NOTICE DATED SEPTEMBER, 2003:

On October 1, 2003, at 0000 Universal Time Coordinated, the following National Weather Service upper-air stations will begin use of the Sippican LORAN Microsonde with a chip thermistor (i.e., temperature sensor):

Station and WMO Number

Albany, NY, 72518

Wallops island, VA, 72402

Charleston, SC,  72208

These stations will apply a solar radiation correction to the temperature data prior to its transmission to data users. After the September 30, 2003, 1200 UTC observation, the above stations will stop all operational use of the Sippican LORAN Microsonde with the short-rod thermistor. This radiosonde type did not apply any solar or infra-red correction to the temperature data prior to its transmission.

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NOTICE DATED APRIL, 1998:

Beginning with the 0000 Universal Time Coordinated sounding on June 1, 1998, the NWS will begin use of the Vaisala RS80-57H radiosonde at 35 upper-air stations. Use of VIZ radiosondes at these sites will be discontinued. This will bring the total number of NWS stations using Vaisala radiosondes to 60. The remaining 32 stations in the NWS network will continue to use VIZ radiosondes. A list of stations implementing the Vaisala radiosonde is attached.

Radiation corrections will be applied to Vaisala temperature data before it is disseminated, which is common practice in other countries using this radiosonde type. The NWS will use the most current Vaisala radiation correction algorithm, RSN93, for applying these corrections. The policy of not correcting data transmitted from the remaining VIZ-B and VIZ-B2 radiosonde upper-air sites will continue.

NWS UPPER-AIR STATIONS SWITCHING
FROM THE VIZ-B2 TO the VAISALA RS-80-57H RADIOSONDE
EFFECTIVE JUNE 1, 1998

*Anchorage will switch from the VIZ-B model radiosonde

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NOTICE DATED APRIL, 1997

On June 1, 1997, beginning with the 0000 Universal Coordinated Time sounding, the NWS will switch from the VIZ-B to the VIZ-B2 radiosonde at 57 upper-air sites, in the conterminous United States.  The list of sites that will implement VIZ-B2 radiosondes is attached.

The VIZ-B2 replaces the decades old mechanical baroswitch pressure sensor found in VIZ-B radiosondes with a capacitance pressure sensor, that provides improved performance. Furthermore, factory calibration and data conversion algorithms of the relative humidity and temperature sensors used with this new radiosonde have been improved, allowing for more accurate measurements. In accordance with NWS policy, VIZ-B2 temperature data transmitted over the Global Telecommunication System and archived at the National Climatic Data Center will not be corrected for solar and infra-red radiation.

NWS UPPER-AIR STATIONS SWITCHING
FROM THE VIZ-B TO THE VIZ-B2 RADIOSONDE
EFFECTIVE JUNE 1, 1997

Note: Eight stations will continue using VIZ-B radiosondes.  These stations will switch to the VIZ-B2 when supplies of the VIZ-B are depleted sometime in 1998.  The stations are as follows:

Anchorage, AK
Annette Island, AK
Point Barrow, AK
Saint Paul Island, AK
San Juan, PR

Pacific Islands:
Guam
Hilo, HI
Majuro Island

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NOTICE DATED OCTOBER, 1995:

The implementation of the Vaisala RS80-56 radiosonde at  NWS upper-air sites has been delayed from November 1 to December 1, 1995, for a portion of the 25 sites planned to utilize this radiosonde. Attached is a station list of sites that will use Vaisala radiosondes and their scheduled implementation date. The implementation times will begin with the 0000 Universal Coordinated Time sounding on the first day of the respective months.

Radiation corrections will be applied to Vaisala temperature data before it is disseminated, which is common practice in other countries using this radiosonde type. The NWS will use the most current Vaisala radiation correction algorithm, RSN93, for applying these corrections. The policy of not correcting data transmitted from the remaining VIZ-B radiosonde upper-air sites will continue.

NWS UPPER-AIR STATIONS SWITCHING
FROM THE VIZ-B TO THE  VAISALA RS80-56 RADIOSONDE
EFFECTIVE NOVEMBER 1, 1995

NWS UPPER-AIR STATIONS SWITCHING
FROM THE VIZ-B TO THE  VAISALA RS80-56 RADIOSONDE
EFFECTIVE DECEMBER 1, 1995

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