Retrieval of Trace Gas Concentrations from Lunar Occultation Measurements with Sciamachy on Envisat

Rozanov, H. Bovensmann, and J.P. Burrows Abstract SCIAMACHY (Scanning Imaging Absorption Spectrometer for Atmospheric Chartography) is a UV-Vis-NIR spectrometer on-board ENVISAT, dedicated to measure atmospheric trace gas distributions in nadir, limb, and occultation geometries. In occultation mode, SCIAMACHY tracks the rising Sun or Moon directly through the atmosphere. Dividing the atmospheric measurements by extraterrestrial references gives transmission...

GPSRO Capabilities

The SAC-C, CHAMP (since 2001), GRACE, and COSMIC satellites (since 2002 and 2006, respectively) provide atmospheric parameters retrieved during RO events such as temperature, pressure, water vapor, and geopotential height. The obtained profiles have vertical resolutions ranging from 0.5 km in the troposphere up to 1.4 km in the stratosphere (Kursinski et al. 1997) (nevertheless, the data are usually interpolated every 200 m) and horizontal resolution of 150 km along each LOS. The perigee of the...

Summary and Conclusions

Currently, KOMPSAT-5 is in a detailed design phase. KASI is in charge of developing of the AOPOD system, which includes a dual frequency GPS receiver and a laser retro reflector. A dual frequency GPS receiver will be used for generation of POD data and occultation science data. For processing the occultation data, KASI is developing KROPS. The first version of KROPS will be released by the end of year 2008. Since KOMPSAT-5 has only one ground station, KOMPSAT-5 contacts the ground station twice...

Conclusions and Future Work

The objective of this study is to demonstrate the potential to use GPS RO and AMSU MSU data to construct consistent climate temperature records. This is done by using the COSMIC synthetic AMSU Tbs as calibration references to inter-calibrate AMSU Tbs from N15, N16, and N18. Our analysis led to the following conclusions. 1. The COSMIC synthetic AMSU Tbs are highly correlated with AMSU Tbs. The mean Tb biases for AMSU-COSMIC pairs over the 60 N to 90 N zone and the 60 S to 90 S zone are very...

Laser Retro Reflector Array

A Laser Retro Reflector Array (LRRA) will be used for POD validation of KOMP-SAT-5. The KOMPSAT-5 LRRA developed by GFZ (GeoForschungsZentrum) is shown in Fig. 6. The KOMPSAT-5 LRRA has four cube corner prisms mounted in a compact frame. A bracket will be used to compensate the tilt angle of the spacecraft and ensuring a better field of view. Figure 7 shows the configuration of the LRRA. R.A of Ascending Node (deg) 339.73

Testing Feedbacks with Clarreo

If climate models accurately reproduce climate sensitivity, one way to ascertain whether they do so for the correct physical reasons is to divide climate response according to feedbacks. CLARREO should be capable of doing so because individual feedbacks have distinctive spectral signatures in the thermal infrared and visible wavelengths. GNSS occultation should play an important role because of its insen-sitivity to clouds it might resolve the cloud-surface temperature ambiguity inherent to...

Comparison of TLS Temperatures

Results of the comparison of synthetic CHAMP TLS temperatures to MSU AMSU records from UAH and RSS as well as to synthetic ECMWF and HadAT2 TLS temperatures are presented in Fig. 4 for the tropical region. SAC-C, GRACE, and COSMIC anchor point months are also shown, their TLS temperatures closely match CHAMP temperatures within the sampling error range of < 0.3 K (Fig. 4a). Regarding absolute TLS temperatures (Fig. 4a), ECMWF agrees best with RSS until January 2006, then it closely follows...

Forward Model of the Atmosphere Transmittance

Extinction of the solar emission by the atmosphere at a given wavelength X is deduced from the well-known Beer-Lambert (or Bouguer) law where I0(X) is the solar spectral irradiance at wavelength X, I(X) is the solar spectral irradiance after absorption by the atmosphere, and t (X), the optical thickness, which is defined by N is the number of active atmospheric constituents, the integration is performed over the optical path (with L, the distance between the Sun and the satellite measured along...

Sim Vis The Simulation Visualization Tool

SimVis is a research software framework that was developed for the interactive visualization and analysis of complex (4D, multi-variate) data resulting from computational fluid dynamics (CFD) simulations, e.g., the injection and combustion processes in car engines (Doleisch et al. 2005 Schmidt et al. 2005). The key elements of this software framework such as interactive feature specification and visualization, brushing, linked views, focus+context visualization, derived data, or different types...

Using the Calibrated AMSU Data to Calibrate Other Overlapped AMSU Measurements

From the previous section, we know the best fit for N16 Tbs and COSMIC data for one particular month (in this case, July 2007, e.g., Fig. 2b ), which is TbCOSMIC_N16 0.984 TbAMSU 16 + 3.81, (1) and the best fit for N15-N16 pairs (Fig. 3a ) is TbAMSU_N16 1.001 TbAMSU_N15 0.3. (2) To use the COSMIC-calibrated N16 Tbs to calibrate N15 Tbs is to construct the calibration coefficients for COSMIC-N15 pairs using Eq. (1) and Eq. (2), and we have TbCOSMIC 15 16 0.984 TbAMSU 15 + 3.51. (3) The...

Springer

Andrea Steiner Wegener Center for Climate and Global Change (WegCenter) University of Graz Leechgasse 25 8010 Graz and Institute for Geophysics, Astrophysics, and Meteorology (IGAM) University of Graz Universitatsplatz 5 8010 Graz Austria Dr. Ulrich Foelsche Wegener Center for Climate and Global Change (WegCenter) University of Graz Leechgasse 25 8010 Graz and Institute for Geophysics, Astrophysics, and Meteorology (IGAM) University of Graz Universitatsplatz 5 8010 Graz Austria Barbara...

Occultation Data Processing System

KASI is in charge of the scientific research using KOMPSAT-5 occultation data. The scientific data of KOMPSAT-5 will be released to the public. KASI plans to release raw data and processed data. KASI is developing KROPS (KASI Radio Occultation Processing System) for processing the GPS radio occultation data and generating atmospheric profiles. Figure 9 describes the external interface of KROPS. In Fig. 9, K5 MCE is the KOMPSAT-5 Mission Control Element, which receives the occultation and POD...

Earth

Fig. 1 Schematic drawing of the occultation geometry. The various quantities are discussed in the main text where f is the angle between the ray direction and the radius vector r (Fig. 1) and n is the refractive index. Since the GPS and LEO satellites are located outside of the atmosphere where n 1 (here we neglect the ionosphere), it follows that p rG sin fG rL sin fL, which equals the leveling distance between the ray and the Earth's curvature center. When considering an atmosphere with...

Constraining the Abel Bending Angle Integral

In the middle atmosphere where water concentrations are low, radio occultations profile temperature, pressure, and density by determining density versus altitude and combining that with a boundary condition on the hydrostatic integral. Density is derived from refractivity which is derived from bending angle derived in turn from the atmospheric Doppler shift. Maximizing the upper altitude of the bending angle profile requires minimizing errors in the atmospheric Doppler profile. Minimization is...

The ROSA Receiver

The ASI is very active in the field of GPS Radio Occultation (hereafter GPS RO) since several years. The milestones of such developments were the manufacturing of a LAGRANGE GPS receiver devoted to LEO-POD and navigation applications flown onboard the Argentinian SAC-C mission, the development and the manufacturing of the proto flight model receiver ROSA and, finally, the accommodation of ROSA on OCEANSAT-2. The ROSA development is currently carried out by THALES-Alenia. In Fig. 1 the receiver...

Polar Regions

A polar climatology of stratospheric gravity wave activity was assembled by Hei et al. (2008) using CHAMP data between 2001 and 2005. In the Arctic region, Ep showed an annual variation with a maximum in winter, which is consistent with stronger zonal mean horizontal wind speeds and larger Eliassen-Palm flux Fz. Larger values of Fz indicate higher planetary wave activity which can distort the polar night jet. Gravity waves can then be emitted as the jet re-aligns through geostrophic adjustment....

HadAT2 Radiosonde Data

HadAT2 temperatures are provided as monthly anomalies with respect to the monthly 1966-1995 climatology from the year 1958 to present (10 longitude by 5 latitude grid on nine pressure levels). A detailed description of the construction of the HadAT2 data set was given by Coleman and Thorne (2005) and by Thorne Table 1 Characteristics of the original data sets including information on version and horizontal resolution as well as available time period and basic sampling (Steiner et al. 2007)...

Assimilation of Radio Occultation Data in the Global Meteorological Model GME of the German Weather Service

Abstract The assimilation of GPS radio occultations within the three-dimensional variational data assimilation system of the German Weather Service requires GPS radio occultation bending angle forward operators. To optimize the forward operator setup, different one- and three-dimensional bending angle forward operators are evaluated. The innovation statistics for radio occultation data from the CHAMP, GRACE-A, and FORMOSAT-3 COSMIC satellites are compared with estimates based on the background-...

IGOR Receiver and GPS Antennas

The Integrated GPS and Occultation Receiver (IGOR) is manufactured by Broad Reach Engineering and is based on the heritage of the JPL (Jet Propulsion Laboratory) Black Jack receiver. Since KOMPSAT-5 uses 1553B bus as a main interface, the KOMPSAT-5 IGOR has been modified to include a 1553B interface. An internal solid state recorder (SSR) was added in the IGOR for storing receiver output data during the mission. Since KOMPSAT-5 carries a SAR device, IGOR uses four external filters between each...

An Approach for Retrievals in the Presence of Inhomogeneous Liquid Water Clouds

We have developed a new conceptual approach for isolating and removing the effects of inhomogeneous liquid water clouds that are potentially a limiting error source for ATOMMS. Previous approaches such as Kursinski et al. (2004a) have assumed that liquid water is distributed spherically symmetrically, clearly a poor approximation given the clumpy and inhomogeneous distribution of clouds. Our approach is conceptually analogous to the method of isolating and removing ice clouds described in...

Determining the Wet Refractive Index Structure Parameter C2nw

The relation between the refractivity of air at radio frequencies and atmospheric variables is given in Eq. (1) from Ruieger (2002) where N is total atmospheric refrac-tivity, Nd and Nw, respectively the first term and the second term (which is within the brackets) in Eq. (1), are the contributions of the dry gas and water vapor components of the atmosphere, Pd is dry partial pressure in hPa, T is temperature in K, e is partial pressure of water vapor in hPa, and the constants are those of the...

Sampling of the Diurnal Tide of Temperature Using Formosat3Cosmic Data

Borsche, and G. Kirchengast Abstact The Formosat-3 COSMIC satellite constellation, performing radio occultation measurements, allows for an adequate measurement density in space and time to determine the temperature diurnal tide typical for one month, i.e., on a monthly basis. In this initial study on the topic we investigated the diurnal amplitude and phase between 4 km and 35 km altitude in different geographical regions in July 2007. The tropical diurnal tide...

Validation of GOMOSEnvisat High Resolution Temperature Profiles HRTP Using Spectral Analysis

Dalaudier, A. Hauchecorne, and the GOMOS Team Abstract The GOMOS Global Ozone Monitoring by Occultation of Stars instrument on board the Envisat satellite is equipped with two fast photometers operating at 1 kHz sampling frequency in blue and red wavelengths. The bi-chromatic scintillations recorded by the photometers allow the determination of refractive angle, which is proportional to the time delay between the photometer signals. The high resolution density and...

Radio Occultation Soundings in Ionosphere and Space Weather Applications Achievements and Prospects

German Space Weather Application Centre

Abstract It is well known that the GNSS Global Navigation Satellite System signals are affected by the dispersive ionosphere, when the signals pass through it on their way from the transmitter to the receiver. The impact of the ionosphere is an error source that is usually eliminated in the ground based GNSS navigation applications and in the retrieval of the characteristics of the neutral atmosphere from the RO Radio Occultation soundings. However, both RO soundings and ground based GNSS...