Impacts of the Madden‐Julian oscillation on intraseasonal precipitation over Northeast Brazil

Valadão, Cati E. A.; Carvalho, Leila M. V.; Lúcio, Paulo Sérgio; Chaves, Rosane Rodrigues

doi:10.1002/joc.4818

Cited by 29 publications

(18 citation statements)

References 91 publications

(232 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…5, 6, 7). These results are consistent with those of (Valadão et al 2017;Alvarez et al 2016), who use station data and gridded station data, respectively, to demonstrate the seasonality of MJO teleconnections to precipitation in South America.…”

Section: South Americasupporting

confidence: 89%

MJO teleconnections to crop growing seasons

Anderson¹,

Muñoz²,

Goddard³

et al. 2020

Clim Dyn

View full text Add to dashboard Cite

While many Madden-Julian Oscillation (MJO) teleconnections are well documented, the significance of these teleconnections to agriculture is not well understood. Here we analyze how the MJO affects the climate during crop flowering seasons, when crops are particularly vulnerable to abiotic stress. Because the MJO is located in the tropics of the summer hemisphere and maize is a tropical, summer-grown crop, the MJO teleconnections to maize flowering seasons are stronger and more coherent than those to wheat, which tends to be grown in midlatitudes and flowers during the spring. The MJO significantly affects not only daily average precipitation and soil moisture, but also the probability of extreme precipitation, soil moisture and maximum temperatures during crop flowering seasons. The average influence on the probability of extreme daily precipitation, soil moisture, and maximum temperature events is roughly equal. On average the MJO modifies the probability of a 5th or 95th, 10th or 90th, and 25th or 75th percentile event by ∼ 2.5%, ∼ 4% and ∼ 7%, respectively. This means that an exceptionally dry (10th percentile) soil moisture value, for example, would become ∼ 40% more common (happening 14% of the time) during certain MJO phases. That the MJO can simultaneously dry soils and raise maximum air temperatures may be particularly damaging to crops because without available soil water during times of heat stress, plants are unable to transpire to cool leaf-level temperatures as a means of avoiding long-term damage. As a result, even though teleconnections from the MJO last only a few days to a week, they likely affect crop growth.

show abstract

Section: South Americasupporting

confidence: 89%

MJO teleconnections to crop growing seasons

Anderson¹,

Muñoz²,

Goddard³

et al. 2020

Clim Dyn

View full text Add to dashboard Cite

show abstract

“…According to the literature, it is known that rainfall distribution in the NEB is not typical of equatorial areas in terms of volume, because different physical mechanisms are responsible for a remarkable interannual (Marengo and Bernasconi, ; Vieira et al ., ) and occasional intraseasonal variability (Valadão et al ., ), which result in three climate types: tropical, subtropical humid, and semiarid (Cavalcanti et al ., ). Figure shows the mean monthly accumulated rainfall in each capital city of the NEB in the period from 1988 to 2017 and allows the identification of some of these climate characteristics as well as the association with the occurrence of meteorological phenomena.…”

Section: Resultsmentioning

confidence: 99%

What is the return period of intense rainfall events in the capital cities of the northeast region of Brazil?

Oliveira

Lima

2019

Atmospheric Science Letters

View full text Add to dashboard Cite

The northeast of Brazil is characterized by a semiarid climate, in which there is a considerable temporal and spatial variability in the distribution of rainfall. In this region, the occurrence of intense rainfall events (IREs) causes severe damage to the population, given that the rampant urbanization and land use processes make cities more susceptible to harmful consequences. Thus, the objective of this study is to estimate the period and the level of return of IREs in the capital cities of the northeast Brazil. For that end, observed data from weather stations of the National Institute of Meteorology for the period from 1988 to 2017 were used. We defined thresholds based on the excesses above the mean and inserted the data in the generalized Pareto distribution in order to obtain diagnostics of future estimates. Results showed that return periods were surpassed in seven of the nine capital cities in 2018. Furthermore, the estimates for IREs with a return period of 5, 10, and 100 years were higher if compared to the return period of 1 year. The results found in this study are extremely relevant for the understanding of the occurrence of these events and also serve as a tool for decision-making and the elaboration of policies aimed at minimizing the impacts of such events. K E Y W O R D S extreme value theory, generalized Pareto distribution, natural disasters

show abstract

“…(Waliser, Murtugudde, Strutton, & Li, 2005) have found that Chlorophyll-a can vary at Madden-Julian Oscillation (MJO) time scales. MJO is an eastward moving strong contributor to various extreme events of rainfall, winds, clouds, and pressure that traverses in the tropics (Drushka et al, 2012;Valadão, Carvalho, Lucio, & Chaves, 2017). The is found to be influenced by the atmospheric variability, with periods of 30-60 days and eastward propagation of atmospheric convection cells (Hendon & Salby, 1994).…”

Section: Boosted Regression Treesmentioning

confidence: 99%

Environment regime influence on Chlorophyll-a abundance and distribution in North Indian Ocean

Elepathage

Tang

2019

Preprint

View full text Add to dashboard Cite

North Indian Ocean region around India and Sri Lanka is a complex and rich coastal ecosystem undergoing various seasonal and inter-annual changes and various pressures. Hence the objective of this study was to assess the scales of coupling between chlorophyll-a concentration (chl-a) and the influencing variables and explore the nature of the spatiotemporal variability of them. The seasonal and annual variations of chl-a along the Bay of Bengal (BoB), Arabian sea (AS) and ocean region around Sri Lanka in relation to the physical and chemical oceanographic variables were analyzed using satellite observations covering the period of 2002-2018. The effects of diffuse attenuation coefficient, photosynthetically available radiation (PAR), sea surface temperature (SST), Wind speed, Eastward wind component, Nitrate, Black carbon column mass density, Sea Salt Surface Mass Concentration, Open water net downward longwave flux, Surface emissivity were considered on a monthly time scale. Wavelet analysis and the Boosted Regression Trees (BRT) were used as the main analysis and modeling methods. The peaks of chl-a, diffuse attenuation coefficient, and nitrate were observed in September. In wind speed and eastward wind it was July and in black carbon column mass density, and PAR in March. In Sea Salt Surface Mass Concentration, Open water net downward longwave flux, Surface emissivity, Diffuse attenuation coefficient for downwelling irradiance, and SST mean maximums were found in June, February, November, September, April respectively. In BRT model the estimated cross validation (cv) deviance, standard error (se), training data correlation, cv correlation, and D2 were 0.003, 0.002, 0.932, 0.949, and 0.846 respectively. According to the results, diffuse attenuation coefficient (90%), eastward wind component (3.7%) and nitrate (3%) were the most positively correlated variables with Chl-a occurrence. SST evidenced an inverse relationship with Chl-a. According to the model built <42 Einsteinm-2day-1 PAR, <0.986 surface emissivity, <70 Wm-2 open water net downward long wave flux, 28.2 -28.5 0C SST , 2 ms-1 Wind speed, 5 ms-1 - 6 ms-1 eastward wind, 4.8 x10-8 -7x10-8 kgm-3 sea salt surface mass concentration, and 0.1-0.5micromoleL-1 nitrate are favourable for the optimum level of phytoplankton occurrence. Since BRT deals robustly with non-linear relationships of the environmental variables it can be used in further studies of ecological modeling.

show abstract

Impacts of the Madden‐Julian oscillation on intraseasonal precipitation over Northeast Brazil

Cited by 29 publications

References 91 publications

MJO teleconnections to crop growing seasons

MJO teleconnections to crop growing seasons

What is the return period of intense rainfall events in the capital cities of the northeast region of Brazil?

Environment regime influence on Chlorophyll-a abundance and distribution in North Indian Ocean

Contact Info

Product

Resources

About