Nature and stability of atoll island shorelines: Gilbert Island chain, Kiribati, equatorial Pacific
Nature and stability of atoll island shorelines: Gilbert Island chain, Kiribati, equatorial Pacific
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环礁岛海岸线的性质和稳定性：吉尔伯特岛链、基里巴斯、赤道太平洋
DOI：
10.1111/j.1365-3091.2011.01241.x
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
E. Rankey
中科院分区：
文献类型：
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作者：
E. Rankey
环绕太平洋环礁的岛屿通常形成狭窄，低洼的土地，通常被认为特别容易受到海平面上升等全球变化的影响。由于这些低地岛屿是许多岛屿国家唯一可居住的土地，因此了解海岸线的特征以及造成变化的速度和控制是一个至关重要的问题。本研究的目的是解开的特点，沿海变化的环礁岛的吉尔伯特岛链的赤道太平洋国家基里巴斯，特别是因为它们涉及到自生海岸线过程和厄尔尼诺/南方涛动的变化。综合实地观测、差分全球定位系统数据、历史航空照片和超高分辨率遥感图像，展示了Maiana和Aranuka环礁上17个岛屿的性质、空间格局和变化率。结果表明，在2005年至2009年期间，这些岛屿上约50%的海岸线显示出明显的位置变化;一些海岸线是加积的（净速率高达约800万年-1），其他海岸线是侵蚀的（高达约1800万年-1）。 1969年至2009年期间Maiana的长期净变化率低于2005年至2009年期间测量的短期净变化率。短期和长期观测都表明，一些最大的变化发生在最大的南北向岛屿的终端附近，与粗砂和砾石的沿岸运动有关。热带低气压的直接打击和明显的季节性，被解释为是岛屿增长和海岸线动态的重要因素，并不直接影响这些赤道环礁，可以作为海岸线动态的基本控制因素而消除。类似地，四年多的观测表明，海岸线变化可能不会直接受到海平面显著变化的影响，尽管最近海岸线变化率的增加可能反映了与海平面上升率长期增加的累积效应相关的不稳定性。在全球变化的框架内，当地人为影响，自生海岸线过程和厄尔尼诺/南方涛动影响的风和波浪变化控制着这些动态海岸线的许多方面。这些结果提供了定量的见解的特点和变化率的海岸线的变化，信息至关重要的评估和减轻脆弱性的岛国，如基里巴斯。
Islands rimming Pacific atolls typically form narrow, low‐lying lands that are commonly perceived to be particularly vulnerable to global changes such as sea‐level rise. As these, low islands form the only habitable land for many island nations, understanding the character of shorelines, and the rates and controls that operate to bring about changes, is an issue of central importance. The purpose of this study is to unravel the characteristics of coastal change on atoll islands of the Gilbert Island chain of the equatorial Pacific nation of Kiribati, especially as they relate to autogenic shoreline processes and El Niño/Southern Oscillation variability. Integration of field observations, differential global positioning system data, historical aerial photographs and ultra‐high resolution remote sensing images demonstrates the nature, spatial patterns and rates of change from 17 islands on Maiana and Aranuka atolls. The results illustrate that, between 2005 and 2009, ca 50% of the shorelines on these islands displayed a discernable shift in position; some shorelines were accretionary (at net rates up to ca 8 m year−1) and others were erosional (up to ca 18 m year−1). Long‐term net rates of change on Maiana between 1969 and 2009 were lower than short‐term net rates measured between 2005 and 2009. Both short‐term and long‐term observations illustrate some of the greatest change occur near terminations of the largest, north–south oriented islands, associated with longshore movement of coarse sand and gravel. Direct hits by tropical depressions and marked seasonality, factors interpreted as being essential in island growth and shoreline dynamics elsewhere, do not directly impact these equatorial atolls and can be eliminated as fundamental controls on shoreline dynamics. Similarly, observations over four years suggested that shoreline variability probably is not influenced directly by marked sea‐level change, although a recent increase in the rates of shoreline change could reflect instability related to the cumulative effect of a long‐term increase in the rate of sea‐level rise. Within this framework of global change, local anthropogenic effects, autogenic shoreline processes and El Niño/Southern Oscillation‐influenced wind and wave variability control many aspects of these dynamic shorelines. These results provide quantitative insights into the character and variability of rates of shoreline change, information essential for evaluating and mitigating the vulnerability of island nations such as Kiribati.
马绍尔群岛马朱罗环礁波浪引起的近岸沉积物输送与长期海岸线变化的比较
DOI：
--
发表时间：
2005
期刊：
Global Environmental Research (in press)
影响因子：
--
作者：
Yokoki;H.;H.Yamano;H.Kayanne;D.Sato;Y.Minami;S.Ando;H.Shimazaki;T.Yamaguchi;M.Chikamori;A.Ishoda;H.Takagi
通讯作者：
H.Takagi