SGP/AOS/C1/ - Pump failure

The ratio of CCN to CN started to noticeably decline around 20070901. After a site visit 
on 20071023, the mentor found a problem with the instrument flows and diaphragm pump.  The 
instrument was return to Boulder, CO for repair. The diaphragm pump was repaired and the 
flows re-calibrated. The instrument was returned to service 20071113. 

The CCN data show qualitative changes in the number of droplets formed with changes in 
supersaturation. Because the pump was not working properly and the flows were likely 
incorrect, the numbers are not quantitative.

• AOS CCN volumetric flowrate of sheath air(CCN_Q_sheath)
• Cloud condensation nuclei number density(N_CCN)
• AOS CCN number concentration by bin(N_CCN_dN)
• AOS CCN sample saturation setpoint value reported by instrument(CCN_ss_set)
• AOS CCN sample supersaturation calculated by model)(CCN_ss_calc)
• CCN temperature gradient(CCN_Temperature_Gradient)
• AOS CCN sample pressure(CCN_P_sample)
• AOS CCN volumetric flowrate of sample air(CCN_Q_sample)
• Bin number of lowest channel of OPC include in summation of N_CCN(N_CCN_bin_number)