Ontario Ministry of Transportation

About: Ontario Ministry of Transportation is a government organization based out in Toronto, Ontario, Canada. It is known for research contribution in the topics: Poison control & Asphalt. The organization has 4652 authors who have published 3882 publications receiving 59011 citations.

Dynamics of sediment resuspension and the conceptual schema of nutrient release in the large shallow Lake Taihu, China

Abstract: On the basis of investigationsin situ, it was found that mass exchange on the water-sediment interface occurred chiefly on the superficial sediment within 5–10 cm. The spatial physicochemical character of sediment was distributed uniformly. The observation of lake currents and waves indicated that the dynamic sources, which act on the interface of water and sediment, came mainly from waves under strong wind forcing, while the critical shear stresses due to the waves and currents were of the same magnitude under weak wind forcing. The critical shear stress that leads to extensive sediment resuspension was about 0.03 – 0.04N/m2, equivalent to a wind speedin situ up to 4 m/s. If a dynamic intensity exceeded the critical shear stress, such as a wind velocity up to 6.5 m/s, massive sediment re-suspension would be observed in the lake. Furthermore, field investigations revealed that the nutrient concentration of pore water within the sediment was far greater than that of overlaying water, which provides objective conditions for the nutrient release from sediment. According to nutrient analyses in the pore water from the superficial 5–10 cm sediments, a severe dynamic process in the Taihu Lake would bring out a peak nutrient release, i.e. a 0.12 mg/L increase of TN, and 0.005 mg/L increase of TP in the lake. In the end, a general scheme of nutrient release from sediment in large shallow lakes was put forward: when the wind-driven forcing imposes on the lake, it will make the sediment resuspension. At the same time, the nutrition from the pore water will follow the sediment resuspension release to overlaying water. Because of oxidation of solid particulates when it resuspends from sediment, the disturbance of hydrodynamics will enhance the suspension particulates absorbing nutrition. After the withdrawal of wind forcing, the suspended mass would deposit and bring part of the released nutrients back into sediment. The degraded organic particulate would be separated to the pore water within the sediment under the condition of deposition, and wait for the next wind forcing.

Dispersal phenology of hydrochorous plants in relation to discharge, seed release time and buoyancy of seeds: the flood pulse concept supported

Abstract: 1 Restored floodplains and backwaters lacking a viable propagule bank, may need flood pulses to facilitate inward dispersal of diaspores. Temporal patterns of hydrochorous plant dispersal are, however, not well known. 2 Diversity and abundance of diaspores dispersed in a water body over 12 months were quantified using a 200 mum net in order to: (i) test for a relationship between discharge and the number of species and diaspores dispersed; (ii) examine the effect of seed buoyancy and seed release period on the length of the dispersal period; and (iii) test whether diaspores of species that disperse during a similar period of the year are characterized by similar dispersal and dormancy traits. 3 A total 359 188 individuals of 174 vascular species developed from 144 samples, with most (90%) from vegetative diaspores and only 10% from seeds. Mean number of species and diaspores varied between months in parallel with discharge levels. Stepwise multiple regression analysis showed that both seed buoyancy and seed release influenced dispersal periods. 4 In general, species that dispersed most diaspores in spring and summer had non-dormant seeds, a shorter seed release period and a shorter seed dispersal period than species whose dormant seeds dispersed in autumn and winter. Vegetative diaspores were dispersed on average over 8 months, indicating their importance to long-distance dispersal. Several species dispersed both generative and vegetative diaspores, often in different seasons. 5 Our results may assist the planning of regenerative processes in riverine wetlands at landscape scales, as dispersal phenology, and discharge rates must be taken into consideration. Vegetative diaspores may be more important than seeds, although the latter may extend the species dispersal period into other seasons. Temporal heterogeneity in diaspore dispersal influences the identity of diaspores reaching restored habitats.

New wave pressure formulae for composite breakwaters

Abstract: A proposal is made for new wave pressure formulae, which can be applied for the whole ranges of wave action from nonbreaking to postbreaking waves with smooth transition between them. The design wave height is specified as the maximum wave height possible at the site of breakwater. The new formulae as well as the existing formulae of Hiroi, Sainflou, and Minikin have been calibrated with the cases of 21 slidings and 13 nonslidings of the upright sections of prototype breakwaters. The calibration establishes that the new formulae are the most accurate ones.

Development of an updated global land In situ‐based data set of temperature and precipitation extremes : HadEX3

Abstract: Robert Dunn was supported by the Met Office Hadley Centre Climate Programme funded by BEIS and Defra (GA01101) and thanks Nick Rayner and Lizzie Good for helpful comments on the manuscript Lisa Alexander is supported by the Australian Research Council (ARC) Grants DP160103439 and CE170100023 Markus Donat acknowledges funding by the Spanish Ministry for the Economy, Industry and Competitiveness Ramon y Cajal 2017 Grant Reference RYC‐2017‐22964 Mohd Noor'Arifin Bin Hj Yussof and Muhammad Khairul Izzat Bin Ibrahim thank the Brunei Darussalam Meteorological Department (BDMD) Ying Sun was supported by China funding agencies 2018YFA0605604 and 2018YFC1507702 Fatemeh Rahimzadeh and Mahbobeh Khoshkam thank IR of Iranian Meteorological Organization (IRIMO) and the Atmospheric Science and Meteorological Organization Research Center (ASMERC) for Data and also sharing their experiences, especially Abbas Rangbar Jose Marengo was supported by the National Institute of Science and Technology for Climate Change Phase 2 under CNPq Grant 465501/2014‐1, FAPESP Grants 2014/50848‐9 and 2015/03804‐9, and the National Coordination for High Level Education and Training (CAPES) Grant 88887136402‐00INCT The team that worked on the data in West Africa received funding from the UK's National Environment Research Council (NERC)/Department for International Development DFID) Future Climate For Africa programme, under the AMMA‐2050 project (Grants NE/M020428/1 and NE/M019969/1) Data from Southeast Asia (excl Indonesia) was supported by work on using ClimPACT2 during the Second Workshop on ASEAN Regional Climate Data, Analysis and Projections (ARCDAP‐2), 25–29 March 2019, Singapore, jointly funded by Meteorological Service Singapore and WMO through the Canada‐Climate Risk and Early Warning Systems (CREWS) initiative This research was supported by Thai Meteorological Department (TMD) and Thailand Science Research and Innovation (TSRI) under Grant RDG6030003 Daily data for Mexico were provided by the Servicio Meteorologico Nacional (SMN) of Comision Nacional del Agua (CONAGUA) We acknowledge the data providers in the ECA&D project (https://wwwecadeu), the SACA&D project (https://saca-bmkgknminl), and the LACA&D project (https://ciifenknminl) We thank the three anonymous reviewers for their detailed comments which improved the manuscript