Intercomparison of Satellite Retrieved Aerosol Optical Depth over the Ocean

Myhre, Gunnar; Stordal, Frøde; Johnsrud, Mona; Ignatov, Alexander; Mischenko, M. I.; Geogdzhayev, Igor V.; Tanré, D.; Deuzé, J. L.; Goloub, Philippe; Nakajima, Teruyuki; Higurashi, Akiko; Torres, Omar; Holben, B. N.

doi:10.1175/1520-0469(2004)061<0499:iosrao>2.0.co;2

Cited by 111 publications

(130 citation statements)

References 58 publications

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“…Satellite data have greatly improved the knowledge about the distribution of aerosols in the atmosphere. Given the complicated task of retrieving aerosol information from satellite instruments (King et al, 1999), it was perhaps not surprising that Myhre et al (2004) showed, by comparing 5 satellite aerosol retrievals over ocean for an eight month period (November 1996to June 1997, that substantial differences in aerosol optical depth (AOD) are present. In general, they found differences in AOD of a factor of two between the different datasets, but in some regions it was even higher.…”

Section: Introductionsupporting

confidence: 79%

“…The aerosol plume over the Atlantic west of Africa is clearly evident, with mineral dust dominating in the northern region and biomass burning dominating in the south and a mixture of these aerosols around Equator. As in Myhre et al (2004) significant differences can be seen in the southern hemisphere at high latitudes. SeaWiFS has generally lower AOD than the three other retrievals.…”

Section: Methodsmentioning

confidence: 73%

“…This is a much longer period than studied in Myhre et al (2004) and allows investigation of inter-annual variability in AOD. For this period, 4 different aerosol satellite retrievals are investigated that were producing data for the entire period.…”

Section: Introductionmentioning

confidence: 99%

“…For this period, 4 different aerosol satellite retrievals are investigated that were producing data for the entire period. Out of these 4 retrievals, 3 were also used in the intercomparison study in Myhre et al (2004). In addition we focus on two shorter time periods; (i) an 8 months period with one additional satellite aerosol retrieval and two supplementary versions of one of the four main retrievals, (ii) a 10 months period with two additional retrievals for dedicated aerosol research.…”

Section: Introductionmentioning

confidence: 99%

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Intercomparison of satellite retrieved aerosol optical depth over ocean during the period September 1997 to December 2000

et al. 2005

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Abstract. Monthly mean aerosol optical depth (AOD) over ocean is compared from a total of 9 aerosol retrievals during a 40 months period. Comparisons of AOD have been made both for the entire period and sub periods. We identify regions where there is large disagreement and good agreement between the aerosol satellite retrievals. Significant differences in AOD have been identified in most of the oceanic regions. Several analyses are performed including spatial correlation between the retrievals as well as comparison with AERONET data. During the 40 months period studied there have been several major aerosol field campaigns as well as events of high aerosol content. It is studied how the aerosol retrievals compare during such circumstances. The differences found in this study are larger than found in a previous study where 5 aerosol retrievals over an 8 months period were compared. Part of the differences can be explained by limitations and deficiencies in some of the aerosol retrievals. In particular, results in coastal regions are promising especially for aerosol retrievals from satellite instruments particularly suited for aerosol research. In depth analyses explaining the differences between AOD obtained in different retrievals are clearly needed. We limit this study to identifying differences and similarities and indicating possible sources that affect the quality of the retrievals. This is a necessary first step towards understanding the differences and improving the retrievals.

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Section: Introductionsupporting

confidence: 79%

Section: Methodsmentioning

confidence: 73%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Intercomparison of satellite retrieved aerosol optical depth over ocean during the period September 1997 to December 2000

et al. 2005

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“…et al, 2010. Even using the same sensor channels, the variety of retrieval methods and their physical assumptions result in different aerosol optical depths [Myhre et al, 2004].…”

Section: Introductionmentioning

confidence: 99%

Introducing multisensor satellite radiance-based evaluation for regional Earth System modeling

Matsui

Santanello

Shi

et al. 2014

J. Geophys. Res. Atmos.

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Earth System modeling has become more complex, and its evaluation using satellite data has also become more difficult due to model and data diversity. Therefore, the fundamental methodology of using satellite direct measurements with instrumental simulators should be addressed especially for modeling community members lacking a solid background of radiative transfer and scattering theory. This manuscript introduces principles of multisatellite, multisensor radiance-based evaluation methods for a fully coupled regional Earth System model: NASA-Unified Weather Research and Forecasting (NU-WRF) model. We use a NU-WRF case study simulation over West Africa as an example of evaluating aerosol-cloud-precipitation-land processes with various satellite observations. NU-WRF-simulated geophysical parameters are converted to the satellite-observable raw radiance and backscatter under nearly consistent physics assumptions via the multisensor satellite simulator, the Goddard Satellite Data Simulator Unit. We present varied examples of simple yet robust methods that characterize forecast errors and model physics biases through the spatial and statistical interpretation of various satellite raw signals: infrared brightness temperature (Tb) for surface skin temperature and cloud top temperature, microwave Tb for precipitation ice and surface flooding, and radar and lidar backscatter for aerosol-cloud profiling simultaneously. Because raw satellite signals integrate many sources of geophysical information, we demonstrate user-defined thresholds and a simple statistical process to facilitate evaluations, including the infrared-microwave-based cloud types and lidar/radar-based profile classifications.

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Dimming over the oceans: Transient anthropogenic aerosol plumes in the twentieth century

et al. 2015

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Anthropogenic aerosols reduce incoming surface solar radiation (SSR), but the magnitude of this effect for reducing sea surface temperatures (SST) is still debated. Using simulations from the global climate model ECHAM5 with the Hamburg Aerosol Module and prescribed SSTs, we quantify anthropogenic aerosol dimming over sea surfaces by comparing ensembles, which only differ in anthropogenic aerosol emissions. We isolate the anthropogenic aerosol effect on SSR with sufficiently large ensemble sizes to provide statistically significant results. The following simulation results are obtained: Dimming plumes extend from their source regions with clear seasonality. The latter is predominantly shaped by atmospheric circulation, while interdecadal changes follow the gradual increase in anthropogenic aerosol emissions. Comparing the 1990s with the 1870s, on average, 9.4% (clear-sky SSR) or 15.4% (all-sky SSR) of the entire ocean surface was affected by anthropogenic aerosol dimming larger than −4 Wm −2 (decadal mean). Comparing the same time periods, global average anthropogenic dimming over oceans is −2.3 Wm −2 and −3.4 Wm −2 for clear-sky and all-sky SSR, respectively. Surface dimming is hemispherically asymmetrical with stronger Northern Hemispheric dimming by 2.3 Wm −2 and 4.5 Wm −2 for clear-sky and all-sky SSR, respectively. Zonal average clear-sky dimming reaches its maximum (−5.5 Wm −2 ) near the equator. All-sky dimming peaks at 40 ∘ N (−8 Wm −2 ) and is regionally larger than clear-sky dimming. Regionally, surface dimming can reach values up to 9.5 Wm −2 (clear-sky) and 25 Wm −2 (all-sky). Results are a contribution toward better quantifying spatially heterogeneous and time-dependent anthropogenic dimming effects on SSTs.

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Intercomparison of Satellite Retrieved Aerosol Optical Depth over the Ocean

Cited by 111 publications

References 58 publications

Intercomparison of satellite retrieved aerosol optical depth over ocean during the period September 1997 to December 2000

Intercomparison of satellite retrieved aerosol optical depth over ocean during the period September 1997 to December 2000

Introducing multisensor satellite radiance-based evaluation for regional Earth System modeling

Dimming over the oceans: Transient anthropogenic aerosol plumes in the twentieth century

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