|
NMOC Quarterly Summary July-September 2002
Summary of System Performance
Data Receipt
Analyses & Numerical Prediction |
About Products |
Map/Image/Chart Archives
NMOC requires a large variety of data as inputs to the various applications that run
operationally. The main types of data used in NMOC are shown in the following table,
along with the average daily number of reports received for each data type. The figures
for each month of the quarter indicated a slight increase in all major data types.
These values are obtained from the Real Time Database 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. METAR reports from foreign stations and METARAWS reports from local
stations are mostly for aviation use. The numbers in METAR does not cover
those received from foreign stations.
Locally derived cloud drift winds (LCL_CDW) from GMS 5 resumed normal operation
in July, and the daily number of observations went up from fewer than 3,000 in
the beginning of July to greater than 10,000 in the rest of the quarter. Data
received from NOAA 17, which became operational on 23 September will be corrected
for bias before it can be used in the model.
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, NMOC 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 five 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) to determine
if the mean and standard deviation values are beyond the defined threshold values,
over the whole month. The criteria 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).
Data coverage maps showing the origin of particular data types and the monitoring
reports, which can now be accessed by all GDPS centres participating in these
monitoring activities, are made available to the WMO Secretariat and to the focal
points of GTS data monitoring in RA V. The home page of the Quantity Monitoring
of the WWW at the WMO web server has inserted a link to our web page in the following
URL:
http://www.wmo.ch/web/www/ois/monitor/monitor-home.htm
(i) Daily data received in NMOC
| Text Data Types |
No. Daily |
Satellite Data Types |
No. Daily |
| SYNOP |
41,086 |
ATOVS (BUFR) |
99,106 |
| TEMP/PILOT |
2,044 |
ATOVS (SATEM) |
21,319 |
| SHIP/BUOY |
17,006 |
SATOB |
289,000 |
| AIREP/AMDAR |
22,116 |
SATOB_SST |
5,378 |
| BAYTHY/TESAC |
129 |
SAT_ALT |
53,877 |
| TRACKOB |
732 |
QuickSCAT |
1,111,839 |
| WAVEOB |
917 |
LCL_CDW |
9,982 |
| PAOB (AR and SH) |
827 |
GMS_MOIS |
38,806 |
| METAR/METARAWS |
14,282 |
TOVS1C |
2,316,658 |
| MDF |
1,774 |
AMV |
550,000 * |
| ONE MIN (AWS) |
102,264 |
| TEN MIN (AWS) |
6,419 |
| HYREP |
276 |
* estimated from test data base |
AVERAGE DAILY NUMBER OF REPORTS JULY TO SEPTEMBER 2002
OF VARIOUS DATA TYPES RECEIVED IN NMOC
|
ii) Time series of the average daily number of observations for some major
data types.
iii) Stations with mean sea level pressure observations identified as suspect.
iv) Data coverage maps for typical six-hour periods during the quarter. Current coverage
is available at
http://www.bom.gov.au/nmoc/Docs/Data_Monitoring/Obs_coverage_maps.shtml
|
