Nitrite distribution in Peru current waters

Studies of the nitrite-nitrogen distribution off the western coast of South America have shown significant concentrations in surface waters (up to 0.5 µg-at/l) and a widespread primary maximum near the top of the thermocline. Below the surface layer, where the oxygen minimum contains less than 0.2 ml/l of dissolved oxygen, a secondary maximum was present south of 10°S, within 1000 km of the coast...

Redefinition of salinity

Two definitions of salinity have been in use since the early part of the present century (Knudsen 1901, Forch et al. 1902). According to the procedural definition, salinity is the amount (in grams) of dissolved solid material in a kilogram of seawater after all the bromine has been replaced by an equivalent quantity of chlorine, after all the carbonate has been converted to oxide, and after all of the organic matter has been destroyed...

An Overview of the Use of the SimSphere Soil Vegetation Atmosphere Transfer (SVAT) Model for the Study of Land-Atmosphere Interactions

Soil Vegetation Atmosphere Transfer (SVAT) models consist of deterministic mathematical representations of the physical processes involved between the land surface and the atmosphere and of their interactions, at time-steps acceptable for the study of land surface processes. The present article provides a comprehensive and systematic review of one such SVAT model suitable for use in mesoscale or boundary layer studies, originally developed by [1]. This model, which has evolved significantly both architecturally and functionally since its foundation, has been widely applied in over thirty interdisciplinary science investigations, and it is currently used as a learning resource for students in a number of educational institutes globally. The present review is also regarded as very timely, since a variation of a method using this specific SVAT model along with satellite observations is currently being considered in a scheme being developed for the operational retrieval of soil surface moisture by the US National Polar-orbiting Operational Environmental Satellite System (NPOESS), in a series of satellites that are due to be launched from 2016 onwards

Ugnu pilot area - simulation model and sensitivity analysis

Master's Project (M.S.) University of Alaska Fairbanks, 2020Collaborating with Hilcorp Alaska, LLC, the Ugnu pilot area is the subject of this project. Hilcorp Alaska is conducting field pilot test at Milne Point Field to prove commerciality with Ugnu heavy oil as well as an on-going Milne viscous oil polymer flood field pilot test in the Schrader Bluff sands. The Ugnu sand heavy oil represents much of the heavy oil on Alaska’s North Slope and has potential for future development. Typical heavy oil has a viscosity of 1,000 - 10,000 centipoise, approximately akin to viscosities of honey and molasses, respectively. North Slope heavy oil is located around 3,000-foot depths and typically overlays existing fields. The project involves a reservoir simulation model and sensitivity analysis to support developmental drilling plans from a Milne Point Unit pad. Necessary geologic and reservoir properties were provided for usage in this project by Hilcorp. Production data was provided for history matching. Field geologic background was also supplied to aid in the understanding of the reservoir. The reservoir simulation model was built using Computer Modelling Group software, namely Builder and IMEX. The first model iteration contained one producer in an 8,500-foot lateral pattern. Further iterations included additional producers and injectors for waterflood and polymer flood studies. Conclusions and recommendations were drawn upon analyzing the reservoir simulation results centering around favorable production strategies, polymer flood performance, comparison to the on-going Milne viscous oil polymer flood pilot, and future polymer flood studies. Completed objectives of this project included: 1. Developing a numerical reservoir simulation model for the Ugnu MB sand in the pilot area; 2. Evaluating the productivity of horizontal wells in the Ugnu MB sand; 3. Predicting ultimate oil recovery with waterflood and polymer flood; 4. Predicting polymer utilization, polymer injected per incremental oil barrels over waterflood

Fluxes and distribution of dissolved iron in the eastern (sub-) tropical North Atlantic Ocean

Aeolian dust transport from the Saharan/Sahel desert regions is considered the dominant external input of iron (Fe) to the surface waters of the eastern (sub-) tropical North Atlantic Ocean. To test this hypothesis, we investigated the sources of dissolved Fe (DFe) and quantified DFe fluxes to the surface ocean in this region. In winter 2008, surface water DFe concentrations varied between <0.1 nM and 0.37 nM, with an average of 0.13 ± 0.07 nM DFe (n = 194). A strong correlation between mixed layer averaged concentrations of dissolved aluminum (DAl), a proxy for dust input, and DFe indicated dust as a source of DFe to the surface ocean. The importance of Aeolian nutrient input was further confirmed by an increase of 0.1 nM DFe and 0.05 ?M phosphate during a repeat transect before and after a dust event. An exponential decrease of DFe with increasing distance from the African continent, suggested that continental shelf waters were a source of DFe to the northern part of our study area. Relatively high Fe:C ratios of up to 3 × 10?5 (C derived from apparent oxygen utilization (AOU)) indicated an external source of Fe to these African continental shelf waters. Below the wind mixed layer along 12°N, enhanced DFe concentrations (>1.5 nM) correlated positively with apparent oxygen utilization (AOU) and showed the importance of organic matter remineralization as an DFe source. As a consequence, vertical diffusive mixing formed an important Fe flux to the surface ocean in this region, even surpassing that of a major dust event

New fire diurnal cycle characterizations to improve fire radiative energy assessments made from low-Earth orbit satellites sampling

Accurate near real time fire emissions estimates are required for air quality forecasts. To date, most approaches are based on satellite-derived estimates of fire radiative power (FRP), which can be converted to fire radiative energy (FRE) which is directly related to fire emissions. Uncertainties in these FRE estimations are often substantial. This is for a large part because the most often used low-Earth orbit satellite-based instruments like the MODerate-resolution Imaging Spectroradiometer (MODIS) have a relatively poor sampling of the usually pronounced fire diurnal cycle. In this paper we explore the spatial variation of this fire diurnal cycle and its drivers. Specifically, we assess how representing the fire diurnal cycle affects FRP and FRE estimations when using data collected at MODIS overpasses. Using data assimilation we explored three different methods to estimate hourly FRE, based on an incremental sophistication of parameterizing the fire diurnal cycle. We sampled data from the geostationary Meteosat Spinning Enhanced Visible and Infrared Imager (SEVIRI) at MODIS detection opportunities to drive the three approaches. The full SEVIRI time-series, providing full coverage of the diurnal cycle, were used to evaluate the results. Our study period comprised three years (2010–2012), and we focussed on Africa and the Mediterranean basin to avoid the use of potentially lower quality SEVIRI data obtained at very far off-nadir view angles. We found that the fire diurnal cycle varies substantially over the study region, and depends on both fuel and weather conditions. For example, more "intense" fires characterized by a fire diurnal cycle with high peak fire activity, long duration over the day, and with nighttime fire activity are most common in areas of large fire size (i.e., large burned area per fire event). These areas are most prevalent in relatively arid regions. Ignoring the fire diurnal cycle as done currently in some approaches caused structural errors, while generally overestimating FRE. Including information on the climatology of the fire diurnal cycle provided the most promising avenue to improve FRE estimations. This approach also improved the performance on relatively high spatiotemporal resolutions, although only when aggregating model results to coarser spatial and/or temporal scale good correlation was found with the full SEVIRI hourly reference dataset. In general model performance was best in areas of frequent fire and low errors of omission. We recommend the use of regionally varying fire diurnal cycle information within the Global Fire Assimilation System (GFAS) used in the Copernicus Atmosphere Monitoring Services, which will improve FRE estimates and may allow for further reconciliation of biomass burning emission estimates from different inventories

Outcomes of an Inner City Forensic Intellectual Disability Service

Introduction National policy in England is now directed towards keeping patients with intellectual disability (ID) presenting with forensic problems for time limited treatment. The result is that secure hospital services are expected to work much more proactively to discharge patients to community-based services. However, there is little evidence in recent years on the outcome of discharged patients with ID from secure hospitals. This study describes the outcomes of a patient group discharged from a specialist forensic ID service in London, England. Method This is a descriptive retrospective case note study of patients with ID admitted to and discharged from a secure service with both low and medium secure wards, over a six-year period from 2009 to 2016. The study examined patient demographic, clinical and outcome variables, including length of stay, pharmacological treatment on admission and discharge, offending history, and readmissions to hospital and re-offending following discharge. Results The study identified 40 male patients, 29 of which were admitted to the medium secure ward. 27 patients (67.5%) were discharged into the community with 14 patients having sole support from the community intellectual disability services and four from the community forensic services. 20% of patients were readmitted within the study period and 22.2% of patients received further convictions via the Criminal Justice System following discharge. Conclusion This was a complex group of patients with ID discharged into the community with a number at risk of requiring readmission, and of reoffending. Community based services providing for offenders with ID must have sufficient expertise and resourcing to manage the needs of such a patient group including the ongoing management of risks. The national drive is significantly to reduce the availability of specialist in-patient services for this group of patients but this must occur alongside an increase in both resources and expertise within community services. This article is to be published in the Journal of Intellectual Disabilities and Offending Behaviour http://www.emeraldinsight.com/journal/jido