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

Xu, Guochang; Yue, Xinan; Zhang, Wengang; Xia, Wan

doi:10.3390/atmos8110208

Cited by 8 publications

(7 citation statements)

References 65 publications

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“…Table 2 presents the GNSS RO missions with their date (life span timeline), purpose, status, country, altitude and inclination angle. Atmospheric profiles produced from Radio occultation compensate for the insufficient active radiosonde soundings with high spatial and temporal distribution and performance on weather research (G. Xu et al, 2017a). Here in Africa, climate change poses a significant threat to economic, social and environmental development in Africa.…”

Section: Gnss Radio Occultationmentioning

confidence: 99%

“…The spatial distribution of radiosondes is very low and inhomogeneous over the African continent. GNSS RO provides atmospheric information (temperature, pressure and humidity profiles) with a high vertical resolution in all-weather conditions which in turn compensates for the shortcomings of the radiosondes data availability in polar regions, deserts and oceans (G. Xu et al, 2017a).…”

Section: Status Of the Ground-based Gnss Network And Radiosonde Stati...mentioning

confidence: 99%

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Validation of the Accuracy of the GNSS RO Temperature Data for Climate Monitoring over Africa

Sa’i,

Musa,

Aleem

et al. 2024

Preprint

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Africa is facing significant impacts from temperature and climate change, with a pronounced warming trend surpassing the global average over the past century. This trend is reshaping climates and ecosystems, leading to increased temperatures, more frequent heatwaves, and altered precipitation patterns across different regions. Severe weather events like droughts, cyclones, and floods pose risks to human lives and well-being. The decline in radiosonde stations across Africa and the lack of collocated meteorological sensors at a majority of GNSS ground-based stations present substantial hurdles in effectively monitoring and responding to climate change in the region. This study thus evaluates the validity of temperature data based on the GNSS Radio Occultation (RO) technique as an alternative to the in-situ radiosonde observations for climate change monitoring over Africa. Three datasets which include GNSS RO, Radiosonde, and ERA5, were analyzed using Python programming, focusing on temperature as the key variable. The validation process involved the use of ten (10) different performance metrics for assessing temperature data from the datasets, including NRMSE (%), Bias (mm), SDR, MAE, ACC, VC, MEF, RI, -squared, and SD Residuals (mm). Most of these metrics exhibited improved performance when dealing with a temperature discrepancy of approximately 1K, although a few stations showed weak or no correlation with certain metrics. Some stations displayed temperature differences as high as 7K due to the number of Radio Occultation Events (ROE) around the stations or problematic Radiosonde data, while most stations exhibited temperature variances of around 1K. These findings suggest that the GNSS RO technique could be considered for Africa due to the current status of the Radiosonde stations over the region.

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Section: Gnss Radio Occultationmentioning

confidence: 99%

Section: Status Of the Ground-based Gnss Network And Radiosonde Stati...mentioning

confidence: 99%

Validation of the Accuracy of the GNSS RO Temperature Data for Climate Monitoring over Africa

Sa’i,

Musa,

Aleem

et al. 2024

Preprint

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“…WetPrf products are interpolated onto 100 m vertical resolution from 0.1 to 40 km based on the one-dimensional variational method (Kursinski et al, 2000;Wee and Kuo, 2015). According to Xu et al (2017) biases could exist for altitudes below ∼ 5-8 km in the wetPrf. We use the reprocessed and post-processed RO data, which are stable and accurate observations for climate studies.…”

Section: Gnss Ro Temperature Datamentioning

confidence: 99%

The semi-annual oscillation (SAO) in the upper troposphere and lower stratosphere (UTLS)

Shangguan

Wang

2022

Atmos. Chem. Phys.

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Abstract. Both the scientific and operational communities are increasingly interested in subseasonal to seasonal variations of weather and climate. The semi-annual oscillation (SAO) has been studied extensively at the surface as well as in the middle atmosphere (upper stratosphere and the lower mesosphere). However, the SAO in the upper troposphere and lower stratosphere (UTLS) has been less discussed. Here we find evident SAO of temperature in the UTLS (250–175 hPa) from the subtropics to middle latitudes (22.5–42.5∘) using high-quality satellite measurements, reanalysis data, and model simulations. We show the mechanism of its formation by an energy budget analysis. The temperature in the Northern Hemisphere (NH) UTLS shows the first peak in February according to the dynamical heating and shows the second peak in July due to the dynamical heating and moist processes. Similar to the NH, the austral winter time maximum temperature in the Southern Hemisphere (SH) is related to dynamical heating and the austral summer time maximum is related to both moisture and dynamical heating in the UTLS. Model simulations indicate that the SAO in the UTLS is partly affected by the existence of an SAO in sea surface temperatures (SSTs) in the SH mid-latitudes and weakly affected by the SAO in SSTs in the NH mid-latitudes.

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“…In order to measure climate change accurately, the long-term, global and stable observations of the vertical composition of atmospheric temperature (vertical profile) trends are very much essential [1] . However, it is not an easy task to construct a consistent temperature record using measurements from different instruments where the characteristics of the instrument may be changed due to its changing environment.…”

Section: Introductionmentioning

confidence: 99%

“…Being an active sensor, the GPS RO measurements are not contaminated by persistent clouds, precipitation, and underlying surface conditions, and therefore, are ideally suited for atmospheric climate temperature trend detection [22][23] . By using 49 months of high precision GPS RO data from CHAMP, Ho et al [1] were able to characterize the differences of the monthly mean AMSU/MSU temperatures of the lower stratosphere (TLS) between the Remote Sensing Systems (RSS) Inc. [24] and University of Alabama in Huntsville (UAH) [25] groups where different data merging procedures and different satellite measurements are used as references. However, because CHAMP has only one GPS receiver, it takes more than three months to complete full diurnal coverage once over a region in the low and middle latitudes.…”

Section: Introductionmentioning

confidence: 99%

(Online First)A study of temperature profiles and trends as revealed by COSMIC RO technique and balloon –borne radiosonde instrument

Kumar¹,

Rao

Kumar

et al. 2018

som

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This research presents atmospheric temperature profiles and trends retrieved using COSMIC RO technique and balloon-borne radiosonde instrument in 2007 and a few cases during 2017. By effectively using ‘wet’ temperature product available at COSMIC Data Analysis and Archive Center (CDAAC) website, an analysis has been made to present temperature profiles and trends at various regions including, Indian, Taiwan and Japan. A one-to-one correspondence is, clearly, seen between temperature profiles retrieved with COSMIC RO and radiosonde instrument. But, few and dominant differences in temperature profiles are found below at an altitude of ~5 km and above around tropopause (~16-17 km). The dominant differences found at below ~5km could be due to the inhomogeneous distribution of humidity present, generally, at the tropical regions, whereas above the tropopause altitudes, differences might be due to the ionospheric residual correction as reported by other researchers. Further, temperature monthly trends at various regions show distinct characteristics including, a sharp temperature inversion up to tropopause altitude. In addition, it is also observed maximum temperatures (peaks) during the northern summer seasons (May, June, July, and August) and minimum temperatures (troughs) during the northern winter seasons (November, December, January, and February) near to the surface of the Earth. Interestingly, although it is generally observed that the tropopause altitude is located at ~ 16-17 km at various regions, a keen observation reveals that distinct seasonal and latitudinal variations can be witnessed. With this case study, it may be concluded that the COSMIC RO technique is able to provide very accurate measurement, which reiterates its importance as a powerful tool to explore the Earth’s atmosphere on the local and global scale.

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

Cited by 8 publications

References 65 publications

Validation of the Accuracy of the GNSS RO Temperature Data for Climate Monitoring over Africa

Validation of the Accuracy of the GNSS RO Temperature Data for Climate Monitoring over Africa

The semi-annual oscillation (SAO) in the upper troposphere and lower stratosphere (UTLS)

(Online First)A study of temperature profiles and trends as revealed by COSMIC RO technique and balloon –borne radiosonde instrument

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