Oceanography and Atmospheric Sciences and Meteorology Commons^™

Cloud-Scale Ice-Supersaturated Regions Spatially Correlate With High Water Vapor Heterogeneities, Minghui Diao, Mark Zondlo, Andrew Heymsfield, L. Avallone, M. Paige, Stuart Beaton, T. Campos, D. Rogers

Faculty Publications, Meteorology and Climate Science

Cirrus clouds have large yet uncertain impacts on Earth's climate. Ice supersaturation (ISS) – where the relative humidity with respect to ice (RHi) is greater than 100% – is the prerequisite condition of ice nucleation. Here we use 1 Hz (~230 m) in situ, aircraft-based observations from 87° N to 67° S to analyze the spatial characteristics of ice-supersaturated regions (ISSRs). The median length of 1-D horizontal ISSR segments is found to be very small (~1 km), which is 2 orders of magnitude smaller than previously reported. To understand the conditions of these small-scale ISSRs, we compare individual ISSRs with …

Quantifying The Impact Of Atmospheric Deposition On The Biogeochemistry Of Fe And Al In The Upper Ocean: A Decade Of Collaboration With The Us Clivar-Co2 Repeat Hydrography Program, Maxime Grand, Clifton Buck, William Landing, Christopher Measures, Mariko Hatta, William Hiscock, Matthew Brown, Joseph Resing

Faculty Publications

The aerosol deposition of continental material and its partial dissolution in the surface ocean exerts an important control on the distribution of iron and other potentially limiting trace metal (TM) micronutrients in the open ocean. This dust deposition has implications for the regulation of global climate through the coupling of biolimiting TM cycles, marine productivity, and the global carbon cycle. Thus, it is important to determine the locations of dust deposition in the open ocean and to quantify the magnitude and subsequent dissolution of the dust. At present, there are too few dust deposition estimates and solubility measurements in the …

Representation Of Ethiopian Wet Spells In Global And Nested Models, Mark Jury, Sen Chiao

Faculty Publications, Meteorology and Climate Science

Weather forecast and reanalysis models exhibit different performance in daily rainfall estimation over the Ethiopian highlands, 2000–2012, with ECMWF closer to observations than other models. Background is given to illustrate the Hadley circulation and easterly jets over Ethiopia, using sections on 37°E in July–August 2011. ECMWF reanalysis has a narrow band of rainfall >15 mm/day on 10°N, consistent with TRMM satellite estimates, associated with a steep gradient in meridional wind. MERRA and GFS models have a wider band of rainfall and weaker gradients in meridional winds. The contrasting background states influence a nested WRF model simulation of heavy rain in …

Prescribed Burning Of Logging Slash In The Boreal Forest Of Finland: Emissions And Effects On Meteorological Quantities And Soil Properties, A. Virkkula, J. Levula, T. Pohja, P. Aalto, P. Keronen, S. Schobesberger, Craig Clements, L. Pirjola, A. Kieloaho, L. Kulmala, H. Aaltonen, J. Patoskoski, J. Pumpanen, J. Rinne, T. Ruuskanen, M. Pihlatie, H. Mannien, V. Aaltonen, H. Junninen, T. Petaja, J. Backman, M. Dal Maso, T. Nieminen, T. Olsson, T. Grönholm, J. Aalto, T. Virtanen, M. Kajos, V. Kerminen, D. Shultz, J. Kukkonen, M. Sofiev, G. De Leeuw, J. Back, P. Hari, M. Kulmala

Faculty Publications, Meteorology and Climate Science

A prescribed fire experiment was conducted on 26 June 2009 in Hyytiälä, Finland, to study aerosol and trace gas emissions from prescribed fires of slash fuels and the effects of fire on soil properties in a controlled environment. A 0.8 ha forest near the SMEAR II measurement station (Station for Measuring Ecosystem-Atmosphere Relations) was cut clear; some tree trunks, all tree tops and branches were left on the ground and burned. The amount of burned organic material was ~46.8 tons (i.e., ~60 tons ha−1). The flaming phase lasted 2 h 15 min, the smoldering phase 3 h. Measurements were conducted …

Airborne Measurements Of Aerosols And Carbon Dioxide During A Prescribed Fire Experiment At A Boreal Forest Site, Aki Virkkula, Toivo Pohja, Pasi Aalto, Petri Keronen, Siegfried Schobesberger, Craig Clements, Tuukka Petäjä, Juha Nikmo, Markku Kulmala

Faculty Publications, Meteorology and Climate Science

During a prescribed fire experiment, CO2 and particle number concentrations, light scattering and absorption coefficients were measured from a Cessna 172 airplane. Peak number concentrations were (3 ± 1) x 106 cm–3 and they decreased faster than what can be explained by coagulation alone. The single-scattering albedo of particles grew from the values of 0.4 ± 0.1 closest to the emissions to the values of 0.8 ± 0.1 at the distance of 400 m from the emissions. The mean Ângström exponent of absorption, 1.70 ± 0.24, is in line with the published spectral absorption values of wood-smoke aerosol. The estimated …

Ice Crystal Formation And Evolution In Five Campaigns: Start08, Hippo Global, Dc3, Predict And Torero, Minghui Diao, Joshua Digangi, Anthony O’Brien, Mark Zondlo

Faculty Publications, Meteorology and Climate Science

In order to understand the microphysical properties of cirrus clouds, it is important to understand the formation and evolution of the environments where ice crystals form and reside on the microscale (~100 m). Uncertainties remain in simulating/parameterizing the evolution of ice crystals, which require more analyses in the Lagrangian view. However, most in situ observations are in the Eulerian view and are restricted from examining the lifecycle of cirrus clouds. In this work, a new method of Diao et al. GRL (2013)* is used to separate out five phases of ice crystal evolution, using the horizontal spatial relationships between ice …

Case Studies Of Tropical Cyclones And Phytoplankton Blooms Over Atlantic And Pacific Regions, Ashley Merritt-Takeuchi, Sen Chiao

Faculty Publications, Meteorology and Climate Science

This study investigates phytoplankton blooms following the passage of tropical cyclones in the Atlantic and Pacific Ocean basins. The variables of sea surface temperature (SST), chlorophyll (Chl-a), precipitation, and storm surface winds were monitored for two case studies, Typhoon Xangsane (2006) and Hurricane Earl (2010). Strong near-surface wind from tropical cyclones creates internal friction, which causes deep nutrient enriched waters to displace from the bottom of the ocean floor up toward the surface. In return, the abundance of upwelled nutrients near the surface provides an ideal environment for the growth of biological substances such as chlorophyll and phytoplankton. The inverse …

Evolution Of Ice Crystal Regions On The Microscale Based On In Situ Observations, Minghui Diao, Mark Zondlo, Andrew Heymsfield, Stuart Beaton, David Rogers

Faculty Publications, Meteorology and Climate Science

[1] Microphysical properties of cirrus clouds largely influence their atmospheric radiative forcing. However, uncertainties remain in simulating/parameterizing the evolution of ice crystals. These uncertainties require more analyses in the Lagrangian view, yet most in situ observations are in the Eulerian view. Here we demonstrate a new method to separate out five phases of ice crystal evolution, using the horizontal spatial relationships between ice supersaturated regions (ISSRs) and ice crystal regions (ICRs). Based on global in situ data sets, we show that the samples of clear-sky ISSRs, ice crystal formation/growth, and evaporation/sedimentation are ~20%, 10%, and 70% of the total ISSR …

Validation Of Airs/Amsu - A Water Vapor And Temperature Data With In Situ Aircraft Observations From The Surface To Ut/Ls From 87°N–67°S, Minghui Diao, Loayeh Jumbam, Justin Sheffield, Eric Wood, Mark Zondlo

Faculty Publications, Meteorology and Climate Science

[1] Validation of the Atmospheric Infrared Sounder (AIRS)/Advanced Microwave Sounding Unit (AMSU-A) data set with in situ observations provides useful information on its application to climate and weather studies. However, different space/time averaging windows have been used in past studies, and questions remain on the variation of errors in space, such as between land/ocean and the Northern/Southern Hemispheres. In this study, in situ aircraft measurements of water vapor and temperature are compared with the AIRS/AMSU-A retrievals (Version 5 Level 2) from 87°N to 67°S and from the surface to the upper troposphere and lower stratosphere (UT/LS). By using a smaller …

Leeside Boundary Layer Confluence And Afternoon Thunderstorms Over Mayaguez, Puerto Rico, Mark Jury, Sen Chiao

Faculty Publications, Meteorology and Climate Science

The midsummer boundary layer (BL) circulation and afternoon thunderstorm convection on the lee side of Puerto Rico is studied using observations and high-resolution models. Satellite infrared data help to identify cases on 5 and 14 June 2010 when midday surface temperatures show a 2°C gradient between land and sea and afternoon cloud-top temperatures <−60°C. Acoustic sounder profiles are analyzed for climatology, wind shear, turbulence, and diurnal cycles in the 40-300-m layer. Weather Research and Forecasting (WRF) model simulations indicate that sea-breeze flow is entrained into convective cells near Mayaguez, Puerto Rico. The simulated BL wind shear is too weak (0.5 × 10−2 s−1) in comparison with the acoustic sounder (2 × 10−2 s−1). Model 900-hPa winds are southeasterly and spread simulated convection too far north in comparison with radar. The pattern of near-surface winds in the island wake triggers afternoon thunderstorms near Mayaguez. A feature of the confluent circulation around Puerto Rico is opposing shear zones on the leeward corners of the island and a sea breeze of 5 m s−1 over the west coast during midday. [ABSTRACT FROM AUTHOR] . Copyright of Journal of Applied Meteorology & Climatology is the property of American Meteorological Society and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.).

Numerical Investigations Of Convective Initiation In Barbados, Kim Whitehall, Sen Chiao, Margarette Mayers-Als

Faculty Publications, Meteorology and Climate Science

Localized convection in Barbados accounts for hazardous conditions and a significant percentage of the island’s annual rainfall. The feature results in rainfall accumulations exceeding 50 mm in 3 hours or less, over isolated locations. Weather Research and Forecasting model (WRF) simulations are conducted for a rapid convective initiated and heavy precipitation event of 26 August 2008 over Barbados. The simulation results from the 1 km grid resolution domain depict that the shallow topography on the island plays a significant role in enhancing convective activity under weak synoptically disturbed conditions. The model results also demonstrate that the driving forces for the …

Evaluation Of Wrf-Sfire Performance With Field Observations From The Fireflux Experiment, A. Kochanski, M. Jenkins, J. Mandel, J. Beezley, Craig Clements, S. Krueger

Faculty Publications, Meteorology and Climate Science

This study uses in situ measurements collected during the FireFlux field experiment to evaluate and improve the performance of the coupled atmosphere–fire model WRF-SFIRE. The simulation by WRF-SFIRE of the experimental burn shows that WRF-SFIRE is capable of providing realistic head-fire rate of spread and vertical temperature structure of the fire plume, and fire-induced surface flow and vertical velocities within the plume up to 10 m above ground level. The simulation captured the changes in wind speed and direction before, during, and after fire front passage, along with the arrival times of wind speed, temperature, and updraft maxima, at the …

Kinematic Structure Of A Wildland Fire Plume Observed By Doppler Lidar, A. Charland, Craig Clements

Faculty Publications, Meteorology and Climate Science

Wildland fires present a challenging environment to make meteorological measurements. Observations in the vicinity of wildland fires are needed to better understand fire-atmosphere interactions and to provide data for the evaluation of coupled fire-atmosphere models. An observational study was conducted during a low-intensity prescribed fire in an area of complex terrain with grass fuels east of San José, California. A ground-based scanning Doppler lidar acquired radial wind velocities and backscatter intensity in and around the fire plume from multiple horizontal and vertical scans. The development of a convergence zone was consistently observed to exist downwind of the plume and was …

Trends In The Ams Education Symposium And Highlights From 2012, Rajul Pandya, Donna Charlevoix, Eugene Cordero, David Smith, Sepi Yalda

Faculty Publications, Meteorology and Climate Science

The Department of Meteorology (now Atmospheric Sciences) at the University of Utah faced reductions in state funding in 2008 that reduced support for nontenured instructors at the same time that the faculty were becoming increasingly successful obtaining federally supported research grants. A faculty retreat and subsequent discussions led to substantive curriculum changes to modernize the curriculum, enhance course offerings for undergraduate and graduate students, and improve the overall efficiency of the academic program. Maintaining discipline standards and existing teaching loads were important constraints on these changes. Key features of the curriculum revisions for undergraduate majors included eliminating a very rigid …

University Scholar Series: Craig B. Clements, Craig B. Clements

University Scholar Series

Groundbreaking Research on Wildfire Weather

On November 28, 2012 Craig B. Clements spoke in the University Scholar Series hosted by Provost Ellen Junn at the Dr. Martin Luther King, Jr. Library. Craig Clements is an associate professor in the Department of Meteorology and Climate Science who received a $900,000 National Science Foundation CAREER grant for his work in tracking atmospheric conditions in and around wildfires. His work will better help predict wildfire behavior and conditions that could lead to increased wildfire danger.

Water Vapor And Temperature Comparisons Between Airs/Amsu-A And In Situ Aircraft Observations From 87°N To 67°S And Sensitivities To Spatial And Temporal Differences, Minghui Diao, Loayeh Jumbam, Justin Sheffield, Eric Wood, Mark Zondlo

Faculty Publications, Meteorology and Climate Science

No abstract available.

Bioactive Trace Metal Distributions And Biogeochemical Controls In The Southern Ocean, Christopher Measures, Mariko Hatta, Maxime Grand

Faculty Publications

Extensive sampling in many regions of the Southern Ocean has demonstrated that surface water concentrations of dissolved Fe are low enough to limit phytoplankton growth. In contrast, there is currently no evidence that other bioactive elements (e.g., Mn, Zn, Co) are similarly limiting. Although atmospheric input of dissolved Fe to Southern Ocean surface waters appears to be low, resuspension of sediments from shallow regions around islands and the Antarctic coastline can inject significant amounts of Fe into the surrounding waters, stimulating primary production and providing a natural laboratory for studying the response of biological systems to natural Fe fertilization processes. …

Reproduction Of Twentieth Century Intradecadal To Multidecadal Surface Temperature Variability In Radiatively Forced Coupled Climate Models, Patrick T. Brown, Eugene C. Cordero, Steven A. Mauget

Faculty Publications, Meteorology and Climate Science

[1] Coupled Model Intercomparison Project 3 simulations that included time-varying radiative forcings were ranked according to their ability to consistently reproduce twentieth century intradecadal to multidecadal (IMD) surface temperature variability at the 5° by 5° spatial scale. IMD variability was identified using the running Mann-Whitney Z method. Model rankings were given context by comparing the IMD variability in preindustrial control runs to observations and by contrasting the IMD variability among the ensemble members within each model. These experiments confirmed that the inclusion of time-varying external forcings brought simulations into closer agreement with observations. Additionally, they illustrated that the magnitude of …

Will Extreme Climatic Events Facilitate Biological Invasions?, Jeffrey M. Diez, Carla M. D'Antonio, Jeffrey S. Dukes, Edwin D. Grosholz, Julian D. Olden, Cascade J.B. Sorte, Dana M. Blumenthal, Bethany A. Bradley, Regan I. Early, Inés Ibáñez, Sierra J. Jones, Joshua J. Lawler, Luke P. Miller

Faculty Publications, Biological Sciences

Extreme climatic events (ECEs) – such as unusual heat waves, hurricanes, floods, and droughts – can dramatically affect ecological and evolutionary processes, and these events are projected to become more frequent and more intense with ongoing climate change. However, the implications of ECEs for biological invasions remain poorly understood. Using concepts and empirical evidence from invasion ecology, we identify mechanisms by which ECEs may influence the invasion process, from initial introduction through establishment and spread. We summarize how ECEs can enhance invasions by promoting the transport of propagules into new regions, by decreasing the resistance of native communities to establishment, …

Ice Supersaturation And Cirrus Clouds In Hippo Global Campaign #1-5, Minghui Diao, Mark Zondlo

Faculty Publications, Meteorology and Climate Science

No abstract available.

Evaluating Modeled Intra- To Multidecadal Climate Variability Using Running Mann–Whitney Z Statistics, Steven A. Mauget, Eugene C. Cordero, Patrick T. Brown

Faculty Publications, Meteorology and Climate Science

An analysis method previously used to detect observed intra- to multidecadal (IMD) climate regimes was adapted to compare observed and modeled IMD climate variations. Pending the availability of the more appropriate phase 5 Coupled Model Intercomparison Project (CMIP-5) simulations, the method is demonstrated using CMIP-3 model simulations. Although the CMIP-3 experimental design will almost certainly prevent these model runs from reproducing features of historical IMD climate variability, these simulations allow for the demonstration of the method and illustrate how the models and observations disagree. This method samples a time series’s data rankings over moving time windows, converts those ranking sets …

Application Of A Mini-Unmanned Aircraft System For In Situ Monitoring Of Fire Plume Thermodynamics Properties, Caroline Keifer, Craig Clements, Brian Potter

Faculty Publications, Meteorology and Climate Science

Direct measurements of wildland fire plume properties are rare because of difficult access to regions near the fire front and plume. Moisture released from combustion, in addition to added heat, can enhance buoyancy and convection, influencing fire behavior. In this study, a mini unmanned aircraft system (miniUAS) was used to obtain in situ measurements of temperature and relative humidity during a prescribed fire. The miniUAS was successfully maneuvered through the plume and its associated turbulence and provided observations of temperature and humidity profiles from near the centerline of the plume. Within the plume, the water vapor mixing ratio increased by …

Global Change, Global Trade, And The Next Wave Of Plant Invasions, Bethany A. Bradley, Dana M. Blumenthal, Regan Early, Edwin D. Grosholz, Joshua J. Lawler, Luke P. Miller, Cascade J.B. Sorte, Carla M. D'Antonio, Jeffrey M. Diez, Jeffrey S. Dukes, Ines Ibanez, Julian D. Olden

Faculty Publications, Biological Sciences

Many non-native plants in the US have become problematic invaders of native and managed ecosystems, but a new generation of invasive species may be at our doorstep. Here, we review trends in the horticultural trade and invasion patterns of previously introduced species and show that novel species introductions from emerging horticultural trade partners are likely to rapidly increase invasion risk. At the same time, climate change and water restrictions are increasing demand for new types of species adapted to warm and dry environments. This confluence of forces could expose the US to a range of new invasive species, including many …

Meso-Circulation Associated With Summer Convection Over The Central Antilles, Mark Jury, Sen Chiao

Faculty Publications, Meteorology and Climate Science

The mesoscale structure of the circulation and convection over central Caribbean Antilles islands in midsummer is analyzed. Afternoon thunderstorms are frequent over islands such as Hispaniola and Jamaica as confluent trade winds circulate over heated mountainous topography. Observational data from a rain gauge network, profiles from aircraft and radiosonde, satellite estimates of rainfall, and mesoscale reanalysis fields are studied with a focus on July 2007. A statistical decomposition of 3-hourly high-resolution satellite rainfall reveals an “island mode” with afternoon convection. Trade winds pass over the mountains of Hispaniola and Jamaica with a Froude number <1, leading to a long meandering wake. The Weather Research and Forecasting model is used to simulate climatic conditions during July 2007. The model correctly locates areas of diurnal rainfall that develop because of island heat fluxes, confluent sea breezes, and mountain wakes.

Rumbling In The Benthos: Acoustic Ecology Of The California Mantis Shrimp Hemisquilla Californiensis, E. Staaterman, C. Clark, A. Gallagher, M. Devries, T. Claverie, S. Patek

Faculty Publications, Biological Sciences

Although much research has focused on acoustic mapping and exploration of the benthic environment, little is known about the acoustic ecology of benthic organisms, particularly benthic crustaceans. Through the use of a coupled audio–video system, a hydrophone array, and an autonomous recording unit, we tested several hypotheses about the field acoustics of a benthic marine crustacean, Hemisquilla califor­niensis. Living in muddy burrows in southern California, these large mantis shrimp produce low frequency ‘rumbles’ through muscle vibrations. First, we tested whether acoustic signals are similar in the field and in the laboratory, and discovered that field-produced rumbles are more acoustically and …

Comparisons Of Vcsel And Airs/Amsu-A On Water Vapor And Temperature In Hippo#1, Minghui Diao, Mark Zondlo, Loayeh Jumbah, Justin Sheffield, Eric Wood

Faculty Publications, Meteorology and Climate Science

No abstract available.

The Effect Of Zonally Asymmetric Ozone Heating On The Northern Hemisphere Winter Polar Stratosphere, J. P. Mccormack, T. R. Nathan, E. C. Cordero

Faculty Publications, Meteorology and Climate Science

[1] Previous modeling studies have found significant differences in winter extratropical stratospheric temperatures depending on the presence or absence of zonally asymmetric ozone heating (ZAOH), yet the physical mechanism causing these differences has not been fully explained. The present study describes the effect of ZAOH on the dynamics of the Northern Hemisphere extratropical stratosphere using an ensemble of free-running atmospheric general circulation model simulations over the 1 December - 31 March period. We find that the simulations including ZAOH produce a significantly warmer and weaker stratospheric polar vortex in mid-February due to more frequent major stratospheric sudden warmings compared to …

Fire Whirl Evolution Observed During A Valley Wind-Sea Breeze Reversal, Daisuke Seto, Craig B. Clements

Faculty Publications, Meteorology and Climate Science

This observational study documented the atmospheric environment of a prescribed fire conducted in a narrow valley when a small fire whirl developed during a mesoscale wind reversal. Based on analysis of in situ meteorological measurements, it is hypothesized that the fire whirl formed due to the presence of strong vertical wind shear caused by the interaction of a sea breeze front with a weaker up-valley wind. Vorticity generated by the interaction of the wind shear and the fire front was estimated to be ~0.2 s−1. Peak turbulence kinetic energy was caused by the wind shear rather than the buoyancy generated …

Calibration Of The Total Carbon Column Observing Network Using Aircraft Profile Data, D. Wunch, G. Toon, P. Wennberg, Steven Wofsy, B. Stephens, M. Fischer, O. Uchino, J. Abshire, P. Bernath, S. Biraud, J.-F. Blavier, C. Boone, K. Bowman, E. Browell, T. Campos, B. Connor, B. Daube, N. Deutscher, Minghui Diao, J. Elkins, C. Gerbig, E. Gottlieb, D. W. Griffith, D. Hurst, R. Jimenez, G. Keppel-Aleks, E. Kort, R. Macatangay, T. Machida, H. Matsueda, F. Moore, I. Morino, S. Park, J. Robinson, C. Roehl, Y. Sawa, V. Sherlock, C. Sweeney, T. Tanaka, M. Zondlo

Faculty Publications, Meteorology and Climate Science

The Total Carbon Column Observing Network (TCCON) produces precise measurements of the column average dry-air mole fractions of CO2, CO, CH4, N2O and H2O at a variety of sites worldwide. These observations rely on spectroscopic parameters that are not known with sufficient accuracy to compute total columns that can be used in combination with in situ measurements. The TCCON must therefore be calibrated to World Meteorological Organization (WMO) in situ trace gas measurement scales. We present a calibration of TCCON data using WMO-scale instrumentation aboard aircraft that measured profiles over four TCCON stations during 2008 and 2009. These calibrations are …

Chemistry–Climate Model Simulations Of Twenty-First Century Stratospheric Climate And Circulation Changes, Neal Butchart, I. Cionni, V. Eyring, T. G. Shepherd, D. W. Waugh, H. Akiyoshi, J. Austin, C. Brühl, M. P. Chipperfield, Eugene C. Cordero, M. Dameris, R. Deckert, S. Dhomse, S. M. Frith, R. R. Garcia, A. Gettelman, M. A. Giorgetta, D. E. Kinnison, F. Li, E. Mancini, S. Pawson, G. Pitari, D. A. Plummer, E. Rozanov, F. Sassi, J. F. Scinocca, K. Shibata, B. Steil, W. Tian

Faculty Publications, Meteorology and Climate Science

The response of stratospheric climate and circulation to increasing amounts of greenhouse gases (GHGs) and ozone recovery in the twenty-first century is analyzed in simulations of 11 chemistry–climate models using near-identical forcings and experimental setup. In addition to an overall global cooling of the stratosphere in the simulations (0.59 ± 0.07 K decade⁻¹ at 10 hPa), ozone recovery causes a warming of the Southern Hemisphere polar lower stratosphere in summer with enhanced cooling above. The rate of warming correlates with the rate of ozone recovery projected by the models and, on average, changes from 0.8 to 0.48 K decade …