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We present results of combining occultation refractivity profiles from GPS/MET with ECMWF global analyses in a 1DVar framework in order to separate the wet and dry contributions to refractivity and assess their impact on the analyzed temperature, surface pressure and specific humidity fields.
In recent years, the Global Positioning System (GPS) has been exploited via radio occultation techniques to obtain profiles of refractivity, temperature, pressure and water vapor in the neutral atmosphere and electron density in the ionosphere.
The radio occultation technique has been used to characterize planetary atmospheres since the 1960's spanning atmospheric pressures from several bars to 16 microbars.
We present a generalized raytracing inversion scheme which can be used when the occultation data is taken from within or outside the atmosphere.
None given. Paper deals with radio occultation measurements using the Global Positioning System (GPS).
This paper summarizes the latest results on the morphology of the near-Sun solar wind obtained from radio occultation measurements, and their impact on the planning and conduct of a mission to the Sun such as Solar Probe.
The compton Gama-Ray Observatory's Burst and Transient Source Experiment (BATSE) has a powerful capability to provide nearly uninterrupted monitoring in the 25keV--2MeV range of cosmic point sources using occultation by the Earth.
This paper talks about how 2 spacecraft launches add two new instrumetns for climate monitoring and GPS radio occultations.
ROCSat-3's primary instrument is the GPS Occultation Receiver (GOX) and is based on the Jet Propulsion Laboratory's (JPL) proven BlackJack GPS Receiver. The COSMIC GOX receivers will demonstrate an important new operational data type for near-real-time assimilation into weather models by providing over 2500 atmospheric profiles per day with a global distribution.
The vertical temperature structure of the tropical atmosphere has been explained as controlled by the combined effect of three green house gases: water vapor, carbon dioxide, and ozone. Absorption by water vapor of the light reflected off the Earth's surface would determine the temperature lapse rate in the lower troposphere up to the bottom of the Tropical Transition Layer (TTL); radiative absorption by carbon dioxide would dominate the temperature lapse rate between the bottom of the TTL and the coldest point in the upper-troposphere, the cold point tropopause (CPT), and; absorption of incoming solar radiation by ozone would control the temperature above the CPT. The TTL region can thus be very sensitive to changes in the relative abundances of these greenhouse gases. In this contribution we describe the seasonal evolution of temperature profiles in the TTL and their longitudinal structure using GPS radio occultation.
An assessment of open-loop tracking occultation data from Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) is presented.
An occulter is an optical element which is placed in front of the telescope to block most of the light from a star before it reaches the optics inside, without blocking the planet.In our case, we use two spacecraft ying in formation: First has its edge shaped to cancel the starlight Second is the telescope which images the star and planet
We can extend robustly the radio occultation data record by 6 years (+60%) by developing a singlefrequency processing method for GPS/MET data. We will produce a calibrated data set with profile-byprofile data characterization to determine robust upper bounds on ionospheric bias. Part of an effort to produce a calibrated RO data set addressing other key error sources such as upper boundary initialization. Planned: AIRS-GPS water vapor cross validation (water vapor climatology and trends).
We present a design for a 4 U (20 cm 20 cm 10 cm) occultation-viewing laser heterodyne radiometer (LHR) that measures methane (CH4), carbon dioxide (CO2) and water vapor(H2O) in the limb that is designed for deployment on a 6 U CubeSat. The LHR design collects sunlight that has undergone absorption by the trace gas and mixes it with a distributive feedback (DFB) laser centered at 1640 nm that scans across CO2, CH4, and H2O absorption features. Upper troposphere lower stratosphere measurements of these gases provide key inputs to stratospheric circulation models: measuring stratospheric circulation and its variability is essential for projecting how climate change will affect stratospheric ozone.
Ionospheric scintillation can significantly degrade the performance and the usability of space‐based communication and navigation signals. Characterization and prediction of ionospheric scintillation can be made from the Global Navigation Satellite System (GNSS) radio occultation (RO) technique using the measurement from a deep slant path where the RO tangent height (ht) is far below the ionospheric sources. In this study, the L–band S4 from the RO measurements at ht = 30 km is used to infer the amplitude scintillation on the ground. The analysis of global RO data at ht = 30 km shows that sporadic–E (Es), equatorial plasma bubbles (EPBs), and equatorial spread–F (ESF) produce most of the significant S4 enhancements, although the polar S4 is generally weak. The enhanced S4 is a strong function of local time and magnetic dip angle. The Es–induced daytime S4 tends to have a negative correlation with the solar cycle at low latitudes but a positive correlation at high latitudes. The nighttime S4 is dominated by a strong semiannual variation at low latitudes.
In this paper we provide an evaluation of the backpropagation method on simulated occultations as well as data collected by CHAMP and SAC-C.
A key element in the Eclipse coronagraph is the apodized occulting spot. For exo-planet detection in the presence of a sun-like star, the intensity transmittance at the center of the spot is specified to be less than 1X10***sup-8***.
Geopotential heights of constant pressure surfaces are retrieved from GPS radio occultation data. In order to assess accuracy, a subset of data obtained by GPS/MET during spring and summer 1995 are compared to the output of the ECMWF global model...