کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5428729 1508694 2013 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Statistical analysis of single-track instrument sampling in spaceborne aerosol remote sensing for climate research
ترجمه فارسی عنوان
تجزیه و تحلیل آماری نمونه برداری یک طرفه در سنجش از دور با استفاده از فضاپیمای آئروسل برای تحقیقات آب و هوایی
کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه شیمی طیف سنجی
چکیده انگلیسی

We examine likely effects of pixel-wide along-track sampling on climatological means of aerosol optical thickness (AOT) derived from observations with satellite instruments such as CALIOP and APS by sub-sampling AOT retrievals from a wide-swath imaging instrument (MODIS). The advantage of using daily pixel-level aerosol retrievals from MODIS rather than aerosol transport models to assess the results of along-track sampling is that limitations caused by the presence of clouds are implicit in the satellite dataset, so that their seasonal and regional variations are captured coherently. However, imager data can exhibit latitudinal (cross-track) variability of monthly global mean AOTs caused by a scattering-angle dependence. This makes it difficult to separate natural variability from viewing-geometry artifacts complicating direct comparisons of an along-track sub-sample with the full imager data. To work around this problem, we introduce “latitudinal-track” sampling which, by design, captures the cross-track AOT variability of the original imager data. We show that the latitudinal-track standard error of global monthly mean AOTs is much smaller than the longitudinal-track one. This allows us to attribute the difference between the two errors to MODIS viewing-geometry artifacts and obtain an upper limit on AOT errors caused by along-track sampling. We conclude that single-track instruments provide AOT sampling sufficient for climate applications. Since AOT is believed to be the most variable characteristic of tropospheric aerosols, our results imply that pixel-wide along-track coverage also provides adequate statistical representation of the global distribution of aerosol microphysical parameters.

► Imager aerosol data used to study effects of along-track sampling for climate research. ► Viewing artifacts complicate comparisons of longitudinal-track sub-sample with imager data. ► Latitudinal-track sampling separates natural aerosol variability from viewing artifacts. ► Latitudinal-track standard error of mean AOT is much smaller than the cross-track one. ► Single-track instruments provide aerosol sampling sufficient for climate applications.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Quantitative Spectroscopy and Radiative Transfer - Volume 121, May 2013, Pages 69-77
نویسندگان
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