Graduate Student Visitor Program 2008 Awards

Kathrin Häusler Home Institution: GeoForshungsZentrum Potsdam   NCAR Host Division: High Altitude Observatory (HAO) in the Earth and Sun Systems Laboratory (ESSL)   Purpose of visit:   Recent observations performed by the CHAMP (CHAllenging Minisatellite Payload) satellite revealed that there exists a four-peaked longitudinal variation in the zonal component of the thermospheric wind at 400 km altitude. This so far unexpected feature seems to be related to the eastward propagating non-migrating diurnal tide with wavenumber 3 (DE3). The DE3 tide is primarily excited by latent heat release resulting from deep tropical convection in the troposphere. Thus this first study of zonal wind longitudinal dependences provides new observational evidence for the coupling of the various atmospheric layers.   The purpose of the visit is to investigate in more detail the relation between the longitudinal variation of the thermospheric zonal wind and the predicted DE3 excitation. For this task the self consistent Thermosphere-Ionosphere Mesosphere Electrodynamics General Circulation Model (TIME-GCM) will be used. At the lower boundary of TIME-GCM migrating and non-migrating tides as calculated by the Global Scale Wave Model (GSWM) are specified. We will study the zonal neutral winds signature at the equator of TIME-GCM, compare the results with CHAMP data, and investigate possible causes of the signature.   Collaborator(s): Astrid Maute   Length of Stay: 3 Months   Advisor: Hermann Lühr   Irina Herdlinger Home Institution: University of Innsbruck, Austria   NCAR Host Divisions: The Institute for Integrative and Multidisciplinary Earth Studies (TIIMES) in the Earth and Sun Systems Laboratory (ESSL)   Purpose of visit:   During Herdlinger's visit she will conduct independent field and laboratory work, investigating environmental controls over biogenic volatile organic compound (VOC) emissions and how climate change can influence emission patterns of VOCs. (Thesis Title: Investigation of environmental parameters driving the emissions of volatile organic compounds from coniferous trees using chemical ionization mass spectrometry.)   Collaborator(s): Thomas Karl   Length of Stay: 1 Year   Advisor: Dr. Armin Wisthaler   Cameron Homeyer Home Institution: Texas A&M University   NCAR Host Division: The Institute for Integrative and Multidisciplinary Earth Studies (TIIMES) in the Earth and Sun Systems Laboratory (ESSL)   Purpose of visit:   NCAR UTLS initiative, in collaboration with university community, is leading a field campaign, Stratosphere-Troposphere Analyses of Regional Transport in spring 2008 (START08), using the HIAPER in the Spring of 2008. This visit will occur during and after the field campaign. Both the student’s host Laura Pan and his thesis advisor Kenneth Bowman are lead investigators of the field campaign. One of the main purposes for this visit is to train graduate students and post-doctoral scientists in both field campaign observations and data analysis done collaboratively with modelers and other science team members. The student visitor will focus on analyzing various measurement from HIAPER obtained from the START08 to examine the characteristics of chemical transport in the extratropical upper tropospheric and lower stratospheric (ExUTLS) regions.   Collaborator(s): Laura Pan   Length of Stay: 3 Months   Advisor: Kenneth P. Bowman   Tara Hudiburg Home Institution: Oregon State University   NCAR Host Division: Climate and Global Dynamics Division (CGD) in the Earth and Sun Systems Laboratory (ESSL)   Purpose of visit:   The purpose of this visit will be to acquire the skills and knowledge necessary to model the interactive effects of several factors using Biome-BGC and the land model component of the NCAR CCSM that includes the Biome-BGC treatment of coupled carbon and nitrogen cycles (CLM-CN). Modification of model structure will be required as part of the experiments. I am leading the working group responsible for development and implementation of the terrestrial carbon and nitrogen processes in the global coupled climate system model, therefore changes to the code need to be done under my direct supervision.   Collaborator(s): Peter Thornton   Length of Stay: 3 Months   Advisor: Beverly Law   Dorota Jareka Home Institution: University of Warsaw   NCAR Host Division: Mesoscale & Microscale Meteorology Division (MMM) in the Earth and Sun Systems Laboratory (ESSL)   Purpose of visit:   Dorota will stay at NCAR for 6 months (February-August 2008), supported jointly by ASP, GTP, and Grabowski's NOAA grant. She will participate in GTP/IMAGE Theme Of the Year workshop in spring 2008. She will perform model simulations of stratocumulus-topped boundary layer with the emphasis on microphysical transformations during entrainment and mixing. She will learn details of the model and benefit from interactions with her co-adviser (Grabowski) as well as with MMM's Hugh Morrison.   Collaborator(s): Wojciech Grabowski   Length of Stay: 3 Months   Advisor: Hanna Pawlowska and Wojciech Grabowski   Umamaheswara Konda-Venkata Umamaheswara Konda-Venkata and Paul Bieringer Home Institution: University at Buffalo   NCAR Host Division: Research Applications Laboratory (RAL)   Purpose of visit:   The student will work with scientists in RAL on problems related to the characterization of sources of hazardous material released into the atmosphere. Such good source estimation is mandatory for high fidelity forecasting of plumes in a dispersion process. Forward and backward modeling methods have traditionally been used for estimating the source location and strength. The backward modeling approach requires the adjoint model, and the forward modeling approach can lead to local minima in the source estimation optimization problem. There is thus a need to develop techniques which can generate globally optimal solutions. Techniques such as simulated annealing and genetic algorithms can potentially address the aforementioned source identification problem. The purpose of the visit is to explore the use of simulated annealing for identifying source characteristics. The use of simulated annealing in conjunction with adjoint methods will also be explored   Collaborator(s): Paul Bieringer   Length of Stay: 3 Months   Advisors: Tarunraj Singh   Matthew Norman Home Institution: North Carolina State University   NCAR Host Division: Institute for Mathematics Applied to Geosciences (IMAGe) in the Computational and Information Systems Laboratory (CISL)   Purpose of visit:   Matt is developing various central and upwind Godunov-type finite volume methods applied to the atmospheric dynamical equations with emphasis on the treatment of multi-dimensionality and the various approximations used to describe sub-gridscale variation for high-order accuracy. Choice methods will be implemented in a global shallow water model and / or a 2-D fully compressible model for more realistic evaluation.   Collaborator(s): Ram Nair   Length of Stay: 9 Months   Advisor: Fredrick Semazzi   Jonathan Smith Home Institution: Howard University   NCAR Host Division: Atmospheric Chemistry Division (ACD) in the Earth and Sun Systems Laboratory (ESSL)   Purpose of visit:   Our goal is simulate the roles of natural versus anthropogenic sources of ozone and ozone precursor transport (horizontal and vertical) in mesoscale convective systems using the WRF chem.. The area of focus is west and central Africa. Dr. Mary Barth’s team is developing a lightning-NOx parameterization which will be tested in WRF chem.. Moreover, global inventory emissions must be used for initial/boundary conditions when using WRF-CHEM over Africa and implemented during the visit.   Collaborator(s): Mary Barth   Length of Stay: 3 Months   Advisor: Dr. Gregory S. Jenkins   Qiong Yang Home Institution: University of Washington   NCAR Host Division: Climate and Global Dynamics Division (CGD) in the Earth and Sun Systems Laboratory (ESSL)   Purpose of visit:   The visit will be used for Qiong to get more familiar with the details and operation of the NCAR Community Atmosphere Model, and to work closely with model developers to help understand and diagnose the physical processes in the Tropical Tropopause Layer and the tropical lower stratosphere in both WACCM and CAM. Qiong will work with NCAR scientists and postdocs in the Climate Modeling Section of CGD and WACCM group in ACD.   Collaborator(s): Andrew Gettelman   Length of Stay: 3 Months   Advisor: Qiang Fu