MRI data Model Average High Wave Data Maximum High Wave Data Average between Maximum and Minimum Tides Subsidence level estimation

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3.5 Sea Level Projection Component

3.5.1 MRI data Model

In order to obtain the sea level rise, the available model data in certain year was reduced by data in 1900, which were used as the baseline year when the first measurement of tidal gauge. Appendix shows that the value of sea level rise in 2010 2010 MSLM is about 0.292 m, in 2030 2030 MSLM is 0.287 m and in 2100 2100 MSLM is 0.406 m.

3.5.2 Average High Wave Data

High wave data were obtained from University of Hawaii Sea Level Center UHSLC, the complete data can be seen in Appendix 7. Calculation for defining inundation, the average value of high wave data has been multiplied by 30 due to hit to the material which stand on the coastline area. HW = 1.05430 = 0.316 m.

3.5.3 Maximum High Wave Data

The maximum of high wave data was obtained from the highest or maximum value of high wave data and also multiplied by 30 due to hit to the material which stands on the coastline area. HWex = 2.3830 = 0.715 m.

3.5.4 Average between Maximum and Minimum Tides

The tide pattern was stated see chapter 2.7.1 where there has a maximum and a minimum value from average data in any day. To predict the sea level, the distance value between maximum and minimum value has been measured. The tide data in this research were derived from WX Tide Software. TWL = 2.6 - - 0.2 = 1.4 m. 32

3.5.5 Subsidence level estimation

Subsidence’s in Surabaya is predicted and caused by the pressure of the heavy material such as building and heavy vehicles especially in Northern Surabaya which filled up by warehouse and freight transportation. Subsidence level data have been obtained from Badan Geology with 2003 – 2004 data observation. For this research these subsidence level data used as reference to predict land subsidence year by year. Subsidence value t SL is defined as the average of subsidence level data in a year with an assumption that the value of subsidence level is similar to 2003-2004. The average of subsidence level data SL can be calculated as follows, 1 t t = ∆ year projected t − year of available data, and the subsidence level formulated as follow: SL t SL t ∆ = 6 So that the value subsidence level in 2010, 2030 and 2100 is: 21 . 2004 2010 2010 − = SL = 0.12 m 21 . 2004 2030 2030 − = SL = 0.54 m. 21 . 2004 2100 2100 − = SL = 2.01 m.

3.5.6 High wave in El Nino and La Nina