Differential responses of vegetation phenology to climatic elements during extreme events on the Chinese loess plateau.

Extreme, dry events have major impacts on vegetation phenology worldwide. However, the differential responses of vegetation phenology to climatic elements during these extreme events remain unclear. We investigated the response of vegetation phenology to climatic factors during extreme events in arid and semi-arid regions of the Chinese Loess Plateau, using the climate water deficit method, to identify extremely dry and wet events. The results revealed that extremely wet events extended the vegetation growth periods in addition to global warming, whereas extremely dry events did not completely counteract this effect. During different extreme events, phenological changes in vegetation on the Loess Plateau were primarily influenced by the interactive effects of climatic factors. During extremely dry events, a 100 mm increase in precipitation advanced the start of the season by 3.0, 9.2, and 16.7 days in forest, shrubland, and grassland, respectively. During extremely wet events, a 1 °C rise in temperature delayed the end of the season by 1.6, 0.6, and 3.8 days in forest, shrubland, and grassland, respectively. These findings provide crucial guidance for improving predictions of plant phenology changes under extreme climatic events and unraveling biosphere-atmosphere feedback cycles.

Non-parametric tests and multivariate analysis applied to reported dengue cases in Brazil.

Dengue is among the largest public health problems in Brazil. Reported dengue cases via DATASUS were correlated with reanalysis data from NCEP (rainfall and air temperature) and Brazil's population data (2000 and 2010) from 1994 to 2014. The aim of this study was to evaluate relational patterns between climate variables together with population data from the last census and reported cases of dengue in Brazil from 1994 to 2014 by using statistical techniques. Several statistical methods [descriptive and exploratory statistics; simple and multiple linear regressions; Mann-Kendall (MK), Run, and Pettit nonparametric tests; and multivariate statistics via cluster analysis (CA)] were applied to time series. The highest percentages of Dengue cases were in Brazil's Southeast (47.14%), Northeast (29.86%), and Central West (13.01%). Upon CA of the Brazilian regions, three homogeneous dengue groups were formed: G1 (North and Central West), G2 (Southeast and Northeast), and G3 (South). Run testing indicated that the time series is homogenous and persistence free. MK testing showed a nonsignificant trend of increase of dengue cases in 23 states with positive trends and in four states with negative trends of Brazil. A significant increase in the magnitude of dengue at the regional level was recorded in the North, Southeast, South, and Central West regions. Statistical methods showed that dengue variability in Brazil is cyclical (2- to 3-year cycles), but not repetitive of El Niño-Southern Oscillation (ENSO) in the moderate, strong, and neutral categories. ENSO interferes with the action of weather systems, changing or intensifying rainfall and air temperatures in Brazil. The population increase in recent decades and the lack of effective public policies together with the action of ENSO contributed to the increase in dengue cases reported in Brazil.

Non-parametric tests applied to reported cases of dengue in the southeast region of Brazil / Testes não-paramétricos aplicados a casos de dengues reportados na região sudeste do Brasil

Dengue is one of the biggest problems of global public health in developing and underdeveloped countries. Nowadays, researchers in climate changes are concerned about the impact of these changes on human health, particularly with increased this epidemic. Dengue is among the largest public health problems in Brazil and is higher in the months with high temperatures, which is the Aedes aegypti's reproductive period climax. Reported dengue cases via DATASUS from 1994 to 2014 were analyzed. Mann-Kendall (MK), Run and Pettit nonparametric tests; were applied to time series. The run test indicated that the time series is homogenous and persistence free. There is a non-significant trend of increase of a number of reported dengue cases only in Rio de Janeiro. Based on the test, three positive trends were identified in the time series of São Paulo, Minas Gerais and the Espírito Santo States of dengue cases reported in Southeast of Brazil. Pettitt test was able to identify the years classified as El Niño events and that had a significant impact on the increase of dengue cases in the southeastern region of Brazil.

A dengue é um dos maiores problemas de saúde pública global em países em desenvolvimento e subdesenvolvidos. Hoje em dia, os pesquisadores em mudanças climáticas estão preocupados com o impacto dessas mudanças na saúde humana, particularmente com o aumento dessa epidemia. A dengue está entre os maiores problemas de saúde pública no Brasil e é maior nos meses com altas temperaturas, que é o clímax do período reprodutivo do Aedes Aegypti. Foram analisados relatórios de casos de dengue via DATASUS de 1994 a 2014. Testes não paramétricos de Mann-Kendall (MK), Run e Pettit; foram aplicadas em séries temporais. O teste Run indicou que a série temporal é homogênea e sem persistência. Existe uma tendência não significativa de aumento do número de casos de dengue relatados apenas no Rio de Janeiro. Com base no teste, três tendências positivas foram identificadas na série temporal de casos de dengue de São Paulo, Minas Gerais e Espírito Santo relatados no Sudeste do Brasil. O teste de Pettitt foi capaz de identificar os anos classificados como eventos de El Niño e que tiveram um impacto significativo no aumento de casos de dengue na região sudeste do Brasil.

Desempenho de métodos de estimativa da evapotranspiração de referência nas localidades de Frederico Westphalen e Palmeira das Missões, RS / Perfomance of methods for estimating reference evapotranspiration in the municipalities of Frederico Westphalen and Palmeira das Missões, State of Rio Grande do Sul, Brazil

A estimativa da evapotranspiração de referência (ETo), usada no balanço hídrico, possibilita quantificar o armazenamento de água no solo, auxiliando no manejo da irrigação. O objetivo do trabalho foi comparar métodos mais simples de estimativa da evapotranspiração de referência com o método Penman-Monteith (FAO), nas escalas diária e de 5, 10, 15 e 30 dias, e mensal, para os municípios de Frederico Westphalen e Palmeira das Missões, no RS. Os métodos avaliados tenderam a melhorar a eficiência com o aumento da escala temporal de estudo, mantendo o mesmo desempenho para ambas as localidades. Os maiores e menores valores de ETo ocorreram nos meses de dezembro e junho, respectivamente. A maioria dos métodos subestimou os valores de ETo. Em qualquer escala temporal, os métodos de Makking e da Radiação FAO24 podem substituir o modelo de Penman-Monteith.

The estimation of reference evapotranspiration (ETo), used in water balance, allows to determine soil water content, assisting on irrigation management. The present study aimed to compare simple ETo estimating methods with the Penman-Monteith (FAO), in the folowing time scales: daily, 5, 10, 15 and 30 days and monthly in the counties of Frederico Westphalen and Palmeira das Missões, in the Rio Grande do Sul state, Brazil. The methods tested had their efficiency improved by increasing the time scale of analysis, keeping the same performance for both locations. The highest and lowest ETo values occurred in December and June, respectively. Most methods underestimated ETo. For any of the time scales Makking and Radiaton FAO24 methods can replace the Penman-Monteith for estimating ETo.