Gregory D. Bierly

Mineralogical characterization and transport pathways of dune sand using Landsat TM data, Wahiba Sand Sea, Sultanate of Oman

Sand samples and Landsat imagery were used to characterize the spatial distribution of sand mineralogy, and to evaluate potential sources and transport pathways of sediment in the Wahiba Sand Sea in the Sultanate of Oman. Landsat TM data were useful in the geomorphic interpretation of a desert, aeolian environment to distinguish the mineralogies found in the Wahiba area, and in extending the identification of sand mineralogy beyond the point-specific grid produced from field sampling. The Wahiba Sand Sea has been previously divided into upper (north and higher in elevation) and lower (south and lower in elevation) portions, based on dune morphology. Large-scale spatial distributions of mineral composition follow a similar pattern to that of the geomorphic regions within the dune field. Field and Landsat TM data suggests the upper Wahiba is comprised of well-mixed carbonate and quartz sand with some areas of significant mafic content. Surface sand in the eastern and western margins of the upper Wahiba originate from the lower Wahiba and from local wadis. Sand in the lower Wahiba was likely derived from southern sabkhas and the coastal area and is quartz-rich with isolated locations of carbonate-rich sand. We suggest that these carbonate-rich patches in the lower Wahiba were derived from reworked aeolianites (lithofied sand dunes) which underlie most of the sand sea, and not directly from the coast, as previously reported.

A long-term climatology of southerly and northerly low-level jets for the central United States

A forty-year (1961–2000) climatology of southerly and northerly low-level jets (LLJs) was prepared from twice-daily rawinsonde observations for thirty-six stations in the central United States. Although there is extensive literature on southerly jets, their spatial variability has received little attention. Furthermore, there is a paucity of studies examining any aspects of northerly LLJs. Thus, the motivation for developing the climatology was to (1) examine in greater detail the spatial variation of LLJ characteristics across the central United States, (2) better document the nature of northerly LLJs, (3) provide a baseline for evaluating potential future changes in LLJ frequency and characteristics, and (4) assess through comparisons with previous studies what aspects of LLJs in the central United States remain poorly understood. The climatology is a substantial temporal and spatial expansion of previous studies and provides a more thorough description of the spatial variability of LLJs in terms of frequency, direction, speed, and elevation at annual, seasonal, and daily time scales. The complex spatial variations of LLJ characteristics in the central United States are summarized by seven objectively defined regions within the central United States with similar jet characteristics. These regions (Central Plains, Upper Midwest, East Central, Southeast, South Texas/Western Gulf, Foothills, and High Plains) vary in shape and extent by season and are indicative of the varying influence of different forcing mechanisms for LLJ formation. Comparison of the findings of this study with those of previous climatological analyses suggests that many of the characteristics of LLJs in the central United States are still incompletely documented and understood.

Structural and Compositional Change in Geography Graduate Programs in the United States: 1991–2001*

This paper presents an accounting of observed shifts within the structure and composition of geography graduate programs between 1991 and 2001. Using the AAG Guide to Programs, the study details how geographys primary divisions and areas of specialization have changed based on several parameters. These parameters include: department name, total tenure track lines, tenure track lines by major division (macrospecialization), tenure tracks by selected research areas (microspecialization), faculty rank, and degree programs. Using descriptive statistics, the paper identifies the structural implications of retirement in recent years, notes the emergence of new research areas (at both the macro- and microlevel), charts the expansion of traditional geography graduate programs, and the creation of new geography degree programs. The trajectory of the discipline is positive and growth continues. When and where reductions have been observed, the demographic transition of the professoriate is often an issue. Despite this inevitable transition, the growth and expansion of graduate programs continues and the overall pace observed is encouraging.

A Composite Analysis of Airstreams within Cold-Season Colorado Cyclones

Relative wind isentropic analysis was employed to investigate the evolution of airstreams and airstream boundaries within midlatitude cyclones that formed in the Colorado cyclogenesis region of the United States. This study attempts to verify and expand upon existing conceptual models of three-dimensional airflow, while describing how such models vary at different times during cyclone development and when the intensification history of the storm is considered. Forty-nine cyclone events were first divided into three categories: earlydeveloping cyclones (those that intensify with 24 h of cyclogenesis), late-developing cyclones (those that intensify 24‐48 h after cyclogenesis), and nondeveloping cyclones (those that either display little change in intensity or weaken with time). Composite isentropic surfaces for multiple levels (315‐290 K, separated by 5 K) were constructed by cyclone category for six 12-h time periods within the cyclone life cycle. Three distinct airstreams and four types of airstream boundaries were identified on the composite isentropic surfaces. Two of the airstreams closely resemble the ‘‘drystream’’ and ‘‘warm conveyor belt (WCB)’’ described in previous studies. The third airstream is referred to here as the cyclonically turning moist airstream (CMA). Until approximately 24 h after cyclogenesis, the CMA and WCB originate at similar latitudes although the CMA occurs at a lower elevation. Later in the storm life cycle, the CMA originates at a more northerly latitude than the WCB and in comparison is a relatively cold airstream. Airstream boundaries separating the WCB and the drystream are seen at almost all time periods. This feature acquires a forward-leaning orientation with time with only the lowermost boundaries being accompanied by a modest to strong temperature gradient. Two airstream boundaries involve the CMA. The first separates the CMA and the drystream and is a lower-tropospheric feature, particularly late in the storm life cycle. The second boundary is located north or northwest of the cyclone center and separates the CMA from northerly descending air. This midtropospheric feature occurs along a relatively weak temperature gradient. The fourth type of airstream boundary is referred to as a southwest confluence zone and separates northerly, descending airflow southwest of the cyclone center from easterly, rising airflow to the southeast. At the middle and later stages of the cyclone life cycle, this boundary is a lower-tropospheric feature. It is often associated with a relatively strong temperature gradient. The composites indicate that the evolution of the airstreams and airstream boundaries is remarkably similar for the three cyclone types, except that they are out of synchrony by one or more 12-h time steps. In particular, all three airstreams are evident on the precyclogenesis (time t 2 12) composite surfaces for the nondeveloping cyclones, whereas the full suite of airstreams does not appear until 12 h later for the developing cyclones.

A Climatology of Transition Season Colorado Cyclones: 1961–1990

Abstract Frequency, track, and intensity characteristics of transition season Colorado cyclones are investigated for the period 1961–90. Monthly cyclone totals are examined for evidence of seasonal frequency variations during the study period. Cyclone track maps for the months of April, May, October, and November are produced and analyzed for variations in azimuth and movement rates. In addition, the monthly distributions of minimum central pressure values are discussed. Transition season Colorado cyclone annual frequencies declined significantly during the period 1961–90, although the decline occurred primarily during the spring months. April has the most Colorado cyclone occurrences of the months examined. Spring and fall Colorado cyclone tracks are shown to be similar in trajectory and 48 h azimuth, though slightly variant in movement rates. Cyclones developing in months closer to the strong Northern Hemisphere winter circulation (April and November) regime tend to be more vigorous in terms of central ...

Research design and proposal writing in spatial science

Introduction • Rationale • Initial exposition of the “problem” • Context • Literature review • Case background • Research Question & Hypothesis • Methods • Data • Analysis • Interpretation • Results • Discussion • Conclusion • Summary • Implications for future research • In terms of the procedures associated with publishing an article, many excellent resources already exist. For this reason, only the general process is outlined: Identify potential journal outlets • Consider the audience • Review recent issues • Select a journal • Follow the exact style of the journal (i.e., citations, length, fi gures) • Consult previous issues & guidelines for authors • Once the manuscript has been submitted, the author should receive a letter verifying their submission is under review. After receiving this letter, the anxious author must wait 2–3 months or longer to learn of the editor’s decision. As a rule of thumb, authors should politely inquire as to the status of the review roughly 90 days after they receive the submission confi rmation notice from the editor. The editorial letter (or email) will usually include a cover letter that indicates the editor’s decision and highlights the reviewer comments. Additionally, the editor will provide the more in-depth assessments and comments of the reviewer. The editorial 66 7 Disseminating Resear ch decision itself may be somewhat confusing as few articles are accepted as submitted. Instead, editorial decisions are presented in the language below: Accept with minor revisions • Accept with revisions • The editor will clearly articulate the desired revisions in the cover letter • Revised & Resubmit (R&R) • The editor will highlight the concerns of the reviewers and request the author • to revise and resubmit. Most likely, the revised will undergo full or a modifi ed review process Inappropriate for the journal audience • Make revisions based on the reviews provided (as appropriate) and submit • elsewhere Not Suitable for Publication (Rejection) • Use the reviews to strengthen the manuscript and submit elsewhere • While every author awaits an acceptance letter, R&Rs, rejections, or suggestions for another outlet frequently occur. However, all authors—even the most recognized researchers in every fi eld—receive these letters and they should not be interpreted as a failure. Instead, use the peer review process to improve the article and re-submit elsewhere. In most cases, you—the author—will agree upon further refl ection with the assessment and decision. In those cases where the decision seems to be unwarranted though, it is often diffi cult to understand how or why the rejection occurs. However, protesting the decision of the editor is seldom a prudent or professional strategy to pursue. Instead, the author should use the review process to improve the article and move-on. Indeed, many major manuscripts from across all disciplines that would eventually be recognized as seminal works have been rejected at one time or another. The important thing is to approach the publishing process as a developmental one and to keep forging ahead as determination and hard work always wins the day. Based on our own experiences, rejected articles have been subsequently revised and later published in more appropriate and even more prestigious journals.

CLIMATOLOGY OF SURFACE CYCLONE TRAJECTORY AND INTENSITY FOR HEAVY-SNOW EVENTS AT THREE MIDWESTERN STATIONS

In this paper, we assess interstorm cyclone variations in intensity and motion for heavy-snow events at three north-central U.S. stations: Minneapolis, Madison, and Indianapolis. Daily data for the period from 1966 to 1996 were used to select the 157 storm events. Heavy-snow cyclone track location (latitude and longitude) and intensity (central pressure) means and standard deviations are calculated for each station and related to snowfall magnitude. The most northwesterly of the three stations, Minneapolis, had the largest median heavy-snowfall total and also the largest standard deviation in heavy-snowfall amount. Statistical analysis of surface cyclone parameters reveals significant interstation differences in storm trajectory and intensity measures for all cyclones and cyclogenesis group subsets. Chi-square tests suggest that the distribution of storms by month and cyclogenesis type is significantly nonrandom for all stations. Summary findings indicate that Midwestern heavy-snow events are dominated by southern Great Plains cyclones and that storms from secondary cyclogenic regions contribute to significant differences at the three selected locations. [Key words: cyclones, snowfall, Midwest.]

An Investigation of the Influence of Cyclonic Airstreams on Midwestern Snowfall

Although previous climatological studies have investigated the relationship between cyclone frequency and trajectory and regional weather, analyses of structural airflow features and precipitation have been confined to meteorological case studies. In the following paper, the influence of Colorado cyclone airstreams on Midwestern snowfall is investigated using isentropic streamline maps for five cold season months. Results indicate that Colorado cyclones account for a minor percentage of Midwestern snowfall events and amounts. When snowfall is induced by Colorado cyclogenesis, diffluence and instability in the cold sector portions of the cyclone are the dominant lifting mechanisms.

THE ROLE OF STRATOSPHERIC INTRUSIONS IN COLORADO CYCLOGENESIS

Isentropic composites and correlation analyses are employed to investigate the impact of stratospheric air intrusions during Colorado cyclogenesis. A sample of cold-season Colorado cyclones is partitioned into evolution categories (early, late, and non-developing systems) and examined for relationships between surface intensity measures and depression of the tropopause. Maps of isentropic potential vorticity for time periods prior to and up to 48 hours following cyclogenesis are utilized to determine the mean evolution of the stratospheric intrusion for each development type. Correlations are calculated to elucidate further the tropopause and surface variable associations suggested by the composites. Composite patterns and correlation results provide strong climatological evidence of a substantial contribution from stratospheric intrusion to surface development. Developing cyclones are characterized by progressive, intensifying depressions of the tropopause, while nondeveloping systems exhibit retreating ...

Grants and Grant Writing

One of the many reasons that people enter into academia is for the opportunity to work on their own research projects. Often working on individual research projects requires external funding, and obtaining external funding is not easy. In fact, it is one of the most challenging things that academics do. However, it is very rewarding when researchers are provided funds that enable them to perform research. This is especially true in times of tight institutional budgets or fiscal insecurity.