scholarly journals Verification of the Atmospheric Infrared Sounder (AIRS) and the Microwave Limb Sounder (MLS) ozone algorithms based on retrieved daytime and night-time ozone

2021 ◽  
Vol 14 (2) ◽  
pp. 1673-1687
Author(s):  
Wannan Wang ◽  
Tianhai Cheng ◽  
Ronald J. van der A ◽  
Jos de Laat ◽  
Jason E. Williams
Keyword(s):  
Spatial Scales ◽  
Retrieval Algorithm ◽  
Satellite Measurements ◽  
Night Time ◽  
Atmospheric Infrared Sounder ◽  
Dry Land ◽  
Novel Approach ◽  
Additional Support ◽  
Column Ozone

Abstract. Ozone (O3) plays a significant role in weather and climate on regional to global spatial scales. Most studies on the variability in the total column of O3 (TCO) are typically carried out using daytime data. Based on knowledge of the chemistry and transport of O3, significant deviations between daytime and night-time O3 are only expected either in the planetary boundary layer (PBL) or high in the stratosphere or mesosphere, with little effect on the TCO. Hence, we expect the daytime and night-time TCO to be very similar. However, a detailed evaluation of satellite measurements of daytime and night-time TCO is still lacking, despite the existence of long-term records of both. Thus, comparing daytime and night-time TCOs provides a novel approach to verifying the retrieval algorithms of instruments such as the Atmospheric Infrared Sounder (AIRS) and the Microwave Limb Sounder (MLS). In addition, such a comparison also helps to assess the value of night-time TCO for scientific research. Applying this verification on the AIRS and the MLS data, we identified inconsistencies in observations of O3 from both satellite instruments. For AIRS, daytime–night-time differences were found over oceans resembling cloud cover patterns and over land, mostly over dry land areas, which is likely related to infrared surface emissivity. These differences point to issues with the representation of both processes in the AIRS retrieval algorithm. For MLS, a major issue was identified with the “ascending–descending” orbit flag, used to discriminate night-time and daytime MLS measurements. Disregarding this issue, MLS day–night differences were significantly smaller than AIRS day–night differences, providing additional support for the retrieval method origin of AIRS in stratospheric column ozone (SCO) day–night differences. MLS day–night differences are dominated by the upper-stratospheric and mesospheric diurnal O3 cycle. These results provide useful information for improving infrared O3 products.

scholarly journals Verification of the AIRS and MLS ozone algorithms based on retrieved daytime and nighttime ozone

2020 ◽  
Author(s):  
Wannan Wang ◽  
Tianhai Cheng ◽  
Ronald van der A ◽  
Jos de Laat ◽  
Jason E. Williams
Keyword(s):  
Spatial Scales ◽  
Retrieval Algorithm ◽  
Surface Emissivity ◽  
Atmospheric Infrared Sounder ◽  
Retrieval Method ◽  
Dry Land ◽  
Weather And Climate ◽  
Additional Support ◽  
Infrared Instruments ◽  
Total Column

Abstract. Ozone (O3) plays a significant role in weather and climate on regional to global spatial scales. Most studies on the variability in the total column of O3 (TCO) are typically analysed using daytime data. Based on knowledge of the chemistry and transport of O3, significant deviations between daytime and nighttime O3 are only expected either in the planetary boundary layer (PBL) or high in the stratosphere or mesosphere, having little effect on the TCO. Hence, we expect the daytime and nighttime TCO to be very similar. Comparing daytime and nighttime TCOs thus provides an approach to verify the retrieval algorithms of infrared instruments like the Atmospheric InfraRed Sounder (AIRS) and the Microwave Limb Sounder (MLS). Applying this verification on the AIRS and the MLS data we identified inconsistencies in observations of O3 from both satellite instruments. For AIRS, daytime-nighttime differences were found over oceans resembling cloud cover patterns, and over land, mostly over dry land areas, likely related to infrared surface emissivity. These differences point to issues with the representation of both processes in the AIRS retrieval algorithm. For MLS, a major issue was identified with the “ascending-descending” orbit flag, used to discriminate nighttime and daytime MLS measurements. Disregarding this issue, MLS day-night differences were significantly smaller than AIRS day-night differences, providing additional support for retrieval method origin of AIRS day-night TCO differences. MLS day-night differences are dominated by the upper stratospheric and mesospheric diurnal O3 cycle. These results provide useful information for improving infrared O3 products and at the same time will allow study the day-night differences of stratospheric and mesospheric O3.

scholarly journals Trends in erythemal doses at the Polish Polar Station, Hornsund, Svalbard based on the homogenized measurements (1996–2016) and reconstructed data (1983–1995)

2018 ◽  
Vol 18 (1) ◽  
pp. 1-11 ◽  
Author(s):  
Janusz W. Krzyścin ◽  
Piotr S. Sobolewski
Keyword(s):  
Historical Data ◽  
Sunshine Duration ◽  
Satellite Measurements ◽  
Data Set ◽  
Modification Factor ◽  
Daily Sunshine ◽  
Yearly Dose ◽  
Column Ozone ◽  
Dose Variability

Abstract. Erythemal daily doses measured at the Polish Polar Station, Hornsund (77°00′ N, 15°33′ E), for the periods 1996–2001 and 2005–2016 are homogenized using yearly calibration constants derived from the comparison of observed doses for cloudless conditions with the corresponding doses calculated by radiative transfer (RT) simulations. Modeled all-sky doses are calculated by the multiplication of cloudless RT doses by the empirical cloud modification factor dependent on the daily sunshine duration. An all-sky model is built using daily erythemal doses measured in the period 2005–2006–2007. The model is verified by comparisons with the 1996–1997–1998 and 2009–2010–2011 measured data. The daily doses since 1983 (beginning of the proxy data) are reconstructed using the all-sky model with the historical data of the column ozone from satellite measurements (SBUV merged ozone data set), the snow depth (for ground albedo estimation), and the observed daily sunshine duration at the site. Trend analyses of the monthly and yearly time series comprised of the reconstructed and observed doses do not reveal a statistically significant trend in the period 1983–2016. The trends based on the observed data only (1996–2001 and 2005–2016) show declining tendency (about −1 % per year) in the monthly mean of daily erythemal doses in May and June, and in the yearly sum of daily erythemal doses. An analysis of sources of the yearly dose variability since 1983 shows that cloud cover changes are a basic driver of the long-term UV changes at the site.

scholarly journals Responses of Vertebrate Wildlife to Oil and Natural Gas Development: Patterns and Frontiers

2021 ◽  
Author(s):  
A. D. Chalfoun
Keyword(s):  
Natural Gas ◽  
Anthropogenic Activities ◽  
Spatial Scales ◽  
Habitat Type ◽  
Population Level ◽  
Low Frequencies ◽  
Natural Gas Development ◽  
The Usa ◽  
Oil And Natural Gas

Abstract Purpose of Review Anthropogenic activities can lead to the loss, fragmentation, and alteration of wildlife habitats. I reviewed the recent literature (2014–2019) focused on the responses of avian, mammalian, and herpetofaunal species to oil and natural gas development, a widespread and still-expanding land use worldwide. My primary goals were to identify any generalities in species’ responses to development and summarize remaining gaps in knowledge. To do so, I evaluated the directionality of a wide variety of responses in relation to taxon, location, development type, development metric, habitat type, and spatiotemporal aspects. Recent Findings Studies (n = 70) were restricted to the USA and Canada, and taxonomically biased towards birds and mammals. Longer studies, but not those incorporating multiple spatial scales, were more likely to detect significant responses. Negative responses of all types were present in relatively low frequencies across all taxa, locations, development types, and development metrics but were context-dependent. The directionality of responses by the same species often varied across studies or development metrics. Summary The state of knowledge about wildlife responses to oil and natural gas development has developed considerably, though many biases and gaps remain. Studies outside of North America and that focus on herpetofauna are lacking. Tests of mechanistic hypotheses for effects, long-term studies, assessment of response thresholds, and experimental designs that isolate the effects of different stimuli associated with development, remain critical. Moreover, tests of the efficacy of habitat mitigation efforts have been rare. Finally, investigations of the demographic effects of development across the full annual cycle were absent for non-game species and are critical for the estimation of population-level effects.

Patient survival after acute myocardial infarction treated with primary percutaneous coronary intervention within the left main coronary artery according to time of admission

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
R Januszek ◽  
K Bujak ◽  
M Gasior ◽  
D Dudek ◽  
S Bartus
Keyword(s):  
Myocardial Infarction ◽  
Left Main Coronary Artery ◽  
Left Main ◽  
Night Time ◽  
St Segment Elevation ◽  
Segment Elevation Myocardial Infarction ◽  
St Segment ◽  
Coronary Syndromes ◽  
Overall Mortality

Abstract Background Previously published studies assessing the time effect of primary percutaneous intervention (PCI) on long-term clinical outcomes in an overall group of patients with acute coronary syndromes has been widely investigated. It has been suggested that night-time admission may negatively influence long-term overall mortality. Patients treated within the left main coronary artery (LMCA) belong a narrow group of high-risk procedures that require an operator and a team with high skills. Purpose The aim of the presented study was to assess the relationship between the time of pPCI (day- vs. night-time) and overall mortality among patients treated due to AMI within the LMCA. Methods This observational study was performed on 443,805 patients hospitalised due to non-ST segment elevation myocardial infarction (NSTEMI) or ST-segment elevation myocardial infarction (STEMI). Patients were prospectively enrolled between January 2006 and December 2018 in the ongoing Polish Registry of Acute Coronary Syndromes (PL-ACS). From the overall group of patients, the authors selected 5,404 patients treated within the LMCA. After taking exclusion criteria into consideration, the patients were divided according to time of PCI treatment: daytime hours (7:00 a.m.-10:59 p.m.) – 2,809 patients and night-time hours (11:00 p.m. - 6.59 a.m.) – 473 patients. Results Patients treated during night-time and daytime did not differ significantly in age (70.79 [61.52–79.73] vs. 69.73 [60.8–78.82] years, p=0.13) or gender – males (67.6% vs. 67.0%, p=0.79). Patients treated during daytime presented with significantly higher rate of STEMIs (67.2% vs. 49.9%) and lower rate of NSTEMIs (32.8% vs. 50.1%) in comparison to those treated during night-time (p<0.001). The 30-day and 12-month overall mortality rates were significantly greater among patients treated during night-time hours (20.3% vs. 14.9%, p=0.003) and (31.7% vs. 26.2%, p=0.001). Kaplan-Maier survival curves confirmed this relationship (p=0.001). Multiple regression analysis did not confirm that the time of pPCI (day- vs. night-time) is significantly related to survival (hazard ratio [HR]: 1.22; 95% confidence interval [CI]: 0.96–1.55, p=0.099). However, significance was achieved for the left ventricle ejection fraction (HR: 0.95; 95% CI: 0.94–0.95, p<0.001), systolic blood pressure on admission (HR: 0.995; 95% CI: 0.991–0.998, p=0.005), age (HR: 1.04; 95% CI: 1.03–1.05, p<0.001), the use of intra-aortic balloon counterpulsation (HR: 1.04; 95% CI: 1.03–1.05, p<0.001) and diagnosed peripheral artery disease (HR: 1.55; 95% CI: 1.2–2.01, p<0.001). Conclusions The time of pPCI (day- vs. night-time) in patients with AMI and treated within the LMCA is related to the overall 30-day and 12-month survival which is poorer in those treated during the night-time. However, this relationship was not confirmed by multiple regression analysis and was not found to be significant among other stronger predictors. Funding Acknowledgement Type of funding source: None

Development of a Performance-Related Framework for Asphalt Mixture Design for the Illinois Tollway

2021 ◽  
pp. 036119812110148
Author(s):  
Behnam Jahangiri ◽  
Punyaslok Rath ◽  
Hamed Majidifard ◽  
William G. Buttlar
Keyword(s):  
Asphalt Mixture ◽  
Field Performance ◽  
Compact Tension ◽  
T Test ◽  
Novel Approach ◽  
Final Adjustment ◽  
Development And Validation ◽  
High Degree ◽  
Selection Of

Various agencies have begun to research and introduce performance-related specifications (PRS) for the design of modern asphalt paving mixtures. The focus of most recent studies has been directed toward simplified cracking test development and evaluation. In some cases, development and validation of PRS has been performed, building on these new tests, often by comparison of test values to accelerated pavement test studies and/or to limited field data. This study describes the findings of a comprehensive research project conducted at Illinois Tollway, leading to a PRS for the design of mainline and shoulder asphalt mixtures. A novel approach was developed, involving the systematic establishment of specification requirements based on: 1) selection of baseline values based on minimally acceptable field performance thresholds; 2) elevation of thresholds to account for differences between short-term lab aging and expected long-term field aging; 3) further elevation of thresholds to account for variability in lab testing, plus variability in the testing of field cores; and 4) final adjustment and rounding of thresholds based on a consensus process. After a thorough evaluation of different candidate cracking tests in the course of the project, the Disk-shaped Compact Tension—DC(T)—test was chosen to be retained in the Illinois Tollway PRS and to be presented in this study for the design of crack-resistant mixtures. The DC(T) test was selected because of its high degree of correlation with field results and its excellent repeatability. Tailored Hamburg rut depth and stripping inflection point thresholds were also established for mainline and shoulder mixes.

A Novel Approach Towards Cementing Design Achieved Significant Improvement in Long Term Zonal Isolation

2019 ◽  
Author(s):  
Ala Suleiman ◽  
Bashar Hilal ◽  
Phalgun Paila ◽  
Sahir Abdelhadi ◽  
Khalid Alwahedi ◽  
...  
Keyword(s):  
Novel Approach ◽  
Zonal Isolation

scholarly journals The Passive Microwave Neural Network Precipitation Retrieval Algorithm for Climate Applications (PNPR-CLIM): Design and Verification

2021 ◽  
Vol 13 (9) ◽  
pp. 1701
Author(s):  
Leonardo Bagaglini ◽  
Paolo Sanò ◽  
Daniele Casella ◽  
Elsa Cattani ◽  
Giulia Panegrossi
Keyword(s):  
Neural Network ◽  
Passive Microwave ◽  
Retrieval Algorithm ◽  
Climate Data ◽  
High Quality ◽  
Data Record ◽  
Global Precipitation ◽  
Climate Data Record

This paper describes the Passive microwave Neural network Precipitation Retrieval algorithm for climate applications (PNPR-CLIM), developed with funding from the Copernicus Climate Change Service (C3S), implemented by ECMWF on behalf of the European Union. The algorithm has been designed and developed to exploit the two cross-track scanning microwave radiometers, AMSU-B and MHS, towards the creation of a long-term (2000–2017) global precipitation climate data record (CDR) for the ECMWF Climate Data Store (CDS). The algorithm has been trained on an observational dataset built from one year of MHS and GPM-CO Dual-frequency Precipitation Radar (DPR) coincident observations. The dataset includes the Fundamental Climate Data Record (FCDR) of AMSU-B and MHS brightness temperatures, provided by the Fidelity and Uncertainty in Climate data records from Earth Observation (FIDUCEO) project, and the DPR-based surface precipitation rate estimates used as reference. The combined use of high quality, calibrated and harmonized long-term input data (provided by the FIDUCEO microwave brightness temperature Fundamental Climate Data Record) with the exploitation of the potential of neural networks (ability to learn and generalize) has made it possible to limit the use of ancillary model-derived environmental variables, thus reducing the model uncertainties’ influence on the PNPR-CLIM, which could compromise the accuracy of the estimates. The PNPR-CLIM estimated precipitation distribution is in good agreement with independent DPR-based estimates. A multiscale assessment of the algorithm’s performance is presented against high quality regional ground-based radar products and global precipitation datasets. The regional and global three-year (2015–2017) verification analysis shows that, despite the simplicity of the algorithm in terms of input variables and processing performance, the quality of PNPR-CLIM outperforms NASA GPROF in terms of rainfall detection, while in terms of rainfall quantification they are comparable. The global analysis evidences weaknesses at higher latitudes and in the winter at mid latitudes, mainly linked to the poorer quality of the precipitation retrieval in cold/dry conditions.

Stabilisation of Hg1-xCdxTe:Hg1-yCdyTex ≠ y) Heterointerfaces and Applications in Infra Red Devices

1990 ◽  
Vol 216 ◽  
Author(s):  
Paul A. Clifton ◽  
Paul D. Brown
Keyword(s):  
Barrier Layer ◽  
Epitaxial Layers ◽  
Long Wavelength ◽  
Long Term Stability ◽  
Novel Approach ◽  
Infra Red ◽  
Passivation Layers ◽  
Cdte Buffer ◽  
Initial Results

ABSTRACTThe interface between Hg1-xCdxTe(0 ≦ x ≦ 1) and Hg1-yCdyTe(0 ≦ y ≦ 1) epitaxial layers of different composition (x ≠ y) is unstable with regard to the intermixing of the Hg and Cd cations within the Group II sublattice. This phenomenon may give rise to long-term stability problems in HgTe-(Hg,Cd)Te superlattices and composition grading between (Hg,Cd)Te absorber layers and CdTe buffer or passivation layers in epitaxial infra red detectors. In this paper, a novel approach to the inhibition of interdiffusion in these systems is discussed. This involves the growth of an intervening ZnTe barrier layer at the heterointerface between two (Hg,Cd)Te layers. Initial results are presented which indicate the effectiveness of this technique in reducing interdiffusion in an experimental heterostructure grown by MOVPE. Some possible applications in a variety of HgTe-based long wavelength devices are discussed.

Protected Areas: offering security to whom, when and where?

2016 ◽  
Vol 43 (2) ◽  
pp. 172-180 ◽  
Author(s):  
ALICE B. KELLY ◽  
A. CLARE GUPTA
Keyword(s):  
Protected Areas ◽  
Environmental Conditions ◽  
Protected Area ◽  
Spatial Scales ◽  
Local Population ◽  
Well Being ◽  
Economic Context ◽  
Term Management ◽  
Over Time

SUMMARYThis study considers the issue of security in the context of protected areas in Cameroon and Botswana. Though the literature on issues of security and well-being in relation to protected areas is extensive, there has been less discussion of how and in what ways these impacts and relationships can change over time, vary with space and differ across spatial scales. Looking at two very different historical trajectories, this study considers the heterogeneity of the security landscapes created by Waza and Chobe protected areas over time and space. This study finds that conservation measures that various subsets of the local population once considered to be ‘bad’ (e.g. violent, exclusionary protected area creation) may be construed as ‘good’ at different historical moments and geographical areas. Similarly, complacency or resignation to the presence of a park can be reversed by changing environmental conditions. Changes in the ways security (material and otherwise) has fluctuated within these two protected areas has implications for the long-term management and funding strategies of newly created and already existing protected areas today. This study suggests that parks must be adaptively managed not only for changing ecological conditions, but also for shifts in a protected area's social, political and economic context.

ABPM Comparison of the Anti-Hypertensive Profiles of Telmisartan and Enalapril in Patients with Mild-to-Moderate Essential Hypertension

2002 ◽  
Vol 30 (6) ◽  
pp. 543-552 ◽  
Author(s):  
J Amerena ◽  
S Pappas ◽  
J-P Ouellet ◽  
L Williams ◽  
D O'Shaughnessy
Keyword(s):  
Blood Pressure ◽  
Essential Hypertension ◽  
Blood Pressure Monitoring ◽  
Study Drug ◽  
Pressure Control ◽  
Moderate Essential Hypertension ◽  
Open Label ◽  
Night Time ◽  
Once Daily

In this multicentre, prospective, randomized, open-label, blinded-endpoint (PROBE) study, the efficacy of 12 weeks' treatment with once-daily telmisartan 40–80 mg and enalapril 10–20 mg was evaluated using ambulatory blood pressure monitoring (ABPM) in 522 patients with mild-to-moderate essential hypertension. Patients were titrated to the higher dose of study drug at week 6 if mean seated diastolic blood pressure (DBP) was ≥ 90 mmHg. The primary endpoint was the change from baseline in ambulatory DBP in the last 6 h of the 24-h dosing interval after 12 weeks' treatment. Telmisartan and enalapril produced similar reductions from baseline in DBP and systolic blood pressure (SBP) over all ABPM periods evaluated (last 6 h, 24-h, daytime and night-time). Telmisartan produced a significantly greater reduction in mean seated trough DBP, measured unblinded with an automated ABPM device in the clinic, amounting to a difference of −2.02 mmHg ( P < 0.01). A significantly greater proportion of patients achieved a seated diastolic response with telmisartan than enalapril (59% versus 50%; P < 0.05), also measured with the same ABPM device. Both treatments were well tolerated. Compared with telmisartan, enalapril was associated with a higher incidence of cough (8.9% versus 0.8%) and hypotension (3.9% versus 1.1%). Therefore, telmisartan may provide better long-term compliance and, consequently, better blood pressure control than enalapril.

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