Journal of Atmospheric and Solar-Terrestrial Physics最新文献_第9页

Evaluation of meteorological drought indices using remote sensing 气象干旱指数的遥感评价

IF 1.8 4区地球科学 Q3 GEOCHEMISTRY & GEOPHYSICS

Journal of Atmospheric and Solar-Terrestrial Physics

Pub Date : 2024-11-24 DOI: 10.1016/j.jastp.2024.106387

Mojgan Ahmadi , Hadi Ramezani Etedali , Abbass Kaviani , Alireza Tavakoli

Drought indices are a suitable tool for management measures and dealing with drought and are widely used worldwide. One of the most important stages of assessing the drought situation in each region is determining the drought indices to analyze the intensity and duration of drought in that region. The drought index is actually a function of various environmental factors that affect the drought phenomenon. In this study, the drought indices of the standardized precipitation index (SPI), China-Z index (CZI), Z Score Index (ZSI), and modified CZI (MCZI) in different month time scales (1, 3, 6, 9, 12, 18, 24 and 48) and the present of normal index (PNI) in different monthly, seasonally and yearly time scales in Kurdistan Province (stations Saqqez, Qorveh, Bijar, Sanandaj) were evaluated. Global land data assimilation system (GLDAS), Climatic Research Unit (CRU) dataset, and Tropical Rainfall Measuring Mission (TRMM) precipitation data (2000-2020) and TRMM precipitation (2000-2019) were received, and the drought indices were calculated. Root mean square error (RMSE), maximum error (ME), Pearson, and Spearman correlation coefficients were used for evaluation. The results of the SPI index showed that there is a significant relationship between TRMM, CRU, and GLDAS at the Saqqez, Qorveh, and Sanandaj stations (at the 5% level), and there was no significant relationship for TRMM at Bijar station for the 24-month time scale. The correlation coefficient results for the Saqqez and Sanandaj stations in time scales of 1 to 9 months for the SPI, CZI, ZSI, and MCZI indices were better than those of the Bijar and Qorveh stations. In assessing the SPI and CZI drought indices, the highest RMSE was for GLDAS at Bijar station and for the 48-month time scale. In general, the results showed that the drought indices of the SPI, CZI, ZSI, MCZI, and PNI obtained from the TRMM satellite, CRU dataset, and GLDAS model have a good correlation with the drought indices of synoptic stations.

干旱指数是一种适宜的管理措施和应对干旱的工具，在世界范围内得到广泛应用。评估各区域干旱状况最重要的阶段之一是确定干旱指数，以分析该区域干旱的强度和持续时间。干旱指数实际上是影响干旱现象的各种环境因子的函数。本文对库尔德斯坦省（Saqqez、Qorveh、Bijar、Sanandaj站）不同月份（1、3、6、9、12、18、24和48）的标准化降水指数（SPI）、China-Z指数（CZI）、Z Score指数（ZSI）和修正CZI （MCZI）干旱指数和正常指数（PNI）在不同月份、季节和年时间尺度上的变化进行了评价。利用全球陆地数据同化系统（GLDAS）、气候研究单位（CRU）数据集和热带降雨测量任务（TRMM） 2000-2020年降水数据和TRMM 2000-2019年降水数据，计算干旱指数。采用均方根误差（RMSE）、最大误差（ME）、Pearson和Spearman相关系数进行评价。SPI指数结果表明，在Saqqez、Qorveh和Sanandaj站的TRMM、CRU和GLDAS在5%的水平上存在显著相关，而Bijar站的TRMM在24个月的时间尺度上不存在显著相关。在1 ~ 9个月的时间尺度上，Saqqez和Sanandaj站点的SPI、CZI、ZSI和MCZI指数的相关系数结果优于Bijar和Qorveh站点。在SPI和CZI干旱指数评估中，比贾尔站GLDAS和48个月时间尺度的RMSE最高。总体而言，TRMM卫星、CRU数据集和GLDAS模型获得的SPI、CZI、ZSI、MCZI和PNI干旱指数与天气站的干旱指数具有较好的相关性。

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引用次数: 0

Simulation and projection of photovoltaic energy potential over a tropical region using CMIP6 models 利用 CMIP6 模型模拟和预测热带地区的光伏能源潜力

IF 1.8 4区地球科学 Q3 GEOCHEMISTRY & GEOPHYSICS

Journal of Atmospheric and Solar-Terrestrial Physics

Pub Date : 2024-11-20 DOI: 10.1016/j.jastp.2024.106384

Olusola Samuel Ojo, Promise Dunsin Adesemoye

The study examines the potential impact of climate change on photovoltaic energy (PV) in Nigeria. Solar radiation and temperature datasets from 13 regional climate models (CMIP6) for 2015–2099 were used to evaluate the photovoltaic energy under moderate (SSP245) and high (SSP585) emission scenarios for near-future (2023–2053), mid-future (2054–2084), and far-future (2084–2099) periods. The precision of the models for the simulation of PV energy was validated with MERRA-2 reference data using the compromise programming index (CPI). Models with the lowest CPI were selected for regional PV energy projections. The findings showed varying numbers of increase and decrease projected changes across the four regions under SSP245 and SSP585 scenarios for the near, mid and far future timescales. Specifically, in the SSP245 scenario, the model with lowest CPI was the CMCC-CESM2 model, it projected a decrease in PV energy in the Sahel (−2.30), an increase in the Guinea Savannah (+2.80), the Rainforest (+1.20) and the coastal region (+4.80) for the far future period (2085–2099). In the SSP585 scenario, the AWI-CM-1.1-MR model projected a decrease in the Sahel region (−4.60), while the MPI-ESM1-2-LR model projected an increase in the Guinea Savannah region (+1.80), and the ACCESS-CM2 model projected an increase in the Rainforest (+10.20) and Coastal regions (+13.20) for the far-future. All values in the parentheses are measured in watts-hour per square-meters. The projected changes in PV energy revealed the need for a regional-specific approach to the planning and implementation of energy transition mix in Nigeria.

本研究探讨了气候变化对尼日利亚光伏能源（PV）的潜在影响。研究使用了 13 个区域气候模型（CMIP6）中 2015-2099 年的太阳辐射和温度数据集，以评估近未来（2023-2053 年）、中未来（2054-2084 年）和远未来（2084-2099 年）期间中度（SSP245）和高度（SSP585）排放情景下的光伏能源。利用折衷编程指数（CPI），通过 MERRA-2 参考数据验证了光伏能源模拟模型的精度。选择 CPI 最低的模型进行区域光伏能源预测。研究结果表明，在 SSP245 和 SSP585 情景下，四个地区在近期、中期和远期时间尺度上的预测增减变化数量各不相同。具体而言，在 SSP245 情景中，CPI 最低的模型是 CMCC-CESM2 模型，该模型预测萨赫勒地区的光伏发电量将减少（-2.30），几内亚大草原（+2.80）、热带雨林（+1.20）和沿海地区（+4.80）的光伏发电量在远期（2085-2099）将增加。在 SSP585 情景下，AWI-CM-1.1-MR 模式预测萨赫勒地区将减少（-4.60），而 MPI-ESM1-2-LR 模式预测几内亚大草原地区将增加（+1.80），ACCESS-CM2 模式预测远未来热带雨林地区将增加（+10.20），沿海地区将增加（+13.20）。括号中的所有数值均以每平方米瓦时为单位。光伏能源的预测变化表明，在尼日利亚规划和实施能源转型组合时，需要采用针对具体地区的方法。

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引用次数: 0

Variability of ENSO teleconnections indices, and its impacts on moroccan agriculture 厄尔尼诺/南方涛动远程联系指数的变化及其对摩洛哥农业的影响

IF 1.8 4区地球科学 Q3 GEOCHEMISTRY & GEOPHYSICS

Journal of Atmospheric and Solar-Terrestrial Physics

Pub Date : 2024-11-15 DOI: 10.1016/j.jastp.2024.106386

Sujatha Peethani , Mahesh Pathakoti , Mahalakshmi D. V , Ahmed MS. Kheir , Apoorva Singh , Ajit Govind

In Morocco, drought periods have become more frequent and severe due to climate change, which has had a substantial effect on freshwater supply and agricultural output. The El Niño-Southern Oscillation (ENSO) and the influence of climatic variability were the main subjects of the current study, which made use of daily precipitation, maximum and minimum temperature data collected at 50 locations around the nation from 1990 to 2022. The study analysed Palmer Drought Severity Index (PDSI) over Morocco to evaluate the impact of climate indices such as the Oceanic Niño Index (ONI) and the North Atlantic Oscillation (NAO) on drought severity. It also investigated the changes in precipitation, temperature, and extreme event-related indices. Rainfall is used as a proxy for El Nino and La Nina, supported by a negative and significant correlation between Oceanic Nino Index (ONI) and rainfall. Attempted to understand the impact of the NAO on Morocco's agricultural production, particularly during the winter months. During negative NAO phases, winter temperatures can lead to reduced wheat yields by 35–45% during the El Niño years and decreased by 4–7% during the La Niña years compared to the actual yield. Relying on the NAO plays a crucial role in modulating the precipitation patterns, which implies that crop requires adequate soil moisture with no extreme temperature during the growing season in order to produce higher yield. ENSO events can indeed lead to these extreme conditions in selected locations, potentially impacting crop yields.

在摩洛哥，由于气候变化，干旱期变得更加频繁和严重，这对淡水供应和农业产出产生了重大影响。厄尔尼诺-南方涛动（ENSO）和气候多变性的影响是本次研究的主要课题，研究利用了 1990 年至 2022 年期间在全国 50 个地点收集的日降水量、最高气温和最低气温数据。研究分析了摩洛哥的帕尔默干旱严重程度指数（PDSI），以评估海洋尼诺指数（ONI）和北大西洋涛动（NAO）等气候指数对干旱严重程度的影响。研究还调查了降水、温度和极端事件相关指数的变化。降雨量被用作厄尔尼诺和拉尼娜的代用指标，海洋尼诺指数（ONI）与降雨量之间存在显著的负相关关系。试图了解西北气旋对摩洛哥农业生产的影响，尤其是在冬季。与实际产量相比，在厄尔尼诺年，冬季气温会导致小麦减产 35-45%，而在拉尼娜年则会减产 4-7%。在调节降水模式方面，NAO 起着至关重要的作用，这意味着作物在生长季节需要充足的土壤水分，且没有极端温度，才能获得更高的产量。厄尔尼诺/南方涛动事件确实会导致某些地区出现这种极端情况，从而可能影响作物产量。

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引用次数: 0

Development of Land Use Regression (LUR) models and high-resolution spatial mapping of criteria air pollutants: Leveraging Delhi's continuous air monitoring network and remote sensing data 开发土地利用回归（LUR）模型和高分辨率标准空气污染物空间分布图：利用德里的连续空气监测网络和遥感数据

IF 1.8 4区地球科学 Q3 GEOCHEMISTRY & GEOPHYSICS

Journal of Atmospheric and Solar-Terrestrial Physics

Pub Date : 2024-11-15 DOI: 10.1016/j.jastp.2024.106385

Pratyush Agrawal , Adithi R. Upadhya , Srishti S , Mahesh Kalshetty , Padmavati Kulkarni , Meenakshi Kushwaha , V. Sreekanth

High-resolution air pollution maps can help researchers and governments better characterize and mitigate pollution levels in a given region. Land Use Regression (LUR) modeling is a statistical approach capable of predicting pollution levels at a high spatial resolution. In this study, we used pollution data (for the calendar year 2019) from a dense (compared to other Indian regions) regulatory monitoring network in Delhi, India, to develop simple linear and interpretable LUR models for various criteria pollutants. The observed annual mean PM_2.5 and PM₁₀ over Delhi were found to be ∼110 μg m⁻³ and 220 μg m⁻³, respectively. The PM concentration levels were 2.5–4 times higher than the prescribed national ambient standards, while the gaseous criteria pollutants were found to be within the standards (over most of the study area). The performance of the developed LUR models ranged from poor to moderate levels (adjusted-R² values of the models were between 0.14 and 0.63). Land use and road-network related variables were found to be the most common predictors of the observed pollution levels. Moderately performing models (11 out of the developed 20) were then used to predict pollution levels at 50 m spatial intervals and to identify the most polluted districts. The advantages and limitations of using the existing regulatory network data for LUR development, and the other probable potential reasons responsible for the underperformance of the developed models are extensively discussed. To our knowledge, this is one of the few studies carried over Indian region to develop LUR models utilizing regulatory monitoring network data.

高分辨率空气污染地图可以帮助研究人员和政府更好地描述和减轻特定区域的污染水平。土地利用回归（LUR）建模是一种能够预测高空间分辨率污染水平的统计方法。在本研究中，我们利用印度德里密集（与印度其他地区相比）的监管监测网络提供的污染数据（2019 年），为各种标准污染物建立了简单的线性和可解释的 LUR 模型。在德里观测到的 PM2.5 和 PM10 年平均值分别为 110 μg m-3 和 220 μg m-3。可吸入颗粒物的浓度水平比国家规定的环境标准高出 2.5-4 倍，而气态标准污染物则在标准范围之内（在大部分研究区域）。所开发的 LUR 模型的性能从较差到中等水平不等（模型的调整 R2 值介于 0.14 和 0.63 之间）。研究发现，土地利用和道路网络相关变量是观测到的污染水平最常见的预测因素。然后，利用性能中等的模型（20 个已开发模型中的 11 个）来预测 50 米空间间隔的污染水平，并确定污染最严重的地区。我们广泛讨论了使用现有监管网络数据开发 LUR 的优势和局限性，以及导致所开发模型表现不佳的其他潜在原因。据我们所知，这是印度地区利用监管监测网络数据开发 LUR 模型的少数研究之一。

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引用次数: 0

Characterization of gravity wave events detected in the low ionosphere at the Brazilian Antarctic Station 巴西南极站低电离层探测到的重力波事件的特征

IF 1.8 4区地球科学 Q3 GEOCHEMISTRY & GEOPHYSICS

Journal of Atmospheric and Solar-Terrestrial Physics

Pub Date : 2024-11-10 DOI: 10.1016/j.jastp.2024.106383

Luís Tiago Medeiros Raunheitte , Emilia Correia , Jean Pierre Raulin , José Valentin Bageston

Here we present the characteristics of three distinct types of Gravity Wave (GW) events as detected in the low ionosphere using very low frequencies (VLF) radio measurements performed at the EACF, Brazilian Antarctic Station Comandante Ferraz (62° 5′ 6″ S, 58° 24′ 12″ W), on King George Island. GWs in the low ionosphere produce oscillations in the electron density, which can be detected as amplitude and phase fluctuations of the VLF signals. The properties of the GW events are obtained using Morlet's Wavelet analysis, which gives the period of the waves, and their occurrence time. The period and duration of the GW events obtained using the VLF technique presented good agreement with ones previously obtained from airglow observations from a co-located all-sky imager. The VLF detection of the mesospheric front showed the same morphology seen with the imager with four crests identified, and the wave activity presented similar period range (∼4–16 min) as observed by airglow (∼6 min) with a period peak of 14 min equal to the spectral analysis of the concurrent OH temperature data. The activity associated with the band event presented similar period of ∼10 min (imager observed 13 min), same duration of 4 h as well as peak intensity just before 05:00 UT. The ripple detection showed the same period of 8 min as the airglow observations and similar duration of around 25 min. By considering two distinct VLF paths it was also possible to analyze the direction and velocity of propagation for the mesospheric front event, which gives 96.0 (±4.8) ms⁻¹ in the East direction in agreement with the velocity of ∼92 ms⁻¹ in the Northeast direction obtained from the airglow observations.

本文介绍了在乔治王岛巴西南极站 Comandante Ferraz（南纬 62°5′6″，西经 58°24′12″）的 EACF，利用甚低频无线电测量在低电离层探测到的三种不同类型的重力波（GW）事件的特征。低电离层中的全球风暴潮会产生电子密度振荡，这可以通过甚低频信号的振幅和相位波动探测到。利用莫雷特小波分析法可获得全球波事件的特性，从而得出波的周期及其发生时间。利用甚低频技术获得的全球瓦事件的周期和持续时间与之前通过同地全天空成像仪观测气辉获得的周期和持续时间非常吻合。对中间层锋面的甚低频探测显示了与成像仪相同的形态，确定了四个波峰，波活动的周期范围（∼4-16 分钟）与气辉观测到的相似（∼6 分钟），周期峰值为 14 分钟，与同期 OH 温度数据的光谱分析结果相同。与波段事件相关的活动呈现出相似的周期（10 分钟）（成像仪观测到的是 13 分钟），持续时间同样为 4 小时，峰值强度就在世界标准时间 05:00 之前。波纹探测显示的周期与气辉观测的周期相同，为 8 分钟，持续时间相似，约为 25 分钟。通过考虑两条不同的甚低频路径，还可以分析出中间层前沿事件的传播方向和速度，东向的传播速度为 96.0（±4.8）毫秒-1，与气辉观测中获得的东北方向的传播速度∼92 毫秒-1 相一致。

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引用次数: 0

Comparative assessment of empirical random forest family's model in simulating future streamflow in different basin of Sarawak, Malaysia 模拟马来西亚沙捞越州不同流域未来河水流量的经验随机森林族模型的比较评估

IF 1.8 4区地球科学 Q3 GEOCHEMISTRY & GEOPHYSICS

Journal of Atmospheric and Solar-Terrestrial Physics

Pub Date : 2024-11-02 DOI: 10.1016/j.jastp.2024.106381

Zulfaqar Sa’adi , Shamsuddin Shahid , Mohammed Sanusi Shiru , Kamal Ahmed , Mahiuddin Alamgir , Mohamad Rajab Houmsi , Lama Nasrallah Houmsi

In Sarawak, a region highly vulnerable to climate change, the translation of climate-induced changes in rainfall to river flow is non-linear, presenting a challenge for water resource managers. This research investigates the impact of climate change on hydrological processes in Sarawak, Malaysia, with a specific focus on assessing future spatiotemporal variations in streamflow. The families of Random Forest (RF) empirical models based on data mining techniques were compared and utilized to develop a continuous hydrologic model. Then, by incorporating rainfall and evapotranspiration future projection prepared based on RF past performance statistical downscaling, the top performing RF empirical hydrological model was used for future streamflow projection. The results showed that despite an expected increase in rainfall, the RFR (Random Forest by Randomization) empirical hydrological model demonstrated a potential decrease in river runoff due to heightened evapotranspiration demands associated with rising temperatures. The examination of climate-induced alterations in both rainfall and evapotranspiration patterns revealed a consistent decrease in river discharges during the early to middle period across Sarawak, followed by a shift towards an increasing trend by the end of the 21st century. The central region along the Rajang basin exhibited a prevailing decrease in river discharge, with contrasting patterns in the last part of the century. The northern region displayed diverse trends, with some basins experiencing decreases in river runoff despite augmented rainfall, emphasizing the heterogeneity in response. By employing empirical models, and projecting future scenarios, the study contributes to a better understanding of climate change impacts on hydrology in the region, essential for effective water resource management and environmental conservation.

在沙捞越这个极易受气候变化影响的地区，由气候引起的降雨量变化对河流流量的影响是非线性的，这给水资源管理者带来了挑战。本研究调查了气候变化对马来西亚沙捞越水文过程的影响，重点是评估未来河流流量的时空变化。研究人员比较了基于数据挖掘技术的随机森林（RF）经验模型系列，并将其用于开发连续水文模型。然后，通过结合基于 RF 过去性能统计降尺度编制的降雨量和蒸散量未来预测，将性能最好的 RF 经验水文模型用于未来溪流预测。结果表明，尽管预计降雨量会增加，但 RFR（随机化随机森林）经验水文模型显示，由于气温升高导致蒸散需求增加，河流径流量可能会减少。对气候引起的降雨和蒸散模式变化的研究表明，沙捞越全境的河流排水量在早中期持续减少，到 21 世纪末则呈上升趋势。拉让盆地沿岸的中部地区的河流排水量普遍减少，在本世纪末出现了截然不同的模式。北部地区呈现出不同的趋势，一些流域尽管降雨量增加，但河流径流量却减少了，这凸显了响应的不一致性。通过采用经验模型和预测未来情景，该研究有助于更好地了解气候变化对该地区水文的影响，这对有效的水资源管理和环境保护至关重要。

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引用次数: 0

Air-sea interactions and Bay of Bengal basin wide variability with respect to long tracked cyclone ‘Viyaru’ 海气相互作用和孟加拉湾海盆大范围变化与长轨迹气旋 "维亚鲁 "有关

IF 1.8 4区地球科学 Q3 GEOCHEMISTRY & GEOPHYSICS

Journal of Atmospheric and Solar-Terrestrial Physics

Pub Date : 2024-11-01 DOI: 10.1016/j.jastp.2024.106382

Gopi Krishna Podapati , Pushpalatha Tadivalasa , Sreenivas Pentakota , Dandi A. Ramu , Sagar V. Gade

The Bay of Bengal (BoB) is a potentially active region for the formation of the Tropical Cyclones (TCs) and accounts for about 6% of the global annual total number of tropical storms. These TCs occur during the pre-monsoon (March–May) and post-monsoon (October–November) seasons over the BoB. Among all the pre-monsoon cyclones that occurred from 1993 to 2019, we have identified that the “Viyaru” is a typical one originated in the southern BoB, propagated approximately through the middle of the bay, and made landfall over the northern BoB. The cyclonic storm Viyaru caused a basin-scale sea surface cooling of 0.35 °C by increasing the mixed layer depth by 3.5 m over the Bay of Bengal. An analysis of mixed layer heat budget terms infers that reduced short wave radiation and increased latent heat fluxes as the key factors responsible for basin-wide cooling associated with the Viyaru cyclone. We have also found that the enhanced entrainment processes even after the dissipation of the Viyaru cyclone had resulted in a post-cyclone basin-wide cooling tendency over the Bay of Bengal. The present study exemplifies the role of a pre-monsoon cyclone (Viyaru) in impacting the Bay of Bengal basin-scale variability of surface Physical Oceanographic variables and associated processes.

孟加拉湾（BoB）是热带气旋（TCs）形成的潜在活跃区域，每年的热带风暴数量约占全球总数的 6%。这些热带气旋多发生在季风前（3 月至 5 月）和季风后（10 月至 11 月）的季节。在 1993 年至 2019 年发生的所有季风前气旋中，我们发现 "维亚鲁 "是一个典型的气旋，它起源于渤海湾南部，大约从渤海湾中部传播，并在渤海湾北部登陆。气旋风暴 "维亚鲁 "使孟加拉湾上空的混合层深度增加了 3.5 米，造成海盆尺度海面降温 0.35 °C。对混合层热量预算项的分析表明，短波辐射的减少和潜热通量的增加是造成与 Viyaru 气旋有关的全海盆降温的关键因素。我们还发现，即使在维亚鲁气旋消散后，增强的夹带过程也导致了气旋后孟加拉湾全海盆降温的趋势。本研究说明了季风前气旋（维亚鲁气旋）在影响孟加拉湾海盆尺度表面物理海洋学变量变化及相关过程方面所起的作用。

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引用次数: 0

Observation of sporadic E layer altitude partially modulated by the Traveling Ionospheric Disturbances at high latitudes over Zhongshan station 在中山站上空观测到部分受高纬度移动电离层扰动调制的零星 E 层高度

IF 1.8 4区地球科学 Q3 GEOCHEMISTRY & GEOPHYSICS

Journal of Atmospheric and Solar-Terrestrial Physics

Pub Date : 2024-10-24 DOI: 10.1016/j.jastp.2024.106377

Alicreance Hiyadutuje , Michael J. Kosch , John Bosco Habarulema , Xiangcai Chen , Judy A.E. Stephenson , Tshimangadzo Merline Matamba , Mpho Tshisaphungo

At Zhongshan (69° S, 76° E) Antarctica we investigate the sporadic

E

(

E s

)-layer virtual height modulation, observed by an ionosonde, during the passage of the Medium-Scale Traveling Ionospheric Disturbances (MSTIDs), observed by a SuperDARN radar. Two events were identified, on 04 October 2011 at 07:00 - 12:00 UT and 29 February 2012 at 00:00 - 04:00 UT with periods of

\sim

15.0 and

\sim

12.0 min, respectively. The magnitude of average height modulation of the

E s

-layer was

\sim

3.7 to

\sim

17.1 and

\sim

0.5 to

\sim

7.3 km, respectively, with the same periods as the MSTIDs. Ray tracing during the events shows that the likely MSTID propagation was up to

\sim

300 km in the ionospheric

F

-region. The computed ion vertical drift velocity using SuperDARN radar and magnetometer data, and

E s

-layer altitude modulation observed by the ionosonde have moderate to strong positive correlation of 0.71 ± 0.22 and 0.51 ± 0.16, respectively. We show that the MSTIDs polarization electric field, which is mapped down from the

F

-region along the near-vertical magnetic field, moderately contributes to the modulation of the

E s

layer altitude via the

E \times B

drift mechanism.

在南极洲中山（南纬 69°，东经 76°），我们调查了电离层虚拟高度调制（由电离层探测仪观测）和中尺度移动电离层扰动（由超级雷达网雷达观测）通过期间的零星情况。确定了两个事件，分别发生在 2011 年 10 月 4 日世界时 07:00 - 12:00 和 2012 年 2 月 29 日世界时 00:00 - 04:00，周期分别为 15.0 分钟和 12.0 分钟。Es层的平均高度调制幅度分别为∼3.7至∼17.1和∼0.5至∼7.3 km，周期与MSTID相同。事件期间的光线跟踪显示，MSTID 在电离层 F 区域的传播可能高达 ∼300 公里。利用 SuperDARN 雷达和磁强计数据计算的离子垂直漂移速度与电离层高度调制观测到的电离层高度调制具有中等到较强的正相关性，分别为 0.71 ± 0.22 和 0.51 ± 0.16。我们的研究表明，MSTIDs极化电场是从F区沿近垂直磁场向下映射的，它通过E×B漂移机制对Es层高度的调制有适度的贡献。

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引用次数: 0

PAOFCDN: A novel method for predictive analysis of solar irradiance PAOFCDN：预测分析太阳辐照度的新方法

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.2024.106376

Sana Mujeeb

Solar photovoltaic power is the most feasible Renewable Energy Source (RES) for Pakistan, due to ample sunlight availability throughout the year. Since solar photovoltaic power is primarily dependent on solar irradiance, forecasting of solar irradiance is essential for reliable, secure and effective incorporation of solar photovoltaic power in power systems. Considering the importance of solar irradiance forecasting, in this study, predictive analysis of Islamabad’s solar irradiance is performed by using a novel proposed model named as Pelican Algorithm-based Optimized Fully-Connected Deep Network (PAOFCDN). The initial weights of Fully-Connected Deep Network (FCDN) are optimized through an effective optimization technique known as Pelican optimization. The accuracy of the optimized network PAOFCDN is enhanced many fold as compared to the FCDN network trained with randomly initialized weights. The inherent issue of poor generalization in FCDN is also resolved by optimization. The superior performance of PAOFCDN is evident from its comparative evaluation with existing benchmark methods, i.e., Long Short-Term Memory (LSTM), Support Vector Regression (SVR), Least Square Boosting (LSBoost) and standard FCDN. PAOFCDN achieves the least Normalized Root Mean Square Error (NRMSE) of 0.0503 as compared to 0.1179 of LSTM, 0.1256 of FCDN, and 0.2992 of SVR and LSBoost. The proposed model is applied to three real-world solar irradiance datasets having different resolutions of 10-minutes, hourly and daily. This study took the initiative of performing predictions on three datasets having multiple resolutions in perspective of south asia.

太阳能光伏发电是巴基斯坦最可行的可再生能源 (RES)，因为巴基斯坦全年都有充足的日照。由于太阳能光伏发电主要依赖于太阳辐照度，因此要将太阳能光伏发电可靠、安全、有效地纳入电力系统，就必须对太阳辐照度进行预测。考虑到太阳辐照度预测的重要性，在本研究中，通过使用一种名为 "基于鹈鹕算法的优化全连接深度网络（PAOFCDN）"的新模型，对伊斯兰堡的太阳辐照度进行了预测分析。全连接深度网络（FCDN）的初始权重是通过一种名为鹈鹕优化的有效优化技术进行优化的。与使用随机初始化权重训练的 FCDN 网络相比，经过优化的 PAOFCDN 网络的准确性提高了许多倍。FCDN 固有的泛化能力差的问题也通过优化得到了解决。PAOFCDN 与现有基准方法（即长短期记忆 (LSTM)、支持向量回归 (SVR)、最小平方提升 (LSBoost) 和标准 FCDN）的比较评估表明，PAOFCDN 性能优越。与 LSTM 的 0.1179、FCDN 的 0.1256 以及 SVR 和 LSBoost 的 0.2992 相比，PAOFCDN 的归一化均方根误差（NRMSE）最小，为 0.0503。提出的模型被应用于三个真实世界的太阳辐照度数据集，这些数据集的分辨率各不相同，分别为 10 分钟、每小时和每天。本研究以南亚地区为视角，对三个具有不同分辨率的数据集进行了预测。

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引用次数: 0

On the low-latitude ionospheric irregularities under geomagnetically active and quiet conditions using NavIC observables: A spectral analysis approach 利用 NavIC 观测数据研究地磁活跃和安静条件下的低纬度电离层不规则性：光谱分析方法

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.2024.106369

Sumanjit Chakraborty , Abhirup Datta

Ionospheric irregularities and associated scintillations under geomagnetically active/quiet conditions have detrimental effects on the reliability and performance of space- and ground-based navigation satellite systems, especially over the low-latitude region. The current work investigates the low-latitude ionospheric irregularities using the phase screen theory and the corresponding temporal Power Spectral Density (PSD) analysis to present an estimate of the outer irregularity scale sizes over these locations. The study uses simultaneous L5 signal C/N

_{o}

observations of NavIC (a set of GEO and GSO navigation satellite systems) near the northern crest of EIA (Indore: 22.52

^{\circ}

N, 75.92

^{\circ}

E, dip: 32.23

^{\circ}

N) and in between the crest and the dip equator (Hyderabad: 17.42

^{\circ}

N, 78.55

^{\circ}

E, dip: 21.69

^{\circ}

N). The study period (2017–2018) covers disturbed and quiet-time conditions in the declining phase of the solar cycle 24. The PSD analysis brings forward the presence of irregularities, of the order of a few hundred meters during weak-to-moderate and quiet-time conditions and up to a few km during the strong event, over both locations. The ROTI values validate the presence of such structures in the Indian region. Furthermore, only for the strong event, a time delay of scintillation occurrence over Indore, with values of 36 min and 50 min for NavIC satellites (PRNs) 5 and 6, respectively, from scintillation occurrence at Hyderabad is observed, suggesting a poleward evolution of irregularity structures. Further observations show a westward propagation of these structures on this day. This study brings forward the advantage of utilizing continuous data from the GEO and GSO satellite systems in understanding the evolution and propagation of the ionospheric irregularities over the low-latitude region.

地磁活跃/安静条件下的电离层不规则现象和相关闪烁对空间和地面导航卫星系统的可靠性和性能有不利影响，特别是在低纬度地区。目前的工作利用相屏理论和相应的时间功率谱密度分析对低纬度电离层不规则现象进行了研究，提出了对这些地点外部不规则现象规模大小的估计。该研究使用了在 EIA 北部波峰附近（印多尔：22.52∘N，75.92∘E，倾角：32.23∘N）和波峰与倾角赤道之间（海得拉巴：17.42∘N，78.55∘E，倾角：21.69∘N）的 NavIC（一组地球同步轨道和地球同步轨道导航卫星系统）的 L5 信号 C/No 同步观测。研究时段（2017-2018 年）涵盖了太阳周期 24 递减阶段的扰动和静止状态。PSD 分析表明，这两个地点存在不规则现象，在弱至中等强度和静止期间为几百米，在强事件期间可达几千米。ROTI 值验证了印度地区存在此类结构。此外，仅在强事件中，NavIC 卫星（PRNs）5 号和 6 号在印多尔上空发生闪烁的时间与海德拉巴发生闪烁的时间分别延迟了 36 分钟和 50 分钟，这表明不规则结构是向极地演化的。进一步的观测表明，这些结构在这一天向西传播。这项研究提出了利用地球同步轨道和地球静止轨道卫星系统的连续数据来了解低纬度地区电离层不规则结构的演变和传播的优势。

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引用次数: 0