Atmospheric Water Vapor Content Inferred From GPS Data and Compared to a Global NWP Model and a Regional Climate Model

• Radio based space geodetic methods are affected by the water vapor in the atmosphere.The velocity of the propagating signal is reduced, depending on the value of the refractiveindex. The atmospheric water vapor content, sometimes also called Integrated WaterVapor (IWV), can be inferred from the estimated propagation delay, or the excess propagationpath often expressed in units of length. The observations are relative measurementsof time, which makes the methods interesting from a calibration point of view - since timeis the physical parameter that we can measure with the highest accuracy.Since water vapor is difficult, and costly, to measure with a high temporal and spatialresolution, given its characteristics of variability, researchers in the atmospheric scienceshave shown interest in using data from already existing ground-based continuously operatingGPS receivers. Time series of the IWV from specific sites are now longer than tenyears. For example, 20 sites in the Swedish GPS network have produced continuous datasince 1993/1994. In addition to GPS also additional global navigational satellite systems(GNSS), such as the European Galileo and the finalization of the Russian GLONASS, willin the future significantly improve the spatial sampling of the atmosphere, and also reducethe relative influence of orbit errors for individual satellites.We have analyzed ground-based GPS data acquired in Europe and Africa over the period2001-2006. IWV results from the GPS data analysis are compared to the global NumericalWeather Prediction (NWP) models from the European Center for Medium RangeWeatherForecasting (ECMWF) as well as the regional climate model of the Rossby Center.The overall goal for the possible use of GNSS data in climate research is to determine towhich extent these independent data can be used to discriminate between different climatemodels - both in terms of absolute values as well as long term trends - thereby improvingthe quality of the models and increasing the probability to produce realistic scenarios ofthe future climate.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Elektroteknik och elektronik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Electrical Engineering, Electronic Engineering, Information Engineering (hsv//eng)

TEKNIK OCH TEKNOLOGIER  -- Elektroteknik och elektronik -- Annan elektroteknik och elektronik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Electrical Engineering, Electronic Engineering, Information Engineering -- Other Electrical Engineering, Electronic Engineering, Information Engineering (hsv//eng)

Publikations- och innehållstyp

kon (ämneskategori)

vet (ämneskategori)