retreat of sea-cliffs, we marked top, middle, and bottom datum-points, from which the distance to the nearest bedrock was repeatedly measured. In these regions, the retreat of sea-cliffs gradually increases in spring to summer, but gradually decreases in autumn. In particular, the typhoon that has a great influence on the Korean peninsula in July to September in summer would drastically increase the retreat of sea-cliffs in comparison with other seasons. As the outcrop of sea-cliffs repeats freezing and thawing in winter, the retreat of sea-cliffs increases a little due to active mechanical weathering. To know the erosion and seasonal landforms changes of sea-cliffs, we took pictures of them in every month and then analyze their condition. The retreat of sea-cliffs was repeatedly occurred by the circulation of the erosion of sea-cliff base, landslides, the formation of slope sediment debris and their erosion, in that order.

Rates and Factors of Path Widening in Seongpanak Hiking Trail of Mount Halla, Jeju Island (한라산 성판악 등산로 노폭의 확대 속도와 요인)

  • Kim, Tae-Ho
    • Journal of the Korean Geographical Society
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    • v.43 no.3
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    • pp.296-311
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    • 2008
  • In order to examine the rates and factors of path widening in Mount Halla, the retreat of path sidewalls was monitored at 32 sites of Seongpanak Hiking Trail located between 875 m and 1,400 m in elevation. The mean rate of sidewall retreat for the period 2002-2008 is 50.6 mm, equivalent to 10.0 mm/yr. The retreat rate of frozen period is 19.3 mm/yr, while the rate of unfrozen period is 4.3 mm/yr. The latter is divided into the rainy and dry periods that exhibit the retreat rates of 5.9 mm/yr and 2.9 mm/yr, respectively. The retreat rate of sidewalls is also varied with seasons; winter shows the maximum rate of 42.2 mm/yr, while summer exhibits the minimum rate of 1.3 mm/yr. Spring and fall show the intermediate rates of 13.9 mm/yr and 6.4 mm/yr, respectively. Soil hardness and elevation are not closely related to the retreat rate of sidewalls, even though the retreat rate is larger at the north-faced sidewalls than the south-faced sidewalls during the frozen period. Pipkrake is likely to be the most important factor contributing to the path widening in that the retreat of winter months accounts for 76.7% of the total retreat. The hiking trail is placed under the climatic conditions which develop pipkrake in 85 days annually. In addition, it is usual to observe the path sidewall covered with pipkrake in the freezing month of December and the thawing months of March and April. On the other hand, deflation and rainsplash erosion are not important due to the weak wind speed and the forested trail. Rainwash is also insignificant in that the path has been almost paved to mitigate trampling effects. Although biological activity is not dominant, hikers cause a large retreat of sidewalls in the thawing months since they would walk on the sidewalls to avoid snow-melting pools on the path.

Rates and Processes of Bare Patch Denudation in the Subalpine Grassland of Mt. Halla (한라산 아고산 초지대 나지의 확대속도와 침식작용)

  • Kim, Tae-Ho
    • Journal of the Korean Geographical Society
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    • v.41 no.6 s.117
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    • pp.657-669
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    • 2006
  • Rates and processes of bare patch denudation were observed at Janggumokoreum(1,710m) and Minoruem(1,600m) in order to clarify some characteristics of turf exfoliation in the subalpine grassland of Mt. Halla. The bare patches have marginal terrace fronts with a maximum height of 85 cm. The terrace risers usually develop an overhanging edge 2 to 38 cm long that eventually hangs down and protects the riser beneath. The patches are largely covered with angular pebbles and cobbles. The mean rate of riser retreat for the period 2002-2004 is 39.2 mm, equivalent to 19.6 mm/yr. However, there is a disparity of the rate of riser retreat at individual sites. The maximum rate is 131 mm measured at Janggumokoreum patch while the minimum rate is 0 mm at Minoreum patch. The rate of riser retreat also varies with seasons. The thawing season of April exhibits a maximum rate of retreat. The freezing season of October and November and the rainy season of June and July show relatively high rates of retreat. Several Processes such as frost action, aeolian deflation, rainwash, rainsplash and fauna activity cause the denudation of bare patches. In particular, the needle ire action which is combined with rainwash or deflation plays a primary role in turf exfoliation due to the diurnal freeze-thaw cycles occurred over 100 days, melted snow and strong wind in the subalpine zone of Mt. Halla. Rainwash is also an important contributing process in the rainy season because Mt. Halla has the highest precipitation in Korea. By contrast, rainsplash erosion has a minor effect on the bare patch denudation due to the overhanging edge of terrace risers. Recent increase in roe deer appears to be responsible for turf destruction.

Postcolonial Criticism and Southeast Asian Studies: Pitfalls, Retreat, and Unfulfilled Promises

  • Curaming, Rommel A.
    • SUVANNABHUMI
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    • v.7 no.2
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    • pp.3-25
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    • 2015
  • This paper reflects on the relationship between postcolonial criticism (PC) and Southeast Asian Studies. The emphasis is on the apparent premature retreat from PC as well as its unfulfilled promises and persistent pitfalls. I argue that it is premature to abandon PC because it remains relevant, even essential, in the context of the much ballyhooed age of "knowledge economy" or "information society." There is a need to take another look at its promises and to work towards fulfilling them, but at the same time be conscious of its persistent problems.

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Classification of Waterfalls in Jeju Island Based on Properties of a Lava Flow (용암류 특성에 의한 제주도 폭포의 유형화)

  • Kim, Tae-Ho
    • Journal of the Korean association of regional geographers
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    • v.18 no.2
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    • pp.129-140
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    • 2012
  • In order to examine geomorphic characteristics such as form and retreat process of waterfalls in Jeju Island, 26 waterfalls were classified based upon materials forming a fall face. The waterfalls could be categorized into three types such as single unit, multiple units and basal soft-rock based upon the number and type of a lava flow. A block fall, composed of a pile of large blocks, could be added to the typology of waterfalls in Jeju Island. While the single unit fall is distributed in a region of trachyte or trachyandecite, the multiple units fall and basal soft-rock fall are largely developed in a region of basalt or trachybasalt. A retreat process of the single unit fall is an inclination or a replacement, but the basal soft-rock fall shows a parallel retreat. The multiple units fall exhibits three types of a retreat process according to the physical properties of a lava flow. The fall face is generally vertical due to well-developed vertical joints of a lava flow.

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An Environmental Design of the Catholic Retreat Center Adopting the Theoretical Aesthetics - In the Case of the Suncheon Jesuits Spiritual Center - (신학적 미학을 적용한 가톨릭 피정시설 환경설계 - 순천 예수회 영성센터를 대상으로 -)

  • Yun, Ye-Hwa;Kim, Min;Sung, Jong-Sang
    • Journal of the Korean Institute of Landscape Architecture
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    • v.51 no.6
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    • pp.12-32
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    • 2023
  • Nowadays, the increasing number of religious travelers seeking inner healing has led to the popularity of Buddhist 'temple stays', Protestant and Catholic 'retreats' as alternative vacations. However, unlike Buddhist temples, which are inculturated, Christian retreat centers follow the formula of general recreational facilities and lack an overall framework due to relying on sponsorship. This study attempts to design appropriate outdoor environments for a retreat by reflecting 'theological aesthetics' based on the process of 'Spiritual Exercises', the main method of retreat. First, as the Spiritual Exercises are often described as an 'inner pilgrimage', the images and theological aesthetics experienced in prayer themes were examined. Next, the characteristics of the spaces required for the facility were analyzed, and the composition of religious spaces was proposed. Also the landscape resources of the site were investigated, and the retreatants' behavior to derive spatial preferences was analyzed. Overall, outdoor spaces were planned to induce a shift in consciousness and broaden the spectrum of the retreatants' experience through a physical environment consistent with the mechanism of prayer. This study aimed to implement theological aesthetics by selecting a retreat center with high potential for landscape resources. As a result, it was possible to reveal the 'poetic landscape' to effectively evoke images during 'contemplative prayer', and to support religious experience. The significance of this study lied in deriving various design vocabularies for outdoor spaces of religious facilities.