User Guides & Manuscripts

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Confidence intervals for forecast verification: Practical considerations
Confidence intervals for forecast verification: Practical considerations
This manuscript is intended to give a simple overview to constructing and using confidence intervals for the purposes of forecast verification. A more detailed manuscript on the subject can be found in Gilleland (2010).
Coronal "dark energy" and solar/stellar activity
Coronal "dark energy" and solar/stellar activity
Magnetic fields in stellar atmospheres are believed to play the major role in stellar activity such as flares and atmospheric heating. However, the spatial scales on which conversion of magnetic energy to other forms takes place are small and cannot be resolved in stellar observations. Solar observations of the magnetic fields in the atmosphere and the physical processes that lead to energy release remain our best prospect for advancing our understanding of stellar activity. This white paper summarizes the current state of observations of magnetic fields in the solar atmosphere, describes prospects for much improved measurements with new instruments, and discusses the connections to stellar science.
Extremes toolkit (extRemes): Weather and climate applications of extreme value statistics
Extremes toolkit (extRemes): Weather and climate applications of extreme value statistics
The Extremes Toolkit (extRemes) is designed to facilitate the use of extreme value theory in applications oriented toward weather and climate problems that involve extremes, such as the highest temperature over a fixed time period. This effort is motivated by the continued use of traditional statistical distributions (normal, lognormal, gamma, ...) in situations where extreme value theory is applicable. The goal is to write a GUI prototype to interact with a high-level language capable of advanced statistical applications. Computational speed is secondary to development time. With these guidelines, the language R [14] was chosen in conjunction with a Tcl/Tk interface. R is a GNU-license product available at www.r-project.org. Tcl/Tk is a popular GUI development platform also freely available for Linux, Unix and the PC (see section 8.0.22 for more details). While the software can be used without the graphical interface, beginning users of R will probably want to start by using the GUI. If its limitations begin to inhibit, it may be worth the investment to learn the R language. The majority of the code was adapted by Alec Stephenson from routines by Stuart Coles. Coles’ book [3] is a useful text for further study of the statistical modeling of extreme values. This toolkit and tutorial do not currently provide for fitting models for multivariate extremes or spatiotemporal extremes. Such functionality may be added in the future, but no plans currently exist and only univariate methods are provided.
Predicted impacts of climate change on ground level ozone in cities in the Western United States
Predicted impacts of climate change on ground level ozone in cities in the Western United States
Ground-level ozone is a major pollutant throughout the world that causes many of the human health problems associated with air pollution. This project seeks to discover the impact of climate change on ground-level ozone in six cities in the Western United States. This was done by determining how many days per summer have ozone levels above the EPA standard (75 ppb) in the present climate and then estimating changes if the projected temperature values were to rise two or four degrees Fahrenheit. Models expect these temperature increases to occur near 2030 and 2050, respectively. The more stringent Canadian standard (65 ppb) was also used because studies show that ozone levels lower than the EPA standard are still detrimental to human health. The results showed an overall trend of increasing summer days with above-standard ozone: on average, the number of days above the American standard increased by 2.3 by 2030 and 5.0 by 2050 in these six cities. Average increases of 3.0 days by 2030 and 6.0 by 2050 were predicted using the Canadian standard. Significantly more days were expected to exceed the Canadian standard than the American standard. This study shows that all of the studied cities have summertime ozone levels that pose risk to human health and suggests that these problems will increase in the future with rising temperatures. This manuscript was prepared as part of the pre-college internship program, which was run by NCAR/RAL and Spark during the summer, 2012.
Primer on economics for national meteorological and hydrological services
Primer on economics for national meteorological and hydrological services
This primer on economic theory, methods, and applications is primarily for members of the weather community. It is intended to increase their understanding of economic methods and their applicability in evaluating both the impacts of national meteorological and hydrological services (NMHS) and the associated benefits and costs of those services. To this end, the document (1) explains the concept and practice of an economic benefit-cost analysis (BCA); (2) discusses why conducting such economic analyses is important and useful; (3) offers guidance on how to conduct BCAs and document and communicate the inputs and outputs of such analyses; and (4) presents illustrations of economic analysis for NMHS projects in the form of case studies.
Spatial forecast verification: Thin plate splines
Spatial forecast verification: Thin plate splines
The present paper introduces the thin-plate spline as a potentially useful tool for spatial forecast verification. The approach can be used as both a neighborhood type (i.e., low-pass filter) method as well as a scale decomposition approach. In particular, a thin-plate spline can be represented in a symbolically equivalent manner as a wavelet decomposition. Briggs and Levine (1997) suggest the use of wavelets for forecast verification because of their ability to not only break a field down by physical scales, but also because the locations of the features at each scale are also preserved. For example, if one played a chord on a piano and applied Fourier analysis to decompose the chord, each individual note of the chord could be identified. However, if a second chord were played, again all of the notes can be identified, but no information is available as to which chords the notes belong. Wavelets, on the other hand, allow one to identify the individual notes, and to which chords they correspond (Ogden 1996; Meyer 1993).

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