1. 1 Atmospheric Radiation – Lecture 18 PHY2505 - Lecture 18 Radiation and Climate

2. 2 Atmospheric Radiation – Lecture 18 Overview This lecture –Review of Liou –IPCC definitions of radiative forcing Next lecture –1-D radiative-convective climate models –IPCC results Final lecture –Climate and planetary atmospheres

3. 3 Atmospheric Radiation – Lecture 18 Review Chapter 2 3 4 48 Solar variability Solar absorption Thermal RT modelling Satellite observation & scattering; absorption & retrieval aerosol & emission; atmospheric gases RADIATIVE FORCINGS OBSERVATION/VALIDATION Intergovernmental Panel on Climate Change

4. 4 Atmospheric Radiation – Lecture 18 Solar variability Diurnal & latitudinal variation Measurement Structure

5. 5 Atmospheric Radiation – Lecture 18 Solar absorption & scattering Solar absorption bands Rayleigh scattering Radiative transfer equation Mie scattering Characteristics of aerosols 4 3 2 1

6. 6 Atmospheric Radiation – Lecture 18 Thermal absorption & emission Spectroscopy & line shape Radiative transfer equation I (  )=B o exp(-  1 -  2 -  3 )+ B 1 exp(-  2 -  3 ) + B 2 exp(-  3 ) + B 3 B o exp(-  1 -  2 )+ B 1 exp(-  2 )+B 2 B o exp(-  1 )+ B 1 B o

7. 7 Atmospheric Radiation – Lecture 18 IPCC Formed under WMO and UNEP in 1988 to deal with potential global climate change Working Group I assesses the scientific aspects of the climate system and climate change. Working Group II assesses the vulnerability of socio-economic and natural systems to climate change, negative and positive consequences of climate change, and options for adapting to it. Working Group III assesses options for limiting greenhouse gas emissions and otherwise mitigating climate change. The Task Force on National Greenhouse Gas Inventories is responsible for the IPCC National Greenhouse Gas Inventories Programme.

8. 8 Atmospheric Radiation – Lecture 18 IPCC: major findings

9. 9 Atmospheric Radiation – Lecture 18 IPCC: radiative forcings

10. 10 Atmospheric Radiation – Lecture 18 IPCC: radiative forcings What is the IPCC definition of radiative forcing? Sensitivity parameter

11. 11 Atmospheric Radiation – Lecture 18 IPCC: Global warming potential

12. 12 Atmospheric Radiation – Lecture 18 IPCC: Global warming potential

13. 13 Atmospheric Radiation – Lecture 18 IPCC: Global warming potential

14. 14 Atmospheric Radiation – Lecture 18 IPCC: Global warming potential