The first radio occultation measurements of the CHAMP (CHAllenging Minisatellite Payload) satellite using Global Positioning System (GPS) signals have been performed on February 11, 2001. By end April 2001 more than 3000 occultations were recorded. Globally distributed vertical profiles dry temperature and specific humidity are derived, which a set 438 is compared with corresponding global weather analyses. observed bias less ∼1 K above tropopause even 0.5 in altitude interval from 12 to 20...

GPS radio occultation measurements from CHAMP, GRACE‐A and FORMOSAT‐3/COSMIC are used to derive global information on small‐scale ionospheric irregularities such as sporadic E layers between January 2002 December 2007. The investigations based the analysis of amplitude variations signals. distribution shows strong seasonal with highest occurrence rates during summer in middle latitudes. long‐term data set CHAMP allows for first climatological studies, while coverage increases significantly...

Radio occultation events recorded on 28–29 July 2004 by a GPS receiver aboard the GRACE‐B satellite are analyzed. The stability of clock allows for derivation excess phase profiles using zero difference technique, rendering calibration procedure with concurrent observations reference obsolete. 101 refractivity obtained differencing and 96 calculated an improved single method compared co‐located ECMWF meteorological analyses. Good agreement is found at altitudes between 5 30 km average...

Analysis of atmospheric occultation data from the GPS Meteorology experiment has revealed that refractivity retrievals in lower troposphere were systematically smaller than those obtained with numerical weather prediction models. It been suggested bias was due to a combination multipath, critical refraction, and receiver tracking errors. In this paper, we show similar exists CHAMP SAC‐C describe characteristics based on over 6700 soundings October 2001. Retrievals using recently introduced...

The operational data analysis of the GPS radio occultation experiment aboard German CHAMP (CHAllenging Minisatellite Payload) satellite mission is described. Continuous Near-Real-Time processing with average time delay ∼5 hours between measurement and provision results demonstrated. A less than 3 reached for individual events. This made possible by using an operationally operated ground infrastructure, consisting a polar downlink station, globally distributed fiducial network, precise orbit...

Abstract. CHAMP (CHAllenging Minisatellite Payload) and GRACE (Gravity Recovery And Climate Experiment) formed a satellite configuration for precise atmospheric sounding during the first activation of GPS (Global Positioning System) radio occultation experiment aboard on 28 29 July 2004. 338 occultations were recorded both satellites, providing globally distributed vertical profiles refractivity, temperature specific humidity. The combined set shows excellent agreement with meteorological...

AB STRACTThe Tai wan/US FORMOSAT-3/COS MIC (FORMOsa SAT el lite mis sion -3/Con stel la tion Ob serv ing Sys tem for Me te o rol ogy, Ion sphere and Cli mate) sat con was suc cess fully launched on 14 April 2006.It is ex pected to le ver age the use of GPS (Global Po si tem) ra dio occultation data at mo spheric ion re search im prove global weather fore casts aid cli mate change lated stud ies.FORMOSAT-3/COS MIC, gether with Eu ro pean MetOp, Ger man CHAMP US/Ger GRACE-A lites, form a 9 pre...

The temperature structure in the tropical upper troposphere and lower stratosphere (UTLS) region is discussed based on Global Positioning System (GPS) radio occultation (RO) data from German CHAMP (CHAllenging Minisatellite Payload) satellite mission. Several climatologies for tropopause parameters radiosonde model analyses have been published recent years. Both sources suffer either low global coverage or poor vertical resolution. GPS RO technique, other hand, characterized by coverage,...

Abstract. In this study the global lapse-rate tropopause (LRT) pressure, temperature, potential and sharpness are discussed based on Global Positioning System (GPS) radio occultations (RO) from German CHAMP (CHAllenging Minisatellite Payload) U.S.-Argentinian SAC-C (Satelite de Aplicaciones Cientificas-C) satellite missions. Results with respect to seasonal variations compared operational radiosonde data ECMWF (European Centre for Medium-Range Weather Forecast) analyses. tropical...

This study discusses global tropopause height variabilities and trends based on zonal monthly mean GPS radio occultation data from the German CHAMP satellite mission for period May 2001–December 2007 (80 months). A gap of missing in July 2006 was filled with US‐German GRACE mission. increase between 26–44 m during observation (4–7 m/yr) is found depending binning method (5° or 10° latitude bands) used detection algorithm. The corresponding trend errors vary 19–21 m. inclusion quasi‐biennial...

[1] This paper evaluates the usage of reflected GPS signals for Earth observations to study changes sea level and sea-ice in remote sensing. In a coastal setup, ∼670 m above Disko Bay (Greenland), with different carriers L1 L2 were recorded. A method is presented that analyses interferometric phase between direct derives height reflecting surface. The analysis includes ray tracing an estimation signal coherence. It shown coherent reflections are related coverage. Absolute heights derived...

Abstract Sea surface topography observations are deduced from an airborne reflectometry experiment. A GNSS (Global Navigation Satellite System) receiver dedicated for was set up aboard the German HALO (High Altitude Long Range) research aircraft. Flights were conducted over Mediterranean about 3500 m above sea level. signal path model divided into large‐ and small‐scale contributions is used phase altimetry. The results depict geoid undulations resolve anomalies of topography. For whole...

An algorithm for correcting instrumental effects in polarization lidar studies is discussed. Cross-talk between the perpendicular and parallel channels imperfect of transmitted laser beam are taken into account. On basis Mueller formalism it shown that - with certain assumptions combined pulse, non-ideal properties transmitter receiver optics cross-talk can be described by a single parameter, which essentially overall system depolarization.

Within the first nine months following activation of GPS radio occultation experiment aboard low Earth orbiting satellite CHAMP, more than 25,000 events have been observed. A holographic analysis 3783 events, recorded between 14 May 2001 and 10 June 2001, reveals that in about 20–30% these received signal contains contributions from components reflected at Earth's surface. On basis geometrical ray tracing multiple phase screen calculations, characteristic frequency shifts holograms' power...

Improvements to the tropospheric ozone lidar at Jet Propulsion Laboratory Table Mountain Facility for measurements of profiles in troposphere and lower stratosphere, between approximately 5-and 20-km altitude, are described. The changes were primarily related receiver optical subsystems data-acquisition system. original 40-cm Cassegrain telescope was replaced with a faster (f/3) 91-cm Newtonian mirror. In focal plane this mirror, signal is divided into two parts by use separate fibers as...

Observations of polar stratospheric clouds (PSCs) from Ny Ålesund, Spitsbergen, have been examined to quantify the occurrence solid particles. The polarized backscatter ratio was found be a more sensitive indicator presence non‐spherical (solid) particles in PSC than aerosol depolarization, which approaches zero for containing large volume liquid droplets. analysis corroborates our previous finding that type Ia PSCs cannot composed nitric acid trihydrate equilibrium with gas phase, would...

The GPS (Global Positioning System) radio occultation experiment onboard the German CHAMP (CHAllenging Minisatellite Payload) satellite was successfully started in February 2001. By end of July 2001 more than 11,000 globally distributed vertical profiles atmospheric temperature were derived. Operational data processing is based on double difference method to correct for clock errors. This technique requires a continuous stream from global network ground stations. Termination Selective...

A global climatology of multiple tropopauses (MT) is discussed based on Global Positioning System (GPS) radio occultation (RO) data from the German CHAMP (CHAllenging Minisatellite Payload) and US‐Argentinian SAC‐C (Satelite de Aplicaciones Cientificas‐C) satellite mission for period May 2001–April 2005. In this study we present first detailed investigations about geographical temporal distribution MT during different seasons. The thickness layer between lowest (first) highest (last)...

This paper has been withdrawn.

The atmospheric propagation of GPS signals under multipath conditions and their detection are simulated. Using the multiple phase screen method, C/A‐code modulated L1 propagated through a spherically symmetric refractivity field derived from high‐resolution radio sonde observation. tracked by receiver implemented in software converted to profiles canonical transform technique Abel inversion. Ignoring noise assuming an ideal tracking behavior, true profile is reproduced better than 0.1% at...

GPS/MET radio occultation observations are analyzed with the holographic method. Using Multiple Signal Classification algorithm power spectra of 2038 holograms observed between 2 February and 16 1997 calculated. In about 28% L1‐band secondary frequency components found at levels 10–20 dB below main component. These interpreted as signatures GPS signals reflected Earth's surface. Results from geometrical ray tracing simulations support our interpretation.

Within the period of December 1992 to March 1993 lidar investigations stratospheric aerosols were performed at Ny‐Ålesund, Spitsbergen (79°N, 12°E). Backscatter signals wavelengths 353, 532 and 1064 nm depolarization in altitudes ranging from tropopause up 30 km analyzed. Throughout whole measurement we observed an aerosol layer volcanic origin lower stratosphere. Depolarization profiles suggest that consisted mainly liquid droplets. Comparison with model calculations indicate median...

This paper describes an altimetric method based on data recorded during experimental zeppelin flights over Lake Constance. Interferometric observations for this are obtained using a Master‐Slave receiver configuration. These contain the relative phasing of direct and reflected signals used altimetry. Separated antennas attached to record at slant elevation angles. Filtering is required remove contributions in geometry. Filtered corrected model, thus Doppler residuals retrieved. correction...

Validation studies of current GPS radio occultation experiments using meteorological analyses consistently report on a negative refractivity bias in the lower troposphere. End‐to‐end simulations including receiver's signal tracking process suggest that receiver‐induced phase deviations contribute to this observed bias. We propose heuristic retrieval algorithm based canonical transform and sliding spectral technique, which seems less susceptible errors than method. The approach is described...

Abstract. Within the German-Indonesian Tsunami Early Warning System project GITEWS (Rudloff et al., 2009), a feasibility study on future tsunami detection system from space has been carried out. The Global Navigation Satellite Reflectometry (GNSS-R) is an innovative way of using reflected GNSS signals for remote sensing, e.g. sea surface altimetry. In contrast to conventional satellite radar altimetry, multiple height measurements within wide field view can be made simultaneously. With...