Éder Leandro Bayer Maier

Variations in annual snowline and area of an ice-covered stratovolcano in the Cordillera Ampato, Peru, using remote sensing data (1986–2014)

This research focuses on the recent variations in the annual snowline and the total glaciated area of the Nevado Coropuna in the Cordillera Ampato, Peru. Maximum snowline altitude towards the end of dry season is taken as a representative of the equilibrium line altitude of the year, which is an indirect measurement of the annual mass balance. We used Landsat and IRS LISS3 images during the last 30 years due to its better temporal coverage of the study site. It is found that there was a decrease of 26.92% of the glaciated area during 1986–2014. We calculated the anomalies in precipitation and temperature in this region and also tried to correlate the changes in glacier parameters with the combined influence of El Niño – Southern Oscillation (ENSO) and pacific decadal oscillation (PDO). It is concluded that the snowline of Nevado Coropuna has been fluctuated during ENSO, and maximum fluctuations were observed when ENSO and PDO were in phase.

Influence of ENSO and PDO on mountain glaciers in the outer tropics: case studies in Bolivia

This paper emphasize on the observational investigation of an ice-covered volcano and two glaciated mountains in the Central Andes from 1984 to 2011. Annual snowlines of the Nevado Sajama in the Cordillera Occidental and the Nevado Cololo and the Nevado Huanacuni in the Cordillera Apolobamba in Bolivia were calculated using remote sensing data. Landsat TM, Landsat ETM+, and LISS-III images taken during the end of dry season were used in this study. Changes in the highest annual snowline during May–September is used an indirect measure of the changes in the equilibrium line altitude of the glaciers in the outer tropics. We tried to understand the combined influence of the El Niño-Southern Oscillation and the Pacific Decadal Oscillation on the variations in the annual snowline altitude of the selected glaciers. Meteorological data in the form of gridded datasets were used for calculating the anomalies in precipitation and temperature during the study period. It is found that the glaciated areas were fluctuated with the occurrence of warm and cold phase of ENSO but the magnitude of the influence of ENSO is observed to be controlled by the phase changes of PDO. Snowline of the Nevado Sajama fluctuated heavily when cold and warm phases of ENSO occur during the cold and warm regimes of PDO, respectively. Nevado Cololo and Nevado Huanacuni are showing a continuous retreating trend during the same period. This clearly indicates that the changes in the Pacific SST patterns have more influence on glaciers in the Cordillera Occidental compared with those in the Cordillera Oriental of the Bolivian Andes.

Recent variations of supraglacial lakes on the Baltoro Glacier in the central Karakoram Himalaya and its possible teleconnections with the pacific decadal oscillation

This study discusses the formation and variations of supraglacial lakes on the Baltoro glacier system in the central Karakoram Himalaya during the last four decades. We mapped supraglacial lakes on the Baltoro Glacier from 1978 to 2014 using Landsat MSS, TM, ETM + and LCDM images. Most of the glacial lakes were formed or expanded during the late 1970s–2008. After 2008, the total number and the area of glacial lakes were found to be lesser compared to previous years. We tried to find any teleconnections exists between the glacial lake changes in this region and the pacific decadal oscillation (PDO), which entered its prolonged warm regime in the late 1970s and again to its cold regime in 2008, based on observational investigation. The decrease in the number and area of the supraglacial lakes after 2008 is hypothesised to be linked with the recent cold phase of PDO.

Antarctica, 1979–2016 sea ice extent: total versus regional trends, anomalies, and correlation with climatological variables

ABSTRACT Antarctica satellite-derived sea ice extents (SIEs) showed a slight increase over the 1979–2010 period, generally attributed to a number of theories, including a combination of changes in atmosphere- and ocean–sea ice interactions. However, almost all authors agreed on the need of further studies based on a longer period of analysis. In this study, a 6 years longer time series (1979-2016) was analysed to calculate total and regional sea ice trends. Those trends were then correlated with three main climatological variables (air temperature, pressure, and wind components). The results showed an increased positive trend of total 1979–2016 SIE (1.6 ± 0.4% decade−1) compared to the 1979–2010 period, mostly due to the thermodynamic effect of winds. Remote factors (El Niño–Southern Oscillation and variations in equatorial Pacific and Indian oceans) also contributed to the sea ice increase by causing disturbances in the wind fields. The regional analysis confirmed the great impact of the increased westerly, katabatic and circumpolar winds, but with some differences with respect to the total trend. The increase of wind speed was stronger in the Weddell Sea and Western Pacific Ocean sectors, which corresponded to an increasing of their decadal SIE (from 1.2 ± 1.1% decade−1 to 1.7 ± 0.8% decade−1 and from 0.5 ± 1.5% decade−1 to 1.8 ± 1.2% decade−1, respectively). The Bellingshausen–Amundsen seas sector showed a decrease of its sea ice loss from −5.1 ± 1.6% decade−1 to −2.9 ± 1.4% decade−1, due to the cooling of the air temperature in the Peninsula and the increase of winds. Contrarily, two sectors – Indian Ocean and Ross Sea – showed a reduction in their increasing trends with respect to the 1979–2010 period.

Análise da relação entre o δ18O do Nevado Illimani com a distribuição espacial da precipitação sobre a América do Sul

This paper examines the relationship between an oxygen 18 isotopic ratio (δ 18 O) time series measured in an ice core from Nevado Illimani (Bolivia, 16°37’S, 6°46’W) with the precipitation spatial distribution in South America. For this, we use paleoclimatic data of the upper 50 m of the ice core and 360 layers of instrumental precipitation data between 4°N and 40°S in South America. Precipitation data were grouped by Principal Component Analysis in T-mode and the temporal occurrence of each group (Anomalous Spatial Pattern - ASP) is found when the correlation index between the principal components and the observed precipitations is greater than |0.4|. There are twelve precipitation ASPs, which result mainly from the variability of the surface temperature on the Equatorial Pacific and Tropical North Atlantic oceans. These ASPs temporal occurrence analysis and δ 18 O the time series variability indicate that the maximum (minimum) isotopic fractionation in summer is related to droughts (above mean precipitation) in the Amazon or Northeastern region of Brazil. In winter, the maximum (minimum) isotopic ratios are related to droughts (above mean precipitation in the coastal region) in the tropics and above mean precipitation (droughts) in the extratropical region.

Relações entre as razões de isótopo de oxigênio na neve e no gelo do Nevado Illimani (Bolívia) com a variabilidade temporal da precipitação sobre a América do Sul

This article examines the temporal relations between the oxygen stable isotopes ratio ( δ18O ) in an ice core from the Nevado Illimani, Bolivia (16°37’S, 67°46’W), with precipitation series from South America. We used δ 18 O data from the upper 50 m of this core and precipitation monthly totals collected at 890 weather stations in South America in the period 1979–2008. Precipitation data were arranged in a grid with ~2° latitude and longitude resolution, for zoning the spatial temporal variability, using the Principal Components Analysis Mode–S. The relation between the δ 18 O record with drought and rain events above the South America mean values changes seasonally due to spatial migration of transport mechanisms and moisture convergence. The precipitation interannual temporal variability in the equatorial and subtropical regions is the one with the greatest similarity to δ 18 O variations in the Nevado Illimani. This relationship results from the control of precipitation anomalies in the two regions by the surface temperature of the equatorial Pacific and North Atlantic oceans, at temporal frequencies from 24 to 60 months. The δ 18 O and precipitation series have temporal cycles of high spectral frequency that vary independently, as those cycles are controlled by local factors.

Analysis of snow surface dynamics in the Darwin mountain through satellite images optical and its relationship with data climate (2004–2016)

The characterization of snow surface is essential to understand the Cryosphere dynamics of the Southern Patagonia of Chile. It becomes more important when we consider that is an area of difficult access due to its geography and extreme climatic conditions. Through the processing of orbitals images from sensors TM and OLI/TIRS, present on LANDSAT 5 and 8, respectively, and their subsequent classification by an algorithm of Maximum Likelihood Supervised Classification (CSMV) and an application of the threshold to Normalized-Difference Snow Index (NDSI), were obtained for each category binary maps with classes 1 (snow) and 0 (not snow). Images were vectorized and then areas corresponding to the snow cover, in square kilometers (km2), were calculated. The variation of snow cover was correlated to precipitation and temperature data (reanalysis II NCEP/NCAR) and with Oceanic Niño Index and Antarctic Oscillation Index. The variation of snow cover indicates a decline over the study period (June 2004 to June 2016), what could be associated with global warming or remote influence, for example, ENSO and Antarctic Oscillation. But there is no homogeneous pattern of cause and consequence between snow cover variations and remote phenomenons occurrence.