{"id":{"repo_id":"gatech","oai_identifier":"oai:repository.gatech.edu:1853/6927"},"canonical_url":"https://search.dev.ndltd.org/etd/gatech/oai:repository.gatech.edu:1853/6927","repository":{"repo_id":"gatech","name":"Georgia Tech","base_url":"https://repository.gatech.edu/server/oai/request"},"display":{"title":"Laboratory Measurements of the Millimeter Wavelength Opacity of Phosphine (PH3) and Ammonia (NH3) Under Simulated Conditions for the Cassini-Saturn Encounter","abstract":"The molecular compositions of the atmospheres of the giant planets (Jupiter, Saturn, Uranus and Neptune) are fundamental to understanding the processes which formed these planets and the solar system as a whole. Microwave observations of these planets probe regions in their atmospheres from approximately 0.1 to several bars, a process otherwise unachievable by visible and infrared means. Many gases and various cloud layers influence the millimeter wave spectra of the outer planets; however phosphine and ammonia are the main microwave absorbers at Saturn at pressures less than two bars. Understanding the pressure induced absorption of both constituents at observational frequencies is therefore vital to the analysis of any observational data. Laboratory measurements have been conducted to measure the microwave absorptivity and refractivity of phosphine and ammonia at Ka-band (32-40 GHz) and W-band (94 GHz), under conditions characteristic of the atmosphere of Saturn. The results were used to verify the accuracy of the phosphine formalism created by Hoffman et. al (2001) for use at millimeter wavelengths. Based on the laboratory measurements conducted, new formalisms were also created to express the opacity of ammonia at the measured frequencies. An important method for the study of planetary atmospheres is the radio occultation experiment ??method that uses radio links between Earth, and the spacecraft which passes behind the planet. The Cassini mission to Saturn, which will be conducting such experiments at Ka-band as well as S (2.3 GHz) and X (8.4 GHz) bands, has prompted the development of a radio occultation simulator used to calculate excess Doppler shifts and attenuation profiles for Saturn, utilizing the newest formalisms for phosphine and ammonia. The results indicate that there will be unambiguous detection and profiling of phosphine and ammonia, and predictions are made for the pressures at which loss of signal is anticipated.","abstract_html":"The molecular compositions of the atmospheres of the giant planets (Jupiter, Saturn, Uranus and Neptune) are fundamental to understanding the processes which formed these planets and the solar system as a whole. Microwave observations of these planets probe regions in their atmospheres from approximately 0.1 to several bars, a process otherwise unachievable by visible and infrared means. Many gases and various cloud layers influence the millimeter wave spectra of the outer planets; however phosphine and ammonia are the main microwave absorbers at Saturn at pressures less than two bars. Understanding the pressure induced absorption of both constituents at observational frequencies is therefore vital to the analysis of any observational data. Laboratory measurements have been conducted to measure the microwave absorptivity and refractivity of phosphine and ammonia at Ka-band (32-40 GHz) and W-band (94 GHz), under conditions characteristic of the atmosphere of Saturn. The results were used to verify the accuracy of the phosphine formalism created by Hoffman et. al (2001) for use at millimeter wavelengths. Based on the laboratory measurements conducted, new formalisms were also created to express the opacity of ammonia at the measured frequencies. An important method for the study of planetary atmospheres is the radio occultation experiment ??method that uses radio links between Earth, and the spacecraft which passes behind the planet. The Cassini mission to Saturn, which will be conducting such experiments at Ka-band as well as S (2.3 GHz) and X (8.4 GHz) bands, has prompted the development of a radio occultation simulator used to calculate excess Doppler shifts and attenuation profiles for Saturn, utilizing the newest formalisms for phosphine and ammonia. The results indicate that there will be unambiguous detection and profiling of phosphine and ammonia, and predictions are made for the pressures at which loss of signal is anticipated.","abstract_has_math":false,"creators":["Mohammed, Priscilla Naseem"],"institution":"Georgia Institute of Technology","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":"Electrical and Computer Engineering","school":null,"contributors":[],"advisors":["Steffes, Paul G."],"committee_chairs":[],"committee_members":["Aaron Lanterman","Andrew F. Peterson","Judith A. Curry","Waymond R. Scott"],"year":2005,"date_issued":"2005-04-18","date_published":"2005-04-18","updated_at":"2026-07-27T19:50:24Z","subjects":["Microwave remote sensing","Radio occultation","Millimeter wave measurements"],"languages":["en_US"],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/1853/6927","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Steffes, Paul G."]},{"key":"dc:contributor.committeemember","label":"Committee Member","values":["Aaron Lanterman","Andrew F. Peterson","Judith A. Curry","Waymond R. Scott"]},{"key":"dc:contributor.department","label":"Department","values":["Electrical and Computer Engineering"]},{"key":"dc:creator","label":"Author","values":["Mohammed, Priscilla Naseem"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2005-07-28T18:02:10Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2005-07-28T18:02:10Z"]},{"key":"dc:date.issued","label":"Date","values":["2005-04-18"]},{"key":"dc:publisher","label":"Institution","values":["Georgia Institute of Technology"]},{"key":"dc:type","label":"Dc Type","values":["Text"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Microwave remote sensing","Radio occultation","Millimeter wave measurements"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["en_US"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/1853/6927"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["The molecular compositions of the atmospheres of the giant planets (Jupiter, Saturn, Uranus and Neptune) are fundamental to understanding the processes which formed these planets and the solar system as a whole. Microwave observations of these planets probe regions in their atmospheres from approximately 0.1 to several bars, a process otherwise unachievable by visible and infrared means. Many gases and various cloud layers influence the millimeter wave spectra of the outer planets; however phosphine and ammonia are the main microwave absorbers at Saturn at pressures less than two bars. Understanding the pressure induced absorption of both constituents at observational frequencies is therefore vital to the analysis of any observational data. Laboratory measurements have been conducted to measure the microwave absorptivity and refractivity of phosphine and ammonia at Ka-band (32-40 GHz) and W-band (94 GHz), under conditions characteristic of the atmosphere of Saturn. The results were used to verify the accuracy of the phosphine formalism created by Hoffman et. al (2001) for use at millimeter wavelengths. Based on the laboratory measurements conducted, new formalisms were also created to express the opacity of ammonia at the measured frequencies. An important method for the study of planetary atmospheres is the radio occultation experiment ??method that uses radio links between Earth, and the spacecraft which passes behind the planet. The Cassini mission to Saturn, which will be conducting such experiments at Ka-band as well as S (2.3 GHz) and X (8.4 GHz) bands, has prompted the development of a radio occultation simulator used to calculate excess Doppler shifts and attenuation profiles for Saturn, utilizing the newest formalisms for phosphine and ammonia. The results indicate that there will be unambiguous detection and profiling of phosphine and ammonia, and predictions are made for the pressures at which loss of signal is anticipated."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Ph.D."]},{"key":"dc:format.mimetype","label":"Dc Format Mimetype","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Laboratory Measurements of the Millimeter Wavelength Opacity of Phosphine (PH3) and Ammonia (NH3) Under Simulated Conditions for the Cassini-Saturn Encounter"]}]}],"canonical_facts":{"dc:contributor.advisor":["Steffes, Paul G."],"dc:contributor.committeemember":["Aaron Lanterman","Andrew F. Peterson","Judith A. Curry","Waymond R. Scott"],"dc:contributor.department":["Electrical and Computer Engineering"],"dc:creator":["Mohammed, Priscilla Naseem"],"dc:date.accessioned":["2005-07-28T18:02:10Z"],"dc:date.available":["2005-07-28T18:02:10Z"],"dc:date.issued":["2005-04-18"],"dc:description.abstract":["The molecular compositions of the atmospheres of the giant planets (Jupiter, Saturn, Uranus and Neptune) are fundamental to understanding the processes which formed these planets and the solar system as a whole. Microwave observations of these planets probe regions in their atmospheres from approximately 0.1 to several bars, a process otherwise unachievable by visible and infrared means. Many gases and various cloud layers influence the millimeter wave spectra of the outer planets; however phosphine and ammonia are the main microwave absorbers at Saturn at pressures less than two bars. Understanding the pressure induced absorption of both constituents at observational frequencies is therefore vital to the analysis of any observational data. Laboratory measurements have been conducted to measure the microwave absorptivity and refractivity of phosphine and ammonia at Ka-band (32-40 GHz) and W-band (94 GHz), under conditions characteristic of the atmosphere of Saturn. The results were used to verify the accuracy of the phosphine formalism created by Hoffman et. al (2001) for use at millimeter wavelengths. Based on the laboratory measurements conducted, new formalisms were also created to express the opacity of ammonia at the measured frequencies. An important method for the study of planetary atmospheres is the radio occultation experiment ??method that uses radio links between Earth, and the spacecraft which passes behind the planet. The Cassini mission to Saturn, which will be conducting such experiments at Ka-band as well as S (2.3 GHz) and X (8.4 GHz) bands, has prompted the development of a radio occultation simulator used to calculate excess Doppler shifts and attenuation profiles for Saturn, utilizing the newest formalisms for phosphine and ammonia. The results indicate that there will be unambiguous detection and profiling of phosphine and ammonia, and predictions are made for the pressures at which loss of signal is anticipated."],"dc:description.degree":["Ph.D."],"dc:format.mimetype":["application/pdf"],"dc:identifier.uri":["http://hdl.handle.net/1853/6927"],"dc:language.iso":["en_US"],"dc:publisher":["Georgia Institute of Technology"],"dc:subject":["Microwave remote sensing","Radio occultation","Millimeter wave measurements"],"dc:title":["Laboratory Measurements of the Millimeter Wavelength Opacity of Phosphine (PH3) and Ammonia (NH3) Under Simulated Conditions for the Cassini-Saturn Encounter"],"dc:type":["Text"]},"updated_at":"2026-07-27T19:50:24Z"}