Masahiro Minowa

The complex dynamics of calving glaciers is a major uncertainty in projecting global glacial mass loss. We present frontal ablation and ice mass change for the 38 major calving glaciers in the Patagonian icefields based on remote-sensing observations of ice-front positions, surface speeds and elevation changes. The frontal ablation from 2000 to 2019 was −24.1 ± 1.7 Gt a−1, which represents 34 ± 6% of the total ablation of the icefields. The fraction of frontal ablation was close to half in the s

ABSTRACT Calving plays a key role in the recent rapid retreat of glaciers around the world. However, many processes related to calving are poorly understood since direct observations are scarce and challenging to obtain. When calving occurs at a glacier front, surface-water waves arise over the ocean or a lake in front of glaciers. To study calving processes from these surface waves, we performed field observations at Glaciar Perito Moreno, Patagonia. We synchronized time-lapse photography and s

The front position of calving glaciers is controlled by ice speed and frontal ablation which consists of the two processes of calving and subaqueous melting. However, the relative importance of these processes in frontal variation is difficult to assess and poorly understood, particularly for freshwater calving glaciers. To better understand the mechanism of seasonal variations involved in the ice front variations of freshwater calving glaciers, we measured front position, ice surface speed, air

Abstract. Our study is the first to demonstrate a high-temporal-resolution record of mineral composition in a Greenland ice core over the past 100 years. To reconstruct past variations in the sources and transportation processes of mineral dust in northwestern Greenland, we analysed the morphology and mineralogical composition of dust in the SIGMA-D ice core from 1915 to 2013 using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The results revealed that the ic

ABSTRACT We recorded the ice motion and icequakes on the floating part of Langhovde Glacier in East Antarctica to better understand the dynamic behavior of ice shelves and floating tongues. Diurnal and semi-diurnal variations in ice motion and seismicity were simultaneously observed at all four global navigation satellite system and three seismic stations over 2 weeks. The short-term along-flow ice motion is explained by the elastic response of the glacier to ocean tide-induced hydrostatic stres

Measuring glacier calving magnitude, frequency and location in high temporal resolution is necessary to understand mass loss mechanisms of ocean-terminating glaciers. We utilized calving-generated tsunami signals recorded with a pressure sensor for estimating the calving flux of Bowdoin Glacier in northwestern Greenland. We find a relationship between calving ice volume and wave amplitude. This relationship was used to compute calving flux variation. The calving flux showed large spatial and tem

Abstract Calving glaciers are highly sensitive to bedrock geometry near their terminus. To understand the mechanisms controlling rapid calving glaciers’ mass loss, we measured the lake topography in front of four lake-terminating glaciers in the southern Patagonian icefield. Using remotely sensed surface elevation data, we calculated flotation height and surface slope and compared those with changes in ice-front position, surface speed and surface elevation. Rapid retreat accompanied by rapid fl

Abstract Glaciar Perito Moreno (GPM) and Glaciar Ameghino (GA), Southern Patagonia Icefield, are in contact in the accumulation area, but have shown contrasting frontal variations in the past few decades. To investigate recent changes of the two glaciers and processes controlling the different responses to similar climate conditions, we measured surface elevation change from 2000 to 2008 and terminus positions from 1999 to 2012 using several types of satellite data. GPM shows no significant chan

Basal melting of ice shelves is considered to be the principal driver of recent ice mass loss in Antarctica. Nevertheless, in-situ oceanic data covering the extensive areas of a subshelf cavity are sparse. Here we show comprehensive structures of temperature, salinity and current measured in January 2018 through four boreholes drilled at a ~3-km-long ice shelf of Langhovde Glacier in East Antarctica. The measurements were performed in 302-12 m-thick ocean cavity beneath 234-412 m-thick ice shelf

Abstract The mass budget of southern Patagonian glaciers is characterized by an extreme amount of surface ablation. To understand the processes controlling surface mass balance, we analyzed in situ data including meteorological variables and ablation stakes for the 25 years between 1996 and 2020 near the terminus of Glaciar Perito Moreno in southern Patagonia in South America. The mean annual temperature has increased over the study period at a rate of 0.2°C decade −1 . An energy-balance model w

The southern Patagonian glaciers are known for having extremely high ablation rates. Foehn winds are one of the suspected causes, however, their influence on the annual ablation, their interannual variations, and their relationship with climate change is not well understood. We analysed the in-situ meteorological data from 2003–2020 recorded at Glaciar Perito Moreno. Daily temperature lapse rates varied substantially, from −7.8°C km −1 to 10.4°C km −1 , due to foehn, fog, and katabatic winds. We

To better understand the temporal variation of the ice surface elevation and the spatio-temporal variation of snow accumulation in the accumulation area of the Southern Patagonian Icefield, we carried out a glaciological traverse in October 2018. This included measurements of surface elevation, firn layers, and sampling of snow in the accumulation areas of Glaciar Viedma and Glaciar Pío XI. The main results from the traverse are: i) during the period of 2000-2018 the surface elevation in the acc

This is the dataset of water depth observed in front of O'Higgins, Upsala, Viedma, and Tyndall glaciers in southern Patagonia. Data format: Latitude [deg], Longitude [deg], Depth [m]

These are the dataset of ice speed magnitude, error, number of valid velocity maps and elevation change rate of the Patagonian icefields (PIs) presented in the study. Please refer the main text for further technical information or directly ask the corresponding author. gererated April 2020, M. Minowa<br> updated Septempber 2020, M. Minowa =================================================================== 1. Annual velocity magnitude<br> File name: PIs_mag_utm18n_yyyy.tif<br> Format: geotiff<br>