The dynamics of a high-speed Jovian jet     

Tony Maxworthy 《Planetary and Space Science》1984,32(8):1053-1058

We present new measurements of the velocity field in the neighborhood of the high-speed jet located at approx. 24° N latitude in the Jovian atmosphere. The maximum zonal velocity is found to be 182 ± 10 m s^?1 located at 23.7 ±0.2° N and representing the largest velocity measured on the planet. The distinctive cloud markings found close to this latitude are discussed and possible dynamical consequences presented.  相似文献   

Law of the sea: neglected issues     

Tony Loftas 《Marine Policy》1979,3(3):243-245

  相似文献   

Sources and sinks of nutrients in a New Zealand hill pasture catchment I. Stormflow generation     

James G. Cooke  Tony Dons 《水文研究》1988,2(2):109-122

The processes of stormflow generation were studied in a hill pasture catchment near Hamilton, New Zealand. Although rainfall was relatively evenly distributed throughout the year, stormflow was highly seasonal and over 65 per cent occurred during the winter. Three main processes contributing to stormflow were identified which could be related to soil type and physiographic position. On gleyed soils derived from rhyolitic colluvium, saturation overland flow was the dominant process. Hydrographs from ‘Whipkey’ throughflow troughs also indicated that there was a subsurface response (saturated wedge) from this soil type. On steeper convex slopes, more permeable soils were derived from weathered greywacke. The presence of ephemeral springs on the hillslopes and direct observation during storm events indicated that storm runoff was generated as return flow from this soil. It was noted that nitrate concentrations from subsurface sources were 5–10 times higher than surface runoff. This difference in concentration was utilized in a chemical mixing equation which partitioned stormflow sources. This was compared with the stormflow predicted from rain falling on to saturated areas. There was good agreement between the two models for winter-spring events with respect to the volumes of surface runoff predicted, however the saturated areas model underestimated total stormflow. The results of the study are briefly discussed in terms of the potential for water quality management.  相似文献   

Temporary labour migration and sustainable post-conflict return in Sierra Leone     

Roy Maconachie  Tony Binns  Paul Tengbe  Reynold Johnson 《GeoJournal》2006,67(3):223-240

Economic and social development indicators suggest that the small West African state of Sierra Leone is among the poorest countries in the world. Sierra Leone’s economy and quality of life deteriorated rapidly during a decade of political instability and civil war in the 1990s, when many people fled their homes and abandoned their livelihoods due to the rebel insurgency. This paper examines the post-war reconstruction scenario in Sierra Leone and presents recent evidence from two rural communities in the Eastern Province that were badly affected by the conflict. The paper considers the links between the farming and diamond mining sectors, which, despite severe dislocation during the conflict period, have proved to be remarkably resilient. It is argued that seasonal labour mobility associated with this dual economy has not only continued to be a key ingredient in sustaining livelihood portfolios, but is actually an essential pre-condition for the creation of an enabling environment for sustainable post-conflict return.

Tony BinnsEmail:

  相似文献   

The effects of spatial autoregressive dependencies on inference in ordinary least squares: a geometric approach   总被引：1，自引：1，他引：0  

Tony E. Smith  Ka Lok Lee 《Journal of Geographical Systems》2012,14(1):91-124

There is a common belief that the presence of residual spatial autocorrelation in ordinary least squares (OLS) regression leads to inflated significance levels in beta coefficients and, in particular, inflated levels relative to the more efficient spatial error model (SEM). However, our simulations show that this is not always the case. Hence, the purpose of this paper is to examine this question from a geometric viewpoint. The key idea is to characterize the OLS test statistic in terms of angle cosines and examine the geometric implications of this characterization. Our first result is to show that if the explanatory variables in the regression exhibit no spatial autocorrelation, then the distribution of test statistics for individual beta coefficients in OLS is independent of any spatial autocorrelation in the error term. Hence, inferences about betas exhibit all the optimality properties of the classic uncorrelated error case. However, a second more important series of results show that if spatial autocorrelation is present in both the dependent and explanatory variables, then the conventional wisdom is correct. In particular, even when an explanatory variable is statistically independent of the dependent variable, such joint spatial dependencies tend to produce “spurious correlation” that results in over-rejection of the null hypothesis. The underlying geometric nature of this problem is clarified by illustrative examples. The paper concludes with a brief discussion of some possible remedies for this problem.  相似文献   

Validating a rapid-update satellite precipitation analysis across telescoping space and time scales     

Francis Joseph Turk  Byung-Ju Sohn  Hyun-Jong Oh  Elizabeth E. Ebert  Vincenzo Levizzani  Eric A. Smith 《Meteorology and Atmospheric Physics》2009,105(1-2):99-108

In order to properly utilize remotely sensed precipitation estimates in hydrometeorological applications, knowledge of the accuracy of the estimates are needed. However, relatively few ground validation networks operate with the necessary spatial density and time-resolution required for validation of high-resolution precipitation products (HRPP) generated at fine space and time scales (e.g., hourly accumulations produced on a 0.25° spatial scale). In this article, we examine over-land validation statistics for an operationally designed, meteorological satellite-based global rainfall analysis that blends intermittent passive microwave-derived rainfall estimates aboard a variety of low Earth-orbiting satellite platforms with sub-hourly time sampling capabilities of visible and infrared imagers aboard operational geostationary platforms. The validation dataset is comprised of raingauge data collected from the dense, nearly homogeneous, 1-min reporting Automated Weather Station (network of the Korean Meteorological Administration during the June to August 2000 summer monsoon season. The space-time RMS error, mean bias, and correlation matrices were computed using various time windows for the gauge averaging, centered about the satellite observation time. For ±10 min time window, a correlation of 0.6 was achieved at 0.1° spatial scale by averaging more than 3 days; coarsening the spatial scale to 1.8° produced the same correlation by averaging over 1 h. Finer than approximately 24-h and 1° time and space scales, respectively, a rapid decay of the error statistics was obtained by trading-off either spatial or time resolution. Beyond a daily time scale, the blended estimates were nearly unbiased and with an RMS error of no worse than 1 mm day^?1.  相似文献   

Ternary forecast of heavy snowfall in the Honam area,Korea     

Keon Tae SOHN  Jeong Hyeong LEE  Young Seuk CHO 《大气科学进展》2009,26(2):327-332

The objective of this study is to improve the statistical modeling for the ternary forecast of heavy snowfall in the Honam area in Korea. The ternary forecast of heavy snowfall consists of one of three values, 0 for less than 50 mm, 1 for an advisory (50–150 mm), and 2 for a warning (more than 150 mm). For our study, the observed daily snow amounts and the numerical model outputs for 45 synoptic factors at 17 stations in the Honam area during 5 years (2001 to 2005) are used as observations and potential pre...  相似文献   

Old stellar population synthesis： new age and mass estimates for Mayall Ⅱ = G1     

Jun Ma  ;Richard de Grijs  ;Zhou Fan  ;Soo-Chang Rey  ;Zhen-Yu Wu  ;Xu Zhou  ;Jiang-Hua Wu  ;Zhao-Ji Jiang  ;Jian-Sheng Chen  ;Kyungsook Lee  ;Sangmo Tony Sohn 《天体物理学报》2009,(6):641-652

Mayall Ⅱ = G1 is one of the most luminous globular clusters （GCs） in M31. Here, we determine its age and mass by comparing multicolor photometry with theoretical stellar population synthesis models. Based on far- and near-ultraviolet GALEX photometry, broad-band UBVRI, and infrared JHKs 2MASS data, we construct the most extensive spectral energy distribution of G 1 to date, spanning the wavelength range from 1538 to 20 000A. A quantitative comparison with a variety of simple stellar population （SSP） models yields a mean age which is consistent with G1 being among the oldest building blocks of M31 and having formed within ～1.7 Gyr after the Big Bang. Irrespective of the SSP model or stellar initial mass function adopted, the resulting mass estimates （of order 10^7M⊙） indicate that GI is one of the most massive GCs in the Local Group. However, we speculate that the cluster＇s exceptionally high mass suggests that it may not be a genuine GC. Our results also suggest that G1 may contain, on average, （1.65±0.63） × 10^2L⊙ far-ultraviolet-bright, hot, extreme horizontal-branch stars, depending on the adopted SSP model. In addition, we demonstrate that extensive multi-passband photometry coupled with SSP analysis enables one to obtain age estimates for old SSPs that have similar accuracies as those from integrated spectroscopy or resolved stellar photometry, provided that some of the free parameters can be constrained independently.  相似文献   

Relational Agriculture: Gender,Sexuality, and Sustainability in U.S. Farming     

Isaac Sohn Leslie  Jaclyn Wypler  Michael Mayerfeld Bell 《社会与自然资源》2019,32(8):853-874

Although 97% of U.S. farms are “family-owned,” little research examines how gender and sexual relationships – inherent in familial dynamics – influence farmers’ practices and livelihoods. Gender and sexual dynamics – shaped by race and class – affect who is considered a farmer, land management decisions, and access to resources like land, subsidies, and knowledge. We use feminist and queer lenses to illuminate how today’s agricultural gender and sexual relations are not “natural,” but when left uninterrogated are constructed in ways that harm women and queer farmers while limiting potential to develop sustainable practices. Women and queer farmers also resist, “re-orienting” gender and sexual relations in ways that expand possibilities for achieving food justice and ecological sustainability. We offer “relational agriculture” as a tool for making visible and re-orienting gender and sexual relations on farms. Relational agriculture brings sexuality into food justice and demonstrates the centrality of gender and sexuality to agricultural sustainability.  相似文献   

Bleaching of the post‐IR IRSL signal: new insights for feldspar luminescence dating     

Romée H. Kars  Tony Reimann  Christina Ankjærgaard  Jakob Wallinga 《Boreas: An International Journal of Quaternary Research》2014,43(4):780-791

Post‐infrared (pIR) stimulated luminescence dating of sedimentary feldspar largely avoids the effects of anomalous fading that affect conventional infrared stimulated luminescence (IRSL) dating. However, optical resetting of pIR signals is more difficult than resetting the conventional IRSL signal, which may undermine the crucial assumption that pIR signals were effectively bleached upon deposition and burial of sediment grains. In this study, we quantify the bleaching properties of several pIR signals on various samples using laboratory‐simulated bleaching in full sunlight and water‐attenuated sunlight. Our data show that bleaching is most efficient under full spectrum conditions for all pIR signals and that pIR signals measured at elevated temperature are increasingly harder to bleach than IR and pIR signals measured at low temperature (e.g. IR at 50°C). All bleaching curves exhibit a very slow and steady decrease, indicating that a fixed un‐bleachable residual level cannot be reached within the 11 days of solar simulator exposure undertaken here. We show that the magnitude of a laboratory‐determined residual dose depends on the adopted bleaching protocol and cannot be used as a proxy for the dose that remains in the sample at the time of burial (remnant dose). Our data emphasize the importance of finding a balance between sufficient signal stability and a minimized contribution of a remnant dose when using pIR procedures for feldspar luminescence dating.  相似文献