scholarly journals 1DVAR retrieval method for GPS radio occultation measurements of atmospheric temperature and humidity profiles

2013 ◽  
Vol 62 (15) ◽  
pp. 159301
Author(s):  
Bi Yan-Meng ◽  
Liao Mi ◽  
Zhang Peng ◽  
Ma Gang
Keyword(s):  
Radio Occultation ◽  
Atmospheric Temperature ◽  
Retrieval Method ◽  
Gps Radio Occultation ◽  
Temperature And Humidity ◽  
Humidity Profiles

Optimum prediction of atmospheric temperature using GPS radio occultation measurements

2017 ◽  
Vol 919 (1) ◽  
pp. 48-51
Author(s):  
N.H. Javadov ◽  
R.A. Eminov ◽  
N.Ya. Ismailov
Keyword(s):  
Radio Occultation ◽  
General Procedure ◽  
Atmospheric Temperature ◽  
Mean Value ◽  
Optimization Criterion ◽  
Temperature Measurements ◽  
Gps Radio Occultation ◽  
Applied Optimization ◽  
Quadratic Deviation ◽  
The Mean

The matters of optimum forecasting atmospheric temperature using GPS radio occultation measurements are considered. The analysis of the available data regarding to the comparison of temperature measurements using radio occultation method and radiosondes was made. As a result it was concluded that the mean value of those results’ difference and also the mean quadratic deviation of these difference increases in common by increase of the forecasting time. In order to prevent surplus loading of telemetry channels and broadcasting inaccurate forecast values via them the optimization of general procedure of radio occultation temperature measurements are carried out using fine functions method. For optimization the concurrent parameters, changing on antiphase order are determined. It is found out that utilization of fine function method taking into account the applied optimization criterion and some limitation conditions make it possible to optimize the whole procedure of forecasting atmospheric temperature using the GPS radio occultation measurements.

scholarly journals Correction to “Atmospheric temperature change detection with GPS radio occultation 1995 to 2008”

2010 ◽  
Vol 37 (3) ◽  
pp. n/a-n/a
Author(s):  
A. K. Steiner ◽  
G. Kirchengast ◽  
B. C. Lackner ◽  
B. Pirscher ◽  
M. Borsche ◽  
...  
Keyword(s):  
Change Detection ◽  
Temperature Change ◽  
Radio Occultation ◽  
Atmospheric Temperature ◽  
Gps Radio Occultation

scholarly journals A New Technique for Estimation of Lower-Tropospheric Temperature and Water Vapor Profiles from Radio Occultation Refractivity

2009 ◽  
Vol 26 (6) ◽  
pp. 1075-1089 ◽  
Author(s):  
D. Jagadheesha ◽  
B. Simon ◽  
P-K. Pal ◽  
P. C. Joshi ◽  
A. Maheshwari
Keyword(s):  
Radio Occultation ◽  
Specific Humidity ◽  
New Technique ◽  
Radiosonde Data ◽  
Boreal Summer ◽  
Tropospheric Temperature ◽  
Lower Altitude ◽  
Temperature And Humidity ◽  
The Tropics ◽  
Humidity Profiles

Abstract An empirical technique is proposed to obtain temperature and humidity profiles over the tropics using radio occultation refractivity profiles and surface/available lower-altitude temperature and pressure measurements over humid tropical regions. The technique is tested on a large number of diverse radiosonde-derived refractivity profiles over the tropics (30°S–30°N) and selected Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) radio occultation refractivity profiles that have collocated radiosonde observations over the region 10°S–30°N during the boreal summer of 2006. In a number of cases, the results were in good agreement with the collocated radiosonde data. The error statistics of temperature and humidity profiles obtained from the proposed technique are discussed and compared with the previously published results from another technique and also with the results of a one-dimensional variational data assimilation (1DVAR) technique given with COSMIC data. It is found that the previously published results and proposed technique are marginally better (worse) in reproducing observed relative humidity (specific humidity) when compared to the 1DVAR technique. The proposed new technique is applied on COSMIC refractivity profiles over the Bay of Bengal during summer 2007 to derive changes in vertical thermal and moisture changes in the troposphere between active and break phases of the monsoon pattern and many of the observed features are captured reasonably well.

scholarly journals Measurement of Solar Absolute Brightness Temperature Using a Ground-Based Multichannel Microwave Radiometer

2021 ◽  
Vol 13 (15) ◽  
pp. 2968
Author(s):  
Lianfa Lei ◽  
Zhenhui Wang ◽  
Yingying Ma ◽  
Lei Zhu ◽  
Jiang Qin ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Brightness Temperature ◽  
Microwave Radiation ◽  
Atmospheric Temperature ◽  
Solar Observation ◽  
The Sun ◽  
Temperature And Humidity ◽  
Microwave Radiometers ◽  
Humidity Profiles ◽  
Absolute Brightness

Ground-based multichannel microwave radiometers (GMRs) can observe the atmospheric microwave radiation brightness temperature at K-bands and V-bands and provide atmospheric temperature and humidity profiles with a relatively high temporal resolution. Currently, microwave radiometers are operated in many countries to observe the atmospheric temperature and humidity profiles. However, a theoretical analysis showed that a radiometer can be used to observe solar radiation. In this work, we improved the control algorithm and software of the antenna servo control system of the GMR so that it could track and observe the sun and we use this upgraded GMR to observe solar microwave radiation. During the observation, the GMR accurately tracked the sun and responded to the variation in solar radiation. Furthermore, we studied the feasibility for application of the GMR to measure the absolute brightness temperature (TB) of the sun. The results from the solar observation data at 22.235, 26.235, and 30.000 GHz showed that the GMR could accurately measure the TB of the sun. The derived solar TB measurements were 9950 ± 334, 10,351 ± 370, and 9217 ± 375 K at three frequencies. In a comparison with previous studies, we obtained average percentage deviations of 9.1%, 5.3%, and 4.5% at 22.235, 26.235, and 30.0 GHz, respectively. The results demonstrated that the TB of the sun retrieved from the GMR agreed well with the previous results in the literature. In addition, we also found that the GMR responded to the variation in sunspots and a positive relationship existed between the solar TB and the sunspot number. According to these results, it was demonstrated that the solar observation technique can broaden the field usage of GMR.

scholarly journals A New Algorithm for the Retrieval of Atmospheric Profiles from GNSS Radio Occultation Data in Moist Air and Comparison to 1DVar Retrievals

2019 ◽  
Vol 11 (23) ◽  
pp. 2729 ◽  
Author(s):  
Li ◽  
Kirchengast ◽  
Scherllin-Pirscher ◽  
Schwaerz ◽  
Nielsen ◽  
...  
Keyword(s):  
Radio Occultation ◽  
Optimal Estimation ◽  
Satellite System ◽  
Temporal Variations ◽  
Uncertainty Estimation ◽  
Retrieval Algorithm ◽  
Climate Data ◽  
Moist Air ◽  
Temperature And Humidity ◽  
Humidity Profiles

The Global Navigation Satellite System (GNSS) Radio Occultation (RO) is a key technique for obtaining thermodynamic profiles of temperature, humidity, pressure, and density in the Earth’s troposphere. However, due to refraction effects of both the dry air and water vapor at low altitudes, retrieval of accurate profiles is challenging. Here we introduce a new moist air retrieval algorithm aiming to improve the quality of RO-retrieved profiles in moist air and including uncertainty estimation in a clear sequence of steps. The algorithm first uses RO dry temperature and pressure and background temperature/humidity and their uncertainties to retrieve humidity/temperature and their uncertainties. These temperature and humidity profiles are then combined with their corresponding background profiles by optimal estimation employing inverse-variance weighting. Finally, based on the optimally estimated temperature and humidity profiles, pressure and density profiles are computed using hydrostatic and equation-of-state formulas. The input observation and background uncertainties are dynamically estimated, accounting for spatial and temporal variations. We show results from applying the algorithm on test datasets, deriving insights from both individual profiles and statistical ensembles, and from comparison to independent 1D-Variational (1DVar) algorithm-derived moist air retrieval results from Radio Occultation Meteorology Satellite Application Facility Copenhagen (ROM-SAF) and University Corporation for Atmospheric Research (UCAR) Boulder RO processing centers. We find that the new scheme is comparable in its retrieval performance and features advantages in the integrated uncertainty estimation that includes both estimated random and systematic uncertainties and background bias correction. The new algorithm can therefore be used to obtain high-quality tropospheric climate data records including uncertainty estimation.

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 Application of the Deep Neural Network in Retrieving the Atmospheric Temperature and Humidity Profiles from the Microwave Humidity and Temperature Sounder Onboard the Feng-Yun-3 Satellite

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4673
Author(s):  
Qiurui He ◽  
Zhenzhan Wang ◽  
Jiaoyang Li
Keyword(s):  
Neural Network ◽  
Remote Sensing ◽  
Bias Correction ◽  
Deep Neural Network ◽  
Microwave Remote Sensing ◽  
Atmospheric Temperature ◽  
Superior Performance ◽  
Atmospheric Parameters ◽  
Temperature And Humidity ◽  
Humidity Profiles

The shallow neural network (SNN) is a popular algorithm in atmospheric parameters retrieval from microwave remote sensing. However, the deep neural network (DNN) has a stronger nonlinear mapping capability compared to SNN and has great potential for applications in microwave remote sensing. The Microwave Humidity and Temperature Sounder (Beijing, China, MWHTS) onboard the Fengyun-3 (FY-3) satellite has the ability to independently retrieve atmospheric temperature and humidity profiles. A study on the application of DNN in retrieving atmospheric temperature and humidity profiles from MWHTS was carried out. Three retrieval schemes of atmospheric parameters in microwave remote sensing based on DNN were performed in the study of bias correction of MWHTS observation and the retrieval of the atmospheric temperature and humidity profiles using MWHTS observations. The experimental results show that, compared with SNN, DNN can obtain better bias-correction results when applied to MWHTS observation, and can obtain higher retrieval accuracy of temperature and humidity profiles in all three retrieval schemes. Meanwhile, DNN shows higher stability than SNN when applied to the retrieval of temperature and humidity profiles. The comparative study of DNN and SNN applied in different atmospheric parameter retrieval schemes shows that DNN has a more superior performance.

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