BEGIN:VCALENDAR VERSION:2.0 PRODID:-//132.216.98.100//NONSGML kigkonsult.se iCalcreator 2.20.4// BEGIN:VEVENT UID:20250824T010348EDT-2230dUk3kw@132.216.98.100 DTSTAMP:20250824T050348Z DESCRIPTION:Cloud-assisted retrieval of stratospheric water vapor from nadi r view satellite measurements\n\n Water vapor in dry atmospheric environmen ts is of great importance for weather and climate. For example\, despite o f its scarcity\, stratospheric water vapor is an important atmospheric com ponent that can greatly influence climate change\, due to its radiative an d chemical impacts. Recent studies suggest that stratospheric water vapor may have strong relations to surface climate change and stratospheric ozon e loss\, highlighting the need of improved monitoring of stratospheric wat er vapor. However\, the retrieval of stratospheric water vapor is known to be challenging. Satellite nadir view radiance measurements usually do not have sufficient sensitivity to the low concentration of stratospheric wat er vapor while limb view measurements have large sampling footprints\, mak ing small scale water vapor hard to be detected.\n\n This study tests the f easibility of retrieving the stratospheric water vapor in the presence of dense upper tropospheric clouds\, which block the radiance emission and ob scuration of the lower atmosphere for stratospheric retrieval. This invest igation uses synthetic satellite radiance simulated from atmospheric profi les using a radiative transfer model\, MODTRAN\, and adopts a widely-used optimal estimation method [Rodgers 2000] that iteratively retrieve the str atospheric temperature and humidity.\n\n We find the quality of retrieval r esults depends on several factors. High spectral resolution and low level of measurement noise are especially beneficial to the retrieval accuracy\, while the coverage of far infrared band is also critical. An ideal case i s able to effectively reduce 44% uncertainty for specific humidity\, and i mprove 55% of accuracy for column integrated water vapor in the lower stra tosphere. \n\n DTSTART:20161019T183000Z DTEND:20161019T193000Z LOCATION:Room 934\, Burnside Hall\, CA\, QC\, Montreal\, H3A 0B9\, 805 rue Sherbrooke Ouest SUMMARY:Student Seminar: Jing Feng URL:/meteo/channels/event/student-seminar-jing-feng-26 2517 END:VEVENT END:VCALENDAR