12-14 November 2005 Vatican Water and the Environment The Pontificial Academy of Sciences Water cycle and climate change Professor Lennart Bengtsson Max-Planck –Institute for Meteorology, Hamburg, Germany Environmental System Science Centre, Reading University, UK
80
Embed
12-14 November 2005 Vatican Water and the Environment The Pontificial Academy of Sciences Water cycle and climate change Professor Lennart Bengtsson Max-Planck.
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
Water cycle and climate change
Professor Lennart Bengtsson
Max-Planck –Institute for Meteorology, Hamburg, Germany
Environmental System Science Centre, Reading University, UK
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
How is the water distributed on the Earth?
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
The Heat Balance of the Atmosphere
Incoming energy from the Sun balances the outgoing energy
from the Earth
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
The Global Water Cycle
Solar forcing and atmospheric circulation are the drivers of the
water cycle
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
Annual precipitation
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
Precipitation in January
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
Precipitation in July
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
The role of the water cycle in the
climate system Precipitation is crucial for life on the planet
The largest warming factor of the atmosphere is through the relaease of latent heat amounting to 80-90 WM-2
The net transport of water from ocean to the land surfaces amounts to some 40000 km3/year
Precipitation over land is about 3 times as high
Water vapour is the dominating greenhouse gas. Removing the effect of water vapour in long wave radiation reduces climate warming at 2 x
CO2 by a factor of more than 3. (For the GFDL model from 3.38 K to 1.05 K).
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
Interannual variability in precipitation
El Nino and Southern Oscillation
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
El Nino changes precipitation patterns
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
Forest fires in Indonesia
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
Natural variability in precipitation patterns
The North Atlantic Oscillation
NAO
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
The North Atlantic Oscillation
Negative phase
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
The North Atlantic OscillationPositive phase
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
The water cycle in a warmer climate
How will it change?
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
Integrated Water vapour 1978-1999
ECHAM5: T106/L31 using AMIP2 boundary conditions
Preliminary results:
Globally averaged results vary between 25.10 mm (1985) and 26.42 mm (1998)
Mean value for the 1990s is 1% higher than in the 1980s
Interannual variations are similar as in ERA-40
Variations follow broadly temperature observations from MSU (tropospheric channel) under unchanged relative humidity (1°C is
equivalent to some 6%).
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
How does the greenhouse warming work?
Greenhouse gas warming (early ideas)
Joseph Fourier (1827)„The atmosphere is relatively transparent to solar radiation, but highly absorbent to thermal radiation“
John Tyndall (1861)Water vapour and CO2 are dominant absorbers
Water vapour feedback and climate sensitivity
Svante Arrhenius (1896)„On the influence of carbonic acid in the air upon the temperature of the ground“
Thomas C. Chamberlin (1899) „An attempt to frame a working hypothesis of the cause of glacial periods on an atmospheric basis“
„Water vapor confessedly the greatest thermal absorbent in the atmosphere is dependent on temperature for its amount and if another agent, as CO2, not so dependent, raises the temperature of the surface, it calls into function a certain amount of water vapor which further absorbs heat, raises the temperature and calls forth more vapor....“
(in a letter to C. G. Abbott, 1905).
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
How does the greenhouse warming work?
Clausius-Clapeyron relation (1832)
The fractional change in es (de/e) resulting from a small changein temperature is proportionell to T-2
A 200K, a 1K increase results in a 15 % increase in water vapour; at 300Kt it causes a 6% increase
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
• The feedback problem
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
Annual mean global values of relative humidity f (in %) vertically averaged for 850-300 hPa and vertically integrated absolute humidity q (in kg/m2).
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
• Feedback results from different models
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
IPCC on water vapour feedback
1990: The best understood feedback mechanism is water vapor feedback, and this is intuitively easy to understand.
1992: There is no compelling evidence that water vapor feedback is anything other than positive - although there may be difficulties with upper tropospheric water vapor.
1995: Feedback from the redistribution of water vapor remains a substantial source of uncertainty in climate models - Much of the current debate has been addressing feedback from thetropical upper troposphere
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
Long Term Variations in the Water Cycle
Is the Weather more extreme Today than earlier?
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
Precipitation intensity Observations and Model Results
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
Railway Station in Dresden 17 August 2002
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
17. August 2002 939 7000?31. März 1845 877 57003. Februar 1862 824 44906. September 1890 827 446012. April 1865 748 348017. März 1940 778 336020. Februar 1876 776 329017. Januar 1920 772 319011. April 1900 773 31007. Mai 1896 732 307010. März 1881 726 3090
ELBE IN DRESDEN
cm m3/s
Quelle: Deutsches Hydrologisches Jahrbuch
Extreme flooding in Elbe
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
No upward trends in the occurence of extreme floods
in central Europe
Letter to Nature, 11 September 2003
Mudelsee, Börngen, Tetzlaff and Grünewald ( Uni. Leipzig, Techn Uni Cottbus)
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
No long term Trend in Extra-tropical Storms
• WASA, 1998: Changing Waves and Storms in the North Atlantic. Bull. Amer. Met. Soc.
• Weisse, von Storch und Feser, 2004
• Alexandersson, 2004
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
Transient eddies in ECHAMHamburg latest GCM
• Roeckner et al., (2003), MPI-Report 349
• Resolution used T63L31 (top at 10hPa)
• Water vapour, cloud liquid water and cloud ice in semi-Lagrangian flux form-scheme
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
How are transient eddies identified?
• Date sets are needed at least every 6 hour• We use a method proposed by Hodges
(Hodges, 1999, MWR)• We use the vorticity at 850hPa• A transient eddy must exist for >48hours and
be extended over at least1000km
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
Storm tracks DJF 2002/03 at 850 hPaERA 40
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
Validation using ERA40present climate
• 3 AMIP-type experiments 1979-1999 using observed SST and sea-ice ( with AMIP-2 protocol ( WGNE,1996)
• ERA40 1979-2002
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
ERA 40 storm track density and intensity
DJF
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
Storm tracks ERA40 (left)ECHAM5 ( right) NH(DJF)
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
Extra-Tropical and Tropical Storms
in a warmer climate
Changes in 2070-2100 (21C)
compared to 1970-2000 (20C)
Scenario A1B
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
Change in storm track density
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
Change in storm track intensity
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
Changes in storm tracks (21C-20C)north British isles (left), Mediterranean
area (right)
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
Tropical StormsHurricanes and Typhoons
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
Ranked by the number of lives throughout the world from 1947 to 1980, the 10 major types of disaster (not including droughts and other disasters affecting agriculture) were:
Water and the EnvironmentThe Pontificial Academy of Sciences
Hurricane Floyd approaching Florida
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
But now Hurricane Katrina
Exp cost: 200G$
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
Changes in storm track density (21C-20C) MJJASO
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
Change in storm tracks (21C-20C)
number( max intensity) Tropics
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
Extreme weather conditions
(What could we expect?)
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
Climate change experiment at MPI for Met,
Hamburg
Increase in intense precipitation
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
SummaryClimate observations so far
• There are no clear indication of an intensification of the global water cycle, but precipitation has increased over many parts of high and middle latitudes of the Northern Hemisphere.
• Water vapour has increased in the atmosphere which has enhanced the greenhouse effect.
• The severe floooding incidents in recent years are in all likelyhood due to natural processes and enhanced by increasing human exposure to events caused by severe weather.
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
SummaryWhat may happen?
• Extra-tropical storms have not intensified and are not expected to intensify in a warmer climate. In western Europe the storms at the end of the 19th century were as intense as those of the last decades.
• Intense winter storms depend on the temperatur difference between Arctic and middle latitudes. An increase warming in the Arctic (melting of sea-ice) will reduce the temperature gradient.
• Convective weather systems ( mainly in Summer) are expected to intensify as the higher concentration of water vapour will be able to release more latent heat, lead to more intense precipitaion and increase risk of flooding
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
Summary Changes in the water cycle
It is expected that the overall global precipitation will increase and be more dominated by intense
precipitation.
Modell experiments indicate changes in storm tracks and weather patterns also leading to reduced
precipitation in many areas.
The largest stress on Society is likely to occur in regions with systematic reduction in precipitation.
Particularly exposed regions could be the Mediterranian and Middle East, Southern Australia
and South Africa
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
SummaryWhat may happen in the tropics?
• Higher sea surface temperatures will enhance the tropical storms (hurricanes). At the same time expected increasing vertical wind shear will reduce the positive feedback between the convective elements of the storm and the main hurricane vortex and result in a weakening of the storm.
• Model calculations show that this feedback is very important and generally leads to a reduction in the number of hurricanes. However, when and where ideal conditions exist more intense hurricanes are likely to develop.
• It is expected that the overall global precipitation will increase and be more dominated by intense precipitation.
• Modell experiments indicate changes in storm tracks and weather patterns also leading to reduced precipitation in many areas.
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
END
12-14 November 2005 Vatican
Water and the EnvironmentThe Pontificial Academy of Sciences
Content of lecture
• The Global Water Cycle• Variations in the Water Cycle on different time scales• (Is the weather now more extreme than earlier?)
• Anthropogenic Climate change and expected Consequences for the Water Cycle
• Extra-tropial and tropical Storms• Extreme Weather conditions• (What could be expected?)