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NMOC Quarterly Summary April-June 2002
Summary of System Performance
Data Receipt
Analyses & Numerical Prediction |
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NMOC requires a large variety of data as inputs to the various applications that are run. The
main types of data used in NMOC are shown in the following table, along with the average daily
number of reports received of each data type. The figures are obtained over the 15-day sampling
period 16-30 June. These values are obtained from the Real Time Data Base that captures data
from both domestic and international circuits.
Not all data types are used for input to the models. The high resolution data from the one
minute and ten minute observations from the automatic weather stations (AWS) and the surface observations transmitted
from the electronic field book (EFB) in meteorological data format (MDF) are essentially for climate use only.
The numbers in METAR does not cover those received from foreign stations. The lack of a complete ICAO
station identifier in the stations dictionary is prohibiting the decoding of METAR reports received from foreign
stations.
There were no major deficiencies in the amount of data collected over the quarter.
However, the locally derived cloud drift winds (LCL_CDW) from the satellite were significantly down due
to a system crash, which happened in March. Problems continue with the reduced time schedule of the
Geostationary Meteorological Satellite GMS-5 in the Southern Hemisphere.
Data coverage maps overleaf show the origin of particular data types. The maps show the
coverage during a typical six-hour period at 12 UTC for SYNOP/SHIP and TEMP/PILOT.
As the designated lead centre for monitoring the quality of land surface observations
in Region V (South-West Pacific), NMOC produces monthly lists of stations considered to be reporting
suspicious observations in mean sea level pressure and geopotential height for all Regions. In
addition, the centre also produces monthly global monitoring reports for ship and buoy observations
and a 6-monthly consolidated list of suspect stations, including rigorous investigations into the
possible reasons of the large pressure biases at the suspect stations in Region V.
Based on the monthly lists of the monitoring reports during the quarter, the
mean sea level pressure of three stations in Region V were identified as possibly suspect. The
monitoring method to distinguish a station as 'suspect' is to compare the deviation of the
observations from the GASP first-guess fields (Observation-Guess) and determine if the mean and
standard deviation values are beyond the defined threshold values, over the whole month. The
c iteria for quality control follow the guidelines of the WMO Manual on the Global Data Processing
System (GDPS), which defines various limits to be used for a number of statistics including gross
error, the mean value and standard deviation of the bias (O-G).
(i) Daily data received in NMOC
| Text Data Types |
No. Daily |
Satellite Data Types |
No. Daily |
| SYNOP |
40,379 |
ATOVS (BUFR) |
92,397 |
| TEMP/PILOT |
2,005 |
ATOVS (SATEM) |
20,484 |
| SHIP/BUOY |
18,120 |
SATOB |
270,238 |
| AIREP/AMDAR |
21,217 |
SATOB_SST |
5,593 |
| BAYTHY/TESAC |
147 |
SAT_ALT |
52,385 |
| TRACKOB |
730 |
QuickSCAT |
1,114,522 |
| WAVEOB |
876 |
LCL_CDW |
2,008 |
| PAOB (AR and SH) |
792 |
GMS_MOIS |
33,380 |
| METAR/METARAWS |
14,378 |
TOVS1C |
2,309,107 |
| MDF |
1,692 |
US ACARS |
80,000 * |
| ONE MIN (AWS) |
91,319 |
AMV |
550,000 * |
| TEN MIN (AWS) |
5,486 |
| HYREP |
264 |
* estimated from test data base |
AVERAGE DAILY NUMBER OF REPORTS FOR 16-30 JUNE 2002
OF VARIOUS DATA TYPES RECEIVED IN NMOC
ii) Stations with mean sea level pressure observations identified as suspect.
iii) Data coverage maps for typical six-hour periods during the quarter.
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