Cloud Properties inferred from 8--12-$μ$m Data. TeX Export

@article{StrabalaEtAl1994Clds, abstract = {A trispectral combination of observations at 8-, 11-, and 12-µm bands is suggested for detecting cloud and cloud properties in the infrared. Atmospheric ice and water vapor absorption peak in opposite halves of the window region so that positive 8-minus-11-µm brightness temperature differences indicate cloud, while near-zero or negative differences indicate clear regions. The absorption coefficient for water increases more between 11 and 12 µm than between 8 and 11 µm, while for ice, the reverse is true. Cloud phase is determined by a scatter diagram of 8-minus-11-µm versus 11-minus-12-µm brightness temperature differences; ice cloud shows a slope greater than 1 and water cloud leer than 1.The trispectral brightness temperature method was tested upon high-resolution interferometer data resulting in clear-cloud and cloud-phase delineation. Simulations using differing 8-µm bandwidths revealed no significant degradation of cloud property detection. Thus, the 8-µm bandwidth for future satellites can be selected based on the requirements of other applications such as surface characterization studies. Application of the technique to current polar-orbiting High-Resolution Infrared Sounder (HIRS)-Advanced VM High Resolution Radiometer (AVHRR) datasets is constrained by the nonuniformity of the cloud scenes sensed within the large HIRS field of view.Analysis of MAS (MODIS Airborne Simulator) high-spatial resolution (500 m) data with all three 8-, 11-, and 12-µm bands revealed sharp delineation of differing cloud and background scenes from which a simple automated threshold technique was developed. Cloud phase, clear-sky, and qualitative differences in cloud emissivity and cloud height were identified on a case study segment from 24 November 1991, consistent with the scene. More rigorous techniques would allow further cloud parameter clarification.The opportunities for global cloud delineation with the Moderate-Resolution Imaging Spectrometer (MODIS) appear excellent. The spectral selection, the spatial selection, and the global coverage are all well suited for significant advances.}, author = {Strabala, K. I. and Ackerman, S. A. and Menzel, W. P.}, citeulike-article-id = {1695527}, citeulike-linkout-0 = {http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1994JApMe..33..212S}, journal = {Journal of Applied Meteorology}, keywords = {clouds, clouds-high, clouds-mask, remotesensing}, month = {February}, pages = {212--229}, posted-at = {2007-09-26 00:12:09}, priority = {2}, title = {Cloud Properties inferred from 8--12-\$\mu\$m Data.}, url = {http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1994JApMe..33..212S}, volume = {33}, year = {1994} }

TY - JOUR ID - StrabalaEtAl1994Clds L3 - citeulike-article-id:1695527 N2 - A trispectral combination of observations at 8-, 11-, and 12-µm bands is suggested for detecting cloud and cloud properties in the infrared. Atmospheric ice and water vapor absorption peak in opposite halves of the window region so that positive 8-minus-11-µm brightness temperature differences indicate cloud, while near-zero or negative differences indicate clear regions. The absorption coefficient for water increases more between 11 and 12 µm than between 8 and 11 µm, while for ice, the reverse is true. Cloud phase is determined by a scatter diagram of 8-minus-11-µm versus 11-minus-12-µm brightness temperature differences; ice cloud shows a slope greater than 1 and water cloud leer than 1.The trispectral brightness temperature method was tested upon high-resolution interferometer data resulting in clear-cloud and cloud-phase delineation. Simulations using differing 8-µm bandwidths revealed no significant degradation of cloud property detection. Thus, the 8-µm bandwidth for future satellites can be selected based on the requirements of other applications such as surface characterization studies. Application of the technique to current polar-orbiting High-Resolution Infrared Sounder (HIRS)-Advanced VM High Resolution Radiometer (AVHRR) datasets is constrained by the nonuniformity of the cloud scenes sensed within the large HIRS field of view.Analysis of MAS (MODIS Airborne Simulator) high-spatial resolution (500 m) data with all three 8-, 11-, and 12-µm bands revealed sharp delineation of differing cloud and background scenes from which a simple automated threshold technique was developed. Cloud phase, clear-sky, and qualitative differences in cloud emissivity and cloud height were identified on a case study segment from 24 November 1991, consistent with the scene. More rigorous techniques would allow further cloud parameter clarification.The opportunities for global cloud delineation with the Moderate-Resolution Imaging Spectrometer (MODIS) appear excellent. The spectral selection, the spatial selection, and the global coverage are all well suited for significant advances. JF - Journal of Applied Meteorology EP - 229 TI - Cloud Properties inferred from 8--12-$\mu$m Data. VL - 33 SP - 212 KW - clouds KW - clouds-high KW - clouds-mask KW - remotesensing AU - Strabala, KI AU - Ackerman, SA AU - Menzel, WP PY - 1994/February// UR - http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=1994JApMe..33..212S ER -