Tropospheric aerosol backscatter at a midlatitude site in the northern and southern hemispheres

Rosen, James M.; Kjome, Norman T.; Liley, Ben

doi:10.1029/97jd01486

Cited by 22 publications

(16 citation statements)

References 38 publications

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“…agreement with locally high enhancements shown in Plate 1. They also agree well with reported increases in particle concentration by more than an order of magnitude above the annual average during spring near 30øS [Kristament et al, 1993] as well as with tropospheric backscatter profiles above Lauder, New Zealand [Rosen et al, 1997]. The isentropic back-trajectory analysis can provide insight into probable sources of this enhanced aerosol.…”

Section: Regionalmentioning

confidence: 55%

LITE and SAGE II measurements of aerosols in the southern hemisphere upper troposphere

Kent¹,

Trepte²,

Skeens³

et al. 1998

J. Geophys. Res.

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Abstract. Two global satellite data sets have been used to characterize the behavior of aerosols in the upper troposphere of the southern hemisphere during the spring season. The first data set was obtained by the Lidar-In-Space Technology Experiment (LITE) during 10 days in September 1994 and provides high-resolution information about aerosol layering and optical characteristics. The second data set was obtained by the Stratospheric Aerosol and Gas Experiment (SAGE) II over the time period 1984-1996 and provides information on the aerosol distribution and longterm climatology. During September, elevated aerosol layers are found to occur within a latitude band between 20øS and 40øS that extends to almost all longitudes. The latitude and altitude distribution and the optical characteristics of the aerosol suggest that a major source is smoke from biomass burning within the southern hemisphere. This conclusion is supported by the results of back-trajectory analyses that show airmasses originating in the region of southern Africa and traveling longitudinally across the Indian Ocean and Australia into the western Pacific Ocean. The dominant source of the smoke is uncertain, but quite possibly some of it may have originated from Brazil, with additions from southern Africa. The aerosol distribution shows strong similarities to published distributions for ozone and carbon monoxide, also believed to have originated from biomass burning.

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Section: Regionalmentioning

confidence: 55%

LITE and SAGE II measurements of aerosols in the southern hemisphere upper troposphere

Kent¹,

Trepte²,

Skeens³

et al. 1998

J. Geophys. Res.

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“…In previous versions, the primary method to fill missing data in the mid-and highlatitude lower stratosphere between June 1991 and mid-1993 were data from the NASA Langley 48-inch lidar facility (Osborn et al, 1995) and data from the University of Wyoming backscatter sonde (Rosen and Kjome, 1991;Rosen et al, 1997) deployed from the NIWA Lauder (New Zealand) facility. We show these data sets in Fig.…”

Section: Filling Gaps In the Sage II Data Set: Alternative Data Setsmentioning

confidence: 99%

A global space-based stratospheric aerosol climatology: 1979–2016

Thomason

Ernest²,

Millán³

et al. 2018

Earth Syst. Sci. Data

201

198

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Abstract. We describe the construction of a continuous 38-year record of stratospheric aerosol optical properties. The Global Space-based Stratospheric Aerosol Climatology, or GloSSAC, provided the input data to the construction of the Climate Model Intercomparison Project stratospheric aerosol forcing data set and we have extended it through 2016 following an identical process. GloSSAC focuses on the Stratospheric Aerosol and Gas Experiment (SAGE) series of instruments through mid-2005, and on the Optical Spectrograph and InfraRed Imager System (OSIRIS) and the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) data thereafter. We also use data from other space instruments and from ground-based, air, and balloon borne instruments to fill in key gaps in the data set. The end result is a global and gap-free data set focused on aerosol extinction coefficient at 525 and 1020 nm and other parameters on an "as available" basis. For the primary data sets, we developed a new method for filling the post-Pinatubo eruption data gap for 1991-1993 based on data from the Cryogenic Limb Array Etalon Spectrometer. In addition, we developed a new method for populating wintertime high latitudes during the SAGE period employing a latitude-equivalent latitude conversion process that greatly improves the depiction of aerosol at high latitudes compared to earlier similar efforts. We report data in the troposphere only when and where it is available. This is primarily during the SAGE II period except for the most enhanced part of the Pinatubo period. It is likely that the upper troposphere during Pinatubo was greatly enhanced over non-volcanic periods and that domain remains substantially under-characterized. We note that aerosol levels during the OSIRIS/CALIPSO period in the lower stratosphere at mid-and high latitudes is routinely higher than what we observed during the SAGE II period. While this period had nearly continuous low-level volcanic activity, it is possible that the enhancement in part reflects deficiencies in the data set. We also expended substantial effort to quality assess the data set and the product is by far the best we have produced. GloSSAC version 1.0 is available in netCDF format at the NASA Atmospheric Data Center at https://eosweb.larc.nasa.gov/. GloSSAC users should cite this paper and the data set DOI (https://doi.org/10.5067/GloSSAC-L3-V1.0).

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“…It is based on similar principles as the Wyoming backscatter sonde of Rosen and Kjome (1991), which has been used extensively in field studies (e.g., Larsen et al, 1994;Rosen et al, 1997;Beyerle et al, 2001). COBALD uses two high power (250 mW) LEDs at wavelengths centred at 455 nm (blue) and 870 nm (infrared).…”

Section: Backscatter Sonde Cobaldmentioning

confidence: 99%

Particle backscatter and relative humidity measured across cirrus clouds and comparison with microphysical cirrus modelling

et al. 2012

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Abstract. Advanced measurement and modelling techniques are employed to estimate the partitioning of atmospheric water between the gas phase and the condensed phase in and around cirrus clouds, and thus to identify in-cloud and outof-cloud supersaturations with respect to ice. In November 2008 the newly developed balloon-borne backscatter sonde COBALD (Compact Optical Backscatter and AerosoL Detector) was flown 14 times together with a CFH (Cryogenic Frost point Hygrometer) from Lindenberg, Germany (52 • N, 14 • E). The case discussed here in detail shows two cirrus layers with in-cloud relative humidities with respect to ice between 50 % and 130 %. Global operational analysis data of ECMWF (roughly 1 • × 1 • horizontal and 1 km vertical resolution, 6-hourly stored fields) fail to represent ice water contents and relative humidities. Conversely, regional COSMO-7 forecasts (6.6 km × 6.6 km, 5-min stored fields) capture the measured humidities and cloud positions remarkably well. The main difference between ECMWF and COSMO data is the resolution of small-scale vertical features responsible for cirrus formation. Nevertheless, ice water contents in COSMO-7 are still off by factors 2-10, likely reflecting limitations in COSMO's ice phase bulk scheme. Significant improvements can be achieved by comprehensive size-resolved microphysical and optical modelling along backward trajectories based on COSMO-7 wind and temperature fields, which allow accurate computation of humidities, homogeneous ice nucleation, resulting ice particle size distributions and backscatter ratios at the COBALD wavelengths. However, only by superimposing small-scale temperature fluctuations, which remain unresolved by the numerical weather prediction models, can we obtain a satisfying agreement with the observations and reconcile the measured in-cloud nonequilibrium humidities with conventional ice cloud microphysics. Conversely, the model-data comparison provides no evidence that additional changes to ice-cloud microphysics -such as heterogeneous nucleation or changing the water vapour accommodation coefficient on ice -are required.

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Tropospheric aerosol backscatter at a midlatitude site in the northern and southern hemispheres

Cited by 22 publications

References 38 publications

LITE and SAGE II measurements of aerosols in the southern hemisphere upper troposphere

LITE and SAGE II measurements of aerosols in the southern hemisphere upper troposphere

A global space-based stratospheric aerosol climatology: 1979–2016

Particle backscatter and relative humidity measured across cirrus clouds and comparison with microphysical cirrus modelling

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