Ciência e Natura

Analysis of meteorological conditions in the municipality of Palhoça/SC by a low-cost station with data transmitted via public lighting telemanagement

2024-07-11T09:52:25-03:00

Smart cities have a remote management system capable of monitoring various information via the public lighting system. It should be noted that environmental data is already collected via this system in other countries, but this initiative has not yet been implemented in Brazil. Thus, this project proposed installing a low-cost station in Palhoça/SC, transmitting data continuously, through the public lighting telemanagement system, to a storage platform and comparing the information obtained with professional meteorological stations nearby. In this solution, temperature and atmospheric pressure data were analyzed over a short period, highlighting three distinct meteorological conditions. The proposal is to implement several stations throughout the municipality in the future, generating information for regional meteorological analyses.

Analysis of tropospheric ozone climatology in Santa Maria - RS from OMI/MLS instruments

2025-01-30T18:07:07-03:00

Ozone (O3) is an important trace gas in the atmosphere and one of the main elements of pollution in the tropospheric region. This work aims to analyze the behavior and trends of the tropospheric ozone column (O₃trop) in the city of Santa Maria, Rio Grande do Sul, Brazil (29.42°S and 53.41°W) between 2005 and 2020, using data from the Ozone Monitoring Instrument (OMI) and Microwave Limb Sounder (MLS) instruments on board the AURA satellite, applying the Tropospheric Ozone Residual (TOR) technique. The results revealed a well-defined annual cycle, with minimum values in winter and maximum values in spring, in addition to an increasing trend of 2.3% per decade; high O₃trop concentrations occurred in periods with the action of the La Niña phenomenon. Wavelet analysis highlighted significant interannual influences, associated with phenomena such as the El Niño Southern Oscillation (ENSO) and the Quasi-Biennial Oscillation (QBO).

Climatology of tornado occurrences in southern Brazil

2024-06-24T17:23:03-03:00

The subtropical sector of South America east of the Andes, including southern Brazil, is frequently affected by severe convective storms. In some situations, atmospheric ingredients conducive to the occurrence of tornadoes are also observed. However, despite the potential for the formation of this hazardous weather phenomenon, the documentation of tornadoes in southern Brazil is poor compared to other regions around where consolidated severe weather databases exist (e.g., USA and Europe). This work leveraged different existing sources of information to generate a database of tornado occurrences covering southern Brazil, Uruguay, Argentina and Paraguay. These sources encompass tornado footage and photographs, or visual documentation of wind damage consistent with tornadic activity, available in traditional media and social networks. Additional sources include tornado events existing in the scientific literature and non-scientific initiatives that keep tornado reports. Tornado damage tracks identified through high resolution environmental satellite imagery were also included as a source of information. Such compilation produced a tornado database with 310 occurrences in southern Brazil. This study emphasizes the spatial, seasonal and annual distributions of the tornado occurrences in addition to the human impacts in terms of injuries and fatalities. The sector displaying highest frequency of tornado events was identified for an area encompassing northern Rio Grande do Sul, western Santa Catarina and southwestern Paraná states, with peak activity during winter.

Trends in convective parameters in southern Brazil: a preliminary analysis

2024-07-29T15:19:19-03:00

This study is a preliminary investigation, for southern Brazil, about possible changes in the last four decades in the magnitude of two convective parameters indicative of atmospheric environments favorable to severe convective storms. The parameters selected for this research, the convective available potential energy (CAPE), and the magnitude of the vector wind difference between the surface and 6 km above ground level (DLS), are, respectively, indicative of the presence of conditional instability and vertical wind shear in a deep layer. These parameters were computed for hourly tropospheric profiles (or pseudo-soundings) extracted from the native vertical grid of the ERA5 reanalysis for the period between 1980 and 2021 for the grid points nearest to the three state capitals of southern Brazil: Curitiba, Florianópolis and Porto Alegre. The analysis, for each location, of the trend in the time series of CAPE and DLS, averaged for every single month, was carried out with the aid of the non-parametric Mann-Kendall test. The results obtained from the tropospheric profiles of the ERA5 reanalysis reveal a negative trend in the extreme values of CAPE, especially for Porto Alegre, but accompanied by an increase in the magnitude of DLS for all locations. Therefore, in this preliminary analysis, the implications from CAPE and DLS for the conditioning of environments favorable to severe storms display opposite signs for the selected locations. Additional research addressing the frequency of environments conducive to severe storms is needed for a more complete assessment of the impact of these trends.

Precipitation extremes during the soybean planting period in the MATOPIBA region

2023-12-19T12:28:51-03:00

This work aims to analyze the variability of extreme consecutive dry days (CDD) and wet days (CWD) during the soybean planting period (October-November-December) in the MATOPIBA region from 1980 to 2019. Daily precipitation data from Xavier et al. (2022) was used, with a spatial resolution of 0.1° x 0.1° and a temporal resolution from 1980 to 2019. The extreme climate indices used (CDD and CWD) were defined by the ETCCDI (Expert Team on Climate Change Detection and Indices) and statistical techniques were applied for a better understanding of precipitation variability in the region of interest. Among the main results, an increasing (decreasing) trend of 1 to 3 (1 to 2) days/decade in CDD (CWD) events in October was observed, along with an increasing trend (2 days/decade) in CDD events in December. These results may imply a delay in the implementation of the harvest (October) and a water deficit during the plant’s vegetative period, due to irregularities in December rainfall. Furthermore, there was a strong influence of the El Niño Southern Oscillation phenomenon on precipitation indices, serving as an additional limiting factor in rainfall distributions in MATOPIBA.

Comparative analysis of meteorological data from Rio Brilhante MS: INMET station, BR-DWGD database and ERA5 reanalysis

2024-10-09T13:30:14-03:00

Considering agriculture as one of the main economic poles in Brazil, the state of Mato Grosso do Sul is an important center of agricultural and livestock production. Studying the climate during all months of the year, identifying the most critical periods, is of great importance for agriculture in the region, and can provide valuable information for decision-making and risk reduction. The objective of this work is the comparison between the data observed in the surface meteorological station and of two different databases, ERA5 and BR-DWGD. Daily data were used and the variables of temperature (mean, maximum and minimum, in ºC) and precipitation (mm) occurred in the twelve months of the year in the period from 2009 to 2022, from station A743 of the National Institute of Meteorology (INMET), installed at Rio Brilhante, Mato Grasso do Sul, Brazil (21,775°S, 54,528°W and 324.31 m altitude) and Reanalysis data from the ERA5 global model and the BR-DWGD data. The results of the comparison between the databases and the observed data showed that the precipitation values have low correlation and greater variation with the observed data, although the BR-DWGD has a correlation of 0.83. Temperature values showed values between 0.8 and 1 in both databases. Thus, the BR-DWGD database is more suitable for the climate analysis of the study region.

Sensitivity of an unusual cyclone in South America to convective parameterization schemes in RegCM5

2023-09-21T11:17:14-03:00

Raoni storm (2021) was a remarkable and unusual cyclone that developed on the Atlantic coast of southern South America. This study evaluates the performance of different parameterization schemes with the RegCM5 model in simulating the evolution of Raoni. Results show that the Tiedtke convective scheme has the best performance in representing the evolution of the cyclone in terms of position, intensity and duration, though the maximum intensities are underestimated with respect to ERA5 reanalysis. The cyclone growth and its initial propagation are fairly well represented by the Emanuel scheme, but the cyclone dissipates too early. In the Grell scheme, the cyclone moved southeastward and then a new cyclone developed along the coast of southern Brazil. The erroneous representation of the upper-level structure prevented the decrease of vertical wind shear which is an important factor to the development of a low-level warm core. In terms of precipitation, all the convective schemes show the increased precipitation during the initial stages of the cyclone, followed by a rapid decrease. These findings would be helpful in choosing the more appropriate cumulus parameterization schemes for cyclone simulations over South America, and in improving model predictions given the existence of model bias derived by imperfections in physical parameterizations.

Tornadoes in Ananindeua, Pará: Visual characteristics and atmospheric environments

2024-07-08T15:42:35-03:00

Tornadoes are intense atmospheric vortices produced by convective storms, capable of producing significant socio-economic damage. In Brazil, such phenomena occur more commonly south of 20°S, especially in the southern states; however, tornadoes occasionally occur north of this latitude. In the last two decades, the number of studies addressing these phenomena in Brazil, especially in the south and southeast regions of the country, has gradually increased, partially due to the greater public and scientific perception of the risk posed by tornado events in view of an increase in the number of tornadoes reports in Brazil, a likely consequence of the greater ease in reporting tornadoes with cell phone cameras and social media. Despite this, the number of studies addressing tornado events north of 20°S is still small and several aspects of these events are still unknown. This study documents the occurrence of tornadoes in the city of Ananindeua, located in metropolitan region of Belém, in the state of Pará, in northern Brazil. Several tornadoes have been reported in the city in recent years and there are indications of occurrence of tornadoes in the same region in recent decades. Some of these tornadoes have visual characteristics that differ from the typical appearance of landspout tornadoes, which are more commonly recorded at low latitudes, and resemble tornadoes associated with supercell thunderstorms. Ananindeua is located near several bodies of water, which can hypothetically influence the formation of tornadoes in the region through the production of vorticity close to baroclinic regions or convergence zones, both processes due to breeze systems. The main objective of this work is to document and analyze the visual characteristics and the atmospheric environment of several tornado events in Ananindeua. Based on this analysis, we seek to preliminarily identify mechanisms that affect the formation of tornadoes in the Ananindeua region and to improve the prediction of these phenomena.

Wavelet analysis applied to CO2 fluxes in native grasslands of the Pampa biome under the influence of different ENSO phenomena

2024-12-03T17:50:34-03:00

The Brazilian Pampa biome is recognized for its extensive area dedicated to livestock farming, being one of the main producers of beef in the country. Greenhouse gas emissions or absorptions, such as CO2, are influenced by periods associated with ENSO phenomena (El Niño, EL and La Niña, LN). Continuous and Cross Wavelet transform analyses are effective methods for investigating differences in the gas exchanges, allowing the examination of temporal CO2 variability and the relationship with meteorological variables at different time scales. The meteorological and CO2 flux data used in this analysis were collected from a flux tower at the Santa Maria experimental site, with CO2 fluxes obtained using the Eddy Covariance technique. Wavelet analyses demonstrated the ability to identify flux patterns across different temporal scales, considering the influence of distinct phases of the ENSO in the Brazilian Pampa biome. The results indicate that the main differences between the EL and LN phenomena occur on a time scale between 16 to 32 days in the relationship of CO2 flux and Precipitation, being in spring for EL and summer/autumn in LN. The observed temporal patterns of CO2 fluxes and environmental variables highlight the importance of modeling CO2 flux concerning meteorological trends.