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Nº 3 (2025)
ФИЗИЧЕСКИЕ ОСНОВЫ ИССЛЕДОВАНИЯ ЗЕМЛИ ИЗ КОСМОСА
Estimation of the precision of atmospheric phase delay models for displacement fields on Kamchatka region calculated by the differential interferometry method
Resumo
The paper considers various ways of calculating atmospheric phase delays to correct the interferometric phase from which the displacements of the Earth’s surface are calculated by satellite radar interferometry methods. A local empirical weather model based on the empirical dependences of the physical properties of the atmosphere on altitude was constructed using data from Kamchatka meteorological stations, and electromagnetic signal propagation delays were calculated using this model. Further, the precision of the empirical weather model and the GACOS (Generic Atmospheric Corrections Online Service) model was assessed by comparing them with the delays calculated from the network of GNSS sites of the Kamchatka Branch of the Federal Research Center of “United Geophysical Service of RAS” (KB of UGS RAS) in the area of the Kliuchevskoi group of volcanoes. The results showed that for all precision assessment criteria, the GACOS model has lower error and better match with the GNSS data at the result comparison points. The relative residuals of the empirical model delays range from 0 to 5.7%, while for the GACOS delays the relative residuals do not exceed 1.6%. Meanwhile, for the GACOS and empirical weather models, on average, the relative residual is 0.3% and 0.9%, respectively, and the RMS errors are 0.6 cm and 2.3 cm. In general, at points of the locations of GNSS sites, a fairly good precision of calculations was obtained: the error is less than 1%, as well as a very high coefficient of determination of the dependencies of the compared models, almost corresponding to the correlation coefficient equal to 1. In addition, for 25% of the results, it is obtained that the empirical model outperforms the GACOS model, i.e., the delay values are closer to the delays calculated from the measurements at the GNSS sites. Since half of the weather stations and GNSS sites used to calculate the empirical weather model are local stations of the Kamchatka network that are not part of the global networks, the results obtained provide an independent assessment of the precision of corrections from the GACOS online service to the peninsula. The results of the study also show that the empirical atmospheric model constructed in this work provides good precision of calculations at GNSS point locations and their data allow us to calculate atmospheric delays for the Earth surface displacement fields obtained by satellite interferometry methods with high accuracy.
Issledovanie Zemli iz Kosmosa. 2025;(3):3-12
3-12
Comparison of Atmospheric Corrections Models to Satellite Interferometry Data on Kamchatka Region
Resumo
In this paper, a comparative analysis of the results of applying atmospheric corrections to real displacement fields calculated by differential interferometry for the volcanic region of Kamchatka during the active phase of eruptions accompanied by significant changes in the atmospheric composition is carried out. Atmospheric corrections were calculated in two ways: 1) according to phase delay data from the online service GACOS (Generic Atmospheric Corrections Online Service), 2) by delays calculated using an empirical weather model based on data from local meteorological and GNSS stations in Kamchatka. An analysis of the effectiveness of each correction model was carried out and an assessment of their impact on the displacement fields was made. The positive result satisfying the conditions of noise reduction and tropospheric effect decrease was obtained for 74% of interferograms with GACOS correction, and for 48% of interferograms corrected using the empirical weather model. In some cases, the empirical model corrections were more accurate than the GACOS corrections. The analysis of the influence of atmospheric corrections on the displacement field has shown that in some cases the GACOS model introduces changes in the displacement field, forming regions of positive or negative anomalies that have no connection with the original displacement field. The atmospheric correction model, calculated from data of regional local meteorological stations that are not included in the international synoptic list, is useful for supplementing and developing methods for eliminating the atmospheric component of the interferometric phase. The performed study showed that in the Kamchatka region, GACOS models in many cases effectively eliminate atmospheric noise and improve the precision of the estimation of displacement fields. On the other hand, in some cases the corrections may introduce additional noise, so we do not recommend using default corrections without comparing the original and corrected displacement fields, with special attention to analysing the displacements that appeared after the introduction of corrections.
Issledovanie Zemli iz Kosmosa. 2025;(3):13-25
13-25
ИСПОЛЬЗОВАНИЕ КОСМИЧЕСКОЙ ИНФОРМАЦИИ О ЗЕМЛЕ
Estimation of anthropogenic methane emissions for some areas of Siberia based on the ECCAD service and correlation of service data with ground measurements for the Teriberka area
Resumo
Based on the CAMS-GLOB-ANT database of the ECCAD online- service, an estimate of the average annual variations in anthropogenic methane emissions for the Urengoyskoye field and individual coal mines of Kuzbass, Krasnoyarsk Territory, Irkutsk Region and Buryatia for the period 2000-2023 was made. For each grid cell with a size of 0.1°× 0.1°according to the CAMS-GLOB-ANT inventory, information on the volume of CH4leakage per month or year is available. Significant changes in the operation of sites (termination) are tracked by jumps in CH4emissions. A comparison of methane emissions from coal mines with field leaks within the grid cell showed that CH4emissions in coal mines are almost 10 times higher than field leaks. Methane leaks in the field during production and transportation have tended to decrease since 2015. For coal mines, there is a positive trend in methane emissions. A close relationship is shown between ground-based measurements of methane concentration in Teriberka and an estimate of methane emissions based on CAMS-GLOB-ANT inventory data.
Issledovanie Zemli iz Kosmosa. 2025;(3):26-36
26-36
Gross primary production estimation of the Leningrad region ecosystem using OCO-2 datasets
Resumo
In order to implement measures to control climate-active gases and study the absorption potentialof greenhouse gases in Russia began the creation of carbon test sites, each of which is characterized by a representative ecosystem on the territory of our country. One of the goals of the Ladoga carbon test site, planned for creation in 2024–2025 on the territory of the Leningrad Region, is to study the processes of carbon dioxide absorption by the Northwest Russian ecosystem. For this reason, it is necessary to estimate gross primary production (GPP) and understand of the processes influencing on it. GPP for the Leningrad Region territory in 2014–2022 was determined using solar-induced chlorophyll fluorescence (SIF) data measured by the OCO-2 satellite equipment. It was found that GPP has an annual cycle with maximum in June–July. Moreover, GPP trend for 2015–2021 was positive, 0.08 ± 0.02 gCm–2day–1year–1. The estimated values of net ecosystem exchange (NEE) of the Ladoga carbon test site were 0.1–2.3 ktCO2year–1. The obtained results can be used for independent assessments of the absorption potential on the Russian territory.
Issledovanie Zemli iz Kosmosa. 2025;(3):37-46
37-46
Application of multispectral Landsat and resource-P space survey for forecasting diamond bearing kimberlites in the Arkhangelsk and Vologda regions of Russia.
Resumo
A comprehensive study of space and geological-geophysical survey materials was performed to predict diamond-bearing kimberlites in the Arkhangelsk and Vologda regions of Russia. New methods of computer processing of multispectral space survey materials were developed to identify diamond-promising areas in areas covered by a cover of Quaternary and Middle Carboniferous deposits. The important role of high-resolution space survey Resurs-P for studying local structures that control the placement of kimberlite pipes is shown.
Issledovanie Zemli iz Kosmosa. 2025;(3):47-71
47-71
Mean Circulation of the Japan Sea from Drifter Data and Satellite Altimetry Observations
Resumo
Knowledge of long-term mean by highly variable currents is essential to understanding the regional climate change in the Japan Sea. Strength and location of the major currents can be identified from the subsurface drifter observation (Global Drifter Program, 1988-2023) and surface absolute geostrophic current field (AVISO satellite altimetry, 1993-2022). The well-known circulation patterns are observed, as the Tsushima Warm Current (TWC), the East-Korean Warm Current (EKWC), the Primorye (Liman) Current, Subpolar Front Current, and the northern cyclonic gyre. A detailed analysis of the surface current field showed that the EKWC in the western part of the Sea of Japan forms three anticyclonic meanders. The well pronounced eastern meander (branch) of this current is observed in the Ulleung Basin. The second meander is formed due to flow separation from the coast in the area of East Korea Bay. The third meander is observed in the northwestern part of the Sea of Japan. The Primorye Current breaks away from the coast of Primorye in the area of Peter the Great Bay and follows to the Subpolar front.. The interaction of the Primorye Current with the northwestern meander of the EKWC leads to the formation of the northwestern dynamic front. Our analyses revealed that the TWC is divided into the nearshore (coastal) branch and three branches of offshore TWC. Formation of the Subpolar Front Current in the western part of the sea is determined by the waters of the ECWT. The Primorye Current affects the northern dynamic boundary of this frontal zone. In the central and eastern parts of the Sea of Japan, the subpolar front is connected with the TWC. The northern cyclonic gyre is formed by the continuation of the TWC along the coast of Hokkaido Island, the Primorye Current and the Subpolar Front Current. The mean locations of major surface currents were explicated relative to topographic features with schematic representation of surface circulation.
Issledovanie Zemli iz Kosmosa. 2025;(3):72-84
72-84
КОСМИЧЕСКИЕ АППАРАТЫ,СИСТЕМЫ И ПРОГРАММЫ ИЗК
The sub-satellite validation system for on-orbit calibration monitoring of Russian meteorological satellite instruments and satellite products validation (cal/val system)
Resumo
This paper describes the Calibration/Validation (CAL/VAL) System for Russian Meteorological Satellites, developed between 2012 and 2016 by the Research Center “Planeta” (Roshydromet) in collaboration with research institutes of the Russian Academy of Sciences, Roshydromet, and Roscosmos State Corporation. The system is designed for monitoring of on-board calibration, external calibration (including inter-calibration with international satellite), and validation of data products. The CAL/VAL System for Russian Meteorological Satellites was developed to fulfill Roshydromet’s international commitments as a participant in the WMO and a member of the WMO Global Space-Based Inter-Calibration System (GSICS).
Issledovanie Zemli iz Kosmosa. 2025;(3):85-96
85-96