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Secondary ice productions (SIPs) can produce ice crystals with a number concentration much higher than that of ice nucleating particles in mixed-phase clouds and therefore influence cloud glaciation and precipitation. For midlatitude continental mesoscale convective systems (MCSs), how SIPs affect the microphysical properties and precipitation is still not clear. There are few studies of SIPs in midlatitude continental MCSs. This study investigates the roles of three SIPs (rime splintering, freezing drop shattering, and ice-ice collisional breakup) on a squall line case in North China on 18 August 2020 using the WRF model with a modified Morrison double-moment bulk microphysical scheme. Including SIPs, especially ice-ice collisional breakup, in the model simulations markedly improves the simulated convective area and convective precipitation rate of the squall line, while slightly improving the area and precipitation of the stratiform region. Within the mixed-phase layer in both the convective and stratiform regions of the squall line, ice-ice collisional breakup is the dominant process to generate ice crystals. In contrast, rime splintering generates an order of magnitude fewer ice crystals than ice-ice collisional breakup, while freezing drop shattering plays a negligible role due to the lack of large drops. Ice multiplication through ice-ice collisional breakup and rime splintering produces numerous snowflakes and graupel. This leads to enhanced depositional growth and weaker riming, which in turn weakens rime splintering. It is recommended to add SIP parameterization to the model.

This paper presents a novel self-packaged low-pass filter (LPF) based on the substrate-integrated suspended line (SISL) technique, employing a high-impedance line structure. The core circuit of the proposed LPF integrates three distinct transmission line technologies: stripline (SL), grounded coplanar waveguide (GCPW), and SISL. Leveraging these advanced techniques, the prototype LPF with a cutoff frequency (f0) of 3 GHz has been successfully designed and fabricated. Comprehensive measurements reveal that the LPF exhibits an insertion loss (S21) of greater than −0.74 dB within the pass-band, while maintaining a stop-band ranging from 5 GHz to 12.2 GHz, achieving a suppression level exceeding 15 dB. Additionally, the highest internal solid-line impedance reaches 110 Ω. Given its superior performance characteristics, the proposed LPF is highly suitable for application in radio frequency (RF) front-end systems, specifically for filtering and screening signals within designated frequency bands.

Microwave radiometer (MWR) demonstrates exceptional efficacy in monitoring the atmospheric temperature and humidity profiles. A typical inversion algorithm for MWR involves the use of radiosonde measurements as the training dataset. However, this is challenging due to limitations in the temporal and spatial resolution of available sounding data, which often results in a lack of coincident data with MWR deployment locations. Our study proposes an alternative approach to overcome these limitations by harnessing the Weather Research and Forecasting (WRF) model’s renowned simulation capabilities, which offer high temporal and spatial resolution. By using WRF simulations that collocate with the MWR deployment location as a substitute for radiosonde measurements or reanalysis data, our study effectively mitigates the limitations associated with mismatching of MWR measurements and the sites, which enables reliable MWR retrieval in diverse geographical settings. Different machine learning (ML) algorithms including extreme gradient boosting (XGBoost), random forest (RF), light gradient boosting machine (LightGBM), extra trees (ET), and backpropagation neural network (BPNN) are tested by using WRF simulations, among which BPNN appears as the most superior, achieving an accuracy with a root-mean-square error (RMSE) of 2.05 K for temperature, 0.67 g m −3 for water vapor density (WVD), and 13.98% for relative humidity (RH). Comparisons of temperature, RH, and WVD retrievals between our algorithm and the sounding-trained (RAD) algorithm indicate that our algorithm remarkably outperforms the latter. This study verifies the feasibility of utilizing WRF simulations for developing MWR inversion algorithms, thus opening up new possibilities for MWR deployment and airborne observations in global locations.

In order to improve the accuracy of return flow snowfall forecast in Beijing area, the three return flow snowfall cases occurring in Beijing area in February 2019 are analyzed by using the ERA5/GDAS reanalysis data and the HYSPLIT back trajectory model for the meteorological analysis and characterization of the water vapor transport. The results show that, for all the three cases, the water vapor content in the easterly flow is limited regardless of the typical or atypical return flow, and significant snowfall can be produced when there is a cooperation of the southerly water vapor channel. In the typical return flow case (Feb. 14), the high backward return flow and the Loop Inversion Trough cooperate, and the water vapor transport channel is deeper, which is conducive to snow. In the two atypical return flow cases (Feb. 6 and 12), the water vapor transport is concentrated in the lower layers of the atmosphere (below 850 hPa). The case of Feb. 12 has a significant contribution from the southerly water vapor t

A mesoscale convective system (MCS) embedded in a cold frontal cloud system over Beijing on July 16, 2018 was investigated using X-band dual-polarization radar observations from Fangshan Station and sounding data from the Beijing Observatory. This study focused on hydrometeor identification and microphysical characterization, yielding the following key findings. 1) The ice-phase hydromorphic species above the 0°C layer differed in different stages and regions of this MCS. From the stage of development to maturity to dissipation, the main hydromorphic species in the region with combined reflectance larger than 40 dBZ were graupel and snow, and the proportion of ice crystals was relatively low. In the region with combined reflectance between 20 and 40 dBZ, graupel, snow, and ice crystals were the main hydromorphic species. In these two regions, the proportion of graupel gradually decreased with time, while the proportion of snow and ice crystals gradually increased with time. In the region with combined reflect

为提高北京地区回流降雪预报的准确率,利用ERA5/GDAS全球格点再分析资料和HYSPLIT轨迹追踪模式,对2019年2月发生在北京地区的3次回流降雪过程进行天气学分析和水汽输送特征分析.结果表明,在3次回流降雪个例中,偏东气流中的水汽含量有限,当出现偏南水汽通道的配合时,可产生明显的降雪.在典型回流形势(2月14日)下,高后回流与河套倒槽配合,回流水汽输送通道更为深厚,利于降雪;在非典型回流形势(2月6日和12日)下,回流水汽输送集中于大气的低层(850 hPa以下).2月12日南支气流水汽输送贡献较大,对南支气流水汽输送的忽视是导致2月12日降雪漏报的原因之一.3次回流降雪个例在偏东和偏南路径上水汽输送至北京地区的时间与白天显著降雪的时段基本上对应,可作为预报回流降雪的关键因子.

For 200Gb/s net rates, cap probabilistic shaped PAM-8 with different Gaussian orders are experimentally compared against uniform PAM-8. In back-to-back and 5km measurements, cap-shaped 85-GBd PAM-8 with Gaussian order of 5 outperforms 71-GBd uniform PAM-8 by up to 2.90dB and 3.80dB in receiver sensitivity, respectively.

Objective Plasma fibrinogen is essential in thrombosis and fibrinolysis, yet its dynamic changes pre‐ and post‐intravenous thrombolysis (IVT) for predicting brain injury severity and prognosis in acute ischemic stroke (AIS) patients remain unclear. Aims This study examined how fibrinogen trends before and after IVT correlate with brain injury severity and clinical outcomes in IVT‐treated patients. Methods This multicenter study prospectively enrolled AIS patients treated with IVT at 16 hospitals and recorded their fibrinogen trends before and after thrombolysis. Levels of brain injury markers were measured to represent the extent of brain injury, including glial fibrillary acidic protein (GFAP), ubiquitin c‐terminal hydrolase L1 (UCH‐L1), S100β, and neuron‐specific enolase (NSE). Prognostic indicators included early neurological deterioration (END), hemorrhagic transformation, infarct volume, National Institutes of Health Stroke Scale (NIHSS) score at 7 days, 3‐month poor outcome (modified Rankin Scale [mRS] score > 1), and mortality. Results A total of 827 patients were enrolled, with 207 exhibiting elevated fibrinogen levels 24 h after IVT. Patients with elevated fibrinogen levels exhibited significantly higher levels of brain injury markers (GFAP, UCH‐L1, S100β), larger infarct volumes, higher NIHSS scores at 7 days, and a higher incidence of END and poor outcomes compared to those with non‐elevated fibrinogen levels. Both univariate and multivariate analyses identified elevated fibrinogen levels after IVT as an independent predictor of severe brain injury, larger infarct volume, higher NIHSS score, occurrence of END, and poor outcomes. Interpretation Elevated fibrinogen levels 24 h after IVT are independently associated with more severe brain injury and worse clinical outcomes in AIS patients.