National Institute for Space Research (INPE) will work on a technical report to give to the “Operador Nacional do Sistema” (ONS) which analyses the atmospheric conditions in Brazil in the night the blackout occurred. For that, the technicians from the Atmospheric Electricity Group (ELAT) and the Weather Forecast and Climate Studies Center (CPTEC) both from INPE, have been working on this project together as atmospheric discharge (thunderbolts) and some other meteorological issues, as wind force and rains.
Up to the moment, it is possible to state that squall lines were the cause of heavy rains, thunderbolts and winds happened in Paraná and São Paulo locations. As you can see in the images below checked by CPTEC/INPE meteorologist experts.
Unstable mass of hot air that was over the southern area, SP and MS further a cold front just arrived from the south, on Tuesday, were the causative factors that lead to squall lines and thunderstorms.
Figure 1: November 10th, 2009 -Thunderbolts recorded between 21:55 and 22:55. Source: Rede Integrada Nacional de Detecção de Descargas Atmosféricas (RINDAT)
Figure 2: At 22:15 a radar image shows two areas with heavier rains (orange color), one of them around Jaú and the other one in Itaberá region, both cities from São Paulo interior.
Figure 2: At 22h15min - São Roque’s Metereological Radar Image (SP), operated by “Departamento de Controle do Espaço Aéreo (DECEA). The colors point the intensity of the reflectivity that can be related with the rain intensity. Source: DECEA
Figure 3 is a satellite image in infrared channel that shows the temperature from the top of the clouds at 22:15 between southern and southeastern part of Brazil. One can see significantly low temperature values, between – 70C and -80C, in three regions of São Paulo state. The lower the temperatures are on the top of the clouds, more profound and heavier they are.
Figure 3: Figure 3 is a satellite image in infrared channel that shows the temperature (in Celsius) from the top of the clouds at 22:15, as shows the legend below. Source: CPETEC/INPE
The upper image assessment was performed by the Weather Forecast and Climate Studies Center specialists from National Institute for Space Research (CPTEC/INPE).
Thunderbolts
According to Atmospheric Electricity Group specialists (ELAT) from INPE, although a thunderstorm was happening close to Itaberá, with thunderbolts by the time the Blackout occurred, the closest electrical discharge from the electrical system were about 30 km from the substation and about 10 km away from one of the four lines of Furnas of 750kV and 2 km from two other lines of 600 kV, that come out from Itaipu heading to São Paulo.
For ELAT/INPE specialists, the low intensity electrical discharge recorded (lower than 20 kA) would not be able to cause a line disconnection, even if it struck over it, according to Rede Brasileira de Detecção de Descargas (BrasilDat) information, that when the blackout occurred the line was operating with a good performance. Generally only discharge with intensity superior to 100 kA, when striking a line directly could cause transmission line disconnections when operating with tension as high as Itaipu lines (two of 600kV and two of 750kV).
