| 1. |
- Menkveld, Albert J., et al.
(författare)
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Nonstandard Errors
- 2024
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Ingår i: JOURNAL OF FINANCE. - : Wiley-Blackwell. - 0022-1082 .- 1540-6261. ; 79:3, s. 2339-2390
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Tidskriftsartikel (refereegranskat)abstract
- In statistics, samples are drawn from a population in a data-generating process (DGP). Standard errors measure the uncertainty in estimates of population parameters. In science, evidence is generated to test hypotheses in an evidence-generating process (EGP). We claim that EGP variation across researchers adds uncertainty-nonstandard errors (NSEs). We study NSEs by letting 164 teams test the same hypotheses on the same data. NSEs turn out to be sizable, but smaller for more reproducible or higher rated research. Adding peer-review stages reduces NSEs. We further find that this type of uncertainty is underestimated by participants.
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| 2. |
- Rapp, Markus, et al.
(författare)
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Rocket-borne in situ measurements of meteor smoke : Charging properties and implications for seasonal variation
- 2010
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Ingår i: Journal of Geophysical Research. - 0148-0227 .- 2156-2202. ; 115, s. D00I16-
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Tidskriftsartikel (refereegranskat)abstract
- Rocket-borne observations of meteoric smoke particles (MSPs) are presented from three campaigns at polar latitudes (69 degrees N) in September 2006, and in the summers of 2007 and 2008. MSPs are detected using a novel technique based on photoelectron emission from the particles after stimulation by UV photons emitted by a xenon flashlamp. Resulting photoelectron currents are shown to be proportional to particle volume density. September results match model predictions qualitatively at altitudes from 65 to 85 km while measurements at higher altitudes are contaminated by photoelectrons from NO and O-2((1)Delta(g)). Contamination below this altitude can be excluded based on concurrent satellite observations. The observations show a large variability from flight to flight. Part of this variability can be attributed to differences in the charging of MSPs during day and night. Finally we find that MSP volume density in summer can exceed that during September. Analyzing model simulations of the global transport and microphysics of these particles, we show that our observations are in agreement with the model predictions, even though number densities of particles with radii >1 nm, which have long been thought to be suitable condensation nuclei for mesospheric ice particles, show the opposite behavior. It is shown that this discrepancy is caused by the fact that even larger particles (similar to 3 nm) dominate the volume density and that transport affects these different particle sizes in different ways. These results reinforce previous model findings according to which seasonal MSP variability is mainly driven by the global circulation and corresponding transport.
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| 3. |
- Enell, Carl-Fredrik, et al.
(författare)
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The Hotel Payload 2 campaign : Overview of NO, O and electron density measurements in the upper mesosphere and lower thermosphere
- 2011
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Ingår i: Journal of Atmospheric and Solar-Terrestrial Physics. - : Elsevier BV. - 1364-6826 .- 1879-1824. ; 73:14-15, s. 2228-2236
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Tidskriftsartikel (refereegranskat)abstract
- The ALOMAR eARI Hotel Payload 2 (HotPay 2) rocket campaign took place at Andoya Rocket Range, Norway, in January 2008. The rocket was launched on January 31, 2008 at 19:14 UT, when auroral activity appeared after a long geomagnetically quiet period. In this paper we present an overview of the HotPay 2 measurements of upper mesospheric and lower thermospheric (UMLT) electron, atomic oxygen (O) and nitric oxide (NO) densities. [O] and [NO] were retrieved from a set of three photometers, Night-Time Emissions from the Mesosphere and Ionosphere (NEMI). Faraday rotation receivers on the rocket and the EISCAT UHF incoherent scatter radar provided simultaneous electron density profiles, whereas the ALOMAR Na lidar and meteor radar measured the temperature profile and wind. The aurora was also observed with ground-based imagers. The retrieved oxygen number density profile has a maximum at 89 km, some 10 km lower than expected from earlier measurements and modelled profiles based on climatological averages (such as the MSIS model), and the retrieved NO densities are also lower than the expected. Satellite measurements indicate that subsidence over the winter pole controlled the densities. Quantitative chemistry model results based on climatological average atmospheric density and temperature profiles were, therefore, not in good agreement with the measured profiles. The Hotel Payload 2 measurements thus confirm the importance of downward transport from the thermosphere into the winter polar vortex.
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| 4. |
- Strelnikov, Boris, et al.
(författare)
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Spatial and temporal variability in MLT turbulence inferred from in situ and ground-based observations during the WADIS-1 sounding rocket campaign
- 2017
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Ingår i: Annales Geophysicae. - : Copernicus GmbH. - 0992-7689 .- 1432-0576. ; 35:3, s. 547-565
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Tidskriftsartikel (refereegranskat)abstract
- In summer 2013 the WADIS-1 sounding rocket campaign was conducted at the Andoya Space Center (ACS) in northern Norway (69 degrees N, 16 degrees E). Among other things, it addressed the question of the variability in mesosphere/lower thermosphere (MLT) turbulence, both in time and space. A unique feature of the WADIS project was multi-point turbulence sounding applying different measurement techniques including rocket-borne ionization gauges, VHF MAARSY radar, and VHF EISCAT radar near Tromso. This allowed for horizontal variability to be observed in the turbulence field in the MLT at scales from a few to 100 km. We found that the turbulence dissipation rate, epsilon varied in space in a wavelike manner both horizontally and in the vertical direction. This wavelike modulation reveals the same vertical wavelengths as those seen in gravity waves. We also found that the vertical mean value of radar observations of epsilon agrees reasonably with rocket-borne measurements. In this way defined value reveals clear tidal modulation and results in variation by up to 2 orders of magnitude with periods of 24 h. The value also shows 12 h and shorter (1 to a few hours) modulations resulting in one decade of variation in magnitude. The 24 h modulation appeared to be in phase with tidal change of horizontal wind observed by SAURA-MF radar. Such wavelike and, in particular, tidal modulation of the turbulence dissipation field in the MLT region inferred from our analysis is a new finding of this work.
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| 5. |
- Strelnikova, Irina, et al.
(författare)
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Measurements of meteor smoke particles during the ECOMA-2006 campaign. 2 : Results
- 2009
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Ingår i: Journal of Atmospheric and Solar-Terrestrial Physics. - : Elsevier BV. - 1364-6826 .- 1879-1824. ; 71:3-4, s. 486-496
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Tidskriftsartikel (refereegranskat)abstract
- The first sounding rocket of the European ECOMA-project (ECOMA, Existence and Charge state Of Meteoric smoke particles in the middle Atmosphere) was launched on 8 September 2006. Measurements with a new particle detector described in the companion paper by Rapp and Strelnikova [2008. Measurements of meteor smoke particles during the ECOMA-2006 campaign: 1. Particle detection by active photoionization. Journal of Atmospheric and Solar-Terrestrial Physics, this issue, doi:10.1016/j.jastp.2008.06.002] clearly showed meteor smoke particle (MSP) signatures in both data channels. The data channels measure particles directly impacting on the detector electrode and photoelectrons from the particles actively created using ionization by the UV-photons of a xenon-flashlamp. Measured photoelectron currents resemble model expectations of the shape of the MSP layer almost perfectly, whereas derived number densities in the altitude range 60–90 km are larger than model results by about a factor of 5. Given the large uncertainties inherent to both model and the analysis of our measurements (e.g., the composition of the particles is not known and must be assumed) we consider this a satisfactory agreement and proof that MSPs do extend throughout the entire mesosphere as predicted by models. The measurements of direct particle impacts revealed a confined layer of negative charge between 80 and 90 km. This limited altitude range, however, is quantitatively shown to be the consequence of the aerodynamics of the rocket flight and does not have any geophysical origin. Measured charge signatures are consistent with expectations of particle charging given our own measurements of the background ionization. Unfortunately, however, a contamination of these measurements from triboelectric charging cannot be excluded at this stage
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