Section 3 Remote sensing of global change Climate change Global Change Instructor: Dr. Cheng-Chien LiuCheng-Chien Liu Department of Earth Sciences National Cheng Kung University Office: Building of Earth Sciences, room Voice: ext Office hours: Monday 14:00 – 17:00, Wednesday 9:00 – 12:00 URL: Last updated: 12 May 2005

Factors affecting climate change  Climate change  interaction of Hydrosphere Lithosphere Atmosphere  Thermometer of climate system Biosphere  Factors affecting climate change Internal factors  climate change  feedback from the atmosphere External factors  climate change  no feedback from the atmosphere

Internal factors  Constituents of atmosphere Greenhouse gasses Aerosol  Change of landform Dessert Rainforest  Ocean Short-term: El Niño Long-term: circulation of temperature and salinity

Internal factors  Cloud High altitude Low altitude  Atmospheric dynamics Butterfly effect

External factors  Sun-Earth connection Revolution  variation of eccentricity: ~0.018~0.061, T  10 5 yr Earth Rotation, Precession and Nutation  Precession: T  22,000 yr  Nutation: 22 0 ~ ~24.5 0, T  40,000 yr milankovitch_precess_high.mov milankovitch_precess_high.mov Milankovitch cycle  the Earth's inclination and orbit relative to the Sun  axis tilt  the seasonal contrast  so that winters are warmer and summers are colder  ice leftover from previous year  albedo  positive feedback  iceage

Fig. 1 Fig. 1 Sun-Earth connection. Source: image adopted from The Amosphere by Lutgens and Tarbuck, © 1998 by Prentice- Hall, Inc

External factors (cont.)  Sunspot A closer look of sunspot  e.mpg e.mpg Under the sunspot  ots.mpg ots.mpg Periodicity of Sun spot  Fig Number of sunspot  climate change ?

External factors (cont.)  Plate movement Sea-land distribution  uneven rate of heating  seasonal wind Sea-land distribution  ocean circulation  e.g. disconnection of the South America and Antarctic  Antarctic circulation  warm current is cut  T 

External factors (cont.)  Eruption of volcano Large aerosol  Absorption of long-wave radiation  warming effect  All fall down on the ground after several months Small aerosol  Scatter solar radiation  cooling effect  May stay in the stratosphere for a couple of years

Fig Fig. 2 Variations of the number of sunspot in the past three hundred years. Source:

Simulation of climate change  Manipulation and analysis of virtual weather systems constructed in cyberspace Virtual rain and electric storms – New Tools for Understanding Seasonal Climate VariationsVirtual rain and electric storms – New Tools for Understanding Seasonal Climate Variations Qualify and quantify the relationship between all factors that effect climate change  need researches! Validate the model based on real observations  satellite data is an ideal source Assimilate observations to achieve a better accuracy  optimizations of parameters that cannot be measured Stability of model prediction under normal conditions

Questions  What is the role that human plays in climate change?