Application of Bias Correction to Improve WRF Ensemble Wind Speed Forecast

Surface wind speed forecast from an operational WRF Ensemble Prediction System (WEPS) was verified, and the system-bias representations of the WEPS were investigated. Results indicated that error characteristics of the ensemble 10-m wind speed forecast were diurnally variated and clustered with the usage of the planetary boundary layer (PBL) scheme. To correct the error characteristics of the ensemble wind speed forecast, three system-bias representations with decaying average algorithms were studied. One of the three system-bias representations is represented by the forecast error of the ensemble mean (BC01), and others are assembled from each PBC group (BC03) as well as an independent member (BC20). System bias was calculated daily and updated within a 5-month duration, and the verification was conducted in the last month, including 316 gauges around Taiwan. Results show that the mean of the calibrated ensemble (BC03) was significantly improved as the calibrated ensemble (BC20), but both demonstrated insufficient ensemble spread. However, the calibrated ensemble, BC01, with the best dispersion relation could be extracted as a more valuable deterministic forecast via the probability matched mean method (PMM).

Evaluation of the Interference of HbE on HbA1c Results on the Detection System Produced by Shenzhen Lifotronic

Objective: To analyze the interference of HbE on the HbA1c results on detection systems manufactured by Shenzhen Lifotronic. Methods: Volunteers were recruited from Zhongshan city, Guangdong province during June 2020 to November 2020. A total of 55 specimens were obtained, including 40 cases without HbE(23 cases in normal group and 17 cases in diabetes group) and 15 cases with HbE variant. HbA1c of these two groups (normal and HbE group) were analyzed by Shenzhen Lifotronic H8, H9 and GH-900Plus, Bio-Rad Variant II Turbo 2.0 and D-10 from USA, Arkray HA-8180 from Japan, statistical analysis was conducted on the difference between detection results of normal group and HbE variant group. Bio-Rad Variant II Turbo 2.0 was used as the comparison system to calculate the bias and to evaluate the interference of HbE on each system. Results: In normal group, the results of each detection system were comparable to those of Variant II Turbo 2.0, with a bias of -6%~6%. In HbE variant group,system bias of H8, H9, GH-900Plus and D-10 was within -6% and 6%, and the results showed no significant difference (P>0.05), while the negative bias of HA-8180 showed significant difference (P<0.05). Conclusion Compared with Bio-Rad Variant II Turbo 2.0, HbA1c can be correctly detected by H8, H9 and GH-900Plus system without the interference of HbE.

TP8.2.20 Gongs galore: phaleristic study of the relative risk of a healing art related new-year honour

Aims To compare proportional representation of healthcare specialty workers, in receipt of New Year honours (NYHs) and examine system bias. Methods Observational study of recipients of NYHs from 2010 to 2019 within the UK honours system including comparative analysis of proportional representation of the UK medical workforce Absolute risk of receiving a NYH, related to medical specialty, gender, and geographical region. Relative Risk (RR) of receiving an NYH for services to healthcare related to specialty. Results 11 207 NYHs were bestowed, with 368 (3.3%) awarded to healthcare professionals: 212 (57.6%) women, 156 (42.4%) men. The RR of a healthcare professional receiving a NYH was 0.76 (95% CI 0.68 to 0.84, p &lt; 0.001) when compared with the remaining UK workforce. Doctors received most NYHs (n = 181), with Public Health, Clinical Oncology, and General Medicine specialties most likely to be rewarded (RR 20.35 (CI 9.61 to 43.08, p &lt; 0.001), 8.43 (CI 2.70 to 26.30, p &lt; 0.001) and 8.22 (CI 6.22 to 10.86, p &lt; 0.001)) respectively; Anaesthetists received fewest NYHs (RR 0.52 (0.13 to 2.10), p = 0.305). Men were more likely to receive NYHs than women (OR 0.44, 95%CI 0.36 to 0.54; p &lt; 0.001). Two hundred and fifty-four NYHs (69.0%) were bestowed on residents of England (60, 16.3% London), 49 (13.3%) Scotland (p = 0.003), 39 (10.6%) Wales (p &lt; 0.001), and 26 (7.1%) Northern-Ireland (p &lt; 0.001). Conclusions Relative risk of receiving a NYH varied over 150-fold by specialty, two-fold by gender, and three-fold by geographical location. Public Health Physicians are perceived to be the pick of the parade.

Estimation of Inter-System Biases between BDS-3/GPS/Galileo and Its Application in RTK Positioning

For the development of a global navigation satellite system (GNSS), the third generation of BeiDou Navigation Satellite System (BDS-3) achieved full constellation for worldwide service on 23 June 2020. The new signals, B1C and B2a of BDS-3, further enhance the compatibility and interoperability between different GNSSs. In this study, we first assessed the quality of all the signals in BDS-3/GPS/Galileo. Then, to achieve the interoperability among BDS-3/GPS/Galileo, the inter-system bias (ISB), which appears if an inter-system difference exists between two GNSSs, was estimated at overlapping frequencies. Finally, we used the estimated ISBs in real-time kinematic (RTK) positioning. The results show the higher quality of the overlapping frequency B2a/L5/E5a than B1C/L1/E1 in terms of pseudo range multipath. The ISBs are stable both in the short term for one day and in the long term for over a year, which fit a zero-mean normal distribution well when the identical type of receiver is applied. Thus, it is reasonable to ignore the ISBs in the inter-system differences. With the estimated ISBs, the inter-system double-difference RTK can be achieved, which is called a tightly combined model (TCM) RTK. Compared with the traditional intra-system double-difference RTK, which is called a loosely combined model (LCM) RTK, the TCM RTK can achieve a higher success rate (SR) in terms of ambiguity resolution and higher positioning accuracy. In addition, the higher the cutoff elevation angle set, the greater the promotion can be obtained in SR. Even with a cutoff elevation angle of 50°, the SR of TCM is over 80%. Thus, it is important to apply TCM RTK when the observation conditions are limited, such as in dense jungles or the urban canyons.

Performance Evaluation of Precise Point Positioning for BeiDou-3 B1c/B2a Signals in the Global Range

With the construction and development of the BeiDou navigation satellite system (BDS), the precise point positioning (PPP) performance of the BDS is worthy of research. In this study, observational data from 17 stations around the world across 20 days are used to comprehensively evaluate the PPP performance of BDS B1c/B2a signals. For greater understanding, the results are also compared with the Global Positioning System (GPS) and BDS PPP performance of different signals and system combinations. The evaluation found root mean square (RMS) values of the static PPP in the north (N), east (E), and upward (U) components, based on the B1c/B2a frequency of BDS-3, to be 6.9 mm, 4.7 mm, and 26.6 mm, respectively. Similar to the static positioning, the RMS values of kinematic PPP in the three directions of N, E, and U are 2.6 cm, 6.0 cm, and 8.5 cm, respectively. Besides this, the static PPP of BDS-3 (B1cB2a) and BDS-2 + BDS-3 (B1IB3I) have obvious system bias. Compared with static PPP, kinematic PPP is more sensitive to the number of satellites, and the coordinate accuracy in three dimensions can be increased by 27% with the combination of GPS (L1L2) and BDS. Compared with BDS-2+BDS-3 (B1IB3I), the convergence time of BDS-3 (B1CB2a) performs better in both static and kinematic modes. The antenna model does not show a significant difference in terms of the effect of the convergence speed, though the number of satellites observed has a certain influence on the convergence time.

Modelling and assessment of Galileo and Galileo/GPS velocity determination with stand-alone receiver

Reasonable stochastic model and function model are the premise of accurate velocity determination, especially in the time-differenced carrier-phase (TDCP) method. This paper presents, first, an elevation-dependent stochastic model (ESM), and then gives a simplified and unified Galileo/GPS combined TDCP function model, where the inter-system bias (ISB) variations are analysed based on correlation coefficients and the scaled sensitivity matrix. To evaluate the performance of the proposed models, datasets collected at 10 multi-GNSS experiment (MGEX) stations and a vehicle kinematic experiment are employed. The results indicate that the ESM model can improve the accuracy of the velocity solution, especially for the Galileo/GPS combined system, in comparison with the equivalent weight ratio method. In contrast to the Galileo-only velocity solution, the Galileo/GPS combined velocity solution can bring improvements of about 1–1⋅5 mm/s, 0⋅5 mm/s and 1⋅5–2⋅5 mm/s in East, North and Up components, respectively. Compared with the traditional Galileo/GPS TDCP model, the simplified and unified model shows no obvious differences in all components in the environment with more visible satellites, but it performs better in a challenging environment with few visible satellites.