Applications of COSMIC to Meteorology and Climate

Anthes, Richard A.; Rocken, Christian; Kuo, Ying‐Hwa

doi:10.3319/tao.2000.11.1.115(cosmic)

Cited by 178 publications

(112 citation statements)

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“…It is envisaged that future system upgrades will include assimilation of data from the COSMIC constellation of satellites (Anthes et al, 2000), and later from the global navigation satellite system receiver for atmospheric sounding (GRAS) instrument on board the METOP satellite (Loiselet et al, 2000). As a result of this increase in the quantity of GPSRO data for assimilation, together with increased timeliness, we…”

Section: Discussionmentioning

confidence: 99%

Operational NWP assimilation of GPS radio occultation data

Buontempo

Jupp

Rennie

2008

Atmospheric Science Letters

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Since 26 September 2006, refractivity profiles from the CHAMP and GRACE-A satellites have been assimilated in the Met Office operational global numerical weather prediction system. This article presents the results of two experiments, which aim to determine the potential impact on the forecast resulting from the assimilation of this new dataset, and goes on to describe the Met Office operational implementation. Despite the limited number of occultations available for assimilation, the experiments show a significant positive impact on upper troposphere and lower stratosphere temperature and geopotential height fields, mid-tropospheric geopotential heights and pressure at mean sea level in the Southern Hemisphere.  Crown

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Section: Discussionmentioning

confidence: 99%

Operational NWP assimilation of GPS radio occultation data

Buontempo

Jupp

Rennie

2008

Atmospheric Science Letters

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“…The COSMIC/FORMOSAT-3 constellation (Anthes et al, 2000) of global positioning system (GPS) receivers was launched into orbit on 15 April 2006, and they have provided GPS radio occultation (GPSRO) measurements for the general scientific community since 28 July 2006. The measurements have applications in operational numerical weather prediction (NWP), climate/reanalysis studies and ionospheric physics.…”

Section: Introductionmentioning

confidence: 99%

Forecast impact experiment with a constellation of GPS radio occultation receivers

Healy

2008

Atmospheric Science Letters

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A forecast impact experiment with a constellation of global positioning system radio occultation (GPSRO) receivers is presented. The constellation includes the six COSMIC/FORMO-SAT-3 satellites, combined with the GRACE-A and CHAMP satellites. It is shown that rising and setting occultations measured with the COSMIC satellites have similar bending angle error characteristics. The GPSRO measurements improve the root mean square (rms) geopotential height forecast errors at 500, 200, and 100 hPa in both the Northern and Southern Hemispheres. The forecast fit to radiosonde temperature measurements in the Stratosphere is also improved.

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“…The assimilation of retrieved local refractivity can improve model simulations/forecasts when the numerical model resolution is relatively coarse (@300 km; Anthes et al 2000). This approach is also proven to have a positive impact on reducing analysis and forecast temperature error in the upper troposphere and lower stratosphere with a higher model resolution (@60 km; Healy et al 2005).…”

Section: Experiments 3: Sensitivity Test Of Modelmentioning

confidence: 99%

Error Characteristics of GPS Retrieved Refractivity Using a Simulation Study

Chen

Vandenberghe

Huang

2006

Journal of the Meteorological Society of Japan

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A simulation study was designed to investigate the error characteristics of retrieved local refractivity arising only from the assumption of spherical symmetry. The convergence of error estimation with respect to different horizontal resolutions was examined, and a resolution higher than 30 km was found to be reasonable for this simulation study.Two cases, one in summer 1997 and the other in winter 1998, were used to study errors of retrieved local refractivity. The error can reach 10 units in the lower troposphere under the assumption of spherical symmetry. Error decreases with height linearly, until about 3 km and then dramatically above 3 km. A local maximum error occurs at approximately 6 km in the 1997 case because there were large refractivity disturbances on the lee side of the Rocky Mountains around that level.The level of the maximum error over land (@2-3 km) was higher than over ocean (@1 km) due to complex topography, as well as a deeper boundary layer over land. As a result, the average root mean square error below 3 km presents a meandering feature over the entire domain of interest. Moreover, the error close to the surface over ocean was slightly higher than that over land. However, in the 2-4 km range the error was slightly lower over ocean than over land. Note that the altitude of maximum error over ocean can be shifted upward when strong disturbances, such as severe weather, exist over the region. The error during summer was larger than that during winter, and it was greater at lower latitudes than at higher latitudes, as reported in previous studies.When modeling retrieved local refractivity, the observational error is a function of the model horizontal resolution. The error was reduced as model resolution was decreased, but there was a lower limit for an optimal resolution. This optimal resolution in the lower atmosphere was higher (@190 km) than that in the middle and upper atmosphere (@250 km) in this study, due to a stronger vertical gradient of refractivity and higher vertical resolution in the lower troposphere.

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Applications of COSMIC to Meteorology and Climate

Abstract: The GPS/MET (Global Positioning System/Meteorology, Ware et al. 1996) project demonstrated atmospheric limb sounding from low-earth orbit (LEO) with high vertical resolution, high accuracy, and global cover agein all weather.

Cited by 178 publications

References 60 publications

Operational NWP assimilation of GPS radio occultation data

Operational NWP assimilation of GPS radio occultation data

Forecast impact experiment with a constellation of GPS radio occultation receivers

Error Characteristics of GPS Retrieved Refractivity Using a Simulation Study

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