The GPS/ MET (Global Positioning System/ Meteorology) program utilizes microwave signals transmitted by the CPS satellite system and received at a LEO (Low Earth Orbiting) satellite to monitor the Earth's ionospheric and atmospheric refractivities through a process known as an atmospheric limb so... Show moreThe GPS/ MET (Global Positioning System/ Meteorology) program utilizes microwave signals transmitted by the CPS satellite system and received at a LEO (Low Earth Orbiting) satellite to monitor the Earth's ionospheric and atmospheric refractivities through a process known as an atmospheric limb sounding. The delay and bending of a radio path (caused by refractivity and refractivity gradients between the satellites and deemed excess atmospheric phase delay), are calculated, along with the induced orbital motion effect in the CPS phase data. Knowing the position and velocity of each satellite, the orbital motion effect is removed from the occulted CPS satellite phase data, leaving the excess atmospheric phase delay. This, along with the position and velocity of the LEO and CPS satellites, is then used by an Abel Transform software package to convert the data into refractivity values as a function of height for the atmosphere. As the LEO satellite has not been launched at the time of this SEP (Summer Employment Program) project, simulated runs were created to perform error analysis on the inversion software. One of the objectives of this project was to create a "noise generator" to simulate post-launch errors which will be present in the operational data product. Realistic refractivity profiles of the atmosphere were generated and used to further test and compare the inverter software's ability to compute refractivities from strong temperature and moisture gradients. Analysis was done by examining the means and standard deviations of the errors obtained by taking the difference between the truth and computed refractivities. From this error analysis we gained a realistic picture of the inverter's capability to handle noise and its ability to utilize real-time data to calculate the atmosphere's refractivity profile. It is hoped that these real-time refractivity profiles will be assimilated into global climate and weather models to improve weather forecasting abilities. It is also hoped that temperature and moisture profiles will be calculated from the computed refractivity profiles. Show less
