1. The Global Heat Budget Air-sea exchanges of heat (& freshwater) create deep water masses & drive the conveyor belt Heat source into the ocean is solar radiation There are several heat loss terms latent, conduction, longwave radiation, reflected solar Ocean circulation moves heat (advection)

2. Solar Radiation

4. The Heat Budget Total heat flux (Q t ) = Solar radiation (Q s ) - Latent heat loss (Q e ) - Conductive heat loss (Q h ) - Longwave radiation (Q b ) Q t = Q s - Q e - Q h - Q b

5. Heat Loss Terms Latent heat flux (Q e ) – Energy required to evaporate water – Most important in tropics & midlatitudes Conductive (or sensible) heat flux (Q h ) – Loss to turbulent exchange with atmosphere –Typically small Longwave radiation (Q b ) – Net thermal IR emission from ocean

6. Global Heat Budget

7. Net Solar Radiation Typical Jan Tropics 200 W/m 2 Mid-latitudes 100 W/m 2 High-latitude ~10 W/m 2

8. Latent Heat Loss Typical Jan Tropics 120 W/m 2 Mid-latitudes 100 W/m 2 High-latitude ~20 W/m 2

9. Conductive Heat Loss Typical Jan Tropics 0-10 W/m 2 Mid-latitudes 0-40 W/m 2 High-latitude 0-30 W/m 2

10. Net Longwave Radiation Typical Jan Tropics 40-50 W/m 2 Mid-latitudes 60-70 W/m 2 High-latitude 30-50 W/m 2

11. Total Heat Flux Typical Jan Cool NH Heat - SH WBC’s -200 W/m 2 SH Subtropics 70 W/m 2 NH Subtropics > -80 W/m 2

12. Total Heat Flux Typical July Heat NH Cool SH NH Subtropics 100 W/m 2 SH Subtropics -40 W/m 2

13. Global Heat Budget

14. Global Heat Transport

15. 10 15 W = 1 Petawatt

16. Hydrographic Inverse Models WOCE hydrographic sections are used to estimate global circulation & material transport Mass, heat, salt & other properties are conserved Air-sea exchanges & removal processes are considered Provides estimates of basin scale circulation, heat & freshwater transports

17. Global Heat Transport

20. The Global Heat Budget Heat source into the ocean is solar radiation There are several heat loss terms latent, conduction, longwave radiation, reflected solar Ocean circulation moves heat (advection) Large scale heat budget can be closed by analyzing hydrographic sections