A5073644630- GNSS positioning and interference
- Geophysics and Gravity Measurements
- Ionosphere and magnetosphere dynamics
- Tropical and Extratropical Cyclones Research
- Meteorological Phenomena and Simulations
- Inertial Sensor and Navigation
- earthquake and tectonic studies
- Earthquake Detection and Analysis
- Atmospheric and Environmental Gas Dynamics
- Atmospheric aerosols and clouds
- Climate variability and models
- Soil Moisture and Remote Sensing
- Antenna Design and Analysis
- Environmental Monitoring and Data Management
- Geology and Paleoclimatology Research
- Ocean Waves and Remote Sensing
- Atmospheric chemistry and aerosols
- Context-Aware Activity Recognition Systems
- Geophysical Methods and Applications
- Seismic Waves and Analysis
- Energy Harvesting in Wireless Networks
- Oceanographic and Atmospheric Processes
- Antenna Design and Optimization
- Flow Measurement and Analysis
- Delphi Technique in Research
University Corporation for Atmospheric Research
1993-2018
National Central University
2001
UNAVCO
1993-1997
A 2‐hourly data set of atmospheric precipitable water (PW) has been produced from the zenith path delay (ZPD) derived ground‐based Global Positioning System (GPS) measurements. The PW are available every 2 hours 80 to 268 International GNSS Service (IGS, formally GPS Service) ground stations 1997 2004. accuracy IGS ZPD product is roughly 4 mm. An analysis technique developed convert on a global scale. Special efforts made deriving surface pressure (P s ) and water‐vapor‐weighted mean...
Global Positioning System (GPS) receivers, water vapor radiometers (WVRs), and surface meteorological equipment were operated at both ends of a 50‐km baseline in Colorado to measure the precipitable (PWV) wet delay line‐of‐sight GPS satellites. Using high precision orbits, WVR‐measured GPS‐inferred PWV differences between two sites usually agreed better than 1 mm. less precise on‐line broadcast orbits increased discrepancy by 30%. Data simulations show that measurements can provide mm‐level...
Atmospheric water vapor was measured with six Global Positioning System (GPS) receivers for 1 month at sites in Colorado, Kansas, and Oklahoma. During the time of experiment from 7 May to 2 June 1993, area experienced severe weather. The experiment, called "GPS/STORM," used GPS signals sense tested accuracy method meteorological applications. Zenith wet delay precipitable (PW) were estimated, relative Platteville, every 30 min five sites. At three these authors compared estimates PW...
We describe sensing of atmospheric column water vapor in near real‐time using the Global Positioning System (GPS). use predicted GPS orbits for automated computation vertical within 30 minutes data collection. Based on a 4 month comparison, agrees with radiosondes and radiometers 2 mm rms. Our are posted hourly at www.unavco.ucar.edu . They available assimilation numerical weather models other applications.
Abstract The upper-air sounding network for Dynamics of the Madden–Julian Oscillation (DYNAMO) has provided an unprecedented set observations studying MJO over Indian Ocean, where coupling this oscillation with deep convection first occurs. With 72 rawinsonde sites and dropsonde data from 13 aircraft missions, covers tropics eastern Africa to western Pacific. In total nearly 26 000 soundings were collected during experiment’s 6-month extended observing period (from October 2011 March 2012)....
Diurnal variations in atmospheric water vapor are studied by analyzing 30‐min‐averaged data of precipitable (PW) for 1996–2000 derived from Global Position System (GPS) observations 54 North America stations. Vertical structures the diurnal cycle examined using 3‐hourly radiosonde Lamont, Oklahoma, during 1994–2000 period. Significant PW found over most The (24 hour) cycle, S 1 , which explains 50% subdaily variance, has an amplitude 1.0–1.8 mm central and eastern United States summer is...
The sensing of precipitable water (PW) using the Global Positioning System (GPS) in near Tropics is investigated. GPS data acquired from Central Weather Bureau's Taipei weather station Banchao (Taipei), Taiwan, and each nine International Service (IGS) stations were utilized to determine independently PW at site 18 24 March 1998. Baselines between other range 676 3009 km. determined observations for baseline cases are compared with measurements by a dual-channel vapor radiometer (WVR)...
A series of water vapor intensive observation periods (WVIOPs) were conducted at the Atmospheric Radiation Measurement (ARM) site in Oklahoma between 1996 and 2000. The goals these WVIOPs are to characterize accuracy operational observations develop techniques improve measurements. initial focus experiments was on lower atmosphere, for which goal is an absolute better than 2% total column vapor, corresponding ~1 W m−2 infrared radiation surface. To complement instruments during WVIOPs,...
We have conducted two experiments to determine precipitable water vapor (PWV) and sea surface heights from a cruising ship in the open ocean. During first experiment (July 7–13, 02) GPS radiosonde PWV agreed at 2 mm rms level. second (Aug 23–30, 03) compared 1.5 (1.1 high bias) with eight ship‐launched radiosondes 2.8 (1.2 ship‐based radiometer (WVR). estimate that vertical position of antenna ocean was determined better than 10 cm rms. After correcting for tides estimated cruise CARIB97...
Abstract The NASA Goddard Space Flight Center (GSFC) Scanning Raman Lidar (SRL) participated in the International H2O Project (IHOP), which occurred May and June 2002 midwestern part of United States. SRL received extensive optical modifications prior to during IHOP campaign that added new measurement capabilities enabled unprecedented daytime water vapor measurements by a lidar system. Improvements were also realized nighttime upper-tropospheric measurements. other for deployment included...
Abstract This study presents, for the first time ever, occulting signals of Global Navigation Satellite Systems (GNSSs) acquired at two polarizations from a Low Earth Orbiter, and it shows that they sense heavy precipitation. The data sets are obtained early stages Radio Occultation Heavy Precipitation experiment aboard PAZ satellite, launched in February 2018 activated May 2018. Preliminary calibration algorithms applied to remove other systematic effects, resulting vertical profiles...
Abstract The variation of precipitable water vapor (PW) over the continental United States is examined at various time scales using spatial maps a column-averaged mixing ratio (CAMR) that derived from integrated column PW both observations and reanalysis data. CAMR are generated utilizing measurements obtained network ground-based global positioning system (GPS) receivers North American Regional Reanalysis (NARR) span 4 yr (February 2009–January 2013). effect topography on mitigated by...
Delay of the Global Positioning System (GPS) signal due to atmospheric water vapor is a major source error in GPS surveying. Improved vertical accuracy important for sea level and polar isostasy measurements, geodesy, normal fault motion, subsidence, earthquake studies, air ground‐based gravimetry, ice dynamics, volcanology. We conducted survey using radiometers (WVRs) pointed toward satellites correct azimuthal variations vapor. report 2.6 mm precision on 50‐km baseline 19 solution days....
We report on precipitable water vapor (PWV) from a Global Positioning System (GPS) receiver and surface meteorological network during the 2004 North American Monsoon Experiment (NAME) in northwestern Mexico. The monsoon onset is evident as large PWV increase over several days beginning July 1. Data Sierra Madre Occidental (SMO) foothills reveal dynamical transition mid‐August smaller, sub‐synoptic scale to larger, synoptic moisture structure. During Sub‐synoptic phase SMO foothills, positive...
A comparison of precision campaign GPS data from 1995 and 2004 10 benchmarks on the eastern Snake River Plain (eSRP) has revealed that province moved 2.8 ± 0.3 mm/a to SW (232.4 6.3°) relative a fixed North American reference frame. The had no measurable displacement one another at resolution during 9‐annum study, evidence moves as rigid, nonextending block. This scenario is supported by aseismic nature lack horizontal stress in boreholes. However, an additional small component intraplain...
Slant wet delay (SWD) measurements from a ground‐based GPS observation network provide accurate, high‐resolution moisture information for mesoscale analysis. In this study, we compared SWD simulated 9‐km MM5 model in prefrontal squall line event against actual observations by NOAA's network. We found that the simulation did not capture abrupt changes and small‐scale variations observed nonisotropic component of slant delays associated with line. This result suggests can be very useful improving