NEGM-2015

negm-2015-notes

# NEGM 2015

## Ben Linhoff

Using radon-222 as a proxy for distributed drainage, measured from a proglacial stream in Greenland


## Mauri Pelto

**Using transient snowline migration to assess alpine glaciers**

### Taku Glacier, Juneau Ice Field

snowpits and probing
60 year record
snowline migrates up glacier
can also use satellite images

### Lemon Creek Glacier, Juneau Ice Field

data from 1998, 2003

### Mittivakkat Glacier, Greenland

### Purpose

For all of these, can compare in-situ measurements to satellite observations

transient snow line represents zero-mass-balance point, and so can be used to validate degree-day mass balance models

## APECS Announcement (Ellyn)

- APECS members get reduced IGS membership rates
- webinars (e.g. field safety)
- science communication workshops at IGS symposia (next one in Cambridge, then La Jolla)

## Magdalena Andres - PIES

freshwater in Greenland can influence:

- buoyancy-driven coastal currents
- deepwater formation / global thermohaline circulation

EGC -> WGC -> Labrador current (shelfbreak jet in New England)

> PIES sits on sea floor and emits pings every 10 min
> Round-trip time is a proxy for heat content
> sometimes get early echoes: ice bergs passing overhead? too noisy in summer, but good signal in winter.

deployed three in Sermilik, after a one-year pilot study

*Andres, Silvano, Straneo, Watts (2015) JTECH In Press*

## Stephanie Mills / Chris Gerbi

**Ice microstructure with SEM**

Role of microstructure on ice rheology

$$\dot{\epsilon} = EA \sigma ^{n}$$
where $E\sim1-10$ reflects crystal orientation

## Jessica Scheick

**Changes in iceberg size and distribution in Disko Bay**

Previous studies of iceberg distribution limited by:

- spatial reslution
- area observed
- duration of observations (seasonally, inter-annually)
- technology available

*Are waters navigable, and are they becoming more/less navigable?*

In Illulisat, local knowledge -> more small icebergs -> less navigable

**Goal**: automated algorithm

## Ken Mankoff

**Plume observations and model**

Fjord at depth is 1$^\circ$C uniform, stratification vaguely salt controlled

Max fjord depth ~150 m

Meltwater plume exported at ~ 30-40 meters (below runoff plume?)

Melt rate 11 m per day based on meltwater content of plume and assumptions about plume geometry

Plume models fail to match melt rates