scholarly journals Cloud-State-Dependent Sampling in AIRS Observations Based on CloudSat Cloud Classification

2013 ◽  
Vol 26 (21) ◽  
pp. 8357-8377 ◽  
Author(s):  
Qing Yue ◽  
Eric J. Fetzer ◽  
Brian H. Kahn ◽  
Sun Wong ◽  
Gerald Manipon ◽  
...  
Keyword(s):  
Analysis Data ◽  
Atmospheric Infrared Sounder ◽  
Boundary Layer Clouds ◽  
State Dependent ◽  
Geographical Regions ◽  
Realistic Representation ◽  
The Mean ◽  
The Tropics ◽  
Ecmwf Model ◽  
Pixel Scale

Abstract The precision, accuracy, and potential sampling biases of temperature T and water vapor q vertical profiles obtained by satellite infrared sounding instruments are highly cloud-state dependent and poorly quantified. The authors describe progress toward a comprehensive T and q climatology derived from the Atmospheric Infrared Sounder (AIRS) suite that is a function of cloud state based on collocated CloudSat observations. The AIRS sampling rates, biases, and center root-mean-square differences (CRMSD) are determined through comparisons of pixel-scale collocated ECMWF model analysis data. The results show that AIRS provides a realistic representation of most meteorological regimes in most geographical regions, including those dominated by high thin cirrus and shallow boundary layer clouds. The mean AIRS observational biases relative to the ECMWF analysis between the surface and 200 hPa are within ±1 K in T and from −1 to +0.5 g kg−1 in q. Biases because of cloud-state-dependent sampling dominate the total biases in the AIRS data and are largest in the presence of deep convective (DC) and nimbostratus (Ns) clouds. Systematic cold and dry biases are found throughout the free troposphere for DC and Ns. Somewhat larger biases are found over land and in the midlatitudes than over the oceans and in the tropics, respectively. Tropical and oceanic regions generally have a smaller CRMSD than the midlatitudes and over land, suggesting agreement of T and q variability between AIRS and ECMWF in these regions. The magnitude of CRMSD is also strongly dependent on cloud type.

scholarly journals Space-borne observation of methane from atmospheric infrared sounder version 6: validation and implications for data analysis

2015 ◽  
Vol 8 (8) ◽  
pp. 8563-8597 ◽  
Author(s):  
X. Xiong ◽  
F. Weng ◽  
Q. Liu ◽  
E. Olsen
Keyword(s):  
Data Analysis ◽  
Cloud Amount ◽  
Retrieval Algorithm ◽  
Atmospheric Methane ◽  
Atmospheric Infrared Sounder ◽  
Northern Latitudes ◽  
Standard Product ◽  
The Mean ◽  
The Tropics ◽  
Recent Version

Abstract. Atmospheric Methane (CH4) is generated as a standard product in recent version of the hyperspectral Atmospheric Infrared Sounder (AIRS-V6) aboard NASA's Aqua satellite at the NASA Goddard Earth Sciences Data and Information Services Center (NASA/GES/DISC). Significant improvements in AIRS-V6 was expected but without a thorough validation. This paper first introduced the improvements of CH4 retrieval in AIRS-V6 and some characterizations, then presented the results of validation using ~ 1000 aircraft profiles from several campaigns spread over a couple of years and in different regions. It was found the mean biases of AIRS CH4 at layers 343–441 and 441–575 hPa are −0.76 and −0.05 % and the RMS errors are 1.56 and 1.16 %, respectively. Further analysis demonstrates that the errors in the spring and in the high northern latitudes are larger than in other seasons or regions. The error is correlated with Degree of Freedoms (DOFs), particularly in the tropics or in the summer, and cloud amount, suggesting that the "observed" spatiotemporal variation of CH4 by AIRS is imbedded with some artificial impact from the retrieval sensitivity in addition to its variation in reality, so the variation of information content in the retrievals needs to be taken into account in data analysis of the retrieval products. Some additional filtering (i.e. rejection of profiles with obvious oscillation as well as those deviating greatly from the norm) for quality control is recommended for the users to better utilize AIRS-V6 CH4, and their implementation in the future versions of the AIRS retrieval algorithm is under consideration.

scholarly journals The Impact of the Tracer Size and the Temporal Gap between Images in the Extraction of Atmospheric Motion Vectors

2014 ◽  
Vol 31 (8) ◽  
pp. 1761-1770 ◽  
Author(s):  
Javier García-Pereda ◽  
Régis Borde
Keyword(s):  
Motion Vector ◽  
Mediterranean Area ◽  
Small Impact ◽  
Vector Difference ◽  
Atmospheric Motion ◽  
The Mean ◽  
Atmospheric Motion Vectors ◽  
Ecmwf Model ◽  
The Impact ◽  
Pixel Scale

Abstract The goal of this paper is to show the impact of the tracer size and the temporal gap between images in atmospheric motion vector (AMV) extraction schemes. A test has been performed using NWC SAF/High Resolutions Winds AMV software for different configurations with a tracer size varying between 8 × 8 and 40 × 40 pixels and a temporal gap between images varying between 5 and 90 min. AMVs have been extracted for four different MSG/SEVIRI channels (HRVIS, VIS0.8, WV6.2, and IR10.8) over the European and Mediterranean area for a 6-month period (January–June 2010). The AMV performances have been tested against radiosonde winds and ECMWF model analysis winds. The results show a small impact of the tracer size on the number of valid AMVs, which is, however, more significant for clear air AMVs, and a significant impact of the temporal gap between images. The largest number of valid AMVs has been found in general for a temporal gap of 5 min for the 1-km pixel scale and for a temporal gap of 10 min for the 3-km pixel scale. Results also show a decrease of the mean AMV speed and the normalized BIAS (NBIAS) with larger tracer sizes, and a relatively small impact of the temporal gap on these parameters. Finally, the results show minimum values of the normalized root-mean-square vector difference (NRMSVD) for intermediate temporal gaps between 15 and 30 min with a relatively small impact of the tracer size on this parameter.

scholarly journals Genetic diversity of Avena strigosa Schreb. ecotypes on the basis of isoenzyme markers

2009 ◽  
Vol 15 (1) ◽  
pp. 23-28 ◽  
Author(s):  
Katarzyna Kubiak
Keyword(s):  
Genetic Diversity ◽  
Genetic Similarity ◽  
Avena Strigosa ◽  
Total Genetic Diversity ◽  
Geographical Regions ◽  
The World ◽  
Total Variability ◽  
The Mean ◽  
Intrapopulation Diversity ◽  
Very High

Genetic diversity ofAvena strigosaSchreb. ecotypes on the basis of isoenzyme markersGenetic diversity was analyzed in 19 ecotypes of the diploid oatA. strigosaoriginating from various geographical regions of the world. Six isoenzyme systems (AAT, ACP, EST, LAP, MDH, PX) were studied and 16 loci were identified. Only two loci (Est4andMdh2) were polymorphic. Ecotypes were characterized by the percentage of polymorphic loci (P=3.3%), the mean number of alleles per locus (A=1.04) and intrapopulation diversity (HS=0.013). Total genetic diversity (HT=0.07) and interpopulation diversity (DST=0.057) were examined as well. The value of the coefficient of gene differentiation (GST=0.821) indicated that diversity among populations was an important contributor to total variability. Genetic similarity betweenA. strigosapopulations was very high (IN=0.94). Cluster analysis did not demonstrate strongly differentiated groups among the ecotypes examined.

scholarly journals Analysis of stimulus-related activity in rat auditory cortex using complex spectral coefficients

2013 ◽  
Vol 110 (3) ◽  
pp. 621-639 ◽  
Author(s):  
Bryan M. Krause ◽  
Matthew I. Banks
Keyword(s):  
Low Frequency ◽  
Phase Changes ◽  
Induced Response ◽  
Top Down ◽  
Time Frequency ◽  
State Dependent ◽  
Spectral Coefficients ◽  
The Mean ◽  
Sensory Responses ◽  
Mean Variance

The neural mechanisms of sensory responses recorded from the scalp or cortical surface remain controversial. Evoked vs. induced response components (i.e., changes in mean vs. variance) are associated with bottom-up vs. top-down processing, but trial-by-trial response variability can confound this interpretation. Phase reset of ongoing oscillations has also been postulated to contribute to sensory responses. In this article, we present evidence that responses under passive listening conditions are dominated by variable evoked response components. We measured the mean, variance, and phase of complex time-frequency coefficients of epidurally recorded responses to acoustic stimuli in rats. During the stimulus, changes in mean, variance, and phase tended to co-occur. After the stimulus, there was a small, low-frequency offset response in the mean and modest, prolonged desynchronization in the alpha band. Simulations showed that trial-by-trial variability in the mean can account for most of the variance and phase changes observed during the stimulus. This variability was state dependent, with smallest variability during periods of greatest arousal. Our data suggest that cortical responses to auditory stimuli reflect variable inputs to the cortical network. These analyses suggest that caution should be exercised when interpreting variance and phase changes in terms of top-down cortical processing.

scholarly journals Emission location dependent ozone depletion potentials for very short-lived halogenated species

2010 ◽  
Vol 10 (6) ◽  
pp. 16277-16305
Author(s):  
I. Pisso ◽  
P. H. Haynes ◽  
K. S. Law
Keyword(s):  
Northern Hemisphere ◽  
Ozone Depletion ◽  
Degradation Products ◽  
Stratospheric Ozone ◽  
Surface Emission ◽  
Spatial And Seasonal Variation ◽  
Geographical Regions ◽  
Simplifying Assumptions ◽  
Hemisphere Winter ◽  
The Tropics

Abstract. We present trajectory-based estimates of Ozone Depletion Potentials (ODPs) for very short-lived halogenated source gases as a function of surface emission location. The ODPs are determined by the fraction of source gas and its degradation products which reach the stratosphere, depending primarily on tropospheric transport and chemistry, and the effect of the resulting reactive halogen in the stratosphere, which is determined by stratospheric transport and chemistry, in particular by stratospheric residence time. Reflecting the different timescales and physico-chemical processes in the troposphere and stratosphere, the estimates are based on calculation of separate ensembles of trajectories for the troposphere and stratosphere. A methodology is described by which information from the two ensembles can be combined to give the ODPs. The ODP estimates for a species with a 20 d lifetime, representing a compound like n-propyl bromide, are presented as an example. The estimated ODPs show strong geographical and season variation, particularly within the tropics. The values of the ODPs are sensitive to the inclusion of a convective parametrization in the trajectory calculations, but the relative spatial and seasonal variation is not. The results imply that ODPs are largest for emissions from South and South-East Asia during Northern Hemisphere summer and from the Western Pacific during Northern Hemisphere winter. Large ODPs are also estimated for emissions throughout the tropics with also non-negligible values extending into northern mid-latitudes particularly in the summer. These first estimates, which include some simplifying assumptions, show larger ODP values than previous studies, particularly over Southern Asia, suggesting that emissions of short-lived halogen source gases in certain geographical regions could have a significant impact on stratospheric ozone depletion.

The composition of milk of British Alpine and Anglo–Nubian goats imported into Trinidad

1972 ◽  
Vol 39 (3) ◽  
pp. 381-385 ◽  
Author(s):  
C. Devendra
Keyword(s):  
Milk Composition ◽  
Pennisetum Purpureum ◽  
Dairy Goats ◽  
Mineral Contents ◽  
Total N ◽  
Total Solids ◽  
Concentrate Mixture ◽  
The Mean ◽  
Inadequate Nutrition ◽  
The Tropics

SummaryThe variations in the composition of milk over an 18-week period from lactating British Alpine and Anglo–Nubian goats imported into Trinidad are reported. The animals were fed Napier grass (Pennisetum purpureum) ad lib. and 2 lb of a proprietary concentrate mixture daily.The mean percentage contents of the milks of British Alpine and Anglo–Nubian goats were: total solids 11·49±0·22, 12·17±0·28; butterfat 3·42±0·18, 4·06±0·22; total N 0·462±0·04, 0·530±0·07; ash 0·78±0·02, 0·79±0·03 and ‘lactose’ 4·38±0·28, 4·05±0·55. Anglo–Nubian goats had a higher content of percentage total solids, fat, total N and ash. For all constituents the coefficient of variation between weeks was higher for Anglo–Nubian goats. No significant trends were found between weeks for each of the components analysed for both breeds. Statistically significant correlations (P < 0·01) were found between percentage fat and percentage total N for both breeds.The mean mineral contents (mg/100ml) for the milks of British Alpine and Anglo–Nubian goats were: Na 52·6±4·6, 55·5±1·9; K164·0±8·4, 133·4±11·4; Ca 85·5±11·6, 89·9±9·8; Mg 13·2±3·8, 10·2±1·6 and P 74·7±3·9, 82·1±3·9. British Alpine goat's milk had a higher content of K and that of Anglo–Nubian goats had a higher content of P; both differences were statistically significant (P < 0·01).The milk composition figures in this study together with those from a similar study in Guadeloupe suggest that the values are low and considerably lower in comparison with the same breeds of goats in a temperate environment. This could be a feature of dairy goats imported into the tropics due perhaps to inadequate nutrition. Much more information is needed to verify this possibility.

Assessing the sustainability of yellow anaconda (Eunectes notaeus) harvest in northeastern Argentina

2020 ◽  
Author(s):  
Bruno Camera ◽  
Christine Stüssmann ◽  
Itxaso Quintana ◽  
Tomás Waller ◽  
Mariano Barros ◽  
...  
Keyword(s):  
Wildlife Management ◽  
Sustainable Use ◽  
Management Program ◽  
Gradual Reduction ◽  
Hunting Season ◽  
Time Period ◽  
History Of ◽  
The Mean ◽  
The Tropics ◽  
Northeastern Argentina

Abstract Sustainable wildlife management is required to guarantee source species viability; however, it is practiced rarely in the tropics. The yellow anaconda (Eunectes notaeus) has a long history of being harvested for its leather. Since 2002 its harvest has operated under a management program in northeastern Argentina, which relies on adaptive management through limiting the minimum anaconda length, number of hunters and restricting the hunting season. We investigated the effects of the anaconda harvest on its biological parameters based on 2002-2016 data. Here we show that the levels of species exploitation are sustainable. The gradual reduction in the annual hunting effort, due to a decrease in number of hunters and hunting season duration, reduced the total number of anacondas harvested. Conversely, captures per unit effort increased across the study time-period. There was no variation in the mean length of anacondas harvested, or in largest anaconda sizes. Though more females than males were caught, the sex ratio did not vary significantly. We also found that a decrease in mean temperature positively influenced anaconda harvest and the captures of giant individuals. Because sustainable use is a powerful tool for conservation, those discoveries are highly applicable to other species and regions.

scholarly journals Variability and quasi-decadal changes in the methane budget over the period 2000–2012

2017 ◽  
Author(s):  
Marielle Saunois ◽  
Philippe Bousquet ◽  
Benjamin Poulter ◽  
Anna Peregon ◽  
Philippe Ciais ◽  
...  
Keyword(s):  
Biomass Burning ◽  
Methane Emissions ◽  
Data Driven ◽  
Atmospheric Methane ◽  
Top Down ◽  
Bottom Up ◽  
Ch4 Emissions ◽  
Ensemble Mean ◽  
The Mean ◽  
The Tropics

Abstract. Following the recent Global Carbon project (GCP) synthesis of the decadal methane (CH4) budget over 2000–2012 (Saunois et al., 2016), we analyse here the same dataset with a focus on quasi-decadal and inter-annual variability in CH4 emissions. The GCP dataset integrates results from top-down studies (exploiting atmospheric observations within an atmospheric inverse-modelling frameworks) and bottom-up models, inventories, and data-driven approaches (including process-based models for estimating land surface emissions and atmospheric chemistry, inventories of anthropogenic emissions, and data-driven extrapolations). The annual global methane emissions from top-down studies, which by construction match the observed methane growth rate within their uncertainties, all show an increase in total methane emissions over the period 2000–2012, but this increase is not linear over the 13 years. Despite differences between individual studies, the mean emission anomaly of the top-down ensemble shows no significant trend in total methane emissions over the period 2000–2006, during the plateau of atmospheric methane mole fractions, and also over the period 2008–2012, during the renewed atmospheric methane increase. However, the top-down ensemble mean produces an emission shift between 2006 and 2008, leading to 22 [16–32] Tg CH4 yr−1 higher methane emissions over the period 2008–2012 compared to 2002–2006. This emission increase mostly originated from the tropics with a smaller contribution from mid-latitudes and no significant change from boreal regions. The regional contributions remain uncertain in top-down studies. Tropical South America and South and East Asia seems to contribute the most to the emission increase in the tropics. However, these two regions have only limited atmospheric measurements and remain therefore poorly constrained. The sectorial partitioning of this emission increase between the periods 2002–2006 and 2008–2012 differs from one atmospheric inversion study to another. However, all top-down studies suggest smaller changes in fossil fuel emissions (from oil, gas, and coal industries) compared to the mean of the bottom-up inventories included in this study. This difference is partly driven by a smaller emission change in China from the top-down studies compared to the estimate in the EDGARv4.2 inventory, which should be revised to smaller values in a near future. Though the sectorial partitioning of six individual top-down studies out of eight are not consistent with the observed change in atmospheric 13CH4, the partitioning derived from the ensemble mean is consistent with this isotopic constraint. At the global scale, the top-down ensemble mean suggests that, the dominant contribution to the resumed atmospheric CH4 growth after 2006 comes from microbial sources (more from agriculture and waste sectors than from natural wetlands), with an uncertain but smaller contribution from fossil CH4 emissions. Besides, a decrease in biomass burning emissions (in agreement with the biomass burning emission databases) makes the balance of sources consistent with atmospheric 13CH4 observations. The methane loss (in particular through OH oxidation) has not been investigated in detail in this study, although it may play a significant role in the recent atmospheric methane changes.

Should we start a nationwide screening program for critical congenital heart disease in Turkey? A pilot study on four centres with different altitudes

2019 ◽  
Vol 29 (4) ◽  
pp. 475-480
Author(s):  
Dilek Dilli ◽  
Vehbi Doğan ◽  
Banu M. Özyurt ◽  
Abdullah Özyurt ◽  
Nilay Hakan ◽  
...  
Keyword(s):  
Congenital Heart Disease ◽  
Heart Disease ◽  
Pulse Oximetry ◽  
Congenital Heart ◽  
Screening Program ◽  
Critical Congenital Heart Disease ◽  
Multi Centre Study ◽  
Geographical Regions ◽  
The Mean ◽  
Different Altitudes

AbstractBackground:To investigate the feasibility of critical congenital heart disease (CCHD) screening test by pulse oximetry in four geographical regions of Turkey with different altitudes, before implementation of a nationwide screening program.Methods:It was a prospective multi-centre study performed in four centres, between December, 2015 and May, 2017. Pre- and post-ductal oxygen saturations and perfusion indices (PI) were measured using Masimo Radical-7 at early postnatal days. The results were evaluated according to the algorithm recommended by the American Academy of Pediatrics. Additionally, a PI value <0.7 was accepted to be significant.Results:In 4888 newborns, the mean screening time was 31.5 ± 12.1 hours. At first attempt, the mean values of pre- and post-ductal measurements were: saturation 97.3 ± 1.8%, PI 2.8 ± 2.0, versus saturation 97.7 ± 1.8%, PI 2.3±1.3, respectively. Pre-ductal saturations and PI and post-ductal saturations were the lowest in Centre 4 with the highest altitude. Overall test positivity rate was 0.85% (n = 42). CCHD was detected in six babies (0.12%). Of them, right hand (91 ± 6.3) and foot saturations (92.1 ± 4.3%) were lower compared to ones with non-CCHD and normal variants (p <0.05, for all comparisons). Sensitivity, specificity, positive and negative predictive values, and likelihood ratio of the test were: 83.3%, 99.9%, 11.9%, 99.9%, and 99.2%, respectively.Conclusion:This study concluded that pulse oximetry screening is an effective screening tool for congenital heart disease in newborns at different altitudes. We support the implementation of a national screening program with consideration of altitude differences for our country.

scholarly journals A Multidiagnostic Intercomparison of Tropical-Width Time Series Using Reanalyses and Satellite Observations

2012 ◽  
Vol 25 (4) ◽  
pp. 1061-1078 ◽  
Author(s):  
Sean M. Davis ◽  
Karen H. Rosenlof
Keyword(s):  
Longwave Radiation ◽  
Hadley Cell ◽  
Radiosonde Data ◽  
Full Time ◽  
Robust Detection ◽  
Time Period ◽  
Wide Range ◽  
The Mean ◽  
Yield Trends ◽  
The Tropics

Abstract Poleward migration of the latitudinal edge of the tropics of 0.25°–3.0° decade−1 has been reported in several recent studies based on satellite and radiosonde data and reanalysis output covering the past ~30 yr. The goal of this paper is to identify the extent to which this large range of trends can be explained by the use of different data sources, time periods, and edge definitions, as well as how the widening varies as a function of hemisphere and season. Toward this end, a suite of tropical edge latitude diagnostics based on tropopause height, winds, precipitation–evaporation, and outgoing longwave radiation (OLR) are analyzed using several reanalyses and satellite datasets. These diagnostics include both previously used definitions and new definitions designed for more robust detection. The wide range of widening trends is shown to be primarily due to the use of different datasets and edge definitions and only secondarily due to varying start–end dates. This study also shows that the large trends (&gt;~1° decade−1) previously reported in tropopause and OLR diagnostics are due to the use of subjective definitions based on absolute thresholds. Statistically significant Hadley cell expansion based on the mean meridional streamfunction of 1.0°–1.5° decade−1 is found in three of four reanalyses that cover the full time period (1979–2009), whereas other diagnostics yield trends of −0.5°–0.8° decade−1 that are mostly insignificant. There are indications of hemispheric and seasonal differences in the trends, but the differences are not statistically significant.

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