A statistical analysis method estimating dust aerosol-ice cloud interactions using global circulation model and satellite data

2020 ◽  
Author(s):  
Thomas Offenwanger ◽  
Christoph Beck ◽  
Thomas Popp ◽  
Johannes Hendricks ◽  
Mattia Righi
Keyword(s):  
Statistical Analysis ◽  
Satellite Data ◽  
Circulation Model ◽  
Dust Aerosol ◽  
Analysis Method ◽  
Global Circulation Model ◽  
Ice Cloud ◽  
Global Circulation ◽  
Cloud Properties ◽  
Statistical Analysis Method

<p>A statistical analysis method to quantify dust aerosol interactions with ice cloud properties using IASI satellite data has been developed and published by L. Klüser et al. 2017. Key components of analyzing cloud properties are their classification by aerosol load and their normalization in respect to the meteorological state using a Bayes-approach. Comparing histograms of cloud properties for different aerosol classes gives then insight in statistical changes of their distribution. Using the same method twice on IASI-IMARS satellite retrieval and EMAC-MADE3 global circulation model data yields valuable insights on changes in cloud forming and lifecycle behavior inflicted by dust aerosol pollution. Overcoming scale differences between observation and simulation data sets has been a major obstacle as they have evident impact on the analysis results. Therefore, a statistical downscaling method has been customized to EMAC-MADE3 model data that focuses on preservation of critical processes while still approximating fine-scale patterns below model resolution. Both statistical analysis results for model and satellite data show clear aerosol impact on cloud property distributions with varying magnitudes and demonstrate the necessity of downscaling. More detailed analysis conducted with an increased number of aerosol classes shows quantifiable trends in aerosol impact on cloud properties.</p>

scholarly journals Financial Performance of Non-oil Manufacturing Companies Listed on the Libyan Stock Market (LSM): Mixed Methods Study

2019 ◽  
Vol 9 (4) ◽  
pp. 77
Author(s):  
Khalifa Mohamed Khalifa Omar
Keyword(s):  
Statistical Analysis ◽  
Stock Market ◽  
Financial Performance ◽  
Manufacturing Companies ◽  
Analysis Method ◽  
Affecting Factors ◽  
Structured Interviews ◽  
Turnover Ratio ◽  
Statistical Effect ◽  
Statistical Analysis Method

The major objective of this study is to assess the financial performance and identify the affecting factors in this performance of non-oil manufacturing companies from 1999 to 2008. The study sample consisted of all non-oil manufacturing companies' enlisted at Libyan stock market which count (8). The data collected was analyzed by using statistical analysis method such as descriptive statistics, correlation test, Multiple- regression, as well as semi-structured interviews method. The results regarding to the statistical analysis method (net working capital, inventory turnover ratio, selling and general administrative expenses ratio, and company size and company age), have a positive statistical effect on the financial performance(ROA), while the variables of (current ratio, quick ratio and account receivable turnover ratio), have a negative statistical effect on the financial performance (ROA). The results regarding to semi-structured interviews method, reveal that the respondents in the interviews were confirmed that the selected factors have a significant effect on financial performance (ROA). The researcher recommended that the selected companies must consider the listed decision on the Libyan stock market; even when their financial performance is good.

scholarly journals Variability of Prognostic Results Based on Biological Parameters in Sickle Cell Disease Cohort Studies in Children: What Should Clinicians Know?

Children ◽  
2021 ◽  
Vol 8 (2) ◽  
pp. 143
Author(s):  
Julie Sommet ◽  
Enora Le Roux ◽  
Bérengère Koehl ◽  
Zinedine Haouari ◽  
Damir Mohamed ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Sickle Cell Disease ◽  
Cohort Studies ◽  
Statistical Methods ◽  
Sickle Cell ◽  
Biological Parameters ◽  
Analysis Method ◽  
Cell Disease ◽  
Statistical Analysis Method

Background: Many pediatric studies describe the association between biological parameters (BP) and severity of sickle cell disease (SCD) using different methods to collect or to analyze BP. This article assesses the methods used for collection and subsequent statistical analysis of BP, and how these impact prognostic results in SCD children cohort studies. Methods: Firstly, we identified the collection and statistical methods used in published SCD cohort studies. Secondly, these methods were applied to our cohort of 375 SCD children, to evaluate the association of BP with cerebral vasculopathy (CV). Results: In 16 cohort studies, BP were collected either once or several times during follow-up. The identified methods in the statistical analysis were: (1) one baseline value per patient (2) last known value; (3) mean of all values; (4) modelling of all values in a two-stage approach. Applying these four different statistical methods to our cohort, the results and interpretation of the association between BP and CV were different depending on the method used. Conclusion: The BP prognostic value depends on the chosen statistical analysis method. Appropriate statistical analyses of prognostic factors in cohort studies should be considered and should enable valuable and reproducible conclusions.

scholarly journals A Comparative Evaluation of a Mesoscale Model and Atmospheric Global Circulation Model for Air Quality Simulation: A Multiscale, Multisite Evaluation

2012 ◽  
Vol 2012 ◽  
pp. 1-15 ◽  
Author(s):  
P. Goswami ◽  
J. Baruah
Keyword(s):  
High Resolution ◽  
Mesoscale Model ◽  
Large City ◽  
Circulation Model ◽  
Urban Pollution ◽  
Atmospheric Pollutants ◽  
Scale Model ◽  
Global Circulation Model ◽  
Global Circulation ◽  
Meso Scale

Concentrations of atmospheric pollutants are strongly influenced by meteorological parameters like rainfall, relative humidity and wind advection. Thus accurate specifications of the meteorological fields, and their effects on pollutants, are critical requirements for successful modelling of air pollution. In terms of their applications, pollutant concentration models can be used in different ways; in one, short term high resolution forecasts are generated to predict and manage urban pollution. Another application of dynamical pollution models is to generate outlook for a given airbasin, such as over a large city. An important question is application-specific model configuration for the meteorological simulations. While a meso-scale model provides a high-resolution configuration, a global model allows better simulation of large-sale fields through its global environment. Our objective is to comparatively evaluate a meso-scale atmospheric model (MM5) and atmospheric global circulation model (AGCM) in simulating different species of pollutants over different airbasins. In this study we consider four locations: ITO (Central Delhi), Sirifort (South Delhi), Bandra (Mumbai) and Karve Road (Pune). The results show that both the model configurations provide comparable skills in simulation of monthly and annual loads, although the skill of the meso-scale model is somewhat higher, especially at shorter time scales.

scholarly journals THOR: A NEW AND FLEXIBLE GLOBAL CIRCULATION MODEL TO EXPLORE PLANETARY ATMOSPHERES

2016 ◽  
Vol 829 (2) ◽  
pp. 115 ◽  
Author(s):  
João M. Mendonça ◽  
Simon L. Grimm ◽  
Luc Grosheintz ◽  
Kevin Heng
Keyword(s):  
Circulation Model ◽  
Planetary Atmospheres ◽  
Global Circulation Model ◽  
Global Circulation

scholarly journals True dipole wander

2018 ◽  
Vol 215 (3) ◽  
pp. 1523-1529
Author(s):  
Peter Olson ◽  
Maylis Landeau ◽  
Evan Reynolds
Keyword(s):  
Circulation Model ◽  
Global Circulation Model ◽  
Polar Wander ◽  
Global Circulation ◽  
True Polar Wander ◽  
Symmetric Pattern ◽  
Asymmetric Pattern ◽  
Heterogeneous Mantle ◽  
Geocentric Axial Dipole ◽  
Geomagnetic Dipole

SUMMARY A fundamental assumption in palaeomagnetism is that the geomagnetic field closely approximates a geocentric axial dipole in time average. Here we use numerical dynamos driven by heterogeneous core–mantle boundary heat flux from a mantle global circulation model to demonstrate how mantle convection produces true dipole wander, rotation of the geomagnetic dipole on geologic timescales. Our heterogeneous mantle-driven dynamos show a dipole rotation about a near-equatorial axis in response to the transition in lower mantle heterogeneity from a highly asymmetric pattern at the time of supercontinent Pangea to a more symmetric pattern today. This predicted dipole rotation overlaps with a palaeomagnetically inferred rotation in the opposite direction and suggests that some events previously interpreted as true polar wander also include true dipole wander.

scholarly journals The Use of Radiocarbon Measurements in Atmospheric Studies

Radiocarbon ◽  
1990 ◽  
Vol 32 (1) ◽  
pp. 37-58 ◽  
Author(s):  
M R Manning ◽  
D C Lowe ◽  
W H Melhuish ◽  
R J Sparks ◽  
Gavin Wallace ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Circulation Model ◽  
Current Data ◽  
Atmospheric Methane ◽  
Global Circulation Model ◽  
Fossil Carbon ◽  
Global Circulation ◽  
Methane Source ◽  
Clean Air ◽  
Source Current

14C measured in trace gases in clean air helps to determine the sources of such gases, their long-range transport in the atmosphere, and their exchange with other carbon cycle reservoirs. In order to separate sources, transport and exchange, it is necessary to interpret measurements using models of these processes. We present atmospheric 14CO2 measurements made in New Zealand since 1954 and at various Pacific Ocean sites for shorter periods. We analyze these for latitudinal and seasonal variation, the latter being consistent with a seasonally varying exchange rate between the stratosphere and troposphere. The observed seasonal cycle does not agree with that predicted by a zonally averaged global circulation model. We discuss recent accelerator mass spectrometry measurements of atmospheric 14CH4 and the problems involved in determining the fossil fuel methane source. Current data imply a fossil carbon contribution of ca 25%, and the major sources of uncertainty in this number are the uncertainty in the nuclear power source of 14CH4, and in the measured value for δ14C in atmospheric methane.

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