DROUGHT AND CLIMATE CHANGE: IMPLICATIONS FOR THE WEST

Environmental Economics and Policy,

Effects of Climate Change on Water Resources

Environmental Economics and Policy, Resource /Energy Economics and Policy, Q25, Q54,

The persistence of drought impacts across growing seasons: a dynamic stochastic analysis

Agricultural producers throughout much of the United States experienced one of the most severe droughts in the last 100 years during the years 1999-2006. The prolonged nature of this drought highlights a need to better understand the impacts and management of drought across growing seasons, rather than just within a growing season. Producers express specific concern about the tendency of drought impacts to persist even after drought itself has subsided. The persistence of drought impacts has received limited attention in the economics literature. The objectives of this study are two-fold: 1) to determine whether inter-year dynamics, in the form of agronomic constraints and financial flows, can cause persistence of a drought's impact in years subsequent to the drought, and 2) to determine whether the impact of one year of drought can alter the impact of a subsequent year of drought. A multi-year, dynamic and stochastic decision model is developed in a discrete stochastic programming framework and solved to address the objectives. The structure and parameters of the farm-level model are based on irrigated row crop farms in eastern Oregon, USA. Analysis of the model's solution reveals the following results: 1) the impact of a drought can persist long after the drought subsides, and 2) the impact of one year of drought can alter the impact of a subsequent year of drought. Potential implications for the administration of drought-related assistance are discussed briefly.Drought, preparedness, response, uncertainty, dynamics, discrete stochastic programming, agriculture, irrigation, eastern Oregon, row crops, crop rotation, Crop Production/Industries, Risk and Uncertainty,

Variation in size of living articulated brachiopods with latitude and depth

Geographical variations in animal characters are one of the main subjects for study in macroecology. Variation with latitude has received special interest. Articulated brachiopods are possibly the commonest macrofossil with large variations in size of taxa through the fossil record. Here, we investigate trends in size of the 3 main orders of articulated brachiopod with latitude and depth. Data were insufficient to identify patterns in Thecideida (a micromorph taxon only recorded from low latitudes). Rhynchonellida had no clear trends in size with latitude or depth. Terebratulida exhibited hemispheric differences in size relations, with increasing length of species towards the pole in the south and no significant trend in the north. Tropical species were small (<20 mm length between 10°N and 10°S), and the largest species were found between 30° and 60° latitude in both hemispheres. There were no articulated brachiopods recorded from the high arctic, and support for a continuous trend in size with latitude was small or absent. In Terebratulida, there was a significant decrease in species length with depth of 1.7 mm per 100 m depth increase. These trends could be explained by competition for space and reduced availability of habitat with progressive depth beyond the continental shelf

Frequency-dependent polarizabilities of alkali atoms from ultraviolet through infrared spectral regions

We present results of first-principles calculations of the frequency-dependent polarizabilities of all alkali atoms for light in the wavelength range 300-1600 nm, with particular attention to wavelengths of common infrared lasers. We parameterize our results so that they can be extended accurately to arbitrary wavelengths above 800 nm. This work is motivated by recent experiments involving simultaneous optical trapping of two different alkali species. Our data can be used to predict the oscillation frequencies of optically-trapped atoms, and particularly the ratios of frequencies of different species held in the same trap. We identify wavelengths at which two different alkali atoms have the same oscillation frequency.Comment: 6 pages, 2 figure

OPPORTUNITY COSTS OF WATER LEASING: IRRIGATION, INSTREAM FLOW, AND WETLAND CONSIDERATIONS IN THE LARAMIE BASIN, WYOMING

Flood irrigation in the Laramie Basin of southeast Wyoming has created many wetlands that rely directly on irrigation inputs for water. The Laramie Basin is a proposed water source for enhancing Platte River instream flows, to the benefit of endangered cranes, terns, plovers, and sturgeons. Increasing irrigation efficiency, or retiring irrigated lands would transform Laramie Basin agriculture and cause a high fraction of the Basins wetlands to be lost. This study explores the limitations of traditional water transfer tools when regional instream-flow requirements compete for water with local irrigation-dependent wetlands. A rotating short-term water lease program is proposed. The program would allow Laramie Basin producers to contribute to instream flow without causing permanent wetland damage or loss. Short-term water leasing programs could allow agricultural communities to contribute to regional environmental water needs without sacrificing local, agriculturally-based ecological resources. An estimate of minimum water costs, advantages and disadvantages of short-term water leasing are discussed.Resource /Energy Economics and Policy,

The joint US/UK 1990 epoch world magnetic model

A detailed summary of the data used, analyses performed, modeling techniques employed, and results obtained in the course of the 1990 Epoch World Magnetic Modeling effort are given. Also, use and limitations of the GEOMAG algorithm are presented. Charts and tables related to the 1990 World Magnetic Model (WMM-90) for the Earth's main field and secular variation in Mercator and polar stereographic projections are presented along with useful tables of several magnetic field components and their secular variation on a 5-degree worldwide grid

Latitudinal and depth gradients in marine predation pressure

There is a general paradigm that marine predation pressure increases towards the tropics and decreases with depth. However, data demonstrating global trends are generally lacking. Rhynchonelliform brachiopods inhabit all the oceans and often survive shell-crushing predator attacks. We investigate shell repair in brachiopods across a range of Southern Hemisphere and tropical Northern Hemisphere latitudes and depths

Obscuration of the Parsec Scale Jets in the Compact Symmetric Object 1946+708

We present results of VLA and VLBA observations of the 1.420 GHz neutral hydrogen absorption associated with the Compact Symmetric Object 1946+708 (z=0.101). We find significant structure in the gas on parsec scales. The peak column density in the HI (N_HI~2.2x10^23 cm^-2 (T_s/8000K)) occurs toward the center of activity of the source, as does the highest velocity dispersion (FWHM~350 \kms). In addition, we find that the continuum spectra of the various radio components associated with these jets strongly indicate free-free absorption. This effect is particularly pronounced toward the core and inner components of the receding jet, suggesting the presence of a screen local to the source, perhaps part of an obscuring torus.Comment: revised version, some text added, 1 figure changed; accepted to Astrophysical Journal, 22 page LaTeX document includes 8 postscript figure

No ocean acidification effects on shell growth and repair in the New Zealand brachiopod Calloria inconspicua (Sowerby, 1846)

Surface seawaters are becoming more acidic due to the absorption of rising anthropogenic CO2. Marine calcifiers are considered to be the most vulnerable organisms to ocean acidification due to the reduction in the availability of carbonate ions for shell or skeletal production. Rhychonelliform brachiopods are potentially one of the most calcium carbonate-dependent groups of marine organisms because of their large skeletal content. Little is known, however, about the effects of lowered pH on these taxa. A CO2 perturbation experiment was performed on the New Zealand terebratulide brachiopod Calloria inconspicua to investigate the effects of pH conditions predicted for 2050 and 2100 on the growth rate and ability to repair shell. Three treatments were used: an ambient pH control (pH 8.16), a mid-century scenario (pH 7.79), and an end-century scenario (pH 7.62). The ability to repair shell was not affected by acidified conditions with >80% of all damaged individuals at the start of the experiment completing shell repair after 12 weeks. Growth rates in undamaged individuals >3 mm in length were also not affected by lowered pH conditions, whereas undamaged individuals <3 mm grew faster at pH 7.62 than the control. The capability of C. inconspicua to continue shell production and repair under acidified conditions suggests that this species has a robust control over the calcification process, where suitable conditions at the site of calcification can be generated across a range of pH conditions