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Permafrost Environment Changes in a Warming Climateкнига
- Авторы: Mara Rossi, Dal Cin Michela, Picotti Stefano, Gei Davide, Isaev Vladislav S., Pogorelov Andrey V., Gorshkov Eugene I., Sergeev Dmitrii O., Kotov Pavel I., Giorgi Massimo, Rainone Mario L.
- Год издания: 2022
- Издательство: Frontiers Media SA
- Местоположение издательства: Lausanne, Switzerland
- Объём: 179 страниц
- Академическое издание
- DOI: 10.3389/978-2-83250-756-8
- Аннотация: Permafrost regions account for about 22% of the exposed land area in theNorthern Hemisphere (Obu et al., 2019). As one of physical characteristics in thecold environment, permafrost is sensitive to climate change. During the past decades,permafrost in high latitude and high-altitude regions shows obvious degradation,which is indicated by increasing ground temperature, deepening active layer,shrinking of permafrost area, and development of thermokarst features (Biskabornet al., 2019).Permafrost is distributed beneath the earth’s surface. Permafrost can regulate theregional water cycle and ecology from several mechanisms. First, as a weakimpermeable layer, permafrost can prevent water vertical infiltration and increasethe surface soil water content. Second, the freeze-thaw cycles of the active layer canstore excess water from summer rainfall as ice during winter, and the melting of thisice can supply soil water in the following summer. Third, ground ice melting canprovide soil water for plant growth (Sugimoto et al., 2003). Permafrost regions alsostore a large amount of soil organic carbon, which is almost twice as the carboncurrently contained in the atmosphere (Mishra et al., 2021). These carbon pools havebeen gradually accumulated and preserved during the past thousands of years due tothe low-temperature limiting the microbial decomposition of organic matter. Thepermafrost degradation may remobilize these carbon pools by releasing greenhousegases into the air. This process contributes one of the great uncertainties in theterrestrial carbon cycle feedback (Schuur et al., 2015). In addition, permafrost regionsalso store a large number of pollutants and heavy metals (e.g., mercury) which havebeen sequestrated for a long time. Permafrost degradation poses environmental risksand thawing permafrost may release these biological orchemical substances that can affect human health (Schusteret al., 2018; Miner et al., 2021).To address the issues on how permafrost environment ischanging, to what extent the changing permafrost may affectthe hydrology, ecology, carbon cycle, and pollutants, elevenmulti-discipline studies are collected in this special topic onpermafrost environment changes in a warming climate.Permafrost regions have been warming at two to threetimes the global average (Hu et al., 2021). Using the monthlyair temperature reanalysis dataset from the Climate ResearchUnit (CRU, University of East Anglia), it was found that theair freezing index in the Mongolian Plateau decreased by4.1 C d yr-1, and the air thawing index increased by2.3 C d yr−1 during 1901–2019. The northern permafrostregions showed large variabilities in freezing and thawingindex than the southern non-permafrost regions (Ma et al.). Based on the meteorological station records from 1957 to2019, the annual mean air temperature has increased by 0.031–0.039°C yr−1 in the hinterland of the Qinghai-TibetPlateau. The ground temperature within the active layer at1 m depth increased at an average rate of 0.05°C yr−1 (Zhouet al.). Along with climate warming, frequency of extremeevents also changed. On the Qinghai-Tibet Plateau, thewarmth indices such as warm days, warm nights, summerdays, and tropical nights increased at rates of 1.1, 1.6, 1.4 and0.3 days per decade from 1960 to 2016. Meanwhile, coldindices including the number of cool days, cool nights, icedays, and frost days decreased significantly (Gong et al.).These results confirmed the rapid warming of thepermafrost environment during the past decades and alsoprovide useful data to understand the changing patterns andfuture projections of permafrost.Three studies (i.e., Yang et al.; Rossi et al.; Polyakov et al.) examined the detecting permafrost and soil mappingmethod in permafrost regions. The equivalent anti-fluxopposing coils were used to eliminate the blind area forthe transient electromagnetic method, and the resultsshowed that this method solved the problem of theshallow detection blind area, eliminated the interferencecaused by the primary field, and improved the horizontaland vertical resolutions (Yang et al.). In the Russian Arctic,geophysical and geocryological methods includinglandscape microzonation, borehole drilling, groundtemperature measurements, and geoelectric surveys wereemployed to investigate the active layer thickness. Theresults showed that the multidisciplinary approach can bealso useful for other areas (Rossi et al.). In permafrostregions, soil type is one of the most fundamentalproperties because it is an important parameter for EarthSystem Models as well as the carbon stocks estimation.However, due to the harsh natural conditions, fieldinvestigation of soil types is usually costly and difficult.Using the unmanned aerial vehicle (UAV) imaging data inthe Lena River Delta, classical soil sections,geomorphological observation, and determination of themain chemical parameters of soils are presented.Although accurate mapping of soil types should be basedon chemical analysis, this result suggests that the highresolutionsoil-geomorphological maps based on theGeographic Information System and UAV data are usefulfor the mapping of soil types under the high variability of thewatershed dan cryogenic landscapes (Polyakov et al.).Permafrost significantly affects ecology and hydrology(Woo et al., 2008). A review paper in this topic summarizesthat soil water potential is widely used to describe the energystate of liquid water. The movement of liquid water in the soilis mainly determined by soil matric potential. The process ofice lenses development in permafrost has been explained bymathematical models, however, existing models might be toosimplified (Fu et al.). Therefore, new model development forice formation for micro landscapes is still largely needed. Toinvestigate the effects of hydrology on peat permafrost andcarbon process, a process-based model, i.e., HPM-Arctic, wasused the simulate the past and future changes in a peatlandecosystem in the Canadian Arctic. The results showed that theregional hydrology and basin characteristics stronglydetermined peat accumulation history and its futurechanges in organic carbon stocks under different climatescenarios (Treat et al.). For the carbon cycle in the Arcticpermafrost, a pilot study showed that extensively grazing bylarge animals can cool the ground temperature by modifyingground cover properties. In addition, the soil organic carboncontent is also higher in the extensively grazing sites than thatof non-grazing sites, which is likely attributed to the highercarbon input (Windirsch et al.).Heavy metals are anthropogenic contaminants that can betransported for long distances. Due to the atmosphericcirculation and deposition, large heavy metals have beentransported to the Arctic, Antarctic, as well as the Qinghai-Tibet Plateau. A review paper in this topic issue pointed out thatheavy metals on the Qinghai-Tibet plateau are mainly fromsurrounding heavily-polluted regions. The shrinkage of thecryosphere may increase the release of these heavy metals inthe future. This work highlights the importance of heavy metalsin permafrost environments.This special topic has collected the studies of permafrostregions located in the Arctic, Mongolia, and the Qinghai-Tibet Plateau. The results deepen our understanding ofchanging trends of climate and permafrost, interactionsamong permafrost, hydrology, ecology, carbon cycle, andrisks of heavy metals. We hope this special topic couldprovide valuable references to the researchers withrelevant interest and play an active role in promoting theresearch of permafrost changes and their environmentalimpacts.
- Добавил в систему: Исаев Владислав Сергеевич
Прикрепленные файлы
| № | Имя | Описание | Имя файла | Размер | Добавлен |
|---|---|---|---|---|---|
| 1. | Frontiers_book.pdf | Frontiers_book.pdf | 33,8 МБ | 24 декабря 2022 [vladislav69] | |
| 2. | active_layer_and_permafrost_investigation_11.2022.pdf | active_layer_and_permafrost_investigation_11.2022.pdf | 33,9 МБ | 30 ноября 2022 [vladislav69] |