Meteorology Commons^™

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 …

Diagnosis Of The July 6, 2002 Ogallala, Nebraska Flash Flood, David B. Radell, Mark R. Anderson, John W. Stoppkotte, James R. Mccormick

Department of Earth and Atmospheric Sciences: Faculty Publications

During the early morning hours of 6 July 2002, a mesoscale convective system (MCS) traversed southwestern Nebraska and produced more than 40 cm of precipitation, resulting in a flash flood that closed Interstate 80 and caused one fatality near Ogallala, Nebraska. Regional climatology yields that this flash flood ranked first in precipitation amount for a 24 hour period over the past one hundred years. Synoptic and mesoscale features similar to other flash flooding events and conducive to extremely heavy precipitation were in place over the Central Plains, including a weak upper level ridge, high precipitable water values (180% of normal), …

Droughtscape, Fall 2007, National Drought Mitigation Center

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

Fall 2007 Outlook

Diverse Impacts Reported in Summer of 2007

Decadal Climate Cycles Hold Predictive Potential

Drought Experts Take Roadmap to Congress

NDMC Research Updates

Multimodel Projections Of Stratospheric Ozone In The 21st Century, V. Eyring, D. W. Waugh, G. E. Bodeker, Eugene C. Cordero, H. Akiyoshi, J. Austin, S. R. Beagley, B. A. Boville, P. Braesicke, C. Brühl, N. Butchart, M. P. Chipperfield, M. Dameris, R. Deckert, M. Deushi, S. M. Frith, R. R. Garcia, A. Gettelman, M. A. Giorgetta, D. E. Kinnison, E. Mancini, E. Manzini, D. R. Marsh, S. Matthes, T. Nagashima, P. A. Newman, J. E. Nielsen, S. Pawson, G. Pitari, D. A. Plummer, E. Rozanov, M. Schraner, J. F. Scinocca, K. Semeniuk, T. G. Shepherd, K. Shibata, B. Steil, R. S. Stolarski, W. Tian, M. Yoshiki

Faculty Publications, Meteorology and Climate Science

[1] Simulations from eleven coupled chemistry-climate models (CCMs) employing nearly identical forcings have been used to project the evolution of stratospheric ozone throughout the 21st century. The model-to-model agreement in projected temperature trends is good, and all CCMs predict continued, global mean cooling of the stratosphere over the next 5 decades, increasing from around 0.25 K/decade at 50 hPa to around 1 K/decade at 1 hPa under the Intergovernmental Panel on Climate Change (IPCC) Special Report on Emissions Scenarios (SRES) A1B scenario. In general, the simulated ozone evolution is mainly determined by decreases in halogen concentrations and continued cooling of …

Droughtscape, Summer 2007, National Drought Mitigation Center

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

Summer 07 Outlook

Hayes Named Director of NDMC

NDMC & UN Plan for Drought

Book Review: The Worst Hard Time

Drought Tools Workshops Underway

U.S. Drought Monitor Forum October 10-11, 2007 Portland, Oregon

Droughtscape, Spring 2007, National Drought Mitigation Center

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

2007 Spring Drought Outlook & Winter Summary

VegDRI Expands to 15 States, Refines Views

DroughtScape

State Spotlight: Utah

International Panel Foresees Drought as Part of Climate Change

NIDIS Portal Advancing

An Ozone-Modified Refractive Index For Vertically Propagating Planetary Waves, Terrence R. Nathan, Eugene C. Cordero

Faculty Publications, Meteorology and Climate Science

[1] An ozone-modified refractive index (OMRI) is derived for vertically propagating planetary waves using a mechanistic model that couples quasigeostrophic potential vorticity and ozone volume mixing ratio. The OMRI clarifies how wave-induced heating due to ozone photochemistry, ozone transport, and Newtonian cooling (NC) combine to affect wave propagation, attenuation, and drag on the zonal mean flow. In the photochemically controlled upper stratosphere, the wave-induced ozone heating (OH) always augments the NC, whereas in the dynamically controlled lower stratosphere, the wave-induced OH may augment or reduce the NC depending on the detailed nature of the wave vertical structure and zonal mean …

Agricultural Climatology, Kenneth G. Hubbard

High Plains Regional Climate Center: Staff Publications

With the diversification of the U.S. economy over the past century, agriculture has changed. We can say the farm sizes have increased over time, the number of farmers and those employed in farming have decreased over time, and as the economy has grown the relative contribution of agriculture to the total economy has decreased due to growth in other sectors. The farm prices have not changed significantly over many years while costs for energy, machinery, and land have generally increased. The combination of these factors has generally narrowed the profit margin and the highest productivity will no longer ensure the …

Droughtscape, Winter 2007, Kelly Smith

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

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Policy Update: NIDIS is Law. What’s Next?

What Would You Like to See?

TX, OK, Plains, Southwest Hardest Hit in 2006

Climatologically Speaking, How Bad Was It?

State Spotlight: Arizona

Drought Decision-Support Tools Evolving

Yucca Mountain Climate: Past, Present, And Future, Saxon E. Sharpe

Publications (YM)

Evaluation of modern climate is necessary to relate climatic events to near-surface processes such as infiltration, runoff, and evapotranspiration. Modern climate information also aids in environmental analyses of repository design facilities and atmospheric dispersion models. Evaluation of past climate regimes, particularly temperature and precipitation, is needed to assess the relation of past climate to past hydrologic conditions. Estimates of potential future climate and hydrology are needed to evaluate repository performance.

Stratospheric Variability And Trends In Models Used For The Ipcc Ar4, P. M. De F. Forster, Eugene Cordero

Faculty Publications, Meteorology and Climate Science

Atmosphere and ocean general circulation model (AOGCM) experiments for the Intergovernmental Panel on Climate Change Fourth Assessment Report (AR4) are analyzed to better understand model variability and assess the importance of various forcing mechanisms on stratospheric trends during the 20th century. While models represent the climatology of the stratosphere reasonably well in comparison with NCEP reanalysis, there are biases and large variability among models. In general, AOGCMs are cooler than NCEP throughout the stratosphere, with the largest differences in the tropics. Around half the AOGCMs have a top level beneath ~2 hPa and show a significant cold bias in their …

Assessment Of Temperature, Trace Species, And Ozone In Chemistry-Climate Model Simulations Of The Recent Past, V. Eyring, N. Butchart, D. W. Waugh, H. Akiyoshi, J. Austin, S. Bekki, G. E. Bodeker, B. A. Boville, C. Brühl, M. P. Chipperfield, E. Cordero, M. Dameris, M. Deushi, V. E. Fioletov, S. M. Frith, R. R. Garcia, A. Gettelman, M. A. Giorgetta, V. Grewe, L. Jourdain, D. E. Kinnison, E. Mancini, E. Manzini, M. Marchand, D. R. Marsh, T. Nagashima, P. A. Newman, J. E. Nielsen, S. Pawson, G. Pitari, D. A. Plummer, E. Rozanov, M. Schraner, T. G. Shepherd, K. Shibata, R. S. Stolarski, H. Struthers, W. Tian, M. Yoshiki

Faculty Publications, Meteorology and Climate Science

[1] Simulations of the stratosphere from thirteen coupled chemistry-climate models (CCMs) are evaluated to provide guidance for the interpretation of ozone predictions made by the same CCMs. The focus of the evaluation is on how well the fields and processes that are important for determining the ozone distribution are represented in the simulations of the recent past. The core period of the evaluation is from 1980 to 1999 but long-term trends are compared for an extended period (1960–2004). Comparisons of polar high-latitude temperatures show that most CCMs have only small biases in the Northern Hemisphere in winter and spring, but …

Loop Current Warming By Hurricane Wilma, Lie-Yauw Oey, Tal Ezer, Dong-Ping Wang, S. J. Fan, Xun-Qiang Yin

CCPO Publications

Hurricanes mix and cool the upper ocean, as shown here in observations and modeling of the Caribbean Sea and the Gulf of Mexico during the passage of hurricane Wilma. Curiously, the upper ocean around the Loop Current warmed prior to Wilma's entrance into the Gulf. The major cause was increased volume and heat transports through the Yucatan Channel produced by storm-induced convergences in the northwestern Caribbean Sea. Such oceanic variability may have important impacts on hurricane predictions.

A New Pathway For Communicating The 11-Year Solar Cycle Signal To The Qbo, Eugene C. Cordero, Terrence R. Nathan

Faculty Publications, Meteorology and Climate Science

[1] The response of the equatorial quasi-biennial oscillation (QBO) to zonal-mean ozone perturbations consistent with the 11-year solar cycle is examined using a 2 1/2 dimensional model of the tropical stratosphere. Unique to this model are wave-ozone feedbacks, which provide a new, nonlinear pathway for communicating solar variability effects to the QBO. Model simulations show that for zonal-mean ozone perturbations representative of solar maximum (minimum), the diabatic heating due to the wave-ozone feedbacks is primarily responsible for driving a slightly stronger (weaker) QBO circulation and producing a slightly shorter (longer) QBO period. These results, which are explained via an analytical …

Hydrographic And Biological Changes In The Taiwan Strait During The 1997-1998 El Niño Winter, S. Shang, C. Zhang, H. Hong, Q. Liu, G. T. F. Wong, C. Hu, B. Huang

OES Faculty Publications

During the 1997–1998 El Niño event, the average sea surface temperature (SST) in the Taiwan Strait (TWS) in the winter was ~1.4°C higher than that of the winter climatological mean. The areal ratio of the warm water (≥2°C above the regional mean) to the cold water (≥2°C below the regional mean) in the TWS increased by 25% while the area of the eutrophic water (chlorophyll a >1 mg m^-3) was halved. Field observations also indicate that the mixed layer in the TWS became more nutrient-poor during this winter. These observations are consistent with a diminished advection of the …

Evaluating Spatial Variability Of Precipitation In Kentucky With Exploratory Data Analysis, Daniel Taylor

Masters Theses & Specialist Projects

Spatial variability of precipitation is examined over the state of Kentucky and surrounding areas. The study focuses on the analysis of monthly precipitation totals from the period of 1961-2000. The purpose of the study is to develop a set of indices to represent the spatial variability of the study area for a given month. Various exploratory data analysis methods such as variography, kriging, and cluster analysis were used. The study attempts to quantify the second order (local) effects of the spatial variation of precipitation as a means to provide insight into the prediction of precipitation randomness. This task can be …

An Analysis Of Simulated Long-Term Soil Moisture Data For Three Land Uses Under Contrasting Hydroclimatic Conditions In The Northern Great Plains, Rezaul Mamood, Kenneth G. Hubbard

High Plains Regional Climate Center: Staff Publications

Soil moisture (SM) plays an important role in land surface and atmosphere interactions. It modifies energy balance near the surface and the rate of water cycling between land and atmosphere. The lack of observed SM data prohibits understanding of SM variations at climate scales under varying land uses. However, with simulation models it is possible to develop a long-term SM dataset and study these issues. In this paper a water balance model is used to provide a quantitative assessment of SM climatologies for three land uses, namely, irrigated corn, rain-fed corn, and grass, grown under three hydroclimatic regimes in Nebraska. …

Climate: Past, Present, And Future, Saxon E. Sharpe, Rick Forester, Amy J. Smiecinski

Publications (YM)

Climatology and meteorology studies in the Yucca Mountain area have resulted in the following key observations and conclusions: • The present-day arid climate of the Yucca Mountain area can be understood in terms of global-scale atmospheric circulation and regional to-local physiographic features. In general terms, the area is under the influence of mid-latitude westerly winds and associated storm systems during the cool part of the year and and is under the influence of moist air advected from the eastern tropical Pacific Ocean and Gulf of California during the summer. Temperature and precipitation data from Nevada regions 3 and 4 (southern …

Natural Disasters: An Integrated Curriculum Unit, Grades 3-5, Institute For The Development Of Gifted Education, Ricks Center For Gifted Children, University Of Denver

Ricks Curriculum Units Series

An integrated curriculum is an instructional approach that connects the disciplines to an underlying theme or topic. Immersing students in an integrated-thematic unit provides the backdrop for experiences to occur across the disciplines. Shaping coursework around integrated themes is especially appropriate for gifted students, however using an integrated-thematic curriculum is appropriate for all learners as it develops students' abilities to make connections, to solve problems by looking at multiple perspectives, and to integrate information from different fields of experience. An integrated-thematic curriculum permits students to be active participants in their own learning as they design their own explorations and take …

Transport Out Of The Antarctic Polar Vortex From A Three-Dimensional Transport Model, Shuhua Li, Eugene Cordero, David J. Karoly

Faculty Publications, Meteorology and Climate Science

[1] A three-dimensional chemical transport model is utilized to study the transport out of the Antarctic polar vortex during the southern hemisphere spring. On average, over five consecutive years between 1993 and 1997, horizontal transport out of the vortex into the midlatitude stratosphere is smaller than vertical transport into the troposphere. However, there is significant interannual variability in the magnitude of mass exchange, which is related to year-to-year fluctuations in planetary wave activity. In 1994 the net loss of the vortex tracer mass in September is similar to that in October. However, the relative mass flux entering the midlatitude stratosphere …

An Examination Of Anomalously Low Column Ozone In The Southern Hemisphere Midlatitudes During 1997, Eugene C. Cordero, Terrence R. Nathan

Faculty Publications, Meteorology and Climate Science

[1] Observations from both ground-based and satellite instruments show record low column ozone abundance between 20°S and 40°S during 1997. The 1997 monthly averaged column ozone from the Total Ozone Mapping Spectrometer (TOMS) is up to 25 Dobson units (DU) lower than the TOMS climatological mean (1979–1996) and up to 20 DU below the previous record low values. Observations from the Halogen Occultation Experiment show that below average ozone concentrations during 1997 were confined primarily to the lower stratosphere. Residual circulation statistics calculated from the United Kingdom Meteorological Office temperature analyses indicate that circulation anomalies during 1997 can account for …

Is The Ozone Hole Over Your Classroom?, Eugene Cordero

Faculty Publications, Meteorology and Climate Science

First year university science students are surveyed about their understanding of the ozone layer, ozone depletion and the effect of ozone depletion on Australia. Although students seem to understand the basic function of the ozone layer, over 65% of students incorrectly believe that the ozone hole is over Australia, and over 90% of students incorrectly believe that the ozone hole is present during the summer. Together these ideas seem to explain why nearly 75% of students blame the ozone hole for Australia’s high rate of skin cancer. Survey results also indicate that students seem confused about global warming, and the …

Land Use Change And Modification Of Near-Surface Thermal Records In The Northern Great Plains, Rezaul Mahmood, Ken Hubbard, Christy Carlson

High Plains Regional Climate Center: Staff Publications

The North American Great Plains have experienced a rapid overturning of natural grasslands to agricultural land use over the last century. Moreover, in some areas more than 80% of the land use has changed from dry land to irrigated agriculture during the second half of the twentieth century. It is speculated that these changes have modified near-surface atmospheric condition and our modeling study seems to support this. To identify changes in land surface- atmospheric modifications we have applied a soil moistureenergy balance model at three locations in Nebraska: Mead, York, and McCook. The model was applied for three land uses …

Ozone And Tracer Transport Variations In The Summer Northern Hemisphere Stratosphere, E. C. Cordero, S. R. Kawa

Faculty Publications, Meteorology and Climate Science

Constituent observations from the Upper Atmosphere Research Satellite (UARS) in combination with estimates of the residual circulation are used to examine the transport and chemical budgets of HF, CH₄ and O₃ in the summer Northern Hemisphere. Budget calculations of HF, CH₄ and O₃ show that the transport tendency due to the residual circulation increases in magnitude and is largely opposed by eddy motions through the summer months. Ozone budget analyses show that between 100 and 31 hPa, the magnitudes of the mean circulation and eddy transport terms increase through the summer months, producing tendencies that are …

A Model Of Precipitation Rates In Kentucky, 1965-1996, Kevin Cary

Masters Theses & Specialist Projects

Hourly precipitation data from thirty cooperative stations in Kentucky from 1965 to 1996 were used to determine the diurnal distribution of precipitation rates. Descriptive summaries for the diurnal distribution for each climate division in Kentucky and for Kentucky as a whole were calculated. In each case, the trends were similar. Precipitation rates increased into the afternoon and then decreased until sunrise. A stochastic model was developed to estimate mean seasonal precipitation rates in Kentucky by using regional and localized parameters. More than half of the variation (r2 = 0.57) in precipitation rates can be explained by the following variables: 1) …

The Influence Of Wave– And Zonal Mean–Ozone Feedbacks On The Quasi-Biennial Oscillation, Eugene Cordero, Terrence R. Nathan

Faculty Publications, Meteorology and Climate Science

The effects of wave and zonal mean ozone heating on the evolution of the quasi-biennial oscillation (QBO) are examined using a two-dimensional mechanistic model of the equatorial stratosphere. The model atmosphere is governed by coupled equations for the zonal mean and (linear) wave fields of ozone, temperature, and wind, and is driven by specifying the amplitudes of a Kelvin wave and a Rossby–gravity wave at the lower boundary. Wave–mean flow interactions are accounted for in the model, but not wave–wave interactions.

A reference simulation (RS) of the QBO, in which ozone feedbacks are neglected, is carried out and the results …

Effects Of Planetary Wave-Breaking On The Seasonal Variation Of Total Column Ozone, Terrence R. Nathan, Eugene C. Cordero, Long Li, Donald J. Wuebbles

Faculty Publications, Meteorology and Climate Science

The effects of planetary wave breaking on the seasonal variation of total column ozone are investigated using a zonally averaged chemical-radiative-transport model of the atmosphere. The planetary wave breaking effects of zonal wavenumbers k=1 and k=2 are significant in the middle latitude stratosphere during Northern Hemisphere (NH) winter, whereas only wave k=1 is important during Southern Hemisphere (SH) winter. The mixing and induced meridional circulation due to the planetary wave breaking increases the seasonal variation of total column ozone in NH (SH) middle latitudes by ∼20% (∼10%).

Estimating The Probability Of Severe Convective Storms: A Local Perspective For The Central And Northern Plains, Preston W. Leftwich Jr.

National Oceanographic and Atmospheric Administration: Technical Reports and Related Materials

Summary and Conclusions

A procedure to estimate probabilities of the occurrence of severe convective storms within local areas has been described. Probabilities were based on a simulated climatology and the relative frequency of severe convective events when a selected site was contained within an operational Outlook or Watch. Combined data from five local areas were used to develop a general model for local probabilities within the central and northern Plains region. Attachment of probabilities to specific products placed values within a framework familiar to both forecasters and "end-users." Application of results in an operational scenario demonstrated representative local probabilities and …

Africa: An Integrated Curriculum Unit, Grades 2-4, Institute For The Development Of Gifted Education, Ricks Center For Gifted Children, University Of Denver

Ricks Curriculum Units Series

An integrated curriculum is an instructional approach that connects the disciplines to an underlying theme or topic. Immersing students in an integrated-thematic unit provides the backdrop for experiences to occur across the disciplines. Shaping coursework around integrated themes is especially appropriate for gifted students, however using an integrated-thematic curriculum is appropriate for all learners as it develops students' abilities to make connections, to solve problems by looking at multiple perspectives, and to integrate information from different fields of experience. An integrated-thematic curriculum permits students to be active participants in their own learning as they design their own explorations and take …

Frontogenesis In The North Pacific Oceanic Frontal Zones--A Numerical Simulation, Michael S. Dinniman, Michele M. Rienecker

CCPO Publications

A primitive equation model [Geophysical Fluid Dynamics Laboratory's (GFDL's) MOM 2] with one degree horizontal resolution is used to simulate the seasonal cycle of frontogenesis in the subarctic frontal zone (SAFZ) and the subtropical frontal zone (STFZ) of the North Pacific Ocean. The SAFZ in the model contains deep (greater than 500 m in some places) regions with seasonally varying high gradients in temperature and salinity. The gradients generally weaken toward the east. The STFZ consists of a relatively shallow (less than 200 m in most places) region of high gradient in temperature that disappears in the summer/fall. The high …