1. Institute for Climate & Atmospheric Science SCHOOL OF EARTH AND ENVIRONMENT UNIVERSITY OF LEEDS Lead bubble measurement Sarah Norris and Gerrit de Leeuw

2. UNIVERSITY OF LEEDS Institute for Climate & Atmospheric Science SCHOOL OF EARTH AND ENVIRONMENT Why study bubbles? Bursting bubbles form sea spray aerosol –which can act as cloud condensation nuclei When bubbles burst at the ocean’s surface, heat and water mass, plus associated chemicals, bacteria and viruses are transferred from the ocean to the atmosphere.

3. UNIVERSITY OF LEEDS Institute for Climate & Atmospheric Science SCHOOL OF EARTH AND ENVIRONMENT How are bubbles produced? 1)In open ocean mainly produced by wave-breaking (U10 >~ 4ms -1 ) by entraining air into the surface layer of the ocean. -however over pack ice only open water are the leads so limited space for breaking waves 2) release of gas below the ocean surface - pack ice melt may release trapped gases in the form of bubbles - biogenic bubble release

4. UNIVERSITY OF LEEDS Institute for Climate & Atmospheric Science SCHOOL OF EARTH AND ENVIRONMENT Bubble Bursting Bursting Bubbles produce: film drops – 100s or 1000s radius < 2  m. jet drops – this ejects a few (<7) drops ~2-100  m in radius.

5. UNIVERSITY OF LEEDS Institute for Climate & Atmospheric Science SCHOOL OF EARTH AND ENVIRONMENT Bubble measurement – TNO mini bubble system

6. UNIVERSITY OF LEEDS Institute for Climate & Atmospheric Science SCHOOL OF EARTH AND ENVIRONMENT Bubble imaging system The bubble imaging system records 20 Hz images of the bubbles 0.4m below the water surface every 5 minutes for 2 minutes through out each deployment.

7. UNIVERSITY OF LEEDS Institute for Climate & Atmospheric Science SCHOOL OF EARTH AND ENVIRONMENT Photograph of the bubble imaging system and 3 examples of bubble imagery captured by the TNO camera at 20 frames per second. Images processed to determine bubble sizes, and spectra averaged over user determined periods.

8. UNIVERSITY OF LEEDS Institute for Climate & Atmospheric Science SCHOOL OF EARTH AND ENVIRONMENT 15ms -1 13ms -1 10ms -1 12ms -1

9. UNIVERSITY OF LEEDS Institute for Climate & Atmospheric Science SCHOOL OF EARTH AND ENVIRONMENT Open Lead Flux Site Located near bubble camera site: –Sonic anemometer –LiCOR Li-7500 (CO 2 /H 2 O) –CLASP aerosol probe (0.24 < D < 18.5  m) –CPC total aerosol

10. UNIVERSITY OF LEEDS Institute for Climate & Atmospheric Science SCHOOL OF EARTH AND ENVIRONMENT CLASP instrument Pump Sensing head 25 cm 16 channels - 0.24 to 18.5  m diameter Flow rate 3 l/min – high sampling statistics allows 10 Hz temporal resolution Compact (25 x 8 x 6 cm) – allows collocation with sonic anemometer, short inlet tube and low flow distortion, & installation in balloon instrument package