AR5(IPCC第五次评估报告)

1、气候变化与海平面上升ProfileClimateClimate SystemIndicator of Climate ChangeSea LevelDefinition - ClimateNarrow sense： average weather: statistical description in terms of the mean and variability of relevant quantities over a period of time ranging from months to thousands or millions of years temperature pre

2、cipitation wind .Wider sense associated statistics, often combining parameters to describe phenomenaDefinition - Climate ChangeA change in the state of the climate that can be identified by changes in the mean and/or the variability of its properties, and that persists for an extended period, typica

3、lly decades or longer.Definition - Climate SystemThe Earths climate system is powered by solar radiation Main drivers of climate changeabout half of SWR is absorbed by the Earths surfaceThe fraction of SWR reflected back to space30% reflected by the Earths surface20% is absorbed in the atmosphereDef

4、inition - Climate System Main drivers of climate changeLWR emitted from the Earths surface is largely absorbed by certain atmospheric constituents water vapour, carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O) and other greenhouse gases (GHGs); clouds, which themselves emit LWR into all dire

5、ctions.Definition - Climate System Main drivers of climate changeNatural fluctuations in solar output (solar cycles) can cause changes in the energy balance (through fluctuations in the amount of incoming SWR) Human activity changes the emissions of gases and aerosols, which are involved in atmosphe

6、ric chemical reactions, resulting in modified O3 and aerosol amounts .Definition - Climate System Main drivers of climate changeCloud interactions with SWR and LWR are large, small changes in the properties of clouds have important implications for the radiative budgetAnthropogenic changes in GHGsSu

7、rface albedo is changed by changes in vegetation or land surface properties, snow or ice cover and ocean colourIndicators of Climate ChangeThere are many indicators of climate change. These include physical responses such as changes in the following: surface temperature, atmospheric water vapour, pr

8、ecipitation, severe events, glaciers, ocean and land ice, and sea level.Climate change can lead to other effects on the Earths physical system that are also indicators of climate change. Such as changes in sea levelSea LevelGlobal mean sea level is an important indicator of climate change. The previ

9、ous assessments have all shown that observations indicate that the globally averaged sea level is rising. average rate of global mean sea level rise over the 20th century was 1.7 0.2 mm yr1.This rate increased o 3.2 0.4 mm yr1since 1990 Sea Level Sea level varies as the ocean warms and cools water i

10、s transferred between the ocean and continents water is transferred between the ocean and ice sheets water is redistributed within the ocean due to tides changes in the oceanic and atmospheric circulation Measurements tide gauge to measure combine effect of ocean volume change and vertical land moti

11、on satellite radar altimeterSea LevelTrends in Global Mean Sea level and Components different approaches show very similar long-term trends computing average rates from only very long, nearly continuous records using more numerous but shorter records and filters to separate nonlinear trends from dec

12、adal-scale quasi-periodic variability neural network methods computing regional sea level for specific basins then averaging projecting tide gauge records onto EOFs computed from modern altimetry or EOFs from ocean modelsSea Level Global mean sea level anomalies (in mm) from the different measuring systemsSea LevelEstimated changes in the observed global annual mea