Numerical Model Studies of the Martian Mesoscale Circulations

The study objectives were to evaluate by numerical modeling various possible mesoscale circulation on Mars and related atmospheric boundary layer processes. The study was in collaboration with J. Tillman of the University of Washington (who supported the study observationally). Interaction has been made with J. Prusa of Iowa State University in numerical modeling investigation of dynamical effects of topographically-influenced flow. Modeling simulations included evaluations of surface physical characteristics on: (i) the Martian atmospheric boundary layer and (ii) their impact on thermally and dynamically forced mesoscale flows. Special model evaluations were made in support of selection of the Pathfinder landing sites. J. Tillman's finding of VL-2 inter-annual temperature difference was followed by model simulations attempting to point out the forcing for this feature. Publication of the results in the reviewed literature in pending upon completion of the manuscripts in preparation as indicated later

Changes in extreme, cold-season synoptic precipitation events under global warming

We analyze regional climate model (RCM) simulations of daily, spatially distributed extreme precipitation events, using co-operative network observations and output from 10-year RCM simulations of present and future-scenario climates. We examine an Upper Mississippi River Basin region during October–March for daily amounts that exceed the 99.95th percentile and that occur simultaneously at several observation sites or model grid points. For the observations and each simulation, nearly all such extreme regional events occur when a slow moving, cut-off-low system develops over the Rockies and Great Plains and steadily pumps moisture into the Upper Mississippi region from the Gulf of Mexico. The threshold for the extreme events increases in the future scenario by an amount similar to the increase in saturation specific humidity. The results suggest robust circulation behavior for such extremes in the face of climate change

Wind speed trends over the contiguous United States

A comprehensive intercomparison of historical wind speed trends over the contiguous United States is presented based on two observational data sets, four reanalysis data sets, and output from two regional climate models (RCMs). This research thus contributes to detection, quantification, and attribution of temporal trends in wind speeds within the historical/contemporary climate and provides an evaluation of the RCMs being used to develop future wind speed scenarios. Under the assumption that changes in wind climates are partly driven by variability and evolution of the global climate system, such changes should be manifest in direct observations, reanalysis products, and RCMs. However, there are substantial differences in temporal trends derived from observational wind speed data, reanalysis products, and RCMs. The two observational data sets both exhibit an overwhelming dominance of trends toward declining values of the 50th and 90th percentile and annual mean wind speeds, which is also the case for simulations conducted using MM5 with NCEP-2 boundary conditions. However, converse trends are seen in output from the North American Regional Reanalysis, other global reanalyses (NCEP-1 and ERA-40), and the Regional Spectral Model. Equally, the relationship between changing annual mean wind speed and interannual variability is not consistent among the different data sets. NCEP-1 and NARR exhibit some tendency toward declining (increasing) annual mean wind speeds being associated with decreased (increased) interannual variability, but this is not the case for the other data sets considered. Possible causes of the differences in temporal trends from the eight data sources analyzed are provided

Putting into action the REGCM4.6 regional climate model for the study of climate change, variability and modeling over Central America and Mexico

What: International experts and attendees from several countries of Central America, Mexico, the Caribbean (CAM), and South America (SA) met to discuss regional issues on climate variability and climate change to learn the use of the non-hydrostatic version of the International Center for Theoretical Physics (ICTP) RegCM4.6 model, and to establish a regional modeling scientific community for understanding the physics of climate processes and the generation of regional climate change scenarios. When: 14-18 November 2016. Where: Center for Geophysical Research (CIGEFI in Spanish) and School of Physics, University of Costa Rica (UCR), San José, Costa Rica.Ministerio de Ciencia, Tecnología y Telecomunicaciones/[FI-0015-16]/MICITT/Costa RicaUniversidad de Costa Rica/[805-B0-065]/UCR/Costa RicaUniversidad de Costa Rica/[805-A8-606]/UCR/Costa RicaUniversidad de Costa Rica/[805-B0-130]/UCR/Costa RicaUniversidad de Costa Rica/[805-A9-224]/UCR/Costa RicaUniversidad de Costa Rica/[805-A7-002]/UCR/Costa RicaUniversidad de Costa Rica/[805-B0-402]/UCR/Costa RicaUniversidad de Costa Rica/[805-B3-600]/UCR/Costa RicaUniversidad de Costa Rica/[805-B4-227]/UCR/Costa RicaUniversidad de Costa Rica/[805-B5-296]/UCR/Costa RicaUniversidad de Costa Rica/[808-A9-180]/UCR/Costa RicaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigaciones Geofísicas (CIGEFI