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Statistics on global surface marine meteorological and oceanographic data are compiled monthly by personnel of NOAA's
NWS/NCEP/Central Operations. These data include those which are observed/measured by ships (including those vessels that are part of the
U.S. Voluntary Observing Ship Project), moored and drifting buoys, Coastal Marine Automated Network (CMAN) stations, and tide gauge stations
(tide gauge data are provided by NOAA's National Ocean Service/Center for Operational Oceanographic Products and Services (NOS/CO-OPS)).
Separate statistics are compiled monthly for specified vessels in the Gulf of Alaska and for specificed member vessels of the
International SeaKeepers Society. The data for which these statistics are compiled include sea-level pressure, air temperature, and wind direction
and speed (for the surface meteorological data), and sea surface temperature (for the oceanographic data).
Only 1 year's worth of statistics will be available at any given time on this web site. Please note that the monthly statistics are updated on
the first business day of each month. I.e. if the 1st falls on a weekend or on a Federal Government holiday, the statistics are updated on the first
business day which follows the weekend the or holiday.
The global monthly statistics are sent to the
UKMet Office in Bracknell, England each month (the UKMet Office has been designated by the
World Meteorological Organization (WMO) as the lead center for monitoring surface marine observations), where they are consolidated with
additional statistics and forwarded to platform managers. The platform managers may then investigate platforms listed in the statistics to see if
instrumentation needs to be corrected. Please note that the statistical files available via this web site are not indentical to those passed to
Bracknell, in that the ship/platform names are included in the files on this web site (they are not included in the Bracknell files).
The monthly statistics produced for the Gulf of Alaska vessels and for the International SeaKeepers Society vessels are made available to those
program managers via this web site, so that they may evaluate the performance of select vessels in their area of interest.
All of the monthly statistics are computed using differences between the observed data and first guess fields from one of 2 NWS numerical
models. This file explains the method of comparison between the data and first guess fields, and also provides the criteria used in determining
which platforms will be listed in the NCEP Central Operations (NCO) global marine statistics each month.
Standard of Comparison
Data from each platform (ships, moored (fixed) buoys, drifting buoys, CMAN platforms, and tide gauge stations) are compared to forecasts from
one of 2 NWS numerical models for each of 4 daily synoptic periods. Each synoptic period is a 6 hour window centered on the times given in the
table below. The first guess valid times are also given below. All data observed/measured during each synoptic period are compared to the first
guess valid for that synoptic period. The first guess is interpolated to the platform's location and differences between observation and first guess
are computed. Differences between observed data and forecasts are archived four times daily.
| Synoptic Period | Numerical Model Used | First Guess Valid Time |
|---|---|---|
| 0000 UTC | 6-hour forecast from the 1800 UTC run of NWS's Global Data Assimilation System (GDAS) | 0000 UTC |
| 0600 UTC | 6-hour forecast from the 0000 UTC run of GDAS | 0600 UTC |
| 1200 UTC | 6-hour forecast from the 0600 UTC run of GDAS | 1200 UTC |
| 1800 UTC | 6-hour forecast from the 1200 UTC run of GDAS | 1800 UTC |
If the GDAS is unavailable for a particular synoptic period, a 6-hour forecast from the previous run of NWS's
Global Forecast System (GFS) is
used instead.
Each synoptic period includes data with observation times +/- 3 hours as follows:
| Synoptic Period | Observation Times of Data |
|---|---|
| 0000 UTC | 2100 UTC (previous day) through 0259 UTC |
| 0600 UTC | 0300 UTC through 0859 UTC |
| 1200 UTC | 0900 UTC through 1459 UTC |
| 1800 UTC | 1500 UTC through 2059 UTC |
No time interpolation between observed data and first guess is done (i.e. an observation from 1000 UTC or 1400 UTC will be compared to a first
guess valid at 1200 UTC).
Criteria for specific parameters
For each of the 5 parameters (sea-level pressure, air temperature, wind speed, wind direction, and sea surface temperature) included
in the monthly statistics, the following criteria must be met in order for a particular platform to be listed in the NCO global monthly
statistics
Sea-level pressure (slp):
Air temperature:
Wind direction:
Wind speed:
Sea surface temperature (sst):
Specific callsigns were given to NCO to indicate those vessels which are to be included in these monthly statistics. No other criteria must
be met, except that the vessels must have at least one observation during the desired month. If a vessel reports only once during a
specific month, then the bias for any reported parameter is not a mean bias but is merely the difference between observed and first guess
values for that parameter. Standard deviation is only computed when a vessel has 2 or more reports for any particular parameter in the
month. As with the global monthly statistics, gross errors are not included in computations of bias or standard deviation (see Definition
of gross errors below).
With the exception of wind direction, the bias for each parameter is always computed as (observed data - first guess). A mean difference bias for
slp of -4.8 mb would mean that the observed slp for that platform is, on average, 4.8 mb lower than the first guess slp. Also, a low standard
deviation (SD) of the difference would mean that the platform's bias is consistent (the closer to 0 the SD is, the more consistent that platform is
for that parameter). For example, if the slp bias was -4.8 mb and standard deviation of the difference was 1.0, that would imply that the platform
consistently was around 4.8 mb too low with its slp. If the SD is high, then the platform has a lot of variability for the parameter in question, with
with regards to its comparison with the first guess.
Calculation of bias and standard deviation for wind direction
For platforms reporting wind direction that is consistently close to 180 degrees off the first guess wind direction, using the regular algorithm of
(observed wind direction - first guess wind direction) would result in a very large SD and bias, which would make it difficult to detect the wind
direction error. The ideal for this situation would be to have a small SD with a bias on the order of 180 degrees. This is possible with the use of
the algorithm used by Meteo-France's Centre for Marine Meteorology (Centre de Meteorologie Marine (CMM)) in computation of wind direction
statistics for moored and drifting buoys. This algorithm computes bias and SD for the following series:
where Obs = observed wind direction and FG = first guess wind direction.
The bias and SD are computed for each of the above 4 series. The smallest of the 4 SD values is selected and then (bias - i) (where i is 0, 90, -90,
and 180, respectively) is selected as the actual bias if the series ((Obs + i) - FG) was the series associated with the smallest SD. See the following
table for more details.
| If smallest SD is computed for | Bias used is |
|---|---|
| (Obs - FG) | bias = ((bias of (obs - FG)) - 0) |
| ((Obs + 90) - FG) | bias = ((bias of ((obs + 90) - FG)) - 90) |
| ((Obs - 90) - FG) | bias = ((bias of ((obs - 90) - FG)) - (-90)) |
| ((Obs + 180) - FG) | bias = ((bias of ((obs + 180) - FG)) - 180) |
Using this algorithm for all wind direction bias and SD computations will ensure that the most accurate representation of the difference between
observed wind direction and first guess wind direction will be used and displayed in the monthly statistics.
Sample lines from global monthly statistics (and explanation)
NCEP CENTRAL OPERATIONS (NCO) PLATFORM STATS
AUGUST 2024
SEA-LEVEL PRESSURE FOR ALL HOURS
PLATFORM SHIP/PLAT. NAME TYPE NO. REPORTS MEAN DIFF SD DIFF # GROSS ERR
3FFA5 MSC DIVINA SHP 50 11.9 2.1 3
The above lines were taken from the global monthly statistics produced for August 2024. The platform shown has the callsign 3FFA5. Its name
Caveat
Please note that a platform's appearance in the monthly statistics does not necessarily mean that the platform's data are bad. A high bias can be
indicative of a persistent problem with the first guess at the platform's lcoation. While the model's grid resolution and topogoraphical resolution are
1 degree x 1 degree, this is still not fine enough to depict small-scale local meteorological and oceanographic effects. In addition, the first guess, in
general, performs more poorly in the Southern Hemisphere than in the Northern Hemisphere, due to lower data counts (much less land south of
the Equator, so not nearly as many land-based surface and upper air observations, plus major shipping lanes are primarily in the Northern
Hemisphere).
An observation is considered to be a gross error if it differs from the first guess by the following values:
| slp | abs(obs - fcst) ≥ 15.0 mb |
| air temperature | abs(obs - fcst) ≥ 15.0 deg C |
| wind direction | abs(obs - fcst) ≥ 100 degrees |
| wind speed | abs(obs - fcst) ≥ 15.0 m/s |
| sst | abs(obs - fcst) ≥ 15.0 deg C |
| abs: | absolute value |
| obs: | observation |
| fcst: | forecast (first guess) |
By convention, gross errors are not used in the computation of the mean difference or standard deviation.
Platform types seen in monthly statistics
| Abbreviation | Type |
|---|---|
| SHP | ship |
| DB | drifting buoy |
| FB | fixed (moored) buoy |
| CMN | CMAN platform |
| TG | tide gauge station |
Statistics are not computed for platforms with the following callsigns: 'SHIP', 'BUOY', 'BBXX', 'PLAT', 'RIGG', or 'METEO'. These callsigns are not
unique (i.e. more than one platform may have the same callsign), so statistics for these callsigns would be meaningless.
Ship and Platform Names
The ship and platform names are obtained from several sources. Since callsigns and ship names change from time to time, a particular callsign
may be associated with 2 or more different names, or a ship name may be associated with several callsigns. Although we will update the names
file several times a year, we may not know which callsign/name is current.
A good web site for querying ship names and/or callsigns is that of the
Ship-Of-Opportunity Programme (SOOP), which is a joint program of the
WMO and the Intergovernmental Oceanographic Commission (IOC). On the OceanOps dashboard, click "Enter Dashboard". In the upper left
"Search" bar, one may enter a full or partial ship name or callsign, and an attempt will be made to find a match on either.
Additional Marine Data/Information
If you are seeking climatological marine data such as average temperature, wave heights, or prevailing winds for a particular oceanographic
region, please contact NOAA's National Centers for Environmental Information (NCEI).
For marine forecasts, please contact NOAA/NWS/NCEP's
Ocean Prediction Center (OPC).
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NCEP CENTRAL OPERATIONS (NCO) PLATFORM STATS
DECEMBER 2024
SEA-LEVEL PRESSURE FOR ALL HOURS
PLATFORM SHIP/PLAT. NAME TYPE NO. REPORTS MEAN DIFF SD DIFF # GROSS ERR
41082 FB 36 -9.2 0.3 0
DECEMBER 2024
AIR TEMPERATURE FOR ALL HOURS
PLATFORM SHIP/PLAT. NAME TYPE NO. REPORTS MEAN DIFF SD DIFF # GROSS ERR
AJXA2 UNKNOWN CMN 36 7.0 0.4 0
ERXA2 UNKNOWN CMN 36 5.8 0.4 0
GEXA2 UNKNOWN CMN 36 5.7 0.3 0
HMSA2 UNKNOWN CMN 36 6.7 0.4 0
JLXA2 UNKNOWN CMN 36 6.8 0.4 0
JMLA2 UNKNOWN CMN 36 6.8 0.3 0
LIXA2 UNKNOWN CMN 36 5.6 0.2 0
MRNA2 UNKNOWN CMN 36 6.8 0.4 0
MVXA2 UNKNOWN CMN 36 5.8 1.5 0
MXXA2 UNKNOWN CMN 36 6.5 0.3 0
NKXA2 UNKNOWN CMN 36 5.0 0.4 0
PAXA2 UNKNOWN CMN 36 5.5 0.4 0
PGXA2 UNKNOWN CMN 36 4.1 0.2 0
PTLA2 UNKNOWN CMN 36 6.8 0.5 0
RIXA2 UNKNOWN CMN 36 5.6 0.2 0
SCXA2 UNKNOWN CMN 36 6.2 0.5 0
SHXA2 UNKNOWN CMN 36 6.6 0.2 0
SKXA2 UNKNOWN CMN 36 5.9 0.7 0
STXA2 UNKNOWN CMN 36 4.4 0.5 0
41008 FB 36 -5.0 0.5 0
41083 FB 36 4.2 0.6 0
DECEMBER 2024
WIND DIRECTION FOR ALL HOURS
PLATFORM SHIP/PLAT. NAME TYPE NO. REPORTS MEAN DIFF SD DIFF # GROSS ERR
WYM9567 UNKNOWN SHP 18 44.0 34.1 2
ACXS1 UNKNOWN CMN 11 133.2 0.0 13
BABT2 UNKNOWN CMN 60 -38.4 7.4 0
BGXN3 UNKNOWN CMN 14 -141.3 0.0 10
BSLM2 UNKNOWN CMN 23 -63.5 27.1 1
CBLO1 UNKNOWN CMN 25 -97.4 6.5 10
DRSD1 UNKNOWN CMN 24 80.1 0.0 0
ELXC1 UNKNOWN CMN 4 177.7 4.6 20
FPTM4 UNKNOWN CMN 0 0.0 0.0 29
GDXM6 UNKNOWN CMN 24 -83.3 0.0 0
GIXA2 UNKNOWN CMN 36 36.7 14.9 0
GTLM4 UNKNOWN CMN 0 0.0 0.0 36
GTXF1 UNKNOWN CMN 24 -33.8 11.5 0
HAXA2 UNKNOWN CMN 0 0.0 0.0 36
HHLO1 UNKNOWN CMN 4 -91.4 0.0 32
HMRA2 UNKNOWN CMN 8 -160.8 41.1 16
HMSA2 UNKNOWN CMN 13 -118.9 43.2 23
ILOH1 UNKNOWN CMN 29 -83.6 11.3 13
JCRN4 UNKNOWN CMN 24 -52.0 18.9 0
JLXA2 UNKNOWN CMN 27 101.7 8.9 9
KEXA2 UNKNOWN CMN 34 -101.5 15.9 2
LONF1 UNKNOWN CMN 17 119.4 11.6 19
LPNM4 UNKNOWN CMN 0 0.0 0.0 60
MLSC1 UNKNOWN CMN 25 -157.0 8.3 35
MRNA2 UNKNOWN CMN 36 -54.5 5.0 0
MVXA2 UNKNOWN CMN 7 130.3 15.1 29
NWCL1 UNKNOWN CMN 60 -87.2 0.0 0
NWWH1 UNKNOWN CMN 12 -94.9 2.8 48
OMHC1 UNKNOWN CMN 0 0.0 0.0 60
OWXO1 UNKNOWN CMN 0 0.0 0.0 24
PAXA2 UNKNOWN CMN 36 -42.8 5.5 0
PCNT2 UNKNOWN CMN 12 -177.9 0.0 48
PGXA2 UNKNOWN CMN 36 -86.5 2.8 0
RIXA2 UNKNOWN CMN 36 66.1 4.5 0
RKXF1 UNKNOWN CMN 24 99.1 0.0 0
RLOT2 UNKNOWN CMN 60 -81.7 3.3 0
RPRN6 UNKNOWN CMN 30 -30.2 7.2 0
SANF1 UNKNOWN CMN 13 30.7 0.0 22
SCXA2 UNKNOWN CMN 2 93.3 0.0 34
SDRT2 UNKNOWN CMN 56 -93.7 7.0 4
SFXC1 UNKNOWN CMN 11 129.9 33.5 13
SHXA2 UNKNOWN CMN 35 90.5 5.8 1
SKXA2 UNKNOWN CMN 0 0.0 0.0 36
SLVM5 UNKNOWN CMN 35 61.6 0.0 0
SLXA2 UNKNOWN CMN 36 -88.0 0.0 0
STXA2 UNKNOWN CMN 36 47.0 13.7 0
TCMW1 UNKNOWN CMN 4 151.9 32.7 56
TIXC1 UNKNOWN CMN 15 147.4 18.0 9
TKEA2 UNKNOWN CMN 23 -62.2 18.1 13
WAXM3 UNKNOWN CMN 9 -148.5 0.0 15
WEXM1 UNKNOWN CMN 12 -175.9 7.6 12
WKXA1 UNKNOWN CMN 24 -93.9 4.3 0
YRSV2 UNKNOWN CMN 21 -44.6 32.1 3
41008 FB 36 -40.8 8.0 0
41053 FB 32 96.6 14.3 4
42012 FB 36 -34.6 12.6 0
44009 FB 33 140.7 12.5 3
44027 FB 36 80.5 0.0 0
44078 FB 36 -86.2 5.0 0
46014 FB 30 104.8 16.2 6
46025 FB 31 -51.9 34.5 5
46027 FB 36 -57.5 13.5 0
46053 FB 22 -159.0 8.7 14
46054 FB 14 83.9 18.0 22
46069 FB 36 90.2 4.6 0
46086 FB 22 -105.4 55.2 14
46087 FB 36 40.3 10.0 0
46097 FB 36 30.3 8.6 0
46121 FB 18 -72.7 34.6 18
51001 FB 36 40.5 12.1 0
51101 FB 36 48.7 11.6 0
DECEMBER 2024
WIND SPEED FOR ALL HOURS
PLATFORM SHIP/PLAT. NAME TYPE NO. REPORTS MEAN DIFF SD DIFF # GROSS ERR
AJXA2 UNKNOWN CMN 36 5.6 1.4 0
BIGM4 UNKNOWN CMN 36 -6.2 0.8 0
ERXA2 UNKNOWN CMN 36 7.9 0.8 0
HMRA2 UNKNOWN CMN 24 -9.3 1.1 0
HMSA2 UNKNOWN CMN 36 -9.5 0.9 0
KGCA2 UNKNOWN CMN 60 -5.3 1.4 0
LIXA2 UNKNOWN CMN 36 10.5 0.7 0
MRNA2 UNKNOWN CMN 36 6.5 1.0 0
NKXA2 UNKNOWN CMN 36 7.4 1.2 0
OWXO1 UNKNOWN CMN 24 -5.2 0.6 0
RIXA2 UNKNOWN CMN 36 11.4 0.9 0
SKXA2 UNKNOWN CMN 36 7.1 0.8 0
SLVM5 UNKNOWN CMN 35 -6.5 0.0 0
46087 FB 36 5.3 0.9 0
DECEMBER 2024
SEA SURFACE TEMP. FOR ALL HOURS
PLATFORM SHIP/PLAT. NAME TYPE NO. REPORTS MEAN DIFF SD DIFF # GROSS ERR
ELFA2 UNKNOWN CMN 33 12.5 0.2 0
NWCL1 UNKNOWN CMN 30 4.4 0.2 0
RLOT2 UNKNOWN CMN 30 10.5 1.0 0
41067 FB 53 -5.1 0.1 0
46087 FB 36 5.3 0.1 0
46088 FB 36 4.5 0.0 0
TOTAL NUMBER OF OBSERVATIONS FOR DECEMBER 2024 (EXCLUDING DUPLICATES
AND THOSE FROM CALLSIGN 'SHIP') WAS 15136. TOTAL NUMBER OF
OBSERVATIONS FROM CALLSIGN 'SHIP' (EXCLUDING DUPLICATES) WAS 0.
TOTAL NUMBER OF IDS WAS 1110.
