ICEC-II TUTORIAL: Welcome to the tutorial for the collective intelligence project designed to allow the public to support glaciologists in their quest to understand how the Greenland and Antarctic Ice Sheets respond to a changing climate:


MAPPING Theory: Water on the surface of an ice sheet can be easily distinguished from snow and ice in satellite imagery because water is more absorbing of incident radiation from the sun, which means it reflects less energy than ice. In the visible part of the electromagnetic spectrum (EM) where your eyes are sensitive, the reflectance of water is very low while ice is very high. This property makes water look DARK in imagery when it is on the surface on an ice sheet. This illustrated in the graphic showing the reflectance of common earth surface materials. (taken from


MAPPING Training: Supraglacial hydrologic features can be distinguished by both their relative brightness (very dark features), their shape, and context. You will see that the outlet glacier can be characterized by regions that show stripping, these are fast flowing areas of ice that are heavily fractured. We call these fractures 'Crevasses'. The glacier often terminates into either a rocky coastal region or the ocean within regions we call 'Fjords'. These fjords sometimes can be filled with icebergs and debris breaking off from the edge of the glacier. Rocky coastal areas can appear dark as well in grey-scale imagery but not as dark as water. The region where the glacier terminates into the ocean is called the 'Terminus'. Once you are able to identify these features it is easy then to distinguish water bodies that are on the surface of the glacier.


TYPES OF Hydrologic Features to Map: Supraglacial hydrologic features can vary in type and location along regions of fast flow on the surface of an outlet glacier. We can classify them into two major types:


1-Supraglacial LAKES (SL)

2-Water-Filled CREVASSES (SCV)


We can also classify these features based on their relative locations along the glacier:


1-MEDIAL: near the middle of glacier flow direction

2-DISTAL: just off center of glacier flow direction

3-LATERAL: near very edge of glacier (often bordering rock)



1-Rocky Coast or outcroppings (called Nunataks)

2-Any water body or lake on the the rocky features


See the Following Examples in the Images Below Show these Features over several Outlet Glacier (arrows show ice flow direction):


Supraglacial LAKES





Water-Filled CREVASSES