## Results
### Aden  
The tide gauge record of Aden was analyzed in [21]. Figure 4 presents the RLR (revised local reference) and MET (metric) data of PSMSL (data downloaded from www.psmsl.org/data/obtaining/rlr monthly.data/44.rlrdata, www.psmsl.org/data/obtaining/met.monthly.data/44.metdata, accessed on 18 May 2018), plus their difference Delta RLR-Met. As the database is unstable (see Figure 3), the date of download is important. The different segments were found from either a change of the Delta RLR-Met, significant gaps without measurements, or specific mention in the station documentation from PSMSL. The station documentation from PSMSL is insufficient. It does not report changes in tide gauges. It is written:  
* 1937-1956 values based on high and low water readings;
* Aden 485/001 RLR (1962) is 9.1 m below BM PEO;
* 2007/8 one-minute sea level data downloaded from the IOC Sea Level Station Monitoring Facility Ostend. This is then converted to 15 min data for processing. 2008 monthly and annual mean sea  
Figure 4: PSMSL RLR (revised local reference) and MET (metric) data for Aden, plus their difference Delta RLR-Met. There were five segments, with four offsets to verify. level values have now been 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;
* The historic data for Aden (1879-1933) have been reviewed. As a result, the RLR factor for all that period has been set to 5.141 m;
* MSL = 16 mm has been applied to the RLR data for the period 1937-1956 using harmonic constituents from the GESLA2 (high-frequency tide gauge) dataset. The data for Aden showed five (5) sets of measurements, 1879 to 1893, 1916 to 1933, 1937 to 1956, 1957 to 1969 and 2007 to present. After having found the different segments, their alignment was then checked. A known pattern across the segment must be assumed. The simplest pattern is linear. As the length of the segments is usually short, polynomials do not work better. In the case of two segments of equal length, a breakpoint is placed at the center of the gap between two segments, while in the case of two segments of unequal length, the breakpoint is placed closer to the shortest segment. An offset in between the two segments is computed with the same values at the breakpoint from the left and right extrapolations. Figure 5a,b presents the latest Aden results, data from March 1879 to October 2013. Figure 5a shows the linear fittings applied to the five segments. Figure 5b shows the MSL aligned compared to the PSMSL RLR data. In none of the five segments, was there a rate of rise approaching the rate of rise of the segmented record proposed by PSMSL. In the PSMSL RLR data, the sea levels were rising at a rate of +1.28 mm/yr. In none of the segments were the sea levels are rising at such a rate. The mean trend through all segments (Figure 5a) supplied an elusive rate not anchored in observational records. We may even say that such a record must be discarded as improper. The rates were +0.53 mm/yr in segment 1, -0.78 mm/yr in segment 2, +0.49 mm/yr in segment 3, +0.28 mm/yr in segment 4, and finally -3.02 mm/yr in segment 5. This one is by far too short. 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 10.7 mm versus segment 1. Segment 3 was shifted down 42.6 mm versus segment 2. Segment 4 was shifted down 49.2 mm versus segment 3. Segment 5 was shifted down 50.3 mm versus segment 4. The slope was thus reduced from +1.28 to +0.02 mm/yr. The acceleration was also reduced from +0.0164 to +0.0038 mm/yr\({}^{2}\). Figure 5: Cont. Comparable results were obtained by [21], however no correction was introduced for the data of 1879 to 1893 and 1916 to 1933, which were aligned on their own in the metric version.