orrecting negatively-biased refractivity below ducts in GNSS radio occultation: An optimal estimation approach towards improving planetary boundary layer (PBL) characterization

2017 ◽  
Author(s):  
Anonymous
Keyword(s):  
Boundary Layer ◽  
Planetary Boundary Layer ◽  
Radio Occultation ◽  
Optimal Estimation

scholarly journals Correcting negatively biased refractivity below ducts in GNSS radio occultation: an optimal estimation approach towards improving planetary boundary layer (PBL) characterization

2017 ◽  
Vol 10 (12) ◽  
pp. 4761-4776 ◽  
Author(s):  
Kuo-Nung Wang ◽  
Manuel de la Torre Juárez ◽  
Chi O. Ao ◽  
Feiqin Xie
Keyword(s):  
Boundary Layer ◽  
Planetary Boundary Layer ◽  
Radio Occultation ◽  
Microwave Radiometer ◽  
Linear Structure ◽  
Optimal Estimation ◽  
Precipitable Water ◽  
Satellite Observation ◽  
Reconstruction Method ◽  
Negative Bias

Abstract. Global Navigation Satellite System (GNSS) radio occultation (RO) measurements are promising in sensing the vertical structure of the Earth's planetary boundary layer (PBL). However, large refractivity changes near the top of PBL can cause ducting and lead to a negative bias in the retrieved refractivity within the PBL (below ∼ 2 km). To remove the bias, a reconstruction method with assumption of linear structure inside the ducting layer models has been proposed by Xie et al. (2006). While the negative bias can be reduced drastically as demonstrated in the simulation, the lack of high-quality surface refractivity constraint makes its application to real RO data difficult. In this paper, we use the widely available precipitable water (PW) satellite observation as the external constraint for the bias correction. A new framework is proposed to incorporate optimization into the RO reconstruction retrievals in the presence of ducting conditions. The new method uses optimal estimation to select the best refractivity solution whose PW and PBL height best match the externally retrieved PW and the known a priori states, respectively. The near-coincident PW retrievals from AMSR-E microwave radiometer instruments are used as an external observational constraint. This new reconstruction method is tested on both the simulated GNSS-RO profiles and the actual GNSS-RO data. Our results show that the proposed method can greatly reduce the negative refractivity bias when compared to the traditional Abel inversion.

scholarly journals Correcting negatively-biased refractivity below ducts in GNSS radio occultation: An optimal estimation approach towards improving planetary boundary layer (PBL) characterization

2017 ◽  
Author(s):  
Kuo-Nung Wang ◽  
Manuel de la Torre Juarez ◽  
Chi O. Ao ◽  
Feiqin Xie
Keyword(s):  
Boundary Layer ◽  
Planetary Boundary Layer ◽  
Radio Occultation ◽  
Microwave Radiometer ◽  
Linear Structure ◽  
Optimal Estimation ◽  
Precipitable Water ◽  
Satellite Observation ◽  
Reconstruction Method ◽  
Negative Bias

Abstract. GNSS radio occultation (RO) measurements are promising in sensing the vertical structure of the Earth’s planetary boundary layer (PBL). However, large refractivity changes near the top of PBL can cause ducting and lead to a negative bias in the retrieved refractivity within the PBL (below ~ 2 km). To remove the bias, a reconstruction method with assumption of linear structure inside the ducting layer models has been proposed by Xie et al. (2006). While the negative bias can be reduced drastically as demonstrated in the simulation, the lack of high-quality surface refractivity constraint makes its application to real RO data difficult. In this paper, we use the widely available precipitable water (PW) satellite observation as the external constraint for the bias correction. A new framework is proposed to incorporate optimization into the RO reconstruction retrievals in the presence of ducting condition. The new method uses optimal estimation to select the best refractivity solution whose precipitable water (PW) and PBL height best match the external PW measurements and the known a-priori, respectively. The near coincident PW measurements from AMSR-E microwave radiometer instruments are used as an external observational constraint. This new reconstruction method is tested on both the simulated GNSS-RO profiles and the actual GNSS-RO data. Our results show that the proposed method can greatly reduce the negative refractivity bias when compared to traditional Abel inversion.

scholarly journals Planetary boundary layer heights from GPS radio occultation refractivity and humidity profiles

2012 ◽  
Vol 117 (D16) ◽  
pp. n/a-n/a ◽  
Author(s):  
Chi O. Ao ◽  
Duane E. Waliser ◽  
Steven K. Chan ◽  
Jui-Lin Li ◽  
Baijun Tian ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Planetary Boundary Layer ◽  
Radio Occultation ◽  
Gps Radio Occultation ◽  
Humidity Profiles

scholarly journals Diurnal Variation of the Planetary Boundary Layer Height Observed from GNSS Radio Occultation and Radiosonde Soundings over the Southern Great Plains

2021 ◽  
Author(s):  
Kevin J. Nelson ◽  
Feiqin Xie ◽  
Chi O. Ao ◽  
Mayra I. Oyola-Merced
Keyword(s):  
Boundary Layer ◽  
Planetary Boundary Layer ◽  
Great Plains ◽  
Seasonal Changes ◽  
Radio Occultation ◽  
Climate Model ◽  
Spatial And Temporal Variation ◽  
Cosmic Radio ◽  
Southern Great Plains ◽  
Geographical Regions

AbstractThe planetary boundary layer (PBL) height (PBLH) is a key physical parameter of the PBL affected by numerous physical processes within the boundary layer. Specifically, the PBLH over land exhibits large spatial and temporal variation across different geographical regions. In this study, the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) radio occultation (RO) and high- resolution radiosonde profiles from 2007 to 2013 were analyzed to estimate the diurnal cycle of the PBLH over the Southern Great Plains (SGP) in the US. Large variations in PBLH derived from radiosonde temperature, moisture, and refractivity are observed on seasonal scales. COSMIC RO is capable of observing diurnal and seasonal variations in the terrestrial PBLH over the SGP region. Annual mean diurnal amplitude of approximately 250 m in the terrestrial PBLH was observed, with maxima occurring at around 15:00 (LST, Local Solar Time) in both the co-located radiosondes and COSMIC RO profiles. Seasonal changes in the PBLH diurnal cycles ranging from approximately 100 m to 400 m were also observed. Such PBL diurnal and seasonal changes can be further incorporated into PBL parameterizations to help improve weather and climate model prediction.

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