Journal of Atmospheric and Solar-Terrestrial Physics最新文献_第2页

Changes in turbulent processes caused by atmospheric gravity waves from troposphere 对流层大气重力波引起的湍流过程变化

IF 1.8 4区地球科学 Q3 GEOCHEMISTRY & GEOPHYSICS

Journal of Atmospheric and Solar-Terrestrial Physics

Pub Date : 2024-10-22 DOI: 10.1016/j.jastp.2024.106364

Liudmyla Kozak , Istvan Ballai , Viktor Fedun , Elena A. Kronberg , Aljona Bloecker , Bohdan Petrenko

We have determined that changes in temperature and wind speed recorded in the Earth‘s upper atmosphere above tropospheric sources (hurricanes) can be explained by the propagation of atmospheric gravity waves (AGW). We carried out modeling of the propagation of AGW with a period of 65 min and

k_{x} = 1 0^{- 5}

m⁻¹ using multi-layer methods in a non-homogeneous, non-isothermal atmosphere, taking into account viscosity and thermal conductivity. We obtained that disturbances in the horizontal component of the velocity are five times greater than the increase in the vertical component of the velocity, and temperature changes can reach 30 K. We should note that the disturbances of temperature and pressure as a result of AGW spreading are superimposed onto the usual view of changes of pressure and temperature with the altitude and reach the maximum amplitude in the range from 90 to 100 km. The obtained changes in the temperature of the upper atmosphere and the velocity with height as a result of the presence of AGW made it possible to estimate the values of the coefficients of turbulent viscosity and thermal conductivity in the upper atmosphere of the Earth above tropospheric energy sources. Intensification of turbulent processes was recorded in the range of altitudes from 75 to 100 km.

我们已经确定，在对流层源（飓风）上方的地球高层大气中记录到的温度和风速变化可以用大气重力波（AGW）的传播来解释。我们使用多层方法在非均质、非等温大气中对周期为 65 分钟、kx=10-5 m-1 的 AGW 传播进行了建模，并考虑了粘度和导热性。我们得到的结果是，速度水平分量的扰动比速度垂直分量的增加大五倍，温度变化可达 30 K。我们应该注意到，AGW 传播导致的温度和压力扰动与压力和温度随高度变化的通常观点相叠加，并在 90 至 100 千米范围内达到最大振幅。由于存在 AGW，高层大气温度和速度随高度的变化得以估算对流层能量源上方地球高层大气的湍流粘度和热传导系数的值。在 75 至 100 公里的高度范围内记录到湍流过程的加剧。

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引用次数: 0

Dynamical complexity and multifractal analysis of geomagnetic activities at high temporal scales over three solar cycles 三个太阳周期高时间尺度地磁活动的动态复杂性和多分形分析

IF 1.8 4区地球科学 Q3 GEOCHEMISTRY & GEOPHYSICS

Journal of Atmospheric and Solar-Terrestrial Physics

Pub Date : 2024-10-21 DOI: 10.1016/j.jastp.2024.106380

Samuel Ogunjo , Joshua Akinsusi , Babatunde Rabiu , Ibiyinka Fuwape

Activities in geospace occur at different time scales. Understanding geomagnetic activity at high temporal scales will give insight into fast dynamics in geospace. This study aims to investigate dynamical complexities in geomagnetic activities at a high temporal scale across three solar cycles. Geomagnetic activities, as represented by 5-min SYM-H data, were considered in this study over three solar cycles (22–24) from 1986 to 2019. Chaos analysis using sample entropy, Lyapunov exponent, and correlation dimension indicates that the geomagnetic activities are driven by intrinsic complex and chaotic processes. Positive Lyapunov exponent values between 0.13 and 0.18, 0.15–0.18, and 0.16–0.19 were obtained for solar cycles 22, 23, and 24 respectively. Furthermore, geomagnetic activities were also found to have multifractal structures driven by high fractal exponents with fine structures. A positive relationship was obtained between the annual mean values of SYM-H and the degree of complexity. It is concluded that geomagnetic activities have a short prediction horizon.

地球空间的活动发生在不同的时间尺度上。了解高时间尺度的地磁活动将有助于深入了解地球空间的快速动力学。本研究旨在研究三个太阳周期中高时间尺度地磁活动的动态复杂性。本研究考虑了从 1986 年到 2019 年三个太阳周期（22-24）中以 5 分钟 SYM-H 数据为代表的地磁活动。利用样本熵、Lyapunov 指数和相关维度进行的混沌分析表明，地磁活动是由内在的复杂混沌过程驱动的。太阳周期 22、23 和 24 的李亚普诺夫指数分别为 0.13 至 0.18、0.15 至 0.18 和 0.16 至 0.19。此外，研究还发现地磁活动具有多分形结构，由具有精细结构的高分形指数驱动。SYM-H 的年平均值与复杂程度之间存在正相关关系。结论是地磁活动的预测范围较短。

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引用次数: 0

Aspect sensitivity measurement of backscattering radar echoes from 205 MHz Stratosphere–Troposphere radar at a tropical coastal station 在热带海岸站测量 205 MHz 平流层-对流层雷达反向散射雷达回波的高宽比灵敏度

IF 1.8 4区地球科学 Q3 GEOCHEMISTRY & GEOPHYSICS

Journal of Atmospheric and Solar-Terrestrial Physics

Pub Date : 2024-10-19 DOI: 10.1016/j.jastp.2024.106367

Dhanya R. , Anju Pradeep , Rakesh V. , Abhilash S. , K. Mohankumar , Sivan C. , Rejoy Rebello , Prabhath H. Kurup

Aspect sensitivity in VHF radar refers to the extent to which the power and spectrum width of echoes vary with changes in the zenith angle, which is related to the backscattering process. The scattering of clear air signals is primarily caused by Fresnel reflection, anisotropic scattering, and isotropic scattering. The aspect sensitivity and accuracy of moment and wind estimation in clear air radars are influenced by the beam width, beam pointing angle from zenith, and atmospheric conditions. This study proposes a method to determine the sensitivity of the recently developed Stratosphere–Troposphere (ST) wind profile Radar in Cochin, India (10.04°N, 76.33°E). The radar operates at a distinct frequency of 205 MHz in the far VHF band. The experiment is conducted at an altitude of 5 to 20 km above the ground by adjusting the beam’s orientation with a resolution of 2°in both the east–west and north-south directions. The estimation of wind components is subject to uncertainty due to the varying aspect angles caused by the distinct dispersion properties in this height range. The study found that power variance is lowest between 6 and 12 km in both north-south and east–west directions, while daily fluctuations in aspect-sensitive echoes complicate wind component estimation. Correlation length (

ζ

) ranges from 0.5 to 15 m, indicating various air scattering processes. Notably,

θ_{s}

is smaller near the zenith and increases with tilt angles, exceeding 20°up to 14 km before declining at higher altitudes, indicating significant anisotropy at elevated levels. The wide range of R factor values (0.1 to 0.9) across different heights causes significant ambiguity in wind estimation. In this study, the impact of various aspect sensitivity parameters on wind estimation on days with clear air has been analyzed.

甚高频雷达的频谱灵敏度是指回波的功率和频谱宽度随天顶角变化而变化的程度，这与后向散射过程有关。晴空信号的散射主要由菲涅尔反射、各向异性散射和各向同性散射引起。晴空雷达的方位灵敏度和时刻及风估算精度受波束宽度、波束与天顶的指向角和大气条件的影响。本研究提出了一种方法来确定最近在印度科钦（北纬 10.04°，东经 76.33°）开发的平流层-对流层（ST）风廓线雷达的灵敏度。该雷达的工作频率为 205 兆赫，属于远甚高频波段。实验在离地面 5 至 20 千米的高度进行，通过调整波束的方向，东西和南北方向的分辨率均为 2°。在这一高度范围内，由于不同的频散特性造成了不同的纵横角，因此对风分量的估算存在不确定性。研究发现，南北向和东西向 6 至 12 千米范围内的功率方差最小，而纵横向敏感回波的日波动使风分量估算复杂化。相关长度（ζ）从 0.5 米到 15 米不等，表明存在各种空气散射过程。值得注意的是，θs 在天顶附近较小，并随倾斜角的增大而增大，在 14 千米以内超过 20°，然后在更高的高度下降，这表明在高空有明显的各向异性。不同高度的 R 因子值范围很广（0.1 至 0.9），导致风力估算非常模糊。在这项研究中，分析了各种高程灵敏度参数对晴朗天气风力估算的影响。

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引用次数: 0

Differential responses of total ozone content to solar activity parameters at two Saudi Arabian locations 沙特阿拉伯两地臭氧总量对太阳活动参数的不同反应

IF 1.8 4区地球科学 Q3 GEOCHEMISTRY & GEOPHYSICS

Journal of Atmospheric and Solar-Terrestrial Physics

Pub Date : 2024-10-18 DOI: 10.1016/j.jastp.2024.106379

Abdullrahman Maghrabi, Mayson Alghamdi

This study examines the correlations between Total Ozone Content (TOC) at two locations in Saudi Arabia—Abha and Jeddah—and various solar activity indicators (sunspot numbers, solar radio flux) and cosmic rays, using data spanning from 1979 to 2023. The research employs correlation analyses and spectral techniques, such as Fast Fourier Transform and wavelet analysis, to explore these relationships.

The results reveal significant non-zero correlations between changes in TOC at both Saudi sites and the studied solar activity indicators and cosmic rays, with these correlations varying in strength and significance across different solar cycles and seasons.

Spectral analysis suggests the presence of several periodicities in the TOC data from both sites, including cycles of 3.9 years, 2.63 years, 1.65 years, 1.1–1.2 years, 325 days (∼0.88 years), 285–293 days (∼0.78–0.80 years), 273 days (∼0.75 years), 249-232 days (∼0.68 years), and 202-188 days (∼0.52 years). Notable shared periodicities between TOC and solar activity and cosmic rays data include ∼2.6 years, 3.8–3.9 years, 1.56 years, 325 days, 273 days, and 166 days.

The findings from both correlation and spectral analyses suggest a potential connection between variations in TOC and solar activity at the specific locations studied. This aligns with previous research indicating that increased UV radiation during periods of high solar activity enhances ozone production, particularly at lower latitudes, and that increased magnetic activity reduces the influx of cosmic rays into the heliosphere, impacting atmospheric ionization.

本研究利用从 1979 年到 2023 年的数据，研究了沙特阿拉伯两个地点--阿布哈和吉达--的臭氧总含量（TOC）与各种太阳活动指标（太阳黑子数、太阳射电通量）和宇宙射线之间的相关性。研究采用了相关性分析和光谱技术（如快速傅立叶变换和小波分析）来探索这些关系。研究结果表明，沙特两个站点的总有机碳变化与所研究的太阳活动指标和宇宙射线之间存在显著的非零相关性，这些相关性在不同太阳周期和季节的强度和重要性各不相同。频谱分析表明，两个观测点的 TOC 数据存在若干周期性变化，包括 3.9 年、2.63 年、1.65 年、1.1-1.2年、325天（∼0.88年）、285-293天（∼0.78-0.80年）、273天（∼0.75年）、249-232天（∼0.68年）和202-188天（∼0.52年）。TOC与太阳活动和宇宙射线数据之间显著的共同周期包括：2.6年、3.8-3.9年、1.56年、325天、273天和166天。这与之前的研究结果一致，即太阳活动频繁时紫外线辐射增加会促进臭氧生成，尤其是在低纬度地区；磁活动增加会减少宇宙射线流入日光层，从而影响大气电离。

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引用次数: 0

Electron-ion model of ball and bead lightning 球状和珠状闪电的电子-离子模型

IF 1.8 4区地球科学 Q3 GEOCHEMISTRY & GEOPHYSICS

Journal of Atmospheric and Solar-Terrestrial Physics

Pub Date : 2024-10-17 DOI: 10.1016/j.jastp.2024.106374

Sergey G. Fedosin

Based on the electron-ion model, parameters of ball and bead lightning are calculated. The model allows us to estimate maximum size of ball lightning, its energy content, electric charge and magnetic field, to determine equilibrium conditions between positively charged ions located inside and outer shell containing rapidly moving electrons. An explanation is given to the fact that shells are observed inside ball lightning that differ from each other in color of glow. The model describes structure of not only ball lightning, but also bead lightning. The long-term stability of bead lightning is associated with the balance of neighboring beads under action of magnetic force of their attraction and electric force of repulsion, which exceed in magnitude the force of wind pressure.

根据电子-离子模型，计算了球状闪电和珠状闪电的参数。通过该模型，我们可以估算球状闪电的最大尺寸、能量含量、电荷和磁场，确定位于内部的带正电离子与包含快速移动电子的外壳之间的平衡条件。该模型解释了为什么在球状闪电内部会观察到不同颜色的外壳。该模型不仅描述了球状闪电的结构，还描述了珠状闪电的结构。珠状闪电的长期稳定性与相邻珠子在磁力吸引和电力排斥作用下的平衡有关，而磁力和电力排斥的大小超过了风压的力量。

引用次数: 0

Construction of global IGS-3D electron density (Ne) model by deep learning 通过深度学习构建全球 IGS-3D 电子密度（Ne）模型

IF 1.8 4区地球科学 Q3 GEOCHEMISTRY & GEOPHYSICS

Journal of Atmospheric and Solar-Terrestrial Physics

Pub Date : 2024-10-16 DOI: 10.1016/j.jastp.2024.106370

Eun-Young Ji , Yong-Jae Moon , Young-Sil Kwak , Kangwoo Yi , Jeong-Heon Kim

In this study, we construct a global IGS-3D N_e model that generates global 3-D electron density (N_e) from International Global Navigation Satellite Systems (GNSS) Service (IGS) total electron content (TEC) data through deep learning. As a first step towards this, we make a model to generate a vertical electron density profile from a TEC value using Multi-Layer Perceptron (MLP). In this process, we use the vertical electron density profiles and the corresponding TEC values of the IRI-2016 model from 2001 to 2008 for training, 2009 and 2014 for validation, and 2010 to 2013 for a test. The next step is to generate global IGS electron density profiles using the global IGS TECs as input data for the model, which is called the global IGS-3D N_e model. We evaluate the IGS-3D N_e model by comparing the electron density profiles from the incoherent scatter radars (ISRs) at three stations with the IGS-3D N_e model from 2010 to 2013. The evaluation shows that the electron density profiles from the IGS-3D N_e model are closer to the ISR data than those of the IRI model, especially at high latitudes. The IGS-3D N_e model shows that the averaged root mean square error (RMSE) values between IGS and ISR electron density profiles are 0.37 log(m⁻³), 0.22 log(m⁻³), and 0.34 log(m⁻³) for all test datasets at Jicamarca, Millstone Hill, and EISCAT stations, respectively. These results suggest that our method has sufficient potential to enhance the ability to predict global electron density profiles.

在本研究中，我们构建了一个全球 IGS-3D Ne 模型，通过深度学习从国际全球导航卫星系统（GNSS）服务（IGS）总电子含量（TEC）数据生成全球三维电子密度（Ne）。作为实现这一目标的第一步，我们利用多层感知器（MLP）建立了一个模型，从 TEC 值生成垂直电子密度剖面。在此过程中，我们使用 2001 年至 2008 年 IRI-2016 模型的垂直电子密度剖面和相应的 TEC 值作为训练，2009 年和 2014 年作为验证，2010 年至 2013 年作为测试。下一步是利用全球IGS TEC值作为模型的输入数据，生成全球IGS电子密度剖面，这就是全球IGS-3D Ne模型。我们通过比较2010年至2013年三个站点非相干散射雷达（ISR）的电子密度剖面与IGS-3D Ne模型，对IGS-3D Ne模型进行了评估。评估结果表明，IGS-3D Ne模式的电子密度剖面比IRI模式更接近ISR数据，尤其是在高纬度地区。IGS-3D Ne模型显示，在Jicamarca、Millstone Hill和EISCAT站点的所有测试数据集上，IGS和ISR电子密度剖面的平均均方根误差（RMSE）值分别为0.37 log(m-3)、0.22 log(m-3)和0.34 log(m-3)。这些结果表明，我们的方法有足够的潜力来提高预测全球电子密度剖面的能力。

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引用次数: 0

Mediaeval Korean aurora and flood records and solar activity cycle of ∼200 yr 韩国中世纪的极光和洪水记录与 200 年的太阳活动周期

IF 1.8 4区地球科学 Q3 GEOCHEMISTRY & GEOPHYSICS

Journal of Atmospheric and Solar-Terrestrial Physics

Pub Date : 2024-10-16 DOI: 10.1016/j.jastp.2024.106373

Kim Jik Su , Kim Chol Jun , Kim Jong Myong

Previous investigation of mediaeval Korean naked-eye sunspot observations has shown the existence of the solar activity cycle of ∼200yr. We examined other mediaeval Korean records of auroral phenomena and floods, and reconfirm the long-term periodicity of ∼200yr. This finding, together with the result of naked-eye sunspot records investigation allows us to confirm again the evidence of the long-term cycle ∼200yr in solar activity.

以前对韩国中世纪裸眼太阳黑子观测的研究表明，太阳活动周期为 200 年。我们研究了韩国中世纪有关极光现象和洪水的其他记录，再次确认了 200 年的长期周期性。这一发现，加上裸眼太阳黑子记录的调查结果，使我们能够再次确认太阳活动的长期周期为 ∼200 年。

引用次数: 0

Spatio-temporal characteristics of rainfall and drought conditions are using the different drought indices with geospatial approaches in Karnataka state 在卡纳塔克邦利用不同的干旱指数和地理空间方法分析降雨和干旱状况的时空特征

IF 1.8 4区地球科学 Q3 GEOCHEMISTRY & GEOPHYSICS

Journal of Atmospheric and Solar-Terrestrial Physics

Pub Date : 2024-10-16 DOI: 10.1016/j.jastp.2024.106372

Harishnaika N, Arpitha M, S.A Ahmed

Karnataka state drought conditions are assessed via drought indices. Over the past several decades, several indices of drought (DI) have been developed and presented, although some of them are region-specific and have problems regarding their applicability to other climatic circumstances. Additionally, choosing the best DI time step to illustrate the drought condition is difficult because of the DIs' various time steps. The study compares the Standardized Precipitation Index (SPI), Statistical Z-Score, China Z-Index (CZI), Rainfall Anomaly Index (RAI), and Rainfall Departure (RD) to determine which one is most appropriate for the districts of the Karnataka state that are prone to both dry and rainy conditions. This study has pointed out that the best drought indices are SPI and RD, and the least accountable drought indice is China Z index. Droughts were most common in 22 districts in 2009, which represent around 70.97% of the state's landmass. In comparison with the rest of the districts, the Ramanagara district noticed the worst drought conditions in 2003, with rainfall reaching 92.47 mm and SPI -3.68, RAI-6.04, MCZI -2.39, and Z score −2.62. Overall, the results of the study will aid in the organization and improvement of drought, flood, agriculture, and water resource management approaches in the state.

卡纳塔克邦的干旱状况是通过干旱指数来评估的。在过去的几十年中，已经开发并提出了多个干旱指数（DI），但其中一些是针对特定地区的，在适用于其他气候条件方面存在问题。此外，由于 DIs 的时间步长各不相同，因此很难选择最佳的 DI 时间步长来说明干旱状况。本研究比较了标准化降水指数 (SPI)、统计 Z 值、中国 Z 指数 (CZI)、降雨异常指数 (RAI) 和降雨离差 (RD)，以确定哪种指数最适合卡纳塔克邦既干旱又多雨的地区。这项研究指出，最好的干旱指数是 SPI 和 RD，最不可靠的干旱指数是中国 Z 指数。2009 年，22 个县的干旱最为普遍，约占该邦国土面积的 70.97%。与其他地区相比，拉马纳加拉地区在 2003 年的旱情最为严重，降雨量达到 92.47 毫米，SPI 为-3.68，RAI 为-6.04，MCZI 为-2.39，Z 指数为-2.62。总之，研究结果将有助于组织和改进该州的干旱、洪水、农业和水资源管理方法。

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引用次数: 0

Identification of the Driving factors impacts of Land Surface Albedo over Iran: An analysis with the MODIS data 确定影响伊朗陆地表面反照率的驱动因素：利用 MODIS 数据进行分析

IF 1.8 4区地球科学 Q3 GEOCHEMISTRY & GEOPHYSICS

Journal of Atmospheric and Solar-Terrestrial Physics

Pub Date : 2024-10-15 DOI: 10.1016/j.jastp.2024.106378

Omid Reza Kefayat Motlagh, Mohammad Darand

Albedo is a key parameter in climatic research and depends on environmental and climatic factors. Modeling these factors greatly contributes to understanding environmental variations. To this end, the data of Land Surface Albedo, Land Surface Temperature (LST), Vegetation, Snow, Elevation, Slope, and Aspect of the MODIS sensor from 1/1/2001 to 30/12/2021 with a 1000-m spatial resolution were used. After pre-processing, monthly, seasonal, and annual albedo modeling was performed using multiple linear regression (MLR) in the highlands of Iran. The results of monthly modeling revealed the salient direct role of snow on the albedo of Iran's highlands in all months, except for July, August, and September. In these months, due to the lack of snow coverage and the fruiting of agricultural lands and gardens, the inverse role of vegetation on albedo variations is determining. Seasonal examinations also showed that snow plays a significant role on the albedo of Iran's highlands in winter, spring, and fall; however, vegetation has a determining role in the summer. The annual results indicated that snow, vegetation, elevation, slope, LST, and aspect, respectively, are the factors affecting albedo in the highlands of Iran. Furthermore, the role of snow, LST, and aspect is positive, while the role of vegetation, elevation, and slope is negative on albedo.

反照率是气候研究中的一个关键参数，取决于环境和气候因素。建立这些因素的模型大大有助于了解环境变化。为此，我们使用了 MODIS 传感器从 2001 年 1 月 1 日至 2021 年 12 月 30 日空间分辨率为 1000 米的地表反照率、地表温度、植被、积雪、海拔、坡度和朝向数据。经过预处理后，使用多元线性回归（MLR）对伊朗高原进行了月度、季节和年度反照率建模。月度模型的结果显示，除七月、八月和九月外，雪对伊朗高原所有月份的反照率都有显著的直接影响。在这几个月里，由于积雪覆盖面积不足，加上农田和花园正在开花结果，植被对反照率变化的反向作用是决定性的。季节性研究还表明，在冬季、春季和秋季，积雪对伊朗高原的反照率起着重要作用；但在夏季，植被起着决定性作用。年度结果表明，积雪、植被、海拔、坡度、LST 和地势分别是影响伊朗高原反照率的因素。此外，积雪、低海拔气温和相向对反照率的影响是积极的，而植被、海拔和坡度对反照率的影响是消极的。

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引用次数: 0

A comprehensive analysis of factors affecting GNSS observation noise 全面分析影响全球导航卫星系统观测噪声的因素

IF 1.8 4区地球科学 Q3 GEOCHEMISTRY & GEOPHYSICS

Journal of Atmospheric and Solar-Terrestrial Physics

Pub Date : 2024-10-12 DOI: 10.1016/j.jastp.2024.106371

Shengyue Ji , Yan Zong , Duojie Weng , Wu Chen , Zhenjie Wang , Kaifei He

Observation noise is one of the most significant error sources in the Global Navigation Satellite System (GNSS). It can be influenced by various factors. Analyzing these factors is crucial for developing a stochastic model for GNSS navigation and positioning. This process ensures that the statistical properties of the observational data are accurately characterized, leading to more reliable and precise positioning results. Previous research has predominantly focused on code type and PPP techniques, often limited by the inability to separately assess observation types across different frequency bands due to ionospheric delay. If based on short baseline, these studies were generally constrained by limited experimental data. This study provides a detailed analysis of the affecting factor on observation noise, including elevation, SNR (signal-to-noise ratio), different receiver and antenna type, different GNSS system, and different frequency bands etc. In addition, environmental effects on observation noise are investigated by comparison between short baseline and zero baseline.

观测噪声是全球导航卫星系统（GNSS）中最重要的误差源之一。它可能受到各种因素的影响。分析这些因素对于开发 GNSS 导航和定位随机模型至关重要。这一过程可确保观测数据的统计特性得到准确描述，从而获得更可靠、更精确的定位结果。以往的研究主要集中在代码类型和 PPP 技术上，但往往受限于电离层延迟而无法分别评估不同频段的观测类型。如果基于短基线，这些研究通常会受到有限实验数据的限制。本研究详细分析了观测噪声的影响因素，包括海拔高度、SNR（信噪比）、不同接收器和天线类型、不同 GNSS 系统和不同频段等。此外，还通过比较短基线和零基线，研究了环境对观测噪声的影响。

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引用次数: 0