Measurements of size-resolved hygroscopicity in the California coastal zone

Atmospheric Chemistry and Physics Discussions 8, 310531-10560Aircraft – based measurements of aerosol hygroscopicity, both in the form of sizeresolved, diameter growth factors and in the dependence of particle light scattering on relative humidity, are presented for the marine boundary layer of the southern California coastal zone. The chemical composition of the aerosol is collated with the hygroscopicity data, both to examine the nature of aerosol aging and as input for receptor type modeling. The data suggest an increase in aerosol hygroscopicity with altitude, possibly associated with oxidation of organic films. The receptor modeling suggests three distinct aerosol types/sources for this venue: marine, biomass burning and pollution. Model output is used in regression analyses to derive a prognostic mixing rule for the hygroscopicity of aerosol with these three sources

Effects of Aerosol and SST Gradients on Marine Stratocumulus Albedo

Geophysical Research Letters, Vol. 31, No. 6, L06113, doi:10.1029/2003GL018909.The article of record as published may be located at http://dx.doi.org/10.1029/2003GL018909Airborne data are reported on the effect of sea surface temperature and aerosol gradients on the albedo of marine stratocumulus clouds off the coast of central California. Both types of gradients, at the magnitudes and spatial scales observed, produce significant and comparable trends in the cloud albedo ( 15% changes over 40 km)

Measurements of aerosol size-resolved hygroscopicity at sub and supermicron sizes

Geophysical Research Letters, Vol. 33, L21808The article of record as published may be located at http://dx.doi.org/10.1029/2006GL026747Airborne measurements of size-resolved aerosol hygroscopicity are presented using an optical particle counting and sizing technique. The measurement range of 0.25 to 3.5 mm is significantly greater, and extends to larger sizes, than previous in situ techniques. Preliminary results reveal a peak in aerosol hygroscopicity in the 0.5 –1.5 mm diameter size range in both marine and polluted aerosols. Geometric growth factors range from 1.3 to 1.5 and 1.1 to 1.3 for the sub and super-micron particles, respectively

Factors influencing the mesoscale variations in marine stratocumulus albedo

Tellus, 59B, 66-76, 2007.The article of record as published may be found at http://dx.doi.org/10.1111/j.1600-0889.2006.00231.xMeasurements of both horizontal gradients and vertical profiles of aerosols, cloud droplets and thermodynamic parameters in the cloud topped marine boundary layer off of central California are presented. They suggest that, while aerosols can indeed modulate cloud albedo, other parameters such as sea surface temperature may similarly affect cloud albedo. Additionally, the impact of aerosols, through sedimentation and precipitation, on cloud optical depths and thus albedo is not always in accord with conventional expectations and can either enhance or decrease the albedo, depending on ambient conditions. Taken together, these results suggest that current estimates of indirect forcing by aerosols could be significantly in error

Column closure studies of lower tropospheric aerosol and water vapor during ACE-Asia using airborne Sun photometer and airborne in situ and ship-based lidar measurements

Journal of Geophysical Research, 108(D23), 8656The article of record as published may be located at http://dx.doi.org/10.1029/2002JD003361.We assess the consistency (closure) between solar beam attenuation by aerosols and water vapor measured by airborne Sun photometry and derived from airborne in situ and ship-based lidar measurements during the April 2001 Asian Pacific Regional Aerosol Characterization Experiment (ACE-Asia). The airborne data presented here were obtained aboard the Twin Otter aircraft. Comparing aerosol extinction sep(550 nm) from four different techniques shows good agreement for the vertical distribution of aerosol layers. However, the level of agreement in absolute magnitude of the derived aerosol extinction varied among the aerosol layers sampled. The sep(550 nm) computed from airborne in situ size distribution and composition measurements shows good agreement with airborne Sun photometry in the marine boundary layer but is considerably lower in layers dominated by dust if the particles are assumed to be spherical. The sep(550 nm) from airborne in situ scattering and absorption measurements are about 13% lower than those obtained from airborne Sun photometry during 14 vertical profiles. Combining lidar and the airborne Sun photometer measurements reveals the prevalence of dust layers at altitudes up to 10 km with layer aerosol optical depth (from 3.5 to 10 km altitude) of 0.1 to 0.2 (500 nm) and extinction-to-backscatter ratios of 59–71 sr (523 nm). The airborne Sun photometer aboard the Twin Otter reveals a relatively dry atmosphere during ACEAsia with all water vapor columns <1.5 cm and water vapor densities rw < 12 g/m3. Comparing layer water vapor amounts and rw from the airborne Sun photometer to the same quantities measured with aircraft in situ sensors leads to a high correlation (r2 = 0.96), but the Sun photometer tends to underestimate rw by 7%

Comparison of in situ aerosol extinction and scattering coefficient measurements made during the Aerosol Intensive Operating Period

Journal of Geophysical Research, Vol. 111, No. D5, D05S03The article of record as published may be located at http://dx.doi.org/10.1029/2005JD006056.In May 2003, the Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Program sponsored the Aerosol Intensive Operating Period (AIOP) which was conducted over the ARM Climate Research Facility (ACRF) in central Oklahoma. One new instrument that flew in the AIOP, called Cadenza, employed a cavity ring-down technique to measure extinction coefficient and a reciprocal nephelometer technique to simultaneously measure scattering coefficient. This instrument is described in this paper, and measurements are compared to those of conventional instrumentation. Agreement between Cadenza extinction coefficient and that derived from combining nephelometer scattering and PSAP absorption (Neph + PSAP) was excellent, about 2%. Agreement between Cadenza scattering coefficient and TSI nephelometer scattering was also excellent, about 2%, well within the uncertainty of the nephelometer and Cadenza scattering measurements. Comparisons between these instruments, made for the special case of plumes, showed that Cadenza measured extinction and scattering several percent higher on average than the Neph + PSAP and nephelometer alone. This difference is likely due to differences in the instrument response time: The response time for Cadenza is 1 s while that for the nephelometer is a minimum of 8 s. Plumes, identified as originating from Siberian biomass burning, are characterized. Composite size distributions from wing-mounted probes showed that two of the plumes had significant large particle modes that resulted in high values of the effective radius. The effect of the large particle mode was not seen in the A ° ngstro¨m coefficient calculated from the in-cabin scattering measurements because of the characteristics of the aircraft inlet

Priorities for Bolstering Public Health Resilience in the Context of Climate Change in Dominica and Puerto Rico

Caribbean small island developing states are highly exposed to climate change impacts. Incorporating weather and climate information into public health decisions can promote resilience to climate change’s adverse health effects, but regionally it is not common practice. We implemented a project to enhance dialogue between climate and public health specialists in Puerto Rico and Dominica. First, we conducted environmental scans of public health vulnerability in the context of weather and climate for both islands. Then, we convened stakeholders to discuss the scan results and identify priorities for climate and health. A shared priority was increasing climate and health knowledge; thus, we developed several educational initiatives. In this viewpoint, we discuss our process for conducting environmental scans, building capacity and partnerships, and translating knowledge-to-action around climate and health. © 2022 The Author(s).Open access journalThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]