20CRv3 psobs_posterior key

Description of each field in the psobs_posterior.txt file for 20CRv3

 

Fields separated by single space

 

Field 1, len. 19 (pos.1-19)

        Datetime & Observation ID

        YYYYMMDDHH+{9 digit ISPD unique ID suffix}

 

Field 2, len. 30 (pos.21:50)

        Station name

        From source record or station library table

 

Field 3, len. 12 (pos 53-64)

        Station ID

        Represents marine call sign or other identifier when present

 

Field 4, len. 2 (pos 67-68)

        Observation type

        ps = pressure

 

Field 5, len. 3 (pos 70-72)

        NCEP observation type

        Missing: 999

        180 Marine Observation Data

        181 Station Observation Data

        183 Station Observation only reporting sea level pressure

        193 Digitized mean sea level pressure bogus

        194 Old Weather

        195 Weather Detective

        3x0 Synoptic (0,6,12,18UTC) Central Pressure from a tropical cyclone best track dataset

        3x1-3x5 Synoptic (0,6,12,18UTC) Central Pressure for a category 1-5 tropical cyclone from a tropical cyclone best track dataset

        4x0 Non-synoptic Central Pressure from a tropical cyclone best track dataset

        5x0 Bogus Central pressure for a tropical depression derived from tropical cyclone best track wind dataset.

        5x1-585 Bogus Central Pressure for a category 1-5 tropical cyclone derived from a tropical cyclone best track wind dataset.

        Second digits of the NCEP observation type code for tropical cyclones are designated for the regional codes based on the basin/sub-basins classifications by National Climatic Data Center Global Tropical Cyclone Stewardship.

                1. Eastern North Pacific (sub-basin: Central Pacific)

                2. Eastern North Pacific

                3. North Atlantic

                4. North Indian

                5. South Indian

                6. South Pacific (sub-basin: Eastern Australia)

                7. South Pacific

                8. West Pacific

 

Field 6, len. 6 (pos 75:80)

        Longitude, in deg. E

        Min: 0.00, Max: 359.99

 

Field 7, len. 6 (pos 82-87)

        Latitude, in deg. N

        Min: -90.00, Max: 90.00

 

Field 8, len. 7 (pos 89-95)

        Observed station pressure or sea level pressure

 

Field 9, len. 5 (pos 98-102)

        Time offset of observation time from analysis time

 

Field 10, len. 7 (pos 104-110)

        Observed station pressure or sea level pressure (same as field 8)

 

Field 11, len. 1 (pos 112)

        Skipped flag

        1 – observation was skipped, 0 – observation was assimilated

 

Field 12, len. 10 (pos 114-123)  

        Observation bias  

        For station data, this is the difference between the observation and first guess averaged over the past sixty days. (Approx.) zero for marine observations. The 1851-1870 ship bias correction is not included in this field. (Bias is subtracted from observation for bias-corrected value.)

 

Field 13, len. 10 (pos 125-134)

        Obfit_prior

        Observation minus first guess

 

Field 14, len. 10 (pos 136-145)

        Obfit_post

        Observation minus analysis

 

Field 15, len. 10 (pos 147-156)

        Obsprd_prior

        Variance of first guess ensemble interpolated to observation time and location

 

Field 16, len. 10 (pos 158-167)

        Obsprd_post

        Variance analysis ensemble interpolated to observation time and location

 

Field 17, len. 7 (pos 169-175)

        Oberrvar_orig_out

        Original observation error variance

 

Field 18, len. 7 (pos 177-183)

        Oberrvar_out

        Observation error variance if modified by analysis

 

Field 19, len. 7 (pos 185-191)

        Oberrvaruse

        Observation error variance used in analysis (incl. nonlinear QC modification) Note values of 99.9999 are the “new QC”: instead of discarding the obs, we just set the observation error to be very large.

 

Field 20, len. 8 (pos 193-200)

        Paoverpb_save

        H(Pa)H^T/H(Pb)H^T; analysis ensemble covariance at the space-time location of the observation, divided by forecast ensemble covariance at the space-time location of the observation.  Used in calculation of localization length scale.

 

Field 21, len 4 (pos 202-205)

        Prob. of a gross error

 

Field 22, len 7 (pos 207-213)

        Localization length scale (in km)

 

Field 23, len 7 (pos 215-221)

        Localization length in thousands of km

 

Field 24, len 1 (pos 223)

        QC failure flag

        0 if passed quality control check, 1 if failed