TOPEX/Poseidon and Jason Equatorial Sea Surface Slope Anomaly in the Atlantic in 2002: Comparison with Wind and Current Measurements at 23W

A time series of velocity profile in the upper 150 m of the equatorial Atlantic was gathered at 23W in 2002 within the PIRATA program. It constitutes the first time series of near surface current measurements simultaneous with altimetric data in the equatorial Atlantic. The surface slope anomaly along the equator is computed from satellite altimetry, and, as a proxy for the pressure gradient along the equator, compared with the wind and near surface current data. In a first step, a time series of the surface slope anomaly along the equator in the Atlantic is computed from the 10-year-long TOPEX/Poseidon sea level anomalies. A sensitivity study establishes the robustness of the calculation. Apart from a 15 cm bias, the equatorial sea surface slope anomalies estimated either from TOPEX/Poseidon or from Jason over the 6-month overlap (Feb.-Aug. 2002) do not reveal drastic differences. We produce two sea surface slope anomaly composite time series for 2002 (one with T/P data, the other with Jason data during the commissioning phase) and compare them to the wind and velocity data at 23W. As expected, the near surface velocity and depth of the upper limit of the equatorial undercurrent (EUC) are extremely well correlated with the surface pressure gradient anomaly. 10-year-long time series of altimetry-derived zonal sea surface slope anomaly and ECMWF ERA40 wind stress are also well correlated. They exhibit similar spectral content and similar anomalous years. This is a first step towards a full analysis of the EUC dynamics using altimetry, PIRATA data (near surface current and subsurface thermohaline structure) and model. These initial comparisons reinforce the utility of Jason measurements for continuing the 10-year and highly accurate TOPEX/Poseidon time series for study of equatorial signals.     

Lung function in subjects exposed to crude oil spill into sea water

A Greek oil-tanker ran aground, resulting in a huge oil spill along the costal areas of Karachi, Pakistan. The purpose of this study was to assess the lung function and follow up change after one year in subjects exposed to crude oil spill in sea water. It was a cross sectional study with follow up in 20 apparently healthy, non-smoking, male workers, who were exposed to a crude oil spill environment during oil cleaning operation. The exposed group was matched with 31 apparently healthy male control subjects. Pulmonary function test was performed using an electronic Spirometer. Subjects exposed to polluted air have significant reduction in forced vital capacity (FVC), forced expiratory volume in first second (FEV(1)), forced expiratory flow (FEF(25-75%)) and maximum voluntary ventilation (MVV) compared to their matched controls. This impairment was reversible and lung functions parameters were improved when the subjects were withdrawn from the polluted air environment.     

Stream flow variability and drought severity in the Songhua River Basin,Northeast China

A slight variation in the magnitude of stream flow can have a substantial influence on the development of water resources. The Songhua River Basin (SRB) serves as a major grain commodity basin and is located in the northeastern region of China. Recent studies have identified a gradual decrease in stream flows, which presents a serious risk to water resources of the region. It is therefore necessary to assess the variation in stream flow and to predict the future of stream flows and droughts to make a comprehensive plan for agricultural irrigation. The simulation of monthly stream flows and the investigation of the influence of climate on the stream flow in the SRB were performed by utilizing the Integrated Water Evaluation and Planning (WEAP) tool coupled with observed precipitation data, as well as the Asian Precipitation-Highly-Resolved Observational Data Integration towards Evaluation of Water Resources (APHRODITE’s Water Resources) precipitation product. The Nash–Sutcliffe coefficient (NSC) was used to assess the WEAP efficiency. During the time of calibration, NSC was obtained as 0.90 and 0.67 using observed and APHRODITE precipitation data, respectively. The results indicate that WEAP can be used effectively in the SRB. The application of the model suggested a maximum decline in stream flow, reaching 24% until the end of 21st century under future climate change scenarios. The drought indices (standardized drought index and percent of normal index) demonstrated that chances of severe to extreme drought events are highest in 2059, 2060 and 2085, while in the remaining time period mild to moderate drought events may occur in the entire study area. The drought duration, severity and intensity for the period of 2011–2099 under all scenarios, [(A1B: 12, ? 1.55, ? 0.12), (A2: 12, ? 1.41, ? 0.09), (max. wetting and warming conditions: 12, ? 1.37, ? 0.11) and (min. wetting and warming conditions: 12, ? 1.69, ? 0.19)], respectively.     

Trace element soil contamination from smelters in the Illawarra region,New South Wales,Australia

Boundaries of densely populated areas can approach with time to old subsurface repositories of radioactive waste due to growth of settlement territories. P     

Spatio‐temporal analysis of glacial ice area distribution of Hunza River Basin,Karakoram region of Pakistan

There is a high degree of uncertainty about the state and fate of Pakistan's Karakoram glaciers due to data scarcity in high altitude regions. They are thought to be less vulnerable to climatic change because they behave differently as compared with eastern Himalayas. This study measures the decadal temporal changes in the glacial ice area of Karakoram's Hunza River Basin, one of the eight subbasins of Upper Indus Basin. An attempt has been made to investigate the relationship between glacial ice area changes and calculated values of precipitation, temperature and run‐off. A combination of satellite and field‐based approach is applied. Output includes maps of glacial ice hypsometries of eight glacial ice subregions of Hunza River Basin for 3 years (i.e., 1989, 2002, and 2010). The results show a decreasing trend in the glacial ice‐covered area signifying a reduction of 20.47% with the largest reduction being in the lower elevation bands. There is presently no conclusive answer as to why glacial ice in the Karakoram is acting differently from the near‐global indication of glacial ice changes. Climate data from high altitudes are needed to find answer for this anomalous behaviour.     

Biodegradation of crude oil and n-alkanes by fungi isolated from Oman

Ten fungal species isolated from tar balls collected from the beaches of Oman were tested for their abilities to grow and degrade n-alkanes and crude oil. The abilities of Aspergillus niger, A. ochraceus and Penicillium chrysogenum to degrade n-alkanes (C13-C18), crude oil were compared and their mycelial biomass was measured. Significant differences were found in the utilization of C15, C16, C17 and C18 by the three fungi. Similarly, significant differences we found in the amount of biomass produced by the three fungi growing on C13, C17, C18 and crude oil. The correlation coefficient of biomass and oil utilization was not statistically significant for Aspergillus niger, significant for Aspergillus terreus and highly significant for P. chrysogenum.     

Significance of enhanced infiltration due to groundwater extraction on the disappearance of a headwater lagoon system: Toluca Basin, Mexico

Mexico City relies significantly on groundwater resources drawn from the Sistema Lerma well field located in the Toluca Basin, Mexico. Enhanced infiltration caused by groundwater extraction is suspected to be both a prime factor in the disappearance of a lagoon system at the Toluca Basin and a potential risk to long-term groundwater quality. A combined approach of field investigation and numerical modeling was adopted to assess the groundwater-surface water interactions within the lagoon system. Potentiometric data indicate that current downward vertical hydraulic gradients below the lagoon and surrounding wetland area are extremely low suggesting very slow infiltration rates. Geochemical and isotope data from surface water and groundwater sampling also indicate that very little surface water infiltration has occurred. Numerical simulations demonstrate that enhanced surface water infiltration is unlikely to be the primary cause in the significant reduction in size of the lagoon system. Other factors such as modifications to the surface water drainage system and capture of spring flow from the surrounding mountainous regions are likely more significant. Simulations also suggest that contaminants originating in the lagoon system are currently entering nearby production wells although the total contaminant mass flux to the wells is still very low and significantly diluted.

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Resumen La Ciudad de México depende significativamente de los recursos de aguas subterráneas obtenidos del campo de pozos Sistema Lerma ubicado en la Cuenca Toluca, oeste de la Cuenca de México. Se sospecha que la infiltración estimulada causada por extracción intensiva de aguas subterráneas es un factor principal en la desaparición de un sistema de lagunas en la cabeceras del Río Lerma en el centro de México y un riesgo potencial para la calidad de aguas subterráneas a largo plazo en la región. Se adoptó un enfoque combinado de investigación de campo y modelizado numérico para evaluar las interacciones de agua superficial-agua subterránea dentro del sistema de lagunas. Datos potenciométricos indican que los gradientes hidráulicos verticales descendentes actuales, ubicados por debajo de la laguna y vecina área de humedales, son extremadamente bajos sugiriendo ritmos de infiltración muy lentos. Datos geoquímicos e isotópicos provenientes del muestreo de agua superficial y subterránea también indican que ha ocurrido muy poca infiltración de agua superficial. Las simulaciones numéricas demuestran cuantitativamente que no es probable que la infiltración estimulada de agua superficial sea la causa principal en la reducción significativa del tamaño del sistema de lagunas en la cabecera. Otros factores tal como modificaciones al sistema superficial de drenaje de agua y captura de flujo de manantial en las regiones montañosas vecinas son probablemente más significativos. Las simulaciones también sugieren que los contaminantes que se originan en el sistema de lagunas están actualmente ingresando a pozos de producción cercanos aunque el flujo de masa contaminante total a los pozos es aún muy bajo y diluido significativamente en los volúmenes grandes de extracción. La magnitud de la amenaza a largo plazo a la calidad del agua subterránea en los pozos de producción Sistema Lerma proveniente de contaminantes infiltrados es una preocupación y amerita estudios futuros.

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Résumé La Cité de Mexico dépend significativement des ressources en eau souterraine pompées au site de captages de Sistema Lerma, dans le Bassin de Toluca, à lOuest du Bassin de Mexico. Laugmentation de linfiltration, causée par lextraction extensive des eaux souterraines, est suspectée dêtre à la fois un facteur primaire de la disparition dun système de lagons en amont de la rivière Lerma au centre de Mexico, et un risque potentiel à long-terme pour la qualité de leau souterraine dans la région. Uen approche combinée détudes de terrain et de modélisation numérique a été adoptée pour estimer les interactions entre les eaux de surface et les eaux souterraines, au sein du système de lagons. Les données potentiométriques indiquent que les gradients hydrauliques verticaux descendants sont très bas au niveau des lagons, ce qui suppose un taux dinfiltration faible. Les données géochimiques et isotopiques provenant des eaux de surface et souterraines, indiquent également que peu deau de surface sinfiltrent. La simulation numérique démontre quantitativement que laugmentation de linfiltration des eaux de surface nest probablement pas la première cause de réduction des lagons. Dautres facteurs, tels que les modifications du drainage des eaux de surface, laménagement en captage des sources situées aux pieds des montagnes environnantes, sont probablement plus importants. Les simulations suggèrent également que les contaminants provenant des lagons se retrouvent également dans les captages les plus proches, bien que le flux total de contaminants entrant dans les captages reste faible. Les volumes dextraction étant très important ils diluent effectivement les contaminants. Les effets à long-terme de lextraction critique au niveau des forages de Sistema Lerma et de la dégradation de la qualité des eaux souterraines par les contaminants, nécessite une grande attention pour le futur.