An analysis of the vertical structure equation for arbitrary thermal profiles

The vertical structure equation is a singular Sturm-Liouville problem whose eigenfunctions describe the vertical dependence of the normal modes of the primitive equations linearized about a given thermal profile. The eigenvalues give the equivalent depths of the modes. The spectrum of the vertical structure equation and the appropriateness of various upper boundary conditions, both for arbitrary thermal profiles were studied. The results depend critically upon whether or not the thermal profile is such that the basic state atmosphere is bounded. In the case of a bounded atmosphere it is shown that the spectrum is always totally discrete, regardless of details of the thermal profile. For the barotropic equivalent depth, which corresponds to the lowest eigen value, upper and lower bounds which depend only on the surface temperature and the atmosphere height were obtained. All eigenfunctions are bounded, but always have unbounded first derivatives. It was proved that the commonly invoked upper boundary condition that vertical velocity must vanish as pressure tends to zero, as well as a number of alternative conditions, is well posed. It was concluded that the vertical structure equation always has a totally discrete spectrum under the assumptions implicit in the primitive equations

On the Reprocessing and Reanalysis of Observations for Climate

The long observational record is critical to our understanding of the Earth s climate, but most observing systems were not developed with a climate objective in mind. As a result, tremendous efforts have gone into assessing and reprocessing the data records to improve their usefulness in climate studies. Many challenges remain, such as tracking the improvement of processing algorithms and limited spatial coverage. Reanalyses have fostered significant research, yet reliable global trends in many physical fields are not yet attainable, despite significant advances in data assimilation and numerical modeling. Communication of the strengths, limitations and uncertainties of reprocessed observations and reanalysis data, not only among the community of developers, but also with the extended research community, including the new generations of researchers and the decision makers is crucial for further advancement of the observational data records. WCRP provides the means to bridge the different motivating objectives on which national efforts focus

A Multivariate Treatment of Bias for Sequential Data Assimilation: Application to the Tropical Oceans

International audienceThis paper discusses the problems arising from the presence of system bias in ocean data assimilation taking examples from the ECMWF ocean reanalysis used for seasonal forecasting. The examples illustrate how in a biased system, the non-stationary nature of the observing system is a handicap for the reliable representation of climate variability. It is also shown how the bias can be aggravated by the assimilation process, as is the case for the temperature bias in the eastern equatorial Pacific, linked to a spurious vertical circulation generated by the data assimilation. A generalized algorithm for treatment of bias in sequential data assimilation has been implemented. The scheme allows the control variables of the bias to be different from those for the state vector. Experiments were conducted to evaluate the sensitivity of the results to the choice of bias variables. Results highlight the importance of the correct choice of variables for the bias: while correcting the bias in the pressure field reduces the bias in temperature and in the velocity field, the direct correction of the bias in the temperature field reduces the temperature bias, but significantly increases the error in the velocity field. Analysis of the error statistics reveals that the bias term is not constant in time, but exhibits large interannual fluctuations. The bias algorithm has been generalized further to include temporal variations of the bias term. A memory factor is included to allow for the slow variations of the bias, and a prescribed bias term is added to represent errors known a-priori. Several experiments have been conducted to illustrate the sensitivity of the results to the time evolution of the bias

Ten priority science gaps in assessing climate data record quality

Decision makers need accessible robust evidence to introduce new policies in an effort to mitigate and adapt to climate change. There is an increasing amount of environmental information available to policy makers concerning observations and trends relating to the climate. However, this data is hosted across a multitude of websites often with inconsistent metadata and sparse information relating to the quality, accuracy and validity of the data. Subsequently, the task of comparing datasets to decide which is the most appropriate for a certain purpose is very complex and often infeasible. In support of the European Union’s Copernicus Climate Change Service (C3S) mission to provide authoritative information about the past, present and future climate in Europe and the rest of the world, each dataset to be provided through this service must undergo an evaluation of its climate relevance and scientific quality to help with data comparisons. This paper presents the framework for Evaluation and Quality Control (EQC) of climate data products derived from satellite and in situ observations to be catalogued within the C3S Climate Data Store (CDS). The EQC framework will be implemented by C3S as part of their operational quality assurance programme. It builds on past and present international investment in Quality Assurance for Earth Observation initiatives, extensive user requirements gathering exercises, as well as a broad evaluation of over 250 data products and a more in-depth evaluation of a selection of 24 individual data products derived from satellite and in situ observations across the land, ocean and atmosphere Essential Climate Variable (ECV) domains. A prototype Content Management System (CMS) to facilitate the process of collating, evaluating and presenting the quality aspects and status of each data product to data users is also described. The development of the EQC framework has highlighted cross-domain as well as ECV specific science knowledge gaps in relation to addressing the quality of climate data sets derived from satellite and in situ observations. We discuss 10 common priority science knowledge gaps that will require further research investment to ensure all quality aspects of climate data sets can be ascertained and provide users with the range of information necessary to confidently select relevant products for their specific application

Atmospheric Reanalyses-Recent Progress and Prospects for the Future. A Report from a Technical Workshop, April 2010

In April 2010, developers representing each of the major reanalysis centers met at Goddard Space Flight Center to discuss technical issues - system advances and lessons learned - associated with recent and ongoing atmospheric reanalyses and plans for the future. The meeting included overviews of each center s development efforts, a discussion of the issues in observations, models and data assimilation, and, finally, identification of priorities for future directions and potential areas of collaboration. This report summarizes the deliberations and recommendations from the meeting as well as some advances since the workshop

Advancing global & regional reanalyses

This report outlines the structure of and summarizes the recommendations made at the 5th International Conference on Reanalysis (ICR5), attended by 259 participants from 37 countries, in Rome (Italy), on 13-17 November 2017. It first summarizes the conference structure. Then, the key recommendations of ICR5 are given for the five main conference topics: production; observations (data rescue and preparation); data assimilation methods; quality assurance of reanalysis; and applications in science, services, and policymaking. Lastly, five high-level recommendations are proposed to managing agencies on how best to advance the field of reanalyses, which serves tens of thousands of users, via enhanced research, development, and operations

CO2: An operational anthropogenic CO2 emissions monitoring & verification support capacity

This is the third report form the CO2 Monitoring Task Force on the multiple input streams of in-situ observations that are requirement for the Copernicus CO2 Monitoring and Verification Support capacity to: (i) calibrated and validate the space component, (ii) assimilate data in the models and integrate information in the core of the system, and (iii) evaluate the output generated by the system for its end users. The availability of sustained in situ networks is currently a significant factor of risk that needs to be mitigated to establish a European CO 2 support capacity which is fit-for-purpose. The current status of existing networks may be the source of large uncertainties in anthropogenic CO2 emission estimates as well as limited capability in meeting the requirements for country, large city and point source scale assessments. This conclusion results from a risk analysis formulated for four scenarios: 1) maintaining the status quo, 2) assuring sustained funding for the status quo, 3) enhancing network capabilities at European scale with sustained funding and 4) with a significantly improved in situ infrastructure in Europe and beyond. This report substantiates the multifaceted needs and requirements of the European CO2 support capacity with respect to in situ observations. The analysis concerns all core elements of the envisaged integrated system with a particular attention on the impact of such observations in achieving the proposed objectives. The specific needs for the validation of products delivered by the space component that is, the Copernicus Sentinels CO2 monitoring constellation, are addressed as another prerequisite for the success of the CO2 support capacity. This European asset will represent a significant contribution to the virtual constellation proposed by the Committee on Earth Observation Satellites (CEOS) and, accordingly, complementary requirements are elaborated in that international frame. The report highlights that although high measurement standards are present within existing networks such as ICOS, in the context of the needs for targeted in situ data for the realization of the operational system, these data are not fully fit-for-purpose. A fundamental prerequisite is to have a good geographical coverage over Europe for evaluating the data assimilation and modeling system over a large variety of environmental conditions such as, for instance, urban areas, agricultural regions, forested zones and industrial complexes. The in situ observations need to be extended under a coordinated European lead with sustained infrastructure and targeted additional and maintained long-term funding. It has been clearly understood from the onset that the international dimension of the European CO2 support capacity would be critical and that these aspects should be developed in parallel to, and in synergy with the definition and implementation of a European contributing system. It was also understood that this international dimension had both strategic, policy relevant and technical dimensions and the Commission and the relevant European institutional partners have started since several years to engage both bilaterally and multilaterally with the relevant stakeholders and counterparts to develop these relations. Specifically, CEOS will undertake, over the next few years, dedicated preparatory work in a coordinated international context, to provide cumulative added value to the specific programmatic activities of their member agencies. Concerted efforts have already begun in the context of the European Commission's Chairmanship of CEOS in 2018. It is recognized in the context of the European efforts, and increasingly by our international counterparts that a broad and holistic system approach is required to address the requirements which are represented by the climate policy, of which the satellite component, whilst important, cannot effectively be developed in isolation. This system indeed includes the satellite observing capability but in addition, the required modelling component and data integration elements, prior information, ancillary data and in situ observations delivered by essential networks. Acknowledging the need for an efficient coordination at international level for instance via the Global Atmosphere Watch programme of the World Meteorological Organisation is a key towards a successful implementation of appropriate actions to ensure the sustainability of essential networks, to enhance current network capabilities with new observations and to propose adequate governance schemes. Such actions to mitigate current network limitations are deemed critical to implementing the Copernicus CO 2 Monitoring & Verification Support capacity in its full strength.JRC.D.6-Knowledge for Sustainable Development and Food Securit

Acceptance and commitment therapy for people living with motor neuron disease: an uncontrolled feasibility study

Background Motor neuron disease (MND) is a fatal, progressive neurodegenerative disease that causes progressive weakening and wasting of limb, bulbar, thoracic and abdominal muscles. Clear evidence-based guidance on how psychological distress should be managed in people living with MND (plwMND) is lacking. Acceptance and Commitment Therapy (ACT) is a form of psychological therapy that may be particularly suitable for this population. However, to the authors' knowledge, no study to date has evaluated ACT for plwMND. Consequently, the primary aim of this uncontrolled feasibility study was to examine the feasibility and acceptability of ACT for improving the psychological health of plwMND. Methods PlwMND aged ≥ 18 years were recruited from 10 UK MND Care Centres/Clinics. Participants received up to 8 one-to-one ACT sessions, developed specifically for plwMND, plus usual care. Co-primary feasibility and acceptability outcomes were uptake (≥ 80% of the target sample [N = 28] recruited) and initial engagement with the intervention (≥ 70% completing ≥ 2 sessions). Secondary outcomes included measures of quality of life, anxiety, depression, disease-related functioning, health status and psychological flexibility in plwMND and quality of life and burden in caregivers. Outcomes were assessed at baseline and 6 months. Results Both a priori indicators of success were met: 29 plwMND (104%) were recruited and 76% (22/29) attended ≥ 2 sessions. Attrition at 6-months was higher than anticipated (8/29, 28%), but only two dropouts were due to lack of acceptability of the intervention. Acceptability was further supported by good satisfaction with therapy and session attendance. Data were possibly suggestive of small improvements in anxiety and psychological quality of life from baseline to 6 months in plwMND, despite a small but expected deterioration in disease-related functioning and health status. Conclusions There was good evidence of acceptability and feasibility. Limitations included the lack of a control group and small sample size, which complicate interpretation of findings. A fully powered RCT to evaluate the clinical and cost-effectiveness of ACT for plwMND is underway