EPS-SG ICI Ice Water Path Product: ATBD

This algorithm theory basis document (ATBD) describes the operational retrievals of ice water path (IWP) that will be performed at EUMETSAT, based on data from the Ice Cloud Imager (ICI)

Backus-Gilbert footprint matching methodology applied on MWI and ICI observations

Final report of the EUMETSAT study with contract number EUM/CO/18/4600002075/CJA

Development of a cloud radiation database for EPS-SG ICI

This document is composed of technical reports written for each of the three tasks comprising the study Development of a cloud radiation database for EPS-SG ICI. The objective of the study was the development of a cloud radiation retrieval database to be used operationally by EUMETSAT upon launch of the Ice Cloud Imager (ICI). The database will be used within the retrieval algorithm to perform retrievals of cloud ice products, including ice water path (IWP)

Finding high-redshift dark stars with the James Webb Space Telescope

The first stars in the history of the Universe are likely to form in the dense central regions of 10^5-10^6 Msolar cold dark matter halos at z=10-50. The annihilation of dark matter particles in these environments may lead to the formation of so-called dark stars, which are predicted to be cooler, larger, more massive and potentially more long-lived than conventional population III stars. Here, we investigate the prospects of detecting high-redshift dark stars with the upcoming James Webb Space Telescope (JWST). We find that dark stars at z>6 are intrinsically too faint to be detected by JWST. However, by exploiting foreground galaxy clusters as gravitational telescopes, certain varieties of cool (Teff < 30000 K) dark stars should be within reach at redshifts up to z=10. If the lifetimes of dark stars are sufficiently long, many such objects may also congregate inside the first galaxies. We demonstrate that this could give rise to peculiar features in the integrated spectra of galaxies at high redshifts, provided that dark stars make up at least 1 percent of the total stellar mass in such objects.Comment: 12 pages, 7 figures; v2: matches published versio

Improvement of Odin/SMR water vapour and temperature measurements and validation of the obtained data sets

Its long photochemical lifetime makes H2O a good tracer for mesospheric dynamics. Temperature observations are also critical to study middle atmospheric dynamics. In this study, we present the reprocessing of 18 years of mesospheric H2O and temperature measurements from the Sub-Millimetre Radiometer (SMR) aboard the Odin satellite, resulting in a part of the SMR version 3.0 level 2 data set. The previous version of the data set showed poor accordance with measurements from other instruments, which suggested that the retrieved concentrations and temperature were subject to instrumental artefacts. Different hypotheses have been explored, and the idea of an underestimation of the singlesideband leakage turned out to be the most reasonable one. The value of the lowest transmission achievable has therefore been raised to account for greater sideband leakage, and new retrievals have been performed with the new settings. The retrieved profiles extend between 40-100 km altitude and cover the whole globe to reach 85\ub0 latitudes. A validation study has been carried out, revealing an overall better accordance with the compared instruments. In particular, relative differences in H2O mixing ratio are always in the \ub120% range between 40 and 70 km and diverge at higher altitudes, while temperature absolute differences are within \ub15K between 40-80 km and also diverge at higher altitudes

Tractable non-local correlation density functionals for flat surfaces and slabs

A systematic approach for the construction of a density functional for van der Waals interactions that also accounts for saturation effects is described, i.e. one that is applicable at short distances. A very efficient method to calculate the resulting expressions in the case of flat surfaces, a method leading to an order reduction in computational complexity, is presented. Results for the interaction of two parallel jellium slabs are shown to agree with those of a recent RPA calculation (J.F. Dobson and J. Wang, Phys. Rev. Lett. 82, 2123 1999). The method is easy to use; its input consists of the electron density of the system, and we show that it can be successfully approximated by the electron densities of the interacting fragments. Results for the surface correlation energy of jellium compare very well with those of other studies. The correlation-interaction energy between two parallel jellia is calculated for all separations d, and substantial saturation effects are predicted.Comment: 10 pages, 6 figure

Physicians' attitudes towards ePrescribing – evaluation of a Swedish full-scale implementation

<p>Abstract</p> <p>Background</p> <p>The penetration rate of Electronic Health Record (EHR) systems in health care is increasing. However, many different EHR-systems are used with varying ePrescription designs and functionalities. The aim of the present study was to evaluate experienced ePrescribers' attitudes towards ePrescribing for suggesting improvements.</p> <p>Methods</p> <p>Physicians (n = 431) from seven out of the 21 Swedish health care regions, using one of the six most widely implemented EHR-systems with integrated electronic prescribing modules, were recruited from primary care centers and hospital clinics of internal medicine, orthopaedics and surgery. The physicians received a web survey that comprised eight questions on background data and 19 items covering attitudes towards ePrescribing. Forty-two percent (n = 199) of the physicians answered the questionnaire; 90% (n = 180) of the respondents met the inclusion criteria and were included in the final analysis.</p> <p>Results</p> <p>A majority of the respondents regarded their EHR-system easy to use in general (81%), and for the prescribing of drugs (88%). Most respondents believed they were able to provide the patients better service by ePrescribing (92%), and regarded ePrescriptions to be time saving (91%) and to be safer (83%), compared to handwritten prescriptions. Some of the most frequently reported weaknesses were: not clearly displayed price of drugs (43%), complicated drug choice (21%), and the perception that it was possible to handle more than one patient at a time when ePrescribing (13%). Moreover, 62% reported a lack of receipt from the pharmacy after successful transmission of an ePrescription. Although a majority (73%) of the physicians reported that they were always or often checking the ePrescription a last time before transmitting, 25% declared that they were seldom or never doing a last check. The respondents suggested a number of improvements, among others, to simplify the drug choice and the cancellation of ePrescriptions.</p> <p>Conclusion</p> <p>The Swedish physicians in the group studied were generally satisfied with their specific EHR-system and with ePrescribing as such. However, identified weaknesses warrant improvements of the EHR-systems as well as of their implementation in the individual health care organisation.</p

Unified Treatment of Asymptotic van der Waals Forces

In a framework for long-range density-functional theory we present a unified full-field treatment of the asymptotic van der Waals interaction for atoms, molecules, surfaces, and other objects. The only input needed consists of the electron densities of the interacting fragments and the static polarizability or the static image plane, which can be easily evaluated in a ground-state density-functional calculation for each fragment. Results for separated atoms, molecules, and for atoms/molecules outside surfaces are in agreement with those of other, more elaborate, calculations.Comment: 6 pages, 5 figure

Satellite microwave measurements of cloud ice properties

Upper tropospheric cloud ice and water vapour are two intimately connected components of the atmosphere, that influence the Earth\u27s energy budget. The response of these components to a warming climate is not well understood. Global observations are crucial for improving our understanding of the time-varying climate, but the amount and quality of such observations of cloud ice and water vapour are limited. This thesis deals with satellite microwave measurements of cloud ice properties and humidity in several ways. The retrieval performance of a proposedpassive combined millimetre and sub-millimetre wave instrument for cloud ice observation is studied. Furthermore, retrievals of cloud ice mass and humidity from Odin-SMR (Odin-Sub-Millimetre Radiometer) are presented.Additionally, Odin-SMR retrieval products are combined with correlative datasets to study diurnal variations. It is confirmed that the proposed instrument would be well suited to observe ice cloud bulk properties, such as the vertically integrated mass content and an effective cloud particle size. A novel and general retrieval methodology is developed and applied to Odin-SMR measurements of thetropical upper troposphere. The retrieval algorithm recreates vertically resolved cloud ice mass and relative humidity with respect to ice (RHi) with a precision of 65% and 5 - 17 %RHi, respectively. The retrieval algorithmtakes into account of cloud inhomogeneities by a novel usage of radar data in order to reduce the systematic retrieval uncertainty. The retrieval products are shown to be in good agreement with correlative datasets fromthe CloudSat Cloud P rofiling Radar and Aura Microwave Limb Sounder. The diurnal cycle of water in the tropical upper troposphere is studied, by combining these datasets. Strong diurnal variations of cloud ice amount were observed primarily over land regions, with a pronounced maximum inthe afternoon. It was found that climate models have a problem of correctly simulating the observed short time-scale variations

Satellite microwave measurements of ice cloud properties

Ice clouds play an important role in Earth\u27s radiation balance and climate because they reflect incoming sunlight and trap outgoing infrared radiation. There is still an uncertainty about how ice clouds will respond to the effects of global warming. Many climate models use prognostic cloud mass schemes to represent cloud feedbacks. The problem is that there exist little observational data of cloud ice mass to validate this part of climate models. Microwave radiometry is a promising technique for cloud ice mass observations since the measured signal is more proportional to the cloud ice mass, compared to other conventional techniques. A first retrieval scheme and results of cloud ice mass observations from the first satellite instrument operating in the sub-mm part of the electromagnetic spectrum (Odin Sub-Millimetre Radiometer) are presented. A comparison to climate models show important differences in corresponding data. The retrieval of ice cloud properties in a Bayesian regression framework is the main focus of this study. This methodology has been studied with the aim to determine the retrieval performance of a suggested sub-mm instrument, dedicated to measure cloud ice properties. Bayesian regression methods require an a priori database of realistic cloud scenarios and corresponding simulated measurements, where relevant instrument characteristics are incorporated. Inversion of a measurement can be performed by interpolating between the cases in the database that approximately match the measurement or by applying a neural net to perform the mapping from measured data to cloud ice properties. The main achievement here is that a general method to combine prior information from different sources to generate retrieval databases has been developed