Comparison of sea-ice freeboard distributions from aircraft data and cryosat-2

The only remote sensing technique capable of obtain- ing sea-ice thickness on basin-scale are satellite altime- ter missions, such as the 2010 launched CryoSat-2. It is equipped with a Ku-Band radar altimeter, which mea- sures the height of the ice surface above the sea level. This method requires highly accurate range measure- ments. During the CryoSat Validation Experiment (Cry- oVEx) 2011 in the Lincoln Sea, Cryosat-2 underpasses were accomplished with two aircraft, which carried an airborne laser-scanner, a radar altimeter and an electro- magnetic induction device for direct sea-ice thickness re- trieval. Both aircraft flew in close formation at the same time of a CryoSat-2 overpass. This is a study about the comparison of the sea-ice freeboard and thickness dis- tribution of airborne validation and CryoSat-2 measure- ments within the multi-year sea-ice region of the Lincoln Sea in spring, with respect to the penetration of the Ku- Band signal into the snow

Ocean-atmosphere interactions in the tropical Atlantic seasonal cycle and multidecadal variability of ENSO

The interaction between the ocean and atmosphere drives changes in the climate system in a wide variety of timescales. The strong annual cycle in the equatorial Atlantic, especially over the east, has been object of extensive research but the role of ocean-atmosphere interactions in driving the seasonal cycle remains to be fully understood in this region. The west African monsoon and the Atlantic cold tongue are the main phenomena controlling the seasonal variability in the equatorial Atlantic and a better understanding of their interaction is crucial for a complete comprehension of the dynamics of the annual cycle. Ocean atmosphere interactions are the main driver of ENSO, which is the leading mode of ocean-atmosphere variability at interannual timescales in the tropics. ENSO properties have experienced large changes in the last few decades but the drivers behind those changes are still in debate. The three studies presented in this thesis are based in climate model simulations. In the first and second papers the atmosphere and ocean components of NorESM model are used to investigate the dynamics of the seasonal cycle in the equatorial Atlantic. The third paper focuses on the identification of multidecadal modulation of ENSO properties by means of a strongly simplified model: the conceptual recharge oscillator model. The first part of this thesis presents an in-depth study of the mechanisms of the seasonal cycle in the equatorial Atlantic with special focus on the quantification of the role of the coupling between the ocean and the atmosphere. My results show that thermodynamic coupling is the main driver of the seasonal cycle in the western equatorial Atlantic and indicate that the dynamical Bjerknes feedback plays a secondary role. In the east, ocean dynamics and the monsoon are the main drivers of the seasonal cycle in the ocean and atmosphere, respectively, with ocean-atmosphere interactions contributing to the amplification of the annual cycle. In the second part of this thesis, I study the changes in observed ENSO properties at multidecadal timescales. The large observed changes in ENSO in the recent decades are reproduced with a conceptual model based on the recharge and discharge of the Pacific equatorial upper ocean heat content. This indicates that dynamic coupling is the main driver of ENSO in the last decades with the thermocline feedback being the mechanism responsible of the amplification of the SST anomalies in the eastern equatorial Pacific

Laboratory for Oceans

A review is made of the activities of the Laboratory for Oceans. The staff and the research activities are nearly evenly divided between engineering and scientific endeavors. The Laboratory contributes engineering design skills to aircraft and ground based experiments in terrestrial and atmospheric sciences in cooperation with scientists from labs in Earth sciences

NASA Oceanic Processes Program

An overview of the recent accomplishments, present activities, and future plans is provided. Sections following the introduction provides summaries of current flight projects and definition studies, brief descriptions of individual research activities, and a bibliography of referred Journal Articles appearing within the last three years

Proceedings of the NASA Symposium on Global Wind Measurements

This Proceedings contains a collection of the papers which were presented at the Symposium and Workshop on Global Wind Measurements. The objectives and agenda for the Symposium and Workshop were decided during a planning meeting held in Washington, DC, on 5 February 1985. Invited papers were presented at the Symposium by meteorologists and leading experts in wind sensing technology from the United States and Europe on: (1) the meteorological uses and requirements for wind measurements; (2) the latest developments in wind sensing technology; and (3) the status of our understanding of the atmospheric aerosol distribution. A special session was also held on the latest development in wind sensing technology by the United States Air Force

NASA Oceanic Processes Program annual review

Current flight projects and definition studies, descriptions of individual research activities, and a bibliography of referred journal articles appearing within the past two years are contained