1. University of São Paulo – Brazil
9 years of lightning measurements in South America as detected by STARNET
Carlos A. Morales
University of São Paulo – Brazil

2. Background
STARNET is a long range lightning detection network that uses Very Low Frequency (VLF) receivers to measure the radio noise (Ez) emitted by lightning discharges in the frequency range of 7-15 kHz.
STARNET was developed by RDI under a NASA/SBIR Program coordinated by Dr. J. Weinman, , and uses the ATD technique to locate sferics (Lee ,1986).
In 2001 the National Observatory of Athens (NOA) deployed 6 antennas through the European continent (Athens, Napoli, Lisbon, Hampshire, Iasi, Roskilde) and created the ZEUS network.

3. Background
The South American STARNET was initially deployed in 2006 with 3 antennas (Guadeloupe, Fortaleza and São Paulo),(NSF and COELCE) integrated with African receivers (Nigeria, Ethiopia, Tanzania, and South Africa) of World-ZEUS (NSF and AMMA project).
During , 4 antennas were installed in Brazil (Campo Grande, São Martinho da Serra, Brasilia and Manaus) (CNPq – SIPAM/FINEP). Along 2012, 4 more antennas were installed at Belém and Ilhéus (Brazil), Cape Verde and Trellew (Argentina) (SIPAM, COELCE, USP). August 2015, 1 more antenna at La Serena, Chile (FAPESP)
2014 – USP is able to maintain and manufacture the VLF antennas.

4. Background .
The present VLF receivers are capable to measure up to 100 sferics per second through continuous Ez measurements.
Each receiver records Ez waveforms and stores on 16 second files.
Every 1 minute, the collected waveforms are transmitted to the central computer station at USP.
Lightning locations are evaluated every 5 minutes, if communication issues are solved it is possible to do every 1 minute.
The locating algorithm can handle 30 different 9 sensors configurations to compute the sferics positions and polarity (Morales et al., 2007), but it requires a minimum of 4 receivers to locate a sferics.
After one month, we perform the reprocessing to use receiver data that was not available in realtime.

5. Locations of STARNET VLF antennas
Since 2015, STARNET has 12 operational VLF antennas and 1 backup at University of São Paulo
Sensors used
In the locating
Algorithm

6. Location Accuracy WWLLN - 2009 12.1 km GLD360 (2012-2013)
RINDAT
(2009)
LIS All Domain (2009)
LIS Brazil (2009)
WWLLN (2009)
Mean Difference(km)
8.43
22.08
19.23
12.1
# of Matches
306,875
22,956
6,538
6,260,990
GLD360
( )
Difference (km)
Matches
01S-09N
27-17W
(I) 26.66
87,597
08S-02N
65-55W
(A) 11.13
728,870
15S-05S
53-43W
(T) 7.58
1,345,711
21S-11S
70-60W
(B) 12.15
1,752,731
WWLLN I A T B
12.1 km
Morales et al., 2014 – ILDC

7. Over South America :12/2014 – 03/2015
GLD360
4RX
5RX
6RX
7RX
1,405,084
1,962,486
1,265,826
1,223,040
17,0 km
11,2 km
8,4 km
7,5 km
RXs 4 5 6 7
RXs 4 5 6 7
Over South America :12/2014 – 03/2015

8. Detection efficiency
R=S
2X=60%
1X=40%
Morales et al., 2014 – ILDC

9. Local
UTC
Dec/2013-Mar/2014

10. 62 – 52 W & S
Night
Night
Day
Dec/2013-Mar/2014

11. Sferics Measurements over South America

12. 2009
2006
7 rx
7 rx
2012
8 rx
2007
4 rx
2010
7 rx
2013
12 rx
2014
2008
5 rx
2011
7 rx
12 rx

13. Year
Sferics Measured
2006
7,585,405
2007
3,290,597
2008
17,204,274
2009
123,394,328
2010
45,015,908
2011
36,768,128
2012
62,397,672
2013
180,928,944
2014
133,497,008
2015
227,717,248

14. Monthly Sferi cs Distribution 2014-2015

15. Sferics Accumulation - 2015
# of Sferics

16. Annual Sferics Rate

17. 2014
2015
Sferics/km2/year

18. Number of days with lightning

19. 2015

20. SFERICS
RANKING IN BRAZIL

21. Ranking

22. Ranking
11 STATES = 82%
AM, PA and MT = 40-50%

23. Ranking in South America

24. Number of Sferics per Country

25. Sferic Rate per Country

26. Diurnal Cycle

31. STARNET web interface http://www.starnet.iag.usp.br FTP area
Realtime data
Re-processed data
Google interface
Thunderstorm Alerts
Rainfall Estimation – SIRT
FTP area

32. THANKS carlos.morales@iag.usp.br And Visit: