QUALITY ASSESSMENT OF SEA LEVEL DATA                
                                           by the                               
                   UH SEA LEVEL CENTER/NATIONAL OCEANOGRAPHIC DATA CENTER     
                                 JOINT ARCHIVE FOR SEA LEVEL                    
                                                                                
              Station  : Keppel Harbour            Latitude:  01 15.8N          
              Country  : Singapore                Longitude: 103 49.3E          
              JASL #   : 327A                 Time Meridian: 120E (GMT + 8 hr)  
              GLOSS #  : 044      TOGA #: none       NODC #: 10101304           
              Contributor  : Port of Singapore Authority                        
                             PSA Building                                       
                             460 Alexandra Road                                 
                             Singapore 0511                                     
              Originator   : same                                               
              Original Data: analog                                             
              Instrmnt Type: A.OTT Float Type                                   
              Digitzd Intvl: 1 hour                                             
              Present Data : Hourly, daily, and monthly values obtained by:     
                    Hourly : digitized from chart paper                         
                    Daily  : 119-point convolution filter (Bloomfield, 1976)    
                             centered on noon applied to the hourly data        
                             with respective periods of the 95, 50, and 5%      
                             amplitude points at 124.0, 60.2, and 40.2 hours    
                    Monthly: Simple average of all daily values; calculated if  
                             7 or fewer days are missing                        
              Span of data : 13 Aug 1981 - 31 Jan 1990
              Gaps > 1 mon : none                                               
              Time Refernce: GMT (hours 00-23)   Space-filler Flag   :-9999     
              Units        : millimeters         Missing Data Flag   : 9999     
              Existing     : Yes                 Operational         : Yes      
              Sat. Trans.  : No                  Distribution        : 1981-1990
              Refernce Levl: The sea level heights are referred to the chart    
                             datum which is also the zero level of the tide     
                             gauge. Bench mark information is available upon    
                             request from the contributors.                     
              Comment      : The residual series are very noisy, which is       
                             probably due to shallow water tides that are not   
                             resolved by the harmonic analysis or due to timing 
                             drifts of less than 15 minutes.  The timing is
                             clearly bad in 1981.   The differences in daily
                             values with Tanjong Pagar and Johor Bahru suggest
                             subtle level shifts which can not be distinguished
                             by analyzing the hourly residuals.  It is not
                             clear which series has the shifts.  The Keppel
                             Harbor site clearly has an upward trend associated
                             with settling of the harbor foundation.
                                                                                
                    CI MISSING              REPLACED GAPS     QUESTIONABLE      
              YEAR (%) DATA                 OR BAD DATA       FLUCTUATIONS      
              ---- --- -------------------- --------------- --------------------
              1981  38 283-286              none            see comment above
              1982 100 none                 (11)118-(22)118 "       "     "
              1983  96 350-365              none            "       "     "     
              1984 100 none                 none            "       "     "     
              1985 100 none                 none            "       "     "     
              1986 100 none                 none            "       "     "     
              1987 100 none                 (16)265-(15)266 "       "     "     
              1988  94 89-93,291-299,       none            "       "     "     
                       328-336                                             
              1989  99 357-362              none            "       "     "
              1990   9 none                 none            "       "     "