scholarly journals BOREAS AFM-05 LEVEL-2 UPPER AIR NETWORK STANDARD PRESSURE LEVEL DATA

1999 ◽  
Author(s):  
A. BARR ◽  
A. K. BETTS
Keyword(s):  
Pressure Level ◽  
Level Data ◽  
Standard Pressure ◽  
Level 2

scholarly journals Phosgene distribution derived from MIPAS ESA v8 data: intercomparisons and trends

2021 ◽  
Author(s):  
Paolo Pettinari ◽  
Flavio Barbara ◽  
Simone Ceccherini ◽  
Bianca Maria Dinelli ◽  
Marco Gai ◽  
...  
Keyword(s):  
Direct Injection ◽  
Michelson Interferometer ◽  
European Space Agency ◽  
Pressure Level ◽  
Positive Trend ◽  
Polar Regions ◽  
Upper Troposphere ◽  
Mixing Ratios ◽  
Polar Orbiting Satellite ◽  
Level 2

Abstract. The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) measured the middle-infrared limb emission spectrum of the atmosphere from 2002 to 2012 on board ENVISAT, a polar-orbiting satellite. Recently, the European Space Agency (ESA) completed the final reprocessing of MIPAS measurements, using Version 8 of the Level 1 and Level 2 processors, which include more accurate models, processing strategies and auxiliary data. The list of retrieved gases has been extended, it now includes a number of new species with weak emission features in the MIPAS spectral range. The new retrieved trace species include carbonyl chloride (COCl2), also called phosgene. Due to its toxicity, its use has been reduced over the years, however it is still used by chemical industries for sevaeral applications. Besides its direct injection in the troposphere, stratospheric phosgene is mainly produced from the photolysis of CCl4, a molecule present in the atmosphere because of human activity. Since phosgene has a long stratospheric lifetime, it must be carefully monitored as it is involved in the ozone destruction cycles, especially over the winter polar regions. In this paper we exploit the ESA MIPAS Version 8 data in order to discuss the phosgene distribution, variability and trends in the middle and lower stratosphere and in the upper troposphere. The zonal averages show that phosgene volume mixing ratio is larger in the stratosphere, with a peak of 40 pptv between 50 and 30 hPa at equatorial latitudes, while at middle and polar latitudes it varies from 10 to 25 pptv. A moderate seasonal variability is observed in polar regions, mostly between 80 and 50 hPa. The comparison of MIPAS/ENVISAT COCl2 v.8 profiles with the ones retrieved from MIPAS/balloon and ACE-FTS measurements highlights a negative bias of about 2 pptv, mainly in polar and mid-latitude regions. Part of this bias is attributed to the fact that the ESA Level 2 v.8 processor uses an updated spectroscopic database. For the trend computation, a fixed pressure grid is used to interpolate the phosgene profiles and, for each pressure level, VMR monthly averages are computed in pre-defined 10°-wide latitude bins. Then, for each latitudinal bin and pressure level, a regression model has been fitted to the resulting time-series in order to derive the atmospheric trends. We find that the phosgene trends are different in the two hemispheres. The analysis shows that the stratosphere of the Northern Hemisphere is characterised by a negative trend, of about −7 pptv/decade, while in the Southern Hemisphere phosgene mixing ratios increase with a rate of the order of +4 pptv/decade. In the upper troposphere a positive trend is found in both hemispheres.

scholarly journals Phosgene distribution derived from MIPAS ESA v8 data: intercomparisons and trends

2021 ◽  
Vol 14 (12) ◽  
pp. 7959-7974
Author(s):  
Paolo Pettinari ◽  
Flavio Barbara ◽  
Simone Ceccherini ◽  
Bianca Maria Dinelli ◽  
Marco Gai ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Michelson Interferometer ◽  
European Space Agency ◽  
Pressure Level ◽  
Positive Trend ◽  
Polar Regions ◽  
Mixing Ratio ◽  
Upper Troposphere ◽  
Polar Orbiting Satellite ◽  
Level 2

Abstract. The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) measured the middle-infrared limb emission spectrum of the atmosphere from 2002 to 2012 on board ENVISAT, a polar-orbiting satellite. Recently, the European Space Agency (ESA) completed the final reprocessing of MIPAS measurements, using version 8 of the level 1 and level 2 processors, which include more accurate models, processing strategies, and auxiliary data. The list of retrieved gases has been extended, and it now includes a number of new species with weak emission features in the MIPAS spectral range. The new retrieved trace species include carbonyl chloride (COCl2), also called phosgene. Due to its toxicity, its use has been reduced over the years; however, it is still used by chemical industries for several applications. Besides its direct injection in the troposphere, stratospheric phosgene is mainly produced from the photolysis of CCl4, a molecule present in the atmosphere because of human activity. Since phosgene has a long stratospheric lifetime, it must be carefully monitored as it is involved in the ozone destruction cycles, especially over the winter polar regions. In this paper we exploit the ESA MIPAS version 8 data in order to discuss the phosgene distribution, variability, and trends in the middle and lower stratosphere and in the upper troposphere. The zonal averages show that phosgene volume mixing ratio is larger in the stratosphere, with a peak of 40 pptv (parts per trillion by volume) between 50 and 30 hPa at equatorial latitudes, while at middle and polar latitudes it varies from 10 to 25 pptv. A moderate seasonal variability is observed in polar regions, mostly between 80 and 50 hPa. The comparison of MIPAS–ENVISAT COCl2 v8 profiles with the ones retrieved from MIPAS balloon and ACE-FTS (Atmospheric Chemistry Experiment – Fourier Transform Spectrometer) measurements highlights a negative bias of about 2 pptv, mainly in polar and mid-latitude regions. Part of this bias is attributed to the fact that the ESA level 2 v8 processor uses an updated spectroscopic database. For the trend computation, a fixed pressure grid is used to interpolate the phosgene profiles, and, for each pressure level, VMR (volume mixing ratio) monthly averages are computed in pre-defined 10∘ wide latitude bins. Then, for each latitudinal bin and pressure level, a regression model has been fitted to the resulting time series in order to derive the atmospheric trends. We find that the phosgene trends are different in the two hemispheres. The analysis shows that the stratosphere of the Northern Hemisphere is characterized by a negative trend of about −7 pptv per decade, while in the Southern Hemisphere phosgene mixing ratios increase with a rate of the order of +4 pptv per decade. This behavior resembles the stratospheric trend of CCl4, which is the main stratospheric source of COCl2. In the upper troposphere a positive trend is found in both hemispheres.

Conducting Three-Level Longitudinal Analyses

2016 ◽  
Vol 37 (1) ◽  
pp. 7-58 ◽  
Author(s):  
James L. Peugh ◽  
Ronald H. Heck
Keyword(s):  
Repeated Measures ◽  
Cluster Sampling ◽  
Longitudinal Analyses ◽  
Cross Sectional ◽  
Data Analyses ◽  
Level Data ◽  
Level 3 ◽  
Level 1 ◽  
Data Analytic ◽  
Level 2

Researchers in the field of early adolescence interested in quantifying the environmental influences on a response variable of interest over time would use cluster sampling (i.e., obtaining repeated measures from students nested within classrooms and/or schools) to obtain the needed sample size. The resulting longitudinal data would be nested at three levels (e.g., repeated measures [Level 1], collected across participants [Level 2], and nested within different schools [Level 3]). A previous publication addressed statistical analysis issues specific to cross-sectional three-level data analytic designs. This article expands upon the previous cross-sectional three-level publication to address topics specific to longitudinal three-level data analyses efforts. Although all analysis examples are demonstrated using SAS, the equivalent SPSS and Mplus syntax scripts, as well as the generated example data and additional supplemental materials, are available online.

scholarly journals Application of selected computational intelligence methods to sound level modelling based on traffic intensity in thoroughfare

2019 ◽  
Vol 254 ◽  
pp. 02038 ◽  
Author(s):  
Michał Kekez
Keyword(s):  
Random Forest ◽  
Computational Intelligence ◽  
Sound Pressure ◽  
Prediction Method ◽  
Sound Level ◽  
Pressure Level ◽  
Analytical Models ◽  
Traffic Intensity ◽  
Level Data ◽  
Computational Intelligence Methods

The aim of the paper was to build the models of sound pressure level as a function of traffic intensity in thoroughfare. The models were built by using artificial analytical models or regression trees. The former included Nordic Prediction Method. The latter were represented by Random Forest and Cubist. The analysis of accuracy of all obtained models was conducted. The best models can be used in the process of reconstruction of equivalent sound level data.

scholarly journals Momentum forcing of the QBO by equatorial waves in recent reanalyses

2015 ◽  
Vol 15 (4) ◽  
pp. 5175-5202
Author(s):  
Y.-H. Kim ◽  
H.-Y. Chun
Keyword(s):  
Gravity Wave ◽  
Gravity Waves ◽  
Pressure Level ◽  
Equatorial Waves ◽  
Kelvin Wave ◽  
Wave Forcing ◽  
Opposite Phase ◽  
Level Data ◽  
Equatorial Wave ◽  
Wave Modes

Abstract. The momentum forcing by equatorial waves to the QBO is estimated using recent reanalyses. Based on the estimation using the conventional pressure level datasets, the forcing by the Kelvin waves (3–9 m s−1 month−1) dominates the net forcing by all equatorial wave modes in the easterly-to-westerly transition phase at 30 hPa (3–11 m s−1 month−1). In the opposite phase, the net forcing by equatorial wave modes is small (1–5 m s−1 month−1). By comparing the results with those from the native model-level dataset of the ERA-Interim reanalysis, it is suggested that the use of conventional-level data causes the Kelvin wave forcing to be underestimated by 2–4 m s−1 month−1. The momentum forcing by mesoscale gravity waves, which are unresolved in the reanalyses, is deduced from the residual of the zonal wind tendency equation. In the easterly-to-westerly phase at 30 hPa, the mesoscale gravity wave forcing is found to be smaller than the resolved wave forcing, whereas the gravity wave forcing dominates over the resolved wave forcing in the opposite phase. Finally, we discuss the uncertainties in the wave forcing estimates using the reanalyses.

Efficiency and Robustness of Alternative Estimators for Two- and Three-level Models: The Case of NAEP

2001 ◽  
Vol 26 (4) ◽  
pp. 411-429 ◽  
Author(s):  
Yuk Fai Cheong ◽  
Randall P. Fotiu ◽  
Stephen W. Raudenbush
Keyword(s):  
Hierarchical Model ◽  
Large Scale ◽  
Variance Estimation ◽  
Level Structure ◽  
Covariance Structure ◽  
Standard Errors ◽  
Robust Estimator ◽  
Level Data ◽  
Level 2 ◽  
Level Analysis

This article investigates the efficiency and robustness of alternative estimators of regression coefficients for three-level data. To study student achievement, researchers might formulate a standard regression model or a hierarchical model with a two- or three-level structure. Having chosen the model, the researchers might employ either a model-based or a robust estimator of the standard errors. A simulation study showed that, as expected, the hierarchical model analyses produced more efficient point estimates than did analyses that ignored the covariance structure in the data, even when the normality assumption was violated. When samples were fairly large, the three-level analyses produced sound standard errors. In contrast, single-level analysis yielded seriously biased standard errors for coefficients defined at level 3 and level 2; and two-level analysis yielded biased standard errors for coefficients defined at level 2. These biases in standard error estimates were largely corrected by robust variance estimation. Implications of the results for analyzing NAEP and other large-scale surveys such as the Early Childhood Longitudinal Study (ECLS) and the Third International Mathematics and Science Study (TIMSS) are discussed.

scholarly journals Impact of the Vertical Resolution of Analysis Data on the Estimates of Large-Scale Inertio-Gravity Energy

2012 ◽  
Vol 140 (7) ◽  
pp. 2297-2307 ◽  
Author(s):  
Nedjeljka Žagar ◽  
Koji Terasaki ◽  
Hiroshi L. Tanaka
Keyword(s):  
Large Scale ◽  
Level Density ◽  
Analysis Data ◽  
Temporal Variations ◽  
Vertical Resolution ◽  
Level Data ◽  
Standard Pressure ◽  
The Tropics ◽  
Relative Change ◽  
Vertical Level

Abstract This paper deals with the large-scale inertio-gravity (IG) wave energy in the operational ECMWF analyses in July 2007. Energy percentages of the IG waves obtained from the standard-pressure-level data are compared to those derived from various discretizations of the model-level data. The results show a small albeit systematic increase of the IG energy percentage as the vertical level density increases from the standard-pressure levels toward the model-level density; the small relative change is explained by the sufficient vertical resolution to resolve the large-scale IG waves in the tropics that make the majority of the global IG energy on large scales. A relatively larger increase of the IG energy is obtained when the mesospheric model levels are included; however, the analyses at these levels in July 2007 are less reliable. Furthermore, two numerical methods for the normal-mode function (NMF) decomposition are shown to provide similar results. The decomposition of atmospheric analyses into the NMF series is proposed as a tool to analyze the spatial and temporal variations of the large-scale equatorial waves and their role in global energetics.

scholarly journals SITUATION OF HYPERTENSION IN PEOPLE FORM 25 AGO OR MORE IN THAI BINH PROVINCE, 2017

2021 ◽  
Vol 62 (4) ◽  
Author(s):  
Hoang Van Binh ◽  
Tran Thi Nhu Quynh
Keyword(s):  
Blood Pressure Level ◽  
Cross Sectional Study ◽  
Pressure Level ◽  
Cluster Sampling ◽  
Age Group ◽  
Sectional Study ◽  
Cross Sectional ◽  
High Blood Pressure Level ◽  
Level 1 ◽  
Level 2

 A cross-sectional study was carried out in 2017, with the method of cluster sampling (PPS) to select30 communes/wards in 8 districts/cities in Thai Binh province. A total of 1450 adults from 25 ago ormore the results showed that:The prevalence rate of hypertension was 29.8%, of which men account for 36.5%, 22.0% higherthan that of women (p<0.05), mainly high blood pressure level 1 (42.3%), level 2 (35.4%) and level3 (22.3%).The rate of hypertension tends to increase gradually by age group, the group aged 70 and overaccounts for the highest proportion (36.4%), the age group 60-69 was 34.8%, the age group 40-59was 31.5% and the lowest of 25-39 age group (16.1%) (p<0.05).

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