Navegando por Assunto "Rainfall"

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Acesso aberto (Open Access)
Avaliação quantitativa da dinâmica espaço-temporal da precipitação na região hidrográfica Tocantins-Araguaia
(Universidade Federal do Pará, 2012-01-31) LOUREIRO, Glauber Epifanio; FERNANDES, Lindemberg Lima; http://lattes.cnpq.br/4641468846318922
The analysis of the rainfall behavior in a watershed is fundamental for engineering and management of the hydric resources. The Tocantins-Araguaia Basin (TAB) for your recent occupation and economic potentialities, earns prominence in the national scenery. This work evaluates the spatial-temporal dynamics of the annual precipitation in this region quantitatively during a period of 30 years of data. The dynamics of rainfall can be analyzed by the calculation of the mean precipitation in a given area, by composing isohyets maps of annual precipitation. However, the confection of these maps require one interpolation method what better please represent the rainfall characteristics in places not shown for posterior please analyze quantitative of the behaviour of the rainfall. For much, went realized descriptive exploratory analyses sample and spatial how requisition of stationarity of the interpolation method geostatistics, fill and validation of the theoretical model what he embed to the variograma of annual rainfall. The confection of isohyets maps for the method of ordinary kriging (no drift) and Universal Kriging (drift) went afterwards realized the calculation of the precipitate volume in the hydrographic region for the method of the contours. The spatial dynamics of the precipitation was realized with base in the analysis of descriptive statistics, isohyets maps, map hypsometric, Meteorological Irregularity (MI) and Coefficient Variation. Temporal dynamics was analyzed by the distribution of the total annual of volumetric precipitation for every secondary basin of the TAB, Standarized Anomaly, in the variation interanual of precipitation and trend test and magnitude represented respectively by Mann Kendall Test and Sen's. Interrelated upshots with the meteorological anomalies of the Atlantic Ocean (Dipole) and Pacific (ENOS) indicate the behaviour of the enough precipitation heterogeneous and with big variability principally in the under subbasin Tocantins Alto (TOA) (14%.) Diminution of the pluviometric amplitude, in years of intense meteorological anomaly causing a precipitation increment to the south of the under basins TOA and Araguaia (ARA) and diminution of the precipitation to the north of the secondary subbasin Tocantins Baixo (TOB), in El Niño events. One cannot prove for Mann Kendall test precipitate in the TAB, has an trend significative statistically in the volume but the estimated Sen's gives clues of fall in the precipitation in the sub-basin TOA (-1,24 km³/year) and Araguaia (ARA) (-1,13 km³/year) and increase of the precipitation in the under basin TOB (0,53 Km³/year) and for the TAB (-1,5 km³/year). So spatial and temporal variability in the under basins is intimately reported to the events of meteorological anomaly, in which your action occurs of irregular way to the long of the area to study and lop influence the socioeconomic different activities in the TAB in accordance with your magnitude and area of occurrence.
Acesso aberto (Open Access)
Distribuição espaço-temporal da comunidade zooplanctônica no estuário do Taperaçu (Bragança-Pará-Brasil): biomassa e produção secundária das principais espécies de copépodos
(Universidade Federal do Pará, 2016-10-25) LEITE, Natália da Rocha.; MONTES, Manuel de Jesus Flores; http://lattes.cnpq.br/2999296486918048; COSTA, Rauquírio André Albuquerque Marinho da; http://lattes.cnpq.br/4504677939464624; https://orcid.org/0000-0003-4461-3936
This study aimed to determine the composition and distribution of zooplankton in the estuary Taperaçu evaluating, in temporal and spatial scales, the contribution of the main species of copepods for biomass and production in terms of organic carbon in the environment under study. Therefore, samples were taken bimonthly (zooplankton and hydrologic variables) from June 2012 to June 2013, in three fixed stations located along the estuary, totaling 45 samples. The zooplankton community was apparently homogeneous. With regard to biological attributes, significant variations related to circadian cycles (day/night) and tidal periods (flood/ebb) were not detected. High values of abundance of Paracalanus quasimodo, Labidocera fluviatilis and Pseudodiaptomus marshi were observed. The absence of a nichtemeral and tidal patterns, was possibly related to the morphodynamic characteristics of the estuary Taperaçu, such as the presence of sandbanks in its central portion, the absence of a river discharge, the small catchment area, low depths and strong tidal currents, which facilitate the processes of horizontal and vertical mixing of the water column. When analyzed on a monthly and spatial scale, it was observed the influence of seasonal periods on the dynamics of these organisms, these being directly related to variations in salinity, turbidity and chlorophyll-a concentrations. The zooplankton community was dominated by copepods, especially Acartia tonsa (22,230.9±46,145.7 ind.m ), Acartia lilljerborgi (4,011.6±10,326.5 ind.m -3 ), P. quasimodo (9,270.7±17,593.3 ind.m -3 ), P. marshi (3,267.3±4,565.1 ind.m-3) and Oithona oswaldocruzi (30,221.9±28,328.4 ind.m-3-3), together with Oikopleura dioica (15,284.6±26,060.6 ind.m-3). The average diversity of species ranged from 2.0±0.6 bits.ind-1 to 3.8±0.4 bits.ind-1, while the evenness ranged from 0.5±0.1 to 0.7±0:03. Overall, the temporal variability (monthly and temporal) and spatial observed in the structure and dynamics of zooplankton population was mainly related to fluctuations in precipitation rates, which directly affect the salinity of the water and consequently the abundance of these organisms. In addition, it was also concluded that the presence of typically marine species such as P. quasimodo and O. dioica may be related to the significant increase in salinity as a result of reduced rainfall in 2012. Biomass and production A. tonsa and A. lilljeborgi were directly related to the local rainfall since, A. tonsa showed high values throughout the period, not only in the rainy season as previously observed in this same estuary. The immature stages (C1-C5) of A. tonsa were the dominant forms, especially the C4 stage (839.88±1518.80 mgC.m), while for A. lilljeborgi the highest values were obtained for adults (1,347.84±499.95 mgC.m-3). The obtained rates of secondary production were higher than those described for other estuaries located around the world, and these results are associated with the high temperatures recorded during the year as well as the observation of water rich in nutrients and particulate organic matter derived from adjacent to mangroves Taperaçu. In general, the results indicate that the influence of climate changes on the hydrological variables especially temperature, salinity, as well as the concentration of chlorophyll-a were the main responsible for the dynamics of mesozooplanctônicas species identified in the estuary of Taperaçu.