Journal articles: 'Synoptic maps'

1

Rayner, Johnn. "Remarkable Surface Synoptic Maps from the 1930s." Bulletin of the American Meteorological Society 86, no. 11 (November 2005): 1603–8. http://dx.doi.org/10.1175/bams-86-11-1603.

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Hewitson, BC, and RG Crane. "Self-organizing maps: applications to synoptic climatology." Climate Research 22 (2002): 13–26. http://dx.doi.org/10.3354/cr022013.

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Bertello, L., A. A. Pevtsov, G. J. D. Petrie, and D. Keys. "Uncertainties in Solar Synoptic Magnetic Flux Maps." Solar Physics 289, no. 7 (January 14, 2014): 2419–31. http://dx.doi.org/10.1007/s11207-014-0480-3.

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Gibson, Sarah E., David Webb, Ian M. Hewins, Robert H. McFadden, Barbara A. Emery, William Denig, and Patrick S. McIntosh. "Beyond sunspots: Studies using the McIntosh Archive of global solar magnetic field patterns." Proceedings of the International Astronomical Union 12, S328 (October 2016): 93–100. http://dx.doi.org/10.1017/s1743921317003726.

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AbstractIn 1964 (Solar Cycle 20; SC 20), Patrick McIntosh began creating hand-drawn synoptic maps of solar magnetic features, based on Hα images. These synoptic maps were unique in that they traced magnetic polarity inversion lines, and connected widely separated filaments, fibril patterns, and plage corridors to reveal the large-scale organization of the solar magnetic field. Coronal hole boundaries were later added to the maps, which were produced, more or less continuously, into 2009 (i.e., the start of SC 24). The result was a record of ~45 years (~570 Carrington rotations), or nearly four complete solar cycles of synoptic maps. We are currently scanning, digitizing and archiving these maps, with the final, searchable versions publicly available at NOAA's National Centers for Environmental Information. In this paper we present preliminary scientific studies using the archived maps from SC 23. We show the global evolution of closed magnetic structures (e.g., sunspots, plage, and filaments) in relation to open magnetic structures (e.g., coronal holes), and examine how both relate to the shifting patterns of large-scale positive and negative polarity regions.

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Gosain, S., and J. W. Harvey. "Design of a Full Stokes Polarimeter for Chromospheric Measurements with SOLIS/VSM." Proceedings of the International Astronomical Union 10, S305 (December 2014): 186–90. http://dx.doi.org/10.1017/s1743921315004743.

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AbstractThe synoptic observations of the magnetic field of the Sun have continued at the National Solar Observatory (NSO) since 1970s. The daily full-disk maps of the longitudinal magnetic field are regularly combined to form Carrington maps of the photospheric magnetic flux per solar rotation. These maps continue to be used by the international research community for a variety of studies related to solar magnetism as well as for space weather studies. The current NSO synoptic facility is the Synoptic Optical Long-term Investigation of the Sun (SOLIS), which regularly provides photospheric vector and chromospheric longitudinal full-disk magnetograms, among other data products. In the near future, an upgrade of SOLIS to produce chromospheric vector magnetograms is planned. We present the design of a new polarization modulator package for full Stokes polarimetry of the chromospheric Ca II 854.2 nm spectral line.

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Diercke, Andrea, and Carsten Denker. "Synoptic maps in three wavelengths of the Chromospheric Telescope." Proceedings of the International Astronomical Union 14, A30 (August 2018): 339–41. http://dx.doi.org/10.1017/s1743921319004551.

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Abstracthe Chromospheric Telescope (ChroTel) observes the entire solar disk since 2011 in three different chromospheric wavelengths: Hα, Ca ii K, and He i. The instrument records full-disk images of the Sun every three minutes in these different spectral ranges. The ChroTel observations cover the rising and decaying phase of solar cycle 24. We started analyzing the ChroTel time-series and created synoptic maps of the entire observational period in all three wavelength bands. The maps will be used to analyze the poleward migration of quiet-Sun filaments in solar cycle 24.

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Berkovic, Sigalit. "Winter Wind Regimes over Israel Using Self-Organizing Maps." Journal of Applied Meteorology and Climatology 56, no. 10 (October 2017): 2671–91. http://dx.doi.org/10.1175/jamc-d-16-0381.1.

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AbstractThe aim of this study is to objectively define and automatically reconstruct surface wind regimes over Israel. Unlike other previous studies that subjectively examined case studies or applied the semiobjective synoptic classification (SOC), this study shows the ability of the method of self-organizing maps (SOM) to directly define well-known wind regimes at the synoptic hours (0000, 0600, 1200, and 1800 UTC) during the winter. This ability sets the groundwork for future automatic climatological analysis and applications. The investigation is performed by analyzing surface wind measurements from 53 Israel Meteorological Service stations. The relation between the synoptic variables and the wind regimes is revealed from the averages of ECMWF interim reanalysis (ERA-Interim) variables at each SOM wind regime. The inspection of wind regimes and their average pressure anomalies has shown that wind regimes relate to the gradient of the pressure anomalies rather than to the specific isobaric pattern. Two main wind regimes—strong western and strong eastern—are well known over this region. During daytime, SOM classification identifies these two regimes while SOC reveals only strong western regimes since SOC considers depth of the pressure gradients only in the case of low pressure centers. In accordance with previous studies, two main groups—winter low and high pressure centers and/or Red Sea troughs—are related to the strong westerly or easterly wind regimes with low diurnal variability and high daily persistence. Regimes under weak pressure gradients have higher diurnal variability, relatively lower steadiness, and weaker speed. Their daily persistence is not necessarily low.

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Lee, Min-Hee, and Joo-Hong Kim. "The Role of Synoptic Cyclones for the Formation of Arctic Summer Circulation Patterns as Clustered by Self-Organizing Maps." Atmosphere 10, no. 8 (August 19, 2019): 474. http://dx.doi.org/10.3390/atmos10080474.

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Contribution of extra-tropical synoptic cyclones to the formation of mean summer atmospheric circulation patterns in the Arctic domain (≥60° N) was investigated by clustering dominant Arctic circulation patterns based on daily mean sea-level pressure using self-organizing maps (SOMs). Three SOM patterns were identified; one pattern had prevalent low-pressure anomalies in the Arctic Circle (SOM1), while two exhibited opposite dipoles with primary high-pressure anomalies covering the Arctic Ocean (SOM2 and SOM3). The time series of their occurrence frequencies demonstrated the largest inter-annual variation in SOM1, a slight decreasing trend in SOM2, and the abrupt upswing after 2007 in SOM3. Analyses of synoptic cyclone activity using the cyclone track data confirmed the vital contribution of synoptic cyclones to the formation of large-scale patterns. Arctic cyclone activity was enhanced in the SOM1, which was consistent with the meridional temperature gradient increases over the land–Arctic ocean boundaries co-located with major cyclone pathways. The composite daily synoptic evolution of each SOM revealed that all three SOMs persisted for less than five days on average. These evolutionary short-term weather patterns have substantial variability at inter-annual and longer timescales. Therefore, the synoptic-scale activity is central to forming the seasonal-mean climate of the Arctic.

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Lipphardt, B. L., D. Small, A. D. Kirwan, S. Wiggins, K. Ide, C. E. Grosch, and J. D. Paduan. "Synoptic Lagrangian maps: Application to surface transport in Monterey Bay." Journal of Marine Research 64, no. 2 (March 1, 2006): 221–47. http://dx.doi.org/10.1357/002224006777606461.

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Wiley, Jake, and Andrew Mercer. "Synoptic Climatology of Lake-Effect Snow Events off the Western Great Lakes." Climate 9, no. 3 (March 5, 2021): 43. http://dx.doi.org/10.3390/cli9030043.

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As the mesoscale dynamics of lake-effect snow (LES) are becoming better understood, recent and ongoing research is beginning to focus on the large-scale environments conducive to LES. Synoptic-scale composites are constructed for Lake Michigan and Lake Superior LES events by employing an LES case repository for these regions within the U.S. North American Regional Reanalysis (NARR) data for each LES event were used to construct synoptic maps of dominant LES patterns for each lake. These maps were formulated using a previously implemented composite technique that blends principal component analysis with a k-means cluster analysis. A sample case from each resulting cluster was also selected and simulated using the Advanced Weather Research and Forecast model to obtain an example mesoscale depiction of the LES environment. The study revealed four synoptic setups for Lake Michigan and three for Lake Superior whose primary differences were discrepancies in a surface pressure dipole structure previously linked with Great Lakes LES. These subtle synoptic-scale differences suggested that while overall LES impacts were driven more by the mesoscale conditions for these lakes, synoptic-scale conditions still provided important insight into the character of LES forcing mechanisms, primarily the steering flow and air–lake thermodynamics.

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Sheridan, Scott C., and Cameron C. Lee. "Synoptic climatology and the general circulation model." Progress in Physical Geography: Earth and Environment 34, no. 1 (January 22, 2010): 101–9. http://dx.doi.org/10.1177/0309133309357012.

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One of the main research directions of synoptic climatology in recent years has been its application to the output of general circulation models. These applications have spanned the wide array of synoptic techniques, from traditional ones such as correlation-based maps to more recently developed ones such as self-organizing maps and fuzzy clusters. Here, we review the main themes of recent articles, including assessments of the ability of GCMs to replicate historical circulation pattern frequency, as well as the incorporation of synoptic methods to assess GCM capability in producing estimates of precipitation and the likelihood of extreme events. Results from these articles are quite heterogeneous, suggesting that the selection of the GCM, the variables that are used to drive the categorization, and the specific methodology chosen are all important in determining the efficacy of the research and application.

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Bauyrzhanova, Azhar. "The synoptic conditions of air pollution in Temirtau." Bulletin of the Karaganda University. “Biology, medicine, geography Series” 102, no. 2 (June 30, 2021): 89–101. http://dx.doi.org/10.31489/2021bmg2/89-101.

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The article examines the state of air pollution in Temirtau, Karaganda region, and the dynamics of the air pollution index (API). The API is calculated based on the 5 main pollutants in the city, namely suspended particles, nitrogen dioxide, carbon monoxide, phenol and ammonia. The article describes the synoptic conditions of atmospheric air pollution in Temirtau, that is, the influence of baric structures, such as cyclones and anticyclones, troughs and ridges, on the maximum permissible concentration of harmful substances and their time in the city air. The meteorological quantity such as the wind contributing to the transport of pollutants is also considered, and a frequency diagram of the wind direction is presented in order to consider the transboundary transport of harmful substances from other regions. The materials of the article used maps of a certain period of time, such as baric topographic maps and terrestrial synoptic maps, and their analysis was carried out. Based on the results of the analysis of maps of a certain period, the article describes the conditions for the occurrence of synoptic processes favorable for the accumulation of large concentrations of harmful substances in the city. The topic under consideration will be interesting to specialists in the field of natural science, politicians and public figures who pay attention to the ecology of our country, in particular to the ecological system of cities with a large industrial complex, such as Temirtau, and to urgent global environmental problems affecting to the state of atmospheric air quality.

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Chen, Biyan, Wujiao Dai, Zhizhao Liu, Lixin Wu, Cuilin Kuang, and Minsi Ao. "Constructing a precipitable water vapor map from regional GNSS network observations without collocated meteorological data for weather forecasting." Atmospheric Measurement Techniques 11, no. 9 (September 11, 2018): 5153–66. http://dx.doi.org/10.5194/amt-11-5153-2018.

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Abstract. Surface pressure (Ps) and weighted mean temperature (Tm) are two necessary variables for the accurate retrieval of precipitable water vapor (PWV) from Global Navigation Satellite System (GNSS) zenith total delay (ZTD) estimates. The lack of Ps or Tm information is a concern for those GNSS sites that are not collocated with meteorological sensors. This paper investigates an alternative method of inferring accurate Ps and Tm at the GNSS station using nearby synoptic observations. Ps and Tm obtained at the nearby synoptic sites are interpolated onto the location of the GNSS station by performing both vertical and horizontal adjustments, in which the parameters involved in Ps and Tm calculation are estimated from ERA-Interim reanalysis profiles. In addition, we present a method of constructing high-quality PWV maps through vertical reduction and horizontal interpolation of the retrieved GNSS PWVs. To evaluate the performances of the Ps and Tm retrieval, and the PWV map construction, GNSS data collected from 58 stations of the Hunan GNSS network and synoptic observations from 20 nearby sites in 2015 were processed to extract the PWV so as to subsequently generate the PWV maps. The retrieved Ps and Tm and constructed PWV maps were assessed by the results derived from radiosonde and the ERA-Interim reanalysis. The results show that (1) accuracies of Ps and Tm derived by synoptic interpolation are within the range of 1.7–3.0 hPa and 2.5–3.0 K, respectively, which are much better than the GPT2w model; (2) the constructed PWV maps have good agreements with radiosonde and ERA-Interim reanalysis data with the overall accuracy being better than 3 mm; and (3) PWV maps can well reveal the moisture advection, transportation and convergence during heavy rainfall.

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14

Gazis, P. R. "Synoptic maps of solar wind parameters from in situ spacecraft observations." Journal of Geophysical Research: Space Physics 100, A3 (March 1, 1995): 3383–93. http://dx.doi.org/10.1029/94ja02629.

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Tymvios, F., K. Savvidou, and S. C. Michaelides. "Association of geopotential height patterns with heavy rainfall events in Cyprus." Advances in Geosciences 23 (June 23, 2010): 73–78. http://dx.doi.org/10.5194/adgeo-23-73-2010.

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Abstract. Dynamically induced rainfall is strongly connected with synoptic atmospheric circulation patterns at the upper levels. This study investigates the relationship between days of high precipitation volume events in the eastern Mediterranean and the associated geopotential height patterns at 500 hPa. To reduce the number of different patterns and to simplify the statistical processing, the input days were classified into clusters of synoptic cases having similar characteristics, by utilizing Kohonen Self Organizing Maps (SOM) architecture. Using this architecture, synoptic patterns were grouped into 9, 18, 27 and 36 clusters which were subsequently used in the analysis. The classification performance was tested by applying the method to extreme rainfall events in the eastern Mediterranean. The relationship of the synoptic upper air patterns (500 hPa height) and surface features (heavy rainfall events) was established, while the 36 member classification proved to be the most efficient.

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Schauer, Andrew R., Jordy Hendrikx, Karl W. Birkeland, and Cary J. Mock. "Synoptic atmospheric circulation patterns associated with deep persistent slab avalanches in the western United States." Natural Hazards and Earth System Sciences 21, no. 2 (February 25, 2021): 757–74. http://dx.doi.org/10.5194/nhess-21-757-2021.

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Abstract. Deep persistent slab avalanches are capable of destroying infrastructure and are usually unsurvivable for those who are caught. Formation of a snowpack conducive to deep persistent slab avalanches is typically driven by meteorological conditions occurring in the beginning weeks to months of the winter season, and yet the avalanche event may not occur for several weeks to months later. While predicting the exact timing of the release of deep persistent slab avalanches is difficult, onset of avalanche activity is commonly preceded by rapid warming, heavy precipitation, or high winds. This work investigates the synoptic drivers of deep persistent slab avalanches at three sites in the western USA with long records: Bridger Bowl, Montana; Jackson, Wyoming; and Mammoth Mountain, California. We use self-organizing maps to generate 20 synoptic types that summarize 5899 daily 500 mbar geopotential height maps for the winters (November–March) of 1979/80–2017/18. For each of the three locations, we identify major and minor deep persistent slab avalanche seasons and analyze the number of days represented by each synoptic type during the beginning (November–January) of the major and minor seasons. We also examine the number of days assigned to each synoptic type during the 72 h preceding deep persistent slab avalanche activity for both dry and wet slab events. Each of the three sites exhibits a unique distribution of the number of days assigned to each synoptic type during November–January of major and minor seasons and for the 72 h period preceding deep persistent slab avalanche activity. This work identifies the synoptic-scale atmospheric circulation patterns contributing to deep persistent slab instabilities and the patterns that commonly precede deep persistent slab avalanche activity. By identifying these patterns, we provide an improved understanding of deep persistent slab avalanches and an additional tool to anticipate the timing of these difficult-to-predict events.

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Koshlyakov, M. N., I. A. Repina, D. S. Savchenko, R. Yu Tarakanov, and V. K. Taroyan. "Structure and variability of the synoptic disturbances of ocean currents in the Drake Passage and Scotia Sea." Океанология 59, no. 2 (June 9, 2019): 191–200. http://dx.doi.org/10.31857/s0030-1574592191-200.

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Twenty two years data of the satellite altimeter observations are used for the analysis of structure and variability of the ocean current synoptic disturbances in the Drake Passage and Scotia Sea. Wavelet analysis of the time series of ocean surface absolute dynamics topography (OSADT) at a set of points in the studied ocean area has revealed a high degree of the statistical nonstationarity of these series appearing as short (few years) intervals of intensive fluctuations of OSADT separated by long intervals of weak fluctuations. Analysis of the synoptic OSADT maps has showed that the intervals of the strong ocean current fluctuations at a point are conditioned by the alternation of processes of cyclonic and anticyclonic eddy-meanders formation by the jets of Antarctic Circumpolar Current, strengthening of the eddies, their following attenuation and final eddy confluence with the mother jets. Besides of the statistical nonstationarity, a considerable spatial variability of the statistical characteristics of the ocean current synoptical disturbances has been revealed for the scales of 150–200 km.

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Verdon-Kidd, D., and A. S. Kiem. "On the relationship between large-scale climate modes and regional synoptic patterns that drive Victorian rainfall." Hydrology and Earth System Sciences Discussions 5, no. 5 (October 10, 2008): 2791–815. http://dx.doi.org/10.5194/hessd-5-2791-2008.

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Abstract. In this paper regional (synoptic) and large-scale climate drivers of rainfall are investigated for Victoria, Australia. A non-linear classification methodology known as self-organizing maps (SOM) is used to identify 20 key regional synoptic patterns, which are shown to capture a range of significant synoptic features known to influence the climate of the region. Rainfall distributions are assigned to each of the 20 patterns for nine rainfall stations located across Victoria, resulting in a clear distinction between wet and dry synoptic types at each station. The influence of large-scale climate modes on the frequency and timing of the regional synoptic patterns is also investigated. This analysis revealed that phase changes in the El Niño Southern Oscillation (ENSO), the Southern Annular Mode (SAM) and/or Indian Ocean Dipole (IOD) are associated with a shift in the relative frequency of wet and dry synoptic types. Importantly, these results highlight the potential to utilise the link between the regional synoptic patterns derived in this study and large-scale climate modes to improve rainfall forecasting for Victoria, both in the short- (i.e. seasonal) and long-term (i.e. decadal/multi-decadal scale). In addition, the regional and large-scale climate drivers identified in this study provide a benchmark by which the performance of Global Climate Models (GCMs) may be assessed.

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Solecki, Mateusz. "Warunki powstania zjawiska downburst nad Wrocławiem w dniu 30 VI 2016." Prace i Studia Geograficzne 66, no. 1 (March 29, 2021): 35–45. http://dx.doi.org/10.48128/pisg/2021-66.1-03.

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The article presents the issue of downburst over Poland. Strong downdrafts are a great danger in aviation, but can also cause damage on the surface of the Earth. On the basis of synoptic maps, aerological and radar data the analysis of synoptic and thermodynamic conditions of the atmosphere in which the phenomenon occurred was conducted. The appearance of the cold front over Lower Silesia and the occurrence of V-notch radar signature over Wroclaw may have suggested the formation of a storm and the associated downburst.

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Berkovic, Sigalit. "Wind regimes and their relation to synoptic variables using self-organizing maps." Advances in Science and Research 15 (January 25, 2018): 1–9. http://dx.doi.org/10.5194/asr-15-1-2018.

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Abstract. This study exemplifies the ability of the self-organizing maps (SOM) method to directly define well known wind regimes over Israel during the entire year, except summer period, at 12:00 UTC. This procedure may be applied at other hours and is highly relevant to future automatic climatological analysis and applications. The investigation is performed by analysing surface wind measurements from 53 Israel Meteorological Service stations. The relation between the synoptic variables and the wind regimes is revealed from the averages of ECMWF ERA-INTERIM reanalysis variables for each SOM wind regime. The inspection of wind regimes and their average geopotential anomalies has shown that wind regimes relate to the gradient of the pressure anomalies, rather than to the specific isobars pattern. Two main wind regimes – strong western and the strong eastern or northern – are well known over this region. The frequencies of the regimes according to seasons is verified. Strong eastern regimes are dominant during winter, while strong western regimes are frequent in all seasons.

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Hick, P., B. Jackson, and R. Schwenn. "Synoptic maps constructed from brightness observations of Thomson scattering by heliospheric electrons." Advances in Space Research 11, no. 1 (January 1991): 61–64. http://dx.doi.org/10.1016/0273-1177(91)90091-w.

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22

MOHAPATRA, M., H. R. BISWAS, and G. K. SAWAISARJE. "Daily summer monsoon rainfall over northeast India due to synoptic scale systems." MAUSAM 59, no. 1 (November 27, 2021): 35–50. http://dx.doi.org/10.54302/mausam.v59i1.1130.

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The summer monsoon rainfall over northeast India mostly depends on the synoptic systems over the region and neighbourhood and the convection due to the interaction of orography with the synoptic and sub-synoptic scale systems. Hence, an attempt is made to analyse the mean daily rainfall distribution over northeast India due to different synoptic systems like Low Pressure Systems (LPS) and cyclonic circulations (cycir) extending upto lower/middle tropospheric levels over different regions. The mean daily rainfall due to monsoon trough over various locations in northeast India is also analysed. For the above purpose, the rainfall data over 50 uniformly distributed stations in northeast India during summer monsoon season (June-September) for a period of 10 years (1991-2000) are considered. The principal objective of the study is to find out the contribution of the different synoptic systems to the spatial variability of monsoon rainfall over northeast India. The developed synoptic analog maps may be useful to the forecasters for 24 hours rainfall forecast with the knowledge of location, intensity and movement of the synoptic systems. Based on larger data set, the results confirm the earlier findings (Srinivasan et al., 1972) with respect to rainfall due to monsoon trough and LPS. The Low Level Cycir (LLC) also plays significant role on the rainfall variability over northeast India, as the number of LLC days is significantly higher over the region, contrary to the days of occurrence of LPS. The study finds out the regions of excess/deficient rainfall and active/weak monsoon conditions due to different synoptic systems.

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Verdon-Kidd, D. C., and A. S. Kiem. "On the relationship between large-scale climate modes and regional synoptic patterns that drive Victorian rainfall." Hydrology and Earth System Sciences 13, no. 4 (April 7, 2009): 467–79. http://dx.doi.org/10.5194/hess-13-467-2009.

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Abstract. In this paper regional (synoptic) and large-scale climate drivers of rainfall are investigated for Victoria, Australia. A non-linear classification methodology known as self-organizing maps (SOM) is used to identify 20 key regional synoptic patterns, which are shown to capture a range of significant synoptic features known to influence the climate of the region. Rainfall distributions are assigned to each of the 20 patterns for nine rainfall stations located across Victoria, resulting in a clear distinction between wet and dry synoptic types at each station. The influence of large-scale climate modes on the frequency and timing of the regional synoptic patterns is also investigated. This analysis revealed that phase changes in the El Niño Southern Oscillation (ENSO), the Indian Ocean Dipole (IOD) and/or the Southern Annular Mode (SAM) are associated with a shift in the relative frequency of wet and dry synoptic types on an annual to inter-annual timescale. In addition, the relative frequency of synoptic types is shown to vary on a multi-decadal timescale, associated with changes in the Inter-decadal Pacific Oscillation (IPO). Importantly, these results highlight the potential to utilise the link between the regional synoptic patterns derived in this study and large-scale climate modes to improve rainfall forecasting for Victoria, both in the short- (i.e. seasonal) and long-term (i.e. decadal/multi-decadal scale). In addition, the regional and large-scale climate drivers identified in this study provide a benchmark by which the performance of Global Climate Models (GCMs) may be assessed.

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Guardans, R., and I. Palomino. "Description of Wind Field Dynamic Patterns in a Valley and Their Relation to Mesoscale and Synoptic-Scale Meteorological Situations." Journal of Applied Meteorology 34, no. 1 (January 1, 1995): 49–67. http://dx.doi.org/10.1175/1520-0450-34.1.49.

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Abstract A large set of hourly meteorological data from seven towers deployed in Montesina Valley (Cordoba, Spain) is studied in relation to the prevailing synoptic situation. The complete collection of daily synoptic maps for 1985-90 has been classified in seven basic weather patterns. First-order transition probabilities and weatherpattern persistences have been calculated for each of the patterns. The behavior of the local valley wind field is described as a function of the synoptic patterns. The work reported here, based on observations of the characteristic time and space patterns of flow in the valley under different synoptic conditions, has made it possible to obtain a set of empirical rules and regression functions to produce forecasts of the local wind field as a function of the synoptic situation and the hour of the day to be used in the emergency plans. The result of this work is currently being implemented in an atmospheric dispersion module of an expert system that will be used as a tool to predict the evolution of accidental and routine hazardous emissions to the atmosphere in complex terrain such as valleys and coastal areas.

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Benevolenskaya, E. E., A. G. Kosovichev, and P. H. Scherrer. "Active Longitudinal Structures of the Sun from MDI and EIT Observations." Symposium - International Astronomical Union 203 (2001): 251–53. http://dx.doi.org/10.1017/s0074180900219219.

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We present results of investigation of the large-scale structure of the solar corona during the transition period between solar cycles 22 and 23 and at the beginning of the current cycle 23 using the SOHO/EIT EUV data obtained in 171 Å, 195 Å, 284 Å and 304 Å lines. For this analysis the data were transformed into synoptic maps for each of the spectral lines, and for the 195/171 line ratio which is an index of the coronal temperature. The synoptic maps reveal stable longitudinal structures in the coronal intensities and temperature, which are related to large-scale magnetic field structures. We discuss the relation between the coronal and photospheric magnetic structures obtained from the SOHO/MDI data, and compare the rotation rates of these structures with the rotation profile of the solar interior in order to determine the possible origin of the coronal structures.

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Sheridan, Scott C., and Cameron C. Lee. "The self-organizing map in synoptic climatological research." Progress in Physical Geography: Earth and Environment 35, no. 1 (February 2011): 109–19. http://dx.doi.org/10.1177/0309133310397582.

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Self-organizing maps (SOMs) are a relative newcomer to synoptic climatology; the method itself has only been utilized in the field for around a decade. In this article, we review the major developments and climatological applications of SOMs in the literature. The SOM can be used in synoptic climatological analysis in a manner similar to most other clustering methods. However, as the results from a SOM are generally represented by a two-dimensional array of cluster types that ‘self-organize’, the synoptic categories in the array effectively represent a continuum of synoptic categorizations, compared with discrete realizations produced through most traditional methods. Thus, a larger number of patterns can be more readily understood, and patterns, as well as transitional nodes between patterns, can be discerned. Perhaps the most intriguing development with SOMs has been the new avenues of visualization; the resultant spatial patterns of any variable can be more readily understood when displayed in a SOM. This improved visualization has led to SOMs becoming an increasingly popular tool in various research with climatological applications from other disciplines as well.

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Udy, Danielle G., Tessa R. Vance, Anthony S. Kiem, Neil J. Holbrook, and Mark A. J. Curran. "Links between Large-Scale Modes of Climate Variability and Synoptic Weather Patterns in the Southern Indian Ocean." Journal of Climate 34, no. 3 (February 2021): 883–99. http://dx.doi.org/10.1175/jcli-d-20-0297.1.

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AbstractWeather systems in the southern Indian Ocean (SIO) drive synoptic-scale precipitation variability in East Antarctica and southern Australia. Improved understanding of these dynamical linkages is beneficial to diagnose long-term climate changes from climate proxy records as well as informing regional weather and climate forecasts. Self-organizing maps (SOMs) are used to group daily 500-hPa geopotential height (z500; ERA-Interim) anomalies into nine regional synoptic types based on their dominant patterns over the SIO (30°–75°S, 40°–180°E) from January 1979 to October 2018. The pattern anomalies represented include four meridional, three mixed meridional–zonal, one zonal, and one transitional node. The frequency of the meridional nodes shows limited association with the phase of the southern annular mode (SAM), especially during September–November. The zonal and mixed patterns were nevertheless strongly and significantly correlated with SAM, although the regional synoptic representation of SAM+ conditions was not zonally symmetric and was represented by three separate nodes. We recommend consideration of how different synoptic conditions vary the atmospheric representation of SAM+ in any given season in the SIO. These different types of SAM+ mean a hemispheric index fails to capture the regional variability in surface weather conditions that is primarily driven by the synoptic variability rather than the absolute polarity of the SAM.

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Nikolić, L. "On Solutions of the PFSS Model With GONG Synoptic Maps for 2006–2018." Space Weather 17, no. 8 (August 2019): 1293–311. http://dx.doi.org/10.1029/2019sw002205.

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Virtanen, I. O. I., I. I. Virtanen, A. A. Pevtsov, L. Bertello, A. Yeates, and K. Mursula. "Reconstructing solar magnetic fields from historical observations." Astronomy & Astrophysics 627 (June 25, 2019): A11. http://dx.doi.org/10.1051/0004-6361/201935606.

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Aims. The evolution of the photospheric magnetic field has only been regularly observed since the 1970s. The absence of earlier observations severely limits our ability to understand the long-term evolution of solar magnetic fields, especially the polar fields that are important drivers of space weather. Here, we test the possibility to reconstruct the large-scale solar magnetic fields from Ca II K line observations and sunspot magnetic field observations, and to create synoptic maps of the photospheric magnetic field for times before modern-time magnetographic observations. Methods. We reconstructed active regions from Ca II K line synoptic maps and assigned them magnetic polarities using sunspot magnetic field observations. We used the reconstructed active regions as input in a surface flux transport simulation to produce synoptic maps of the photospheric magnetic field. We compared the simulated field with the observed field in 1975−1985 in order to test and validate our method. Results. The reconstruction very accurately reproduces the long-term evolution of the large-scale field, including the poleward flux surges and the strength of polar fields. The reconstruction has slightly less emerging flux because a few weak active regions are missing, but it includes the large active regions that are the most important for the large-scale evolution of the field. Although our reconstruction method is very robust, individual reconstructed active regions may be slightly inaccurate in terms of area, total flux, or polarity, which leads to some uncertainty in the simulation. However, due to the randomness of these inaccuracies and the lack of long-term memory in the simulation, these problems do not significantly affect the long-term evolution of the large-scale field.

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Jolly, Ben, Adrian J. McDonald, Jack H. J. Coggins, Peyman Zawar-Reza, John Cassano, Matthew Lazzara, Geoffery Graham, Graeme Plank, Orlon Petterson, and Ethan Dale. "A Validation of the Antarctic Mesoscale Prediction System Using Self-Organizing Maps and High-Density Observations from SNOWWEB." Monthly Weather Review 144, no. 9 (September 2016): 3181–200. http://dx.doi.org/10.1175/mwr-d-15-0447.1.

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This study compares high-resolution output (1.1-km horizontal grid length) from twice-daily forecasts produced by the Antarctic Mesoscale Prediction System (AMPS) with a dense observational network east of Ross Island. Covering 10 000 km2, 15 SNOWWEB stations significantly increased the number of observation stations in the area to 19 during the 2014–15 austral summer. Collocated “virtual stations” created from AMPS output are combined with observations, producing a single dataset of zonal and meridional wind components used to train a self-organizing map (SOM). The resulting SOM is used to individually classify the observational and AMPS datasets, producing a time series of classifications for each dataset directly comparable to the other. Analysis of class composites shows two dominant weather patterns: low but directionally variable winds and high but directionally constant winds linked to the Ross Ice Shelf airstream (RAS). During RAS events the AMPS and SNOWWEB data displayed good temporal class alignment with good surface wind correlation. SOM analysis shows that AMPS did not accurately forecast surface-level wind speed or direction during light wind conditions where synoptic forcing was weak; however, it was able to forecast the low wind period occurrence accurately. Coggins’s regimes provide synoptic-scale context and show a reduced synoptic pressure gradient during these classes, increasing reliance on the ability of Polar WRF to resolve mesoscale dynamics. Available initialization data have insufficient resolution for the region’s complex topography, which likely impacts performance. The SOM analysis methods used are shown to be effective for model validation and are widely applicable.

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Makarov, V. I., and K. R. Sivaraman. "Global Evolution of Photospheric Magnetic Fields." Symposium - International Astronomical Union 138 (1990): 281–95. http://dx.doi.org/10.1017/s0074180900044247.

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The main features concerning the evolution of the large scale photospheric magnetic fields derived from synoptic maps as well as from H-alpha synoptic charts are reviewed. The significance of a variety of observations that indicate the presence of a high latitude component as a counterpart to the sunspot phenomenon at lower latitudes is reviewed. It is argued that these two components describe the global magnetic field on the sun. It is demonstrated that this scenario is able to link many phenomena observed on the sun (coronal emission, ephemeral active regions, geomagnetic activity, torsional oscillations, polar faculae and global modes in the magnetic field pattern) with the global magnetic activity.

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Michaelides, S., F. Tymvios, and D. Charalambous. "Investigation of trends in synoptic patterns over Europe with artificial neural networks." Advances in Geosciences 23 (November 15, 2010): 107–12. http://dx.doi.org/10.5194/adgeo-23-107-2010.

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Abstract. The present study is a comprehensive application of a methodology developed for the classification of synoptic situations using artificial neural networks. In this respect, the 500 hPa geopotential height patterns at 12:00 UTC (Universal Time Coordinated) determined from the reanalysis data (ERA-40 dataset) of the European Centre for Medium range Weather Forecasts (ECMWF) over Europe were used. The dataset covers a period of 45 years (1957–2002) and the neural network methodology applied is the SOM architecture (Self Organizing Maps). The classification of the synoptic scale systems was conducted by considering 9, 18, 27 and 36 synoptic patterns. The statistical analysis of the frequency distribution of the classification results for the 36 clusters over the entire 44-year period revealed significant tendencies in the frequency distribution of certain clusters, thus substantiating a possible climatic change. In the following, the database was split into two periods, the "reference" period that includes the first 30 years and the "test" period comprising the remaining 14 years.

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De Santis, Vincenzo, Massimo Caldara, Antonella Marsico, Domenico Capolongo, and Luigi Pennetta. "Evolution of the Ofanto River delta from the ‘Little Ice Age’ to modern times: Implications of large-scale synoptic patterns." Holocene 28, no. 12 (September 10, 2018): 1948–67. http://dx.doi.org/10.1177/0959683618798109.

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We reconstruct the evolution of the Ofanto River delta from the 17th century to the present using historical maps (1600–1850), official IGM topographic maps (1850–1980) and recent aerial photographs (2015), and we compare long-term morphological changes with the evolution of the delta of the Volturno River during the same time period. The aim of this study is to define the role of climatic (flood frequency, synoptic pressure patterns) and anthropogenic factors (deforestation, anthropogenic sediment subtraction of river sediment) in the evolution of the Ofanto delta. We analysed the importance of each factor on the evolution of the delta and compared them with the simultaneous behaviour of the Volturno delta to highlight the role of large-scale synoptic pressure patterns. We found that the main driver of different delta evolution phases is weather-climatic condition, while anthropogenic factors interacted with the delta evolution in different ways but did not control the first-order evolution. In particular, analysing the data on recent floods, we found that the most favourable situations for both rivers are omega-blocking, deep low-pressure trough and strong meridional circulation (mode Ω) which create Mediterranean low-pressure systems. Instead, a zonal circulation (mode W) can only cause floods on Volturno. Because the evolution of a delta is driven by the frequency of floods, and because we found that the frequency of floods is guided by synoptic patterns, a relationship can be established between delta evolution and synoptic patterns in the past. Consequently, past phases of the contemporary progradation of the Ofanto and Volturno deltas suggest the increasing frequency of mode Ω, while phases of simultaneous progradation of the Volturno delta and stability and/or retreat of the Ofanto delta are indicative of the increasing frequency of mode W. The only exception occurred during the last evolutionary phase (60 years), when anthropogenic sediment subtraction was prevalent.

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Vecchio, A., M. Laurenza, D. Meduri, V. Carbone, and M. Storini. "Spatio-temporal variability of the photospheric magnetic field." Proceedings of the International Astronomical Union 6, S274 (September 2010): 204–6. http://dx.doi.org/10.1017/s1743921311006946.

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AbstractThe spatio-temporal dynamics of the solar magnetic field has been investigated by using NSO/Kitt Peak synoptic magnetic maps covering ~28 yr. For each heliographic latitude the field has been analyzed through the Empirical Mode Decomposition, in order to investigate the time evolution of the various characteristic oscillating frequencies. Preliminary results are discussed.

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Mechem, David B., Carly S. Wittman, Matthew A. Miller, Sandra E. Yuter, and Simon P. de Szoeke. "Joint Synoptic and Cloud Variability over the Northeast Atlantic near the Azores." Journal of Applied Meteorology and Climatology 57, no. 6 (June 2018): 1273–90. http://dx.doi.org/10.1175/jamc-d-17-0211.1.

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AbstractMarine boundary layer clouds are modified by processes at different spatial and temporal scales. To isolate the processes governing aerosol–cloud–precipitation interactions, multiday synoptic variability of the environment must be accounted for. Information on the location of low clouds relative to the ridge–trough pattern gives insight into how cloud properties vary as a function of environmental subsidence and stability. The technique of self-organizing maps (SOMs) is employed to objectively classify the 500-hPa geopotential height patterns for 33 years of reanalysis fields (ERA-Interim) into pretrough, trough, posttrough, ridge, and zonal-flow categories. The SOM technique is applied to a region of prevalent marine low cloudiness over the eastern North Atlantic Ocean that is centered on the Azores island chain, the location of a long-term U.S. Department of Energy observation site. The Azores consistently lie in an area of substantial variability in synoptic configuration, thermodynamic environment, and cloud properties. The SOM method was run in two ways to emphasize multiday and seasonal variability separately. Over and near the Azores, there is an east-to-west sloshing back and forth of the western edge of marine low clouds associated with different synoptic states. The different synoptic states also exhibit substantial north–south variability in the position of high clouds. For any given month of the year, there is large year-to-year variability in the occurrence of different synoptic states. Hence, estimating the climatological behavior of clouds from short-term field campaigns has large uncertainties. This SOM approach is a robust method that is broadly applicable to characterizing synoptic regimes for any location.

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Prezerakos, N. G., A. G. Paliatsos, and K. V. Koukouletsos. "Diagnosis of the Relationship between Dust Storms over the Sahara Desert and Dust Deposit or Coloured Rain in the South Balkans." Advances in Meteorology 2010 (2010): 1–14. http://dx.doi.org/10.1155/2010/760546.

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The main objects of study in this paper are the synoptic scale atmospheric circulation systems associated with the rather frequent phenomenon of coloured rain and the very rare phenomenon of dust or sand deposits from a Saharan sandstorm triggered by a developing strong depression. Analysis of two such cases revealed that two days before the occurrence of the coloured rain or the dust deposits over Greece a sand storm appeared over the north-western Sahara desert. The flow in the entire troposphere is southerly/south-westerly with an upward vertical motion regime. If the atmospheric conditions over Greece favour rain then this rain contains a part of the dust cloud while the rest is drawn away downstream adopting a light yellow colour. In cases where the atmospheric circulation on the route of the dust cloud trajectories is not intensively anticyclonic dust deposits can occur on the surface long far from the region of the dust origin. Such was the case on 4th April, 1988, when significant synoptic-scale subsidence occurred over Italy and towards Greece. The upper air data, in the form of synoptic maps, illustrate in detail the synoptic-scale atmospheric circulations associated with the emission-transport-deposition and confirm the transportation of dust particles.

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Podnebesnykh, N. V. "Large-Scale Atmospheric Circulation over Siberia by Data from Surface Synoptic Maps and Reanalysis." Izvestiya Rossiiskoi Akademii Nauk. Seriya Geograficheskaya., no. 3 (July 26, 2015): 94. http://dx.doi.org/10.15356/0373-2444-2015-3-94-99.

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Gibson, Peter B., Sarah E. Perkins-Kirkpatrick, and James A. Renwick. "Projected changes in synoptic weather patterns over New Zealand examined through self-organizing maps." International Journal of Climatology 36, no. 12 (January 25, 2016): 3934–48. http://dx.doi.org/10.1002/joc.4604.

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Lennard, Christopher, and Gabriele Hegerl. "Relating changes in synoptic circulation to the surface rainfall response using self-organising maps." Climate Dynamics 44, no. 3-4 (May 13, 2014): 861–79. http://dx.doi.org/10.1007/s00382-014-2169-6.

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Pevtsov, Alexei A., Luca Bertello, and Peter MacNeice. "Effect of uncertainties in solar synoptic magnetic flux maps in modeling of solar wind." Advances in Space Research 56, no. 12 (December 2015): 2719–26. http://dx.doi.org/10.1016/j.asr.2015.05.043.

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Schädler, Gerd, and Rüdiger Sasse. "Analysis of the connection between precipitation and synoptic scale processes in the Eastern Mediterranean using self-organizing maps." Meteorologische Zeitschrift 15, no. 3 (July 10, 2006): 273–78. http://dx.doi.org/10.1127/0941-2948/2006/0105.

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Luo, Yali, Mengwen Wu, Fumin Ren, Jian Li, and Wai-Kin Wong. "Synoptic Situations of Extreme Hourly Precipitation over China." Journal of Climate 29, no. 24 (November 21, 2016): 8703–19. http://dx.doi.org/10.1175/jcli-d-16-0057.1.

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Abstract In this study, synoptic situations associated with extreme hourly precipitation over China are investigated using rain gauge data, weather maps, and composite radar reflectivity data. Seasonal variations of hourly precipitation (>0.1 mm h−1) suggest complicated regional features in the occurrence frequency and intensity of rainfall. The 99.9th percentile is thus used as the threshold to define the extreme hourly rainfall for each station. The extreme rainfall is the most intense over the south coastal areas and the North China Plain. About 77% of the extreme rainfall records occur in summer with a peak in July (30.4%) during 1981–2013. Nearly 5800 extreme hourly rainfall records in 2011–15 are classified into four types according to the synoptic situations under which they occur: the tropical cyclone (TC), surface front, vortex/shear line, and weak-synoptic forcing. They contribute 8.0%, 13.9%, 39.1%, and 39.0%, respectively, to the total occurrence and present distinctive characteristics in regional distribution and seasonal or diurnal variations. The TC type occurs most frequently along the coasts and decreases progressively toward inland China; the frontal type is distributed relatively evenly east of 104°E; the vortex/shear line type shows a prominent center over the Sichuan basin with two high-frequency bands extending from the center southeastward and northeastward, respectively; and the weak-synoptic type occurs more frequently in southeast, southwest, and northern China, and in the easternmost area of northeast China. Occurrences of the weak-synoptic type have comparable contributions from mesoscale convective systems and smaller-scale storms with notable differences in their preferred locations.

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Leirias, Renata Barros Vasconcelos, Natalia Fedorova, and Vladimir Levit. "Airplane Emergency Landing Due to Quick Development of Mesoscale Convective Complexes." Meteorology 2, no. 1 (January 3, 2023): 1–14. http://dx.doi.org/10.3390/meteorology2010001.

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Some meteorological phenomena in South America develop quickly and take on large dimensions. These phenomena cause disasters for aviation, such as incidents and accidents. Mesoscale convective complexes (MCCs) forced a commercial airplane into an emergency landing at Ezeiza International Airport in Buenos Aires (Argentina) in October 2018. The airplane took off from São Paulo (Brazil) to Santiago (Chile) and had to alternate to Ezeiza after encountering unanticipated agglomerations of MCCs along the flight route; its structure was seriously damaged, which affected the safety of the flight. A synoptic and thermodynamic analysis of the atmosphere, prior to the event, was made based on GOES16 infrared satellite data, radiosonde data, maps of several variables such as stream lines, temperature advection, surface synoptic maps and layer thickness from CPTEC/INPE and NCEP reanalysis data. The main observed processes that influenced the formation and development of conglomerates of MCCs were the following: (1) the cyclogenesis of a baroclinic cyclone on the cold front; (2) the coupling of subtropical and polar jet streams; (3) the advection of warm and humid air along a low-level jet stream. Recommendations for meteorologists in weather forecasting and for aviators in flight safety were prepared.

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Nigro, Melissa A., and John J. Cassano. "Identification of Surface Wind Patterns over the Ross Ice Shelf, Antarctica, Using Self-Organizing Maps." Monthly Weather Review 142, no. 7 (June 27, 2014): 2361–78. http://dx.doi.org/10.1175/mwr-d-13-00382.1.

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Abstract The interaction of synoptic and mesoscale circulations with the steep topography surrounding the Ross Ice Shelf, Antarctica, greatly influences the wind patterns in the region of the Ross Ice Shelf. The topography provides forcing for features such as katabatic winds, barrier winds, and barrier wind corner jets. The combination of topographic forcing and synoptic and mesoscale forcing from cyclones that traverse the Ross Ice Shelf sector create a region of strong but varying winds. This paper identifies the dominant surface wind patterns over the Ross Ice Shelf using output from the Weather Research and Forecasting Model run within the Antarctic Mesoscale Prediction System and the method of self-organizing maps (SOM). The dataset has 15-km grid spacing and is the first study to identify the dominant surface wind patterns using data at this resolution. The analysis shows that the Ross Ice Shelf airstream, a dominant stream of air flowing northward from the interior of the continent over the western and/or central Ross Ice Shelf to the Ross Sea, is present over the Ross Ice Shelf approximately 34% of the time, the Ross Ice Shelf airstream varies in both its strength and position over the Ross Ice Shelf, and barrier wind corner jets are present in the region to the northwest of the Prince Olav Mountains approximately 14% of the time and approximately 41% of the time when the Ross Ice Shelf airstream is present.

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Bommier, Véronique. "24 synoptic maps 1974-1982 (ascending phase of cycle XXI) of 323 prominence average magnetic fields measured by the Hanle effect." Proceedings of the International Astronomical Union 8, S300 (June 2013): 397–400. http://dx.doi.org/10.1017/s1743921313011265.

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AbstractThe poster was made of 323 average prominence magnetic fields reported on 24 synoptic maps. The paper first resumes the methods for the field derivation, and the different results of the whole program of these second generation Hanle effect observations. From their conclusions, it was possible to derive a unique field vector for each of the 323 prominences. The maps put in evidence a large scale structure of the prominence magnetic field, probably distorted by the differential rotation, which leads to a systematically small angle (on the order of 30°) between the field vector and the prominence long axis.

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Mutar, Aqeel Ghazi, Asraa Khtan, and Loay E. George. "Synoptic Characteristics of Torrential Rains in Southwest and Southeast Iraq: A Case Study." Al-Mustansiriyah Journal of Science 32, no. 3 (June 24, 2021): 1. http://dx.doi.org/10.23851/mjs.v32i3.957.

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Torrential rains cause many losses in city infrastructure, crops, and deaths in several regions of the world including Iraq as in the case that we will discuss in this work, on January 28 and 29, 2019. Torrential rain caused the flow of torrents in several areas of Iraq and the neighboring areas. This research work aims to identify the synoptic characteristics of torrential rains and the causes of this case. This will be done by analyzing and interpreting the weather maps at different pressure levels with focusing on the troughs and fronts locations, relative vorticity, polar jet stream effect as well as the moisture flux. The Geographic Information System (GIS) was used to analyze the satellite images in order to calculate the Normalized Difference Water Index (NDWI) to confirm the heavy rain case. The weather maps were obtained from the Modern-Era Retrospective analysis for Research and Applications Version 2 (MERRA-2). As for the satellite images we used the satellite imagery from Sentinel-2 and EMUTSAT.

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Illarionov, Egor, Alexander Kosovichev, and Andrey Tlatov. "Machine-learning Approach to Identification of Coronal Holes in Solar Disk Images and Synoptic Maps." Astrophysical Journal 903, no. 2 (November 9, 2020): 115. http://dx.doi.org/10.3847/1538-4357/abb94d.

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Davies, Jonathan M. "Meteorological Setting for a Catastrophic Event: The Deadly Joplin Tornado of 22 May 2011." E-Journal of Severe Storms Meteorology 12, no. 3 (October 5, 2021): 1–23. http://dx.doi.org/10.55599/ejssm.v12i3.68.

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The tornado that struck Joplin, MO on 22 May 2011 resulted in the first triple-digit death toll from a single tornado in the United States since the 1950s. This paper documents the meteorological setting for this exceptional event, as no published studies have done so yet. Synoptic-scale surface and upper air maps, a brief radar overview, environmental parameters via the SPC mesoanalysis and soundings, and mesoscale surface analysis are used to examine the background setting that led to the deadly tornado. Several other tornado days in the same general area with synoptic patterns similar to the Joplin tornado day also are examined from the standpoint of environmental parameters for comparison. The results show the Joplin tornado case to be an example of very supportive ingredients developing from a favorable evolution of synoptic-scale features; similar patterns have produced several deadly tornadoes in recent years. A couple of mesoscale boundaries also may have contributed to increased tornado potential in the Joplin area. Informal comments published elsewhere have described the environment for this event as “unfavorable” for violent tornadoes. The findings here contradict and refute that characterization, and show that the background environment for the Joplin tornado was actually quite favorable for supporting strong or violent tornadoes.

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Katurji, M., B. Khan, M. Sprenger, R. Datta, K. Joy, P. Zawar-Reza, and I. Hawes. "Meteorological Connectivity from Regions of High Biodiversity within the McMurdo Dry Valleys of Antarctica." Journal of Applied Meteorology and Climatology 58, no. 11 (November 2019): 2437–52. http://dx.doi.org/10.1175/jamc-d-18-0336.1.

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AbstractMeteorological connectivity between biological hot spots of the McMurdo Dry Valleys (MDVs) of Antarctica is thought to play a role in species distribution and abundance through the aeolian transport of bioaerosols. Understanding the potential role of such meteorological connectivity requires an understanding of near-surface wind flow within and between valley airsheds. To address this, we applied Lagrangian wind trajectory modeling to mesoscale (spatial resolution of ~1 km) weather model output to predict connectivity pathways, focusing on regions of high biodiversity. Our models produce maps of a likelihood metric of wind connectivity that demonstrate the synoptic and mesoscale dependence of connections between local, near-local, and nonlocal areas on wind transport, modulated by synoptic weather and topographic forcing. These connectivity areas can have spatial trends modulated by the synoptic weather patterns and locally induced topographically forced winds. This method is transferrable to other regions of Antarctica for broader terrestrial, coastal, and offshore ecological connectivity research. Also, our analysis and methods can inform better placement of aeolian dust and bioaerosol samplers in the McMurdo Dry Valleys, provide preliminary guidelines behind the meteorological controls of sediment transport and smaller particle distribution, and present quantifiable knowledge informing new hypotheses around the potential of wind acting as a physical driver for biological connectivity in the MDVs.

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van Schalkwyk, Lynette, and Liesl L. Dyson. "Climatological Characteristics of Fog at Cape Town International Airport." Weather and Forecasting 28, no. 3 (June 1, 2013): 631–46. http://dx.doi.org/10.1175/waf-d-12-00028.1.

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Abstract The character of fog at Cape Town International Airport (CTIA), South Africa, is investigated, using 13 yr of historical hourly data during the period 1997–2010. Hourly surface observations are used to identify fog types that most frequently affect CTIA, by using an objective fog-type classification method that classifies fog events according to their primary formation mechanisms. Fog-type characteristics, such as the minimum visibility, duration, and time of onset and dissipation, are determined. Self-organizing maps (SOMs) are used to determine the dominant synoptic circulation types associated with fog at CTIA. Results show that radiative processes are the most common cause of fog, with an enhanced likelihood of radiation fog in winter. Cloud-base-lowering fog and advection fog events are more likely at the start of the fog season. As the fog season (March–August) progresses, synoptic circulations associated with fog change from a dominant low pressure pattern along the west coast in March and April to a dominant interior high pressure pattern toward July and August. The techniques presented may be used to provide aviation forecasters with a detailed description of the types of fog that frequently occur, their characteristics, and the synoptic circulation associated therewith.

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Journal articles on the topic 'Synoptic maps'

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