Mediterranean hurricanes: large-scale environment and convective and precipitating areas from satellite microwave observations

Subsynoptic scale vortices that have been likened to tropical cyclones or polar lows (medicanes) are occasionally observed over the Mediterranean Sea. Generated over the sea, they are usually associated with strong winds and heavy precipitation and thus can be highly destructive in islands and costal areas. Only an accurate forecasting of such systems could mitigate these effects. However, at the moment, the predictability of these systems remains limited. <br><br> Due to the scarcity of conventional observations, use is made of NOAA/MetOp satellite observations, for which advantage can be taken of the time coverage differences between the platforms that carry it, to give a very complete temporal description of the disturbances. A combination of AMSU-B (Advanced Microwave Sounding Unit-B)/MHS (Microwave Humidity Sounder) observations permit to investigate precipitation associated with these systems while coincident AMSU-A (Advanced Microwave Sounding Unit-A) observations give insights into the larger synoptic-scale environment in which they occur. <br><br> Three different cases (in terms of intensity, location, trajectory, duration, and periods of the year – May, September and December, respectively) were investigated. Throughout these time periods, AMSU-A observations show that the persisting deep outflow of cold air over the sea together with an upper-level trough upstream constituted a favourable environment for the development of medicanes. AMSU-B/MHS based diagnostics show that convection and precipitation areas are large in the early stage of the low, but significantly reduced afterwards. Convection is maximum just after the upper-level trough, located upstream of cold mid-tropospheric air, reached its maximum intensity and acquired a cyclonic orientation

Hypoxia and fatigue impair rapid torque development of knee extensors in elite alpine skiers

This study examined the effects of acute hypoxia on maximal and explosive torque and fatigability in knee extensors of skiers. Twenty-two elite male alpine skiers performed 35 maximal, repeated isokinetic knee extensions at 180∘s-1 (total exercise duration 61.25 s) in normoxia (NOR, FiO2 0.21) and normobaric hypoxia (HYP, FiO2 0.13) in a randomized, single-blind design. Peak torque and rate of torque development (RTD) from 0 to 100 ms and associated Vastus Lateralis peak EMG activity and rate of EMG rise (RER) were determined for each contraction. Relative changes in deoxyhemoglobin concentration of the VL muscle were monitored by near-infrared spectroscopy. Peak torque and peak EMG activity did not differ between conditions and decreased similarly with fatigue (p < 0.001), with peak torque decreasing continuously but EMG activity decreasing significantly after 30 contractions only. Compared to NOR, RTD, and RER values were lower in HYP during the first 12 and 9 contractions, respectively (both p < 0.05). Deoxyhemoglobin concentration during the last five contractions was higher in HYP than NOR (p = 0.050) but the delta between maximal and minimal deoxyhemoglobin for each contraction was similar in HYP and NOR suggesting a similar muscle O2 utilization. Post-exercise heart rate (138 ± 24 bpm) and blood lactate concentration (5.8 ± 3.1 mmol.l-1) did not differ between conditions. Arterial oxygen saturation was significantly lower (84 ± 4 vs. 98 ± 1%, p < 0.001) and ratings of perceived exertion higher (6 ± 1 vs. 5 ± 1, p < 0.001) in HYP than NOR. In summary, hypoxia limits RTD via a decrease in neural drive in elite alpine skiers undertaking maximal repeated isokinetic knee extensions, but the effect of hypoxic exposure is negated as fatigue develops. Isokinetic testing protocols for elite alpine skiers should incorporate RTD and RER measurements as they display a higher sensitivity than peak torque and EMG activity

LONG LIFE FOR THE EASTERN MEDITERRANEAN MESOSCALE EDDIES

Abstract The three-dimensional structure of the eastern Mediterranean mesoscale eddies was studied using a combination of a high horizontal resolution numerical model (∼5 km) outputs, in-situ and satellite data. Most of these eddies show good similarity between model results and observations. The structure, formation, development and propagation of each feature were studied separately and the results were then compared. Westward propagation in the southern Ionian Sea and eastward propagation in the southern Levantine Basin were observed with lifetime of more than two years

Copernicus Cal/Val Solution - D3.2 - Recommendations for R&D on Cal/Val Methods

This document presents a gap analysis of the methods used in the calibration and validation of Earth Observation satellites relevant to the Copernicus programme and suggests recommendations for the research and developments required to fulfil this gap when/where possible. The document identifies the gaps and limitations of the CalVal methods, used for calibration and validation (CalVal) activities for the current Copernicus missions. It will also address the development needs for future Copernicus missions. Four types of missions are covered based on the division used in the rest of the CCVS project: optical, altimetry, radar and microwave and atmospheric composition. Finally, it will give a prioritized list of recommendations for R&D activities on the CalVal methods. The information included is mainly collected from the deliverables of work packages 1 and 2 in the CCVS project and from the consortium experts in CalVal activities

Regional and experiential differences in surgeon preference for the treatment of cervical facet injuries: a case study survey with the AO Spine Cervical Classification Validation Group

Purpose: The management of cervical facet dislocation injuries remains controversial. The main purpose of this investigation was to identify whether a surgeon’s geographic location or years in practice influences their preferred management of traumatic cervical facet dislocation injuries. Methods: A survey was sent to 272 AO Spine members across all geographic regions and with a variety of practice experience. The survey included clinical case scenarios of cervical facet dislocation injuries and asked responders to select preferences among various diagnostic and management options. Results: A total of 189 complete responses were received. Over 50% of responding surgeons in each region elected to initiate management of cervical facet dislocation injuries with an MRI, with 6 case exceptions. Overall, there was considerable agreement between American and European responders regarding management of these injuries, with only 3 cases exhibiting a significant difference. Additionally, results also exhibited considerable management agreement between those with ≤ 10 and &gt; 10&nbsp;years of practice experience, with only 2 case exceptions noted. Conclusion: More than half of responders, regardless of geographical location or practice experience, identified MRI as a screening imaging modality when managing cervical facet dislocation injuries, regardless of the status of the spinal cord and prior to any additional intervention. Additionally, a majority of surgeons would elect an anterior approach for the surgical management of these injuries. The study found overall agreement in management preferences of cervical facet dislocation injuries around the globe

Effect of surgical experience and spine subspecialty on the reliability of the {AO} Spine Upper Cervical Injury Classification System

OBJECTIVE The objective of this paper was to determine the interobserver reliability and intraobserver reproducibility of the AO Spine Upper Cervical Injury Classification System based on surgeon experience (&lt; 5 years, 5–10 years, 10–20 years, and &gt; 20 years) and surgical subspecialty (orthopedic spine surgery, neurosurgery, and "other" surgery). METHODS A total of 11,601 assessments of upper cervical spine injuries were evaluated based on the AO Spine Upper Cervical Injury Classification System. Reliability and reproducibility scores were obtained twice, with a 3-week time interval. Descriptive statistics were utilized to examine the percentage of accurately classified injuries, and Pearson’s chi-square or Fisher’s exact test was used to screen for potentially relevant differences between study participants. Kappa coefficients (κ) determined the interobserver reliability and intraobserver reproducibility. RESULTS The intraobserver reproducibility was substantial for surgeon experience level (&lt; 5 years: 0.74 vs 5–10 years: 0.69 vs 10–20 years: 0.69 vs &gt; 20 years: 0.70) and surgical subspecialty (orthopedic spine: 0.71 vs neurosurgery: 0.69 vs other: 0.68). Furthermore, the interobserver reliability was substantial for all surgical experience groups on assessment 1 (&lt; 5 years: 0.67 vs 5–10 years: 0.62 vs 10–20 years: 0.61 vs &gt; 20 years: 0.62), and only surgeons with &gt; 20 years of experience did not have substantial reliability on assessment 2 (&lt; 5 years: 0.62 vs 5–10 years: 0.61 vs 10–20 years: 0.61 vs &gt; 20 years: 0.59). Orthopedic spine surgeons and neurosurgeons had substantial intraobserver reproducibility on both assessment 1 (0.64 vs 0.63) and assessment 2 (0.62 vs 0.63), while other surgeons had moderate reliability on assessment 1 (0.43) and fair reliability on assessment 2 (0.36). CONCLUSIONS The international reliability and reproducibility scores for the AO Spine Upper Cervical Injury Classification System demonstrated substantial intraobserver reproducibility and interobserver reliability regardless of surgical experience and spine subspecialty. These results support the global application of this classification system

Patterns of precipitation and convection occurrence over the mediterranean basin derived from a decade of microwave satellite observations

International audienceThe Mediterranean region is characterized by its vulnerability to changes in the water cycle, with the impact of global warming on the water resources being one of the major concerns in social, economical and scientific ambits. Even if precipitation is the best-known term of the Mediterranean water budget, large uncertainties remain due to the lack of suitable offshore observational data. In this study, we use the data provided by the Advanced Microwave Sounding Unit-B (AMSU-B) on board NOAA satellites to detect and analyze precipitating and convective events over the last decade at spatial resolution of 0.2° latitude × 0.2° longitude. AMSU-B observation shows that rain occurrence is widespread over the Mediterranean in wintertime while reduced in the eastern part of the basin in summer. Both precipitation and convection occurrences display a weak diurnal cycle over sea. In addition, convection occurrences, which are essentially located over land during summertime, shift to mostly over the sea during autumn with maxima in the Ionian sub-basin and the Adriatic Sea. Precipitation occurrence is also inferred over the sea from two other widely used climatological datasets, HOAPS (Hamburg Ocean AtmosphereParameters and Fluxes from Satellite Data) and the European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis interim (ERA-Interim). There is generally a rather fair agreement between these climatologies for describing the large-scale patterns such as the strong latitudinal gradient of rain and eastward rain signal propagation. Furthermore, the higher spatial resolution of AMSU-B measurements (16 km at nadir) gives access to mesoscale details in the region (e.g., coastal areas). AMSU-B measurements show less rain occurrences than HOAPS during wintertime, thereby suggesting that some of the thresholds used in our method might be too stringent during this season. We also observed that convection occurrences in ERA-Interim are systematically lower than those derived from AMSU-B. These results are potentially valuable to evaluate the rainfall parameterization in weather and climate models and to constrain ocean models. © 2014 by the authors

A high resolution climatology of precipitation and deep convection over the Mediterranean region from operational satellite microwave data: development and application to the evaluation of model uncertainties

International audienceA new precipitation and convection dataset for the Mediterranean Basin, derived from operational satellite microwave data is documented. The dataset is derived from diagnostics that rely on brightness temperatures measured since 1999 in the water vapour absorption line (183-191 GHz). The dataset consists of twice-daily (a.m. and p.m.) and monthly maps of precipitation and convection occurrences on a 0.2° lat × 0.2° long grid for the area 25°-60° N, 10° W-50° E. The instruments used so far are the AMSU-B sensor on the NOAA-15 to -17 satellites, and the MHS sensor on the NOAA-18 and -19 and METOP-2 satellites, with precipitation and convection available separately for the different sensors. The slightly different radiometric characteristics of MHS compared to AMSU-B do not affect significantly the continuity of the dataset. Precipitation and convection data from different sensors on different satellites are remarkably consistent, with generally small biases between the instruments. When larger biases appear, they can be explained either by the drifts in the satellite orbit, scan asymmetry, or temporal aliasing from insufficiently resolving the diurnal cycle of precipitation and convection. After a description of climatological aspects of rain and deep convection occurrence, the interest of this dataset to evaluate model uncertainties for simulating a high-impact weather event and for climatic regional runs over this area is illustrated

Sentinel-2/MSI and LANDSAT8/OLI Radiometry Intercomparison Using RadCalNet Dataset and DIMITRI-toolbox

The Radiometric Calibration Network (RadCalNet) has been established by the Committee on Earth Observation Satellites (CEOS) Working Group on Calibration and Validation (WGCV) Infrared and Visible Optical Sensors Subgroup (IVOS) in 2013 and is open to public since July 2018. The RadCalNet consists of four international test sites providing automated in situ measurements and estimates of propagated top-of-atmosphere (TOA) reflectance (Bouvet et al. 2019). This work based on the work of Alhammoud et al. (2019) for the Sentinel-2/MSI validation; and on the work of Jing et al. (2019) to correct the directional effect. In this study we extend Alhammoud et al. (2019) analysis over RadCalNet up to 2021, instead of 2018. In addition, we will present the results of a cross-mission intercomparison over RadCalNet sites for MSI-A, MSI-B and OLI-8 using DIMITRI-Toolbox. The results confirm the viewing angle effect in the Sentinel-2 data at the RVUS and LCFR sites. The correction of the directional effect improves the results over the ratios of the individual orbits by up to 5% -10%, while the average ratios has been improved by barely about 1%. However the intercomparison results illustrate the relevance of RadCalNet dataset for the vicarious validation activity. Alhammoud et al. Sentinel-2 Level-1 Radiometry Assessment Using Vicarious Methods from DIMITRI Toolbox and Field Measurements From RadCalNet Database. IEEE JSTAR, 2019, Vol: 12(9) Bouvet et al. RadCalNet: A Radiometric Calibration Network for Earth Observing Imagers Operating in the Visible to Shortwave Infrared Spectral Range. Remote Sens. 2019, 11, 2401. https://doi.org/10.3390/rs11202401 Jing et al. Evaluation of RadCalNet Output Data Using Landsat 7, Landsat 8, Sentinel 2A, and Sentinel 2B Sensors. Remote Sens. 2019, 11, 541

In-Orbit Radiometric Performance of Sentinel-2/MSI: Inter-comparison with LANDSAT8/OLI-1 and LANDSAT9/OLI-2 Over Desert PICS using DIMITRI-toolbox

The Sentinel-2 constellation consists of two units MSI-A & MSI-B, which are Earth Observation (EO) optical missions developed and operated by the European Space Agency (ESA) in the framework of the Copernicus programme of the European Commission. The Copernicus Sentinel Optical Mission Performance Cluster (OPT-MPC) is responsible of the calibration, validation, and image quality of the user product. The inter-unit consistency of the radiometry measurements is critical for the mission as more Sentinel-2 platforms are planned in the future. In order to assess the validity and temporal stability of the radiometry measurements we use independent vicarious calibration methods for EO optical sensors, that are implemented in DIMITRI (Database for Imaging Multispectral Instruments and Tools for Radiometric Intercomparison) toolbox. The results of the validation show an excellent image quality and stable radiometric performance, which meets the mission requirements target. However, a small bias of 1.1% between the two sensors was observed in the VIS/NIR domain (see e.g. Alhammoud et al. 2021). Consequently, MSI-B measurements have been aligned with MSI-A by introducing a radiometric harmonisation factor on January 25th 2022 (PB04.00). Moreover, the OPT-MPC proposed to harmonize the sensors using MSI-A as reference for the new Collection 1 reprocessing campaign which is currently under preparation. This presentation provides a status of the Sentinel-2/MSI radiometric validation activities performed by the OPT-MPC. The results illustrate the expected improvement of the radiometric harmonisation between both units MSI-A & B. Furthermore, we present the results of cross-mission intercomparisons over desert PICS for MSI-A, MSI-B, OLI-1 and OLI- 2. The preliminary results show a good agreement between MSI/OLI to better than 2% while the OLI-1/OLI-2 agreement to better than 1% over VNIR bands. B. Alhammoud, C. Quang, V. Boccia and R. Q. Iannone, “Assessment of Copernicus Sentinel-2 Constellation After Five Years In-Orbit: Level-1C User-Products,” 2021 IEEE International Geoscience and Remote Sensing Symposium IGARSS, 2021, pp. 7759-7762, doi: 10.1109/IGARSS47720.2021.955485