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• 1. [Article] Evaluation of Large‑Scale Meteorological Patterns Associated with Temperature Extremes in the NARCCAP Regional Climate Model Simulations

  Large-scale meteorological patterns (LSMPs) associated with temperature extremes are evaluated in a suite of regional climate model (RCM) simulations contributing to the North American Regional Climate ...

  Citation × Citation Citation Abstract Copy Title: Evaluation of Large‑Scale Meteorological Patterns Associated with Temperature Extremes in the NARCCAP Regional Climate Model Simulations Author: Loikith, Paul C., Waliser, Duane E., Lee, Huikyo, Neelin, J. David, Lintner, Benjamin, McGinnis, Seth, Mears, Linda, Kim, Jinwon Year: 2015 Large-scale meteorological patterns (LSMPs) associated with temperature extremes are evaluated in a suite of regional climate model (RCM) simulations contributing to the North American Regional Climate Change Assessment Program. LSMPs are characterized through composites of surface air temperature, sea level pressure, and 500 hPa geopotential height anomalies concurrent with extreme temperature days. Six of the seventeen RCM simulations are driven by boundary conditions from reanalysis while the other eleven are driven by one of four global climate models (GCMs). Four illustrative case studies are analyzed in detail. Model fidelity in LSMP spatial representation is high for cold winter extremes near Chicago. Winter warm extremes are captured by most RCMs in northern California, with some notable exceptions. Model fidelity is lower for cool summer days near Houston and extreme summer heat events in the Ohio Valley. Physical interpretation of these patterns and identification of wellsimulated cases, such as for Chicago, boosts confidence in the ability of these models to simulate days in the tails of the temperature distribution. Results appear consistent with the expectation that the ability of an RCM to reproduce a realistically shaped frequency distribution for temperature, especially at the tails, is related to its fidelity in simulating LMSPs. Each ensemble member is ranked for its ability to reproduce LSMPs associated with observed warm and cold extremes, identifying systematically high performing RCMs and the GCMs that provide superior boundary forcing. The methodology developed here provides a framework for identifying regions where further process-based evaluation would improve the understanding of simulation error and help guide future model improvement and downscaling efforts. Title: Evaluation of Large‑Scale Meteorological Patterns Associated with Temperature Extremes in the NARCCAP Regional Climate Model Simulations Author: Loikith, Paul C., Waliser, Duane E., Lee, Huikyo, Neelin, J. David, Lintner, Benjamin, McGinnis, Seth, Mears, Linda, Kim, Jinwon Year: 2015 Large-scale meteorological patterns (LSMPs) associated with temperature extremes are evaluated in a suite of regional climate model (RCM) simulations contributing to the North American Regional Climate Change Assessment Program. LSMPs are characterized through composites of surface air temperature, sea level pressure, and 500 hPa geopotential height anomalies concurrent with extreme temperature days. Six of the seventeen RCM simulations are driven by boundary conditions from reanalysis while the other eleven are driven by one of four global climate models (GCMs). Four illustrative case studies are analyzed in detail. Model fidelity in LSMP spatial representation is high for cold winter extremes near Chicago. Winter warm extremes are captured by most RCMs in northern California, with some notable exceptions. Model fidelity is lower for cool summer days near Houston and extreme summer heat events in the Ohio Valley. Physical interpretation of these patterns and identification of wellsimulated cases, such as for Chicago, boosts confidence in the ability of these models to simulate days in the tails of the temperature distribution. Results appear consistent with the expectation that the ability of an RCM to reproduce a realistically shaped frequency distribution for temperature, especially at the tails, is related to its fidelity in simulating LMSPs. Each ensemble member is ranked for its ability to reproduce LSMPs associated with observed warm and cold extremes, identifying systematically high performing RCMs and the GCMs that provide superior boundary forcing. The methodology developed here provides a framework for identifying regions where further process-based evaluation would improve the understanding of simulation error and help guide future model improvement and downscaling efforts. Close

• 2. [Article] NWA 8614: The Least Heated Winonaite

  Northwest Africa 8614 is classified as a winonaite on the basis of oxygen isotope ratios, mineralogy, and highly reduced chemistry. Unlike other winonaites, it contains numerous and readily apparent chondrules. ...

  Citation × Citation Citation Abstract Copy Title: NWA 8614: The Least Heated Winonaite Author: Farley, Karla, Ruzicka, Alexander M., Armstrong, Katherine Year: 2015 Northwest Africa 8614 is classified as a winonaite on the basis of oxygen isotope ratios, mineralogy, and highly reduced chemistry. Unlike other winonaites, it contains numerous and readily apparent chondrules. Here we discuss various features of NWA 8614 and the possible significance of the meteorite. Petrological and chemical analyses were performed using optical microscopy with a DM2500 Leica petrographic microscope and a Zeiss Sigma VP-FEG scanning electron microscope (SEM) with a high-efficiency energy dispersive spectrometer (EDS). Oxygen isotopes were analyzed by Karen Ziegler at the University of New Mexico on acid-washed samples to remove terrestrial weathering products. Owing to the abundance of chondrules, NWA 8641 may be one of the least heated winonaites, and therefore may provide clues to the chondritic protolith of the winonaite parent body. Overall textures are similar to those found in type 6 chondrites that escaped significant melting. Despite similar geothermometer temperatures for various mineral pairs, NWA 8614 apparently did not attain Fe-Mg equilibrium between olivine and pyroxene. Like other winonaites, NWA 8614 has olivine compositions that are too magnesian for equilibrium relative to low-Ca pyroxene. Among winonaites as a whole, there is no evidence for a curved trend between Fa and Fs compositions as would be expected for FeO-reduction during metamorphism [Benedix, et al 1998], nor for mineral compositions that correlate with geothermometry temperatures. This argues against a single metamorphic FeO-reduction trend from a common chondritic precursor. Instead, protoliths for different winonaites may have varied slightly in composition. Title: NWA 8614: The Least Heated Winonaite Author: Farley, Karla, Ruzicka, Alexander M., Armstrong, Katherine Year: 2015 Northwest Africa 8614 is classified as a winonaite on the basis of oxygen isotope ratios, mineralogy, and highly reduced chemistry. Unlike other winonaites, it contains numerous and readily apparent chondrules. Here we discuss various features of NWA 8614 and the possible significance of the meteorite. Petrological and chemical analyses were performed using optical microscopy with a DM2500 Leica petrographic microscope and a Zeiss Sigma VP-FEG scanning electron microscope (SEM) with a high-efficiency energy dispersive spectrometer (EDS). Oxygen isotopes were analyzed by Karen Ziegler at the University of New Mexico on acid-washed samples to remove terrestrial weathering products. Owing to the abundance of chondrules, NWA 8641 may be one of the least heated winonaites, and therefore may provide clues to the chondritic protolith of the winonaite parent body. Overall textures are similar to those found in type 6 chondrites that escaped significant melting. Despite similar geothermometer temperatures for various mineral pairs, NWA 8614 apparently did not attain Fe-Mg equilibrium between olivine and pyroxene. Like other winonaites, NWA 8614 has olivine compositions that are too magnesian for equilibrium relative to low-Ca pyroxene. Among winonaites as a whole, there is no evidence for a curved trend between Fa and Fs compositions as would be expected for FeO-reduction during metamorphism [Benedix, et al 1998], nor for mineral compositions that correlate with geothermometry temperatures. This argues against a single metamorphic FeO-reduction trend from a common chondritic precursor. Instead, protoliths for different winonaites may have varied slightly in composition. Close

• 3. [Article] Air-sea interaction over ocean fronts and eddies

  To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by Elsevier ...

  Citation × Citation Citation Abstract Copy Title: Air-sea interaction over ocean fronts and eddies Author: Small, R. J., O'Neill, L., Cornillon, P., Spall, M., Seo, H., de Szoeke, Simon P., Xie, S. P., Song, Q., Minobe, S. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by Elsevier and can be found at: http://www.journals.elsevier.com/dynamics-of-atmospheres-and-oceans. Title: Air-sea interaction over ocean fronts and eddies Author: Small, R. J., O'Neill, L., Cornillon, P., Spall, M., Seo, H., de Szoeke, Simon P., Xie, S. P., Song, Q., Minobe, S. To the best of our knowledge, one or more authors of this paper were federal employees when contributing to this work. This is the publisher’s final pdf. The published article is copyrighted by Elsevier and can be found at: http://www.journals.elsevier.com/dynamics-of-atmospheres-and-oceans. Close

• 4. [Article] Development of a synoptic map-pattern climatology to supplement current weather forecasting methods

  Many meteorologists rely heavily on their experience of past weather events to supplement their forecasting tools, such as using past experience to help decide between conflicting numerical weather prediction ...

  Citation × Citation Citation Abstract Copy Title: Development of a synoptic map-pattern climatology to supplement current weather forecasting methods Author: Frey, Melissa D. (Melissa Dawn) Many meteorologists rely heavily on their experience of past weather events to supplement their forecasting tools, such as using past experience to help decide between conflicting numerical weather prediction models. Experiential knowledge is an important piece of forecasting, however it is highly subjective and variable from one forecaster to another. In efforts to replace this experiential knowledge with a more objective record, this thesis explains how a synoptic map-pattern climatology was created and how it could be used as a contribution to weather forecasting methods. Creating the map-pattern climatology was a two step process: first atmospheric flow patterns at the 500-millibar level for the selected region were categorized by type; and second surface level weather data were correlated with the map-types found. The atmospheric flow patterns over the Pacific Northwest region were found using a correlation-based method. Each day during the winter months of December, January, and February for the past 58 years was categorized by map-type. This resulted in 5,235 days that were classified into 20 distinct map-type groups. Once the map-types were found, temperature, precipitation, and snowfall data from stations throughout Oregon and Washington were then correlated to the map-type data. The weather data were calculated for three spatial scales: an average of Oregon and Washington combined; average by Oregon climate zone; and for a single city. It was found that each map-type is associated with a unique weather environment at the surface. As an additional study, the distribution of map-types during El Niño and La Niña years was studied in combination with the surface weather data. It was found that El Niño and La Niña years have quite different map-type distributions compared to normal years, and the weather resulting at the surface was also far from average. Once completed, this Pacific Northwest climatology provided a record of the most common flow patterns and resulting weather at the surface. If distributed in a format in which current atmospheric flow data could be compared to historical map-type data, this synoptic map-pattern climatology could be used as a forecasting tool. In order for this information to replace the previously relied upon experiential knowledge, it would be necessary to know the forecast day’s projected map-type along with the historical surface weather data associated with that map-type. If distributed in this way, weather forecasters would have easy access to what has happened historically with any given map-type, thus replacing their variable and subjective experiential knowledge with an objective and accurate record. Title: Development of a synoptic map-pattern climatology to supplement current weather forecasting methods Author: Frey, Melissa D. (Melissa Dawn) Many meteorologists rely heavily on their experience of past weather events to supplement their forecasting tools, such as using past experience to help decide between conflicting numerical weather prediction models. Experiential knowledge is an important piece of forecasting, however it is highly subjective and variable from one forecaster to another. In efforts to replace this experiential knowledge with a more objective record, this thesis explains how a synoptic map-pattern climatology was created and how it could be used as a contribution to weather forecasting methods. Creating the map-pattern climatology was a two step process: first atmospheric flow patterns at the 500-millibar level for the selected region were categorized by type; and second surface level weather data were correlated with the map-types found. The atmospheric flow patterns over the Pacific Northwest region were found using a correlation-based method. Each day during the winter months of December, January, and February for the past 58 years was categorized by map-type. This resulted in 5,235 days that were classified into 20 distinct map-type groups. Once the map-types were found, temperature, precipitation, and snowfall data from stations throughout Oregon and Washington were then correlated to the map-type data. The weather data were calculated for three spatial scales: an average of Oregon and Washington combined; average by Oregon climate zone; and for a single city. It was found that each map-type is associated with a unique weather environment at the surface. As an additional study, the distribution of map-types during El Niño and La Niña years was studied in combination with the surface weather data. It was found that El Niño and La Niña years have quite different map-type distributions compared to normal years, and the weather resulting at the surface was also far from average. Once completed, this Pacific Northwest climatology provided a record of the most common flow patterns and resulting weather at the surface. If distributed in a format in which current atmospheric flow data could be compared to historical map-type data, this synoptic map-pattern climatology could be used as a forecasting tool. In order for this information to replace the previously relied upon experiential knowledge, it would be necessary to know the forecast day’s projected map-type along with the historical surface weather data associated with that map-type. If distributed in this way, weather forecasters would have easy access to what has happened historically with any given map-type, thus replacing their variable and subjective experiential knowledge with an objective and accurate record. Close

• 5. [Article] Atmospheric Mesoscale Modeling of Water and Clouds During Northern Summer on Mars

  This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by the Authors and published by Elsevier. It can be found at: http://www.journal...

  Citation × Citation Citation Abstract Copy Title: Atmospheric Mesoscale Modeling of Water and Clouds During Northern Summer on Mars Author: Tyler, Daniel, Jr., Barnes, Jeffrey R. This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by the Authors and published by Elsevier. It can be found at: http://www.journals.elsevier.com/icarus/. Title: Atmospheric Mesoscale Modeling of Water and Clouds During Northern Summer on Mars Author: Tyler, Daniel, Jr., Barnes, Jeffrey R. This is an author's peer-reviewed final manuscript, as accepted by the publisher. The published article is copyrighted by the Authors and published by Elsevier. It can be found at: http://www.journals.elsevier.com/icarus/. Close