An investigation of atmospheric temperature profiles in the Australian region using collocated GPS radio occultation and radiosonde data

Zhang, K.; Fu, Erjiang; Silcock, D.; Wang, Yan; Kuleshov, Yuriy

doi:10.5194/amt-4-2087-2011

Cited by 44 publications

(27 citation statements)

References 17 publications

(15 reference statements)

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“…Note that the sample selection and data-matching method may impact the results of comparison between COSMIC and radiosonde measurements. Table 1 presents the mean temperature bias and standard deviation (RMSE) between COSMIC and radiosonde data reported in some previous studies [4,51,66,67]. Regional differences are found in temperature bias and RMSE.…”

Section: Discussionmentioning

confidence: 99%

Assessment of Atmospheric Wet Profiles Obtained from COSMIC Radio Occultation Observations over China

Yue

Zhang

et al. 2017

Atmosphere

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Atmosperic profiles derived from Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) radio occultation (RO) measurements make up for the lack of operational radiosonde soundings with a high spatiotemporal distribution, and their performance over China is assessed in this paper. COSMIC-retrieved atmospheric wet profiles from 2014 to 2015 are compared to the contemporaneous radiosonde profiles from 120 stations, and the vertical mean differences are used. The results show that the vertical mean biases of temperature, pressure and vapor pressure are −0.10 K, 0.69 hPa and −0.01 hPa, respectively, and that for refractivity is 0.17 N. Moreover, the temperature differences are positively correlated with station altitude, yet both the pressure and vapor pressure differences are negatively correlated with station latitude, as is the refractivity difference. The large temperature difference arising from the Qinghai-Tibet Plateau (QTP) region may be associated with the complex topography of the area and the limitations in the background model used in the COSMIC profile retrieval. Furthermore, negative refractivity bias between COSMIC and radiosonde data occurs below 5 km and is large in wet southern China, with a value of less than 1%. This result may be related to more humid conditions and super-refraction.

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Section: Discussionmentioning

confidence: 99%

Assessment of Atmospheric Wet Profiles Obtained from COSMIC Radio Occultation Observations over China

Yue

Zhang

et al. 2017

Atmosphere

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“…Vertical profiles have high accuracy for temperature (< 1 K from 5 to 25 km) and spatial resolution varying from 100 m at the surface to 1.5 km at 35 km altitude (1 km at the altitude of tropopause) (Pirscher et al, 2010;Anthes, 2011). Collocation mismatch affects the comparison: standard deviation errors are < 0.5 K for temperature in both the troposphere (850-200 hPa) and the stratosphere, and for relative humidity they are < 3.5% for 3 h temporal buffer and 100 km spatial buffer (Sun et al, 2010;Zhang et al, 2011). GPS RO data observed by lowEarth-orbit satellites have been used previously for GWs observations in the LS (Tsuda et al, 2000;Liou et al, 2003Liou et al, , 2006.…”

Section: Methodsmentioning

confidence: 99%

Observation and a numerical study of gravity waves during tropical cyclone Ivan (2008)

et al. 2014

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Abstract. Gravity waves (GWs) with horizontal wavelengths of 32-2000 km are investigated during tropical cyclone (TC) Ivan (2008) in the southwest Indian Ocean in the upper troposphere (UT) and the lower stratosphere (LS) using observational data sets, radiosonde and GPS radio occultation data, ECMWF analyses and simulations of the French numerical model Meso-NH with vertical resolution < 150 m near the surface and 500 m in the UT/LS. Observations reveal dominant low-frequency GWs with short vertical wavelengths of 0.7-3 km, horizontal wavelengths of 80-400 km and periods of 4.6-13 h in the UT/LS. Continuous wavelet transform and image-processing tools highlight a wide spectrum of GWs with horizontal wavelengths of 40-1800 km, short vertical wavelengths of 0.6-3.3 km and periods of 20 min-2 days from modelling analyses. Both ECMWF and Meso-NH analyses are consistent with radiosonde and GPS radio occultation data, showing evidence of a dominant TCrelated quasi-inertia GW propagating eastward east of TC Ivan with horizontal and vertical wavelengths of 400-800 km and 2-3 km respectively in the LS, more intense during TC intensification. In addition, the Meso-NH model produces a realistic, detailed description of TC dynamics, some highfrequency GWs near the TC eye, variability of the tropospheric and stratospheric background wind and TC rainband characteristics at different stages of TC Ivan. A wave number 1 vortex Rossby wave is suggested as a source of dominant inertia GW with horizontal wavelengths of 400-800 km, while shorter scale modes (100-200 km) located at northeast and southeast of the TC could be attributed to strong localized convection in spiral bands resulting from wave number 2 vortex Rossby waves. Meso-NH simulations also reveal GWrelated clouds east of TC Ivan.

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“…Recently, the GNSS (global navigation satellite system)-based radio occultation (RO) technique has shown great capability in detecting the global E s occurrence by using high-resolution signal-to-noise ratio (SNR) data (Arras et al, 2008;Chu et al, 2014;Hocke et al, 2001;Wu et al, 2005;Yeh et al, 2012;Zeng and Sokolovskiy, 2010). GNSS RO technique has proven to be a powerful tool in monitoring climate, weather, and space weather (Anthes, 2011;Foelsche et al, 2011;Liu et al, 2010;Schreiner et al, 2007;Zhang et al, 2011;Yue et al, 2012). After the pioneer GPS/MET (Global Positioning System/Meteorology) mission, many low-Earth-orbit (LEO) satellites were launched with a RO payload, including CHAMP (Challenging Minisatellite Payload), GRACE (Gravity Recovery And Climate Experiment), SAC-C/D (Scientific Application Satellite-C/D), COSMIC (Constellation Observing System for Meteorology, Ionosphere, and Climate), C/NOFS (Communications/Navigation Outage Forecasting System), Metop-A/B (Meteorological Operational Satellite Program of Europe -A/B), and TerraSAR-X (X-band Terra SAR)/TanDEM-X (TerraSAR-X add-on for Digital Elevation Measurements).…”

Section: Introductionmentioning

confidence: 99%

Case study on complex sporadic E layers observed by GPS radio occultations

et al. 2015

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Abstract. The occurrence of sporadic E (E s ) layers has been a hot scientific topic for a long time. The GNSS (global navigation satellite system)-based radio occultation (RO) has proven to be a powerful technique for detecting the global E s layers. In this paper, we focus on some cases of complex E s layers based on the RO data from multiple missions processed in UCAR/CDAAC (University Corporation for Atmospheric Research (UCAR) the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) Data Analysis and Archive Center (CDAAC)). We first show some examples of multiple E s layers occurred in one RO event. Based on the evaluations between colocated simultaneous RO events and between RO and lidar observations, it could be concluded that some of these do manifest the multiple E s layer structures. We then show a case of the occurrence of E s in a broad region during a certain time interval. The result is then validated by independent ionosondes observations. It is possible to explain these complex E s structures using the popular wind shear theory. We could map the global E s occurrence routinely in the near future, given that more RO data will be available. Further statistical studies will enhance our understanding of the E s mechanism. The understanding of E s should benefit both E s -based long-distance communication and accurate neutral RO retrievals.

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An investigation of atmospheric temperature profiles in the Australian region using collocated GPS radio occultation and radiosonde data

Cited by 44 publications

References 17 publications

Assessment of Atmospheric Wet Profiles Obtained from COSMIC Radio Occultation Observations over China

Assessment of Atmospheric Wet Profiles Obtained from COSMIC Radio Occultation Observations over China

Observation and a numerical study of gravity waves during tropical cyclone Ivan (2008)

Case study on complex sporadic E layers observed by GPS radio occultations

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