Debris-covered glacier systems and associated glacial lake outburst flood hazards:Challenges and prospects

Glaciers respond sensitively to climate variability and change, with associated impacts on meltwater production, sea-level rise and geomorphological hazards. There is a strong societal interest in understanding the current response of all types of glacier systems to climate change and how they will continue to evolve in the context of the whole glacierized landscape. In particular, understanding the current and future behaviour of debris-covered glaciers is a 'hot topic' in glaciological research because of concerns for water resources and glacier-related hazards. The state of these glaciers is closely related to various hazardous geomorphological processes which are relatively poorly understood. Understanding the implications of debris-covered glacier evolution requires a systems approach. This includes the interplay of various factors such as local geomorphology, ice ablation patterns, debris characteristics and glacier lake growth and development. Such a broader, contextualized understanding is prerequisite to identifying and monitoring the geohazards and hydrologic implications associated with changes in the debris-covered glacier system under future climate scenarios. This paper presents a comprehensive review of current knowledge of the debris-covered glacier landsystem. Specifically, we review state-of-the-art field-based and the remote sensing-based methods for monitoring debris-covered glacier characteristics and lakes and their evolution under future climate change. We advocate a holistic process-based framework for assessing hazards associated with moraine-dammed glacio-terminal lakes that are a projected end-member state for many debris-covered glaciers under a warming climat

Recent Evolution of Glaciers in the Manaslu Region of Nepal From Satellite Imagery and UAV Data (1970–2019)

Glacierized mountain ranges such as the Himalaya comprise a variety of glacier types, including clean and debris-covered glaciers. Monitoring their behaviour over time requires an assessment of changes in area and elevation along with surface features and geomorphology. In this paper we quantify the surface evolution of glacier systems in the Manaslu region of Nepal over the last five decades using 2013/2019 multi-sensor imagery and elevation data constructed from 1970 declassified Corona imagery and 1970 declassified Corona imagery. We investigate area changes, glacier thickness, geodetic glacier mass balance and surface velocity changes at regional scales and focus on the Ponkar Glacier and Thulagi Glacier and Lake for an in-depth assessment of surface geomorphology and surface feature dynamics (ponds, vegetation and ice cliffs). The time series of surface elevation changes for the lower ablation area of Ponkar Glacier is extended using 2019 UAV-based imagery and field-based ablation rates measured over the period 2016–2019. Glaciers in the Manaslu region experienced a mean area loss of −0.26 ± 0.0001% a−1 between 1970 and 2019. The mean surface lowering was −0.20 ± 0.02 ma−1 over the period 1970 to 2013, corresponding to a regional geodetic mass balance of −0.17 ± 0.03 m w. e.a−1. Overall, debris-covered glaciers had slightly higher thinning rates compared to clean ice glaciers; lake-terminating glaciers had double thinning rates compared to land-terminating glaciers. Individual glacier mass balance was negatively controlled by glacier slope and mean glacier elevation. During the period 1970 to 2013, Ponkar Glacier had a geodetic mass balance of −0.06 ± 0.01 m w. e.a−1, inversely correlated with parts of the central trunk thickening. Between 2013 and 2019 there was a nine-fold increase in the thinning rates over the lower parts of the glacier tongue relative to the period 1970–2013. Ice-surface morphology changes between 1970 and 2019 on Ponkar Glacier include a decrease in ogives and open crevasses, an increase in ice cliffs and ponds and the expansion of the supraglacial debris and ice-surface vegetation. These changes point to reduced ice-dynamic activity and are commensurate with the observed recession and negative glacier mass balance over the last five decades.publishedVersio

Evaluating digital elevation models for glaciologic applications: An example from Nevado Coropuna, Peruvian Andes

This paper evaluates the suitability of readily available elevation data derived from recent sensors - the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and the Shuttle Radar Topography Mission (SRTM) - for glaciological applications. The study area is Nevado Coropuna (6426 m), situated in Cordillera Ampato of Southern Peru. The glaciated area was 82.6 km(2) in 1962, based on aerial photography. We estimate the glacier area to be ca. 60.8 km(2) in 2000, based on analysis of the ASTER LIB scene. We used two 1:50,000 topographic maps constructed from 1955 aerial photography to create a digital elevation model with 30 in resolution, which we used as a reference dataset. Of the various interpolation techniques examined, the TOPOGRID algorithm was found to be superior to other techniques, and yielded a DEM with a vertical accuracy of +/- 14.7 m. The 1955 DEM was compared to the SRTM DEM (2000) and ASTER DEM (2001) on a cell-by-cell basis. Steps included: validating the DEM's against field GPS survey points on rock areas; visualization techniques such as shaded relief and contour maps; quantifying errors (bias) in each DEM; correlating vertical differences between various DEM's with topographic characteristics (elevation, slope and aspect) and subtracting DEM elevations on a cell-by-cell basis. The RMS error of the SRTM DEM with respect to GPS points on non-glaciated areas was 23 m. The ASTER DEM had a RMS error of 61 m with respect to GPS points and displayed 200-300 m horizontal offsets and elevation 'spikes' on the glaciated area when compared to the DEM from topographic data. Cell-by-cell comparison of SRTM and ASTER-derived elevations with topographic data showed ablation at the toes of the glaciers (-25 m to -75 m surface lowering) and an apparent thickening at the summits. The mean altitude difference on glaciated area (SRTM minus topographic DEM) was - 5 m, pointing towards a lowering of the glacier surface during the period 1955-2000. Spurious values on the glacier surface in the ASTER DEM affected the analysis and thus prevented us from quantifying the glacier changes based on the ASTER data

Spatial patterns in glacier characteristics and area changes from 1962 to 2006 in the Kanchenjunga-Sikkim area, eastern Himalaya

This study investigates spatial patterns in glacier characteristics and area changes at decadal scales in the eastern Himalaya - Nepal (Arun and Tamor basins), India (Teesta basin in Sikkim) and parts of China and Bhutan - based on various satellite imagery: Corona KH4 imagery, Landsat 7 Enhanced Thematic Mapper Plus (ETM+) and Advanced Spaceborne Thermal Emission Radiometer (ASTER), QuickBird (QB) and WorldView-2 (WV2). We compare and contrast glacier surface area changes over the period of 1962-2000/2006 and their dependency on glacier topography (elevation, slope, aspect, percent debris cover) and climate (solar radiation, precipitation) on the eastern side of the topographic barrier (Sikkim) versus the western side (Nepal). Glacier mapping from 2000 Landsat ASTER yielded 1463 +/- 88 km(2) total glacierized area, of which 569 +/- 34 km(2) was located in Sikkim and 488 +/- 29 km(2) in eastern Nepal. Supraglacial debris covered 11% of the total glacierized area, and supraglacial lakes covered about 5.8% of the debris-covered glacier area alone. Glacier area loss (1962 to 2000) was 0.50 +/- 0.2% yr(-1), with little difference between Nepal (0.53 +/- 0.2% yr(-1)) and Sikkim (0.44 +/- 0.2% yr(-1)). Glacier area change was controlled mostly by glacier area, elevation, altitudinal range and, to a smaller extent, slope and aspect. In the Kanchenjunga-Sikkim area, we estimated a glacier area loss of 0.23 +/- 0.08% yr(-1) from 1962 to 2006 based on high-resolution imagery. On a glacier-by-glacier basis, clean glaciers exhibit more area loss on average from 1962 to 2006 (34 %) compared to debris-covered glaciers (22 %). Glaciers in this region of the Himalaya are shrinking at similar rates to those reported for the last decades in other parts of the Himalaya, but individual glacier rates of change vary across the study area with respect to local topography, percent debris cover or glacier elevations

[[alternative]]The development of mining industry in Peru and its effects of economy and society in the 1990s

碩士[[abstract]]礦業是拉丁美洲傳統的經濟產業，長期以來在拉美經濟發展中占有重要地位。尤其在秘魯礦業一直是其經濟中重要的部門之一，有時其地位甚至在農業之上。秘魯礦產資源十分豐富，蘊藏總量居世界第7位。秘魯礦產資源的特點，一是品項多，二是蘊藏量大。已探明的主要礦物有銅、鉛、鋅、金、銀、鐵、鎢、錳、錫、銻等。銀產量居世界第1位，銅、鋅產量居世界第2位，錫、鉍、銻居第3位，鉛居第4位，黃金居第5位(在拉美佔第1位)。2013年秘魯礦產出口總值達227.19億美元，占秘魯總出口金額之54％；最重要之出口礦產為銅、黃金、鉛及鋅，其中銅及黃金之出口總額便占全部礦產出口總值之78％。 1990年藤森(Alberto Fujimori)政府上臺後，開始進行經濟體制改革，大力推行國有企業私有化，開啟近年秘魯礦產業的現代化。在其任內1990-1997年期間，金屬類礦物佔秘魯出口總額44.5％。1997金屬礦類的生產佔了國民生產總值的7％，銅與黃金分佔出口金屬礦類第一及第二，並且在秘魯的五大金屬礦物(金、銅、銀、鋅、鉛)佔了40%的產值。 本論文主要研究目標為分析1990年代，在藤森執政時期私有化政策推行下，如何改善秘魯的經濟，以及礦產業在此期間有何種改革措施，足以奠定秘魯礦業的地位。並且探究在大規模提升礦業發展時對社會帶來的影響。[[abstract]]Mining industry is a traditional economy sector in Latin America. It plays an important role in the history of the economic development in Latin America. Especially it has been always a significant sector in the economy, sometimes even more important the agriculture sector. Peru is rich in mineral resources, the total reserves ranked seventh in the world. One of the features of mineral resources in Peru is the diversity of the items, the other is the amount of the reserves. The discovered main minerals are copper, lead, zinc, gold, silver, iron, tungsten, manganese, tin and antimony. The production of silver lead the first rank in the world, the production of copper and zinc ranked second, the gold ranking No. 5 in the world (in Latin America ranked first). In 2013 Peruvian mineral exports totaled 22.719 billion US dollars, accounting for 54% of Peru''s total export value; the most important mineral export were copper, gold, lead and zinc. The value of the exports of copper and gold accounted for 78% of the total export value of the mineral products. In the 1990s, the government began economic reform, vigorously promoted the privatization of state-owned enterprises, which started the moderation of Peruvian mining industry. During his tenure 1990 - 1997, the metal minerals accounted for 44.5% of Peru''s total exports. In 1997 the production of metallic mineral accounted for 7% of GDP. The copper and the gold shared the first and the second position, accounting 40% of the value in five main metallic minerals in Peru (gold, copper, silver, zinc, lead) . The main objective of this thesis is to analysis that in the 1990s, during government of Fujimori, how the policy of privatization improved the economy of Peru and made the basis of Peruvian mining industry. In the same time, research the influence on the environment and the society .[[tableofcontents]]目錄 壹、緒論 1 第一節 研究動機與目的 1 第二節 研究方法與架構 4 貳、拉美國家的出口經濟與秘魯礦業發展 7 第一節 拉美國家的初級產品出口經濟 7 第二節 秘魯的礦業模式 16 第三節 秘魯礦業發展歷史 21 參、藤森政府時期的變革 31 第一節 礦業相關法律之沿革 31 第二節 私有化改革 41 第三節 私有化浪潮下的秘魯礦業 47 肆、私有化過程中的銅礦業 61 第一節 全球銅礦業的發展 61 第二節 銅礦業與秘魯經濟 72 第三節 90年代秘魯銅礦業之發展 78 伍、礦業引起的社會議題 90 第一節 環境污染 90 第二節 手工礦業之現況 94 第三節 社會衝突 106 結論 110 附錄 116 參考書目 122 圖目錄 【圖2-1】秘魯黃金歷史產量 24 【圖2-2】1990年至2010年秘魯參與罷工人數 28 【圖3-1】採礦特許權演變 39 【圖3-2】申請探勘面積演變 40 【圖3-3】秘魯重要礦場及公司位置 48 【圖4-1】精煉銅價格及供給剩餘量演變 68 【圖4-2】秘魯主要銅礦生產區 72 【圖5-1】San Juan河流域 92 【圖5-2】秘魯主要手工採礦區地圖 97 【圖5-3】汞齊化設施(Quimbalete)使用情形 99 表目錄 【表2-1】礦物種類 17 【表3-1】秘魯礦業法律沿革 31 【表3-2】美元在秘魯直接投資 33 【表3-3】1970到1975年間秘魯國營公司在礦業投入資本額 34 【表3-4】特許權種類 37 【表3-5】金屬礦產量 49 【表3-6】礦產品出口額 52 【表3-7】1997-2000礦業平均薪資 54 【表4-1】1950-2000秘魯出口產品組成 74 【表4-2】1992-2001秘魯礦業投資 76 【表4-3】銅出口額 79 【表4-4】礦業私有化 81 【表4-5】1993年-1997年 SPCC產量及銷售量 83 【表4-6】1992年-1998年礦業執行投資 88 【表4-7】各規模公司對礦業之投資 89 【表5-1】黃金估計產量 98[[note]]學號: 601310021, 學年度: 10