## Results
### Mumbai  
The tide gauge of Mumbai was analyzed in [2] and discussed with respect to independent coastal morphological criteria [27]. Figure 8 presents the RLR (revised local reference) and MET (metric) data of PSMSL for Mumbai (data downloaded from www.psmsl.org/data/obtaining/rlr.monthly.data/43.rlrdata, www.psmsl.org/data/obtaining/met.monthly.data/43.metdata, accessed on 18 May 2018), plus their difference Delta RLR-Met. The different segments are clearly shown from either change in the Delta RLR-Met or significant gaps without measurements. The station documentation from PSMSL is insufficient. It does not report changes in tide gauges. It is written that:  
* Anomalously large value June 1946 and low values at end of 1946 (just before a data gap)--correct as received from authority;
* Data for 1916-1920 are MSL and were obtained from the Survey of India, Dehra Dun;
* Data for 1937-1948 are MTL (Mean Tide Level) and were also obtained from the Survey of India;
* Data from 1957 onwards are MSL;
* Data from 1957-1965 were obtained from the Pakistan Meteorological Department, while 1966-1985 from National Institute of Oceanography. Data from 1986-1987 were obtained from the University of Hawaii Sea Level Center using data supplied by the NIO (National Institute of Oceanography);
* Karachi 490/021 RLR (1947) is 9.7 m below BM 1 PP (circa 1920);
* New data from the Pakistan Navy for 1987 replace TOGA (Tropical Ocean and Global Atmosphere programme) data for Jan-Apr and Dec;  
Figure 8: PSMSL RLR and MET data for Mumbai, and their difference Delta RLR-Met. There were five segments, with four offsets to verify. The gauge at Karachi has been re-sited and is now no longer on Manora Island. The new gauge has been leveled into the old one. One-minute sea level data from 2007/2008 were downloaded from the IOC Sea Level Station Monitoring Facility Ostend. This was then converted to 15 min. data for processing. Monthly and annual mean sea level values from 2007/2008 were then extracted from the data. As the relationship for the prime benchmark remains the same there is no need to alter RLR. Details of the benchmarks have been derived from site installation information. Copies of these have been included in the port files and RLR file for reference;
* MSL = 10 mm was applied to the RLR data for the period 1937-1948. Values were derived using values from the GESLA2 (high-frequency tide gauge) dataset. A value of 10 mm was used from the historic databank of harmonic tidal constants gathered by the International Hydrographic Organization. The data for Mumbai showed five (5) sets of misaligned measurements, 1878 to 1930, 1931 to 1936, 1937 to 1958, 1959 to 1994, and 2007 to present. Figure 9a,b presents the latest Mumbai results, data January 1878 to October 2011. Figure 9a shows the linear fittings applied to the five segments. Figure 9b shows the MSL aligned compared to the PSMSL RLR data. When measured, the sea levels were decreasing, apart from the last segment. In the PSMSL RLR data, the sea levels were rising at a rate of +0.80 mm/yr (+0.77 mm/yr according to [24]. In two of the five segments, the sea levels were rising at about that rate, but in the remaining three segments, they were rising at a much smaller rate, or even decreasing. The rates were +0.15 mm/yr in segment 1, \(-\)6.73 mm/yr in the noticeably short segment 2, +0.98 mm/yr in segment 3, \(-\)0.16 mm/yr in segment 4, and finally +7.67 mm/yr in the short segment 5. The longest segments, segment 1 and segment 4, had very stable sea levels, +0.15 mm/yr and \(-\)0.16 mm/yr. Figure 9: Cont. The rising trend of the PSMSL RLR data is the result of the shifts of one segment versus the other, always upwards versus the values suggested by the alignment of the breakpoints. In the realignment, segment 2 was shifted down 38.8 mm versus segment 1. Segment 3 was shifted down 37.3 mm versus segment 2. Segment 4 was shifted up 6.5 mm versus segment 3. Segment 5 was shifted down 45.3 mm versus segment 4. The slope was thus reduced from +0.80 to -0.14 mm/yr.