The Whole Earth Course Chapter 9 Hydrosphere 2 The Cryosphere Instructor: Dr. George A. Maul / X

Outline of the Class Earth’s Cover of Ice and Snow Glaciers Glaciated Landscapes Sea Ice Periglacial Landscapes and Permafrost Summary

What is the Cryosphere? Sea, lake, and river ice Glaciers Ice sheets Ice caps Ice shelves Frozen ground such as permafrost

Last time we said that Earth’s Cryosphere is 43,400,000 km 3 In-class Calculation: How tall would a 1 km x 1 km tower of 4.3x10 7 km 3 stand? What is the distance to the sun? Volume = Height x Length x Width 4.3x10 7 ÷ 149.6x10 6 =

HOW BIG IS THE CRYOSPHERE? Approximately 3% of all the water in the hydrosphere is contained in the Cryosphere. WHERE DO WE FIND THE CRYOSPHERE? Glaciers cover about 10% of land area. Permafrost is another 20% of land area. HOW MUCH IS SEA ICE? Two-thirds of Earth’s permanent ice cover; one-thousandth of Earth’s total ice volume.

Past Glaciation Ice cover changes Earth’s Albedo (A) Who Cares?

Average snow cover in the northern hemisphere (%) during December 1992, based on data received (left) from a microwave sensor aboard a satellite. Maximum What is a microwave satellite sensor? Today’s ice and snow coverage

MICROWAVE SENSORS Defense Meteorological Satellite Program – DMSP Scanning Multichannel Microwave Radiometer - SMMR DMSPSMMR Image

Climate Change: Arctic Sea Ice

Motion of Arctic Sea Ice

Antarctic Ice “Facts matter” Stephen Breyer Associate Justice, US Supreme Court

How would Earth’s temperature change if the ice coverage changed? Q GHE : What is the greenhouse effect? C SUN : What is the solar constant? A: What is Earth’s albedo? 4: Where does the ¼ come from?

Stefan-Boltzmann Law Units? Circa 1879 Plank’s Law IλIλ λ

What is Q GHE ?

IN CLASS CALCULATION: C SUN : What is the solar constant? where If T SUN = 5775 K, C SUN = ? r sun = 696,000 km r Earth-SUN =149,600,000 km

Albedo: Today’s value A=30%

Why the ¼ in our equation? Energy in: π r 2 Energy out: 4 π r 2 By-the-way: Q is a flux, i.e. amount per unit area per unit time Units?

IN CLASS CALCULATION: How would Earth’s temperature change if the albedo changed from 30% to 29%? minus If T EARTH(A=30%) = 288K, T EARTH(A=29%) = ?

Contorted medial moraines of Susitna Glacier in Alaska. Glaciers

Where do we find glaciers?

 28m How thick can glaciers be? How thick is 3000 m? What is the height of the Crawford Building?

Main features of a valley glacier.

An expanded view of the effects of glacial ice on the geosphere.

Ice movement over meltwater has less friction than over frozen surfaces. What is the pressure (p) at the base of a 10,000 m thick glacier? p = ρ∙g∙h

IN CLASS CALCULATION: What is the pressure (p) at the base of a 10,000 m thick glacier? What are the units? What is the pressure melting point at the base of the glacier? So the ice melts at -8°C

Changes in a Glacier

Evolution of glacial carved landforms

Effects of glaciers on Earth’s surface are significant. Can you contrast the effects of streamflow and glaciers on sediment transport? Hint: Which one sorts sediments during transport?

Major glacial landforms in USA

Periglacial Landforms, Permafrost, Tundra Tundra Extent Tundra Periglacial Landform Permafrost

Feedback Which is positive feedback and which is negative feedback?

Why do icebergs float? Who was Archimedes? Sea Ice

IN CLASS CALCULATION: How high does an iceberg float? We’ll need the hydrostatic equation again p = ρ∙g∙h p – pressure, ρ – density, g – gravity, h – height ρ seawater =1025 kg·m -3 ρ ice =917 kg·m -3 (ρgh) water = (ρgh) ice so h ice = ?

What maritime disaster precipitated the formation of the International Ice Patrol?

Blowing up Icebergs?!?!

Pancake Ice – discovery of the Ekman Spiral.

Seasonal extent of sea ice in A. Southern hemisphere, and B. Northern hemisphere.

Florida Tech Student deploying FIT-built ROV under Arctic Ice What is an ROV?

How much frozen water is in sea ice? Sea ice is 0.1% of the total volume of ice on Earth. How much of Earth is covered with sea ice? 2/3 of Earth’s permanent ice cover is sea ice. This is approximately 5-6% of the surface area of Earth. Of what significance is sea ice in the Earth System? What happens if it all melts? What happens if more forms? Who cares?

Please note the size of the sheets of ice breaking off!! Approximately 1000 km 3 of glacial ice enters the sea each year as icebergs. (Can you put this number in perspective?) How wide is Florida?

earning/player/lesson12/l12la1.html Towing Icebergs Step 2: curtain icebergStep 1: circle icebergStep 3: tow iceberg

How much heat to melt sea ice? What about the Cryosphere? Sea ice is 0.1% of Cryosphere or x 10 6 km 3 or 39.4 x g of ice. For ice at 0 0 C to water at 0 0 C 330J/g or 79 cal/g is required. Total heat required to melt sea ice is 1.3 x J, or for the whole Cryosphere is 1.3 x J. For perspective, world energy consumption is approximately 4 x J/year One PB&J sandwich is about 1 million Joules!!

Transect along western Atlantic Ocean showing water masses and general circulation processes. What happens if sea ice melts here? What happens if sea ice forms here?

Post Script: Greenland Sea Deep Water Warming

Summary Cover of Ice, Snow, and Permafrost is 30% Glaciers: temperate and polar Glacier mass = accumulation - ablation Glaciated Landscapes: Plow, File, and Sled Sea Ice: >60% of area, 0.1% of volume Permafrost covers >20% of land surface

Next Time Chapter 10 – the oceans 70.8% of the Whole Earth’s Surface