introduction - university of iceland · sea level change in: temperature sea level snow cover...

LAN301M Fall 2012

Throstur Thorsteinsson ([email protected]) 1

Introduction

Þröstur Þorsteinsson [email protected]

Environment and Natural Resources & Institute of Earth Sciences University of Iceland

Vatnafræði / water science

Will study:

Hydrological cycle

Water and glaciers

Ground water

Surface water

Ecosystems, floods …

Oceans, sea ice, tsunami

Water and Water use

Water!

August 2010

Water Properties

Many special/unusual properties

High heat capacity

High capacity to absorb and hold heat

Universal solvent – naturally acidic

Minerals, salts

High surface tension

droplets

Lighter as a solid - than as liquid

Without this, water would freeze bottom up!

Water properties cont’

Permanent motion, from gas, liquid to solid.

Usually focus on availability in the Hydrosphere

Free water in any state in the atmosphere, on the earths surface and in the earths crust down to a depth of 2000 meters.

How much is in the hydrosphere- and where?

Phases of water

Solid

Snow

Ice

Permafrost

Liquid

Ocean

Lakes

Rivers

Vapor

– Clouds

– Hot springs

mailto:[email protected]

LAN301M Fall 2012


Water molecule

H2O – water

Ice Ih - on Earth Oxygen atom

Hydrogen atom 104.5

° H

H

O

Snowflake

Ice: Thin section

Water spheres

Include all the Earth’s water

Hydrosphere interacts with, and is influenced by, all the other “spheres”

Water sphere - schematic Distribution of Water on Earth

The distribution of Water on Earth Volume (km

3 ) %

Oceans 1 348 000 000 97.390

Polar ice caps, icebergs, glaciers 22 780 000 2.010

Ground water, soil moisture 8 062 000 0.580

Lakes and rivers 225 000 0.020 Atmosphere 13 000 0.001

SUM 1 384 120 000 100.000 Fresh water 36 020 000 2.600

LAN301M Fall 2012


Distribution of Freshwater

Fresh water as a percent of its total

Polar ice caps, glaciers 77.230

Ground water to 800 m depth 9.860

Ground water from 800 m – 4 km 12.350 Soil moisture 0.170

Lakes (fresh water) 0.350

Rivers 0.003

Hydrated earth minerals 0.001

Plants, animals, humans 0.003

Atmosphere 0.040

SUM 100.000

Water residence time

Reservoir V (%) Time Depth

Ocean 97.2 3700 a 3837 m

Ice 2.5 8600 a 190 m

Groundwater 0.63 5000 a 62 m

Surface water 10-2 1 a 147 cm

Atmosphere 10-3 1 d 25.5 mm

Water budget – reservoir fluxes

OCEANS

1350·1015 m3

LAND

33.6·1015 m3

ATMOSPHERE 0.013·1015 m3

Runoff /

Groundwater

37·1012 m3 a-1

Precipitation

99·1012 m3 a-1

Evap

ora

tio

n

36

1·1

01

2 m

3 a

-1

Pre

cipit

atio

n

32

4·1

01

2 m

3 a

-1 Evaporation/

Transpiration 62·1012 m3 a-1

Fresh water

The Hydrological Cycle

Traces the movement of water and energy

Through various stores and spheres

Evaporation - transpiration - evapotranspiration

Transfer to the atmosphere

Condensation

Vapor to liquid

Advection - movement in the atmosphere

Precipitation

Down to earth: rain, snow, hail, sleet….

Runoff

Variety of ways water moves across the land

LAN301M Fall 2012


Transport

The movement of water through the atmosphere, specifically from over the oceans to over land

Líkanreikningar á loftslagi

Parts of the hydrological cycle

Below we describe briefly the various parts of the hydrological cycle:

Condensation

Precipitation

Evaporation & Transpiration

Infiltration & Percolation

Runoff

Transport

Condensation

The cooling of water vapor until it becomes liquid

Droplets form in the sky

Form clouds, grow larger by collision and eventually precipitate

Icelandic low Precipitation

The moisture that falls from the atmosphere as rain, snow, sleet or hail

Varies in amount, intensity, and form by season

LAN301M Fall 2012


Precipitation in Iceland

Mean annual precipitation 1971 - 2000

Precipitation – 1 day Jan 2011

Floods following rains Evaporation

The phase change of liquid water into a vapor

Transfers energy between surface and air above

Energy used to evaporate water called Latent energy.

Evapotranspiration

The combined net effect of evaporation and transpiration

Evaporation returns moisture to the atmosphere

Transpiration is the process by which plants return moisture to the atmosphere

Infiltration

The entry of water into the soil surface

Sole source of water for growth of vegetation

Leaf affecting infiltration

LAN301M Fall 2012


Infiltration

Movement of water to become groundwater

Porous soil - porous bedrock foundation

Groundwater

Water found below the Earth’s surface, within the zone of saturation, below the water table

Zone saturated below water table

Is recharged in recharge zones and slowly drained in discharge zones

Percolation

The downward movement of water through soil and rock

Runoff - to Ocean

Meteorological factors affecting runoff e.g.

Type of precipitation (rain, snow, sleet, etc.)

Rainfall intensity

Rainfall amount

Rainfall duration

Direction of storm movement

Precipitation that occurred earlier and resulting soil moisture

Other meteorological and climatic conditions that affect evapotranspiration, such as temperature, wind, relative humidity, and season

Runoff to Ocean

Physical factors that affect runoff

Land use

Vegetation

Soil type

Topography, especially the slope of the land

Elevation

Ponds, lakes, reservoirs, sinks, etc. in the

basin, which prevent or delay runoff from continuing downstream

Moulin (Brunnur)

Glacier hydraulogy

Jökulhlaup

Hydro-electric power

RUSLE

Revised Universal Soil Loss Equation

Describes soil degradation as a function of:

Land use type

Precipitation

Intensity, duration

Soil type

Slope

Velocity of runoff

http://www.iwr.msu.edu/rusle/factors.htm

http://www.iwr.msu.edu/rusle/factors.htm

LAN301M Fall 2012


Groundwater

Aquifer

Is a body of groundwater that can be withdrawn mechanically or under pressure.

Soil and rock saturated with water

Unconfined

Upper boundary is the water table

No confining layer between it and the surface

Water directly from the surface

Confined

Water table above their upper boundary

Confined by an impermeable layer

A Problem? - The Aral Sea

Is drying up due to diversion for irrigation

Over 50% gone in terms of volume

Dumping ground for waste

Trying to restore

Freshwater Availability Water Stress Indicator

LAN301M Fall 2012


Freshwater stress Water Scarcity in Europe

Our future?

Can we use our water resources without depleting, and / or contaminating?

Will we have acid rain …

Water use

We will discuss how water and populations are distributed between continents

Where are problems already

Where will there be problems soon

What can we do?

Disappearing Icelandic glaciers

Snow and ice distribution

LAN301M Fall 2012


Snow

crystals

Magnification 7x

Snow flake

Transformation to ice

Transformation of snow to ice

Packing and/or settling

Further breaking of snowflakes

Thermodynamic processes

Minimizing free energy

Sintering

Deformation

Happens under load

Snow falls on surface

Snowflakes

Cryosphere

The region where ice can form

On Earth:

600 – 800 m deep

Deeper geothermal heat to high

6 – 18 km high

Moisture too low higher

Snowline

Is at:

Sea level at the poles

5500 m at 30°

5000 m at the equator

Snow-depth in January

Average snow depth in January from 1993 to 2003

LAN301M Fall 2012


Snow-depth in June

Average snow depth in January from 1993 to 2003

Earth - summer

Earth - winter What are Glaciers ?

Large mass of ice

Flowing, and possibly sliding, due to the pull of gravity

Glaciers can move at speeds ranging from several meters per year to several hundred (km) meters per year (ice streams).

Why study Glaciers ?

Impact on sea-level change

Reflection of sunlight depends on extent

Indicators of climate change

Human evolution

Water source

Hydropower

Hazards (surges, jökulhlaup)

Recreational use, ...

Glacier water

LAN301M Fall 2012


Permafrost Indicator of changing climate

Permafrost

Any subsurface matter that

remains at or below 0°C

continuously for at least two

consecutive years !

Cover about 25% of the Northern terrestrial land

surface.

Buildings and

permafrost

Buildings build on

permafrost suffer

damage to foundations.

Ice shelf

Larsen Ice Shelf, Antarctica

The Larsen Ice Shelf is one of several so-called ice shelves in

Antarctica.

Larsen B ice shelf collapse

http://youtu.be/N61EP5zB8uU

Changing climate



LAN301M Fall 2012


Media Either Hype Complex, Slow Events … or ignore

Changin environment

Making many species endangered

Penguin habitat changing

The popular ones feel the heat

Sea ice

Arctic sea ice extent Current

http://arctic.atmos.uiuc.edu/cryosphere/arctic.sea.ice.interactive.html

http://arctic.atmos.uiuc.edu/cryosphere/arctic.sea.ice.interactive.html

LAN301M Fall 2012


Arctic Animals Inuit People

Greenland Ice Cores

Ice cores extracted from the 3 km thick Greenland ice sheet preserve records of ancient air temperatures.

The records show several times when climate shifted in time spans as short as a decade.

d18O past 1200 years

Beginning of

Little Ice Age

Medieval Period

d18O past 12 ka

“8,200”

Younger Dryas

Greenland T

LAN301M Fall 2012


1858 1998

Lower Grindelwald Glacier Rhone Glacier

1870

2008

1900

Sea level

Change in: Temperature Sea level Snow cover

Problems

Problems

Why is the snow line lower at the equator than at 30° ?

The surface area of Iceland is ~103 000 km2. The total volume of ice is ~4 000 km3. (Glaciers cover about 11% of the surface of Iceland.)

How thick would the ice be if total volume spread over surface?

How thick (mean) are Icelandic glaciers?

LAN301M Fall 2012


Problems (II)

Why is there a greater variability in the sea ice cover in the South than North?

introduction - university of iceland · sea level change in: temperature sea level snow cover...

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