Using Synthetic Aperture Radar to Define Spring Breakup on the Kuparuk River, Northern Alaska

Spring runoff measurements of Arctic watersheds are challenging given the remote location and the often dangerous field conditions. This study combines remote sensing techniques and field measurements to evaluate the applicability of synthetic aperture radar (SAR) to defining spring breakup of the braided lower Kuparuk River, North Slope, Alaska. A statistical analysis was carried out on a time series (2001–10) of SAR images acquired from the European Remote-Sensing Satellite (ERS-2) and the Canadian RADARSAT satellite, as well as on measured runoff. On the basis of field information, the SAR images were separated into pre-breakup, breakup, and post-breakup periods. Three variables were analyzed for their suitability to bracket the river breakup period: image brightness, variance in brightness over the river length, and a sum of rank order change analysis. Variance in brightness was found to be the most reliable indicator. A combined use of that variance and sum of rank order change appeared promising when enough images were available. The temporal resolution of imagery served as the major limitation in constraining the timing of the hydrologic event. Challenges associated with spring runoff monitoring and the sensitive nature of SAR likely resulted in an earlier detection of surficial changes by the remote sensing technique compared to the field runoff observations. Given a sufficient temporal resolution, SAR imagery has the potential to improve the spatiotemporal monitoring of Arctic watersheds for river breakup investigations.La mesure de l’écoulement printanier des bassins hydrographiques de l’Arctique n’est pas facile à réaliser en raison de l’éloignement ainsi qu’en raison des conditions souvent dangereuses qui ont cours sur le terrain. Cette étude fait appel à des techniques de télédétection de même qu’aux mesures prises sur le terrain pour évaluer l’applicabilité du radar à synthèse d’ouverture SAR pour définir la débâcle printanière de la basse rivière Kuparuk anastomosée sur la North Slope de l’Alaska. L’analyse statistique d’une série temporelle (2001-2010) d’images SAR acquises à partir du satellite européen de télédétection (ERS-2) et du satellite canadien RADARSAT ainsi que des écoulements mesurés a été effectuée dans le cadre de cette étude. D’après les renseignements recueillis sur le terrain, les images SAR ont été divisées en fonction de la période précédant la débâcle, de la période de la débâcle même et de la période suivant la débâcle. Trois variables ont été analysées afin de déterminer si elles permettaient d’isoler la période de la débâcle de la rivière, soit la luminance de l’image, la variance de la luminance en fonction de la longueur de la rivière et la somme de l’analyse des changements de classement suivant le rang. La variance de la luminance s’est avérée l’indicateur le plus fiable. L’utilisation conjointe de cette variance et de la somme des changements de classement suivant le rang s’avéraient prometteuse lorsque le nombre d’images était suffisant. La résolution temporelle de l’imagerie a constitué la plus grande limitation pour contraindre la temporisation de l’événement hydrologique. Les défis liés à la surveillance de l’écoulement printanier et la nature sensible du SAR ont vraisemblablement donné lieu à la détection précoce des changements superficiels au moyen de la technique de télédétection comparativement aux observations mêmes de l’écoulement printanier. Moyennant une résolution temporelle suffisante, l’imagerie SAR pourrait permettre d’améliorer la surveillance spatiotemporelle des bassins hydrographiques de l’Arctique en vue de l’étude des débâcles printaniers

Stillbirth and loss: family practices and display

This paper explores how parents respond to their memories of their stillborn child over the years following their loss. When people die after living for several years or more, their family and friends have the residual traces of a life lived as a basis for an identity that may be remembered over a sustained period of time. For the parent of a stillborn child there is no such basis and the claim for a continuing social identity for their son or daughter is precarious. Drawing on interviews with the parents of 22 stillborn children, this paper explores the identity work performed by parents concerned to create a lasting and meaningful identity for their child and to include him or her in their families after death. The paper draws on Finch's (2007) concept of family display and Walter's (1999) thesis that links continue to exist between the living and the dead over a continued period. The paper argues that evidence from the experience of stillbirth suggests that there is scope for development for both theoretical frameworks

Ohio Northern Alumnus - July, 1927

https://digitalcommons.onu.edu/alumni_mag/1001/thumbnail.jp

Studies of Fusarium associated with containerized conifer seedling diseases : pathogenicity tests of isolates from the Alpine Nursery, Kalispell, Montana

Isolates of Fusarium oxysporum, F. acuminatum, and F. sambucinum obtained from peat-vermiculite soil mixes were tested for pathogenicity on ponderosa pine, lodgepole pine, western larch, and blue spruce containerized seedlings and on germination of Scots pine and blue spruce seed. Ponderosa pine seedling were the least susceptible to killing by the Fusarium isolates tested. Fusarium acuminatum was the most pathogenic and F. sambucinum the least pathogenic on seedlings. Isolates of F. oxysporum ranged in virulence from very low to moderately high. The only isolate that consistently reduced seed germination was F. acuminatum. Time required for germination was generally not affected by the Fusarium isolate tested. Seedling inoculation techniques allowed for successful differentiation of the pathogenic potential of the Fusarium isolates tested

Containerized Engelmann spruce seedling diseases at the USDA Forest Service Nursery, Coeur d'Alene, Idaho

An evaluation was conducted at the USDA Forest Service Nursery, Coeur d'Alene, Idaho, to quantify the occurrence of diseases in the spring 1984 crop of containerized Engelmann spruce seedlings. The crop included 19 separate seedlots from seven National Forests in the Northern Region. An overall production rate of 94.5 percent was achieved for the crop (5.5 percent of the crop was lost to diseases or other mortality factors). Dead or diseased seedlings accounted for only 0.7 percent of the total losses, whereas empty cells accounted for the remaining 4.8 percent. Major disease organisms included Sirococcus strobilinus, Fusarium oxysporum, F. avenaceum, F. solani, F. tricinctum, Cylindrocarpon tenue, Phoma herbarum, P. fimeti, and Botrytis cinerep. Sirococcus caused disease in 18 of the 19 seedlots and was usually encountered about 11 weeks after sowing. Fusarium diseases occurred with greatest frequency shortly after germinate emergence

Occurrence of Fusarium on leach pine cells from the USDA Forest Service Nursery, Coeur d'Alene, Idaho

Three hundred fifty Leach pine cells used to grow containerized conifer seedlings at the USDA Forest Service Nursery in Coeur d'Alene, Idaho, were sampled for Fusarium and Trichoderma colonization. Cells were either sampled prior to or after cleaning. Cleaning reduced Fusarium colonization from 86 percent of the cells to about 50 percent. Cells stored for several months still contained high levels of Fusarium inoculum. Most Fusarium inoculum was concentrated at or near the bottom of cells. Cells with high Fusarium levels had corresponding low levels of Trichoderma and vice versa. Ability of the Fusarium isolates from cells to cause seedling diseases is unknown, but Fusarium-caused disease is common at the nursery

Evaluation of root diseases of containerized conifer seedlings at the Champion Timberlands Nursery, Plains, Montana

Investigations of containerized conifer seedling root diseases at the Champion Timberlands Nursery revealed that Fusarium oxysporum was most commonly isolated from seed, seedling roots, and styroblock containers. Amount of seed infection varied widely among the seedlots tested, but was usually below 5 percent. Runningwater rinses did not reduce amounts of Fusarium detected on seed. Douglas-fir and lodgepole pine seedlings with disease symptoms had roots that were much more colonized with Fusarium than seedlings without symptoms. Fusarium inoculum existed within soil mixes and on root fragments within seedling plugs. The inner walls of styroblocks were also extensively colonized with Fusarium, especially at the bottom of the plug. Hot water cleaning and treatment with bleach reduced, but did not eliminate, Fusarium within styroblocks. Sufficient inoculum remained to pose potential threats to subsequent crops of seedlings. Resistance to benomyl was not detected with in vitro tests, although most F. oxysporum isolates displayed some level of resistance to captan, Botran, and Banrot