scholarly journals A decadal cirrus clouds climatology from ground-based and spaceborne lidars above the south of France (43.9° N–5.7° E)

2013 ◽  
Vol 13 (14) ◽  
pp. 6951-6963 ◽  
Author(s):  
C. Hoareau ◽  
P. Keckhut ◽  
V. Noel ◽  
H. Chepfer ◽  
J.-L. Baray
Keyword(s):  
Observation Time ◽  
Cirrus Clouds ◽  
Cirrus Cloud ◽  
Upper Troposphere ◽  
Cloud Parameters ◽  
Cloud Properties ◽  
Total Observation Time ◽  
The Mean ◽  
Ground Based Lidar ◽  
Total Observation

Abstract. This study provides an analysis of cirrus cloud properties at midlatitude in the southern part of France from ground-based and spaceborne lidars. A climatology of cirrus cloud properties and their evolution over more than 12 yr is presented and compared to other mid-latitude climatological studies. Cirrus clouds occur ~37% of the total observation time and remain quasi-constant across seasons with a variation within ~5% around the mean occurrence. Similar results are obtained from CALIOP and the ground-based lidar, with a mean difference in occurrence of ~5% between both instruments. From the ground-based lidar data, a slight decrease in occurrence of ~3% per decade is observed but found statistically insignificant. Based on a clustering analysis of cirrus cloud parameters, three distinct classes have been identified and investigations concerning their origin are discussed. Properties of these different classes are analysed, showing that thin cirrus in the upper troposphere represent ~50% of cloud cover detected in summer and fall, decreasing by 15–20% for other seasons.

scholarly journals A decadal cirrus clouds climatology from ground-based and spaceborne lidars above south of France (43.9° N–5.7° E)

2013 ◽  
Vol 13 (3) ◽  
pp. 6379-6417 ◽  
Author(s):  
C. Hoareau ◽  
P. Keckhut ◽  
V. Noel ◽  
H. Chepfer ◽  
J.-L. Baray
Keyword(s):  
Clustering Analysis ◽  
Observation Time ◽  
Cirrus Clouds ◽  
Cirrus Cloud ◽  
Upper Troposphere ◽  
Cloud Parameters ◽  
Total Observation Time ◽  
The Mean ◽  
Ground Based Lidar ◽  
Total Observation

Abstract. This study provides an analysis of cirrus clouds properties at midlatitude in the southern part of France from ground-based and spaceborne lidars. A climatology of cirrus clouds properties and their evolution over more than 12 yr is presented and compared to other mid-latitude climatological studies. Cirrus clouds occur ~ 37% of the total observation time and remain quasi-constant across seasons with a variation within ~ 5% around the mean occurrence. Similar results are obtained from CALIOP and the ground-based lidar, with a mean difference in occurrence of ~ 5% between both instruments. From the ground-based lidar data, a slight decrease in occurrence of ~ 3% per decade is observed but found statistically insignificant. Based on a clustering analysis of cirrus cloud parameters, three distinct classes have been identified and investigations concerning their origin are discussed. Properties of these different classes are analysed, showing that thin cirrus in the upper troposphere represent ~ 50% of cloud cover detected in summer and fall, decreasing by 15–20% for other seasons.

Stability in Waking-Sleep States in Neonates as a Predictor of Long-Term Neurologic Outcome

PEDIATRICS ◽  
1985 ◽  
Vol 76 (1) ◽  
pp. 52-63
Author(s):  
Cesare T. Lombroso ◽  
Yoichi Matsumiya
Keyword(s):  
Statistical Significance ◽  
Observation Time ◽  
Long Term Outcomes ◽  
Newborn Period ◽  
Waking And Sleep ◽  
Total Observation Time ◽  
Total Observation ◽  
The Individual

Thirty-three full-term neonates were ranked blindly on a scale ranging from the least to the highest "risk" for future neurologic complications on the basis of available perinatal biographies, tests, and examinations performed during the newborn period. Four prolonged polygraphic-behavioral recordings were obtained one week apart beginning at ten days after birth. Five waking and sleep states were scored in each session as percentages of total observation time, giving a total of 20 scores for each baby to be subjected to analysis of variance. These measures also provided individual profile consistency or variability in maintaining waking-sleep states over the selected period of postnatal time. The whole cohort, except three infants who could not be followed adequately, was then reexamined periodically over a period ranging from 3 to 4 years (±6 months) for neurologic and developmental assessments. Except for two scores that produced a low level of statistical significance (P < .05), the other 18 scores were found to be not associated with long-term outcomes. Even the first two scores were not satisfactory discriminators for the outcome of the individual babies. However, when coefficients of concordance (W) were computed from each individual baby profile, significant statistics (P < .001) emerged to indicate good correlations between high or low W values in the newborn period and long-term outcomes. All 17 newborns who had W scores greater than 0.9 were found to be normal at follow-up regardless of the poor ranking given several of them during the newborn period. Among the 13 newborns who had W scores less than 0.9, 11 had a poor clinical outcome at follow-up, though several had been ranked initially as falling within the least "risk" group.

scholarly journals Balloon-borne match measurements of midlatitude cirrus clouds

2014 ◽  
Vol 14 (14) ◽  
pp. 7341-7365 ◽  
Author(s):  
A. Cirisan ◽  
B. P. Luo ◽  
I. Engel ◽  
F. G. Wienhold ◽  
M. Sprenger ◽  
...  
Keyword(s):  
Temperature Fluctuations ◽  
Cloud Microphysics ◽  
Cirrus Clouds ◽  
Climate Feedback ◽  
Small Scale ◽  
Model Parameters ◽  
Cirrus Cloud ◽  
Air Mass ◽  
Upper Troposphere ◽  
Weather Model

Abstract. Observations of high supersaturations with respect to ice inside cirrus clouds with high ice water content (> 0.01 g kg−1) and high crystal number densities (> 1 cm−3) are challenging our understanding of cloud microphysics and of climate feedback processes in the upper troposphere. However, single measurements of a cloudy air mass provide only a snapshot from which the persistence of ice supersaturation cannot be judged. We introduce here the "cirrus match technique" to obtain information about the evolution of clouds and their saturation ratio. The aim of these coordinated balloon soundings is to analyze the same air mass twice. To this end the standard radiosonde equipment is complemented by a frost point hygrometer, "SnowWhite", and a particle backscatter detector, "COBALD" (Compact Optical Backscatter AerosoL Detector). Extensive trajectory calculations based on regional weather model COSMO (Consortium for Small-Scale Modeling) forecasts are performed for flight planning, and COSMO analyses are used as a basis for comprehensive microphysical box modeling (with grid scale of 2 and 7 km, respectively). Here we present the results of matching a cirrus cloud to within 2–15 km, realized on 8 June 2010 over Payerne, Switzerland, and a location 120 km downstream close to Zurich. A thick cirrus cloud was detected over both measurement sites. We show that in order to quantitatively reproduce the measured particle backscatter ratios, the small-scale temperature fluctuations not resolved by COSMO must be superimposed on the trajectories. The stochastic nature of the fluctuations is captured by ensemble calculations. Possibilities for further improvements in the agreement with the measured backscatter data are investigated by assuming a very slow mass accommodation of water on ice, the presence of heterogeneous ice nuclei, or a wide span of (spheroidal) particle shapes. However, the resulting improvements from these microphysical refinements are moderate and comparable in magnitude with changes caused by assuming different regimes of temperature fluctuations for clear-sky or cloudy-sky conditions, highlighting the importance of proper treatment of subscale fluctuations. The model yields good agreement with the measured backscatter over both sites and reproduces the measured saturation ratios with respect to ice over Payerne. Conversely, the 30% in-cloud supersaturation measured in a massive 4 km thick cloud layer over Zurich cannot be reproduced, irrespective of the choice of meteorological or microphysical model parameters. The measured supersaturation can only be explained by either resorting to an unknown physical process, which prevents the ice particles from consuming the excess humidity, or – much more likely – by a measurement error, such as a contamination of the sensor housing of the SnowWhite hygrometer by a precipitation drop from a mixed-phase cloud just below the cirrus layer or from some very slight rain in the boundary layer. This uncertainty calls for in-flight checks or calibrations of hygrometers under the special humidity conditions in the upper troposphere.

scholarly journals The roles of dynamical variability and aerosols in cirrus cloud formation

2003 ◽  
Vol 3 (2) ◽  
pp. 1415-1451 ◽  
Author(s):  
B. Kärcher ◽  
J. Ström
Keyword(s):  
Probability Distributions ◽  
Cirrus Clouds ◽  
Cloud Formation ◽  
Cirrus Cloud ◽  
Ice Crystal ◽  
Mesoscale Variability ◽  
Aerosol Composition ◽  
Airborne Measurements ◽  
Cloud Properties

Abstract. The probability of occurrence of ice crystal number densities in young cirrus clouds is examined based on airborne measurements. The observations have been carried out at midlatitudes in both hemispheres at equivalent latitudes (~52–55° N/S) during the same season (local autumn in 2000). The in situ measurements considered in the present study include temperatures, vertical velocities, and ice crystal concentrations, the latter determined with high precision and accuracy using a counterflow virtual impactor. Most young cirrus clouds typically contain high number densities (1–10 cm−3) of small (diameter <20 μm) ice crystals. This mode dominates the probability distributions in both hemispheres and is shown to be caused by rapid cooling rates associated with updraft speeds in the range 10–100 cm s-1. A second mode containing larger crystals extends from ~1 cm−3 to low concentrations close to the detection threshold (~3×104cm−3) and is associated with lower updraft speeds. Results of a statistical analysis provide compelling evidence that the dynamical variability of vertical air motions on the mesoscale is the key factor determining the observed probability distributions of pristine ice crystal concentrations in cirrus. Other factors considered are variations of temperature as well as size, number, and ice nucleation thresholds of the freezing aerosol particles. The variability in vertical velocities is likely caused by atmospheric waves. Inasmuch as gravity waves are widespread, mesoscale variability in vertical velocities can be viewed as a universa  feature of young cirrus clouds. Large-scale models that do not account for this subgrid-scale variability yield erroneous predictions of the variability of basic cirrus cloud properties. Climate change may bring about changes in the global distribution of updraft speeds, mean air temperatures, and aerosol properties. As shown in this work, these changes could significantly modify the probability distribution of cirrus ice crystal concentrations. This study emphasizes the key role of vertical velocities and mesoscale variability in vertical velocities in controlling cirrus properties. The results suggest that, in any effort to ascribe cause to trends of cirrus cloud properties, a careful evaluation of dynamical changes in cloud formation should be done before conclusions regarding the role of other anthropogenic factors, such as changes in aerosol composition, are made.

Dynamic Processes in Cirrus Clouds: Concepts and Models

Cirrus ◽  
2002 ◽  
Author(s):  
David O’C. Starr ◽  
Markus Quante
Keyword(s):  
Cirrus Clouds ◽  
Radiative Properties ◽  
Cirrus Cloud ◽  
Early Model ◽  
Minimum Requirement ◽  
Microphysical Properties ◽  
Cloud Properties ◽  
Cloud Models ◽  
New Concepts

Advancement in the understanding of cirrus clouds and their life cycle comes through symbiotic use of models, observations, and related concepts (fig. 18.1). Models of cirrus clouds represent an integration of our knowledge of cirrus cloud properties and processes. They provide a capacity to extend knowledge and enhance understanding in ways that complement existing observational capabilities. Models can be used to develop new theories, such as parameterizations, and focus science issues and observational requirements and developments. For example, early model results of Starr and Cox (1985a) and Starr (1987b) predicted that fine cellular structure (~lkm or less) would be found in the upper part of extended stratiform cirrus clouds. This prediction was confirmed when high-frequency sensors were deployed both for active remote sensing (Sassen et al. 1990a, 1995) and later for in-situ measurements (Quante and Brown 1992; Gultepe et al. 1995; Quante et al. 1996). Sampling rates of 10Hz, or better, are now accepted as a minimum requirement for resolving cirrus cloud internal structure and circulation where 1-Hz or coarser measurements were previously used. Similarly, discrepancies between observed cloud radiative properties and calculations (theory) based on corresponding in-situ observations of cloud microphysical properties (Sassen et al. 1990b) led to the development of improved observing capabilities for small ice crystals (Arnott et al. 1994; Miloshevich and Heymsfield 1997; Lawson et al. 1998). Such sensors are now regarded as part of the standard complement when doing in-situ microphysical measurements in cirrus. At the same time, observations are absolutely essential in developing and evaluating cloud models. No cloud modeler wants to apply a model or theory too far beyond the limits of what can be observationally confirmed, at least in gross terms. The third aspect of this triad is concepts. Although models and observations can lead to predictions or diagnosis of unexpected relationships, they are each limited by the concepts that were used in their design and/or implementation. In the end, new concepts arising from analogy to other phenomena and/or from synergistic integration of existing knowledge can lead to new understanding, new models, new instruments, and new sampling strategies (fig. 18.1). Chapter 17 focuses on observations of internal cloud circulation and structure.

scholarly journals Recurrence of Cholesteatoma - A Retrospective Study Including 1,006 Patients for More than 33 Years

2019 ◽  
Vol 24 (01) ◽  
pp. e18-e23 ◽  
Author(s):  
Patrick Rønde Møller ◽  
Christina Nygaard Pedersen ◽  
Line R. Grosfjeld ◽  
Christian E. Faber ◽  
Bjarki D. Djurhuus
Keyword(s):  
Middle Ear ◽  
Total Sample ◽  
Observation Time ◽  
Benign Tumors ◽  
Retraction Pocket ◽  
Risk Of Recurrence ◽  
Middle Ear Cholesteatoma ◽  
Total Observation Time ◽  
Total Observation ◽  
First Time

Abstract Introduction Cholesteatomas are benign tumors consisting of skin, and growing inside a retraction pocket in the tympanic membrane. Cholesteatomas can occupy the entirety of the middle ear, and are known for their osteolytic capabilities. Surgery is the only curative treatment for cholesteatomas. Objective To describe the risk of recurrence after first-time surgically-treated middle-ear cholesteatoma (STMEC1) on the island of Funen from 1983 to 2015. Methods Cases of STMEC1 were identified in the Danish National Hospital Register. The medical records were reviewed. Time-to-event analyses were applied. The ears were followed from STMEC1 to a secondary cholesteatoma, emigration, death, or end of follow-up. Results Records from 1,006 patients with STMEC1 were reviewed. A total of 54 patients were submitted to surgery on both ears. The total sample consisted of 1,060 ears with STMEC1; 300 were children's (< 16 years) ears, and 760 were adult's ears. The total observation time was of 12,049 years.The overall estimated proportion with recurrence 5 years after surgery was of 37% in children and of 15% in adults. The older the child was at the first surgery, the risk decreased by 7% per year. In children, canal wall up (CWU) mastoidectomy without obliteration was associated with a hazard ratio for recurrence of 1.9 (95% confidence interval [95%CI]: 1.2–3.0) compared with CWU with obliteration. Conclusion Compared with adults, children were had 2.6 times more risk of recurrence. Procedures performed without mastoidectomy had the lowest risk of recurrence. In children, obliteration was associated with a significantly lower risk of recurrence. However, patients were not randomized regarding the surgical approach; thus, the association between approach and risk of recurrence was likely influenced by confounding factors.

scholarly journals Long-term trend analysis and climatology of tropical cirrus clouds using 16 years of lidar data set over Southern India

2015 ◽  
Vol 15 (24) ◽  
pp. 13833-13848 ◽  
Author(s):  
A. K. Pandit ◽  
H. S. Gadhavi ◽  
M. Venkat Ratnam ◽  
K. Raghunath ◽  
S. V. B. Rao ◽  
...  
Keyword(s):  
Optical Thickness ◽  
Radiative Forcing ◽  
Climate Model ◽  
Cirrus Clouds ◽  
Orthogonal Polarization ◽  
Cirrus Cloud ◽  
Data Set ◽  
Tropical Tropopause ◽  
Recent Climate ◽  
Ground Based Lidar

Abstract. Sixteen-year (1998–2013) climatology of cirrus clouds and their macrophysical (base height, top height and geometrical thickness) and optical properties (cloud optical thickness) observed using a ground-based lidar over Gadanki (13.5° N, 79.2° E), India, is presented. The climatology obtained from the ground-based lidar is compared with the climatology obtained from 7 and a half years (June 2006–December 2013) of Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) observations. A very good agreement is found between the two climatologies in spite of their opposite viewing geometries and the differences in sampling frequencies. Nearly 50–55 % of cirrus clouds were found to possess geometrical thickness less than 2 km. Ground-based lidar is found to detect a higher number of sub-visible clouds than CALIOP which has implications for global warming studies as sub-visible cirrus clouds have significant positive radiative forcing. Cirrus clouds with mid-cloud temperatures between −50 to −70 °C have a mean geometrical thickness greater than 2 km in contrast to the earlier reported value of 1.7 km. Trend analyses reveal a statistically significant increase in the altitude of sub-visible cirrus clouds which is consistent with the recent climate model simulations. The mid-cloud altitude of sub-visible cirrus clouds is found to be increasing at the rate of 41 ± 21 m year−1. Statistically significant decrease in optical thickness of sub-visible and thick cirrus clouds is observed. Also, the fraction of sub-visible cirrus cloud is found to have increased by 9 % in the last 16 years (1998 to 2013). This increase is mainly compensated by a 7 % decrease in thin cirrus cloud fraction. This has implications for the temperature and water vapour budget in the tropical tropopause layer.

scholarly journals The effects of introducing the Amazonian squirrel monkey on the behavior of the northeast marmoset

2015 ◽  
Vol 45 (1) ◽  
pp. 29-34 ◽  
Author(s):  
Fátima Luciana Miranda CAMAROTTI ◽  
Valdir Luna da SILVA ◽  
Maria Adélia Borstelmann de OLIVEIRA
Keyword(s):  
Squirrel Monkey ◽  
Native Species ◽  
Callithrix Jacchus ◽  
Observation Time ◽  
Saimiri Sciureus ◽  
Significant Difference ◽  
Negative Effect ◽  
Total Observation Time ◽  
Total Observation ◽  
The Impact

The squirrel monkey Saimiri sciureus, an endemic primate of the Amazonian Basin, has been introduced in many localities of the Atlantic Forest biome. Introduced exotic species gain a competitive advantage in their new environment because of a lack of natural predators, competitors or diseases. This advantage can result in a reduction in the resources for the endemic species. The aims of this work were to evaluate the level of adaptation, and monitor the forms of interaction and the impact caused by S. sciureus on the behavior of the native species Callithrix jacchus in the Saltinho Biological Reserve, Tamandaré, Pernambuco, Brazil. The behavior was assessed by use of scan sampling method, every 5 min. A total of 382 h (191 h or 2,292 scans per group) of time sampling was performed. Sixteen interactions were recorded. The interaction index was low and represented 2.4% of the total observation time. Interactions were significantly higher during the dry season (58.5%) relative to the rainy season (41.5%). Callithrix jacchus was intolerant to the presence of S. sciureus and the last one was more tolerant during the interactions. In the presence of S. sciureus, C. jacchus eating, foraging, resting, socializing, and self-grooming behaviors were reduced while alertness was increased. Territorial behavior showed no significant difference. In the presence of S. sciureus, on average, the group of marmosets assembled at a higher layer of the forest stratum. The results might indicate a negative effect of S. sciureus on the native species, C. jacchus.

scholarly journals The potential of polarization measurements from space at mm and sub-mm wavelengths for determining cirrus cloud parameters

2003 ◽  
Vol 3 (1) ◽  
pp. 39-48 ◽  
Author(s):  
J. Miao ◽  
K.-P. Johnsen ◽  
S. Buehler ◽  
A. Kokhanovsky
Keyword(s):  
Particle Shape ◽  
Characteristic Size ◽  
Cirrus Clouds ◽  
Ice Crystals ◽  
Particle Orientation ◽  
Cirrus Cloud ◽  
Polarization Measurements ◽  
Polarization Difference ◽  
Cloud Parameters ◽  
Particle Characteristic

Abstract. The millimeter and sub-millimeter waves have been attracting a lot of attention recently in the cloud remote sensing community. This is largely because of their potential use in measuring cirrus cloud parameters with airborne or space-borne radiometers. In this study, we examine the possibility of using polarization measurements in this frequency range to get information on the microphysical properties of cirrus clouds. By using a simple radiative transfer model, we calculated the brightness temperature differences at the vertical and horizontal polarization channels for the following seven frequencies: 90, 157, 220, 340, 463, 683, and 874 GHz. The ice crystals in cirrus clouds are modeled with nearly spherical particles, circular cylinder, and circular plate, as well as with mixtures of these types. We found that the polarization difference signal shows a unique "resonance'' feature with the change of ice particle characteristic size: it has a strong response only in a certain range of ice particle size, beyond that range it approaches zero. The size range where this resonance happens depends to a large extent on particle shape and aspect ratio, but to a much less extent on particle orientation. This resonance feature appears even when ice clouds are composed of a mixture of ice crystals in different shapes, although the magnitude and the position of the resonance peak may change, depending on how the mixture is made. Oriented particles generally show larger polarization difference than randomly oriented ones, and plates have larger polarization difference than cylinders. However, the state of particle orientation has a significantly stronger effect on the polarization difference than the particle shape (cylinder or plate). This makes it difficult to distinguish particle shapes using millimeter and sub-millimeter radiometric measurements, if there is no information available on particle orientations. However, if the state of particle shape mixture can be predetermined by other approaches, polarization measurements can help to determine ice particle characteristic size and orientation. This information, in turn, will benefit our retrieval of the ice water path of cirrus clouds.

Incidence and severity of prostate cancer (PCa) in 792 hypogonadal men with and without long-term testosterone therapy (TTh): Results from a controlled registry study.

2018 ◽  
Vol 36 (6_suppl) ◽  
pp. 167-167
Author(s):  
Ahmad Haider ◽  
Karim Sultan Haider
Keyword(s):  
Radical Prostatectomy ◽  
Gleason Score ◽  
Transrectal Ultrasound ◽  
Digital Rectal Examination ◽  
Tumor Grade ◽  
Tumor Stage ◽  
Observation Time ◽  
Testosterone Undecanoate ◽  
Total Observation Time ◽  
Total Observation

167 Background: There is no evidence that TTh in hypogonadal men increases PCa incidence or severity. A US-Scandinavian group recently found that men receiving TTh had lower risk of aggressive PCa (Loeb S et al., J Clin Oncol 2017; 35:1430-6). Methods: 412 men with testosterone ≤350 ng/dL and symptoms received testosterone undecanoate 1000 mg every 3 months for up to 12 years. 380 hypogonadal men (57-74) opted against TTh. Median follow-up: 9 years. Total observation time covered approximately 6,400 patient-years. Prostate volume (PV) and PSA were measured and digital rectal examination/transrectal ultrasound performed before treatment/observation initiation and then every 3-6 months (T-group) or once or twice per year (CTRL). Biopsies were performed when indicated according to EAU guidelines. Results: In the T-group, 11 men (2.7%) were diagnosed with PCa. In CTRL, 34 (8.9%) were diagnosed with PCa. The incidence per 10,000 years was 33 in the T-group and 108 in CTRL. The mean baseline age of PCa patients was 65.2 years in the T-group and 64.3 in CTRL. All PCa diagnoses in the T-group were made within the first 18 months of treatment initiation. In CTRL, PCa was diagnosed at any time during the observation time. In the T-group, radical prostatectomy was performed in all men. All but 1 patient had a Gleason score (GS) ≤6, and all but 1 a predominant GS of 3. Tumor grade was G2 in all 11 (100%), tumor stage T2a in 7 (64%), T2b in 3 (27%), and T2c in 1 (9%) patient(s). In CTRL, radical prostatectomy was performed in all but 6 patients. GS was > 6 in all 34 patients. 7 men had a GS of 7, 17 a GS of 8, and 10 a GS of 9. 2 men had a predominant Gleason score of 3, 22 had 4, and 10 had 5. Tumor grade was G2 in 6 (17.6%) and G3 in 28 (82.4%) patients, tumor stage T2c in 1 (0.3%), T3a in 3 (8.8%), T3b in 13 (38.2%) and T3c in 17 (50%) patients. In CTRL, biochemical recurrence occurred in 8 (23.5%) patients. These patients received androgen deprivation therapy (ADT). 10 (29.4%) patients died of whom 5 were on ADT. In the T-group, there were no biochemical recurrences or deaths during the observation time. Conclusions: In hypogonadal men, TTh may decrease PCa incidence compared to CTRL. PCa was less severe in the T-group.

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