Understanding our capabilities in observing and modelling Coronal Mass Ejections

2020 ◽  
Author(s):  
Christine Verbeke ◽  
Marilena Mierla ◽  
M. Leila Mays ◽  
Christina Kay ◽  
Mateja Dumbovic ◽  
...  
Keyword(s):  
Coronal Mass Ejections ◽  
Large Scale ◽  
Remote Sensing Data ◽  
Large Set ◽  
Common Procedure ◽  
Propagation Models ◽  
Weather Events ◽  
Prediction Time ◽  
First Results ◽  
The Impact

<p>Coronal Mass Ejections (CMEs) are large-scale eruptions of plasma and magnetic fields from the Sun. They are considered to be the main drivers of strong space weather events at Earth. Multiple models have been developed over the past decades to be able to predict the propagation of CMEs and their arrival time at Earth. Such models require input from observations, which can be used to fit the CME to an appropriate structure.</p><p>When determining input parameters for CME propagation models, it is common procedure to derive kinematic parameters from remote-sensing data. The resulting parameters can be used as inputs for the CME propagation models to obtain an arrival prediction time of the CME f.e. at Earth. However, when fitting the CME structure to obtain the needed parameters for simulations, different geometric structures and also different parts of the CME structure can be fitted. These aspects, together with the fact that 3D reconstructions strongly depend on the subjectivity and judgement of the scientist performing them, may lead to uncertainties in the fitted parameters. Up to now, no large study has tried to map these uncertainties and to evaluate how they affect the modelling of CMEs.  </p><p>Fitting a large set of CMEs within a selected period of time, we aim to investigate the uncertainties in the CME fittings in detail. Each event is fitted multiple times by different scientists. We discuss statistics on uncertainties of the fittings. We also present some first results of the impact of these uncertainties on CME propagation modelling.</p><p>Acknowledgements: This work has been partly supported by the International Space Science Institute (ISSI) in the framework of International Team 480 entitled: Understanding Our Capabilities In Observing And Modelling Coronal Mass Ejections'.</p>

scholarly journals Retrieving Forest Canopy Elements Clumping Index Using ICESat GLAS Lidar Data

2021 ◽  
Vol 13 (5) ◽  
pp. 948
Author(s):  
Lei Cui ◽  
Ziti Jiao ◽  
Kaiguang Zhao ◽  
Mei Sun ◽  
Yadong Dong ◽  
...  
Keyword(s):  
Large Scale ◽  
Forest Canopy ◽  
Remote Sensing Data ◽  
Alternative Methods ◽  
High Signal ◽  
Laser Altimeter ◽  
Waveform Data ◽  
Forest Park ◽  
Clumping Index ◽  
The Impact

Clumping index (CI) is a canopy structural variable important for modeling the terrestrial biosphere, but its retrieval from remote sensing data remains one of the least reliable. The majority of regional or global CI products available so far were generated from multiangle optical reflectance data. However, these reflectance-based estimates have well-known limitations, such as the mere use of a linear relationship between the normalized difference hotspot and darkspot (NDHD) and CI, uncertainties in bidirectional reflectance distribution function (BRDF) models used to calculate the NDHD, and coarse spatial resolutions (e.g., hundreds of meters to several kilometers). To remedy these limitations and develop alternative methods for large-scale CI mapping, here we explored the use of spaceborne lidar—the Geoscience Laser Altimeter System (GLAS)—and proposed a semi-physical algorithm to estimate CI at the footprint level. Our algorithm was formulated to leverage the full vertical canopy profile information of the GLAS full-waveform data; it converted raw waveforms to forest canopy gap distributions and gap fractions of random canopies, which was used to estimate CI based on the radiative transfer theory and a revised Beer–Lambert model. We tested our algorithm over two areas in China—the Saihanba National Forest Park and Heilongjiang Province—and assessed its relative accuracies against field-measured CI and MODIS CI products. We found that reliable estimation of CI was possible only for GLAS waveforms with high signal-to-noise ratios (e.g., >65) and at gentle slopes (e.g., <12°). Our GLAS-based CI estimates for high-quality waveforms compared well to field-based CI (i.e., R2 = 0.72, RMSE = 0.07, and bias = 0.02), but they showed less correlation to MODIS CI (e.g., R2 = 0.26, RMSE = 0.12, and bias = 0.04). The difference highlights the impact of the scale effect in conducting comparisons of products with huge differences resolution. Overall, our analyses represent the first attempt to use spaceborne lidar to retrieve high-resolution forest CI and our algorithm holds promise for mapping CI globally.

scholarly journals Cap rates and risk: a spatial analysis of commercial real estate

2018 ◽  
Vol 35 (1) ◽  
pp. 25-43
Author(s):  
Florian Unbehaun ◽  
Franz Fuerst
Keyword(s):  
Real Estate ◽  
Risk Perceptions ◽  
Large Scale ◽  
Risk Premia ◽  
Real Estate Market ◽  
Commercial Real Estate ◽  
Data Series ◽  
Large Set ◽  
Content Type ◽  
The Impact

Purpose This study aims to assess the impact of location on capitalization rates and risk premia. Design/methodology/approach Using a transaction-based data series for the five largest office markets in Germany from 2005 to 2015, regression analysis is performed to account for a large set of asset-level drivers such as location, age and size and time-varying macro-level drivers. Findings Location is found to be a key determinant of cap rates and risk premia. CBD locations are found to attract lower cap rates and lower risk premia in three of the five largest markets in Germany. Interestingly, this effect is not found in the non-CBD locations of these markets, suggesting that the lower perceived risk associated with these large markets is restricted to a relatively small area within these markets that are reputed to be safe investments. Research limitations/implications The findings imply that investors view properties in peripheral urban locations as imperfect substitutes for CBD properties. Further analysis also shows that these risk premia are not uniformly applied across real estate asset types. The CBD risk effect is particularly pronounced for office and retail assets, apparently considered “prime” investments within the central locations. Originality/value This is one of the first empirical studies of the risk implications of peripheral commercial real estate locations. It is also one of the first large-scale cap rate analyses of the German commercial real estate market. The results demonstrate that risk perceptions of investors have a distinct spatial dimension.

scholarly journals Informal nature experience on the school playground

2015 ◽  
Vol 2 (1) ◽  
pp. 18-25 ◽  
Author(s):  
Andreas Raith
Keyword(s):  
Primary Schools ◽  
Large Scale ◽  
School Teacher ◽  
Meta Analysis ◽  
Educational Institutions ◽  
Primary School Teacher ◽  
School Playgrounds ◽  
First Results ◽  
The Impact ◽  
Nature Experience

Abstract In Germany, all-day care and all-day schooling are currently increasing on a large-scale. The extended time children spend in educational institutions could potentially result in limited access to nature experience for children. On the other hand, it could equally create opportunities for informal nature experience if school playgrounds have a specific nature-oriented design. This article is written from the perspective of a primary school teacher and presents the findings of a meta-analysis which looks at the impact nature experience has on the development of children. Furthermore, the first results of a research study on green playgrounds in primary schools is discussed. The results so far seem to indicate that green school playgrounds have the potential of providing nature experience particularly for primary students

The Impact of Disasters on Japan’s Inbound Tourism Demand

2014 ◽  
Vol 9 (sp) ◽  
pp. 699-708 ◽  
Author(s):  
Lihui Wu ◽  
◽  
Haruo Hayashi ◽  
Keyword(s):  
Large Scale ◽  
Moving Average ◽  
Geographical Location ◽  
Extreme Weather ◽  
Extreme Weather Events ◽  
Tourism Demand ◽  
Intervention Models ◽  
Weather Events ◽  
Inbound Tourism ◽  
The Impact

The purpose of this study is to explore the impact of disasters on international tourism demand for Japan by applying Autoregressive Integrated Moving Average (ARIMA) intervention models that focus on evaluating change patterns and the duration of effects by observing variations in parameters. Japan suffered a variety of disasters, especially natural disasters due to its geographical location, so we have divided these disasters into three types: geological disasters, extreme weather events and “others” such as terrorist attacks, infectious diseases, and economic crises. Based on the principle of preparing for the worst, we selected 4 cases for each disaster type, for 12 in all. Results suggest that (1) large-scale disasters such as great earthquakes impacted negatively on inbound tourism demand for Japan; (2) not all disasters resulted in an abrupt drop in inbound tourist arrivals, extreme weather events, for example, did not decrease inbound tourism demand significantly; (3) impact caused by disasters was temporary.

scholarly journals Role of Soil Moisture Feedback in the Development of Extreme Summer Drought and Flood in the United States

2016 ◽  
Vol 17 (8) ◽  
pp. 2191-2207 ◽  
Author(s):  
Roop Saini ◽  
Guiling Wang ◽  
Jeremy S. Pal
Keyword(s):  
United States ◽  
Soil Moisture ◽  
Large Scale ◽  
Climate Model ◽  
The United States ◽  
Summer Drought ◽  
Large Set ◽  
Drought And Flood ◽  
The Impact ◽  
Soil Moisture Feedback

Abstract This study tackles the contribution of soil moisture feedback to the development of extreme summer precipitation anomalies over the conterminous United States using a regional climate model. The model performs well in reproducing both the mean climate and extremes associated with drought and flood. A large set of experiments using the model are conducted that involve swapped initial soil moisture between flood and drought years using the 1988 and 2012 droughts and 1993 flood as examples. The starting time of these experiments includes 1 May (late spring) and 1 June (early summer). For all three years, the impact of 1 May soil moisture swapping is much weaker than the 1 June soil moisture swapping. In 1988 and 2012, replacing the 1 June soil moisture with that from 1993 reduces both the spatial extent and the severity of the simulated summer drought and heat. The impact is especially strong in 2012. In 1993, however, replacing the 1 June soil moisture with that from 1988 has little impact on precipitation. The contribution of soil moisture feedback to summer extremes is larger in 2012 than in 1988 and 1993. This may be because of the presence of strong anomalies in large-scale forcing in 1988 and 1993 that prohibit or favor precipitation, and the lack of such in 2012. This study demonstrates how the contribution of land–atmosphere feedback to the development of seasonal climate anomalies may vary from year to year and highlights its importance in the 2012 drought.

scholarly journals Mixed dark matter: matter power spectrum and halo mass function

2021 ◽  
Vol 2021 (12) ◽  
pp. 044
Author(s):  
G. Parimbelli ◽  
G. Scelfo ◽  
S.K. Giri ◽  
A. Schneider ◽  
M. Archidiacono ◽  
...  
Keyword(s):  
Dark Matter ◽  
Power Spectrum ◽  
Large Scale ◽  
Cosmological Parameters ◽  
Mass Function ◽  
Large Set ◽  
Cluster Number ◽  
Matter Power Spectrum ◽  
Wide Range ◽  
The Impact

Abstract We investigate and quantify the impact of mixed (cold and warm) dark matter models on large-scale structure observables. In this scenario, dark matter comes in two phases, a cold one (CDM) and a warm one (WDM): the presence of the latter causes a suppression in the matter power spectrum which is allowed by current constraints and may be detected in present-day and upcoming surveys. We run a large set of N-body simulations in order to build an efficient and accurate emulator to predict the aforementioned suppression with percent precision over a wide range of values for the WDM mass, Mwdm, and its fraction with respect to the totality of dark matter, fwdm. The suppression in the matter power spectrum is found to be independent of changes in the cosmological parameters at the 2% level for k≲ 10 h/Mpc and z≤ 3.5. In the same ranges, by applying a baryonification procedure on both ΛCDM and CWDM simulations to account for the effect of feedback, we find a similar level of agreement between the two scenarios. We examine the impact that such suppression has on weak lensing and angular galaxy clustering power spectra. Finally, we discuss the impact of mixed dark matter on the shape of the halo mass function and which analytical prescription yields the best agreement with simulations. We provide the reader with an application to galaxy cluster number counts.

Stability of intact chorionic gonadotropin (hCG) in serum, liquid whole blood, and dried whole-blood filter-paper spots: impact on screening for Down syndrome by measurement of free beta-hCG subunit

1993 ◽  
Vol 39 (6) ◽  
pp. 1064-1068 ◽  
Author(s):  
K Spencer ◽  
J N Macri ◽  
P Carpenter ◽  
R Anderson ◽  
D A Krantz
Keyword(s):  
Down Syndrome ◽  
Chorionic Gonadotropin ◽  
Filter Paper ◽  
Whole Blood ◽  
Large Scale ◽  
Maternal Serum ◽  
Large Set ◽  
Beta Hcg ◽  
In Transit ◽  
The Impact

Abstract The use of multiple maternal serum biochemical markers in screening for Down syndrome is gaining worldwide acceptance. We sought to study the impact of the potential instability of intact human chorionic gonadotropin (hCG) on free beta-hCG subunit, a marker that has recently been used successfully in such screening. We found that, in practice, any changes in free beta-hCG due to the instability of intact hCG do not inhibit the effectiveness of free beta-hCG as a marker for Down syndrome. This was proven by controlled laboratory experiments at various stress temperatures, freeze-thaw studies, and analysis of a large set of screening data with particular reference to time in transit for individual samples. Data from controlled dissociation studies demonstrate that any apparent increase in free beta-hCG due to the instability of intact hCG cannot be attributed simply to the dissociation of intact hCG. Finally, for large-scale mass population screening in areas of the world where transport delays, safety concerns, and high temperatures preclude the shipment of liquid whole blood, dried whole-blood spots in filter paper provide a suitable delivery system with many advantages.

scholarly journals Insights into the Noncoding RNome of Nitrogen-Fixing Endosymbiotic α-Proteobacteria

2013 ◽  
Vol 26 (2) ◽  
pp. 160-167 ◽  
Author(s):  
José I. Jiménez-Zurdo ◽  
Claudio Valverde ◽  
Anke Becker
Keyword(s):  
Gene Expression ◽  
Large Scale ◽  
Regulation Of Gene Expression ◽  
Living Environment ◽  
Large Set ◽  
Nitrogen Fixing ◽  
Symbiotic Interaction ◽  
Animal Pathogens ◽  
Wide Range ◽  
The Impact

Symbiotic chronic infection of legumes by rhizobia involves transition of invading bacteria from a free-living environment in soil to an intracellular state as differentiated nitrogen-fixing bacteroids within the nodules elicited in the host plant. The adaptive flexibility demanded by this complex lifestyle is likely facilitated by the large set of regulatory proteins encoded by rhizobial genomes. However, proteins are not the only relevant players in the regulation of gene expression in bacteria. Large-scale high-throughput analysis of prokaryotic genomes is evidencing the expression of an unexpected plethora of small untranslated transcripts (sRNAs) with housekeeping or regulatory roles. sRNAs mostly act in response to environmental cues as post-transcriptional regulators of gene expression through protein-assisted base-pairing interactions with target mRNAs. Riboregulation contributes to fine-tune a wide range of bacterial processes which, in intracellular animal pathogens, largely compromise virulence traits. Here, we summarize the incipient knowledge about the noncoding RNome structure of nitrogen-fixing endosymbiotic bacteria as inferred from genome-wide searches for sRNA genes in the alfalfa partner Sinorhizobium meliloti and further comparative genomics analysis. The biology of relevant S. meliloti RNA chaperones (e.g., Hfq) is also reviewed as a first global indicator of the impact of riboregulation in the establishment of the symbiotic interaction.

scholarly journals Establishing an operational system for assessment and forecasting the impact of extreme weather events on crop production

MAUSAM ◽  
2021 ◽  
Vol 67 (1) ◽  
pp. 289-296
Author(s):  
SHIBENDU S. RAY ◽  
SURESH K. SINGH ◽  
NEETU . ◽  
S. MAMATHA
Keyword(s):  
Remote Sensing ◽  
Case Studies ◽  
Crop Production ◽  
Large Scale ◽  
Extreme Weather ◽  
Extreme Weather Events ◽  
Wheat Crop ◽  
Production Forecasting ◽  
Weather Events ◽  
The Impact

Crop production forecasting is essential for various economic policy and decision making. There is a very successful operational programme in the country, called FASAL, which uses multiple approaches for pre-harvest production forecasting.  With the increase in the frequency of extreme events and their large-scale impact on agriculture, there is a strong need to use remote sensing technology for assessing the impact.  Various works have been done in this direction. This article provides three such case studies, where remote sensing along with other data have been used for assessment of flood inundation of rice crop post Phailin cyclone, period operational district/sub-district level drought assessment and understanding the impact of recent hailstorm/unseasonal rainfall on wheat crop. The case studies highlight the great scope of remote sensing data for assessment of the impact of extreme weather events on crop production.

Sign in / Sign up

Export Citation Format

Share Document