Oskar Glowacki

Institute of Geophysics, Polish Academy of Sciences · Polar and Marine Research

The temporal variability of the moments of prob-ability distribution functions (pdfs) of total sea ice defor-mation rates in the Arctic is analyzed in the context of the basin-scale wind forcing acting on the ice. The pdfs are es-timated for 594 satellite-derived sea ice deformation maps from 11 winter seasons between 1996/1997 and 2007/2008, provi...

Climate-driven ice-water interactions in the contact zone between marine-terminating glaciers and the ocean surface show a dynamic and complex nature. Tidewater glaciers lose volume through the poorly-understood process of calving. A detailed description of the mechanisms controlling the course of calving is essential for the reliable estimation an...

Ambient noise oceanography is proving to be an efficient and effective tool for the study of ice-ocean interactions in the bays of marine-terminating glaciers. However, obtaining quantitative estimates of ice melting or calving processes from ambient noise requires an understanding of how sound propagation through the bay attenuates and filters the...

Freshwater fluxes from melting icebergs and glaciers are important contributors to both sea level rise and anomalies of seawater salinity in polar regions. However, the hazards encountered close to icebergs and glaciers make it difficult to quantify their melt rates directly, motivating the development of cryoacoustics as a remote sensing technique...

Accurate estimates of calving fluxes are essential in understanding small-scale glacier dynamics and quantifying the contribution of marine-terminating glaciers to both eustatic sea-level rise (SLR) and the freshwater budget of polar regions. Here we investigate the application of acoustical oceanography to measure calving flux using the underwater...

Atlantic‐type hydrography is becoming more dominant in the Svalbard fjords. Advected warm waters affect sea‐ice formation and melting rates of tidewater glaciers. Therefore, it is important to study hydrographic variability in fjords. Here, we use hydrographic data from Hornsund fjord to investigate the presence of warm water masses close to tidewa...

High frequency broadband echosounders enable the monitoring of complex dynamics, through rapid collection of high resolution, near-synoptic observations of the water column and quantitative geophysical measurements. Here, we demonstrate the applicability and utility of broadband active acoustics systems to improve observational capabilities in high...

Several climate-driven processes take place in the Arctic fjords. These include ice–ocean interactions, biodiversity and ocean circulation pattern changes, and coastal erosion phenomena. Conducting long-term oceanographic monitoring in the Arctic fjords is, therefore, essential for better understanding and predicting global environmental shifts. He...

Melting below the waterline of marine-terminating glaciers and ice sheets has the potential to remove ice that is holding back land-based ice upstream, and increase the rate of global mean sea level rise. It is difficult to observe this melting directly, and the physical processes involved remain an active area of study. As glacier ice melts, the a...

This paper presents an apparatus and associated methods for making direct in situ measurements of the ice–water boundary of small pieces of floating glacier ice. The method involves approaching ice pieces in a small boat and attaching a frame with instruments on it to them using ice screws. These types of measurements provide an opportunity to stud...

Climate shifts are particularly conspicuous in glaciated areas. Satellite and terrestrial observations show significant increases in the melting and breakup of tidewater glaciers and their influence on sea level rise and ocean mixing. Increasing melt rates are creating an urgency to better understand the link between atmospheric and oceanic conditi...

We describe the annual pattern of frontal ablation driven by submarine melting mechanisms at the Hansbreen terminus: these are reflected in the intensity and spatial distribution of calving events. Analysis of time-lapse images of the Hansbreen front in conjunction with oceanographic and meteorological data shows that calving intensity is driven pr...

This paper presents a method for making direct in-situ measurements of the ice-water boundary of small pieces of floating glacier ice. The method involves approaching ice pieces in a small boat and attaching instruments to them using ice screws. These types of measurements provide an opportunity to study small-scale processes at the ice-water inter...

Climate shifts are particularly conspicuous in the Arctic. Satellite and terrestrial observations show significant increases in the melting and breakup of Arctic tidewater glaciers and their influence on sea level rise. Increasing melt rates are creating an urgency to better understand the link between atmospheric and oceanic conditions and glacier...

Submarine-melting of ice at the glacier-ocean interface accounts for a large portion of the ice-loss at tidewater glaciers and produces sound via bubble-release. The sound production is dominant in the sub-surface region near the glacier-ocean interface. This depth-dependence of the sound is studied by melting ice blocks in a glacial bay at various...

Iceberg calving is one of the major mechanisms of ice loss from tidewater glaciers and ice sheets, but obtaining accurate estimates of ice discharge that are both continuous and accurate is a challenging task. Recent results have demonstrated the effective application of passive cryoacoustics – the use of naturally generated sounds to study the cry...

Glacier ice loss impacts sound propagation within Arctic fjords. Regular calving events contribute to a collection of floating ice fragments, known as brash ice, at the ocean surface that obstruct the natural and anthropogenic acoustic signals, yet are difficult to characterize. Transmission loss measurements using a maximum length sequence ( m-seq...

No PDF available ABSTRACT Ice sheets are expected to be major contributors to sea level rise in the coming decades and centuries. Ocean-forced melting at marine terminating glaciers has the potential to be an important driver of mass loss from these ice sheets, but is difficult to measure directly using conventional techniques, and thus remains poo...

No PDF available ABSTRACT Climate-change induced melting is leading to accelerating ice loss at tidewater glaciers worldwide. A significant component of the freshwater flux from these glaciers arises from submarine melting at the glacier-ocean interface. This melting causes a distinct acoustic signature due to the release of pressurized bubbles und...

No PDF available ABSTRACT Marine-terminating glaciers worldwide are melting rapidly in response to climate shifts, resulting in the delivery of freshwater into the oceans. Submarine melting at the glacier-water interface accounts for a significant component of the freshwater delivery from the glacier. This melting produces a distinct acoustic signa...

No PDF available ABSTRACT Melting glaciers and ice sheets are important contributors to sea level rise, but the rates at which they are losing mass are difficult to measure precisely. Using the acoustic signals produced by the rapid release of pressurized air from bubbles contained in the ice is a promising avenue for obtaining quantitative estimat...

Arctic glacial bays are among the loudest natural environments in the ocean, owing to heavy submarine melting, calving, freshwater discharge, and ice–wave interactions. Understanding the coherence and vertical directionality of the ambient sound there can provide insights about the mechanisms behind the ice loss in these regions. It can also provid...

Measurement of the geometry of marine-terminating glaciers is challenging due to the lack of stable ground areas in close proximity to the glacier. This precludes the use of fixed measuring devices and restricts the placement of ground control points. We propose a measurement procedure for marine-terminating glaciers using structure-from-motion inc...

The underwater noise emission from glacier calving is investigated by integrating acoustic and photographic observations made in a glacial bay and model pool. Similarities in the impact noise in these two settings are identified. Distinct fluid-dynamics processes are involved in sound generation: iceberg detachment, water entry, entrainment and col...

Measuring tidewater glacier melt rates with underwater noise

Accurate estimates of calving fluxes are essential to understand small-scale glacier dynamics and quantify the 10 contribution of marine-terminating glaciers to both eustatic sea level rise and the freshwater budget of polar regions. Here we investigate the application of ambient noise oceanography to measure calving flux using the underwater sound...

Transmission loss measurements were conducted in the meltwater-modified surface layer near Hansbreen Glacier in Hornsund Fjord in southwestern Svalbard in September 2017 [Deane and Glowacki, JASA 143, 1711 (2018)]. An m-sequence source signal (149 dB re 1 μPa, 11 kHz carrier frequency) was tethered at 7 m depth to a boat drifting from 0 to 200 m. T...

Transmission loss measurements were conducted in the meltwater-modified surface layer near Hansbreen Glacier in Hornsund Fjord in southwestern Svalbard in September 2017 [Deane and Glowacki, JASA 143, 1711 (2018)]. An ITC-1007 (International Transducer Corporation) source emitting an m-sequence signal (149 dB re 1 µPa, 11 kHz carrier frequency) was...

Tidewater glaciers supply large amounts of suspended particulate matter (SPM) and freshwater to fjords and affect oceanographic, sedimentological and biological processes. Our understanding of these processes, is usually limited to the short summer season. Here, we present the results of a one-year-long monitoring of the spatial variability in SPM...

Measurements of the vertical directionality of the sound of bubbles released explosively from a melting glacier terminus are presented. These data are motivated by a desire to infer ice melt rates using the sound generated by bubbles, trapped in the glacier ice at the base of the fern layer and pressurized over time, as they are released by the mel...

Marine-terminating glaciers are retreating at an unprecedented pace, largely as a result of enhanced submarine melting. However, studying ice-ocean interactions is complicated due to both harsh conditions prevailing in glacial bays and lack of scientific methods enabling continuous measurements. Recent studies have shown that high underwater noise...

A propagation experiment was undertaken in the meltwater-modified surface layer in the bay of a marine-terminating Arctic glacier. Broad-band, m-sequence transmissions were made with an International Transducer Corporation 1007 source deployed from a drifting boat tracked using gps, approximately 500 m in front of Hansbreen Glacier in Hornsund Fjor...

Recent acceleration of sea ice decline observed in the Arctic Ocean draws attention to environmental factors driving this phenomenon. One of the main conclusions is a growing need for better understanding of sea ice drift, deformation, and fracturing. In response to that call, several ambient noise recordings were carried out in the coastal zone of...

Glacierized fjords are dynamic regions, with variable oceanographic conditions and complex ice−ocean interactions, which are still poorly understood. Recent studies have shown that passive underwater acoustics offers new promising tools in this branch of polar research. Here, we present results from two field campaigns, conducted in summer 2013 and...

Glacierized fjords are dynamic regions, with variable oceanographic conditions and complex ice-ocean interactions, which are still poorly understood. Recent studies have shown that passive underwater acoustics offers new promising tools in this branch of polar research. Here, we present results from two field campaigns, conducted in summer 2013 and...

Field tests were carried out at a section of the River Vistula located within the boundaries of the Świderskie Islands nature reserve in order to analyse bathymetric changes at different discharge values during the period of 2012–2014. The paper shows that the dynamics and transport of sand-waves and sandbanks strongly influence the bathymetry of t...

Progressive climate shifts are particularly pronounced in the Polar Regions, including glacial fjords and bays. Many different tools are now widely used to investigate the rate of glaciers’ movement, intensity of calving events and subglacial freshwater outflows or changes in an ice concentration at the sea surface. However, harsh polar conditions...

The directionality of ambient noise in an Arctic tidewater glacier bay was measured using two horizontally spaced, broadband hydrophones. Segments of noise were divided into two frequency bands and analyzed for arrival angle. These data show that different classes of source radiate noise in distinct spectral bands and are spatially diverse. A previ...

Arctic and Southern Oceans are extremely noisy places. Various geophysical and biological processes generate underwater sounds at different frequencies. Using spectral, wavelet and statistical analysis, it becomes possible to distinguish almost all individual phenomena. This allows the assessment of, among other things, the rainfall intensity, vari...

The boundary between marine-terminating glaciers and the ocean is subject to rapidly changing environmental conditions. Calving events are responsible for the production of drifting icebergs and, as a result of melting, provide significant amounts of freshwater to the global ocean, also contribute to sea level rise. Therefore, the rate and scale of...

According to the most recent studies, a steady and consistent increase in the underwater noise level is observed in the Arctic fjords. This phenomenon is mainly caused by intense melting of tidewater glaciers and other associated effects. An important component of the underwater sound budget is the noise generated by gas bubbles escaping from melti...

Ocean-ice boundaries in the Arctic are dynamic regions that are receiving increasing attention as sensitive indicators of shifts in climate. Recently, there has been interest in using measurements of the underwater ambient noise in the fjords of marine-terminating glaciers as a new tool to monitor and study glacier dynamics. There already exist man...

Observational data show that deformation of the compact sea ice covering the central Arctic takes place within elongated, narrow zones separating semi-rigid floes. Localization of deformation, and a related intermittent character of internal stress in the ice, cannot be satisfactorily reproduced with present state-of-the-art numerical models, espec...