Monitoring Snow Using Geostationary Satellite Retrievals During the SAAWSO Project     

Robert M. Rabin  Ismail Gultepe  Robert J. Kuligowski  Andrew K. Heidinger 《Pure and Applied Geophysics》2016,173(9):3085-3102

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Introduction Ice Fog,Ice Clouds,and Remote Sensing     

Ismail Gultepe  Andrew J. Heymsfield 《Pure and Applied Geophysics》2016,173(9):2977-2982

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Morphological records of storm floods exemplified by the impact of the 1872 Baltic storm on a sandy spit system in south‐eastern Denmark          下载免费PDF全文

Lars B. Clemmensen  Mette Bendixen  Mikkel U. Hede  Aart Kroon  Lars Nielsen  Andrew S. Murray 《地球表面变化过程与地形》2014,39(4):499-508

Beach‐ridge systems are important geo‐archives providing evidence for past wave climate including catastrophic storm flood events. This study investigates the morphological impacts of the 1872 Baltic storm flood on a beach‐ridge system (sandy spit) in south‐eastern Denmark and evaluates the frequency of extreme storm flood events in the area over a longer time perspective. This paper combines field studies of morphology and sedimentary deposits, studies of historical maps, digital terrain model, ground‐penetrating radar profiles, and luminescence dating. Sea water reached 2.8 m above mean sea level (amsl) during peak inundation and, based on studies of the morphological impacts of the 1872 storm flood, the event can be divided into four phases. Phase 1: increasing mean water levels and wave activity at the beach brought sediments from the beach (intertidal bars and normal berm) higher up in the profile and led to the formation of a storm‐berm. Phase 2: water levels further increased and sediment in the upper part of the profile continued to build up the storm‐berm. Phase 3: water levels now reached the top of the dune ridge and were well above the storm‐berm level. Sea water was breaching the dune ridge at several sites and wash‐over fans were generated until a level where the mean water level had dropped too much. Phase 4: the non‐vegetated wash‐over fans functioned as pathways for aeolian sand transport and relatively high dunes were formed in particular along the margins of the fan where aeolian sand was trapped by existing vegetation. The studied beach‐ridge system records about 4500 years of accumulation; the storm flood sediments described are unique suggesting that the 1872 Baltic storm flood event was an extreme event. Thus studies of beach‐ridge systems form a new source for understanding storm surge risk. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

Tracking sediment provenance and erosional evolution of the western Greater Caucasus          下载免费PDF全文

Giovanni Vezzoli  Eduardo Garzanti  Stephen J. Vincent  Sergio Andò  Andrew Carter  Alberto Resentini 《地球表面变化过程与地形》2014,39(8):1101-1114

This article investigates landscape characteristics and sediment composition in the western Greater Caucasus by using multiple methods at different timescales. Our ultimate goal is to compare short‐term versus long‐term trends in erosional processes and to reconstruct spatio‐temporal changes in sediment fluxes as controlled by partitioning of crustal shortening and rock uplift in the orogenic belt. Areas of active recent uplift are assessed by quantitative geomorphological techniques [digital elevation model (DEM) analysis of stream profiles and their deviation from equilibrium] and compared with regions of rapid exhumation over longer time intervals as previously determined by fission‐track and cosmogenic‐nuclide analyses. Complementary information from petrographic and heavy‐mineral analyses of modern sands and ancient sandstones is used to evaluate erosion integrated throughout the history of the orogen. River catchments displaying the highest relief, as shown by channel‐steepness indices, correspond with the areas of most rapid exhumation as outlined by thermochronological data. The region of high stream gradients is spatially associated with the highest topography around Mount Elbrus, where sedimentary cover strata have long been completely eroded and river sediments display the highest metamorphic indices and generally high heavy‐mineral concentrations. This study reinforces the suggestion that the bedrock–channel network can reveal much of the evolution of tectonically active landscapes, and implies that the controls on channel gradient ultimately dictate the topography and the relief along the Greater Caucasus. Our integrated datasets, obtained during a decade of continuing research, display a general agreement and regularity of erosion patterns through time, and consistently indicate westward decreasing rates of erosional unroofing from the central part of the range to the Black Sea. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

Airflow and aeolian sediment transport patterns within a coastal trough blowout during lateral wind conditions   总被引：5，自引：0，他引：5       下载免费PDF全文

Thomas Andrew George Smyth  Derek Jackson  Andrew Cooper 《地球表面变化过程与地形》2014,39(14):1847-1854

Blowouts are depressions that occur on coastal dunes, deserts and grasslands. The absence of vegetation in blowouts permits high speed winds to entrain and remove sediment. Whereas much research has examined patterns of wind flow and sediment transport on the stoss slopes and lee of sand dunes, no study has yet investigated the connections between secondary air‐flow structures and sediment transport in a blowout where zones of streamline compression, expansion and steering are less clearly delineated. In this study we investigated the variability of sediment flux and its relation to near‐surface wind speed and turbulence within a trough blowout during wind flow that was oblique to the axis of the blowout. Wind flow was measured using six, three‐dimensional (3D) ultrasonic anemometers while sediment flux by eight sand traps, all operating at 25 Hz. Results demonstrated that sediment flux rates were highly variable throughout the blowout deflation basin, even over short distances (< 0.5 m). Where flow was steadiest, flux was greatest. Consequently the highest rates of sediment transport were recorded on the erosional wall crest where flow was compressed and accelerated. The strength of correlation between sediment flux and wind parameter improved with an increase in averaging interval, from 10 seconds to 1 minute. At an interval of 10 seconds, however, wind speed correlated best with flux at seven of eight traps, whereas at an interval of one minute Turbulent Kinetic Energy (TKE) provided the best correlation with flux at six of the eight traps. Correlation between sediment flux and wind parameters was best in the centre of the blowout and poorest on the erosional wall crest. The evidence from this paper suggests, for the first time, that TKE may be a better predictor of sediment transport at minute scale averaging intervals, particularly over landforms where wind flow is highly turbulent. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

Evapotranspiration and canopy characteristics of two lodgepole pine stands following mountain pine beetle attack   总被引：1，自引：0，他引：1       下载免费PDF全文

Mathew G. Brown  T. Andrew Black  Zoran Nesic  Vanessa N. Foord  David L. Spittlehouse  Arthur L. Fredeen  Rebecca Bowler  Nicholas J. Grant  Philip J. Burton  J. A. Trofymow  Dominic Lessard  Gesa Meyer 《水文研究》2014,28(8):3326-3340

Over the past decade, British Columbia (BC), has experienced the largest mountain pine beetle (MPB) outbreak on record. This study used the eddy‐covariance (EC) technique to examine the impact of the MPB attack on evapotranspiration (E) and associated canopy characteristics of two lodgepole pine stands with secondary structure (trees, saplings and seedlings surviving the attack) located in central BC. MPB‐06, an 85‐year‐old almost pure stand of pine trees, was first attacked in 2006, and by 2010, ~80% of the trees had been killed. MPB‐03, a 110‐year‐old stand with an overstory consisting of over 90% pine and a developed sub‐canopy, was first attacked in 2003 and by 2007 had > 95% pine canopy mortality. EC measurements began in August 2006 at MPB‐06 and in March 2007 at MPB‐03, and continued for four years. Annual total E ranged from 226 mm to 237 mm at MPB‐06, and from 280 to 297 mm at MPB‐03, showing relatively little year‐to‐year change at both sites over the four years. Increased E from the accelerated growth of the surviving vegetation (secondary structure, shrubs and herbs) compensated for reduction in E due to the death of the overstory. Monthly average daytime canopy conductance, the Priestley–Taylor (α), and the canopy–atmosphere decoupling coefficient (Ω) steadily increased during the growing season reaching approximate maximum values of 5 mm s^?1, 0.75 and 0.12, respectively. Potential evapotranspiration was approximated using a vapour pressure deficit‐dependent α obtained at high soil water content. Calculated water deficits indicated some water‐supply limitation to the surviving trees and understory at both sites. Rates of root zone drainage during the growing season were low relative to precipitation. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

Glyphosate persistence in seawater     

Philip Mercurio  Florita Flores  Jochen F. Mueller  Steve Carter  Andrew P. Negri 《Marine pollution bulletin》2014

Glyphosate is one of the most widely applied herbicides globally but its persistence in seawater has not been reported. Here we quantify the biodegradation of glyphosate using standard “simulation” flask tests with native bacterial populations and coastal seawater from the Great Barrier Reef. The half-life for glyphosate at 25 °C in low-light was 47 days, extending to 267 days in the dark at 25 °C and 315 days in the dark at 31 °C, which is the longest persistence reported for this herbicide. AMPA, the microbial transformation product of glyphosate, was detected under all conditions, confirming that degradation was mediated by the native microbial community. This study demonstrates glyphosate is moderately persistent in the marine water under low light conditions and is highly persistent in the dark. Little degradation would be expected during flood plumes in the tropics, which could potentially deliver dissolved and sediment-bound glyphosate far from shore.  相似文献   

Projected changes in reported campylobacteriosis and cryptosporidiosis rates as a function of climate change: a New Zealand study     

Graham McBride  Andrew Tait  David Slaney 《Stochastic Environmental Research and Risk Assessment (SERRA)》2014,28(8):2133-2147

Two pathogens whose reported incidence rates may alter under climate change and variability were selected for study: the bacterium Campylobacter and the protozoan oocyst Cryptosporidium. Both are of particular importance in New Zealand, given its extensive and intensive agricultural farming systems, and therefore to other agriculturally-based economies. Local and international studies have indicated that rates of illnesses associated with these pathogens (campylobacteriosis and cryptosporidiosis) may increase as temperature rises and as rainfall becomes more intense. An existing calibrated linear SIR (Susceptible-Ill-Recovered) model was used to make predictions of the proportional change in the reported rates of these two zoonoses. This method uses analytical solutions of the SIR model and a simple exponential approach to describe the temporal changes in pathogen contact rates—and hence of reported disease rates. These changes reflect climate change impacts only and do not consider adaptation or mitigation measures. Projections cannot be made of the actual-but-unknown-illness rates because of under-reporting throughout the country. The SIR model outputs provide projected changes in reported disease incidence as a function of temperature and rainfall for the years 2015, 2040 and 2090. These are calculated for three climate change scenarios: low (B1), medium (A1B) and high (A2) emissions of greenhouse gases and for four seasons. Projections show the potential for substantial changes in reported rates by the year 2090 across New Zealand, with children most at-risk. Maximum increases in reported illness rates tend to occur in summer when pathogen contact rates are greatest. Average annual rates of increase of reported campylobacteriosis are predicted to rise by as much as 20 % and by 36 % for cryptosporidiosis (children, A2 scenario, 2090). To our knowledge, this is the first time that SIR modelling has been coupled with climate change projections.  相似文献   

Unified global and regional wave model on a multi-resolution grid   总被引：1，自引：1，他引：0  

Jian-Guo Li  Andrew Saulter 《Ocean Dynamics》2014,64(11):1657-1670

Models for ocean surface wave forecasting in weather centres comprise global and regional systems in order to efficiently meet service demands. Regional models cannot run alone and have to use large area or global models to provide boundary wave spectra. The modern two-way nesting technique is to run the two models together with the regional model domain covered by both resolutions. An alternative method is to use a single multi-resolution grid that fits irregular coastlines and provides refined resolutions in selected regions. This paper presents a multi-resolution model based on a spherical multiple-cell (SMC) grid, which is designed to relax the CFL restriction of Eulerian advection time step at high latitudes by merging the conventional latitude-longitude grid cells. The implementation of the SMC grid in WAVEWATCH III is described, and a multi-resolution (6, 12 and 25 km) global SMC configuration is compared with a suite of nested grid ocean surface wave models, including 35-km global, 8-km European and 4-km UK regional models. Verification against buoy and platform wave observations indicates that the unified model is better than the 35-km global and very close in performance to the two regional models.  相似文献   

A typology of dairy farmer perceptions towards climate change   总被引：2，自引：2，他引：0  

Andrew P. Barnes  Luiza Toma 《Climatic change》2012,112(2):507-522

Dairy farming is an industry which could potentially mitigate a large amount of greenhouse gas emissions. However, perception and acceptance towards climate change is a significant barrier to voluntary adoption of best practice techniques. A number of countries have set targets for reducing emissions, of which Scotland has one of the most ambitious agendas. This paper presents results from an extensive survey of 540 dairy farmers, conducted in 2009, with the aim of understanding attitudes, values and intentions towards climate change. Only half of these farmers agreed that temperatures would rise in the future and this could significantly hinder adoption of voluntary measures to meet emissions targets. To explore this further a typology was developed on the responses to attitude and value statements, using principal components and cluster analysis methods. Six distinct types were found to exist which had a range of outlooks towards the impact of climate change in the future. However, five of the six types stated no intention to adopt practices which would reduce emissions. The typology approach supports diversified engagement strategies and a more innovation-led or resource maximisation view towards farming was expressed by several of these types. This may indicate that policy makers should focus on ‘win-win’ technologies as a means to effectively engage with these. However, a number of types were disengaged from the process which was driven by uncertainties towards projections for global warming and this needs to be addressed by both scientists and policy makers to ensure greater participation within the farming community.  相似文献