Meteorology Commons^™

Sensitivity Of Conus Summer Rainfall To The Selection Of Cumulus Parameterization Schemes In Nu-Wrf Seasonal Simulations, Takamichi Iguchi, Wei-Kuo Tao, Di Wu, Christa D. Peters-Lidard, Joseph A. Santanello, Eric Kemp, Yudong Tian, Jonathan Case, Weile Wang, Robert Ferraro, Duane E. Waliser, Jinwon Kim, Huikyo Lee, Bin Guan, Baijun Tian, Paul C. Loikith

Geography Faculty Publications and Presentations

This study investigates the sensitivity of daily rainfall rates in regional seasonal simulations over the contiguous United States (CONUS) to different cumulus parameterization schemes. Daily rainfall fields were simulated at 24-km resolution using the NASA-Unified Weather Research and Forecasting (NU-WRF) Model for June–August 2000. Four cumulus parameterization schemes and two options for shallow cumulus components in a specific scheme were tested. The spread in the domain-mean rainfall rates across the parameterization schemes was generally consistent between the entire CONUS and most subregions. The selection of the shallow cumulus component in a specific scheme had more impact than that of the …

Cirrus Cloud Microphysics Over Darwin, Australia, Dorothea Ivanova, Matthew Johnson

Publications

Ice clouds, crucial to the understanding of both short - and long - term climate trends, are poorly represented in global climate models (GCMs). Cirrus clouds, one of the largest uncertainties in the global radiation budget, have been inadequately studied at low latitudes. Parameterizations exist for mid - latitude and tropical cirrus ( Ivanova et al. 2001; McFarquhar et al. 1997). Due to climate sensitivity in the GCM with respect to cloud input, without robust parameterizations of cirrus clouds, the GCM is inaccurate over most output fields, including radiative forcing, temperature, albedo, and heat flux (Yao and Del Genio 1999). …

Determination And Analysis Of Dscovr-Eipc Satellite-Retrieved Radiance From Cloud Geometric And Optical Properties, Emily Christine Morgan

Legacy Theses & Dissertations (2009 - 2024)

Using simulations and numerical fitting, this work sought to describe the satellite-retrieved radiance of clouds as a function of their thermodynamic and optical properties. Subsequently, this understanding can then be used in a look-up-table to determine the properties of clouds imaged by the EPIC sensor in the NASA DSCOVR satellite. In this study, background oxygen absorption was modeled in a radiative transfer model and convolved with EPIC filter functions for two absorption-reference pairs for Oxygen A- and B-band. This absorption profile was established as the primary vertical coordinate in this study, leveraging the similarity principle to allow for intercomparison of …

Characterization Of Tropical Clouds Using Multi-Satellite Observations, Ricardo Anderson

Dissertations and Theses

Clouds an important component of the earth-climate system and play a critical role in affecting energy and water cycle of the planet. In particular, tropical convective clouds account for the majority of the precipitation that fall on the Earth's surface. Multiple active satellite missions in recent decade such as TRMM (Tropical Rainfall Measurement Mission), and CloudSat have provided fruitful new insight into the internal structures of these tropical convective clouds. In conjunction with cloud data from ISCCP (International Satellite Cloud Climatology Project), that is based passive remote sensing technology in the visible and infrared spectrum, this allows for a more …

Research Poster: An Overview Of Progress In Nsf Epscor Project Entitled, “Reducing Cloud Uncertainties In Climate Models”, Subhashree Mishra, David L. Mitchell, W. Patrick Arnott

2010 Annual Nevada NSF EPSCoR Climate Change Conference

Research poster

Evolution Of Cloud-To-Ground Lightning Discharges In Tornadic Thunderstorms, Wendy L. Seaman

Theses and Dissertations

Air Force operations are directly impacted by weather on a daily basis. Erroneous forecasts negatively impact mission readiness and consequently cost the government time, in terms of wasted man-hours, and money. Advanced forecast lead-time could make a difference to minimize loss to both USAF personnel and assets. This study examined lightning data from 64 storm events from 1995-2000 in search of unique lightning signatures indicative of tornadic activity. Overall flash rates, percentage of positive flashes, positive and negative peak currents and multiplicity for each case were separated into two categories based on tornado intensity and season of occurrence. Based on …

Development Of Predictors For Cloud-To-Ground Lightning Activity Using Atmospheric Stability Indices, Kenneth C. Venzke

Theses and Dissertations

A detailed examination was performed on several commonly applied atmospheric stability indices and lightning activity from 1993 to 2000 to determine the indices usefulness as predictive tools for determining cloud-to-ground lightning activity. Predetermined radii of 50 nautical miles around upper-air stations in the Midwest U.S. were used for the lightning summaries. Also explored is an improvement upon the commonly accepted thresholds of the stability indices as general thunderstorm indicators. An improvement was found and new threshold ranges were developed for relating stability index values to lightning occurrence. Traditional statistical regression methods failed to find a significant predictive relationship. By examining …

Experimental Goes Sounder Products For The Assessment Of Downburst Potential, Gary P. Ellrod, James P. Nelson Iii, Michael R. Witiw, Lynda Bottos, William P. Roeder

Aeronautics Faculty Publications

Several experimental products derived from Geostationary Operational Environmental Satellite (GOES) Sounder retrievals (vertical profiles of temperature and moisture) have been developed to assist weather forecasters in assessing the potential for convective downbursts. The product suite currently includes the wind index (WINDEX), a dry microburst index, and the maximum difference in equivalent potential temperature (θe) from the surface to 300 hPa. The products are displayed as color-coded boxes or numerical values, superimposed on GOES visible, infrared, or water vapor imagery, and are available hourly, day and night, via the Internet. After two full summers of evaluation, the products have been shown …

A Validation Study Of The Ssm/I Temperature Algorithm And Comparison With The Cal/Val Land Surface Temperatures, Ronald L. Comoglio

Theses and Dissertations

The USAF operational cloud model, the Real-Time Nephanalysis (RTNEPH), requires infrared and visual scene scans as well as input from the Special Sensor Microwave Imager (SSM/I), featured on the Defense Meteorological Satellite Program (DMSP) polar orbiters. Additionally, SSM/I provides input to the Air Force Global Weather Center (AFGWC) surface temperature model (SFCTMP). The global surface temperatures are required for identifying which pixel of a scene is cloud and which is ground and as a first guess input to initialize NWP models. The SSM/I provides brightness temperatures sampled at four discrete: frequencies and dual polarizations to produce surface temperatures. Two algorithms …

An Alternative Representation Of The Ice Canopy For Calculating Microwave Brightness Temperatures Over A Thunderstorm, Bradley M. Muller, Henry E. Fuelberg, Eric A. Smith

Publications

Passive microwave brightness temperatures (T(B)'s) at 92 and 183 GHz from an aircraft thunderstorm overflight are compared with values calculated from radar-derived hydrometeor profiles and a modified proximity sounding. Two methods for modeling particles in the ice canopy are contrasted. The first is a ''traditional'' approach employing Marshall-Palmer ice spheres. The second, or ''alternative,'' method partitions 20% of the ice water content into a Marshall-Palmer component for graupel and hail, and 80% into a modified gamma spherical particle size distribution function representing ice crystals.

Results from the alternative approach are superior to those from the traditional method in the anvil …