Search Results (4)

The radioisotopic dating of five stratigraphic levels within the Permian succession of the Kuznetsk Coal Basin refined the ages of the corresponding stratigraphic units and, for the first time, enabled their direct correlation with the International Chronostratigraphic Chart, 2024. The analysis revealed significant discrepancies between the updated ages and the previously accepted regional scheme (1982–1996). A comparison of regional stratigraphic units’ durations with estimated coal and siliciclastic sediment accumulation rates indicated that the early Permian contains the most prolonged stratigraphic hiatuses. The updated stratigraphic framework enabled re-evaluating the temporal sequence of regional sedimentological, volcano–tectonic and biotic events, allowing for more accurate comparison with the global record. Palaeoclimate reconstructions indicated that during the early Permian, the Kuznetsk Basin was characterised by a relatively warm, humid, and aseasonal climate, consistent with its mid-latitude position during the Late Palaeozoic Ice Age. In contrast, the middle-to-late Permian shows a transition to a temperate, moderately humid climate with pronounced seasonality, differing from the warmhouse conditions of low-latitude palaeoequatorial regions. The latest Lopingian reveals a distinct trend toward increasing dryness, consistent with global palaeoclimate signals associated with the end-Permian crisis. Full article

Abrupt temperature changes and warming hiatuses have a great impact on socioeconomic systems; however, their mechanisms remain unclear. In this study, the quantitative mechanisms of the responses of abrupt seasonal temperature changes and warming hiatuses in China to their influencing factors were analysed using the monthly mean temperature (Tav), mean minimum temperature (Tnav), and mean maximum temperature (Txav) from 622 meteorological stations in China covering 1951–2018, the CMIP6 model data, and data at large spatial scales, including Atlantic multidecadal oscillation (AMO) data. The results showed that the contributions of the influencing factors to the abrupt changes in Tav, Tnav, and Txav showed large spatial variability and peaked in the spring and summer and bottomed out in the autumn. The Pacific decadal oscillation (PDO) greatly impacted the abrupt temperature changes in Northeast China and North China at a contribution rate of approximately 12%, strongly influenced the abrupt temperature changes south of the Yangtze River, and markedly influenced the abrupt temperature changes in Northwest China. The AMO had a large impact on temperature in most regions of China in all seasons except for the summer. The MEI mainly affected the abrupt seasonal temperature changes in the region between 25° N and 35° N. The Arctic oscillation (AO) substantially impacted the warming hiatuses in Northeast China in the winter at a contribution rate of approximately 12%. These influencing factors contributed less to warming hiatuses than to abrupt temperature changes. Among the regional influencing factors, AP and WS greatly impacted warming hiatuses, more so than abrupt temperature changes, while relative humidity (RH) and solar radiation (SR) contributed little to warming hiatuses. Full article

Abrupt temperature changes and warming (cooling) hiatuses have an impact on the ecological environment. Currently, research findings for the spatial variability in the years of abrupt temperature changes and warming (cooling) hiatuses covering a variety of climate zones, as well as the variation trends before and after these years, are lacking. In the present study, based on the seasonal (monthly) average minimum temperatures, average temperatures, and average maximum temperature data from 622 Chinese meteorological stations during 1951–2018, the spatial variability in the years of abrupt seasonal changes and warming (cooling) hiatuses for these three temperature types in China, as well as the variation trends before and after these years, were analyzed using the Mann-Kendall test. The results are as follows. For most stations in China, the abrupt changes in the three temperature types during each season began to occur over a wide range in the late 1980s and early 1990s, and abrupt changes did not occur at a few stations concentrated south of 30° N. After an abrupt change occurred, the average minimum temperatures and average temperatures both showed significant upward trends, while the average maximum temperatures showed significant downward trends in some regions of southern China. After five to 15 years of temperature increases (decreases) following the abrupt changes, warming (cooling) hiatuses occurred in some areas of China, with the hiatus years occurring between 1989 and 2013. These hiatuses mainly occurred in 1998 and 2007, and in terms of proximity, the stations without warming (cooling) hiatuses were concentrated south of 40° N. After nine to 17 years of warming (cooling) hiatuses, the hiatuses ended at some stations between 2013 and 2017, after which the temperatures again increased rapidly. The periods of warming (cooling) hiatuses were longer in northern China than in southern China. Currently, there are some stations where the hiatuses have not ended, suggesting that the hiatus period is apparently longer than 17 years. The years of abrupt change, no abrupt change, hiatus, no hiatus, end of hiatus, and no end of hiatus, as well as their variation trends before and after these years, have shown strong spatial variability. The results of this study have enriched the research findings on climate change. Full article

There have been hiatuses in global warming since the 1990s, and their potential impacts have attracted extensive attention and discussion. Changes in temperature not only directly affect the greening of vegetation but can also indirectly alter both the growth state and the growth tendency of vegetation by altering other climatic elements. The middle-high latitudes of the Northern Hemisphere (NH) constitute the region that has experienced the most warming in recent decades; therefore, identifying the effects of warming hiatuses on the vegetation greening in that region is of great importance. Using satellite-derived Normalized Difference Vegetation Index (NDVI) data and climatological observation data from 1982–2013, we investigated hiatuses in warming trends and their impact on vegetation greenness in the NH. Our results show that the regions with warming hiatuses in the NH accounted for 50.1% of the total area and were concentrated in Mongolia, central China, and other areas. Among these regions, 18.8% of the vegetation greenness was inhibited in the warming hiatus areas, but 31.3% of the vegetation grew faster. Because temperature was the main positive climatic factor in central China, the warming hiatuses caused the slow vegetation greening rate. However, precipitation was the main positive climatic factor affecting vegetation greenness in Mongolia; an increase in precipitation accelerated vegetation greening. The regions without a warming hiatus, which were mainly distributed in northern Russia, northern central Asia, and other areas, accounted for 49.9% of the total area. Among these regions, 21.4% of the vegetation grew faster over time, but 28.5% of the vegetation was inhibited. Temperature was the main positive factor affecting vegetation greenness in northern Russia; an increase in temperature promoted vegetation greening. However, radiation was the main positive climatic factor in northern central Asia; reductions in radiation inhibited the greenness of vegetation. Our findings suggest that warming hiatuses differentially affect vegetation greening and depend on meteorological factors, especially the main meteorological factors. Full article