The COSMIC/FORMOSAT-3 Mission: Early Results

Anthes, Richard A.; Bernhardt, P. A.; Chen, Y.; Cucurull, Lídia; Dymond, K. F.; Ector, D.; Healy, S. B.; Ho, Shu‐Peng; Hunt, Doug; Kuo, Ying‐Hwa; Liu, H.; Manning, Kevin W.; McCormick, Christopher; Meehan, T. K.; Randel, William J.; Rocken, C.; Schreiner, William S.; Sokolovskiy, Sergey; Syndergaard, Stig; Thompson, D. C.; Trenberth, Kevin E.; Wee, Tae-Kwon; Yen, Nick; Zeng, Zhen

doi:10.1175/bams-89-3-313

Cited by 854 publications

(782 citation statements)

References 38 publications

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“…The GPSRO technique has unique features of high accuracy, precision, high vertical resolution, and no contamination from clouds, no requirement for system calibration, and no instrument drift (Anthes et al, 2008;Kursinski, Hajj, Hardy, Schofield, & Linfield, 1997). The GPSRO satellites receive radio signals passing through Earth's atmosphere from GPS satellites and calculate the bending angle from the phase during occultation events.…”

Section: Datamentioning

confidence: 99%

Vertical and latitudinal variation of the intertropical convergence zone derived using GPS radio occultation measurements

Basha¹,

Kishore²,

Ratnam

et al. 2015

Remote Sensing of Environment

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Using GPS radio occultation refractivity data collected over the period of 2002-2013, we present a new method for identification of the intertropical convergence zone (ITCZ). The ITCZ is identified by estimating the maximum in the monthly meridional refractivity and specific humidity field by applying a Gaussian fit at each longitude. The interannual variability and climatology of the ITCZ is presented from 12 years of refractivity data. This new method captures all the general features of ITCZ extent and its variability. We also examine the effects of the ITCZ vertically during different seasons. The ITCZ is observed mostly at eastern Pacific in May month, and it is zonally distributed in the September and October months of each year. The zonal variability is large between lower and higher levels, particularly over the Indian monsoon and western Pacific. The latitudinal difference in the vertical extent between 850 hPa and higher levels is larger during the northern hemisphere (NH) summer than NH winter.

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Section: Datamentioning

confidence: 99%

Vertical and latitudinal variation of the intertropical convergence zone derived using GPS radio occultation measurements

Basha¹,

Kishore²,

Ratnam

et al. 2015

Remote Sensing of Environment

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“…The GPS-slant-path water vapor measurements are most effective at the mid to upper levels where slant paths intersect (Liu and Xue, 2006). At the same time, the low-orbiting-satellite-based GPS occultation data generally do not reach the surface and have poor horizontal resolution (Ware et al, 1996;Anthes et al, 2008). Mesoscale surface observational networks (e.g., Brock et al, 1995) are currently the best platform for near-surface moisture observations, but their spatial resolution may not be sufficient to resolve fine-scale structures important for convective initiation (Weckwerth et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

Two-dimensional variational analysis of near-surface moisture from simulated radar refractivity-related phase change observations

et al. 2013

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Because they are most sensitive to atmospheric moisture content, radar refractivity observations can provide high-resolution information about the highly variable low-level moisture field. In this study, simulated radar refractivity-related phase-change data were created using a radar simulator from realistic highresolution model simulation data for a dryline case. These data were analyzed using the 2DVAR system developed specifically for the phase-change data.Two sets of experiments with the simulated observations were performed, one assuming a uniform target spacing of 250 m and one assuming nonuniform spacing between 250 m to 4 km. Several sources of observation error were considered, and their impacts were examined. They included errors due to ground target position uncertainty, typical random errors associated with radar measurements, and gross error due to phase wrapping. Without any additional information, the 2DVAR system was incapable of dealing with phase-wrapped data directly. When there was no phase wrapping in the data, the 2DVAR produced excellent analyses, even in the presence of both position uncertainty and random radar measurement errors. When a separate pre-processing step was applied to unwrap the phase-wrapped data, quality moisture analyses were again obtained, although the analyses were smoother due to the reduced effective resolution of the observations by interpolation and smoothing involved in the unwrapping procedure. The unwrapping procedure was effective even when significant differences existed between the analyzed state and the state at a reference time. The results affirm the promise of using radar refractivity phase-change measurements for near-surface moisture analysis.

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“…As described by Kirchengast and Schweitzer (2011), the LMIO method can be considered as a next generation of the well established and successful GNSS-LEO radio occultation (GRO) method (Ware et al, 1996;Kursinski et al, 1997;Steiner et al, 2001;Anthes et al, 2008;Luntama et al, 2008;Steiner et al, 2009;Ho et al, 2009). LMIO and GRO share the occultation measurement principle (Phinney and Anderson, 1968; and the use of highly coherent and stable inter-satellite signals, and therefore the potential of providing accurate, long-term, consistent benchmark data with high vertical resolution and global coverage.…”

mentioning

confidence: 99%

Greenhouse gas profiling by infrared-laser and microwave occultation: retrieval algorithm and demonstration results from end-to-end simulations

2011

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Abstract. Measuring greenhouse gas (GHG) profiles with global coverage and high accuracy and vertical resolution in the upper troposphere and lower stratosphere (UTLS) is key for improved monitoring of GHG concentrations in the free atmosphere. In this respect a new satellite mission concept adding an infrared-laser part to the already well studied microwave occultation technique exploits the joint propagation of infrared-laser and microwave signals between Low Earth Orbit (LEO) satellites. This synergetic combination, referred to as LEO-LEO microwave and infrared-laser occultation (LMIO) method, enables to retrieve thermodynamic profiles (pressure, temperature, humidity) and accurate altitude levels from the microwave signals and GHG profiles from the simultaneously measured infrared-laser signals. However, due to the novelty of the LMIO method, a retrieval algorithm for GHG profiling is not yet available. Here we introduce such an algorithm for retrieving GHGs from LEO-LEO infraredlaser occultation (LIO) data, applied as a second step after retrieving thermodynamic profiles from LEO-LEO microwave occultation (LMO) data. We thoroughly describe the LIO retrieval algorithm and unveil the synergy with the LMOretrieved pressure, temperature, and altitude information. We furthermore demonstrate the effective independence of the GHG retrieval results from background (a priori) information in discussing demonstration results from LMIO end-toend simulations for a representative set of GHG profiles, including carbon dioxide (CO 2 ), water vapor (H 2 O), methane (CH 4 ), and ozone (O 3 ). The GHGs except for ozone are well Correspondence to: V. Proschek (veronika.proschek@uni-graz.at) retrieved throughout the UTLS, while ozone is well retrieved from about 10 km to 15 km upwards, since the ozone layer resides in the lower stratosphere. The GHG retrieval errors are generally smaller than 1 % to 3 % r.m.s., at a vertical resolution of about 1 km. The retrieved profiles also appear unbiased, which points to the climate benchmarking capability of the LMIO method. This performance, found here for clear-air atmospheric conditions, is unprecedented for vertical profiling of GHGs in the free atmosphere and encouraging for future LMIO implementation. Subsequent work will examine GHG retrievals in cloudy air, addressing retrieval performance when scanning through intermittent upper tropospheric cloudiness.

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The COSMIC/FORMOSAT-3 Mission: Early Results

Abstract: The COSMIC radio occultation mission represents a revolution in atmospheric sounding from space, with precise, accurate, and all-weather global observations useful for weather, climate, and space weather research and operations. GPS Signal GPS Satellite

Cited by 854 publications

References 38 publications

Vertical and latitudinal variation of the intertropical convergence zone derived using GPS radio occultation measurements

Vertical and latitudinal variation of the intertropical convergence zone derived using GPS radio occultation measurements

Two-dimensional variational analysis of near-surface moisture from simulated radar refractivity-related phase change observations

Greenhouse gas profiling by infrared-laser and microwave occultation: retrieval algorithm and demonstration results from end-to-end simulations

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