Glacial areas, lake areas, and snow lines from 1975 to 2012: status of the Cordillera Vilcanota, including the Quelccaya Ice Cap, northern central Andes, Peru
Glacial areas, lake areas, and snow lines from 1975 to 2012: status of the Cordillera Vilcanota, including the Quelccaya Ice Cap, northern central Andes, Peru
复制标题
DOI：
10.5194/tc-8-359-2014
复制
发表时间：
2014-01-01
期刊：
影响因子：
5.2
通讯作者：
Bookhagen, B.
中科院分区：
文献类型：
--
作者：
Hanshaw, M. N.;Bookhagen, B.
与其他地区(无论近距离和远距离)相比，秘鲁南部热带安第斯山脉的冰川受到的关注有限，但对下游社区的农业、淡水和水电供应仍然至关重要。人们对最近冰川区域的变化以及该地区的冰川如何对气候变化做出反应，以及这些变化最终将如何影响湖泊和水的供应知之甚少。为了纠正这一点，我们使用了158张跨越近40年的多光谱卫星图像，从1975年到2012年，以获取未被研究的科迪莱拉维尔卡诺塔地区的冰川和湖泊区域轮廓，包括奎尔卡亚冰帽。此外，我们还使用光谱分解方法估计了奎尔卡亚冰帽的雪线高度。首先，自1988年以来，整个科迪勒拉维尔卡诺塔冰川地区(1988年冰川面积：361千米(2))一直在以3.99+/-1.15千米(2)年(-1)的速度下降(1988-2010年的22年平均值，95%的可信区间，n=8张图像)。自1980年以来，奎尔卡亚冰盖(1980年冰川面积：63.1千米(2))一直以0.57+/-0.10千米(-1)的速度下降(1980-2010年平均为30年，95%可信区间，n=14)。第二，与前一个十年(1988-1999年)相比，过去十年(2000-2010年)各个冰川化区域的下降速度一直在加快，平均从37.5千米增加到42.3×10(-3)千米(-2)年(-1)千米(-2)(13%)。第三，中值海拔较低的冰川比中值海拔较高的冰川下降的速度更快。具体地说，冰川的中值海拔约为5200毫微秒。退缩到更高海拔的速度类似于1myr(-1)，比中值海拔约5400 ma.s.l的冰川快。第四，随着冰川面积的减少，与冰川流域相连的湖泊中77%的湖泊面积保持稳定或大致同步增加，而未与冰川流域相连的湖泊面积下降了42%(58%保持稳定)。我们关于37年来冰川和湖泊地区的新的和详细的数据为这一地区的气候变化提供了重要的时空评估。这些数据可纳入进一步研究，以分析冰川和湖泊面积的年际变化，并评估对下游人口的水文依赖性和后果。
Glaciers in the tropical Andes of southern Peru have received limited attention compared to glaciers in other regions (both near and far), yet remain of vital importance to agriculture, fresh water, and hydropower supplies of downstream communities. Little is known about recent glacial-area changes and how the glaciers in this region respond to climate changes, and, ultimately, how these changes will affect lake and water supplies. To remedy this, we have used 158 multi-spectral satellite images spanning almost 4 decades, from 1975 to 2012, to obtain glacial-and lake-area outlines for the understudied Cordillera Vilcanota region, including the Quelccaya Ice Cap. Additionally, we have estimated the snow-line altitude of the Quelccaya Ice Cap using spectral unmixing methods. We have made the following four key observations: first, since 1988 glacial areas throughout the Cordillera Vilcanota (1988 glacial area: 361 km(2)) have been declining at a rate of 3.99 +/- 1.15 km(2) yr(-1) (22 year average, 1988-2010, with 95% confidence interval (CI), n = 8 images). Since 1980, the Quelccaya Ice Cap (1980 glacial area: 63.1 km(2)) has been declining at a rate of 0.57 +/- 0.10 km(2) yr(-1) (30 year average, 1980-2010, with 95% CI, n = 14). Second, decline rates for individual glacierized regions have been accelerating during the past decade (2000-2010) as compared to the preceding decade (1988-1999) with an average increase from 37.5 to 42.3 x 10(-3) km(2) yr(-1) km(-2) (13 %). Third, glaciers with lower median elevations are declining at higher rates than those with higher median elevations. Specifically, glaciers with median elevations around 5200 ma.s.l. are retreating to higher elevations at a rate of similar to 1myr(-1) faster than glaciers with median elevations around 5400 ma.s.l. Fourth, as glacial regions have decreased, 77% of lakes connected to glacial watersheds have either remained stable or shown a roughly synchronous increase in lake area, while 42% of lakes not connected to glacial watersheds have declined in area (58% have remained stable). Our new and detailed data on glacial and lake areas over 37 years provide an important spatiotemporal assessment of climate variability in this area. These data can be integrated into further studies to analyze inter-annual glacial and lake-area changes and assess hydrologic dependence and consequences for downstream populations.