Three-dimensional radiative transfer in midlatitude cirrus clouds
| العنوان: | Three-dimensional radiative transfer in midlatitude cirrus clouds |
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| المؤلفون: | Joanna D. Haigh, Robin J. Hogan, Wenyi Zhong |
| المصدر: | Quarterly Journal of the Royal Meteorological Society. 134:199-215 |
| بيانات النشر: | Wiley, 2008. |
| سنة النشر: | 2008 |
| مصطلحات موضوعية: | Physics, Atmospheric Science, Meteorology, Cloud top, Absorptance, Emissivity, Radiative transfer, Solar zenith angle, Cirrus, Albedo, Atmospheric sciences, Zenith |
| الوصف: | Three different types of cirrus cloud field, reconstructed in three dimensions directly from midlatitude observations by a cirrus stochastic model, are used to study the effects of three-dimensional radiative transfer in both the long-wave and short-wave spectral regions. Calculations of three-dimensional radiative transfer (3D), the independent column approximation (ICA) and the plane-parallel approximation are compared to quantify the effects on heating rates, radiative fluxes and related properties. Locally the heating rate difference between 3D and ICA reaches more than 10 K day−1 in both the long-wave and short-wave, depending upon the distributions of ice water content, which indicates that horizontal radiation transport plays an important role in structures of heating rate. The domain-averaged heating profiles of 3D agree within a few tenths of a K day−1 with ICA but show a systematic low bias. The domain-averaged heating rates in cloud layers are increased in 3D by up to 7% in the long-wave and more than 20% in the short-wave. The root-mean-square differences at individual points are up to ten times larger than the corresponding domain-averaged differences, representing the cancellation of opposing 3D effects. The ICA biases in long-wave net flux and emissivity have their maximum values (∼2–3%) near cloud top for the thinnest cloud with lowest fractional coverage. In general, ICA tends to reduce the reflected upwelling short-wave flux at the top of clouds; the layer-averaged albedo at cloud top agrees with 3D within 1%, although the corresponding RMS difference may differ by up to 30% from 3D at high solar zenith angles. Similar results are found for whole-sky (cloudy plus clear) short-wave reflectances and transmittances for which ICA agrees with 3D within 5%. For domain-averaged short-wave absorptance, however, ICA errors can reach 20%. The corresponding RMS differences may differ by up to 50% in reflectance and transmittance but exceed 200% in absorptance. The effects of solar zenith angle are also discussed. Copyright © 2007 Royal Meteorological Society |
| تدمد: | 1477-870X 0035-9009 |
| URL الوصول: | https://explore.openaire.eu/search/publication?articleId=doi_________::9504b0b39ade516e603d6715fb5aa835 https://doi.org/10.1002/qj.182 |
| حقوق: | CLOSED |
| رقم الأكسشن: | edsair.doi...........9504b0b39ade516e603d6715fb5aa835 |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 1477870X 00359009 |
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