Atmospheric Sciences Commons^™

Chilean Coastal Orographic Precipitation Experiment : A Tale Of Two Rain Regimes, Adam Massmann

Legacy Theses & Dissertations (2009 - 2024)

The Chilean Coastal Orographic Precipitation Experiment Pilot Project (CCOPE-2015) was an exploratory field campaign to better understand the mechanisms of orographic precipitation enhancement in the Nahuelbuta Mountains of Southern Chile (38 deg. S.). Observations collected include: (1) surface rainfall from a network of 10 data logging rain gauges, (2) vertical precipitation profiles from a pair of K-band Micro Rain Radars, (3) rain drop size distributions from an optical disdrometer, (4) upstream wind and thermodynamic profiles from radiosonde launches, and (5) aerosol number concentration and size distribution measurements from a condensation particle counter and an ultra-high sensitivity aerosol spectrometer.

Hydroclimate Changes In The South-Central Great Plains Of The United States : A Synoptic Approach, Pawel Slaski

Legacy Theses & Dissertations (2009 - 2024)

Hydroclimate changes over the Southern Central Great Plains (SCGP) of the United States have been occurring throughout the last century. These changes have had a major impact on the local ecosystems, agriculture, and human society in the region by, e.g., producing a higher frequency of drought over the last century. Climate models project further increases of drought in the 21st century over this region under increasing greenhouse gases. This study analyzes climate model simulations to examine changes in synoptic conditions associated with the projected drought increases over the SCGP. Synoptically, mesoscale convective complexes (MCCs) produce a large portion of the …

The Network Average Gust Factor, Its Measurement And Environmental Controls, And Role In Gust Forecasting, Alexander Austin Gallagher

Legacy Theses & Dissertations (2009 - 2024)

There exists a strong, well documented linear relationship between network averaged sustained (or mean) wind and gust speeds within the San Diego Gas and Electric (SDGE) mesonet that is characterized by the slope of the linear regression between the two known as the network average gust factor (GF). The network average GF potentially contains information on the average obstruction of the stations within the network and when paired with numerical model output, may be used for gust prediction. Using the network average GF for gust prediction can also result in the correction of biases due to poorly resolved terrain or …

Droughtscape, Winter 2016, Kelly Smith

DroughtScape: Quarterly Newsletter of the National Drought Mitigation Center (2007–2023)

Contents

Director’s column

California drought FAQ

October-December 2015 drought

October-December 2015 impacts

2015 drought impacts in review

NDMC hiring geospatial analyst

CA drought exposes social vulnerability

UA helps Arizona ranchers, Forest Service work together

NDMC and partners help southern Plains ranchers manage drought

Chickasaw ranching workshop

Global Stratospheric Measurements Of The Isotopologues Of Methane From The Atmospheric Chemistry Experiment Fourier Transform Spectrometer, Eric M. Buzan, Chris A. Beale, Chris. D. Boone, Peter F. Bernath

Chemistry & Biochemistry Faculty Publications

This paper presents an analysis of observations of methane and its two major isotopologues, CH₃D and ¹³CH₄, from the Atmospheric Chemistry Experiment (ACE) satellite between 2004 and 2013. Additionally, atmospheric methane chemistry is modeled using the Whole Atmospheric Community Climate Model (WACCM). ACE retrievals of methane extend from 6 km for all isotopologues to 75 km for ¹²CH₄, 35 km for CH₃D, and 50 km for ¹³CH₄. While total methane concentrations retrieved from ACE agree well with the model, values of δD-CH₄ and δ¹³C-CH …

Detailed Source-Specific Molecular Composition Of Ambient Aerosol Organic Matter Using Ultrahigh Resolution Mass Spectrometry And H Nmr, Amanda S. Willoughby, Andrew S. Wozniak, Patrick G. Hatcher

Chemistry & Biochemistry Faculty Publications

Organic aerosols (OA) are universally regarded as an important component of the atmosphere that have far-ranging impacts on climate forcing and human health. Many of these impacts are related to OA molecular characteristics. Despite the acknowledged importance, current uncertainties related to the source apportionment of molecular properties and environmental impacts make it difficult to confidently predict the net impacts of OA. Here we evaluate the specific molecular compounds as well as bulk structural properties of total suspended particulates in ambient OA collected from key emission sources (marine, biomass burning, and urban) using ultrahigh resolution mass spectrometry (UHR-MS) and proton nuclear …

Upper Tropospheric Water Vapour Variability At High Latitudes- Part 1: Influence Of The Annular Modes, Christopher E. Sioris, Jason Zou, David A. Plummer, Chris D. Boone, C. Thomas Mcelroy, Patrick E. Sheese, Omid Moeini, Peter F. Bernath

Chemistry & Biochemistry Faculty Publications

Seasonal and monthly zonal medians of water vapour in the upper troposphere and lower stratosphere (UTLS) are calculated for both Atmospheric Chemistry Experiment (ACE) instruments for the northern and southern high-latitude regions (60-90° N and 60-90°S). Chosen for the purpose of observing high-latitude processes, the ACE orbit provides sampling of both regions in 8 of 12 months of the year, with coverage in all seasons. The ACE water vapour sensors, namely MAESTRO (Measurements of Aerosol Extinction in the Stratosphere and Troposphere Retrieved by Occultation) and the Fourier Transform Spectrometer (ACE-FTS) are currently the only satellite instruments that can probe from …

Mipas Imk/Iaa Cfc-11 (Ccl3f) And Cfc-12 (Ccl2f2) Measurements: Accuracy, Precision And Long-Term Stability, E. Eckert, A. Laeng, S. Lossow, S. Kellmann, G. Stiller, T. Von Clarmann, N. Glatthor, M. Hopfner, M. Kiefer, H. Oelhaf, P. F. Bernath

Chemistry & Biochemistry Faculty Publications

Profiles of CFC-11 (CCl₃F) and CFC-12 (CCl₂F₂) of the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) aboard the European satellite Envisat have been retrieved from versions MIPAS/4.61 to MI-PAS/4.62 and MIPAS/5.02 to MIPAS/5.06 level-1b data using the scientific level-2 processor run by Karlsruhe Institute of Technology (KIT), Institute of Meteorology and Climate Research (IMK) and Consejo Superior de Investigaciones Cientificas (CSIC), Instituto de Astrofisica de Andalucia (IAA). These profiles have been compared to measurements taken by the balloon-borne cryosampler, Mark IV (MkIV) and MIPAS-Balloon (MIPAS-B), the airborne MIPAS-STRatospheric aircraft (MIPAS-STR), the satellite-borne Atmospheric Chemistry …

Regional Variations Of Optimal Sowing Dates Of Maize For The Southwestern U.S., Boksoon Myoung, Seung Hee Kim, Jinwon Kim, Menas Kafatos

Mathematics, Physics, and Computer Science Faculty Articles and Research

Sowing date (SD) is sensitive to regional climate characteristics; thus, it is critical to systematically examine the effects of SD on crop yields for various temperature regimes. We performed a sensitivity study of SD for maize in the southwestern U.S. using the regionally extended version of the Agricultural Production Systems sIMulator (APSIM) model. The model was run utilizing North American Regional Reanalysis at a 32 km resolution from 1991 to 2011, with an irrigation threshold at 95% of the soil water-holding capacity. Two types of SD optimizations maximizing yield potential (Yp), varying spatially or interannually, revealed that the optimal SD …

Sensitivity Of Maize Yield Potential To Regional Climate In The Southwestern U.S., Seung Hee Kim, Boksoon Myoung, David Stack, Jinwon Kim, Menas Kafatos

Mathematics, Physics, and Computer Science Faculty Articles and Research

The sensitivity of maize yields to the regional climate in the Southwestern U.S. (SWUS) has been investigated by using the Agricultural Production Systems sIMulator (APSIM) model in conjunction with meteorological forcings [daily maximum and minimum temperature (Tmax and Tmin), precipitation, and radiation] from the North American Regional Reanalysis (NARR) dataset. Sensitivity experiments showed that potential crop production responded nonlinearly to variations in Tmax, Tmin, and downwelling solar radiation at the surface. Mean annual yield potential (Yp) was changed by -3.0 and 1.79 Mg ha-1 for the +1 and -1 standard deviations (σ) of Tmax variation for entire the SWUS. The …

Laboratory Measurements Of Contact Nucleation By Mineral Dusts, Bacteria, And Soluble Salts, Joseph Niehaus

Dissertations, Master's Theses and Master's Reports

We present results from experiments that emulate atmospheric ice nucleation by aerosols. We have refined experimental techniques to improve measurements of ice forming nuclei in the contact mode. Our results show that atmospherically relevant dusts such as kaolinite, feldspar, rhyolitic ash, and Arizona Test Dust have efficiencies in the contact mode that are higher than the immersion mode. Experiments with bacteria show that biological material has the potential to contribute significantly to ice concentrations, but has large variability. By choosing a soluble compound as an ice nucleus, we are able to place bounds on the timescale for contact freezing and …

Testing Lidar-Radar Derived Drop Sizes Against In Situ Measurements, Mary Amanda Shaw

Dissertations, Master's Theses and Master's Reports

How well can a co-located lidar and radar retrieve a drop size distribution in drizzling clouds? To answer, we mimic scattering from a laboratory cloud to retrieve a lidar-radar effective diameter. Using only the shape parameter of the gamma-distributed drops, the mean diameter of the drops can be estimated from lidar-radar effective diameter to within a few percent of the true mean. In practice, the shape parameter of the gamma distribution is not known. To set bounds, mean diameters were calculated from the lidar-radar effective diameter using a range of in situ measured gamma shape parameters. The estimated means varied …

Data From: How Uncertainty In The Neutral Wind Limits The Accuracy Of Ionospheric Modeling And Forecasting, Michael David, Jan Sojka, Robert W. Schunk

Browse all Datasets

Output files from runs of the TDIM ionospheric model used for the figures and calculations in the article in JGR Space Physics.

Improved Prediction Of Severe Thunderstorms Over The Indian Monsoon Region Using High-Resolution Soil Moisture And Temperature Initialization, K. K. Osuri, R. Nadimpalli, U. C. Mohanty, F. Chen, M. Rajeevan, Dev Niyogi

Department of Earth, Atmospheric, and Planetary Sciences Faculty Publications

The hypothesis that realistic land conditions such as soil moisture/soil temperature (SM/ST) can significantly improve the modeling of mesoscale deep convection is tested over the Indian monsoon region (IMR). A high resolution (3 km foot print) SM/ST dataset prepared from a land data assimilation system, as part of a national monsoon mission project, showed close agreement with observations. Experiments are conducted with (LDAS) and without (CNTL) initialization of SM/ST dataset. Results highlight the significance of realistic land surface conditions on numerical prediction of initiation, movement and timing of severe thunderstorms as compared to that currently being initialized by climatological fields …

Earthkam In The Classroom: Enhanced Stem Learning Through Earth Observations, Angela Burke

Summer Community of Scholars Posters (RCEU and HCR Combined Programs)

No abstract provided.

Characteristics Of Tornado Debris Signatures In The 30 June-1 July 2014 Quasi-Linear Convective System Tornado Outbreak, Adam Clayton

Summer Community of Scholars Posters (RCEU and HCR Combined Programs)

No abstract provided.

A Polarimetric Radar Analysis Of The March 31, 2016 Supercell, Kaitlyn Pate, Sarah M. Stough

Summer Community of Scholars Posters (RCEU and HCR Combined Programs)

No abstract provided.

Assessing The Utility Of Imaging Radar For Identifying White Sand Vegetation Structure, Jessica Rosenqvist

Dissertations and Theses

White sand vegetation communities are wide spread across South America; found in Peru, Venezuela, Brazilian Amazon and Guyana. They are distributed in patches ranging from <1 km2 to greater than tens of square kilometers and their origins and locations are still not well understood. The communities are related to a variety of factors (soil type, flooding, nutrient content and fire); hence a precise definition for the ecosystem is still not fully defined. Nevertheless, the result of these variations creates a unique environment for endemic plant and animal species to thrive. Furthermore, analysis of these areas has been very scattered and identification of local white sand areas (<1 km2) have not been accomplished. In addition, identification of these locations has currently only used optical satellite imagery (Landsat, MODIS). Hence, in this project, we have attempted to use synthetic aperture radar to create a classification system to locate the white sand vegetation systems. The goal is to be able to apply this method to identify white sand vegetation distribution across South America. The region of focus for this thesis has been in Aracá, a large white sand area located in Brazil in the State of Amazonas. Due to the lack of ground reference data, a classified map by Capurucho et al. (2013), generated using Landsat data, was used as a comparison and reference. JAXA’s ALOS-1 PALSAR (L-band), ESA’s Sentinel-1A (C-band) and NASA’s SRTM sensors were used for land classification. As microwave signals penetrate clouds and haze, the advantage of using sensors with this wavelength allows for an unobstructed coverage of the landscape all year round. Different combinations of polarizations and wavelengths were used during the analysis to try and separate the white sand vegetation from water and terra firme forest. The resulting classification images showed a 30% agreement with the classification map by Capurucho et al. It is important to note, that this number is in fact an agreement percentage as the map used was a classification image and coarse in resolution (due to the lack of reference data). Therefore, this value does not imply a bad classification. Future work will include time-series data, precise ground reference points and data from other sensors such as ALOS-2 PALSAR, to improve the classification accuracy.

Evidence For The Drainage Of A Superglacial Lake As The Source Of Seismic Waves Recorded At A Regional Distance, Erik J. Orantes

Dissertations and Theses

Surface melting during the summer leads to the formation of lakes on the Greenland Ice Sheet surface, known as supraglacial lakes. Some of these lakes drain through cracks in their beds and release the water into the ice sheet. Previous studies suggest that some of the water reaches the bedrock, enabling basal sliding, which could potentially increase glacial discharge (Sundal et al., 2009). Das et al. (2008) showed that supraglacial lake drainage can be accompanied by seismic activity, but little work has been done on the regional detection of such waves. The present study analyzes seismic data for the period …

Chemical Transport Of Neutral Atmospheric Constituents By Waves And Turbulence: Theory And Observations, Chester S. Gardner, Alan Liu

Publications

Vertical chemical transport occurs when the density fluctuations of a species, caused by perturbations of its chemistry, are strongly correlated with the vertical wind fluctuations. Chemical transport can exceed dynamical and eddy transport of chemically active species. Theoretical expressions are derived for the chemical fluxes and transport velocities and used to characterize the vertical transport of mesospheric O3 and meteoric Na and Fe between 85 and 100 km. Chemical transport is dependent on the intrinsic frequency spectrum of the temperature fluctuations and on the chemical cutoff periods of the species. For O3 only high-frequency fluctuations contribute to chemical transport because …