445 research outputs found

    CHEM2D-OPP: A new linearized gas-phase ozone photochemistry parameterization for high-altitude NWP and climate models

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    The new CHEM2D-Ozone Photochemistry Parameterization (CHEM2D-OPP) for high-altitude numerical weather prediction (NWP) systems and climate models specifies the net ozone photochemical tendency and its sensitivity to changes in ozone mixing ratio, temperature and overhead ozone column based on calculations from the CHEM2D interactive middle atmospheric photochemical transport model. We evaluate CHEM2D-OPP performance using both short-term (6-day) and long-term (1-year) stratospheric ozone simulations with the prototype high-altitude NOGAPS-ALPHA forecast model. An inter-comparison of NOGAPS-ALPHA 6-day ozone hindcasts for 7 February 2005 with ozone photochemistry parameterizations currently used in operational NWP systems shows that CHEM2D-OPP yields the best overall agreement with both individual Aura Microwave Limb Sounder ozone profile measurements and independent hemispheric (10°–90° N) ozone analysis fields. A 1-year free-running NOGAPS-ALPHA simulation using CHEM2D-OPP produces a realistic seasonal cycle in zonal mean ozone throughout the stratosphere. We find that the combination of a model cold temperature bias at high latitudes in winter and a warm bias in the CHEM2D-OPP temperature climatology can degrade the performance of the linearized ozone photochemistry parameterization over seasonal time scales despite the fact that the parameterized temperature dependence is weak in these regions

    Effects of model chemistry and data biases on stratospheric ozone assimilation

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    The innovations or observation minus forecast (O–F) residuals produced by a data assimilation system provide a convenient metric of evaluating global analyses. In this study, O–F statistics from the Global Ozone Assimilation Testing System (GOATS) are used to examine how ozone assimilation products and their associated O–F statistics depend on input data biases and ozone photochemistry parameterizations (OPP). All the GOATS results shown are based on a 6-h forecast and analysis cycle using observations from SBUV/2 (Solar Backscatter UltraViolet instrument-2) during September–October 2002. Results show that zonal mean ozone analyses are more independent of observation biases and drifts when using an OPP, while the mean ozone O–Fs are more sensitive to observation drifts when using an OPP. In addition, SD O–Fs (standard deviations) are reduced in the upper stratosphere when using an OPP due to a reduction of forecast model noise and to increased covariance between the forecast model and the observations. Experiments that changed the OPP reference state to match the observations by using an "adaptive" OPP scheme reduced the mean ozone O–Fs at the expense of zonal mean ozone analyses being more susceptible to data biases and drifts. Additional experiments showed that the upper boundary of the ozone DAS can affect the quality of the ozone analysis and therefore should be placed well above (at least a scale height) the region of interest

    Preliminary development and validation of a new endof-life patient-reported outcome measure assessing the ability of patients to finalise their affairs at the end of life

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    Introduction:The ability of patients to finalise their affairs at the end of life is an often neglected aspect of quality of life (QOL) measurement in palliative care effectiveness research despite compelling evidence of the high value patients place on this domain. Objective: This paper describes the preliminary development and evaluation of a new, single-item, end-of-life patientreported outcome measure (EOLPRO) designed to capture changes in the ability of patients to finalise their affairs at the end of life. Methods: Cognitive interviews with purposively sampled Australian palliative care patients (N = 9) were analysed thematically to explore content validity. Simultaneously, secondary analysis of data from a randomised controlled trial comparing ketamine and placebo for the management of cancer pain (N = 185) evaluated: construct validity; test-retest reliability; and responsiveness. Results:Preliminary findings suggest patients interpret the new measure consistently. The EOLPRO captures the ability to complete physical tasks and finalise practical matters although it is unclear whether emotional tasks or resolution of relationship issues are considered. Personal and financial affairs should be separated to allow for differences in ability for these two types of affairs. The significant correlation between performance status and EOLPRO scores (r = 0.41, p,<.01, n = 137) and expected relationships between EOLPRO and proximity to death and constipation demonstrated construct validity. Pre-and post-treatment EOLPRO scores moderately agreed (n = 14, k = 0.52 [95% CI 0.19, 0.84]) supporting reliability. The measure's apparent lack of sensitivity to discriminate between treatment responders and non-responders may be confounded. Conclusion:Based on the preliminary findings, the EOLPRO should be separated into 'personal' and 'financial' affairs with further testing suggested, particularly to verify coverage and responsiveness. Initial evaluation suggests that the single-item EOLPRO is a useful addition to QOL outcome measurement in palliative care effectiveness research because common palliative care specific QOL questionnaires do not include or explicitly capture this domain. © 2014 McCaffrey et al

    Double-blind, placebo-controlled, randomized trial of octreotide in malignant bowel obstruction

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    Context Does octreotide reduce vomiting in cancer-associated bowel obstruction? Objectives To evaluate the net effect of adding octreotide or placebo to standardized therapies on the number of days free of vomiting for populations presenting with vomiting and inoperable bowel obstruction secondary to cancer or its treatment. Methods Twelve services enrolled people with advanced cancer presenting with vomiting secondary to bowel obstruction where surgery or anti-cancer therapies were not indicated immediately. In a double-blind study, participants were randomized to placebo or octreotide (600 μg/24 hours by infusion). Both arms received standardized supportive therapy (infusion of ranitidine [200 mg/24 hours], dexamethasone [8 mg/24 hours], and parenteral hydration [10-20 mL/kg/24 hours]). The primary outcome was patient-reported days free of vomiting at 72 hours. Results In a study that recruited to the numbers identified in its power calculation, 87 participants provided data at 72 hours (45, octreotide arm). Seventeen people (octreotide) and 14 (placebo) were free of vomiting for 72 hours (P = 0.67). Mean days free of vomiting were 1.87 (SD 1.10; octreotide) and 1.69 (SD 1.15; placebo; P = 0.47). An adjusted multivariate regression of the incidence of vomiting over the study showed a reduced number of episodes of vomiting in the octreotide group (incidence rate ratio = 0.40; 95% CI: 0.19-0.86; P = 0.019); however, people in the octreotide arm were 2.02 times more likely to be administered hyoscine butylbromide (P = 0.004), potentially reflecting increased colicky pain. Conclusion Although there was no reduction in the number of days free of vomiting, the multivariate analysis suggests that further study of somatostatin analogues in this setting is warranted

    Novel alleles for combined drought and heat stress tolerance in wheat

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    Drought and heat waves commonly co-occur in many wheat-growing regions causing significant crop losses. The identification of stress associated quantitative trait loci, particularly those for yield, is problematic due to their association with plant phenology and the high genetic × environment interaction. Here we studied a panel of 315 diverse, spring type accessions of bread wheat (Triticum aestivum) in pots in a semi-controlled environment under combined drought and heat stress over 2 years. Importantly, we treated individual plants according to their flowering time. We found 134 out of the 145 identified loci for grain weight that were not associated with either plant phenology or plant height. The majority of loci uncovered here were novel, with favorable alleles widespread in Asian and African landraces providing opportunities for their incorporation into modern varieties through breeding. Using residual heterozygosity in lines from a nested association mapping population, we were able to rapidly develop near-isogenic lines for important target loci. One target locus on chromosome 6A contributed to higher grain weight, harvest index, thousand kernel weight, and grain number under drought and heat stress in field conditions consistent with allelic effects demonstrated in the genome-wide association study.Jessica Schmidt, Penny J. Tricker, Paul Eckermann, Priyanka Kalambettu, Melissa Garcia and Delphine Fleur

    Assimilation of stratospheric and mesospheric temperatures from MLS and SABER into a global NWP model

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    International audienceThe forecast model and three-dimensional variational data assimilation components of the Navy Operational Global Atmospheric Prediction System (NOGAPS) have each been extended into the upper stratosphere and mesosphere to form an Advanced Level Physics High Altitude (ALPHA) version of NOGAPS extending to ~100 km. This NOGAPS-ALPHA NWP prototype is used to assimilate stratospheric and mesospheric temperature data from the Microwave Limb Sounder (MLS) and the Sounding of the Atmosphere using Broadband Radiometry (SABER) instruments. A 60-day analysis period in January and February, 2006, was chosen that includes a well documented stratospheric sudden warming. SABER temperatures indicate that the SSW caused the polar winter stratopause at ~40 km to disappear, then reform at ~80 km altitude and slowly descend during February. The NOGAPS-ALPHA analysis reproduces this observed stratospheric and mesospheric temperature structure, as well as realistic evolution of zonal winds, residual velocities, and Eliassen-Palm fluxes that aid interpretation of the vertically deep circulation and eddy flux anomalies that developed in response to this wave-breaking event. The observation minus forecast (O-F) standard deviations for MLS and SABER are ~2 K in the mid-stratosphere and increase monotonically to about 6 K in the upper mesosphere. Increasing O-F standard deviations in the mesosphere are expected due to increasing instrument error and increasing geophysical variance at small spatial scales in the forecast model. In the mid/high latitude winter regions, 10-day forecast skill is improved throughout the upper stratosphere and mesosphere when the model is initialized using the high-altitude analysis based on assimilation of both SABER and MLS data

    Stratospheric Gravity Waves Excited by a Propagating Rossby Wave Train—A DEEPWAVE Case Study

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    There are only a few airborne observations of middle-atmospheric gravity waves in the Southern Hemisphere (Fritts et al. 2016; Rapp et al. 2021). Research flights to latitudes south of 608S are especially rare (e.g., Tuck et al. 1989; Parish and Bromwich 1989; Carli et al. 2000). These early airborne campaigns were mainly motivated by ozone research (Tuck et al. 1997; Tuck 2021) but also documented mesoscale temperature fluctuations (Gary 2008), gravity waves (Bacmeister et al. 1990), and turbulence (Tuck 2008). One of the more recent research flights was conducted during the Deep Propagating Gravity Wave Experiment (DEEPWAVE) experiment in July 2014 using the instrumented NSF/NCAR Gulfstream V research aircraft from an operating base in Christchurch, New Zealand (Fritts et al. 2016). The DEEPWAVE research flight 25 (RF25) went straight southwest from New Zealand to about 638S and returned along the same path back, see Fig. 1. The scientific objectives of this survey flight into the atmospheric flow above the Southern Ocean were based on operational forecasts by a suite of high resolution numerical weather prediction (NWP) models (Fritts et al. 2016, their Table 3) and were formulated as follows prior to the actual flight

    Report on the 1st SPARC Stratospheric Network for the Assessment of Predictability (SNAP). April 24-26 April 2013, Reading, UK

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    Stratospheric Network for the Assessment of Predictability (SNAP), 24-26 April 2013, Reading, UKThe first SPARC Stratospheric Network for the Assessment of Predictability (SPARC-SNAP) workshop was organized in the Department of Meteorology, University of Reading, UK, from 24 to 26 April 2013. This was a joint workshop with 3rd SPARC Dynamical Variability (SPARC-DynVar) (Manzini et al., this issue) workshop 22-24 April with the 24th April as a joint day. The joint workshop was well attended and had around 100 participants (http://www.met.reading.ac.uk/~pn904784/DynVar_SNAP_Workshop/participant.html) from 16 countries in Europe, Asia, Africa, Australia, North America, and South America (Participants figure). In the SNAP part of workshop (including the joint day) there were two keynote address, nine invited talks, six contributory talks and 24 posters.The authors are grateful to the Natural Environment Research Council and WCRP-SPARC for their financial support
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