Summary of corrections to the HOT database.
-------------------------------------------

The following is a chronological summary of the main corrections applied 
to the HOT data. Details about corrections and modifications to the HOT 
dataset can be found in ../Current.status

Date correction applied            Description

17 November 2003 CTD and bottle salinity corrections. Corrections to improve 
                the quality of the database salinities. See 
                salinity_corrections.txt for details. 

26 August 2003  Corrected sea surface bucket temperature 
                from cruises HOT-128 through 132 (July-November 2001).
	        Temperatures were high by about 0.5 degC as compared to surface
	        CTD data. See met_corr2.txt for details. 

2 May 2002      Additional corrections to meteorological data. See 
                met_corr020502.txt for details. 
	        
16 Aug. 2001    Some of the meteorological observations from cruises 1 through 
                110 have been corrected. See details in met_corr.txt.
 
22 Jan. 1999    A correction was applied to the CTD temperatures and salinities
                from cruises before 1996. This correction was due to an 
                unaccounted for pressure effect on the temperature sensors, and 
                also due to the viscous heating of the temperature sensor tip 
                due to the water flow around it. Details on the nature of these
                corrections and their effect on the CTD data can be found in 
                visc_pres_cor.txt.

15 Dec. 1995    Nutrients with zero (0) value were being entered as invalid 
                data for cruises 44 through 50. A list of the corrected data 
                is provided in zero_nuts.txt.

24 Mar. 1994    Bottle salinities from years 2, 3 and 4 were re-flagged using 
                a CTD-bottle difference criteria that is less strict for 
                bottles in the pycnocline. The new method is documented in
                flagsal.txt, together with a list of the bottles affected.

                Erroneous down-cast CTD oxygen values were corrected for some 
                of the cruises during years 2, 3 and 4. See updmatch.txt for 
                details on the magnitude of the correction and files affected.
                
                Some of the bottle data from 1990-1991 HOT cruises were
                corrected after the WHPO quality evaluation. See quality2_3.txt
                for details.