Implications of Dynamic Interactions between Meteorological Patterns and Surface Water Quality on Environmental Health—A Case Study of the Nairobi River

Urban areas face significant challenges in maintaining water quality amidst increasing urbanization and changing climatic patterns. This study investigates the complex interplay between meteorological variables and water quality parameters in Nairobi City, focusing on the impacts of rainfall and temperature on surface water quality. Data from multiple sources, including the Water Resources Authority, Nairobi Water and Sewerage Company, and the World Bank’s Climate Change Knowledge Portal, were analyzed to assess the relationships between meteorological variables (rainfall and temperature) and water quality parameters (such as electroconductivity, biochemical oxygen demand, chloride, and pH). The analysis reveals varying impacts of rainfall and temperature on different water quality parameters. While parameters like iron and pH show strong relationships with both rainfall and temperature, others such as ammonia and nitrate exhibit moderate relationships. Additionally, the study highlights the influence of runoff, urbanization, and industrial activities on water quality, emphasizing the need for holistic management approaches. Recommendations encompass the establishment of annual publications on Nairobi River water quality, online accessibility of water quality data, development of hydrological models, spatial analysis, and fostering cross-disciplinary research collaborations. Implementing these recommendations can enhance water quality management practices, mitigate risks, and safeguard environmental integrity in Nairobi City.

Comparison between ozonesonde measurements and satellite retrievals over Beijing,China

从2013年开始,作者团队使用自主研发电化学原理臭氧探空仪在华北平原北京地区进行每周一次观测.本研究首次使用2013-2019年期间北京地区臭氧探空数据评估Aqua卫星搭载大气红外探测仪(AIRS)和Aura卫星搭载微波临边探测器(MLS)反演垂直臭氧廓线,并对比臭氧探空,AIRS和Aura卫星搭载臭氧监测仪(OMI)臭氧柱总量结果.尽管臭氧探空与卫星反演垂直臭氧廓线在局部高度处差异较大,但整体来说两者较为接近(相对偏差大多<10%).臭氧探空,AIRS和OMI三种仪器测量臭氧柱总量的年变化特征较为一致,其年均臭氧柱总量分别为351.8±18.4 DU,348.8±19.5 DU和336.9±14.2 DU.后续对国内多站点观测数据分析将有助于进一步理解臭氧探空与卫星反演臭氧资料在不同区域的一致性.

A rapid assessment of MWRI-RM/FY3G brightness temperature

2023年4月发射的FY-3G上搭载17个频率的测雨微波成像仪(MWRI-RM),其业务定标的微波亮温(Tb)数据于2023年10月23日公开发布.本文比对了发布10天的MWRI-RM与全球降水测量(GPM)卫星上的微波成像仪(GMI)相匹配的Tb数据,并借助辐射传输模式进行双差分(DD)交叉定标分析,旨在快速评估新一代MWRI-RM观测数据质量.观测比较表明,MWR1-RM与GMI测量的Tb一致性很好,大多通道的平均偏差(MBE)和均方根误差(RMSE)均小于1K.两种传感器由于观测角度略有不同在水面产生约0.5 K差异.DD分析也展示出MWRI-RM的大多数通道性能与GMI相当接近,尤其是首次启用的高频166 GHz和183 GHz.

A multi-purpose prototype test system for mechanical behavior of tunnel supporting structure: Development and application

A multi-purpose prototype test system is developed to study the mechanical behavior of tunnel sup-porting structure,including a modular counterforce device,a powerful loading equipment,an advanced intelligent management system and an efficient noncontact deformation measurement system.The functions of the prototype test system are adjustable size and shape of the modular counterforce structure,sufficient load reserve and accurate loading,multi-connection linkage intelligent management,and high-precision and continuously positioned noncontact deformation measurement.The modular counterforce structure is currently the largest in the world,with an outer diameter of 20.5 m,an inner diameter of 16.5 m and a height of 6 m.The case application proves that the prototype test system can reproduce the mechanical behavior of the tunnel lining during load-bearing,deformation and failure processes in detail.

Design and experimental results of a 28 GHz,400 kW gyrotron for electron cyclotron resonance heating

A high-power 28 GHz gyrotron has been successfully developed at the Institute of Applied Electronics,China Academy of Engineering Physics.This gyrotron was designed for electron cyclotron resonance heating(ECRH)in the spherical tokamak XL-50.A diode magnetron injection gun was designed to produce the required gyrating electron beam.The gyrotron operates in the TE8,3mode in a cylindrical open cavity.An internal quasi-optical mode converter was designed to convert the operating mode into a fundamental Gaussian wave beam and separate the spent electron beam from the outgoing microwave power.A tube has been built and successfully tested.The operational frequency of the tube is 28.1 GHz.For beam parameters at an accelerating voltage of 71 kV and beam current of 16 A,the gyrotron has delivered an output power of 400 kW,with a pulse length of 5 s.The output efficiency is about 50%with a singlestage depressed collector.The gyrotron has been installed on the XL-50 and has played an important role in the ECRH experiments.

Evaluation of the Long-term Performance of Microwave Radiation Imager Onboard Chinese Fengyun Satellites

Accurate brightness temperature(BT)is a top priority for retrievals of atmospheric and surface parameters.Microwave Radiation Imagers(MWRIs)on Chinese Fengyun-3(FY-3)serial polar-orbiting satellites have been providing abundant BT data since 2008.Much work has been done to evaluate short-term MWRI observations,but the long-term performance of MWRIs remains unclear.In this study,operational MWRI BTs from 2012–19 were carefully examined by using simultaneous Advanced Microwave Scanning Radiometer 2(AMSR2)BTs as the reference.The BT difference between MWRI/FY3B and AMSR2 during 2012–19 increased gradually over time.As compared with MWRI/FY3B BTs over land,those of MWRI/FY3D were much closer to those of AMSR2.The ascending and descending orbit difference for MWRI/FY3D is also much smaller than that for MWRI/FY3B.These results suggested the improvement of MWRI/FY3D over MWRI/FY3B.A substantial BT difference between AMSR2 and MWRI was found over water,especially at the vertical polarization channels.A similar BT difference was found over polar water based on the simultaneous conical overpassing(SCO)method.Radiative transfer model simulations suggested that the substantial BT differences at the vertical polarization channels of MWRI and AMSR2 over water were partly contributed by their difference in the incident angle;however,the underestimation of the operational MWRI BT over water remained a very important issue.Preliminary assessment of the operational and recalibrated MWRI BT demonstrated that MWRI BTs were substantially improved after the recalibration,including the obvious underestimation of the operational MWRI BT at the vertical polarization channels over water was corrected,and the time-dependent biases were reduced.

一道高考试题的解题反思与备考建议

本文对一道高考试题做了解题反思,给出了多种解法,并进一步给出了考点分析和备考建议.

一道高考试题背后的高等数学背景

解读了一道高考试题与高等数学的联系及其初等、高等两种解法,又给出了两道同类型的高考试题和相应解法,对高三数学教学有所帮助.

中空四氧化三钴纳米球镶嵌的氮掺杂多孔碳纳米纤维:锂-氧电池氧电极双功能催化剂

随着全球人口数量快速增长和科技不断进步,对能源需求逐步增加,但化石能源日渐枯竭,同时环境问题日趋严重.因此,亟需开发新型、绿色、高效的能源以及能源装置,以保障清洁能源的可持续利用.锂-氧电池因其能量密度高、环境友好等优点受到了人们的广泛关注,并被认为是替代锂离子电池的新储能系统之一.然而,对于锂-氧电池仍需解决诸如能量密度低于理论值、倍率性能差和循环寿命短等难题.开发高效稳定的氧电极催化剂是解决上述问题的关键手段之一.在众多潜在的过渡金属氧化物催化剂中,四氧化三钴因其地壳丰度高、成本低和性能优异等优点成为研究热点.本文采用静电纺丝技术,结合热处理技术,成功制备了中空四氧化三钴纳米球镶嵌的多孔碳纳米纤维复合催化剂(H-Co_(3)O_(4)-CNFs),系统地研究了其氧还原反应(ORR)和析氧反应(OER)的电催化性能,以及作为锂-氧电池正极催化剂的电化学性能.结果表明,在碱性电解质中,H-Co_(3)O_(4)-CNFs具有较好的ORR/OER活性,展现出较好的双功能催化性能.H-Co_(3)O_(4)-CNFs作为锂-氧电池的氧电极催化剂材料,在100 mA g^(‒1)电流密度下的过电位为1.35 V,电池的放电比容量达到6134 mAh g^(‒1);当电流密度增加至800 mA g^(‒1)时,放电比容量仍能保持68.5%.在充放电电流密度为100 mA g^(‒1),限制容量为500 mAh g‒1的条件下,电池能保持150圈的稳定循环.H-Co3O4-CNFs催化剂较好的催化性能可归因于:(1)氮掺杂的多孔碳纤维具有良好的导电性和快速的电子传输能力;(2)多孔结构增大了电解液和催化剂活性位点的接触面积,并为放电产物过氧化锂的形成和分解提供了场所.另外,其良好的循环性能得益于裸露的Co_(3)O_(4)和嵌入纤维中的Co_(3)O_(4)形成的两种独立活性位点,这使其在ORR和OER过程中均有可用的催化活性位点,并在放电和充电过程中交替发挥作用.综上,本文研究结果为高效氧电极催化剂的设计提供了新思路。

Dynamic and Thermodynamic Features of Low and Middle Clouds Derived from Atmospheric Radiation Measurement Program Mobile Facility Radiosonde Data at Shouxian, China

By using the radiosonde measurements collected at Shouxian,China,we examined the dynamics and thermodynamics of single- and two-layer clouds formed at low and middle levels.The analyses indicated that the horizontal wind speed above the cloud layers was higher than those within and below cloud layers.The maximum balloon ascent speed（5.3 m s^-1） was located in the vicinity of the layer with the maximum cloud occurrence frequency（24.4%）,indicating an upward motion（0.1-0.16 ms^-1）.The average thickness,magnitude and gradient of the temperature inversion layer above single-layer clouds were117±94 m,1.3±1.3℃ and 1.4±1.5℃（100 m）^-1,respectively.The average temperature inversion magnitude was the same（1.3℃） for single-low and single-middle clouds;however,a larger gradient[1.7±1.8℃（100 m）^-1]and smaller thickness（94±67 m） were detected above single-low clouds relative to those above single-middle clouds[0.9±0.7℃（100 m）^-1 and157±120 m].For the two-layer cloud,the temperature inversion parameters were 106±59 m,1.0±0.9℃ and 1.0±1.0℃（100 m）^-1 above the upper-layer cloud and 82 ± 60 m,0.6±0.9℃ and 0.7±0.6℃（100 m）^-1 above the low-layer cloud.Absolute differences between the cloud-base height（cloud-top height） and the lifting condensation level（equilibrium level）were less than 0.5 km for 66.4%（36.8%） of the cases analyzed in summer.

Comprehensive Marine Observing Experiment Based on High-Altitude Large Unmanned Aerial Vehicle(South China Sea Experiment2020 of the “Petrel Project”)

In collaboration with 12 other institutions, the Meteorological Observation Center of the China Meteorological Administration undertook a comprehensive marine observation experiment in the South China Sea using the Yilong-10 high-altitude large unmanned aerial vehicle(UAV). The Yilong-10 UAV carried a self-developed dropsonde system and a millimeter-wave cloud radar system. In addition, a solar-powered unmanned surface vessel and two drifting buoys were used. The experiment was further supported by an intelligent, reciprocating horizontal drifting radiosonde system that was deployed from the Sansha Meteorological Observing Station, with the intent of producing a stereoscopic observation over the South China Sea. Comprehensive three-dimensional observations were collected using the system from 31 July to2 August, 2020. This information was used to investigate the formation and development processes of Typhoon Sinlaku(2020). The data contain measurements of 21 oceanic and meteorological parameters acquired by the five devices, along with video footage from the UAV. The data proved very helpful in determining the actual location and intensity of Typhoon Sinlaku(2020). The experiment demonstrates the feasibility of using a high-altitude, large UAV to fill in the gaps between operational meteorological observations of marine areas and typhoons near China, and marks a milestone for the use of such data for analyzing the structure and impact of a typhoon in the South China Sea. It also demonstrates the potential for establishing operational UAV meteorological observing systems in the future, and the assimilation of such data into numerical weather prediction models.

Design and preliminary test of a 105/140 GHz dual-frequency MW-level gyrotron

A dual-frequency(105/140 GHz)MW-level continuous-wave gyrotron was developed for fusion application at Institute of Applied Electronics,China Academy of Engineering Physics.This gyrotron employs a cylindrical cavity working in the TE18,7 mode at 105 GHz and the TE24,9 mode at 140 GHz.A triode magnetron injection gun and a built-in quasi-optical mode converter were designed to operate at these two frequencies.For the proof-test phase,the gyrotron was equipped with a single-disk boron nitride window to achieve radio frequency output with a power of~500 k W for a short-pulse duration.In the preliminary short-pulse proof-test in the first quarter of2021,the dual-frequency gyrotron achieved output powers of 300 k W at 105 GHz and 540 k W at140 GHz,respectively,under 5 Hz 1 ms continuous pulse-burst operations.Power upgrade and pulse-width extension were hampered by the limitation of the high-voltage power supply and output window.This gyrotron design was preliminarily validated.

First Rocketsonde Launched from an Unmanned Semi-submersible Vehicle

The unmanned semi-submersible vehicle(USSV) developed by the unmanned surface vehicle team of the Institute of Atmospheric Physics is an unmanned, rugged, and high-endurance autonomous navigation vessel designed for the collection of long-term, continuous and real-time marine meteorological measurements, including atmospheric sounding in the lower troposphere. A series of river and sea trials were conducted from May 2016 to November 2017, and the first rocketsonde was launched from the USSV. Real-time meteorological parameters in the marine atmospheric boundary layer(MABL) were obtained, including sea surface temperature, and vertical profiles of the pressure, temperature, relative humidity, wind speed,and wind direction. These data are extremely useful and important for research on air–sea interactions, sea surface heat and latent heat flux estimations, MABL modeling, and marine satellite product validation.

Analysis of Low-level Temperature Inversions and Their Effects on Aerosols in the Lower Atmosphere

High-quality and continuous radiosonde, aerosol and surface meteorology datasets are used to investigate the statistical characteristics of meteorological parameters and their effects on aerosols. The data were collected at the Atmospheric Radiation Measurement Southern Great Plains climate research facility during 2000–15. The parameters and vertical distribution of temperature inversion layers were found to have strong diurnal and seasonal changes. For surface-based temperature inversion (SBI), the mean frequency and depth of temperature inversion layers were 39.4% and 198 m, respectively. The temperature difference between the top and bottom of SBI was 4.8℃, and so the temperature gradient was 2.4℃(100 m)^-1. The detailed vertical distributions of temperature inversion had been determined, and only the temperature inversion layers below 1000 m showed diurnal and seasonal variations. Mean surface aerosol number concentrations increased by 43.0%, 21.9% and 49.2% when SBIs were present at 0530, 1730 and 2330 LST, respectively. The effect of SBI on surface aerosol concentration was weakest in summer (18.1%) and strongest in winter (58.4%). During elevated temperature inversion events, there was no noticeable difference in surface aerosol number concentrations. Temperature differences and temperature gradients across SBIs correlated fairly well with aerosol number concentrations, especially for temperature gradients. The vertical distribution of aerosol optical properties with and without temperature inversions was different. Surface aerosol measurements were representative of the air within (below), but not above, SBIs and EIs. These results provide a basis for developing a boundary layer aerosol accumulation model and for improving radiative transfer models in the lower atmosphere.

Intensive Radiosonde Measurements of Summertime Convection over the Inner Mongolia Grassland in 2014:Difference between Shallow Cumulus and Other Conditions

Using radiosonde measurements from 26 July to 30 July 2014 at Baiqi over the Inner Mongolia grassland of China, the vertical structure of shallow cumulus （SCu） clouds and associated environmental conditions were investigated. The cloud base height and the cloud top height of SCu was 3.4 km and 5 km, respectively. The temperature of the SCu layer was less than 0℃. The horizontal advection of specific humidity was smaller than the vertical transport in the atmosphere below 5 km. Above 5 km, the thermodynamic structure of the atmosphere remained stable. At the interface of the cloud layer and free air atmosphere, there was obvious wind shear and a temperature inversion （-2.9~C）. Comparisons of environmental parameters associated with cumulus congestus, rain and clear days, showed that the formation of SCu was characterized by a higher Bowen ratio （high sensible heat flux and low latent heat flux）, which indicated intensive turbulence in the boundary layer. The formation of SCu was associated with the boundary layer height exceeding the lifting condensation level. The maintenance of SCu was likely associated with the lower convective available potential energy, weak wind shear, and weak subsidence of the synoptic system, which did not favor the dramatic vertical development of SCu and thereby the transformation of SCu to cumulus congestus.

IAP's Solar-Powered Unmanned Surface Vehicle Actively Passes through the Center of typhoon Sinlaku(2020)

The solar-powered marine unmanned surface vehicle(USV) developed by the USV team of the Institute of Atmospheric Physics is a rugged, long-duration, and autonomous navigation vessel designed for the collection of longrange, continuous, real-time, meteorological and oceanographic measurements, especially under extreme sea conditions(sea state 6–7). These solar-powered USVs completed a long-term continuous navigation observation test over 26 days.During this time, they coordinated double-USV observations and actively navigated into the path of Typhoon Sinlaku(2020) before collecting data very close to its center during the 2020 USV South China Sea Typhoon Observation Experiment. Detailed high temporal resolution(1 min) real-time observations collected by the USV on the typhoon were used for operational typhoon forecasting and warning for the first time. As a mobile meteorological and oceanographic observation station capable of reliable, automated deployment, data collection, and transmission, such solar-powered USVs can replace traditional observation platforms to provide valuable real-time data for research, forecasting, and early warnings for potential marine meteorological disasters.

Short-term Ocular Toxicity and Eye Irritation Tests Following Application of Sufentanil in Rabbits

Purpose:.To test the safe clinical application of sufentanil as topical ophthalmic drops by examining treated rabbit eyes for ophthalmic irritation signs or short-time toxic reactions.Methods:.Twenty-four rabbits were randomly divided into 8groups(n=3): The ocular toxicity at 14 d after eye drop administration was evaluated in groups 1 to 4, and at 30 d postadministration in groups 5 to 8..Groups 1 and 5 were treated with blank vehicle and served as normal controls..The left eyes of rabbits in groups 2 and 6 were exposed to low-dose sufentanil(5 μg, 2 drops within 5 min), groups 3 and 7 received moderate-dose sufentanil.(7.5 μg, 3 drops within 10 min),and groups 4 and 8 received high-dose sufentanil(10 μg,.4drops within 15 min). As self-controls, the right eyes of each rabbit were administered an equivalent amount of sodium chloride(9 g / L) at the same drop intervals. At 14 and 30 d after exposure to sufentanil,.ophthalmic irritation signs were evaluated and corneas were stained with fluorescein and observed by slit-lamp microscopy..Corneal endothelial counts were performed and toxic reactions were evaluated.Results: Multiple parameters were compared in the control and experimental groups by visual inspection and slit-lamp examination at 14 and 30 d after sufentanil administration..No evidence of irritation signs(including corneal opacity,.conjunctival congestion, or edema), eye secretions, iris abnormalities,.or temporal eye closure were noted..Corneal endothelial cell counts did not significantly differ between the control and experimental groups..Light microscopy revealed no pathological or morphological injury to the cornea, conjunctiva, iris, ciliary body, retina, or optic nerve in either group.The same observation outcomes were noted at 14 and 30 d after administration.Conclusion:.Single ocular administration of sufentanil at a dose of 5-10 μg in rabbits yields no ocular irritation or toxic responses at 14 or 30 d following eye drop delivery.

A Comparison of Cloud Layers from Ground and Satellite Active Remote Sensing at the Southern Great Plains ARM Site

Using the data collected over the Southern Great Plains ARM site from 2006 to 2010, the surface Active Remote Sensing of Cloud （ARSCL） and CloudSat-CALIPSO satellite （CC） retrievals of total cloud and six specified cloud types [low, midlow （ML）, high-mid-low （HML）, mid, high-mid （HM） and high] were compared in terms of cloud fraction （CF）, cloud-base height （CBH）, cloud-top height （CTH） and cloud thickness （CT）, on different temporal scales, to identify their respective advantages and limitations. Good agreement between the two methods was exhibited in the total CF. However, large discrepancies were found between the cloud distributions of the two methods at a high （240-m） vertical grid spacing. Compared to the satellites, ARSCL retrievals detected more boundary layer clouds, while they underestimated high clouds. In terms of the six specific cloud types, more low- and mid-level clouds but less HML- and high-level clouds were detected by ARSCL than by CC. In contrast, the ARSCL retrievals of ML- and HM-level clouds agreed more closely with the estimations from the CC product. Lower CBHs tended to be reported by the surface data for low-, ML- and HML-level clouds; however, higher CTHs were often recorded by the satellite product for HML-, HM- and high-level clouds. The mean CTs for low- and ML-level cloud were similar between the two products; however, the mean CTs for HML-, mid-, HM- and high-level clouds from ARSCL were smaller than those from CC.

A multi-location joint field observation of the stratosphere and troposphere over the Tibetan Plateau

The unique geographical location and high altitude of the Tibetan Plateau can greatly influence regional weather and climate.In particular, the Asian summer monsoon(ASM) anticyclone circulation system over the Tibetan Plateau is recognized to be a significant transport pathway for water vapor and pollutants to enter the stratosphere. To improve understanding of these physical processes, a multi-location joint atmospheric experiment was performed over the Tibetan Plateau from late July to August in 2018, funded by the fiveyear(2018–2022) STEAM(stratosphere and troposphere exchange experiment during ASM) project, during which multiple platforms/instruments—including long-duration stratospheric balloons, dropsondes, unmanned aerial vehicles, special sounding systems, and ground-based and satellite-borne instruments—will be deployed. These complementary methods of data acquisition are expected to provide comprehensive atmospheric parameters(aerosol, ozone, water vapor, CO_2, CH_4, CO, temperature, pressure,turbulence, radiation, lightning and wind); the richness of this approach is expected to advance our comprehension of key mechanisms associated with thermal, dynamical, radiative, and chemical transports over the Tibetan Plateau during ASM activity.

Statistics of cloud heights over the Tibetan Plateau and its surrounding region derived from CloudSat data

Cloud-radiation interaction has a large impact on the Earth＇s weather and climate change, and clouds with different heights cause different radiative forcing. Thus, the information on the statistics of cloud height and its variation in space and time is very important to global climate change studies. In this paper, cloud top height （CTH）, cloud base height （CBH） and cloud thickness over regions of the Tibetan Plateau, south slope of the plateau and South Asian Monsoon are analyzed based on CloudSat data during the period from June 2006 to December 2007. The results show that frequency of CTH and CBH in unit area over the studied regions have certain temporal-spatial continuity. The CTH and CBH of different cloud types have different variation scopes, and their seasonal variations are distinct. Cloud thickness is large （small） in summer （winter）, and the percentages of different cloud types also have certain regularity.