Glacier monitoring and glacier-climate interactions in the tropical Andes: A review

2018

Singap J Trop Geogr

Sentinel‐2 images were used for mapping debris‐free glaciers for the first time in Cordillera Blanca. Landsat‐8 and Sentinel‐2 data were compared for glacier area estimation in 2016, obtaining comparable results. It was observed that normalized difference snow index method for glacier mapping using MSI data is less sensitive to cast shadows and steep terrain compared with Landsat data. Estimated total glacier areas in 1975, 1994, and 2016 were 726 ± 20.3 km2, 576.9 ± 15.1 km2 and 482.8 ± 7.4 km2, respectively. Glacier area in 2016 using Landsat was slightly lower (475.7 ± 16.8 km2) compared to the area estimated using MSI data. Observed glacier shrinkage between 1975 and 2016 was 33.5 per cent, which is lower compared to observed glacier area loss in the eastern cordilleras of Peru. Glacier shrinkage was higher at northern and northeastern slopes (47.9 per cent and 48.1 per cent, respectively) compared to the south‐western slopes (11.1 per cent).

Section: Resultsmentioning

confidence: 97%

Section: Discussionmentioning

confidence: 97%

Glacier mapping in the Cordillera Blanca, Peru, tropical Andes, using Sentinel‐2 and Landsat data

2018

Singap J Trop Geogr

“…It must be noted that the correlation between ENSO and water levels was high when a lag (of 3 to 6 months) was considered between the occurrence of ENSO and changes in water levels—an observation that supports previous studies (e.g. Vuille et al ., , ; Kumar & Hoerling, ; Veettil et al ., ).…”

Section: Resultsmentioning

confidence: 97%

“…Variations in precipitation have higher influence on mass balance in this region compared to variations in the air temperature (Favier et al ., ). Furthermore, it was observed in previous studies that glacier fluctuation in the tropical Andes is influenced by El Niño‐Southern Oscillation (ENSO) and Pacific Decadal Oscillation (PDO) due to the modification in the air temperature and precipitation during these periods (Arnaud et al ., ; Veettil et al ., ; ; ; Maussion et al ., ; Mernild et al ., ; Vuille et al ., ).…”

Section: Introductionmentioning

confidence: 99%

“…Ribeiro et al ., ; Veettil & Souza, ) that the recent shrinkage of glaciers in the eastern mountain ranges of Peru and Bolivia can have direct influence on Amazon Basin hydrology (Figure ). A few recent studies mentioned that the shrinkage rate of glaciers in the northeastern slopes, which is important in the hydrology of the Amazon Basin, is greater than the observed shrinkage rates in the southwestern slopes (Veettil & Souza, ; Veettil et al ., ; ; ). However, it should be noted that the relative contribution of glaciers to the streamflow towards the humid slopes of the Amazon Basin tends to decrease due to the high contributions of non‐glacial lateral runoff by orographic precipitation (Bookhagen & Strecker, ; Buytaert et al ., ).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

The influence of ENSO and PDO on tropical Andean glaciers and their impact on the hydrology of the Amazon Basin

Rocha

Grondona

et al. 2019

Singap J Trop Geogr

Recent decades, particularly since the late 1970s, have witnessed a rapid retreat of glaciers in the tropical Andes. We compiled the changes in glacier surfaces along the eastern cordilleras of the tropical Andes of Peru and Bolivia since the early 1980s from the literature. Water levels from two Brazilian river basins in the Amazon basin (one (Madeira River) glacially fed by meltwater from the Andes and the other (Envira River) non‐glacially fed), were analysed for a 30‐year period between 1985−2014. Furthermore, precipitation data near these two basins were also analysed in order to understand the differential contributions of glacier melting and rainfall. Variations in the water levels from the glacially fed Madeira River showed that some years were associated with higher water levels even when the precipitation remained low during the corresponding season (May‐October). This observation was common when El Niño events occurred during the positive phase of Pacific Decadal Oscillation (PDO). Water levels in glacier‐fed Madeira River were slightly higher during the periods where El Niño and warm PDO co‐occurred. On the other hand, water levels in the Envira River were precipitation dependent; water levels were higher when the rainfall was high.

Regional climate forcing and topographic influence on glacier shrinkage: eastern cordilleras of Peru

Intl Journal of Climatology

Wang²,

Simões

et al. 2017

Self Cite

This study assessed the influence of regional climate variability and topography on surface area changes at glacierized mountain peaks of four eastern tropical Andes cordilleras between 10.5 ∘ and 13.5 ∘ S, namely, Huaguruncho, Huaytapallana, Urubamba and Vilcabamba, during the period 1985-2015 using satellite data. Time series analysis of three key climate variables (temperature, precipitation and relative humidity) at 500 hPa level was also included. Decreasing trends in precipitation and increasing relative humidity trends were observed at the northern region. Further analysis on mean distribution of wind at 500 hPa level showed significant rising trend southwards during the austral winter. Glacierized surfaces at lower altitudes were shrinking faster than those at high altitudes as expected. However, spatial orientation of glacier retreat was not similar to nearby cordilleras such as Vilcanota and Carabaya excepting for Cordillera Urubamba. Despite the high rate of precipitation due to the humidity transport from the Amazon Basin on the eastern slopes, glaciers on the eastern and north-eastern slopes in the Cordillera Urubamba retreated at a higher rate compared with those glaciers on western and south-western sides. Whether higher retreat on the eastern sides towards the south is controlled by precipitation phase changes (rain or snow) or by increased humidity levels was discussed. Furthermore, there was a predominant snowline altitude (SLA) rising trend varying between 56 and 129 m for the studied glaciers. A sharp rise in SLAs for periods 1995-2000 and 2010-2015 was attested, coinciding with warming trends in the Pacific. The relative stability in observed SLAs between 2000 and 2010 also coincided with cooling trends in the Pacific.