Atmospheric Sciences Commons^™

Sparticus: Small Particles In Cirrus Science And Operations Plan, J. Mace, E. Jensen, G. Mcfarquhar, J. Comstock, T. Ackerman, David L. Mitchell, X. Liu, T. Garrett

Publications (E)

From a mass-weighted perspective, cirrus clouds exert an enormous influence on the radiative energy budget of the earth?s climate system. Owing to their location in the cold upper troposphere, cirrus can significantly reduce the outgoing longwave radiation while, at the same time, remaining relatively transmissive to solar energy. Thus, cirrus clouds are the only cloud genre that can exert a direct radiative warming influence on the climate system (Ackerman et al. 1988). It is not surprising, therefore, that general circulation models (GCMs) are especially sensitive to the presence of cirrus in the model atmosphere. Lohmann and Roeckner (1995), for instance, …

Analysis And Modeling Of Ducted And Evanescent Gravity Waves Observed In The Hawaiian Airglow, D. B. Simkhada, J. B. Snively, M. J. Taylor, S. J. Franke

Publications

Short-period gravity waves of especially-small horizontal scale have been observed in the Maui, Hawaii airglow. Typical small-scale gravity wave events have been investigated, and intrinsic wave propagation characteristics have been calculated from simultaneous meteor radar wind measurements. Here we report specific cases where wave structure is significantly determined by the local wind structure, and where wave characteristics are consistent with ducted or evanescent waves throughout the mesopause region. Two of the documented events, exhibiting similar airglow signatures but dramatically different propagation conditions, are selected for simple numerical modeling case studies. First, a Doppler-ducted wave trapped within relatively weak wind flow …

Droughtscape, Summer 2009, Kelly Smith

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

U.S. Drought Monitor Forum, 2009

El Niño Could Bring Wet Winter After Hot Summer

Around the World

Agriculture Hit Hard in California, Texas

Predictable Patterns in Missouri River Basin?

Seeking Low-Flow Effects in Colorado, Southeast

VegDRI Began Coast-to-Coast Coverage in May

Impact Of The Intraseasonal Variability Of Large-Scale Circulation Over The Western North Pacific On The Characteristics Of Tropical Cyclone Track, T. C. Chen, Shih-Yu (Simon) Wang, M. C. Yen, A. J. Clark

Plants, Soils, and Climate Faculty Publications

The life cycle of the Southeast Asian–western North Pacific monsoon circulation is established by the northward migrations of the monsoon trough and the western Pacific subtropical anticyclone, and is reflected by the intraseasonal variations of mo nsoon westerlies and trad e easterlies in the form of an east–west seesaw oscillation. In this paper, an effort is made to disclose the influence of this monsoon circulation on tropical cyclone tracks during its different ph ases using composite charts of large-scale circulation for certain types of tracks. A majority of straight-moving (recurving) tropical cyclones appear during weak (strong) monsoon west- erlies and …

Droughtscape, Spring 2009, Kelly Smith

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

U.S. Drought Monitor Publishes Map 500!

Weakening La Niña May Mean Relief for Texas

Upcoming Workshops

Drought Impacts Worst in California, Texas

CoCoRaHS to Request Drought Impact Data, Too

NDMC Adds Researcher

K-12 Students Learn About Drought

Assessment Of Weather Sensitivities And Air Force Weather (Afw) Support To Tactical Lasers In The Lower Troposphere, Francesco J. Echeverria

Theses and Dissertations

ATL scientists need to develop a full understanding of the interaction effects between a high-energy laser beam and the atmosphere through which it propagates. Achieving this understanding is important for many reasons. In particular, the high cost of DE weapons systems makes each propagation event expensive. Having an understanding of the atmosphere in which a high-energy laser propagates will increase efficiency and effectiveness of the ATL weapon system, which in turn will decrease cost of operation. A tool that allows for the ATL war-fighter to determine the atmospheric effects on laser propagation currently does not exist. This study creates a …

A System For Estimating Bowen Ratio And Evaporation From Waste Lagoons, Arturo I. Quintanar, Rezaul Mahmood, John H. Loughrin, Nanh Lovanh, Monica V. Motley

High Plains Regional Climate Center: Staff Publications

A low‐cost system was deployed above a swine waste lagoon to obtain estimates of Bowen ratios and characterize lagoon temperatures. The system consisted of humidity and temperature sensors and anemometers deployed above the lagoon, water temperature sensors, and a meteorological station located by the lagoon. To evaluate the system, data was analyzed from the 25th through 28th June 2007. Bowen ratios showed diurnal behavior near the lagoon surface characterized by negative values during day and positive ones at night. Latent (evaporation) and sensible heat fluxes were towards the atmosphere and the lagoon, respectively for most of the day. A diurnal …

Droughtscape, Winter 2009, Kelly Smith

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

Bastrop TX: Feb. 12 Central CA: Feb. 24, 26

La Niña May Keep West and Gulf Coast Dry

Big Canoes to Launch

2008 in Review

U.S. Feels Drought Impacts in 2008

NDMC Welcomes Widhalm, Sakamoto

Climate Modelers at Workshop Look to Sea Surface Temperatures for Drought Prediction

Ecosystem Jenga!, Natalie Umphlett, Tierney Brosius, Ramesh Laungani, Diandra L. Leslie-Pelecky

High Plains Regional Climate Center: Staff Publications

Students are often taught that ecosystems are "delicately balanced," But what. exactly, does this mean? How do we help students relate what they learn in the classroom about ecosystems to the world immediately around them?

As scientists who work closely with middle school students as part of a National Science Foundation-funded Graduate Fellows in K-12 Education program called Project Fulcrum. we have learned that abstract concepts, such as "delicately balanced ecosystem," are often not truly understood. We addressed this concern in a seventh-grade science classroom in Lincoln. Nebraska. by introducing students to locally threatened saline wetlands and the endangered Salt …

Numerical Simulations Of The Impacts Of The Saharan Air Layer On Atlantic Tropical Cyclone Development, Donglian Sun, K. M. Lau, Menas Kafatos, Z. Boybeyi, G. Leptoukh, C. Yang, Ruixin Yang

Mathematics, Physics, and Computer Science Faculty Articles and Research

In this study, the role of the Saharan air layer (SAL) is investigated in the development and intensification of tropical cyclones (TCs) via modifying environmental stability and moisture, using multisensor satellite data, long-term TC track and intensity records, dust data, and numerical simulations with a state-of-the-art Weather Research and Forecasting model (WRF). The long-term relationship between dust and Atlantic TC activity shows that dust aerosols are negatively associated with hurricane activity in the Atlantic basin, especially with the major hurricanes in the western Atlantic region. Numerical simulations with the WRF for specific cases during the NASA African Monsoon Multidisciplinary Analyses …

Two Contrasting Dust-Dominant Periods Over India Observed From Modis And Calipso Data, Ritesh Gautam, Zhaoyan Liu, Ramesh P. Singh, N. Christina Hsu

Mathematics, Physics, and Computer Science Faculty Articles and Research

Each year, prior to the onset of the Indian Summer Monsoon, the Gangetic Plains (GP), bounded by the high-altitude Himalayan mountains, are strongly influenced by the transport of dust outbreaks originating in the northwestern desert in India (known as the Thar Desert). Dust particles constitute the bulk of the regional aerosol loading which peaks annually during the pre-monsoon season. This paper integrates observations from space-borne sensors, namely MODIS and CALIPSO, together with ground sunphotometer measurements, to infer dust loading in the pre-monsoon aerosol build-up over source and sink regions in northern India. Detailed aerosol characterization from the synergetic observational assessment …

Validation Of Modis Terra, Airs, Ncep/Doe Amip-Ii Reanalysis-2, And Aeronet Sun Photometer Derived Integrated Precipitable Water Vapor Using Ground-Based Gps Receivers Over India, Anup K. Prasad, Ramesh P. Singh

Mathematics, Physics, and Computer Science Faculty Articles and Research

Water vapor is an important and highly variable constituent in time and space; the knowledge of its variability is important in climate studies. In India, the ground observations of water vapor using conventional methods such as radiosonde are limited. In this paper, a comparison of hourly estimates of total column water vapor from Global Positioning System (GPS) with multisensor satellite is presented over three stations. We show quantitatively seasonal and monthly dependency of bias, standard deviation, root mean square error (RMSE), and the correlation coefficient between the water vapor data sets. The GPS and Aerosol Robotic Network (AERONET) water vapor …

Enhanced Pre-Monsoon Warming Over The Himalayan-Gangetic Region From 1979-2007, Ritesh Gautam, N. C. Hsu, K. M. Lau, S.-C. Tsay, Menas Kafatos

Mathematics, Physics, and Computer Science Faculty Articles and Research

Fundamental to the onset of the Indian Summer Monsoon is the land-sea thermal gradient from the Indian Ocean to the Himalayas-Tibetan Plateau (HTP). The timing of the onset is strongly controlled by the meridional tropospheric temperature gradient due to the rapid premonsoon heating of the HTP compared to the relatively cooler Indian Ocean. Analysis of tropospheric temperatures from the longest available record of microwave satellite measurements reveals widespread warming over the Himalayan-Gangetic region and consequent strengthening of the land-sea thermal gradient. This trend is most pronounced in the pre-monsoon season, resulting in a warming of 2.7 C in the 29-year …

Inter-Continental Transport Of Dust And Pollution Aerosols Across Alexandria, Egypt, Hesham El-Askary, R. Farouk, C. Ichoku, Menas Kafatos

Mathematics, Physics, and Computer Science Faculty Articles and Research

The flow of pollutants from Europe and desert dust to Europe from the Sahara desert both affects the air quality of the coastal regions of Egypt. As such, measurements from both ground and satellite observations assume great importance to ascertain the conditions and flow affecting the Nile Delta and the large city of Alexandria. We note that special weather conditions prevailing in the Mediterranean Sea result in a westerly wind flow pattern during spring and from North to South during the summer. Such flow patterns transport dust-loaded and polluted air masses from the Sahara desert and Europe, respectively, through Alexandria, …

Cirene Air-Sea Interactions In The Seychelles-Chagos Thermocline Ridge Region, J. Vialard, J. P. Duvel, M. J. Mcphaden, P. Bouruet-Aubertot, B. Ward, E. Key, D. Bourras, R. Weller, P. Minnett, A. Weil

OES Faculty Publications

A field experiment in the southwestern Indian Ocean provides new insights into ocean-atmosphere interactions in a key climatic region.

Droughtscape, Fall 2008, Kelly Smith

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

Washington Workshops Scheduled for November

Look for Warm West, Rainy Gulf, Easing Drought

New Drought Monitor Authors Profiled

Drought Impact Awareness Growing: Weather Forecast Offices, Geographers Highlight Issue

NDMC Takes on New Projects

Hundreds+ See NDMC at Ag Trade Show

NDMC Welcomes New Employees

Droughtscape, Fall 2008, Kelly Smith

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

Washington Workshops Scheduled for November

Look for Warm West, Rainy Gulf, Easing Drought

New Drought Monitor Authors Profiled

Drought Impact Awareness Growing: Weather Forecast Offices, Geographers Highlight Issue

NDMC Takes on New Projects

Hundreds+ See NDMC at Ag Trade Show

NDMC Welcomes New Employees

The Contribution Of Advective Fluxes To Net Ecosystem Exchange In A High-Elevation, Subalpine Forest, Chuixiang Yi, Dean E. Anderson, Andrew A. Turnipseed, Sean P. Burns, Jed P. Sparks, David I. Stannard, Russell K. Monson

Publications and Research

The eddy covariance technique, which is used in the determination of net ecosystem CO₂ exchange (NEE), is subject to significant errors when advection that carries CO₂ in the mean flow is ignored. We measured horizontal and vertical advective CO₂ fluxes at the Niwot Ridge AmeriFlux site (Colorado, USA) using a measurement approach consisting of multiple towers. We observed relatively high rates of both horizontal (F_hadv) and vertical (F_vadv) advective fluxes at low surface friction velocities (u_*) which were associated with downslope katabatic flows. We observed that F_hadv was confined to …

Droughtscape, Summer 2008, Kelly Smith

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

VegDRI Expands West

Spring Rains Ease Drought But CA Still Dry

Scholar Donates Books

NDMC Welcomes Employees Bathke, Nothwehr

Latest Workshop Info Up

State Lawmakers to Focus on Drought Planning

Decadal Variation -- Clues to Droughts and Floods?

Climate Change Education And The Ecological Footprint, Eugene C. Cordero, Anne Marie Todd, Diana Abellera

Faculty Publications, Meteorology and Climate Science

Global warming has become one of the most important scientific, political, and social issues of our era. In designing an effective mitigation strategy, it is clear that public education must play an important role. This study looks at various components of climate change literacy within a cohort of university students and investigates the impact of action-oriented learning on student understanding. Results from questionnaires given to primarily nonscience students enrolled in weather and climate courses are used to examine student knowledge of climate change. In agreement with prior research, this study finds that signif icant student misconceptions exist regarding the causes …

The Katrina Project, Alison Traver

Senior Honors Projects

No abstract provided.

Droughtscape, Spring 2008, Kelly Smith

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

San Angelo, April 24

Winter Sees Little Change in U.S. Drought

News Stories Reveal Array of Mitigation Strategies

NIDIS Wants You!

Sea Surface Temperatures Can Help Predict Drought

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First Observations Of Turbulence Generated By Grass Fires, Craig Clements, Shiyuan Zhong, Xindi Bian, Warren Heilman, Daewon Byun

Faculty Publications, Meteorology and Climate Science

Wildland fires radically modify the atmospheric boundary layer by inducing strong fire-atmosphere interactions. These interactions lead to intense turbulence production in and around the fire front. Two field experiments were conducted in tall-grass fuels to quantify turbulence generation during the passage of wind-driven fire fronts. Observations showed that the measured turbulence generated by the fires was five times greater than the turbulence in the ambient environment. The production of the turbulence at the surface near the fire front was caused by increased variance of the ambient wind, while the buoyancy was strongest at higher levels within the fire plume. Immediately …

Metcrax 2006 - Meteorological Experiments In Arizona's Meteor Crater, C. David Whiteman, Sebastian Hoch, Maura Hahnenberger, Andreas Muschinski, Vincent Hohreiter, Mario Behn, Yonghum Cheon, Sharon Zhong, Wenqing Yao, David Fritts, Craig Clements, Thomas Horst, William Brown, Steven Oncley

Faculty Publications, Meteorology and Climate Science

The Meteor Crater Experiment (METCRAX 2006) was conducted in October 2006 at Arizona's Meteor Crater to investigate stable boundary layer evolution in a topographically uncomplicated basin surrounded by the nearly homogeneous plain of the Colorado Plateau. The two goals of the experiment were 1) to investigate the microscale and mesoscale structure and evolution of the stable boundary layer in the crater and its surroundings and 2) to determine whether atmospheric seiches or standing waves are produced inside the crater. This article provides an overview of the scientific goals of the experiment; summarizes the research measurements, the crater topography, and the …

Sampling Of Malodorous Compounds In Air Using Stir Bar Sorbtive Extraction, John H. Loughrin, Nanh Lovanh, Arturo I. Quintanar, Rezaul Mahmood

High Plains Regional Climate Center: Staff Publications

Twisters, (poly)‐dimethylsiloxane‐coated magnetic stir bars, were used to measure compounds typical of swine manure malodor in air. In initial experiments, a time to achieve equilibrium was determined by preloading the stir bars with ten compounds with a range of volatilities and polarities and then monitoring their loss. The rate of loss was dependent on compound volatility, and the time for equilibrium to be attained varied widely, from 22 min for phenol to 210 min for skatole. To test whether the Twisters would respond linearly over a range of concentrations, the stir bars were placed in vented jars with solutions of …

Droughtscape, Winter 2008, Kelly Smith

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

Now Up & On-Line:

Winter 2008 Outlook and Oct.-Dec. ’07 Summary

NDMC Experts Serve as Resource for Media

Drought Hits Ag and Urban Interests in 2007

Climatological Summary of Drought in 2007

NDMC Welcomes Data Miner Bo Zhang

New Grant Awards

Characterization And Analysis Of Hailstorms In The Northern Great Plains, Thomas Sando

The Journal of Undergraduate Research

Hail is a meteorological occurrence that appears frequently during spring and summer across the Northern Great Plains. This paper first characterizes patterns associated with reported hail events occurring within a five-state region (North Dakota, Minnesota, South Dakota, Iowa, and Nebraska) from 2000-2006 using records taken from the National Climatic Data Center (NCDC) Severe Storms database. Patterns of interest include the seasonality of hail activity for each state and across the region, observational bias in the reporting of hailstone size, and temporal trends in the number of hail reports across the region and in each state. This paper then explores a …

Technical Note: Molecular Characterization Of Aerosol-Derived Water Soluble Organic Carbon Using Ultrahigh Resolution Electrospray Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry, A. S. Wozniak, J. E. Bauer, R. L. Sleighter, R. M. Dickhut, Patrick Hatcher

Chemistry & Biochemistry Faculty Publications

Despite the acknowledged relevance of aerosol-derived water-soluble organic carbon (WSOC) to climate and biogeochemical cycling, characterization of aerosol WSOC has been limited. Electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) was utilized in this study to provide detailed molecular level characterization of the hi(,h molecular weight (HMW; m/z>223) component of aerosol-derived WSOC collected from rural sites in Virginia and New York, USA. More than 3000 peaks were detected by ESI FT-ICR MS within a m/z range of 223-600 for each sample. Approximately 86% (Virginia) and 78% (New York) of these peaks were assigned molecular formulas …

Contrasting The 2007 And 2005 Hurricane Seasons: Evidence Of Possible Impacts Of Saharan Dry Air And Dust On Tropical Cyclone Activity In The Atlantic Basin, D. Sun, K. M. Lau, Menas Kafatos

Mathematics, Physics, and Computer Science Faculty Articles and Research

In this study, we provide preliminary evidence of possible modulation by Saharan dust of hurricane genesis and intensification, by contrasting the 2007 and 2005 hurricane seasons. It is found that dust aerosol loadings over the Atlantic Ocean are much higher in 2007 than in 2005. The temperature difference between 2007 and 2005 shows warming in the low-middle troposphere (900–700 hPa) in the dusty region in the eastern North Atlantic, and cooling in the Main Development Region (MDR). The humidity (wind) differences between 2007 and 2005 indicate significant drying (subsidence) in the Western North Atlantic (WNA) in 2007. The drier air …

Forcing Mechanisms For Washoe Zephyr - A Daytime Downslope Wind Phenomenon In The Great Basin East Of The Sierra Nevada, Shiyuan Zhong, Ju Li, Craig Clements, Stephan Dewekker, Xindi Bian

Faculty Publications, Meteorology and Climate Science

This paper investigates the formation mechanisms for a local wind phenomenon known as Washoe Zephyr that occurs frequently in the lee of the Sierra Nevada. Unlike the typical thermally driven slope flows with upslope wind during daytime and downslope at night, the Washoe Zephyr winds blow down the lee slopes of the Sierra Nevada in the afternoon against the local pressure gradient. Long-term hourly surface wind data from several stations on the eastern slope of the Sierra Nevada and rawinsonde sounding data in the region are analyzed and numerical simulations are performed to test the suggested hypotheses on the formation …