Snow disappearance timing is dominated by forest effects on snow accumulation in warm winter climates of the Pacific Northwest,United States

Forests modify snow processes and affect snow water storage as well as snow disappearance timing. However, forest influences on snow accumulation and ablation vary with climate and topography and are therefore subject to temporal and spatial variability. We utilize multiple years of snow observations from across the Pacific Northwest, United States, to assess forest–snow interactions in the relatively warm winter conditions characteristic of maritime and transitional maritime–continental climates. We (a) quantify the difference in snow magnitude and disappearance timing between forests and open areas and (b) assess how forest modifications of snow accumulation and ablation combine to determine whether snow disappears later in the forest or in the open. We find that snow disappearance timing at 12 (out of 14) sites ranges from synchronous in the forest and open to snow persisting up to 13 weeks longer in the open relative to a forested area. By analyzing accumulation and ablation rates up to the day when snow first disappears from the forest, we find that the difference between accumulation rates in the open and forest is larger than the difference between ablation rates. Thus, canopy snow interception and subsequent loss, rather than ablation, set up longer snow duration in the open. However, at two relatively windy sites (hourly average wind speeds up to 8 and 17 m/s), differential snow disappearance timing is reversed: Snow persists 2–5 weeks longer in the forest. At the windiest sites, accumulation rates in the forest and open are similar. Ablation rates are higher in the open, but the difference between ablation rates in the forest and open at these sites is approximately equivalent to the difference at less windy sites. Thus, longer snow retention in the forest at the windiest sites is controlled by depositional differences rather than by reduced ablation rates. These findings suggest that improved quantification of forest effects on snow accumulation processes is needed to accurately predict the effect of forest management or natural disturbance on snow water resources.     

Ground truthed performance of single‐and dual‐polarized radar rain rates at large ranges

Radar accuracy in estimating qualitative precipitation estimation at distances larger than 120 km degrades rapidly because of increased volume coverage and beam height. The performance of the recently upgraded dual‐polarized technology to the NEXRAD network and its capabilities are in need of further examination, as improved rainfall estimates at large distances would allow for significant hydrological modelling improvements. Parameter based methods were applied to radars from St. Louis (KLSX) and Kansas City (KEAX), Missouri, USA, to test the precision and accuracy of both dual‐ and single‐polarized parameter estimations of precipitation at large distances. Hourly aggregated precipitation data from terrestrial‐based tipping buckets provided ground‐truthed reference data. For all KLSX data tested, an R(Z,ZDR) algorithm provided the smallest absolute error (3.7 mm h^?1) and root‐mean‐square‐error (45%) values. For most KEAX data, R(ZDR,KDP) and R(KDP) algorithms performed best, with RMSE values of 37%. With approximately 100 h of precipitation data between April and October of 2014, nearly 800 and 400 mm of precipitation were estimated by radar precipitation algorithms but was not observed by terrestrial‐based precipitation gauges for KLSX and KEAX, respectively. Additionally, nearly 30 and 190 mm of measured precipitation observed by gauges were not detected by the radar rainfall estimates from KLSX and KEAX, respectively. Results improve understanding of radar based precipitation estimates from long ranges thereby advancing applications for hydrometeorological modelling and flood forecasting. Copyright © 2016 John Wiley & Sons, Ltd.     

Why there is no Detroit in Canada

Despite significant structural similarities, Canadian and American Rust Belt cities have very different levels of inner core land abandonment. Cities like Detroit and Cleveland are filled with thousands of vacant lots. No abandonment of this magnitude exists in the Canadian Rust Belt, despite significant deindustrialization, suburbanization, wealth, and localist politics—all factors theorized to be central causes for American Rust Belt abandonment. This paper considers why such a vast difference in land abandonment exists between the two contexts. It centers on the role of racialization, but in a way that challenges Canadian exceptionalist narratives about the ostensible lack of racialization. Racialization took place on both sides of the border, I argue, but only the American form contributed to land abandonment.     

Satellite All-sky Infrared Radiance Assimilation: Recent Progress and Future Perspectives

Satellite infrared(IR)sounder and imager measurements have become one of the main sources of data used by data assimilation systems to generate initial conditions for numerical weather prediction(NWP)models and atmospheric analysis/reanalysis.This paper reviews the development of satellite IR data assimilation in NWP in recent years,especially the assimilation of all-sky satellite IR observations.The major challenges and future directions are outlined and discussed.     

Injection experiments and thermal recovery in corehole OH-1, Lake City,California

Two injection tests, shallow and deep, followed by repeated temperature logging were performed in the Lake City, California OH-1 corehole, to delineate permeable zones, investigate the permeability of rocks adjacent to the wellbore, and to test the validity of maximum-reading thermometer (MRT) measurements collected during the drilling process that show lower than static temperatures above a depth of 2100 ft and significantly higher than static temperatures below a depth of about 2500 ft. The tests confirmed several permeable zones in OH-1. At about 300 ft, there is a strong zone of lateral flow, and at 947 ft there is a major outflow zone for injected fluid. Two other possible permeable flow zones were detected from the thermal recovery logs: one at about 1500 ft and another at about 2300 ft. The 2300 ft permeable zone seems to be an inflow zone, and the source of a probable downflow responsible for cooling the wellbore below about 2500 ft. The hotter MRT data obtained during drilling may be reconciled with the significantly lower static temperature logs if downflow from about 2300 ft is present.     

Reef parameterisation schemes with applications to tidal modelling

A variety of analytical models is used to investigate the effects on tidal propagation of a barrier reef system. These models specify reef geometry by two parameters. They can accommodate cases where water flows over reefs, as well as through inter-reef gaps, and also incorporate quadratic bottom friction. Although based on a one-dimensional approach, adaptations of a solution by Huthnance are used to account for the additional blockage effects associated with two-dimensional flow patterns near reef barriers. The present work adopts the philosophy that only a numerical approach can cope with the wide variations in reef geometry that are encountered in areas such as the Great Barrier Reef (GBR) region of Australia. Moreover, since typical model grids cannot resolve inter-reef gaps and other features with sufficient accuracy, a parameterised approach is needed to accommodate the conflicting demands of reef geometry and an economically feasible model resolution. The formulation of the analytical models is such that they can be applied immediately to standard numerical algorithms. Numerical experiments for flow in a channel, with a reef barrier across its centre, are used to test the parameterisation schemes. Comparison of the results for parameterised reefs with those obtained using extremely fine grids, shows convincing evidence of the success of the schemes. A separate method for automatically generating reef parameters has simplified the task of applying the methodology to real reefal systems. A tidal model of the Southern GBR, a region which exhibits unusual tidal behaviour, but which also has ample field data available for model testing, is used to demonstrate the accuracy that can be attained with the parameterised approach. Although tides are considered specifically in the present work, the formulation should be applicable with equal ease to the many other significant classes of low frequency motions in the GBR.     

An evaluation of sampling and full enumeration strategies for Fisher Jenks classification in big data settings

Large data contexts present a number of challenges to optimal choropleth map classifiers. Application of optimal classifiers to a sample of the attribute space is one proposed solution. The properties of alternative sampling‐based classification methods are examined through a series of Monte Carlo simulations. The impacts of spatial autocorrelation, number of desired classes, and form of sampling are shown to have significant impacts on the accuracy of map classifications. Tradeoffs between improved speed of the sampling approaches and loss of accuracy are also considered. The results suggest the possibility of guiding the choice of classification scheme as a function of the properties of large data sets.     

Ecophysiological responses to elevated CO<Subscript>2</Subscript> and temperature in <Emphasis Type="Italic">Cystoseira tamariscifolia</Emphasis> (Phaeophyceae)

Ocean acidification increases the amount of dissolved inorganic carbon (DIC) available in seawater which can benefit photosynthesis in those algae that are currently carbon limited, leading to shifts in the structure and function of seaweed communities. Recent studies have shown that ocean acidification-driven shifts in seaweed community dominance will depend on interactions with other factors such as light and nutrients. The study of interactive effects of ocean acidification and warming can help elucidate the likely effects of climate change on marine primary producers. In this study, we investigated the ecophysiological responses of Cystoseira tamariscifolia (Hudson) Papenfuss. This large brown macroalga plays an important structural role in coastal Mediterranean communities. Algae were collected from both oligotrophic and ultraoligotrophic waters in southern Spain. They were then incubated in tanks at ambient (ca. 400–500 ppm) and high CO₂ (ca. 1200–1300 ppm), and at 20 °C (ambient temperature) and 24 °C (ambient temperature +4 °C). Increased CO₂ levels benefited the algae from both origins. Biomass increased in elevated CO₂ treatments and was similar in algae from both origins. The maximal electron transport rate (ETR_max), used to estimate photosynthetic capacity, increased in ambient temperature/high CO₂ treatments. The highest polyphenol content and antioxidant activity were observed in ambient temperature/high CO₂ conditions in algae from both origins; phenol content was higher in algae from ultraoligotrophic waters (1.5–3.0%) than that from oligotrophic waters (1.0–2.2%). Our study shows that ongoing ocean acidification can be expected to increase algal productivity (ETR_max), boost antioxidant activity (EC ₅₀ ), and increase production of photoprotective phenols. Cystoseira tamariscifolia collected from oligotrophic and ultraoligotrophic waters were able to benefit from increases in DIC at ambient temperatures. Warming, not acidification, may be the key stressor for this habitat as CO₂ levels continue to rise.