Figure 1. Web traffic at MDC in the last six months.
In the last six months there was a lot of Internet traffic at the MDC. On average, the MDC had 431 request per day or 78500 accesses in the last six months. Figure 1 shows the daily traffic in the period February 25 to August 25, 1997. The minimum was 48 and the maximum 1582 accesses per day. You can also recognise the weekly structure with working days and weekends.
Figure 1. Web traffic at MDC in the last six months.
In the MAP member area only, there were 8400 downloads of radar and satellite images and 2656 ORACLE database request. In this observation period there were 3894 different workstations which accessed the MAP Webserver at least once. We had a dozen workstations with more than 2000 accesses.
If you have problems to reach the MDC by Internet, there are the following possibilities to locate the error:
If you want to get one day of high resolution data, you must complete the Web Browser form with the following information: in the startdate field the date of your data request and in the enddate field the date plus one day (e.g. date between 10.11.92 (DD.MM.YY) and 11.11.92 (DD.MM.YY)).You have to add one day because the time of the inserted date is set to 00:00 by the database.
If you do a database request for any data on your Web Browser and you receive the message "The Server had an internal error and could not process the request" after a long time of waiting, you have the possibility to get the data directly by FTP. This error appears only when the MAP ORACLE database is very busy. You must go back one page on your Web Browser to find out the name of your datafile. On the Web Browser form you will find the name under "File output options: Filename". You can try to fetch the data directly by FTP after a while (1 hour). On your Web Browser you must type in the following command: "ftp://www.map.meteoswiss/pub-file/ filename " If you use an FTP tool, you must first connect to the MAP FTP Server (map.ethz.ch) with anonymous login. Now you must type in the command "get /pub/map/mapoutput/ filename " for fetching the datafile. But remember that you to not get any directory information at this FTP site! You must know exactly the datafile name for fetching the data.
If you downloaded precipitation data of GTS stations from the MAP Data Centre before August 1997 some of your data may be wrong and you should download them again. The warning concerns only data of the SYNOP network (GTS) and only precipitation. If you are not using data of this category you can ignore this message.
GTS precipitation data is provided by the MAP Data Centre as background coverage in the larger MAP-domain (Europe and North Africa). Data of this category is retrieved by the Data Centre from original SYNOP-messages stored in the MARS archive at ECMWF. Recently, we have noted that the coding for the timeperiod of rainfall is not used everywhere according to the WMO regulations in the original messages. Apparently many countries/stations have applied there own 'rules' for coding. Hence, daily totals calculated with the assumption that official WMO coding was used, may be incorrect. This has become evident from inconsistencies in the reports for overlapping time periods.
In order to provide reasonable SYNOP precipitation coverage on MAP Data Centre a semi-automatic procedure has been developed which estimates the coding-rules at individual stations. The newly calculated precipitation series for the MAP seasons have now been introduced into the Database. As mentioned, if you are using SYNOP precipitation data you should reaccess it since your earlier download was likely to have wrong data.
Here we emphasise that these errors only concern the low resolution GTS data and only precipitation. There is no need to reload data from the high-resolution data section of the database, or other than precipitation GTS surface data!
We apologise for not having recognised these problems earlier.
If you require further information, please contact Christoph Frei or
the MAP Data Centre.
Remark: If you use precipitation data from countries that have data in the low and high resolution area, it is recommended to use the high resolution data. The primary (country) provider sent the high resolution precipitation data to the MDC, while the low resolution data source is the MARS archive at ECMWF. If you compare low and high resolution data of the same station, you may find differences.
