The 5th International Symposium for Sustainable Humanosphere (ISSH) A Forum of Humanosphere Science School (HSS) Jakarta...
The 5th International Symposium for Sustainable Humanosphere (ISSH) A Forum of Humanosphere Science School (HSS) Jakarta, 29-30 September 2015
SATELLITE IMAGE ANALYSIS USING SATAID DURING EXTREME RAINFALL OCCURED IN SURABAYA ON DECEMBER 12th 2013 AND DECEMBER 2nd 2014 Richard Mahendra Putra* State College of Meteorology Climatology and Geophysic Jakarta, Indonesia *Corresponding author:
[email protected] Abstract Heavy rains occured in Surabaya on December 12th 2013 and December 2nd 2014. Both events are included in extreme weather category. This study is done to analyze the pattern of the clouds during the events. This study uses the analysis of top cloud temperature during heavy rain events. Analysis of satellite imagery MTSAT (Multifunctional Transport Satellites) from the IR1 channel is done by using SATAID software that shows convective cloud coverage over Surabaya area. Both of heavy rain cases occur in different time. On December 12th 2013, heavy rain occured during 05.00 to 12.00 UTC and December 2nd 2014 at 09.00 to 15.00 UTC. SATAID analysis shows heavy rain occured because of convective cloud cover over Surabaya. Keywords: Heavy Rain; MTSAT; Infrared; SATAID; Top Cloud Temperature Introduction Indonesia is located in the lower latitudes. Most of Indonesia is an ocean, so it will be a greater amount of evaporation and has a potential to occur extreme weather such as heavy rain. According to KBMKG Regulation No. Kep. 009 in 2010 about Standard Operating Procedure Implementation of Early Warning, Reporting and Dissemination extreme weather, heavy rain is the rain which have minimum intensity of 50 (fifty) millimeters (mm) / 24 (twenty four) hours or 20 (twenty) millimeters (mm) / hour. Both case of this studies, the intensity of rainfall that occurred more than 100 mm in 24 hours. On December 12th 2013 rainfall observed is 129.3mm and December 2nd 2014 the intensity of rainfall is 102.5 mm (BMKG, 2010). This study is to determine the characteristics of cloud brightness observed in MTSAT satellite using SATAID software and determine the pattern of clouds during heavy rain events. MTSAT satellite has a fixed orbit in 140˚E exactly located in Biak. It has height +36000 km from the earth's surface. MTSAT Satellite has two sensors, i.e Infrared (IR) and Visible (VIS). Infrared sensors have four channels, they are IR1, IR2, IR3, and IR4. IR1 channel is used to observe clouds, the movement of the clouds, the movement of winds and storms. IR2 is used to observe sea surface temperature, as well as monitoring the volcanic. IR3 is called Water Vapor channel is used for monitoring the movement of water vapor in the atmosphere. IR4 is called Near Infrared is used to monitor the heat source and cloud at night (BMKG,2009). Visible sensors are used to detect the areas of the cloud at a location to determine the value of an object's albedo. As a result, these sensors can only be used during the daytime. Materials and Methods This study was taken from case of heavy rain events on December 12th 2013 and December 2nd 2014 in Surabaya. Surabaya is located in 7º16’ S - 7,267ºS and 112º43’ E - 112,717ºE.
Figure 1. Location Map of Surabaya in A symbol
The data used in this case are: 1. MTSAT satellite data in z file form of December 12th 2013 and December 2nd 2014. Those data are processed by using SATAID software to display enhanced cloud top temperature, the time-series, and contour map. These data are obtained by using IR1 channel. 2. Weather data from Meteorogical Station of Perak I Surabaya. Meteorogical parameters are air temperature, relative humidity, air pressure and rainfall observed from the station are used to validate the events and the satellite imageries. The method used in this case is an analysis of clouds condition during heavy rain events in Surabaya. Analysis is from observation time series of top cloud temperature for 24 hours during the day, then compare the two events of heavy rain. Besides analyze the temperature of the top cloud, author also analyze the contour of cloud when heavy rain occured. Then validation using analysis of weather observation of Meteorological Station Perak I Surabaya. Results and Discussion Heavy Rainfall December, 12th 2013
Based on figure 2, temperature has significantly decreased at 05.00 UTC to 06.00 UTC by -3.6˚C. This temperature decreasement in an hour shows the occurrence of heavy rains over that area. Then, the air temperature continued to decrease until 08.00 UTC and then became constant. Based on relative humidity data (figure 3), the humidity significantly increased at 06.00 UTC by 16% in an hour. The increasement continued until reaching maximum value of 97% at 12.00 UTC. This humidity increasement was caused by greater content of water vapor around the area due to rain. Based on figure 4, the air pressure has increased until 03.00 UTC and decreased until reaching the lowest value, 1007 mb at 08.00 UTC. The pressure decreases at 09.00 UTC until reaching maximum value, 1008.9 mb at 14.00 UTC. The decreasment of pressure indicates the cloud development process due to local convectivity. Based on rainfall measurements in Meteorological Station of Perak I Surabaya (figure 5), the rain started to occur at 06.00 UTC until 12.00 UTC. The measurement of rainfall at 06.00 UTC obtained 46 mm, at 09.00 UTC obtained 78mm and 12.00 UTC obtained 5mm.
Figure 2. Temperature Every Hour
Figure 3. Relatif Humidity Every Hour
The 5th International Symposium for Sustainable Humanosphere (ISSH) A Forum of Humanosphere Science School (HSS) Jakarta, 29-30 September 2015
Figure 4. Air Pressure Every Hour
Figure 5. Rain Intensity Every 3 Hour
Satelite Analysis at December 12th 2013 Based on analysis of satellite imagery data using SATAID (figure 6), Surabaya area was covered by convective clouds from 05.00 UTC. This is proved by the satellite image of blue and red color. Blue color shows cumulus and red shows cumulonimbus. Then convective clouds spread to cover the all area of Surabaya at 07.00 to 12.00 UTC. The coverage triggered a heavy rain accompanied by lightning and strong winds.
Figure 6. Satellite Imagery using SATAID
According to figure 7, significant decreasement of top cloud temperature started to occur from The 5th International Symposium for Sustainable Humanosphere (ISSH) A Forum of Humanosphere Science School (HSS) Jakarta, 29-30 September 2015
05.00 to 09.00 UTC which reached -60˚C. That condition indicates that convective cloud type was formed, especially cumulonimbus. Convective clouds have the potential to cause heavy rain accompanied by lightning and strong winds. Based on top cloud contour at 08.00 UTC, there was cloud coverage with cold top over Surabaya area with top cloud temperature between -50˚C to -75˚C. It was the trigger of heavy rains on that time.
Figure 7. Time Series of Top Cloud Temperature (left) and Contour of Top Cloud Temperature (right)
Heavy Rain at December,2nd 2014 Based on data of temperature (Figure 1), the air temperature decreased significantly until -8.5˚C during 09-12 UTC. Significant decline in temperature indicates the occurrence of heavy rain. Based on data of Relatife Humidity (Figure 2), the value of humidity have significant increasing during 09-13 UTC by 35%. This increase indicates heavy rain events is happening. Based on data of air pressure (Figure 3), the air pressure decreased significantly during 01-09 UTC by -3.4 mb. This decrease indicates a strong local convective processes happend in Surabaya. As a result it will make of convective clouds that may produce heavy rainfall accompanied by lightning and strong winds. Based on rainfall measurements at the Meteorological Station of Perak I Surabaya (figure 4), rain occurred since 00 UTC, but the measure at 03, 06 and 09 UTC rain measurement results is TTU (unmeasured). Later measurements at 12.00 UTC shows the extreme value is 94.3 mm. Rain continued and measurement at 15 hours UTC showed a value of 8.2 mm
Figure 8. Temperature Every Hour
Figure 9. Relative Humidity Every Hour
The 5th International Symposium for Sustainable Humanosphere (ISSH) A Forum of Humanosphere Science School (HSS) Jakarta, 29-30 September 2015
Figure 10. Air Pressure Every Hour
Figure 11. Rain Intensity Every 3 Hours
Satelite Analysis at December 2nd 2014 Based on analysis of satellite imagery data MTSAT (Multifunctional Transport Satellite) IR1 channel, statiform cloud around Surabaya shown since 06.00 UTC by grayish-white color. An then at 08.00 UTC convective cloud has been formed which characterized by the blue color that indicates for cumulus and red color for cumulonimbus. Convective clouds continue be around Surabaya until 15 UTC.
The 5th International Symposium for Sustainable Humanosphere (ISSH) A Forum of Humanosphere Science School (HSS) Jakarta, 29-30 September 2015
Figure 12. Satellite Imagery using SATAID
Based on the figure 13 significant decreasing of temperature occur from 08.00 UTC until 12.00 UTC which reached -54˚C. Types of clouds formed at that time was convective clouds, i.e cumulus and cumulonimbus and both of them have the potential to cause heavy rain accompanied by lightning and strong winds. Based on top cloud contour at 12 UTC shows that there is a cold cloud that cover area around Surabaya, with top cloud temperatures between -25˚C to -70˚C. It shows that there is a convective clouds that covering the area of Surabaya (Sagita, 2013).
Figure 13. Time series of temperature in top cloud (left) and Contour cloud pattern when heavy rainfall was occuring (right)
Conclusion On December 12th 2013, heavy rain occured at 05.00 – 12.00 UTC. This is evidenced by significant increasing of Relatife Humanity during 05.00-06.00 UTC by 16% and observation of rainfall at 06.00 UTC. The increase of humadity is continues until it’s reaches a maximum value of 97% at 12 UTC. The contour of top cloud temperature shows that there is a cold cloud cover in Surabaya with top cloud temperatures between -50˚C to -75˚C. It can be possible to occur heavy rainfall. Based on weather observations in Meteorological Station of Perak I Surabaya on December 2nd 2014, the growth of convective clouds begin since the early morning. This is evidenced by the air pressure dropped significantly at 01.00-09.00 UTC by -3.4 mb. Then heavy rain occurred at 09.00-13.00 UTC. This is evidenced by the significant increasing the value of RH at 09.00- 13.00 UTC by 35%. In addition, a significant decreasing temperature also occured at 08-12 UTC by -8.4˚C. The cloud contour temperature shows that there is a cold cloud cover in the area around Surabaya with top cloud temperatures between -25˚C to -70˚C. It shows that there is a convective clouds that covering the area of Surabaya.
The 5th International Symposium for Sustainable Humanosphere (ISSH) A Forum of Humanosphere Science School (HSS) Jakarta, 29-30 September 2015
Acknowledgment The author would like to say thank you for those who have helped in completing this paper. Authors hope with this paper, we can understand the weather phenomena more easily. There are many flaws in this paper, to the criticisms and suggestions can be delivered to my email References BMKG. 2009. Diklat Teknis Meteorologi Publik (Pusat Pendidikan dan Pelatihan Meteorologi, Klimatologi, dan Geofisika. Jakarta BMKG. 2010. Prosedur Standart Operasional Pelaksanaan Peringatan Dini, Pelaporan, dan Diseminasi Informasi Cuaca Ekstrem. Jakarta Harsa H, dkk. “Pemanfaatan SATAID Untuk Analisa Banjir dan Angin Puting Beliung : Studi Kasus Jakarta dan Yogyakarta”. In Jurnal Meteorologi. Jakarta: BMKG Findy, R dan Syaifullah M D. 2011. “Kajian Meteorologi Bencana Banjir Bandang di Wasior, Papua Barat. In Jurnal Meteorologi and Geophysic. Jakarta: BMKG SATAID data. 2013. ftp://202.90.199.115/, access August 10th 2014 Sagita, N. 2013.”Satellite Image Analysis of MTSAT and TRMM Using Software ER Mapper, SATAID and Panoply When Extreme Rainfall occur in Manado Area On Februari 16th 2013”.
The 5th International Symposium for Sustainable Humanosphere (ISSH) A Forum of Humanosphere Science School (HSS) Jakarta, 29-30 September 2015
