For the second Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC-2) Global Positioning System radio occultation (GPS RO) neutral atmosphere retrieval, ionosphere error correction on bending angle is performed by combining either L2C or L2P signals with L1 at the University Corporation for Atmospheric Research (UCAR), Boulder, CO, USA. While the L2C is a civil signal, the encrypted L2P signal from high-noise occultations will lead to low-accuracy bending angle profiles. This study distinguishes high-noise COSMIC-2 L2P occultations using the L2P signal-to-noise ratio (SNR) and proposes an alternative ionosphere correction method by fitting and extrapolating the difference between the L1 bending angle and the bending angle derived from the MSIS 00 model above 35 km ( ${\alpha }_{\text {L1+M}}$ ). Statistical validations are performed based on over 110159 L2P occultations from January 2023 to June 2023. The comparison of $ {\alpha }_{\text {L1+M}}$ and L1 and L2P bending angle, derived from L2P occultations with SNR below 200 v/v ( ${\alpha }_{\text {{L}1}+{\text {ML}}}$ and ${\alpha }_{\text {{L}1+L}{2}{\text {PL}}}$ ), shows that the percentage passed quality control increased from 40.8% (39.5%) to 73.6% (69.0%) for rising (setting) occultations. The mean standard deviation (SD) of ${\alpha }_{\text {L1+M}}$ is 2.0% (1.9%) on impact heights between 19 and 30 km for rising (setting) occultations, which is obviously smaller than 2.6% (2.5%) for ${\alpha }_{\text {L1+L2PL}}$ profiles. Hence, it can be concluded that the proposed ionosphere correction method can be utilized for retrieving COSMIC-2 L2P occultations, and combined with L2P high SNR occultations, the COSMIC-2 L2P occultations can further enrich the amounts of effective profiles on numerical weather prediction (NWP) and climate research.

The E s layer is a thin layer that concentrates metallic ions in the mesosphere and lower thermosphere （MLT） region.When it occurs,it can affect the performance of the Global Navigation Satellite System and high/very high frequency （HF/VHF） radio communications.Previous studies mainly focused on the one-dimensional structure of E s layer in the vertical direction.However,due to the limitation of observations,the horizontal structure of E s layers is not yet fully understood.This study investigated the horizontal structure of E s layers using amateur radio data in the European sector during the summer of 2020.Statistical analysis shows that the horizontal structure of E s layer is mainly elongated in the east-west direction.In addition,we investigated the dynamics of the E s layers,which primarily propagates in the northeast-southwest direction with a speed of 50-200 m/s.The results provide us a way for obtaining the horizontal structure and dynamic features of E s layers,which can help improve our understanding of the formation and evolution of E s layers.

In this study,ionosonde observations over Fuke(19.5°N,109.1 °E),Wuhan(30.5°N,114.4°E),and Mohe(53.5°N,122.3°E)were analyzed to demonstrate the responses of the sporadic E()to the severe atmospheric disturbances caused by the Tonga volcanic eruptions on January 15,2022.The most prominent signature was the disappearance of the layer after～10:00 UT over Wuhan and Fuke,which was attributed to the vertical drift caused by the eruptions.The occurred intermittently after 13:00 UT following the arrival of the tropospheric Lamb wave.To examine the causal mechanism for the intermittence,we also included data of horizontal winds in the mesosphere and lower thermosphere region recorded by the meteor radars at Wuhan and Mohe in this study.The wind disturbances with periods of～20 hours contributed to the formation of the layer in the nighttime on January 15.

. Kelvin Helmholtz instability (KHI) is most likely to be the primary source 29 for clear-air turbulence that is of importance in pollution transfer and diffusion and 30 aircraft safety. It is exemplarily indicated by the critical value of Richardson ( Ri ) 31 number, which is typically taken as 1/4. However, Ri is fairly sensitive to the vertical 32 resolution of the dataset: a higher resolution systematically leads to a finer structure. 33 The study aims to evaluate the performance of ERA5 reanalysis (137 model levels) in 34 determining KHI spatial-temporal variabilities, by comparing it against a near-global 35 high-resolution (10-m) radiosonde dataset during years 2017 to 2022, and to further 36 highlight the global climatology and dynamical environment of KHIs. Overall, the 37 occurrence frequency of Ri <1/4 in the free atmosphere is inevitably underestimated 38 by the ERA5 reanalysis over all climate zones, compared to radiosonde, due largely to 39 the severe underestimation in wind shears. Otherwise, the occurrence frequency of 40 KHI indicated by Ri <1 in ERA5 is climatologically consistent with that from 41 radiosondes in the free troposphere, especially over the midlatitude and subtropics in 42 the Northern/Southern Hemisphere. Therefore, we infer that the threshold value of Ri 43 should be approximated as 1, rather than 1/4, when using ERA5 for the KHI 44 estimation. KHI occurrence frequencies revealed by both datasets exhibit significant 45 seasonal cycles over polar, midlatitude, and subtropics regions, and they are 46 consistently strong at heights of 10–15 km in the tropic region. In addition, the 47 frequency at low-levels is positively correlated with the standard derivation of 48 orography, and it is exceptionally strong over the Niño 3 region at heights of 6–13 km. 49 Furthermore, the dynamical environment of KHI favors strong wind shears probably 50 induced by the mean flows and the propagation of orographic or non-orographic 51 gravity waves. 52

At present,the main detection instruments for observing sporadic E(Es)layers are ground-based radars,dense networks of ground-based global navigation satellite system(GNSS)receivers,and GNSS radio occultation,but they cannot capture the whole picture of the horizontal structure of Es layers.This study employs the Whole Atmosphere Community Climate Model with thermosphere and ionosphere eXtension model(WACCM-X 2.1)to derive the horizontal structure of the ion convergence region(HSICR)to explore the shapes of the large-scale Es layers over East Asia for the period from June 1 to August 31,2008.The simulation produced the various shapes of the HSICRs elongated in the northwest-southeast,northeast-southwest,or composed of individual small patches.The close connection between Es layer critical frequency(foEs)and vertical ion convergence indicates that the HSICR is a good candidate for revealing and explaining the horizontal structure of the large-scale Es layers.

This brief report examines the ground-based total electron content (TEC) in Asian sector during August–October 2019, covering the period of a stratosphere sudden warming (SSW) occurred in Antarctica. The analysis reveals pronounced ionospheric day-to-day variability with distinct periodicities. The most dominant and long-lasting periodicities are quasi-10 days and quasi 14-day during September and October, while a quasi 6-day also present in September. The 10-day and 6-day TEC oscillations were attributed by previous studies solely to the Antarctic SSW while assuming negligible geomagnetic effects. By comparing co-located ground mesospheric wind observations, along with the interplanetary electric field (IEF) and geomagnetic activity (Kp index), we demonstrate that the quasi 14-day oscillation is mainly driven by low-level geomagnetic activities, while quasi-6 days oscillation is driven by mesospheric wind changes during the SSW. The 10-day oscillation, on the other hand, is driven by both IEF and mesospheric wind in September, but by IEF in October. These results demonstrate that low-level geomagnetic activities traditionally classified as “quiet conditions” can induce significant day-to-day oscillations in TEC, and their impacts should not be ignored when studying meteorological (e.g., SSWs) impacts on the ionosphere.

Atmospheric gravity waves (GWs) in the mesosphere-lower thermosphere (MLT) are crucial for the understanding of general circulation. However, their dynamical characteristics are hardly retrieved due to the difficulty in the high-resolution observation of wind. Therefore, this paper uses eight years (2013–2020) of meteor radar measurements in the MLT region at Mohe station (53.5°N, 122.3°E), China, to retrieve high-temporal-resolution mesospheric wind data and further evaluate the temporal variation of GW kinetic energy. As the detected meteor trails exceed 6, the wind velocity is recalculated using the least square algorithm method, significantly increasing the temporal resolution of wind from 1 h up to 5 min. This resolution is sufficiently high for the investigation of GW kinetic energy, which exhibits a high spatial-temporal variability. For instance, it is enhanced in the winter season during the period of 0200–1400 UT and in the spring season during the period of 0800–1300 UT. The similarity between the climatological characteristics of GWs in MLT and the seasonal variation of GW total energy in the troposphere, determined from high-resolution radiosondes near to Mohe station, suggests that the meteorology in the lower atmosphere could be an important source of GWs in the MLT region.

Solar eclipse is a daytime phenomenon that significantly disturbs the ionosphere, but whether the eclipse induces ionospheric irregularities in the nighttime remains unknown. In this study, we analyzed the dense total electron content (TEC) observations from the ground‐based Global Navigation Satellite System receivers over East and South Asia to examine the development of the irregularities in the nighttime on the day of the 21 June 2020 annular solar eclipse. The rate of TEC index (period <5 min) indicates the occurrence of the irregularities that evolve from the large or coarse structures with a period ranging from hours to dozens of minutes in the nighttime due to the eclipse. We take advantage of the data‐adaptive analysis method, Hilbert‐Huang transform, to derive the instantaneous amplitude and frequency of the TEC time series, which exposes the temporal and spatial evolutions of the irregularities from larger structures continuously.

Accurately calculating the magnetic acceleration noise is essential to designing the space inertial sensor and constructing its evaluation system. In view of the shortcomings of the magnetic acceleration noise calculation model, which considers the test mass (TM) as an ideal magnetic dipole rather than an entity, the Maxwell stress tensor method (MSTM) and virtual work principle method (VWPM), which consider the influence of the shape and size of the TM into account are adopted in this study. Through comparison, it is concluded that the non uniformities of the internal magnetic field and magnetization intensity of the TM are the reasons for the calculation error of the model, and when the magnetic susceptibility is <1 x 10(-2), the model can satisfy the requirement of the calculation accuracy. Finally, two specific signals of the near-interplanetary magnetic field and the magnetic field of a circuit board were measured in a magnetic shielding room (MSR), and the magnetic acceleration noises induced by the two magnetic environments were calculated. These can act as significant reference values for magnetic acceleration noise experiments in orbit and the layout of electronic devices in satellite engineering.

[研究目的]锌(Zn)是一种人体所必需的微量元素.利用区域地球化学调查数据,准确预测农作物中Zn含量,从而开展富Zn农产品开发规划仍存在较大难度.[研究方法]本文选择四川省邻水县为研究区,依据土地质量地球化学调查所获得的表层土壤、农作物及根系土中地球化学指标数据,系统研究了土壤与农作物中Zn含量和空间分布特征,分析了玉米、水稻吸收Zn的影响因素.[研究结果]邻水县表层土壤Zn含量范围为25.00～142.00 mg/kg,平均值为81.93 mg/kg,土壤Zn高值区主要分布在邻水县华蓥山碳酸盐岩和峨眉山玄武岩出露区.研究区玉米、水稻籽实平均Zn含量分别为17.18 mg/kg和11.20 mg/kg,富锌率分别为44.0％和8.2％.利用反向传播神经网络模型分别预测出邻水县富Zn玉米、富Zn水稻种植面积为235.34 km2、30.99 km2.[结论]影响研究区玉米、水稻籽实Zn生物富集主要因素有土壤Fe2O3、Mn、pH、SiO2/Al2O3、CaO、有机质以及营养元素P等;反向传播神经网络模型能较好地模拟籽实Zn元素与土壤理化性质的关系,可以应用于区域农作物Zn含量的计算.

研究地质高背景地区土壤中不同粒径铁锰结核地球化学特征,有助于厘清岩溶地区土壤中铁锰结核对重金属异常富集的影响及对重金属吸附固定的主控因素.本研究以广西南宁市和崇左市大新县表层土壤大样(0～20 cm)为对象,筛分出不同粒径的铁锰结核(0.3 ～0.5、0.5～1、1～2、2～4、4～6、6～8、＞8 mm)和对应土壤(＜2 mm)样品进行化学分析,研究不同粒径铁结核和锰结核重金属元素变化和主控因素以及重金属(Cd、Cr、Cu、Ni、Pb、Zn)在铁锰结核和对应土壤中的分布分配规律.结果 显示:铁结核和锰结核中,随着粒径变化,Fe2O3与Cr元素显示同步变化趋势,而MnO2与Cd、Cu、Ni、Pb、Zn等重金属变化趋势同步,重金属元素随粒径变化特点反映了铁锰结核形成及生长过程中铁元素控制着Cr元素的地球化学行为,而锰元素控制着Cd、Cu、Ni、Pb、Zn元素的地球化学行为.通过计算土壤中铁锰结核重金属元素含量的贡献比例,在铁结核中平均贡献比例为Cr (47.76％)＞Cd(24.91％) ＞Pb(18.44％) ＞Cu(16.26％) ＞Zn(14.77％) ＞Ni(10.41％),而在锰结核中平均贡献比例为Cr(45.25％)＞Cd(37.94％)＞Pb(25.86％)＞Cu(15.59％)＞Zn(13.79％)＞Ni(12.15％),说明岩溶区土壤中大部分重金属实际是被固定在铁锰结核中,且生物活性很低.因此,对高地质背景区土壤进行生态风险评价时,应扣除固定在铁锰结核中的重金属,这样才更科学更精确.

China’s Mars exploration mission has stimulated tremendous interest in planetary science exploration recently. To propose potential scientific research projects, this study presents a concept simulation for the measurement of Martian atmospheric winds using the Doppler Michelson interferometry technique. The simulation is based on the satellite instrument initially designed for the Dynamic Atmosphere Mars Observer(DYNAMO) project to measure vertical profiles of winds from the 1.27 μm airglow observations in the Martian atmosphere. A comprehensive DYNAMO measurement simulation forward model based on an orbit submodel, an atmospheric background field submodel, and an instrument submodel is developed using the Michelson equation. The simulated interferogram signal over the field of view(FOV) calculated by the forward model is associated with the filter transmittance function, column emission rate of airglow, wind velocity, temperature, and the Michelson phase. The agreement between the derived atmospheric signals from the simulated interferogram without altitude inversion and the input parameters used to initiate the forward model confirms the validity of the forward model.

Precipitation anomaly grades are usually defined by the percentage anomaly (Pa) or probability distribution (Pd) methods. However, the difference between the two may lead to different estimates for the same events, creating difficulty in judging the severity of the events. Here, we quantify the difference in measuring precipitation variability in China between Pa and Pd methods and analyze physical meaning and influencing factors of the difference. The results show that Pa tends to underestimate the domain of wetness (e.g., it underestimated 7.67% in June 2018) and overestimate/underestimate the severity of extreme wetness (>1.5 σ )/dryness (<–1.3 σ ) compared to the Pd method. Because precipitation has a positive skewed distribution, and precipitation maximum values have a larger influence on Pa than on Pd. On the other hand, uniform Pa thresholds for classifying drought grades at all stations are unreasonable. Because of an asymmetrical range of actual Pa value, Pa fails to symmetrically reflect the degree of drought and flood. Spatially, the large difference usually appears in the areas with extreme precipitation. Therefore, the more extreme precipitation stations, the greater the spatial dispersion of precipitation and the greater the total difference between Pa and Pd in whole China. We further find that the Pa‐Pd difference is significantly related to a concurrent warming of the tropical Indian Ocean and the tropical Pacific sea surface in spring. And the Pa‐Pd difference is rising at 0.022 σ /10a with the increase of extreme events associated with the ocean warming, which deserves attention from the decision‐making departments.

硒是生态环境中重要的微量元素之一,如何准确评估其生物有效性一直存在争议.在四川省广安市邻水县采集了60套农作物及其根系土样品,分析其Se含量和理化性质.同时基于梯度扩散膜技术对土壤有效Se含量进行分析,并对土壤有效Se含量的影响因素进行探究.结果表明,研究区土壤Se含量为0.15～2.42 mg/kg,均值为0.48 mg/kg,不同类型土壤Se含量差异明显,石灰土(1.06 mg/kg)>黄壤(0.78 mg/kg)>紫色土(0.28 mg/kg)>水稻土(0.27 mg/kg).石灰土和黄壤有机质含量和总铁(TFe2 O3)含量明显高于其他类型土壤.研究区内不同类型土壤的DGT-Se明显不同,与土壤Se含量分布相反.相关性分析表明土壤DGT-Se与Se含量、TFe2 O3含量、S含量、有机质含量、pH值、Al2 O3含量显著相关,受理化性质影响导致不同类型土壤中DGT-Se的差异.水稻根系土壤DGT-Se与水稻籽实Se含量显著正相关,用DGT可以较好地表达水稻-根系土系统中土壤Se的生物有效性.基于DGT技术评估预测区域尺度农业土壤有效Se含量时,需充分考虑土壤类型及其理化性质.

土壤地球化学背景值与基准值研究是地球科学领域重要基础性工作.《中国土壤地球化学参数》是在全国多目标区域地球化学调查基础上,基于高质量高精度大数据研究的重要成果.本文概述地球化学调查工作方法与样品测试质量等若干基本要求,说明大数据的获取方式与精度水准.主要从宏观尺度上论述中国土壤背景值与基准值变化特征,包括:①研究中国土壤地球化学背景值与全球地壳丰度比值特征,阐述中国土壤元素(氧化物)背景值相对于全球地壳丰度的总体特征和基本规律;②通过辽河流域、黄河流域、长江流域及珠江流域土壤元素(氧化物)背景值与地壳丰度对比,研究由北方至南方各大流域相对于全球丰度的变化特征;③通过上述各大流域与全国土壤背景值对比,研究各大流域分别在全国总背景中的变化特征;④以中国基本无人类影响的代表自然本底的第一环境土壤背景值为基准,研究代表人类深度影响的第二环境土壤地球化学富集特征;⑤通过对比国内各大流域和地区第一环境与第二环境土壤地球化学背景比值特征,研究全国不同自然环境和地理景观条件下元素指标富集与贫化规律等.《中国土壤地球化学参数》研究建立在地球化学大数据基础上,信息量巨大,内涵极为丰富,是我国地球化学历史上空前规模的具有里程碑意义的学术成就,为包括土壤学、生态学、环境学、生物学在内的地球科学领域提供基础信息,为全球变化、全球环境、全球治理重大科学问题研究提供重要依据,为国家自然资源、生态环保、农业农村及卫生健康等行业部门科学管理与科学决策提供评价标准.本文研究仅仅触及宏观层面的某些方面,就已经涌流出大量生态信息、自然规律与科学问题需要深化研究和应用实践.可以预见,随着中国土壤地球化学参数的深入研究与广泛应用,将促使地球化学更加深度融入国家经济社会发展,在国家发展大格局中发挥积极作用,国家经济社会发展也将会更加关注地球化学问题.本项调查与研究成果凝聚了广大地学工作者的辛劳和智慧,展现出严谨的科学精神和崇高的事业心与责任心,展示中国质量和中国精度,代表中国地学领域高质量发展方向.

氟是存在于自然环境中的一种人体必需的微量元素,其在环境中的缺乏或过剩可能导致健康问题.本文综述了氟在自然界如大气、岩石、土壤、水体、植物中的来源,分析了其形态及含量受环境影响的因素如地形、雨水淋溶、土壤母质、土壤酸碱度、土壤有机质等.氟的来源广泛,目前全球超过2.6亿人受氟带来的环境问题影响,因此开展健康风险评估具有重要意义.氟的健康风险评估常用的风险评估模型有危害系数(Hazard Quotient)、危害指数(Hazard Index),概率方法也常运用于风险分析中,目前还出现应用多途径暴露评估法对氟进行评估,不确定性和灵敏度的研究对于评估模型尤为关键.本文比较了传统模型的可行性和局限性,认为确定氟富集的途径,完善复合暴露评估的模式,考虑氟摄入的生物有效性,对于氟的健康风险评估十分必要;氟的健康风险评估下一步的研究还可以趋向于使用模型对氟的风险进行预测;对于氟的来源、赋存状态、迁移途径以及含量影响因素等仍然需要深入了解,全面评估其带来的健康风险.

依据四川省邻水县西部地区3447件表层土壤样品、59套水稻及其根系土样品和59套玉米及其根系土样品的数据资料,研究了土壤Se含量分布特征,建立了水稻、玉米籽实Se含量与其根系土元素含量的关系模型,进行了富Se农作物产地规划.研究结果表明:研究区土壤硒元素含量主要受其成土母质控制,碳质页岩、灰黑色玄武岩、深灰色灰岩成土母质分布区土壤Se平均含量较高,而侏罗系和三叠系地层区土壤Se平均含量较低;研究区水稻、玉米籽实富Se率分别为33.9％和98.3％,且重金属含量不超标,具备开发富硒农产品的潜力.农作物籽实Se含量主要与根系土中Se、S和有机质含量有关,通过作物籽实Se含量预测模型规划出研究区富Se水稻种植区面积为727 hm2,富Se玉米种植区面积16385 hm2.该认识为当地富硒农产品产地规划提供了科学依据,对提高农产品经济价值具有重要意义.

地质高背景的岩溶区土壤中普遍发育铁锰结核,且含量远高于非岩溶地区.为了解岩溶区土壤中铁锰结核的成因,选择广西桂中地区土壤(0～20 cm)中的铁锰结核为研究对象,通过光学显微镜(OP)、场发射扫描电子显微镜(FESEM)及能谱分析(EDS),结合岩溶区复杂的成土过程,对地质高背景地区土壤中铁锰结核的形成过程进行分析.结果 表明:岩溶区土壤中普遍发育两种结核,分别是铁结核和锰结核,宏观上结核呈现次圆状至椭圆状,粒径范围主要为0.5～4.0 mm,且均发育有环带结构和无环带结构结核.锰结核主要是以铁氧化物和锰氧化物为主,而铁结核内部是以铁氧化物为主.据上述结果和岩溶成土过程,提出地质高背景土壤中铁锰结核发育的过程:1)岩溶地区土壤在成土过程中,铁锰等元素发生不同程度的"浓集"作用,为结核的形成提供了丰富的物质来源;2)特殊的季节性干湿交替气候条件导致铁元素和锰元素的交替性沉淀,促进典型环带结构的形成,而无环带结构则可能代表结核形成的早期阶段;3)结核内部的微孔隙结构可以为微生物活动提供空间和物质流动提供通道,特殊气候环境条件富含有机质和微生物可能会促进铁锰结核的形成,最终形成岩溶区土壤中普遍发育的铁锰结核.

我国的农业发展经过了高产农业阶段和绿色农业阶段,目前已经逐步进入功能农业阶段.自然资源部中国地质调查局开展的土地质量地球化学调查在资源与环境领域发挥了重大作用.我们首先介绍了土地质量地球化学调查工作的产生背景和现状,简要总结了其在服务生态文明建设和功能农业方面的进展和成果:(1)发现大批优质特色富硒土地资源,积极服务乡村振兴;(2)查明符合国家质量标准的绿色、无污染耕地,服务生态农业发展;(3)估算主要农耕区土壤碳库变化,服务全球气候变化决策.同时阐述了面临的困难和存在的问题,并提出建议和对策.在向第二个一百年的奋斗目标前行迈进的重要历史时刻,做好土地质量地球化学调查和功能农业工作对于促进农业经济发展,解决"三农"问题具有重要的意义.