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Zimmerman, Katie. "Observations on Observation." Endeavour 35, no. 4 (December 2011): 125. http://dx.doi.org/10.1016/j.endeavour.2011.09.001.
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Shulman, Stanford T. "Observations on Otitic Observation." Pediatric Annals 33, no. 12 (December 1, 2004): 797. http://dx.doi.org/10.3928/0090-4481-20041201-03.
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Kharasch, Evan D. "Observations and Observational Research." Anesthesiology 131, no. 1 (July 1, 2019): 1–4. http://dx.doi.org/10.1097/aln.0000000000002818.
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Robyn Bluhm. "Some Observations on “Observational” Research." Perspectives in Biology and Medicine 52, no. 2 (2009): 252–63. http://dx.doi.org/10.1353/pbm.0.0076.
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Brankart, Jean-Michel, Clément Ubelmann, Charles-Emmanuel Testut, Emmanuel Cosme, Pierre Brasseur, and Jacques Verron. "Efficient Parameterization of the Observation Error Covariance Matrix for Square Root or Ensemble Kalman Filters: Application to Ocean Altimetry." Monthly Weather Review 137, no. 6 (June 1, 2009): 1908–27. http://dx.doi.org/10.1175/2008mwr2693.1.
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Abstract In the Kalman filter standard algorithm, the computational complexity of the observational update is proportional to the cube of the number y of observations (leading behavior for large y). In realistic atmospheric or oceanic applications, involving an increasing quantity of available observations, this often leads to a prohibitive cost and to the necessity of simplifying the problem by aggregating or dropping observations. If the filter error covariance matrices are in square root form, as in square root or ensemble Kalman filters, the standard algorithm can be transformed to be linear in y, providing that the observation error covariance matrix is diagonal. This is a significant drawback of this transformed algorithm and often leads to an assumption of uncorrelated observation errors for the sake of numerical efficiency. In this paper, it is shown that the linearity of the transformed algorithm in y can be preserved for other forms of the observation error covariance matrix. In particular, quite general correlation structures (with analytic asymptotic expressions) can be simulated simply by augmenting the observation vector with differences of the original observations, such as their discrete gradients. Errors in ocean altimetric observations are spatially correlated, as for instance orbit or atmospheric errors along the satellite track. Adequately parameterizing these correlations can directly improve the quality of observational updates and the accuracy of the associated error estimates. In this paper, the example of the North Brazil Current circulation is used to demonstrate the importance of this effect, which is especially significant in that region of moderate ratio between signal amplitude and observation noise, and to show that the efficient parameterization that is proposed for the observation error correlations is appropriate to take it into account. Adding explicit gradient observations also receives a physical justification. This parameterization is thus proved to be useful to ocean data assimilation systems that are based on square root or ensemble Kalman filters, as soon as the number of observations becomes penalizing, and if a sophisticated parameterization of the observation error correlations is required.
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West, Brady T., and Frauke Kreuter. "Strategies for Increasing the Accuracy of Interviewer Observations of Respondent Features." Methodology 14, no. 1 (January 1, 2018): 16–29. http://dx.doi.org/10.1027/1614-2241/a000142.
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Abstract. Because survey response rates are consistently declining worldwide, survey researchers strive to obtain as much auxiliary information on sampled units as possible. Surveys using in-person interviewing often request that interviewers collect observations on key features of all sampled units, given that interviewers are the eyes and ears of the survey organization. Unfortunately, these observations are prone to error, which decreases the effectiveness of nonresponse adjustments based on the observations. No studies have investigated the strategies being used by interviewers tasked with making these observations, or examined whether certain strategies improve observation accuracy. This study is the first to examine the associations of observational strategies used by survey interviewers with the accuracy of observations collected by those interviewers. A qualitative analysis followed by multilevel models of observation accuracy shows that focusing on relevant correlates of the feature being observed and considering a diversity of cues are associated with increased observation accuracy.
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Tarida, Elga, Andria Catri Tamsin, and Zulfikarni Zulfikarni. "STRUKTUR DAN CIRI KEBAHASAAN TEKS LAPORAN HASIL OBSERVASI SISWA KELAS VII SMP NEGERI 12 SOLOK SELATAN." Pendidikan Bahasa Indonesia 9, no. 1 (February 20, 2020): 50. http://dx.doi.org/10.24036/108263-019883.
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ABSTRACT This study aims to (1) describe the structure of the report text observation of the work of class VII SMP Negeri 12 Solok Selatan (2) illustrates the linguistic characteristics of the observation report text by class VII SMP Negeri 12 Solok Selatan. The results of this study are as follows. First, in writing the report text of observations of Grade VII students of class VII SMP Negeri 12 Solok Selatan, they have used the three text structures of the observation report results. The structure of the report's observational text is a general definition, section description, and description of benefits. This is evident from the 20 observational report texts that have been analyzed throughout the observation report text of class VII SMP Negeri 12 Solok Selatan complete using general definitions, section descriptions, and benefits descriptions. Second, in writing the report text of observations generally in class VII SMP Negeri 12 Solok Selatan have used the four text structures of the observation report. The Fourth linguistic characteristics of the text of the observation report are repetition, pronoun, conjunction, and description sentences. This is evident from the 20 text reports on observations that have been analyzed, there are 16 text reports on observations that are complete using the linguistic characteristics of repetition, pronouns, conjunctions, and sentence definitions. Kata Kunci: Struktur Teks, Ciri Kebahasaan, dan Teks Laporan Hasil Observasi
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Battistelli, E. S., E. Carretti, P. de Bernardis, and S. Masi. "Large Radio Telescopes for Anomalous Microwave Emission Observations." Advances in Astronomy 2012 (2012): 1–8. http://dx.doi.org/10.1155/2012/607384.
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We discuss in this paper the problem of the Anomalous Microwave Emission (AME) in the light of ongoing or future observations to be performed with the largest fully steerable radio telescope in the world. High angular resolution observations of the AME will enable astronomers to drastically improve the knowledge of the AME mechanisms as well as the interplay between the different constituents of the interstellar medium in our galaxy. Extragalactic observations of the AME have started as well, and high resolution is even more important in this kind of observations. When cross-correlating with IR-dust emission, high angular resolution is also of fundamental importance in order to obtain unbiased results. The choice of the observational frequency is also of key importance in continuum observation. We calculate a merit function that accounts for the signal-to-noise ratio (SNR) in AME observation given the current state-of-the-art knowledge and technology. We also include in our merit functions the frequency dependence in the case of multifrequency observations. We briefly mention and compare the performance of four of the largest radiotelescopes in the world and hope the observational programs in each of them will be as intense as possible.
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Nikolov, A. S. "An Application of Personal Computers in Astronomy Education." International Astronomical Union Colloquium 105 (1990): 177–78. http://dx.doi.org/10.1017/s0252921100086668.
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Observations play an important role in the process of teaching astronomical knowledge. Practical observations of astronomical phenomena lead to analysis and explanation based on natural laws and so form the basis of cognitive processes in the education. Evidently the observations are an integral part of acquiring astronomical knowledge. Giving up observations, no matter what the reasons, is equivalent to losing quality in the educational process. It decreases the possible influence over the personal development of pupils and students. At the same time, observation and observational results are important for success in education.Carefully planned observational time has a substantial influence on cognitive and educational processes. It leads to considerably more active participation in astronomy lectures.
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Jung, Byoung-Joo, Hyun Mee Kim, Thomas Auligné, Xin Zhang, Xiaoyan Zhang, and Xiang-Yu Huang. "Adjoint-Derived Observation Impact Using WRF in the Western North Pacific." Monthly Weather Review 141, no. 11 (October 25, 2013): 4080–97. http://dx.doi.org/10.1175/mwr-d-12-00197.1.
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Abstract An increasing number of observations have contributed to the performance of numerical weather prediction systems. Accordingly, it is important to evaluate the impact of these observations on forecast accuracy. While the observing system experiment (OSE) requires considerable computational resources, the adjoint-derived method can evaluate the impact of all observational components at a lower cost. In this study, the effect of observations on forecasts is evaluated by the adjoint-derived method using the Weather Research and Forecasting Model, its adjoint model, and a corresponding three-dimensional variational data assimilation system in East Asia and the western North Pacific for the 2008 typhoon season. Radiance observations had the greatest total impact on forecasts, but conventional wind observations had the greatest impact per observation. For each observation type, the total impact was greatest for radiosonde and each Advanced Microwave Sounding Unit (AMSU)-A satellite, followed by surface synoptic observation from a land station (SYNOP), Quick Scatterometer (QuikSCAT), atmospheric motion vector (AMV) wind from a geostationary satellite (GEOAMV), and aviation routine weather reports (METARs). The fraction of beneficial observations was approximately 60%–70%, which is higher than that reported in previous studies. For several analyses of Typhoons Sinlaku (200813) and Jangmi (200815), dropsonde soundings taken near the typhoon had similar or greater observation impacts than routine radiosonde soundings. The sensitivity to the error covariance parameter indicates that reducing (increasing) observation (background) error covariance helps to reduce forecast error in the current analysis framework. The observation impact from OSEs is qualitatively similar to that from the adjoint method for major observation types. This study confirms that radiosonde observations provide primary information on the atmospheric state as in situ observations and that satellite radiances are an essential component of atmospheric observation systems.
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Pessoa, Osvaldo. "A Causal-Pluralist Metatheory of Observation." Open Philosophy 2, no. 1 (December 13, 2019): 657–67. http://dx.doi.org/10.1515/opphil-2019-0050.
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AbstractAn extended definition of “observation” is developed in order to account for the usage in the physical sciences and in neuropsychology. An observation is initially defined as a perception that has a focus of attention and is guided by theoretical considerations. Since the focus may change, one adopts a pluralist position according to which the object of perception may involve any stage of the causal chain that leads to perception, such as the source of light or sound, the obstructions, the medium or even the receptor. The “neutral” observations of the empiricists are seen as involving only low-level or medium-level theorization. Examples are examined, such as a lunar eclipse, the rainbow, and observations mediated by instruments, whose “artifacts” are considered observations of the instrument itself. One also defines null-effect observations. Observations of photographs and drawings may be considered either the observation of a printed sheet of paper or the observation of the pictured object or people. This causal-pluralist metatheory of observation also accepts that one may “observe light”, observe the retina, and observe parts of the brain which are outside the region of the “sensorium”. Illusions and hallucinations are analyzed within this “observational materialism”, which considers that qualia are self-observations of the brain. Criticisms that the approach is too wide in scope are analyzed in the conclusion.
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Branham, Richard L. "Techniques for dealing with discordant observations." Symposium - International Astronomical Union 114 (1986): 229–31. http://dx.doi.org/10.1017/s0074180900148247.
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To test any theory such as theories of motion–Newtonian or relativistic–of solar system objects, one must compare the predictions of theory with observation. But discordant observations habitually plague the reducer of astronomical data. To alleviate the baleful effects, particularly harmful when the observations are reduced by the method of least squares, of discordant data investigators almost invariably reject observations whose corresponding (0-C)'s or post-solution residuals exceed a cutoff. But techniques that are insensitive to the assumption that the observational errors are normally distributed, called robust estimation in the literature, have also been developed.
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Holman, Matthew J., and Matthew J. Payne. "OBSERVATIONAL CONSTRAINTS ON PLANET NINE:CASSINIRANGE OBSERVATIONS." Astronomical Journal 152, no. 4 (September 29, 2016): 94. http://dx.doi.org/10.3847/0004-6256/152/4/94.
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Zhu, Shujun, Bin Wang, Lin Zhang, Juanjuan Liu, Yongzhu Liu, Jiandong Gong, Shiming Xu, et al. "Assimilating AMSU-A Radiance Observations with an Ensemble Four-Dimensional Variational (En4DVar) Hybrid Data Assimilation System." Remote Sensing 15, no. 14 (July 10, 2023): 3476. http://dx.doi.org/10.3390/rs15143476.
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Many ensemble-based data assimilation (DA) methods use observation space localization to mitigate the sampling errors due to the insufficient ensemble members. Observation space localization is simpler and more timesaving than model space localization in implementation, but more difficult to directly assimilate satellite radiance observations, a kind of non-local observations. The vertical locations of radiance observations are undetermined and the transmission of observational information is thereby obstructed. To determine the vertical coordinates of radiance observations, a weighted average hypsometry is proposed. Using this hypsometry, AMSU-A radiance observations are directly assimilated with an ensemble four-dimensional variational (En4DVar) DA system. It consists of a four-dimensional ensemble-variational (4DEnVar) system providing ensemble covariance and a 4DVar system. Observing system simulation experiments show that the hypsometry alleviates the degradations in the late period of medium-range forecast in the Northern Extratropics that occur in the traditional peak-based hypsometry. It obviously improves the analysis qualities and forecast skills of the En4DVar system and its two components, especially in the Southern Extratropics, when incorporating AMSU-A radiance observations. The improvement in the En4DVar-initialized forecast is comparable to that in the 4DVar-initialized forecast in the Southern Extratropics and Tropics. It indicates that a proper hypsometry enables efficient extraction of useful information from AMSU-A radiance observations by 4DEnVar with observation space localization. Therefore, the 4DEnVar provides high-quality ensemble covariances for En4DVar.
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Mosser, B. "Giant planets seismology." Symposium - International Astronomical Union 181 (1997): 251–64. http://dx.doi.org/10.1017/s0074180900061192.
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The giant planets Jupiter and Saturn belong to the interesting category of possible goals for remote seismic analysis. Their first seismic observations and their analysis were attempted in 1987 and 1991 respectively, under Philippe Delache's initiative. The theoretical analysis of giant planets seismology reveals the strong signature of the dense planetary core and the tiny one of the hydrogen plasma phase transition. The asymptotic formalism makes possible to obtain pertinent information for the observation of planetary oscillations and for their analysis. Specific observational techniques were developed to detect the seismic signature of giant planets. However, the first observations (Schmider et al. 1991, Mosser et al. 1993) of Jovian oscillations remain tentative. Even if the Jovian origin of the signal is beyond doubt, the interpretation in terms of Jovian global modes remains speculative. The collision of comet SL9 onto Jupiter provided an unexpected and unique opportunity to search for oscillations excited by the cometary impacts (Mosser et al. 1996). Seismic observations of Saturn remain negative so far. Therefore, this review focuses on Jupiter. Finally, the almost 10-years long experience of seismic observations of Jupiter and Saturn has not yet provided new constraints for planetary interior models. However, guidelines for future observational projects dedicated to Jovian seismology can be drawn. The different techniques of observation are compared, and observational requirements are precisely described.
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Stuckey, Heather L., Jennifer L. Kraschnewski, Michelle Miller-Day, Kimberly Palm, Caroline Larosa, and Christopher Sciamanna. "“Weighing” Two Qualitative Methods." Field Methods 26, no. 4 (April 8, 2014): 343–61. http://dx.doi.org/10.1177/1525822x14526543.
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Two primary forms of qualitative data collection in the health and social sciences include self-report interviews and direct observations. This study compared these two methods in the context of weight management for people who had varying degrees of success with weight loss ( n = 20). We asked general habits of eating as well as barriers to weight loss and maintaining a healthy diet. Video-recorded observations (20 minutes) followed audio-recorded interviews (45 minutes). Data were organized into four primary sections: (1) confirmatory data, where the interviews and observations held similar information; (2) discrepancies between what was reported in the interview and what was observed in the home; (3) new information that was unique to the observation and was not mentioned during the interview; and (4) clarification of data collected in the interview and observation. In general, the observations contained more confirmatory data for participants who had been successful at weight control than those who had not. The majority of observational data were emergent, which led to the discovery of new data of which we were unaware prior to the observations.
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Fyfe, Nicholas R. "Observations on observations." Journal of Geography in Higher Education 16, no. 2 (January 1992): 127–33. http://dx.doi.org/10.1080/03098269208709185.
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Pickstone, John V. "Observations on observations." British Journal for the History of Science 45, no. 4 (December 2012): 671–75. http://dx.doi.org/10.1017/s0007087412001367.
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Balsamo, G., J.-F. Mahfouf, S. Bélair, and G. Deblonde. "A Land Data Assimilation System for Soil Moisture and Temperature: An Information Content Study." Journal of Hydrometeorology 8, no. 6 (December 1, 2007): 1225–42. http://dx.doi.org/10.1175/2007jhm819.1.
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Abstract A Canadian Land Data Assimilation System (CaLDAS) for the analysis of land surface prognostic variables is designed and implemented at the Meteorological Service of Canada for the initialization of numerical weather prediction and climate models. The assimilation of different data sources for the production of daily soil moisture and temperature analyses is investigated in a set of observing system simulation experiments over North America. A simplified variational technique is adapted to accommodate different observation types at their appropriate time in a 24-h time window. The screen-level observations of temperature and relative humidity, from conventional synoptic surface observations (SYNOP)/aviation routine weather report (METAR)/surface aviation observation (SA) reports, are considered together with presently available satellite observations provided by the Aqua satellite (microwave C-band), Geostationary Operational Environmental Satellite (GOES) [infrared (IR)], and observations available in the future by the Soil Moisture and Ocean Salinity (SMOS) satellite mission (microwave L-band). The aim of these experiments is to assess the information content brought by each observation type in the land surface analysis. The observation systems are simulated according to their spatial coverage, temporal availability, and nominal or expected errors. The results show that the observable with the largest dynamical response to perturbations of the control variable carries the greatest information content into the analysis. The observational error and the observation frequency counterbalance this feature in the analysis. If one considers a single observation both for soil moisture and soil temperature analysis, then satellite measurements (L-band, C-band, and IR in decreasing order of importance) are the primary source of information. When observation availability is considered and the highest temporal frequency of screen-level observations is used (1 h), a large amount of information is extracted from SYNOP-like reports. The screen-level observations are shown to provide valuable soil moisture information mainly during the daytime, while during nighttime these observations (and particularly screen-level temperature) are mostly useful for the soil temperature analysis. The results are presented with perspectives for future operational developments and preliminary assimilation experiments are performed with hourly screen-level observations.
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Peng, Q. Y., N. V. Emelyanov, L. Zhou, and W. R. Gu. "Astrometry from mutual event and small-separation CCD imaging." Proceedings of the International Astronomical Union 3, S248 (October 2007): 114–15. http://dx.doi.org/10.1017/s1743921308018796.
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AbstractIn order to determine precisely positions of the Galilean satellites of Jupiter, it is useful that shortly before and/or after photometric observations of a mutual event, normal CCD imaging observation is also performed for the two small-separation satellites. Experimental observations showed that the two observational types, on the whole, could derive mean (O-C) s with very good internal and external agreement (about 15–20 mas).
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Donato, Anthony A., Yoon Soo Park, David L. George, Alan Schwartz, and Rachel Yudkowsky. "Validity and Feasibility of the Minicard Direct Observation Tool in 1 Training Program." Journal of Graduate Medical Education 7, no. 2 (June 1, 2015): 225–29. http://dx.doi.org/10.4300/jgme-d-14-00532.1.
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Abstract Background Availability of reliable, valid, and feasible workplace-based assessment (WBA) tools is important to allow faculty to make important and complex judgments about resident competence. The Minicard is a WBA direct observation tool designed to provide formative feedback while supporting critical competency decisions. Objective The purpose of this study was to collect validity and feasibility evidence for use of the Minicard for formative assessment of internal medicine residents. Methods We conducted a retrospective cohort analysis of Minicard observations from 2005–2011 in 1 institution to obtain validity evidence, including content (settings, observation rates, independent raters); response process (rating distributions across the scale and ratings by month in the program); consequences (qualitative assessment of action plans); and feasibility (time to collect observations). Results Eighty faculty observers recorded 3715 observations of 73 residents in the inpatient ward (43%), clinic (39%), intensive care (15%), and emergency department (3%) settings. Internal medicine residents averaged 28 (SD = 8.4) observations per year from 9 (SD = 4.1) independent observers. Minicards had an average of 5 (SD = 5.1) discrete recorded observations per card. Rating distributions covered the entire rating scale, and increased significantly over the time in training. Half of the observations included action plans with action-oriented feedback, 11% had observational feedback, 9% had minimal feedback, and 30% had no recorded plan. Observations averaged 15.6 (SD = 9.5) minutes. Conclusions Validity evidence for the Minicard direct observation tool demonstrates its ability to facilitate identification of “struggling” residents and provide feedback, supporting its use for the formative assessment of internal medicine residents.
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Gummesson, Evert. "Access to reality: observations on observational methods." Qualitative Market Research: An International Journal 10, no. 2 (April 10, 2007): 130–34. http://dx.doi.org/10.1108/13522750710740808.
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Satterfield, Elizabeth, Daniel Hodyss, David D. Kuhl, and Craig H. Bishop. "Investigating the Use of Ensemble Variance to Predict Observation Error of Representation." Monthly Weather Review 145, no. 2 (February 2017): 653–67. http://dx.doi.org/10.1175/mwr-d-16-0299.1.
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Data assimilation schemes combine observational data with a short-term model forecast to produce an analysis. However, many characteristics of the atmospheric states described by the observations and the model differ. Observations often measure a higher-resolution state than coarse-resolution model grids can describe. Hence, the observations may measure aspects of gradients or unresolved eddies that are poorly resolved by the filtered version of reality represented by the model. This inconsistency, known as observation representation error, must be accounted for in data assimilation schemes. In this paper the ability of the ensemble to predict the variance of the observation error of representation is explored, arguing that the portion of representation error being detected by the ensemble variance is that portion correlated to the smoothed features that the coarse-resolution forecast model is able to predict. This predictive relationship is explored using differences between model states and their spectrally truncated form, as well as commonly used statistical methods to estimate observation error variances. It is demonstrated that the ensemble variance is a useful predictor of the observation error variance of representation and that it could be used to account for flow dependence in the observation error covariance matrix.
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Kutoyants, Yury A., and Vladimir Spokoiny. "Optimal choice of observation window for Poisson observations." Statistics & Probability Letters 44, no. 3 (September 1999): 291–98. http://dx.doi.org/10.1016/s0167-7152(99)00020-6.
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Nola, Robert. "Some observations on a Popperian experiment concerning observation." Journal for General Philosophy of Science 21, no. 2 (September 1990): 329–46. http://dx.doi.org/10.1007/bf01801042.
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Wartenburger, R., S. Brönnimann, and A. Stickler. "Observation errors in early historical upper-air observations." Journal of Geophysical Research: Atmospheres 118, no. 21 (November 11, 2013): 12,012–12,028. http://dx.doi.org/10.1002/2013jd020156.
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Cooper, Elizabeth S., Sarah L. Dance, Javier García-Pintado, Nancy K. Nichols, and Polly J. Smith. "Observation operators for assimilation of satellite observations in fluvial inundation forecasting." Hydrology and Earth System Sciences 23, no. 6 (June 5, 2019): 2541–59. http://dx.doi.org/10.5194/hess-23-2541-2019.
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Abstract. Images from satellite-based synthetic aperture radar (SAR) instruments contain large amounts of information about the position of floodwater during a river flood event. This observational information typically covers a large spatial area but is only relevant for a short time if water levels are changing rapidly. Data assimilation allows us to combine valuable SAR-derived observed information with continuous predictions from a computational hydrodynamic model and thus to produce a better forecast than using the model alone. In order to use observations in this way, a suitable observation operator is required. In this paper we show that different types of observation operators can produce very different corrections to predicted water levels; this impacts the quality of the forecast produced. We discuss the physical mechanisms by which different observation operators update modelled water levels and introduce a novel observation operator for inundation forecasting. The performance of the new operator is compared in synthetic experiments with that of two more conventional approaches. The conventional approaches both use observations of water levels derived from SAR to correct model predictions. Our new operator is instead designed to use backscatter values from SAR instruments as observations; such an approach has not been used before in an ensemble Kalman filtering framework. Direct use of backscatter observations opens up the possibility of using more information from each SAR image and could potentially speed up the time taken to produce observations needed to update model predictions. We compare the strengths and weaknesses of the three different approaches with reference to the physical mechanisms with which each of the observation operators allow data assimilation to update water levels in synthetic twin experiments in an idealised domain.
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Kim, J., H. M. Kim, and C. H. Cho. "Influence of CO<sub>2</sub> observations on the optimized CO<sub>2</sub> flux in an ensemble Kalman filter." Atmospheric Chemistry and Physics 14, no. 24 (December 19, 2014): 13515–30. http://dx.doi.org/10.5194/acp-14-13515-2014.
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Abstract. In this study, the effect of CO2 observations on an analysis of surface CO2 flux was calculated using an influence matrix in the CarbonTracker, which is an inverse modeling system for estimating surface CO2 flux based on an ensemble Kalman filter. The influence matrix represents a sensitivity of the analysis to observations. The experimental period was from January 2000 to December 2009. The diagonal element of the influence matrix (i.e., analysis sensitivity) is globally 4.8% on average, which implies that the analysis extracts 4.8% of the information from the observations and 95.2% from the background each assimilation cycle. Because the surface CO2 flux in each week is optimized by 5 weeks of observations, the cumulative impact over 5 weeks is 19.1%, much greater than 4.8%. The analysis sensitivity is inversely proportional to the number of observations used in the assimilation, which is distinctly apparent in continuous observation categories with a sufficient number of observations. The time series of the globally averaged analysis sensitivities shows seasonal variations, with greater sensitivities in summer and lower sensitivities in winter, which is attributed to the surface CO2 flux uncertainty. The time-averaged analysis sensitivities in the Northern Hemisphere are greater than those in the tropics and the Southern Hemisphere. The trace of the influence matrix (i.e., information content) is a measure of the total information extracted from the observations. The information content indicates an imbalance between the observation coverage in North America and that in other regions. Approximately half of the total observational information is provided by continuous observations, mainly from North America, which indicates that continuous observations are the most informative and that comprehensive coverage of additional observations in other regions is necessary to estimate the surface CO2 flux in these areas as accurately as in North America.
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Mahmood, Rezaul, Megan Schargorodski, Eric Rappin, Melissa Griffin, Patrick Collins, Kevin Knupp, Andrew Quilligan, Ryan Wade, Kevin Cary, and Stuart Foster. "The Total Solar Eclipse of 2017: Meteorological Observations from a Statewide Mesonet and Atmospheric Profiling Systems." Bulletin of the American Meteorological Society 101, no. 6 (June 1, 2020): E720—E737. http://dx.doi.org/10.1175/bams-d-19-0051.1.
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Abstract A total solar eclipse traversed the continental United States on 21 August 2017. It was the first such event in 99 years and provided a rare opportunity to observe the atmospheric response from a variety of instrumented observational platforms. This paper discusses the high-quality observations collected by the Kentucky Mesonet (www.kymesonet.org), a research-grade meteorological and climatological observation network consisting of 72 stations and measuring air temperature, precipitation, relative humidity, solar radiation, wind speed, and wind direction. The network samples the atmosphere, for most variables, every 3 s and then calculates and records observations every 5 min. During the total solar eclipse, these observations were complemented by observations collected from three atmospheric profiling systems positioned in the path of the eclipse and operated by the University of Alabama in Huntsville (UAH). Observational data demonstrate that solar radiation at the surface dropped from >800 to 0 W m‒2, the air temperature decreased by about 4.5°C, and, most interestingly, a land-breeze–sea-breeze-type wind developed. In addition, due to the high density of observations, the network recorded a detailed representation of the spatial variation of surface meteorology. The UAH profiling system captured collapse and reformation of the planetary boundary layer and related changes during the total solar eclipse.
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Weijs, Steven V., and Nick van de Giesen. "Accounting for Observational Uncertainty in Forecast Verification: An Information-Theoretical View on Forecasts, Observations, and Truth." Monthly Weather Review 139, no. 7 (July 1, 2011): 2156–62. http://dx.doi.org/10.1175/2011mwr3573.1.
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Abstract Recently, an information-theoretical decomposition of Kullback–Leibler divergence into uncertainty, reliability, and resolution was introduced. In this article, this decomposition is generalized to the case where the observation is uncertain. Along with a modified decomposition of the divergence score, a second measure, the cross-entropy score, is presented, which measures the estimated information loss with respect to the truth instead of relative to the uncertain observations. The difference between the two scores is equal to the average observational uncertainty and vanishes when observations are assumed to be perfect. Not acknowledging for observation uncertainty can lead to both overestimation and underestimation of forecast skill, depending on the nature of the noise process.
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Eradze, Maka, María Jesús Rodríguez-Triana, and Mart Laanpere. "A Conversation between Learning Design and Classroom Observations: A Systematic Literature Review." Education Sciences 9, no. 2 (April 26, 2019): 91. http://dx.doi.org/10.3390/educsci9020091.
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Learning Design, as a field of research, provides practitioners with guidelines towards more effective teaching and learning. In parallel, observational methods (manual or automated) have been used in the classroom to reflect on and refine teaching and learning, often in combination with other data sources (such as surveys and interviews). Despite the fact that both Learning Design and classroom observation aim to support teaching and learning practices (respectively a priori or a posteriori), they are not often aligned. To better understand the potential synergies between these two strategies, this paper reports on a systematic literature review based on 24 works that connect learning design and classroom observations. The review analyses the purposes of the studies, the stakeholders involved, the methodological aspects of the studies, and how design and observations are connected. This review reveals the need for computer-interpretable documented designs; the lack of reported systematic approaches and technological support to connect the (multimodal) observations with the corresponding learning designs; and, the predominance of human-mediated observations of the physical space, whose applicability and scalability are limited by the human resources available. The adoption of ICT tools to support the design process would contribute to extracting the context of the observations and the pedagogical framework for the analysis. Moreover, extending the traditional manual observations with Multimodal Learning Analytic techniques, would not only reduce the observation burden but also support the systematic data collection, integration, and analysis, especially in semi-structured and structured studies.
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Carrasco, V. M. S., M. C. Gallego, and J. M. Vaquero. "Number of sunspot groups from the Galileo–Scheiner controversy revisited." Monthly Notices of the Royal Astronomical Society 496, no. 2 (June 30, 2020): 2482–92. http://dx.doi.org/10.1093/mnras/staa1633.
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ABSTRACT We revise the sunspot observations made by Galileo Galilei and Christoph Scheiner in the context of their controversy regarding the nature of sunspots. Those of their sunspot records not included in the current sunspot group database, used as a basis to calculate the sunspot group number, are analysed. Within the documentary sources consulted in this work, we can highlight the sunspot observations by Scheiner included in the letters sent under the pseudonym Apelles to Marcus Welser and the first sunspot observations made by Galileo, which can be consulted in Le opere di Galileo Galilei. These sunspot observations would extend the temporal coverage for these two observers and fill some gaps in the current group database in the earliest period, where the data available are sparse. Moreover, we have detected changes in the quality of the sunspot drawings made by Galileo and Scheiner in their observation series, affecting the number of groups recorded by the two observers. We also compare these records with sunspot observations made by other astronomers of that time. According to this comparison and regarding the same observation days, Scheiner was generally the astronomer who reported more sunspot groups, while Harriot, Cigoli and Galileo recorded a similar number of groups. We conclude that these differences are mainly because of the observational methods used by the observers.
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Cluzet, Bertrand, Matthieu Lafaysse, Emmanuel Cosme, Clément Albergel, Louis-François Meunier, and Marie Dumont. "CrocO_v1.0: a particle filter to assimilate snowpack observations in a spatialised framework." Geoscientific Model Development 14, no. 3 (March 19, 2021): 1595–614. http://dx.doi.org/10.5194/gmd-14-1595-2021.
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Abstract. Monitoring the evolution of snowpack properties in mountainous areas is crucial for avalanche hazard forecasting and water resources management. In situ and remotely sensed observations provide precious information on the state of the snowpack but usually offer limited spatio-temporal coverage of bulk or surface variables only. In particular, visible–near-infrared (Vis–NIR) reflectance observations can provide information about the snowpack surface properties but are limited by terrain shading and clouds. Snowpack modelling enables the estimation of any physical variable virtually anywhere, but it is affected by large errors and uncertainties. Data assimilation offers a way to combine both sources of information and to propagate information from observed areas to non-observed areas. Here, we present CrocO (Crocus-Observations), an ensemble data assimilation system able to ingest any snowpack observation (applied as a first step to the height of snow (HS) and Vis–NIR reflectances) in a spatialised geometry. CrocO uses an ensemble of snowpack simulations to represent modelling uncertainties and a particle filter (PF) to reduce them. The PF is prone to collapse when assimilating too many observations. Two variants of the PF were specifically implemented to ensure that observational information is propagated in space while tackling this issue. The global algorithm ingests all available observations with an iterative inflation of observation errors, while the klocal algorithm is a localised approach performing a selection of the observations to assimilate based on background correlation patterns. Feasibility testing experiments are carried out in an identical twin experiment setup, with synthetic observations of HS and Vis–NIR reflectances available in only one-sixth of the simulation domain. Results show that compared against runs without assimilation, analyses exhibit an average improvement of the snow water equivalent continuous rank probability score (CRPS) of 60 % when assimilating HS with a 40-member ensemble and an average 20 % CRPS improvement when assimilating reflectance with a 160-member ensemble. Significant improvements are also obtained outside the observation domain. These promising results open a possibility for the assimilation of real observations of reflectance or of any snowpack observations in a spatialised context.
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McGwin, Gerald, and Cynthia Owsley. "The Complexity of Integrating Observations Into Observational Research." JAMA Ophthalmology 139, no. 9 (September 1, 2021): 1005. http://dx.doi.org/10.1001/jamaophthalmol.2021.2633.
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Huang, Jing, Huadong Guo, Guang Liu, Hairong Wang, Yu Deng, and Runbo Dong. "Observational angular analysis of Moon-based Earth observations." International Journal of Remote Sensing 43, no. 6 (March 19, 2022): 2315–33. http://dx.doi.org/10.1080/01431161.2022.2058894.
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Kahnert, Michael, and Emma Andersson. "How much information do extinction and backscattering measurements contain about the chemical composition of atmospheric aerosol?" Atmospheric Chemistry and Physics 17, no. 5 (March 9, 2017): 3423–44. http://dx.doi.org/10.5194/acp-17-3423-2017.
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Abstract. We theoretically and numerically investigate the problem of assimilating multiwavelength lidar observations of extinction and backscattering coefficients of aerosols into a chemical transport model. More specifically, we consider the inverse problem of determining the chemical composition of aerosols from these observations. The main questions are how much information the observations contain to determine the particles' chemical composition, and how one can optimize a chemical data assimilation system to make maximum use of the available information. We first quantify the information content of the measurements by computing the singular values of the scaled observation operator. From the singular values we can compute the number of signal degrees of freedom, Ns, and the reduction in Shannon entropy, H. As expected, the information content as expressed by either Ns or H grows as one increases the number of observational parameters and/or wavelengths. However, the information content is strongly sensitive to the observation error. The larger the observation error variance, the lower the growth rate of Ns or H with increasing number of observations. The right singular vectors of the scaled observation operator can be employed to transform the model variables into a new basis in which the components of the state vector can be partitioned into signal-related and noise-related components. We incorporate these results in a chemical data assimilation algorithm by introducing weak constraints that restrict the assimilation algorithm to acting on the signal-related model variables only. This ensures that the information contained in the measurements is fully exploited, but not overused. Numerical tests show that the constrained data assimilation algorithm provides a solution to the inverse problem that is considerably less noisy than the corresponding unconstrained algorithm. This suggests that the restriction of the algorithm to the signal-related model variables suppresses the assimilation of noise in the observations.
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Han, X., X. Li, H. J. Hendricks Franssen, H. Vereecken, and C. Montzka. "Spatial horizontal correlation characteristics in the land data assimilation of soil moisture." Hydrology and Earth System Sciences 16, no. 5 (May 10, 2012): 1349–63. http://dx.doi.org/10.5194/hess-16-1349-2012.
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Abstract. Remote sensing images deliver important information about soil moisture, but often cover only part of an area, for example due to the presence of clouds or vegetation. This paper examines the potential of incorporating the spatial horizontal correlation characteristics of surface soil moisture observations in land data assimilation in order to obtain improved estimates of soil moisture at uncovered grid cells (i.e. grid cells without observations). Observing system simulation experiments were carried out to assimilate the synthetic surface soil moisture observations into the Community Land Model for the Babaohe River Basin in northwestern China. The estimation of soil moisture at the uncovered grid cells was improved when information about surrounding observations and their spatial correlation structure was included. Including an increasing number of observations for covered and uncovered grid cells in the assimilation procedure led to a better prediction of soil moisture with an upper limit of five observations. A further increase of the number of observations did not further improve the results for this specific case. High observational coverage resulted in a better assimilation performance, depending also on the spatial distribution of observation data. In summary, the spatial horizontal correlation structure of soil moisture was found to be helpful for improving the surface soil moisture data characterization, especially for uncovered grid cells.
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Kim, J., H. M. Kim, and C. H. Cho. "Influence of CO<sub>2</sub> observations on the optimized CO<sub>2</sub> flux in an ensemble Kalman filter." Atmospheric Chemistry and Physics Discussions 14, no. 9 (May 26, 2014): 13561–602. http://dx.doi.org/10.5194/acpd-14-13561-2014.
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Abstract. Various data assimilation schemes have been applied in studies on atmospheric CO2 inversion. An influence matrix based on the linear statistical analysis scheme can diagnose the impact of individual observations on a particular analysis. In this study, to estimate the effect of CO2 observations on an analysis of surface CO2 flux, both the analysis sensitivity and the information content were calculated using the influence matrix in the CarbonTracker, which is an inverse modeling system for estimating surface CO2 flux based on an ensemble Kalman filter. The experimental period was from January 2000 to December 2009. The global average self-sensitivity is 4.8%, which implies that the analysis extracts 4.8% of the information from the observations and 95.2% from the background each assimilation cycle. Because the surface CO2 flux in each week is optimized by five weeks of observations, the cumulative impact over five weeks would be greater than 4.8%. The analysis sensitivity is inversely proportional to the number of observations used in the assimilation, which is distinctly apparent in continuous observation categories with a sufficient number of observations. The time series of the globally averaged analysis sensitivities shows seasonal variations, with greater sensitivities in summer and lower sensitivities in winter, which is attributed to the surface CO2 flux uncertainty. The time-averaged analysis sensitivities in the Northern Hemisphere are greater than those in the Tropics and the Southern Hemisphere. The information content indicates an imbalance between the observation coverage in North America and that in other regions. Approximately half of the total observational information is provided by continuous observations, mainly from North America, which indicates that continuous observations are the most informative and that comprehensive coverage of additional observations in other regions is necessary to estimate the surface CO2 flux in these areas as accurately as in North America. In addition, the uncertainty of the surface CO2 flux in Asia, where observations are sparse, is reduced by assimilating five weeks of observations as opposed to one week of observations in North America, which indicates that a longer assimilation window with a lag is necessary to optimize the surface CO2 flux in Asia.
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van Nifterik, Gustaaf. "Observations on the Legal Observations." Grotiana 40, no. 1 (December 12, 2019): 1–6. http://dx.doi.org/10.1163/18760759-04000007.
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In the years 1777–1778 four volumes were published under the title Legal Observations on Several Dark and Until Now Unverified Sections of the Introduction. The volumes were composed by a society of young legal practitioners from The Hague (Netherlands), the most famous among them being Joannes van der Linden. By then Grotius’s Introduction to the Jurisprudence of Holland was still the cornerstone of the law of Holland and around the year 1800 it would become the fundament for attempts to codify this law. Today the Legal Observations can function as entrance to the historical sources of the law of Holland as described by Grotius and developed further after publication of his Introduction.
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Ruggiero, Giovanni Abdelnur, Emmanuel Cosme, Jean-Michel Brankart, Julien Le Sommer, and Clement Ubelmann. "An Efficient Way to Account for Observation Error Correlations in the Assimilation of Data from the Future SWOT High-Resolution Altimeter Mission." Journal of Atmospheric and Oceanic Technology 33, no. 12 (December 2016): 2755–68. http://dx.doi.org/10.1175/jtech-d-16-0048.1.
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AbstractMost data assimilation algorithms require the inverse of the covariance matrix of the observation errors. In practical applications, the cost of computing this inverse matrix with spatially correlated observation errors is prohibitive. Common practices are therefore to subsample or combine the observations so that the errors of the assimilated observations can be considered uncorrelated. As a consequence, a large fraction of the available observational information is not used in practical applications. In this study, a method is developed to account for the correlations of the errors that will be present in the wide-swath sea surface height measurements, for example, the Surface Water and Ocean Topography (SWOT) mission. It basically consists of the transformation of the observation vector so that the inverse of the corresponding covariance matrix can be replaced by a diagonal matrix, thus allowing to genuinely take into account errors that are spatially correlated in physical space. Numerical experiments of ensemble Kalman filter analysis of SWOT-like observations are conducted with three different observation error covariance matrices. Results suggest that the proposed method provides an effective way to account for error correlations in the assimilation of the future SWOT data. The transformation of the observation vector proposed herein yields both a significant reduction of the root-mean-square errors and a good consistency between the filter analysis error statistics and the true error statistics.
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Lada, Elizabeth A., and João F. Alves. "Observations of Star Formation." Symposium - International Astronomical Union 221 (2004): 3–15. http://dx.doi.org/10.1017/s0074180900241405.
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Star formation is a continuous ongoing process occurring over the lifetime of our Galaxy and the universe. However understanding how stars form from their pre-natal clouds of gas and dust remains a mystery. During the last two decades we have made remarkable progress toward unraveling this mystery mainly due to advances in observational technology especially at infrared and millimeter wavelengths which allow direct observation of the sites of star birth. Such observations suggest that embedded clusters may be the fundamental units of star formation in molecular clouds. Low star formation efficiency and rapid gas dispersal make these clusters disperse to provide the field star population. Consequently embedded clusters provide important laboratories for investigating fundamental issues of star formation within our Galaxy.
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Farah, Ashraf. "Assessment study of static-PPP convergence behaviour using gps, glonass and mixed gps/glonass observations." Artificial Satellites 49, no. 1 (March 1, 2014): 55–61. http://dx.doi.org/10.2478/arsa-2014-0005.
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Abstract Precise Point Positioning (PPP) has been used for the last decade as a cost-effective alternative for the ordinary DGPS-Differential GPS with an estimated precision sufficient for many applications. PPP requires handling different types of errors using proper models. PPP precision varies with the use of observations from different satellite systems (GPS, GLONASS and mixed GPS/GLONASS) and the duration of observations. This research presents an evaluation study for the variability of Static-PPP precision based on different observation types (GPS, GLONASS and mixed observations) and observation duration. It can be concluded that Static-PPP solution using mixed observations is offering similar accuracy as the one using GPS-only observations and saving 15 minutes observation time. For 30 minutes of observation duration, mixed observations offers improvement percentages of 14%, 26% and 25% for latitude, longitude and height respectively.
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Madaus, Luke E., and Clifford F. Mass. "Evaluating Smartphone Pressure Observations for Mesoscale Analyses and Forecasts." Weather and Forecasting 32, no. 2 (March 3, 2017): 511–31. http://dx.doi.org/10.1175/waf-d-16-0135.1.
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Abstract Smartphone pressure observations have the potential to greatly increase surface observation density on convection-resolving scales. Currently available smartphone pressure observations are tested through assimilation in a mesoscale ensemble for a 3-day, convectively active period in the eastern United States. Both raw pressure (altimeter) observations and 1-h pressure (altimeter) tendency observations are considered. The available observation density closely follows population density, but observations are also available in rural areas. The smartphone observations are found to contain significant noise, which can limit their effectiveness. The assimilated smartphone observations contribute to small improvements in 1-h forecasts of surface pressure and 10-m wind, but produce larger errors in 2-m temperature forecasts. Short-term (0–4 h) precipitation forecasts are improved when smartphone pressure and pressure tendency observations are assimilated as compared with an ensemble that assimilates no observations. However, these improvements are limited to broad, mesoscale features with minimal skill provided at convective scales using the current smartphone observation density. A specific mesoscale convective system (MCS) is examined in detail, and smartphone pressure observations captured the expected dynamic structures associated with this feature. Possibilities for further development of smartphone observations are discussed.
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Curby, Timothy W., Price Johnson, Andrew J. Mashburn, and Lydia Carlis. "Live Versus Video Observations." Journal of Psychoeducational Assessment 34, no. 8 (August 3, 2016): 765–81. http://dx.doi.org/10.1177/0734282915627115.
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When conducting classroom observations, researchers are often confronted with the decision of whether to conduct observations live or by using pre-recorded video. The present study focuses on comparing and contrasting observations of live and video administrations of the Classroom Assessment Scoring System–PreK (CLASS-PreK). Associations between versions, mean differences, reliability, and predictive validity were examined. Results generally indicated high correlations between versions. Video codes were slightly lower on average than live codes. Reliability was generally acceptable in terms of Cronbach’s alpha, but multigroup confirmatory factor models suggested some differences between observation types. Finally, CLASS scores based on each observation type indicated some predictive validity of children’s academic achievement, but no observation type was uniformly better. The discussion focuses on why the codes might differ and the implications of those differences.
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Kwon, Jung Jang. "Implementation of an Automatic Observation System for Cloud Observations." Journal of the Korea Society of Computer and Information 21, no. 2 (February 29, 2016): 79–88. http://dx.doi.org/10.9708/jksci.2016.21.2.079.
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Madaus, Luke E., Gregory J. Hakim, and Clifford F. Mass. "Utility of Dense Pressure Observations for Improving Mesoscale Analyses and Forecasts." Monthly Weather Review 142, no. 7 (June 27, 2014): 2398–413. http://dx.doi.org/10.1175/mwr-d-13-00269.1.
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Abstract The use of dense pressure observations is investigated for creating mesoscale ensemble analyses and improving short-term mesoscale forecasts. By exploiting additional observation platforms, the number of pressure observations over the Pacific Northwest region is increased by an order of magnitude over standard airport observations. Quality control and bias correction methods for these observations are discussed, including the use of pressure tendency as an alternative observation type with fewer bias concerns. The enhanced station density provided by these observations contributes to localized adjustments for a variety of mesoscale phenomena. These adjusted analyses yield improved forecasts, including more accurate forecasts of frontal passages and convective bands. Assimilating dense 3-h pressure tendency observations also reduces the error in some forecast surface fields similarly to raw pressure observations, suggesting further investigation into pressure tendency as a mesoscale observation type.
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Golubaev, А., and A. Mozgova. "The first results of meteor phenomena observations using automated video-spectral meteor patrol of V.N. Karazin Kharkiv National University." Bulletin of Taras Shevchenko National University of Kyiv. Astronomy, no. 59 (2019): 36–41. http://dx.doi.org/10.17721/btsnua.2019.59.36-41.
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In 2018, an observation complex (automatic video-spectral meteor patrol (AVSMP)) was designed and constructed at the Institute of Astronomy, V.N. Karazin Kharkiv National University, for obtaining kinematic and physical characteristics of meteor bodies and their spectra. Cameras were tested in astronomical observations mode with the aim to identify the technical capabilities of the device. This paper presents some of the first results of observations conducted with the help of AVSMP. The created observation complex is intended to expand the material, scientific, as well as educational and scientific base of the Institute of Astronomy. It will be used in the educational process at the Department of Astronomy and Space Informatics of V.N. Karazin KhNU, during practical and laboratory classes, performing bachelor’s and master’s works and developing the newest methods of remote sensing of astronomical objects of the Solar system. In August 2019, the first baseline observations of Perseid’s meteor shower were conducted using AVSMP. At Chuguev observational station of the Institute of Astronomy, where the complex is located, 225 video fragments with meteors in integral light and 98 videos with spectra of meteors were recorded. In Kharkiv, 132 video fragments with meteors in integral light were recorded by the secondary video camera. Of the obtained observation footage, 98 meteors recorded in the integral light are basic, and another 40 video fragments with spectra of meteors have corresponding basic observations in the integral light.
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GUPTA, M. DAS, SOMESHWAR DAS, K. PRASANTHI, P. K. PRADHAN, and U. C. MOHANTY. "Validation of upper-air observations taken during the ARMEX-I and its impact on the global analysis-forecast system." MAUSAM 56, no. 1 (January 19, 2022): 139–46. http://dx.doi.org/10.54302/mausam.v56i1.871.
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During ARMEX-I several special observations were taken over Arabian Sea region and adjoining west coast of India, which gave an opportunity to study this region more thoroughly. To handle such voluminous data, ARMEX data center has been established at National Centre for Medium Range Weather Forecasting (NCMRWF), in collaboration with India Meteorological Department (IMD) and Indian Institute Technology (IIT), Delhi. One of the tasks of this center is to produce reanalysis for ARMEX period, utilizing these observations. It is essential to assimilate every observation from all available sources, especially over the data sparse oceanic regions for accurate determination of the three-dimensional structure of the atmospheric circulation. Before assimilating these data in global data assimilation system of NCMRWF, an attempt has been made to validate some of these data against observational facts from other sources. Upper-air observations (Digicora) from Dabolim, Goa have been compared with RS/RW observation of IMD, at Panjim, Goa. Though the trend in variations of all the meteorological parameters of these two stations is similar but there is a large difference in their absolute values. Reanalysis generated using the specially collected upper-air observations have been compared with the operational analysis of NCMRWF. The impact of these special observations on analysis and forecast system is found to be confined over the Arabian Sea region only in the lower troposphere. However, in the upper troposphere and stratosphere the impact is seen also over the equatorial Indian Ocean region.
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Lupu, Cristina, Pierre Gauthier, and Stéphane Laroche. "Evaluation of the Impact of Observations on Analyses in 3D- and 4D-Var Based on Information Content." Monthly Weather Review 139, no. 3 (March 1, 2011): 726–37. http://dx.doi.org/10.1175/2010mwr3404.1.
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Abstract The degrees of freedom for signal (DFS) is used in data assimilation applications to measure the self-sensitivity of analysis to different observation types. This paper describes a practical method to estimate the DFS of observations from a posteriori statistics. The method does not require the consistency of the error statistics in the analysis system and it is shown that the observational impact on analyses can be estimated from observation departures with respect to analysis or the forecast. This method is first introduced to investigate the impact of a complete set, or subsets, of observations on the analysis for idealized one-dimensional variational data assimilation (1D-Var) analysis experiments and then applied in the framework of the three dimensional (3D)- and four-dimensional (4D)-Var schemes developed at Environment Canada.
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Eisma, Jessica A., Gerrit Schoups, Jeffrey C. Davids, and Nick van de Giesen. "A Bayesian model for quantifying errors in citizen science data: application to rainfall observations from Nepal." Hydrology and Earth System Sciences 27, no. 19 (October 9, 2023): 3565–79. http://dx.doi.org/10.5194/hess-27-3565-2023.
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Abstract. High-quality citizen science data can be instrumental in advancing science toward new discoveries and a deeper understanding of under-observed phenomena. However, the error structure of citizen scientist (CS) data must be well-defined. Within a citizen science program, the errors in submitted observations vary, and their occurrence may depend on CS-specific characteristics. This study develops a graphical Bayesian inference model of error types in CS data. The model assumes that (1) each CS observation is subject to a specific error type, each with its own bias and noise, and (2) an observation's error type depends on the static error community of the CS, which in turn relates to characteristics of the CS submitting the observation. Given a set of CS observations and corresponding ground-truth values, the model can be calibrated for a specific application, yielding (i) number of error types and error communities, (ii) bias and noise for each error type, (iii) error distribution of each error community, and (iv) the single error community to which each CS belongs. The model, applied to Nepal CS rainfall observations, identifies five error types and sorts CSs into four static, model-inferred communities. In the case study, 73 % of CSs submitted data with errors in fewer than 5 % of their observations. The remaining CSs submitted data with unit, meniscus, unknown, and outlier errors. A CS's assigned community, coupled with model-inferred error probabilities, can identify observations that require verification and provides an opportunity for targeted re-training of CSs based on mistake tendencies.