Soil, Environmental and Atmospheric Sciences publications (MU)
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Item A review of Bayesian belief network models as decision-support tools for wetland conservation : are water birds potential umbrella taxa?(2018) MacPherson, Maggie P.; Webb, Elisabeth B.; Raedeke, Andrew; Mengel, Doreen; Nelson, FrankCreative approaches to identifying umbrella species hold promise for devising effective surrogates of ecological communities or ecosystems. However, mechanistic niche models that predict range or habitat overlap among species may yet lack development. We reviewed literature on taxon-centered Bayesian belief network (BBN) models to explore a novel approach to identify umbrella taxa identifying taxonomic groups that share the largest proportion of habitat requirements (i.e., states of important habitat variables) with other wetland-dependent taxa. We reviewed and compiled published literature to provide a comprehensive and reproducible account of the current understanding of habitat requirements for freshwater, wetland-dependent taxa using BBNs. We found that wetland birds had the highest degree of shared habitat requirements with other taxa, and consequently may be suitable umbrella taxa in freshwater wetlands. Comparing habitat requirements using a BBN approach to build species distribution models, this review also identified taxa that may not benefit from conservation actions targeted at umbrella taxa by identifying taxa with unique habitat requirements not shared with umbrellas. Using a standard node set that accurately and comprehensively represents the ecosystem in question, BBNs could be designed to improve identification of umbrella taxa. In wetlands, expert knowledge about hydrology, geomorphology and soils could add important information regarding physical landscape characteristics relevant to species. Thus, a systems-oriented framework may improve overarching inferences from BBNs and subsequent utility to conservation planning and management.Item Climatological Features of blocking anticyclones in the Northern Hemisphere(Munksgaard, 1994) Lupo, Anthony R., 1966-; Smith, Phillip J.; University of Missouri-Columbia. College of Agriculture, Food and Natural Resources (CAFNR). School of Natural Resources. Department of Soil, Environmental and Atmospheric Sciences.Blocking anticyclones have long been of interest to the atmospheric science community because of their profound effect on local and regional climates. Previous climatologies of blocking anticyclones have been performed using subjective or objective techniques to locate individual blocking events using observational data sets typically of greater than lO years. In this study, a 3-year climatology of Northern Hemisphere blocking anticyclones was developed using ECMWF analyses to derive a comprehensive set of blocking anticyclone characteristics, including location, frequency, duration, intensity, size, seasonal and regional distribution, and relationship to precursor cyclones and jet streaks. Results show that preferred blocking regions were located over the eastern Atlantic Ocean, the Pacific Ocean, and the Ukraine/western Russia and that most blocks occurred in winter, as seen in other climatological studies. Block half- wavelengths, which averaged about 3000 km, were positively cQrrelated with block intensity at the 99% confidence level. However, block duration, which averaged 8.6 days, was only weakly correlated with both size and intensity. Also, this study reveals that all 63 blocking anticyclones were preceded by an identifiable surface cyclone, which began its most rapid deepening 36 h or more prior to block onset. However, only 34 of these cyclones could be characterized as "explosively" developing, with half of these preceding winter season blocks and none preceding summer season blocks. A positive correlation was found between the intensity of blocking anticyclones and the intensity of the precursor cyclone development, significant at the 95 % confidence level. This correlation was also found for events occurring over the oceanic regions. Finally, the intensity of the precursor cyclone development was correlated with other blocking characteristics and no significant relationships were found.Item Climatological features of blocking anticyclones: a study of Northern Hemisphere CCM1 model blocking events in present-day and double CO2 concentration atmospheres(Springer-Verlag, 1997) Oglesby, R. J.; Mokhov, Igor I.; Lupo, Anthony R., 1966-; University of Missouri-Columbia. College of Agriculture, Food and Natural Resources (CAFNR). School of Natural Resources. Department of Soil, Environmental and Atmospheric Sciences.Using output made with the National Center for Atmospheric Research (NCAR) Community Climate Model Version 1 (CCM1), the characteristics of blocking events over the Northern Hemisphere in a ten-year present day control simulation with a CO2 concentration of 330 ppm were compared to those in a previously analyzed observational three-year climatology. The characteristics of blocking events in a double present-day CO2 concentration simulation were then compared to those in the control simulation in order to evaluate how these characteristics might change in an increased CO2 atmosphere. The results demonstrated that in the Northern Hemisphere the CCM1 correctly simulated many characteristics of blocking events such as average annual number of occurrences, annual variations is size and intensity, and preferred formation regions. A more detailed analysis (i.e., by region and season) revealed some di¤erences between the CCM1 and observed blocking events for characteristics such as mean frequency of occurrence, intensity, size and duration. In addition, the model failed to capture adequately the occurrence of blocking events over the western Asian continent. A comparison of the double CO2 concentration run to the control showed that, in general, blocking events were more persistent and weaker, but of similar size in the increased CO2 atmosphere. Also, some statistically signiÞcant regional and seasonally dependent changes were found in the frequency of occurrence, duration, and intensity. Finally, a correlation between block size and intensity, signiÞcant at the 99% conÞdence level, was found in each climatology. This result is similar to a correlation found in the analysis of observations.Item The Variability in Atlantic Ocean Basin Hurricane Occurrence and Intensity as related to ENSO and the North Pacific Oscillation(National Weather Association, 2000-06) Lupo, Anthony R., 1966-; Johnston, Grant; University of Missouri-Columbia. College of Agriculture, Food and Natural Resources (CAFNR). School of Natural Resources. Department of Soil, Environmental and Atmospheric Sciences.The investigation of the effect of El Niño-related variability on hurricane activity has been a popular topic of study. Studies have shown that there are fewer Atlantic Ocean basin hurricanes during an El Nino year than during a La Nina year. Various atmospheric and oceanic parameters that influence hurricane development become significantly altered during an El Niño event, leading to suppressed easterly wave development and growth. The effect of the El Niño/La Niña cycle on hurricane intensity, however, is not straightforward. Studies addressing the interannual variability of hurricane intensity have captured far less attention than the more generalized subject of hurricane occurrence. This study examined the interannual variability of hurricane intensity (measured as wind speed and interpreted through the Saffir-Simpson Scale) from 1938 through 1999. These data were then compared with the occurrence of El Niño/La Niña events as defined using the Japan Meteorological Association (JMA) index. El Nino/La Nina variability superimposed on variability associated with the North Pacific Oscillation (NPO) was also examined here. Not surprisingly, during an El Niño year the intensity of Atlantic hurricanes was found to be weaker than during a neutral year or a La Niña year. There were also significant differences found in hurricane intensity between El Nino and La Nina years when the NPO was in phase 1, rather than when the NPO was in phase 2. Finally, this study also examined the interannual variation in hurricane intensity by genesis region (i.e. the eastern and western Atlantic Ocean Basins, the Caribbean, and the Gulf of Mexico).Item The Wintertime Southern Hemisphere Split Jet: Structure, Variability, and Evolution(American Meteorological Society, 2001-11) Lupo, Anthony R., 1966-; Atallah, Eyad H.; Cempa, Michael J.; Wasula, Thomas A.; Bosart, Lance F.; Bals-Elsholz, Teresa M.; University of Missouri-Columbia. College of Agriculture, Food and Natural Resources (CAFNR). School of Natural Resources. Department of Soil, Environmental and Atmospheric Sciences.A persistent feature of the Southern Hemisphere upper-level time-mean flow is the presence of a split jet across the South Pacific east of Australia during the austral winter. The split jet is composed of the subtropical jet (STJ) on its equatorward branch and the polar front jet (PFJ) on its poleward branch. The NCEP-NCAR reanalysis is used to investigate the structure and evolution of the split jet. Results show that the presence/absence of the PFJ determines the degree of split flow, given that the STJ is a quasi-steady feature. A split-flow index (SFI) is developed to quantify the variability of the split jet, in which negative values represent strong split flow and positive values nonsplit flow. Correlations with teleconnection indices are investigated, with the SFI positively correlated to the Southern Oscillation index and negatively correlated to the Antarctic oscillation. The SFI is used to construct composites of heights, temperature, and wind for split-flow and non-split-flow days. The composites reveal that relatively cold conditions occur in the South Pacific in association with non-split-flow regimes, and split-flow regimes occur when relatively warm conditions prevail. In the latter situation cold air bottled up over Antarctica helps to augment the background tropospheric thickness gradient between Antarctica and the lower latitudes with a resulting increase in the thermal wind and the PFJ. It is surmised that frequent cold surges out of Antarctica moving into the South Pacific are associated with non-split-flow regimes. In this context, the variability of the split jet responds to large-scale baroclinic processes and is further modulated by synoptic-scale disturbances.