The relationship between marine aerosol particles and satellite‐detected radiance

Durkee, Philip A.; Jensen, D. R.; Hindman, Edward E.; Haar, Thomas H. Vonder

doi:10.1029/jd091id03p04063

Cited by 55 publications

(26 citation statements)

References 19 publications

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“…This situation suggests a way to improve the coordination between satellite and suborbital observations. First, the primary satellite retrieval product (after τ 550 ) should be å, as recommended by early investigators [ Durkee et al , 1986; Higurashi and Nakajima , 1999]. The existing validation program is excellently suited to quantifying the accuracy with which this parameter can be retrieved, whereas a systematic validation program for FMF does not exist.…”

Section: Discussionmentioning

confidence: 99%

Testing the MODIS satellite retrieval of aerosol fine‐mode fraction

et al. 2005

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[1] Satellite retrievals of the fine-mode fraction (FMF) of midvisible aerosol optical depth, t, are potentially valuable for constraining chemical transport models and for assessing the global distribution of anthropogenic aerosols. Here we compare satellite retrievals of FMF from the Moderate Resolution Imaging Spectroradiometer (MODIS) to suborbital data on the submicrometer fraction (SMF) of t. SMF is a closely related parameter that is directly measurable by in situ techniques. The primary suborbital method uses in situ profiling of SMF combined with airborne Sun photometry both to validate the in situ estimate of ambient extinction and to take into account the aerosol above the highest flight level. This method is independent of the satellite retrieval and has wellknown accuracy but entails considerable logistical and technical difficulties. An alternate method uses Sun photometer measurements near the surface and an empirical relation between SMF and the Å ngström exponent, å, a measure of the wavelength dependence of optical depth or extinction. Eleven primary and fifteen alternate comparisons are examined involving varying mixtures of dust, sea salt, and pollution in the vicinity of Korea and Japan. MODIS ocean retrievals of FMF are shown to be systematically higher than suborbital estimates of SMF by about 0.2. The most significant cause of this discrepancy involves the relationship between å and fine-mode partitioning; in situ measurements indicate a systematically different relationship from what is assumed in the satellite retrievals. Based on these findings, we recommend: (1) satellite programs should concentrate on retrieving and validating å since an excellent validation program is in place for doing this, and (2) suborbital measurements should be used to derive relationships between å and fine-mode partitioning to allow interpretation of the satellite data in terms of fine-mode aerosol optical depth.

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Section: Discussionmentioning

confidence: 99%

Testing the MODIS satellite retrieval of aerosol fine‐mode fraction

et al. 2005

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“…First, the top of atmosphere (TOA) reflectance due to an external mixture of two different aerosol types can be approximated as the weighted average of the reflectance of the individual aerosol types (Wang and Gordon, 1994). Second, the TOA reflectance is approximated as a linear function of the AOD (Durkee et al, 1986).…”

Section: Algorithms Descriptionmentioning

confidence: 99%

Spatial variation of aerosol properties over Europe derived from satellite observations and comparison with model calculations

et al. 2003

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Abstract. Aerosol optical depths (AOD) and Angström coefficients over Europe were retrieved using data from the ATSR-2 radiometer on board the ESA satellite ERS-2, for August 1997. Taking advantage of the nadir and forward view of the ATSR-2, the dual view algorithm was used over land to eliminate the influence of the surface reflection. Over sea the AOD was retrieved using only the forward observations. Retrieved aerosol optical properties are in good agreement with those from ground-based sunphotometers. The AOD and Angström coefficients together yield information on the column integrated effective aerosol distribution.Observed regional variations of the AOD and Angström coefficient are related to anthropogenic emissions of aerosol precursors such as SO 2 and NO x in the major European industrial and urban areas, and their subsequent transformation into the aerosol phase. The influence of anthropogenic aerosols such as ammonium sulphate and ammonium nitrate on the total AOD is estimated using a regional chemistry transport model. Sulphate is estimated to contribute from 15% in very clean areas to 70% in polluted areas, the contribution of nitrate is between 5% and 25% over most of Europe. This paper shows the great importance of nitrate in summer over The Netherlands.

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“…The best model is chosen by minimizing the least square error ε expressed as: This regression compares the sensor measurements ρ meas in n selected channels of the instrument, with ρ lut , the estimate of the TOA reflectance provided by the LUT data for the same wavelengths. For weakly absorbing aerosols and small optical depths [ Veefkind , 1999; Kokhanovsky et al , 2009] we can assume a linear relationship between the reflectance due to aerosols and the AOD [ Durkee et al , 1986]. Hence, if the AOD is noted as τ : The spectral values of C depend on the aerosol type.…”

Section: Algorithm Descriptionmentioning

confidence: 99%