Zenith Tropospheric Delay Eastern Asia	Precipitable Water Vapor Within CFW Forecast Domain of Asia

The map images above show the near real-time ZTD (left) and PWV (right) at IGS hourly stations in the Estern Asia. It is processed at GPS Solutions Inc., Boulder, CO. PWV is mapped from forecast pressures in the domain from Clock for Weather (CFW) GPS enhanced forecast system. Efficient near real-time processing of tropospheric delay and other GPS estimates such as coordinate and inospheric delays are possible with RTNet software with real-time. The IGS near real-time PWV data is available from Nippon GPS Solutions (NGS), Tokyo, Japan.

Schematic diagram showing efficient near real-time processing with RTNet.

RTNet can handle batch data (30 min. data hourly data with any latency). and processing is resumed in the last epoch of batch data, and restart as soon as new data shows up.
We use Click for Weather forecast system developed by GPS Solutions Inc., and forecast pressure generally agrees with observed pressure within 1.5 hPa rms up to one day forecast. Because the forecast is upodated every 6 hours, we can use newest forecast pressure every time. That means that We don't depend on surface meteorological observation to map ZTD intp PWV, and don't need to worry about painful calibrations of in-situ pressure sensor.

IGS hourly stations in eastern Asia.

Note that not all stations are available each time within 3 hour latency setting.

6 hour ZTD forecast from Clock for Weather system in the eastern asian region.