NOTIFICATION FROM NEW ZEALAND: A PERIOD OF DAYLIGHT SAVINGS FROM 1400UTC 27 SEPTEMBER 2014 TO 1400UTC 4 APRIL 2015 WILL BE INTRODUCED DURING WHICH PERIOD ALL UPPER-AIR SOUNDINGS WILL BE CARRIED OUT ONE HOUR EARLIER, BUT SYNOP REPORTS WILL CONTINUE AT UTC TIMES.
Some countries shifts the time of observations for main synoptic hours, namely 00Z, 06Z, 12Z, and 18Z, by operational reasons such as daylight saving time. That is so important thing that it is to be announced by METNO A.
But its meaning or degree of damage has changed a lot recently.
When President Kennedy of the United States called for international cooperation of meteorology, which became the World Weather Watch later, the primary usage of real-time synoptic reports was human-plotted charts. Human forecaster is the only method to know the future. There were very early NWP (numerical weather prediction) works but operation could rely little on the computer that time which was 100000 times slower than iPhone 6. At that time the one-hour-early report was really frustrating for analysis, which meant drawing contours by pencil and rubber.
Now the situation has totally changed. Decades ago NWP became the primary method of at least tomorrow's forecast. Human forecaster still watches radars and satellites, but that is mainly for short-term alerts, for which twelve-hourly soundings have smaller impact. In the last decade the four-dimensional assimilation became common in worlds NWP centers, by which all observations in a several hours timeframe are equally used. For upper-air sounding, the frequency and regularity are serious requirements, but one hour early report does not matter so much as in 1960s.
Weeks ago I've been to WMO's CBS Technical Conference in Paraguay, at which many works of new framework of observing systems were reported. Behind the works there is change of situation as mentioned above.
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