Seasonal Forecasts of the Summer 2016 Yangtze River Basin Rainfall   总被引：1，自引：0，他引：1  

Philip E.BETT  Adam A.SCAIFE  Chaofan LI  Chris HEWITT  Nicola GOLDING  Peiqun ZHANG  Nick DUNSTONE  Doug M.SMITH  Hazel E.THORNTON  Riyu LU  Hong-Li REN 《大气科学进展》2018,35(8):918-926

The Yangtze River has been subject to heavy flooding throughout history,and in recent times severe floods such as those in 1998 have resulted in heavy loss of life and livelihoods.Dams along the river help to manage flood waters,and are important sources of electricity for the region.Being able to forecast high-impact events at long lead times therefore has enormous potential benefit.Recent improvements in seasonal forecasting mean that dynamical climate models can start to be used directly for operational services.The teleconnection from El Ni ?no to Yangtze River basin rainfall meant that the strong El Ni ?no in winter 2015/16 provided a valuable opportunity to test the application of a dynamical forecast system.This paper therefore presents a case study of a real-time seasonal forecast for the Yangtze River basin,building on previous work demonstrating the retrospective skill of such a forecast.A simple forecasting methodology is presented,in which the forecast probabilities are derived from the historical relationship between hindcast and observations.Its performance for2016 is discussed.The heavy rainfall in the May–June–July period was correctly forecast well in advance.August saw anomalously low rainfall,and the forecasts for the June–July–August period correctly showed closer to average levels.The forecasts contributed to the confidence of decision-makers across the Yangtze River basin.Trials of climate services such as this help to promote appropriate use of seasonal forecasts,and highlight areas for future improvements.  相似文献   

Time‐scale analysis of marine boundary layer aerosol evolution: Lagrangian case studies under clean and polluted cloudy conditions     

Claudia Hoell  Colin O'Dowd  Simon Osborne  Doug Johnson 《Tellus. Series B, Chemical and physical meteorology》2000,52(2):423-438

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Boundary layer and aerosol evolution during the 3rd Lagrangian experiment of ACE‐2     

Robert Wood  Doug Johnson  Simon Osborne  Meinrat O. Andreae  Brain Bandy  Timothy S. Bates  Colin O'Dowd  Paul Glantz  Kevin Noone  Patricia K. Quinn  Jochen Rudolph  Karsten Suhre 《Tellus. Series B, Chemical and physical meteorology》2000,52(2):401-422

Aircraft measurements are presented of the Lagrangian evolution of a marine boundary layer over a 30‐h period during the ACE‐2 field campaign. At the start of the observational period, a 500‐m deep polluted marine internal boundary layer (MIBL) was overlain by the remnants of a polluted continental boundary layer extending to around 2 km below a clean, dry free troposphere. The MIBL grew rapidly to a thickness of 900–1000 m in response to increasing sea surface temperatures. No significant aerosol spectral evolution was observed in the boundary layer. Low concentrations of SO₂ were observed in the MIBL suggesting that the air mass contained relatively aged aerosol. Aerosol spectra show a broad mode with a modal diameter of around 0.1μm. The polluted layer between the MIBL and the unpolluted free troposphere was only weakly and intermittently turbulent which prevented significant entrainment of clean air into the polluted layer from aloft. The polluted layer depth was thus controlled mainly by subsidence which as a result becomes shallower, decreasing from over 2000 m to around 1200 m during the observational period. The aerosol characteristics of the polluted layer were similar to those in the MIBL and so although the MIBL entrained considerable amounts of air from above the MIBL the aerosol characteristics underwent no significant change. This has important implications for the rate at which a polluted continental air mass is converted to a clean marine one. The dataset should prove useful in the validation of the modelling of continental pollution outbreaks.  相似文献   

Three-dimensional slope stability analysis of South Peak, Crowsnest Pass, Alberta, Canada   总被引：2，自引：2，他引：0  

Marc-Andr�� Brideau  Andrea Pedrazzini  Doug Stead  Corey Froese  Michel Jaboyedoff  David van Zeyl 《Landslides》2011,8(2):139-158

South Peak is a 7-Mm³ potentially unstable rock mass located adjacent to the 1903 Frank Slide on Turtle Mountain, Alberta. This paper presents three-dimensional numerical rock slope stability models and compares them with a previous conceptual slope instability model based on discontinuity surfaces identified using an airborne LiDAR digital elevation model (DEM). Rock mass conditions at South Peak are described using the Geological Strength Index and point load tests, whilst the mean discontinuity set orientations and characteristics are based on approximately 500 field measurements. A kinematic analysis was first conducted to evaluate probable simple discontinuity-controlled failure modes. The potential for wedge failure was further assessed by considering the orientation of wedge intersections over the airborne LiDAR DEM and through a limit equilibrium combination analysis. Block theory was used to evaluate the finiteness and removability of blocks in the rock mass. Finally, the complex interaction between discontinuity sets and the topography within South Peak was investigated through three-dimensional distinct element models using the code 3DEC. The influence of individual discontinuity sets, scale effects, friction angle and the persistence along the discontinuity surfaces on the slope stability conditions were all investigated using this code.  相似文献   

Fundamental differences between SPH and grid methods   总被引：1，自引：0，他引：1  

Oscar Agertz  Ben Moore  Joachim Stadel  Doug Potter  Francesco Miniati  Justin Read  Lucio Mayer  Artur Gawryszczak  rey Kravtsov  Åke Nordlund  Frazer Pearce  Vicent Quilis  Douglas Rudd  Volker Springel  James Stone  Elizabeth Tasker  Romain Teyssier  James Wadsley  Rolf Walder 《Monthly notices of the Royal Astronomical Society》2007,380(3):963-978

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Young star clusters immersed in intermediate-age fields in the Small Magellanic Cloud     

Andrés E. Piatti  Ata Sarajedini  Doug Geisler  David Clark  Juan Seguel 《Monthly notices of the Royal Astronomical Society》2007,377(1):300-316

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What do hydrologists mean when they use the term flushing?     

Doug Burns 《水文研究》2005,19(6):1325-1327

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Solar terminator and auroral sources for traveling ionospheric disturbances in the midlatitude F region     

J.W. MacDougall  P.T. Jayachandran 《Journal of Atmospheric and Solar》2011,73(17-18):2437-2443

The occurrence of Traveling Ionospheric Disturbances (TIDs) at a midlatitude location (London, Canada, 43°N, 81°W) has been examined using data recorded by standard 5 min ionograms during the year 2000. It is found that the dominant source of TIDs during daytime appears to be the sunrise terminator but during nighttime the sunset terminator and magnetic disturbances both contribute to the TIDs. The daytime TIDs show a weak semiannual variation with maxima in solstices. The nighttime TIDs show insignificant annual variation.  相似文献   

Identification of sorption processes and parameters for radionuclide transport in fractured rock     

Zhenxue Dai  Andrew Wolfsberg  Paul Reimus  Hailin Deng  Edward Kwicklis  Mei Ding  Doug Ware  Ming Ye 《Journal of Hydrology》2012

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Using GRASS GIS to Model Solar Irradiation on North Carolina Aquatic Habitats with Canopy Data     

Doug Newcomb 《Transactions in GIS》2012,16(2):161-176

Sunlight can have a significant impact on freshwater aquatic communities. Using 64‐ bit GRASS, a previously generated 18.2 m resolution forest canopy height grid for the State of North Carolina was used as a base elevation layer for calculation of 18.2 m resolution total irradiance (Watt‐hours/square meter/day) grids for 365 days of the year. Daily calculations were aggregated annually and overlaid on rasterized 1:24,000‐scale USGS hydrology with canopy type and seasonal filters to quantify annual solar irradiation input to streams and rivers in North Carolina. Bare earth calculations of solar irradiation for the aquatic habitats were compared to the canopy filtered calculations. There was substantially less solar irradiation in aquatic habitats under the canopy filtered model. Total solar irradiation for subbasins created from point locations of occurrences of Dwarf wedgemussel (Alasmidonta heterodon) were compared with total solar irradiation for watersheds created from locations with no mussels for the full subbasin, 1 km, and 500 m upstream from the sampling point. There was no significant difference in the amount of total solar irradiation modeled for the subbasins with Dwarf wedgemussel and watersheds with no mussels.  相似文献