Transcript Zmiany klimatu

Sources of information on climate
"proxy data" – indirect data on phenomenas
related to climate

Biological

Geomorphological

Physical

Artefacts
Physical....
Isotopes
Atomic nucleus occupies only tiny part of the whole atom.
Nucleus consists on nucleons: protons – with a positive electric charge, and
neutrons – electrically neutral.
The electric charges of proton and electron are equall. The mass of nucleons
is about 2000 times bigger than mass of electron, the mass of proton is
slightly bigger than the mass of proton (neutron = proton + electron)
Atoms with the same number of protons, but differ with the number of
neutrons are called isotopes
Atomic number of element represents the number of protons in its nucleus.
Mass number of element represents the number of nucleons (protons
and neutrons) in its nucleus.
Mass number
Atomic number
37
17
Cl
Element symbol
Isotope measurements
Some elements can have several stable isotopes – different types of atoms
with different numbers of neutrons. (Number of protons in the nucleus define
the element, number of neutrons define the isotope). The more neutrons in
the nuclues the haviers the atmos.
There are three stable isotopes of hydrogen, they are called: hydrogen(H),
deuterium (D) i tritium (T).
H H
1
1
D H
2
1
T H
3
1
Here are also two stable isotopes of oxygen:
O O
16
16
8
O O
18
18
8
The particle of water consists of two atoms of hydrogen and one atom of
oxygen. In relation of their isotopes three different water particles can be
found:
H218O,
H216O
and
HD16O
Standard Mean Ocean Water (SMOW) consists in 99,76% of H216O,
in 0,2% of H218O and in 0,03% of HD16O.
16
16


HD
O
/
H


2 Osample
D  1000 16
 1
16


 HD O / H 2 OSMOW

18
16


H
O
/
H
 2

2 Osample
18
 O  1000 18
 1
16


 H 2 O / H 2 OSMOW

The snow falling of Greenland glaciers has 18O in the range
23  -38‰.
The snow falling of Antarctic glaciers has 18O in the range -18
 -60‰.
In the case of HDO:
D  8  O 10 / 00
18
0
Ratio 18O/16O
Isotope 16O is lighter and evaporates faster than 18O. In normal conditions
it returns to ocean together with precipitation. In glacial times 16O is
trapped in the ice and a relative increase of 18O is observed in oceans. In
warm periods, ice melts and the percentage of 16O increases.
How can we use oxygen isotopes to tell air temperature in the distant
past? In high latitude climates the 18O concentration in precipitation
varies linearly with mean annual temperature.
Assuming this relationship holds for the distant past, the 18O record in
ice cores can therefore be used as a proxy for mean annual
temperature at the time of precipitation of the snow on the glacier.
During evaporation, the vapor, and hence clouds and
precipitation, are poorer in 18O water than the rest of the
water left behind. Precipitation preferentially removes
more 18O, so later precipitation is still poorer in 18O. The
tops of icecaps, which are cold and at high elevation,
receive the most 18O-poor water as precipitation. 18O in
ice therefore records air temperature.
In contrast, the oceans accumulate excess 18O as 18O-poor
water is transferred to the ice sheets. The more ice, the
richer the water becomes in 18O. Foraminifera and other
organisms growing from the water also become richer in
18O, so their skeletons in ocean sediment record the 18O
concentration in sea water and so, indirectly, record ice
volume.
Ice and ocean sediment records are therefore
complementary, each supplying different information
about ice and ice formation.
Volcanic eruptions leave dust and acids on the surface of glaciers. High
winds over dry land blow dust onto glaciers. High winds over open ocean
water produces lots of sea salt spray that can also become incorporated
into glacial ice. The snow and ice itself contain oxygen and hydrogen
isotopes, and bubbles of trapped air. All these can be analyzed to get an
idea of what is going on around the mass of glacial ice.
Ice cores
Ice cores
What we know about greenhouse gases
Climatic records in ice cores
History of Earth climate can be
reconstructed on the basis of analysis of ice
cores on Greenland and Anctarctic.
• Temperatures from measurements of
oxygen isotopes.
• Greenhouse gases in air bubbles trapped in
ice cores.
121 m deep, about 800 yrs
Project participants: Norway, The
Netherlands, Sweden, Finland,
Estonia
Austfonna
drilled in 1998 and 1999
289 m deep, about 800 yrs
Project participants: Japan, Norway
Holtedahlfonna
(Snøfjellafonna)
drilled in April 2005
125 m deep, about 400 yrs
Project participants: Norway, The
Netherlands, Sweden, Finland,
Estonia
Ice cores and climate Elisabeth Isaksson Dmitry Divine
Svalbard
drill sites
Lomonosovfonna
drilled in April 1997
Methods of Dating Ice Cores
•
•
•
•
•
Stratigraphy
Annual layers
Ratio of 18O / 16O
Electrical conductivity methods
Using volcanic eruptions as Markers
– Marker: volcanic ash and chemicals washed out of the
atmosphere by precipitation
– use recorded volcanic eruptions to calibrate age of the ice-core
– must know date of the eruption
Examples from Svalbard ice cores
Volcanic eruptions
Nuclear weapon tests
5
40
3
20
2
10
1
-1
137Cs (m Bq/k g)
60
3H (Bq/k g)
25
1963
137 Cs
Tritium(Bq/kg)
20
2-
-
30
Lomonosovfonna 2000
SO4 (eqvL )
Laki 1783
-1
NO3 (eqvL )
4
15
40
10
0
1770
1780
1790
Year (AD)
0
1800
20
5
0
0
10
20
Depth (m )
Kekonen and others, 2002
Pinglot and others, 2003
0
30
Ice cores and climate Elisabeth Isaksson Dmitry Divine
Using specific events
for dating ice cores
Ice cores have layer thinning due to pure shear which means that if sample size is
consistant the number per time unit will decrease with depth
Ice cores and climate Elisabeth Isaksson Dmitry Divine
Depth –age relationship
Oldest ever ice cores origin from
Antarctica
Last Glacial Maximum
CO2 (ppm) Antarctica
370
320
270
220
170
600000
400000 200000
czas (lata BP)
31
30
29
28
27
26
025
SST (°C) Tropical Pacific
CO2 concentration and temperature
20
31
0
30
-20
29
-40
28
-60
-80
27
-100
26
-120
25
450 400 350 300 250 200 150 100 50
0
time (thousand years BP)
SST (°C) Tropical Pacific
Sea Level (m)
Sea level during last 450 000 years
shadow.eas.gatech.edu/~kcobb/isochem/lectures/lecture8.ppt
Water isotopes in deep-sea cores
growing glaciers
deep-sea
foraminifera
The “Ice Volume” effectLight isotope removed from ocean, locked
into large ice sheets. Ocean d18O shift
(+1.5‰) recorded in marine carbonates that
grew during glacial.
SPECMAP – standard benthic d18O record,
used to date marine sediments of unknown age
shadow.eas.gatech.edu/~kcobb/isochem/lectures/lecture8.ppt
Coral records of paleo-precipitation
Theory: 1) more rain = lighter d18O
“amount” effect
2) surface seawater d18O
will become lighter
3) coral d18O lighter
Cole and Fairbanks, 1990
shadow.eas.gatech.edu/~kcobb/isochem/lectures/lecture8.ppt
Water isotopes in speleothems (cave stalagmites)
Theory:
1) δ18O of speleothem = δ18O of precipitation
2) δ8O of precipitation function of temperature (mid- to
high-latitudes) and/or amount of rainfall (low latitudes)
Wang et al., Science , 2001
After: Reconstructing & simulating past climate variability., J.F. Gonzales Rouco
After: Reconstructing & simulating past climate variability., J.F. Gonzales Rouco
Borehole temperature profiles in central Greenland
Historical data
notes about harvest, corn prices
blooming dates (cheeries from Japan more than 1000 years)
sailing conditions (ice bergs aroud Iceland)
dates of lakes freezing(Japan)
notes about weather in old church cronicles (calendars)
cave paintings
characteristic features of houses
weather descriptions
HISTORICAL DOCUMENTS
Corn prices
C. Pfister, R. Brazdil (2006)
Brazdil i in., 2005
On the wall of this house in
Wertheim, Germany, there are
marks of 24 high water events at
riversTauber and Ren
Pfister
Pfister
Weather diary,
Jan from Kunowice,
1538, Czech Republic
From the diary of Marcin Biem
Potential sources of information about temperature before 1800
Jones, Osborn and Briffa (2001) Science
Potential sources of information about humidity before 1800
Archive
Instrumental
Historical
Tree rings
measurements element
Direct T, P, SLP
Records/diaries etc. T, P, storms
Widths T, P
Density T
Isotopes T, P
Ice cores
Accumulation
Melt layers
Isotopes
Chemical composition
Corals
Growth SST, Salinity
Isotopes SST, Salinity
Chemical composition SST, Salinity
caves
Accumulation P
Isotopes T, P
Varves in lakes
Varves in the ocean
P
T
T, P
Circulation
Accumulation T
Biological composition/pollen T, P
Accumulation P
Biological/chemical cmposition T, P
Źródła wiedzy o klimacie i środowisku



Dane instrumentalne
Dane historyczne
Dane pośrednie
Dane pośrednie rzadko niosą informację o jednym
tylko elemencie pogody (klimatu).
Odczytanie informacji wymaga datowania i kalibracji
Cape Spear
Mariners’ logs, recording dates and positions of iceberg sightings
pierścienie przyrostów drzew
proporcje izotopów tlenu 18O/16O w wapiennych muszlach
mikroorganizmów oceanicznych
skład powietrza uwięzionego w lodzie grenlandzkim i antarktycznym
zasięgi gatunków o wyraźnych preferencjach klimatycznych
Western Brook Pond, Gros Morne
Hearts Delight
Okres połowicznego rozpadu
rozpad beta
W wyniku rozpadu beta
otrzymujemy pierwiastek o wyższej
liczbie atomowej
rozpad alfa
U  Th He
238
92
234
90
4
2
w wyniku rozpadu alfa
otrzymujemy pierwiastek o niższej
liczbie atomowej
Fluktuacje długości Grosser Aletsch w Alpach Szwajcarskich w ciągu
ostatnich 2000 lat.
Brazdil i in. 2005
Datowanie za pomocą węgla C-14
powstawanie
węgla C-14 w
przyrodzie
bombardowanie atmosfery
przez promieniowanie
kosmiczne
Węgiel C-14 ulega rozpadowi beta
okres połowicznego rozpadu
węgla wynosi 5730 lat
Źródła wiedzy o klimacie w przeszłości
"proxy data" – dane pośrednie o czynnikach zależnych od panujących
warunków klimatycznych:
pierścienie przyrostów drzew
proporcje izotopów tlenu 18O/16O w wapiennych muszlach
mikroorganizmów oceanicznych
skład powietrza uwięzionego w lodzie grenlandzkim i
antarktycznym
zasięgi gatunków o wyraźnych preferencjach klimatycznych