Factors governing the deep ventilation of the Red Sea

Author Posting. © American Geophysical Union, 2015. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 120 (2015): 7493–7505, doi:10.1002/2015JC010996.A variety of data based on hydrographic measurements, satellite observations, reanalysis databases, and meteorological observations are used to explore the interannual variability and factors governing the deep water formation in the northern Red Sea. Historical and recent hydrographic data consistently indicate that the ventilation of the near-bottom layer in the Red Sea is a robust feature of the thermohaline circulation. Dense water capable to reach the bottom layers of the Red Sea can be regularly produced mostly inside the Gulfs of Aqaba and Suez. Occasionally, during colder than usual winters, deep water formation may also take place over coastal areas in the northernmost end of the open Red Sea just outside the Gulfs of Aqaba and Suez. However, the origin as well as the amount of deep waters exhibit considerable interannual variability depending not only on atmospheric forcing but also on the water circulation over the northern Red Sea. Analysis of several recent winters shows that the strength of the cyclonic gyre prevailing in the northernmost part of the basin can effectively influence the sea surface temperature (SST) and intensify or moderate the winter surface cooling. Upwelling associated with periods of persistent gyre circulation lowers the SST over the northernmost part of the Red Sea and can produce colder than normal winter SST even without extreme heat loss by the sea surface. In addition, the occasional persistence of the cyclonic gyre feeds the surface layers of the northern Red Sea with nutrients, considerably increasing the phytoplankton biomass.Saudi ARAMCO Marine Environmental Centre of King Abdullah University of Science and Technology (KAUST); Saudi Aramco Oil Co.2016-05-1

Propagation of tides in the Cochin estuarine system, southwest coast of India

14-24 Analysis of hourly data on sea level collected at four stations in the Cochin estuarine system has been made to understand the tidal and non-tidal sea level variations inside the estuary, for spring and neap phases during March 2000. Spring phase was dominated by semi-diurnal tides whereas neap phase was dominated by diurnal tides. Diurnal and semi-diurnal bands were together responsible for a high percentage of variance of the observed sea level. The dominance of shallow water tides was seen with increasing distance from the mouth. The sea level variance was dominated mainly by tidal signals, but the tidal influence decreased rapidly inside the estuary. Doodson’s Xo filter appears to be efficient for de-tiding the observed sea level time series. </smarttagtype

Currents in the Cochin estuarine system [southwest coast of India] during March 2000

123-132Analysis of current meter data collected in the Cochin estuarine system (southwest coast of India) has been made, to understand variations of currents in the estuary for spring and neap tidal phases during March 2000. The currents were strongest at an interior station as compared to stations close to the mouth of the estuary. The currents were also found to be rectilinear in nature at most of the stations. The observed currents were dominated by tidal signals - spring phase was dominated by semi-diurnal and neap phase by diurnal tidal currents

Surface wave statistics and spectra for Valiathura coastline, SW coast of India

9-17 A series of 12 monthly graphical three-dimensional plots were produced for Valiathura, SW coast of India, taking significant wave height, zero up-crossing period and direction as the three axes. Joint distributions of significant wave height and zero-up crossing period have also been developed for these months to understand the combination of these parameters in random waves. The fair weather period (November–April) was characterized by comparatively moderate wave activity with period ranging from 6 to 17.5 sec and direction of wave approach from 190° to 200°. During rough weather period (May – October), the waves exhibit a wider spread of direction ranging from 190° to 260° with periods ranging from 6 to 13.5 sec and significant wave height ranging from 0.6 to 3.2 m. Wave spectrum curves show that the TMA model gives better results and follows the observed spectra in a large number of cases during fair weather. During rough weather, TMA and Shadrin’s models show almost identical behavior. </smarttagtype

Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

Background Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications. Methods We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC). Findings In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683–0·717]). Interpretation In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required. Funding British Journal of Surgery Society