Ship-Based Measurement of the Aerosol below the Southeastern Pacific Stratocumulus Deck Jason Tomlinson, Run Jun Li, and Don Collins 24th Annual AAAR Conference October 20, 2005 Texas A&M University Acknowledgements: NOAA Atmospheric Climate and Chemistry Program, ETL, WHOI, and the crew of the R/V Revelle and Brown.

Motivation One of the most persistent stratocumulus cloud deck. A profound cooling effect on the global climate. Few in-situ measurements have been made. The most recent measurements were during Epic 2001 using a condensation nuclei counter. The goal of the project was to study the interplay between aerosols and the stratocumulus cloud deck. 1 1. Klein and Hartmann, 1993 Introduction Distributions & Growth Factors Volatility Measurements CCN Concentration Summary

Cruise Overview November 2003 December 2004 78 Measurement Sequences 13 Volatility measurements Brazil Peru Bolivia Chile Argentina Introduction Distributions & Growth Factors Volatility Measurements CCN Concentration Summary

Measurement Sequence DMA Scan DMA FLOW Introduction Summary Distributions & Growth Factors Volatility Measurements CCN Concentration Summary

Measurement Sequence TDMA Scan DMA FLOW Introduction Summary 85 % RH Distributions & Growth Factors Volatility Measurements CCN Concentration Summary

Measurement Sequence Dry Volatility Scan DMA FLOW Introduction Summary 20 % RH Introduction Distributions & Growth Factors Volatility Measurements CCN Concentration Summary

2003 Number Distributions Trough Location 0.085 ± 0.014 mm Number Concentration 395 ± 142 cm-3 Number Concentration (> 2s discarded) 380 ± 113 cm-3 Introduction Distributions & Growth Factors Volatility Measurements CCN Concentration Summary

2003 Growth Factors 0.013 mm 0.025 mm 0.050 mm 0.100 mm 0.200 mm Introduction Distributions & Growth Factors Volatility Measurements CCN Concentration Summary

2003 Growth Factors 0.013 mm 0.025 mm 0.050 mm 0.100 mm 0.200 mm Introduction Distributions & Growth Factors Volatility Measurements CCN Concentration Summary

2003 Growth Factors 0.2 mm 1.43 ± 0.07 0.05 mm 1.40 ± 0.07 Introduction Distributions & Growth Factors Volatility Measurements CCN Concentration Summary

2004 Number Distributions Trough Location 0.091 ± 0.008 mm Number Concentration 362 ± 210 cm-3 Number Concentration (> 2s discarded) 331 ± 124 cm-3 Introduction Distributions & Growth Factors Volatility Measurements CCN Concentration Summary

2004 Growth Factors 0.2 mm 1.49 ± 0.11 0.05 mm 1.43 ± 0.08 Introduction Distributions & Growth Factors Volatility Measurements CCN Concentration Summary

2004 Volatility Measurements 0.050 mm 0.200 mm Introduction Distributions & Growth Factors Volatility Measurements CCN Concentration Summary

2004 Volatility Measurements 0.050 mm Ammonium Bisulfate Sulfuric Acid 0.200 mm Introduction Distributions & Growth Factors Volatility Measurements CCN Concentration Summary

2004 Volatility Measurements 0.050 mm 0.200 mm Introduction Distributions & Growth Factors Volatility Measurements CCN Concentration Summary

2004 Volatility Measurements Sulfuric Acid & Ammonium Bisulfate Core Ammonium Bisulfate Core 50 0C 150 0C ? 250 0C Introduction Distributions & Growth Factors Volatility Measurements CCN Concentration Summary

2004 Volatility Measurements (0.050 mm) 1.00 ± 0.02 0.86 ± 0.07 0.49 ± 0.11 Introduction Distributions & Growth Factors Volatility Measurements CCN Concentration Summary

2004 Volatility Measurements (0.200 mm) 1.00 ± 0.01 0.62 ± 0.08 0.09 ± 0.01 Introduction Distributions & Growth Factors Volatility Measurements CCN Concentration Summary

2004 NH4/S04 0.66 ± 0.15 0.22 ± 0.10 Introduction Summary 1. 2. 3. Distributions & Growth Factors Volatility Measurements CCN Concentration Summary

CCN Concentration CCN Concentration 158 cm-3 Introduction Summary Distributions & Growth Factors Volatility Measurements CCN Concentration Summary

2003 CCN Concentration 184 ± 83 cm-3 Unperturbed: 162 ± 87 cm-3 Brazil Unperturbed: 162 ± 87 cm-3 Peru Bolivia Chile Argentina Introduction Distributions & Growth Factors Volatility Measurements CCN Concentration Summary

2004 CCN Concentration 179 ± 63 cm-3 Unperturbed: 170 ± 28 cm-3 Brazil Unperturbed: 170 ± 28 cm-3 Peru Bolivia Chile Argentina Introduction Distributions & Growth Factors Volatility Measurements CCN Concentration Summary

Summary A TDMA system was operated during November of 2003 and December of 2004 underneath the stratocumulus deck of the Southeastern Pacific. In 2003, the average total number concentration was 395 ± 142 cm-3 while the unperturbed CCN concentration was 162 ± 87 cm-3. In 2004, the average total number concentration was 362 ± 210 cm-3 while the unperturbed CCN concentration was 170 ± 28 cm-3. The aerosol was composed of a mixture of sulfuric acid and ammonium bisulfate. The NH4/S04 ratio was calculated to be 0.66 ± 0.15 and 0.22 ± 0.10 for 0.200 mm and 0.050 mm particles, respectively. Introduction Distributions & Growth Factors Volatility Measurements CCN Concentration Summary

2003 Number to Volume Ratio Introduction Conclusion Distributions & Growth Factors Volatility Measurements CCN Concentration Conclusion

2004 Number to Volume Ratio Introduction Conclusion Distributions & Growth Factors Volatility Measurements CCN Concentration Conclusion

2003 Number Concentration 0.176 ± 0.022 mm 0.050 ± 0.012 mm

2004 Number Concentration 0.214 ± 0.028 mm 0.055 ± 0.006 mm

2003 Number Distribution

2004 Number Distribution

2003 & 2004 Number Concentration   2003 2004 2003 & 2004   Average Std Dev Aitken 210.75 111.79 183.85 176.71 197.30 19.02 Accumulation 184.08 82.70 178.60 63.35 181.34 3.88 Total 394.83 142.07 362.45 210.00 378.64 22.90   2003 2004 2003 & 2004    Average Std Dev Aitken 192.28 87.95 155.36 83.12 173.82 26.11 Accumulation 179.11 77.75 168.52 46.70 7.49 Total 379.97 112.99 331.37 124.02 355.67 34.37

2003 Hygroscopic Growth Factor

2004 Hygroscopic Growth Factor

Summary A nucleation event was observed in 2003 and several mode mergers were observed between 2003 and 2004 as a result of anthropogenic emissions. Average number concentration was 353.66 ± 37.22 for 2003 and 2004 add CCN. Based on the change in particle diameter with increasing temperature, an NH4/S04 ratio for a 0.200 mm and 0.050 mm particle was calculated to be 0.655 ± 0.147 and 0.216 ± 0.102 N/V relationship of N=162.52V + 44.036 was calculated for 2003 and for 2004 the relationship was N= 36.504x + 117.55.

Summary A nucleation event was observed in 2003 and several mode mergers were observed between 2003 and 2004 as a result of anthropogenic emissions. Average number concentration was 353.66 ± 37.22 for 2003 and 2004. The aerosol is composed of a mixture of sulfuric acid and ammonium bisulfate. The NH4/S04 ratio was calculated to be 0.655 ± 0.147 and 0.216 ± 0.102 for a 0.200 mm and 0.050 mm particle, respectively.